ACID HYDROLYSIS OF REFUSE
U S  ENVIRONMENTAL PROTECTION AGENCY

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This report has been reviewed by the U.S.  Environmental Protection
Agency and approved for publication.  Approval does not signify that
the contents necessarily reflect the views and policies of the U.S.
Environmental Protection Agency, nor does  mention of commercial products
constitute endorsement or recommendation for use by the U.S. Government.

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                   ACID HYDROLYSIS OF REFUSE
       This final open-file report (SW-15rg.of) on work
        performed under solid waste management research
     grant no. EC-00279 to Dartmouth College was written by
      ROBERT D. FAGAN and, except for minor changes in the
introductory pages, is reproduced as received from the grantee.
             U.S. ENVIRONMENTAL PROTECTION AGENCY
                             1971

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      An environmental protection publication
in the solid waste management series (SW-15rg.of).

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                              CONTENTS
ABSTRACT

INTRODUCTION
1.   SOLID WASTE AND ITS DISPOSAL                                    4
     1.1 Current Disposal Methods                                    4
     1.2 Refuse Composition                                          4
     1.3 Utilization of Municipal Refuse                             8
     1.4 Summary of Alternatives                                     8

2.   THE HYDROLYSIS OF CELLULOSE                                    11
     2.1 The Chemistry of Cellulose                                 11
     2.2 Dilute Acid Hydrolysis of Wood Cellulose                   13

3.   EXPERIMENTAL APPARATUS AND PROCEDURE                           20
     3.1 Kinetic Model                                              21
     3.2 Isothermal Kinetic Study                                   22
     3.3 Acid Injection Bomb                                        25
     3.4 Nonisothermal Kinetic Study                                26

4.   EXPERIMENTAL RESULTS AND ANALYSIS                              29
     4.1 Isothermal Analysis Results                                29
     4.2 Non-Isothermal Analysis Results                            31
     4.3 Experimental Analysis Conclusions                          41

5.   PLANT DESIGN                                                   44
     5.1 Separation and Pretreatment System                         46
     5.2 Hydrolysis Reactor System                                  51
     5.3 Concentration of Sugar Solution and Heat Recovery          57
     5.4 Design Calculations                                        61

6.   PLANT ECONOMICS                                                74
     6.1 Capital Costing Procedure                                  74
     6.2 Manufacturing Cost Estimation                              78
     6.3 Manufacturing Cost Analysis                                80
     6.4 The Marketability of a Glucose Solution                    88
                                 iii

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                                                                  Page
7.   GLUCOSE AS A POTENTIAL RAW MATERIAL                            95
     7.1 Monosodium Glutamate                                       95
     7.2 Citric Acid                                                96
     7.3 Butanol                                                    96
     7.4 Lactic Acid                                                96
     7.5 Sorbital and Oxalic Acid                                   96
     7.6 Conclusions                                                97

8.   RECOMMENDATIONS FOR FUTURE WORK                                98
     8.1 Metal Ion Effect on Hydrolysis                             98
     8.2 Flow Reactor                                               99
     8.3 General Plant Considerations                               99
     8.4 Sugar as a Raw Material                                   100

9.   SUMMARY AND CONCLUSIONS                                       101

REFERENCES                                                         104

Appendix I      QUANTITATIVE SACCHARIFICATION                      107

Appendix II     SUGAR TEST                                         108

Appendix III    NONISOTHERMAL HYDROLYSIS RESULTS                   113

Appendix IV     COMPUTER PROGRAMS                                  116

TABLES

1-1  Composition and Analysis of an Average Municipal
       Refuse                                                         4

1-2  Municipal Solid Wastes Composition                               5

1-3  Packaging Materials Consumption                                  7

1-4  Alternative Disposal Methods                                   10

4-1  Quantitative Saccharification                                  32

4-2  Carbohydrate Composition of Kraft Paper Pulp                   32

5-1  Material Balance - Representative 250 Ton Plant              63-64

5-2  Evaporator Design Data                                         73

6-1  Manufacturing Cost Analysis                                    79
                                  IV

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                                                                  Page

6-2  Effect of Acid Concentration and Temperature
       on Manufacturing Cost                                         82

6-3  Ethanol Production by Fermentation - Cost Analysis              92

FIGURES

2-1  SUGAR YIELD VERSUS RESIDUAL POTENTIAL SUGAR                     18

4-1  SUGAR YIELD VERSUS REACTION TIME                                30

4-2  LOG (PRE-EXPONENTIAL FACTORS) VERSUS LOG (ACID
       CONG.)                                                        35

4-3  SUGAR YIELD VERSUS NONISOTHERMAL TEMPERATURE  (TIME)             37

4-4  SUGAR YIELD (KRAFT FIBERS) VERSUS NONISOTHERMAL
       TEMPERATURE                                                   39

4-5  PREDICTED ISOTHERMAL SUGARS VERSUS TIME                         42

5-1  SEPARATION SYSTEM                                               47

5-2  REACTOR SYSTEM                                                  48

5-3  EVAPORATION AND'HEAT RECOVERY                                   49

5-4  CORROSION RATE OF CARPENTER STEEL                               55

5-5  MATERIAL BALANCE SHEET                                          65

6-1  CAPITAL & MANUFACTURING COST ANALYSIS - REPRESENTATIVE
       250  TON PLANT                                             76-77

6-2  SUGAR COST VERSUS PLANT CAPACITY                                84

6-3  CAPITAL COST VERSUS PLANT CAPACITY                              85

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                                ABSTRACT







     To recover some of the value of municipal solid waste, a new dis-




posal process was studied which uses the cellulose portion of refuse,




mainly paper, as a raw material for the production of sugar by acid




hydrolysis.  Experiments to predict the sugar yield were performed,




and the resulting information was used in the design of a proposed




hydrolysis plant to establish the economics of the system.




     A sugar yield of 51% is predicted with 1% acid at 230°C.  With




this yield it is concluded that sugars from the hydrolysis plant can




be produced at costs competitive with molasses sugars.  This conclusion




is valid for municipalities with populations greater than 200,000,




producing refuse containing 50% paper, or populations of 100,000 pro-




ducing refuse containing 60% paper.  It is also shown that such sugars




could be used to produce ethanol at a price comparable to the existing




market price.  Refuse disposal by acid hydrolysis under these conditions




might save $600,000 a year for a community of 200,000 people which was




previously disposing of its waste at $3/ton.

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                              INTRODUCTION







     The lowest predicted disposal cost for modern incineration is




$3/ton.     At this rate, solid waste disposal would cost a city of




approximately 200,000 people $600,000 per year.  Andrew Porteous, a




1967 graduate of Thayer School of Engineering, Dartmouth College, pro-




posed a disposal process which would utilize refuse as a raw material.




Porteous' process consisted of hydrolyzing the available cellulose con-




tent of refuse, mainly paper, to sugar.  The sugar in turn could be




used to produce the saleable product of ethanol by fermentation.  His




economic study showed that in some cases such a process would not only




eliminate the disposal cost but make a profit as well.




     Because of the great economic potential of the process, a research




program was established to study the process in greater depth.  Porteous'




economic analysis was based on the assumptions that (1) paper cellulose




would hydrolyze like wood cellulose, and (2) the kinetic model experi-




mentally determined for wood cellulose at temperatures below 200°C could




be used to predict higher yields at 230°C.  In order to test these




assumptions it was necessary to establish new hydrolysis techniques




and perfect quantitative analysis procedures for sugar and cellulose.




The information gained from laboratory work and process analysis was




used to modify Porteous' original process design and reevaluate the




economics of the system.
                                  - 3 -

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                                - 4 -
1.  SOLID WASTE AND ITS DISPOSAL







1.1  Current Disposal Methods




     There are currently just two acceptable means of solid waste




disposal—incineration and sanitary landfill; the former requires a




large capital investment, and the latter, large areas of available




land.  The cost of disposal varies with the area, and ranges from $1 to




$12 per ton with an average value of approximately $4.50 per ton.




1,2  Refuse Composition




     A knowledge of the composition of solid waste is necessary, if any




technological advancement is to be made in the field of solid waste




disposal.  The classification of solid waste by weight and composition




is hampered by its heterogeneous composition and its offensive nature.




Table 1-1 is a breakdown of solid waste by composition derived from a



                  (2)

study done by Bell    in 1963.  Table 1-2 is a compilation of municipal




solid waste composition obtained through the Public Health Service.




     The actual composition of municipal refuse varies with the location




sampled and the season of the year.  Thus it is difficult to arrive at




a set average composition for the country.  Generally, it is possible




to say that paper is the main component of refuse, 40 to 60% by weight,




followed by food waste, and then metal and glass products.  It is




believed that there will be an increasing amount of paper and synthetic




materials produced each year.  A large part of this waste is derived



                                    (3)
from packaging material.  Table 1-3    shows the increasing trend of




solid waste produced from packaging material consumption alone.  An

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- 5 -
.-1
          (2)
Approximate
Percent of Analysis
Total "as received"
Refuse basis, moisture
Ruoo^sn, o 4 'o
Paper, mixed
V:GOC and bark
Grass
j_j r u s ii
Greens
Leaves , rips
Leather
Rubber
Plastics
Oils, Paints
Linoleum
Rags
Sweepings, street
Dirt, household
Unclassified
Focc. wastes, 12%
Garbage
~ a c s
Nor.combustibles , 24%
Xe'callics
Glass and Ceramics
A s n e s
Organic Analysis of Composi

Moisture
Cellulose, Sugar, Starch
Lipids (fats , oils , waxes)
Protein, 6.25N
Other organic (plastics)
Ash, metal /glass , etc.

Analysis of Composite
Moisture 20.73
Carbon 28.00
Total Hydrogen 3.50
Available Hydrogen 0.71
Oxygen 22.35
Nitrogen 0.33

42.0
2.4
4.0
1.5
1.5
5.0
0.3
0.6
0.7
0.8
0.1
0.6
3.0
1.0
0.5

10.0
2.0

8.0
6.0
10.0
te
Percent
20.73
46.63
4.50
2.06
1.15
24.95
100.00
Refuse, As
Sulfur

10.24
20.00
65.00
40.00
62.00
50.00
10.00
1.20
2.00
0.00
2.10
10.00
20.00
3.20
4.00

72.00
0.00

3.00
2.00
10.00









Received Basis
0.16
Non Cora. 24. 93
Ratio
Btu/Lb
C: (H) 39.4
4,917
Btu, dry 6,203
Btu, M
and AF 9,048
                        Weight
                        percent
                        Volatile
                        Matter
                         75.94
                         67.89
                         26.74

                         68.46
                         83.98
                         64.50
                         84.34
                         54.00
                         20.54
                         20.26
                          0.5
                          0.4
                          2.68

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                «"7 »-
          Table 1-3




PACKAGING MATERIALS CONSUMPTION


MATERIAL
Paper & Paperboard
Glass
Metals
Wood
Plastics
(Ref. (3) )
MILLIONS
1966
25.2
8.2
7.1
4.1
1.0

OF TONS
1976
36.9
11.9
8.4
4.4
2.5
                   45.6      64.1

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accurate study of waste composition is necessary before a municipality




can make a reliable decision on what method of disposal would be most




economic for its community.




1.3  Utilization of Municipal Refuse




     Since paper is the main component of waste, it is desirable to




devise recycling processes using paper as the raw material.  Porteous




suggested a process which would convert the cellulose portion of paper,




approximately 75%, to glucose by means of sulfuric acid hydrolysis.




The basis for the hydrolysis is that cellulose is a polymer composed




of individual glucose units.  The glucose can be used as a raw material




for fermentation to ethyl alcohol.  In this manner, the bulk of the




refuse is converted to a utilizable raw material, which can be sold to




cover the disposal cost of the residual waste.  Since the residual




waste is inert, it can be disposed of at a lower cost than can the raw




refuse.  Porteous' preliminary study showed the process has an economic




advantage over all other existing means of disposal, thus warranting




further study.




1.4  Summary of Alternatives




     Table 1-4 summarizes the available disposal methods and their re-




lated disposal cost.  Incineration and sanitary landfill are the only




disposal alternatives open to most cities.  Since land is becoming more




scarce, the cost of sanitary landfill will continue to increase for




many municipalities.  Although heat recovery systems and other techno-




logical improvements in incineration will help cut cost, there will




always be some associated disposal cost.  With this as a basis, it is

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                                 - 9 -
   Method


Open Burning

Sanitary Landfill

Incineration


Composting
          Table 1-4

ALTERNATIVE DISPOSAL METHODS


          Comments


    No longer legal

    Requires large land areas

    Must contain antiair
    pollution devices

    Little available market.
    Depends on dumping fee
Cost $/Ton
  1-12
  3-7
                                                               2-7

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                                 - 10 -
seen that refuse will have to help pay for its own disposal cost.   Using




refuse as a raw material for the production of sugar by acid hydrolysis




is one such attempt at accomplishing this goal.

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 2.  THE HYDROLYSIS OF CELLULOSE





     The concept of hydrolyzing cellulose containing materials



 to sugar is not a new one.  Meiler and Scholler  '  in 1923



 studied the acid hydrolysis of cellulose dextrine and the first



 plant to convert wood to sugar with subsequent fermentation was



 built in Germany just prior to World War II.  This plant was



 built to offset the ethanol shortage which existed during that



 period.  The principal research conducted in the U.S. was by



 Saeman' '  who was contracted by the War Production Board during



World War II to develop a practical process for producing



ethanol from wood waste.  Saeman's work established the kinetic



model which describes the hydrolysis of cellulose in dilute



acid solutions.



2.1  The Chemistry of Cellulose



     Cellulose is a fibrous tissue found in the cell walls of



plants and trees.   It is a polysaccharide composed  of long



chains of  glucose units, a six carbon carbohydrate,  connected



at hydroxyl groups,  glycosidic bonds.
          OH   ^
                           -11-

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                             -12-
      The other  polysaccharides which are  found in the colls of



 plants are  called  hemicelluloses.  They are unrelated to cellu-



 lose and consist of  pentose units, a five-carbon carbohydrate.



      Cellulose  is  the main component of paper and the amount of



 cellulose in  the paper varies with the grade of paper produced.



 The  pulp used for  naking paper is prepared from wood by choiaicul



 or mechanical treatment.  This treatment  breaks down the wood



 fibers,  eliminating  the lignin and most of the easily destroyed



 hemicellulose.  The  main methods of pulping, with their result-



 ing  cellulose contents are:  Sulfite 86%, Kraft 80%, and me-



 chanical 50%.   The exact amount of cellulose in any given type



 of paper depends on  which pulp or pulps are used and the amount



 of filler which is added to the paper.  The amount of cellulose



 in paper ranges from approximately 95% in rag paper to 50% in



 newspaper.



      Cellulose  and hemicellulose undergo  the following hydrol-



 ysis  reactions  with  acid acting as a catalysis:




            ACID
  Cellulose 	>Hexose 	> decomposition products acids



                ACID
  Hemicellulose	> Pentose	> decomposition products furfural





 The hydrolysis  reactions can be either homogeneous or hetero-



 geneous,  depending upon the acid concentration of the solution.



 Hemicellulose is an  easily hydrolyzable material which will



 yield mainly  the pentose, xylose, which upon further reaction



 produces  furfural.   The more stable of the two, cellulose,



•upon  hydrolysis yields glucose, which subsequently decomposes



 to hydroxymethylfurfural and finally levulinic and formic acid.

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                            -13-
      In its  natural  state,  cellulose  is not  only  linked  by



 glycosidic bonds  but by  hydrogen bonding  in  a  crystalline



 lattice.  Cellulose  is soluble  in  concentrated solutions of



 72?.  sulfuric,  35% phosphoric, and  45% hydrochloric acid.  In



 such solutions  the hydrolysis reaction is  first order  homo-



 geneouo and  due to the low  reaction temperatures  proceeds with



 very little  decomposition of the sugars.   A  process based upon



 high acid concentration  would give high yields  of sugar, but



 the  high cost associated with using large  amounts of acid



 places  the process in an undesirable economic  state.   Dilute



 acids,  less  than  2%, can be used if the reaction  temperature is



 increased.   This  reaction is heterogeneous,  since the  crystal-



 line state of the cellulose remains intact.  The  exact kinetic



 mechanism of the  reaction is not known but the  results have


                                 Kl     K2
 been modeled with a  standard  A 	> B 	)  C   irreversible



 reaction rate model.  Sulfuric and hydrochloric acid with their



 high ionization coefficients are the best  catalysis for  the



 reaction since  they  give the highest ratio of rate of  formation



 to rate of decomposition of sugar.  Sulfuric acid is usually



 preferred for use  since  it is easier to handle  and less  costly



 than  hydrochloric  acid.



 2.2   Dilute Acid  Hydrolysis of Wood Cellulose



      Porteous'  original process^)  for waste disposal by cellu-



 lose  hydrolysis was based on a kinetic study performed by



 SaemanC?) on wood.  Saeman attempted to show that the hydrolysis



 of wood cellulose  in dilute sulfuric acid could be described by

      K!   K2i                                         KI

an  A —> B —* C  consecutive reaction with cellulose 	»

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                            -14-






                 K2
 reducing sugars  	) sugar decomposition products.  Saeman



 performed his experiments in sealed glass bombs heated by



 direct steam in a rotating digester.



     The rate constant for the decomposition of the sugars, K2,



 was determined by reacting sugar solutions in the glass bombs



 at temperatures from 170° to 190°C with acid concentrations



 from 0.4 to 1.6%.  The decomposition of both hexose and pentose



 sugars was studied and it was found that glucose, the main



 component of cellulose, was the most stable.  Plots of the



 logarithm of the residual sugar concentrations versus reaction



 time gave straight lines.  Since the integrated equation of a
first order reaction is, B = B e  ^ , the logarithm of the



concentration,  log B = log BQ - K0T ,  will give a straight



line with the slope equal to K2.  Saeman's results, therefore,



showed that the reaction was first order.  The results of this



experimentation are summarized in the following empirical



equations taken from Saeman's work.



          P.ate Constants for Sugar Decomposition


                                . 32.700

      K2  =  1.86 x 1014 C1'02 e   RT                       d>



                                 -32870

      K2  =  2.39 x 1014 C1'02 e   KT~                      (2)




with  C = concentration of acid



      R = 1.93 cal/g mole deg. K



      T = Temp. deg. Kelvin



     Equation (1)  was derived by measuring the residual reducing



sugar content of the solution and equation (2), by measuring the



residual fermentable sugar content.  Since sugars act as a re-



ducing agent,  a simple analysis for sugar is a test of the

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                             -15-
 rcducing  power  of  the  solution.  Although valid when degraded



 sugars  are  not  present,  it gives false values when degraded



 sugars  are  present.  This is  explained by the additional re-



 ducing  power  of the  first oxidation state of glucose.  The only



 reliable  measure is  based on  equation  (2) which is calculated



 with  a  test specific for glucose.  This equation was derived



 using a pure  homogeneous glucose solution and is only a means



 of  approximating the reaction rate for the actual decomposition



 of  sugars in  the presence of  wood cellulose.



      The  rate constant for the formation of sugar from cellulose,



 Kl7 was determined by reacting ground samples of Douglas fir



 wood  with a dilute acid solution in the heated glass bombs.



 After a measured period of time the vessels were quenched and



 analyzed  for the unreacted wood cellulose content.  Since wood



 is  not  entirely  cellulose and no direct measure of cellulose



 content is  possible, an indirect method of quantitative sacchari-



 fication was employed to measure the cellulose content.  The



 unreacted wood cellulose, referred to as the residual cellulose,



 was washed  free  of the dilute acid-sugar solution and reacted



 under conditions which gave quantitative yields of sugar without



 sugar decomposition.  Consequently the quantitative saccharifi-



 cation  procedure described in Appendix I uniquely measured the



 residual cellulose of the sample.   Obviously when the quanti-



 tative  saccharification is applied to an unreacted sample of



wood,  it determines the original cellulose content of the wood,



which is referred to as the potential sugar yield of the sample.



When  the quantitative saccharification is applied to a reacted



 sample of wood  (residual),  it gives the remaining cellulose con-



 tent which is  referred to as  the residual potential sugar yield.

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         -17-
      The high activation energy of rate constant


 that although it was derived for a heterogeneous sc


 reaction, the reaction is not mass transfer controlled.   The


 higher the activation energy,  the more temperature  dependent


 the reaction is.   Since diffusion is  not so temperature  de-


 pendent, it is concluded that the reaction is  not diffusion


 controlled.

                  Kl   K2
      With the  A—> B —> C  irreversible reaction,  as  the


 reaction proceeds,  the cellulose concentration,  A,  decreases,


 the decomposed products concentration,  C,  increases, and the


 glucose yield,  B,  goes through a maximum.   This  yield  of in-


 terest is that of  glucose,  the maximum value of  which  is given


 by



     max  ~  K2



 This equation is derived from  the integrated  equations for


 the reaction in section 3.1.   Since the empirical equations


 (2)  and (3)  for Kn  and K0  show that   K-,  will  increase faster
                         &              •!•


 than  K2  with an  increase  in  acid concentration or temperature,


 the maximum  yield  of  glucose,  equation  (4),  should  also  increase


-with these  conditions.  This  was shown by  Saeman in his origi-


 nal work^  '  to  be  true  over  the  range of 170 to  190°C.   On  this


 basis  Porteous  extrapolated  Saeman's data to 230°C  with  a 0.4%


 acid concentration, and predicted a yield of 55%.   Figure 2-1


 taken  from a more recent publication of  Saeman's  work'^)  shows


 that a  yield of approximately  47%  was obtained under these  con-


 ditions.   There was no  explanation of the discrepancy between


 the  predicted and experimentally  obtained results.
K2 \

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                             -18-
                         Figure  2-1


         SUGAR YIELD  versus RESIDUAL POTENTIAL SUGAR
'J
-f
\~
LJ

Z
   olil
    loo

                                                                     1

BO
                              1C
                                      U&AK_(%OP INITIAL)

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                           -19-
     Sacnan's empirically derived results only hold for the



crystalline portion of cellulose and most cellulosic material



contains both amorphous and crystalline cellulose.  £ leman ;. i -



found that cotton cellulose decomposed at a rate different, frcrn



that of wood cellulose.  The rate of hydrolysis of paper cellu-



lose, especially at higher temperatures, therefore, cannot be



strictly inferred from Saeman's work since its crystalline



structure may be modified both by the paper making process and



any pretreatment performed in the hydrolysis process.  The



kinetics and yields associated with paper cellulose hydrolysis



had to be found experimentally before a hydrolysis process for



refuse paper could be designed.

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 3.  EXPERIMENTAL APPARATUS AND PROCEDURE





     An experimental program was established to determine the



 ultimate potential of refuse hydrolysis as a solid waste dis-



 posal process.  Since Porteous based his preliminary economic



 study on an extrapolation of Saeman's kinetics for wood cellu-



 lose, it was necessary to determine whether such an assumption



 was valid.  If it were found that paper hydrolyzed at a dif-



 ferent rate than wood cellulose, then a model for paper hydrol-



 ysis would have to be determined.  Although it was not necessary



 to determine exactly what reaction was occurring, a model for



 predicting the yield under various conditions of hydrolysis



 had to be found.  Such a model was necessary for the design of



 the hydrolysis plant and the determination of the most econom-



 ical operating conditions for the plant.  Once this information



 was obtained, the total economics of the system could be de-



 termined.



     The laboratory apparatus had to contend with the high



 temperature (>220°C), high pressure (>400 psi), and the cor-



 rosive atmosphere anticipated for the process.   Moreover, the



 fact that the yield of glucose reached a maximum in a short



 time made the design of a reliable laboratory procedure very



 difficult.



     A quantitative saccharification procedure which would



 completely hydrolyze cellulose to glucose without decomposition



 products is found in Reference 9 and summarized in Appendix I.



This experimental analysis is based on initial  high acid con-



 centration, 72%  H2S04,  to dissolve the cellulose at room
                             -20-

-------
                             -21-

 tcr.Vjeraturo,  follov/ecl by  treatraent with diluted 4%  H^SO, at

 an  elevated,  temperature.   This  procedure determines the poten-

 tial glucose  in  any  cellulosic  material such as refuse, and is

 essential  in  any kinetic  study  since the original amount of

 cellulose  must be known before  the kinetic parameters can be

 iatvjirpixtccl.  The glucose  analyses v/crc performed with an

 C-toluidine colorirr.etric  test described in Reference 9 and

 modified by Dr.  Sanka, Mary  Hitchcock Memorial Hospital, Hanover,

 N.H., for  work in blood and  urine  sugar analysis.   This test is

 outlined in Appendix  II.   It is a  micro test based on the spe-

 cific reaction of aldohexoses with 0-toluidine in accordance

with Beers Law.

 3 . 1  Kinetic Model

     SaemanC?) showed that the hydrolysis  of the  resistant

wood cellulose is described  by an   A — i — »  B  — ^ — >  C  reaction

governed by the  following equations.   (A = cellulose,  B =

glucose, C = decomposed sugar).
         3CS
              ~   K2CB + K1CA
Integration of (5) and  (6) gives
    P
    JL.   =  e~Kl6                                        (7;


    r~*        T/1     \ ^

    C^  =  (K2 ~ KX)                                     (8)


    CB(MAX)      , Kl ;    A / K2  I                          (9)

-------
                            -22-
            inKo - inKi
     6*  -   	±	£                                    (10)

             K2 - KI



where   CA   =  concentration of A



        Cj.   =  initial concentration of A

         A0


         8   =  time



         a*  =  time to max yield of B



         Kj_  =  reaction rate constant for A to B reaction



         K   =  reaction rate constant for B to C reaction



     The classical experimental approach for determining rate



constants was used by Saeman.  He assumed isothermal conditions



for  the reaction and that the heat up and cool down time for



his  glass vessels would be negligible when compared with the



raction time for temperatures below 190°C.  The amount of



original and subsequent cellulose was determined by a quanti-



tative saccharification.  Thus, by reacting the cellulose for



various lengths of time, the log of the cellulose concentra-



tion versus time could be plotted and the first order rate



constant  KJL  determined.  The same procedure was used to de-



termine the first order reaction rate constant  K^  with the



cellulose replaced with a known concentration of glucose.



     Saeman's experimental equipment limited his reaction tem-



perature to a maximum value of 190°C, but extrapolation of



Saeman's results indicated that a higher yield could be ex-



pected at higher temperatures.



3.2  Isothermal Kinetic Study



     The first experimental procedure was designed to determine



if Saeman's data could be extrapolated to temperatures above



190°.  It was thought that a simple approach to this problem



would be to assume that Saeman's empirically derived equation  (2)

-------
                            -23-
 for  the  decomposition  rate  of  glucose would  hold  for  higher


 tempera.cures.  Therefore, knowing  the original  concentration


 of cellulose  from  a quantitative saccharification  ¥-2  from


 equation (2)  and the yield  of  glucose versus  time from  experi-


 mentation,  it would be possible to determine  K^   by  a  trial


 and  errGf  solution involving" equation1  (8) .   If  tYiQ de'tSIrnineu


 values of   K,  were the same as those predicted by Saeman's


 empirical  equation (3), it  would be concluded that the  hydrol-


 ysis of  paper cellulose is  the same as the hydrolysis of wood


 cellulose  and Saeman's  empirical equations would  be valid  for


 such work.


     Initial kinetic studies were performed in  1"  x 4"  stain-


 less steel  (316) nipples capped and sealed with Teflon  tape.


 The reaction  temperature was obtained by placing  the  reaction


 vessels  into a high temperature oil bath.  A  temperature-time


 history  was recorded by sealing a chromel-alumel  thermocouple


 in one of  the vessels.  A number of preliminary tests gave in-
   /

 consistent results with very low yields.  Since it was  thought


 that the acid was reacting with the vessels and causing lower


 than expected yields, a 25 x 100 mm glass culture  tube was


 placed in the stainless steel vessels.  This  alleviated the


 corrosion problem and increased the measured  yield by 300%.


A new temperature-time curve was recorded and all remaining


tests were made using the glass liner.  0.2 gr brown paper bag


 samples were prepared by cutting up the bag into approximately


 1/10" squares.  The samples were placed in glass culture tubes


and 5 ml of 0.5 percent sulfuric acid solution was added.   The


glass tubes were then sealed in the stainless steel vessels

-------
                            -24-


and placed in the constant temperature bath for a measured

period of time.  At the end of this time the vessels were

quenched in ice water, and analyzed for glucose content.  The

heat of reaction for cellulose decomposition is approximately

10 K cal/g-mole.  Therefore the adiabatic temperature rise was

calculated to be 2°C under the experimental conditions used

in this study.  However, the conditions are far from adiabatic;

hence the error in neglecting heat effects of the reaction was

certainly less than 2°C.  An experimental temperature-time

trace indicated isothermal conditions after an initial heat-up

period, the reactor temperature being a constant 4°C below the

indicated bath temperature.

     A corrected isothermal reaction time was determined as

follows
where:

   ti  =  reaction time used in kinetic calculations

   t^  =  time that sample resides in bath

   t3  =  time to heat sample from room temperature
          to 170°C in the bath, as determined from
          a heat-up curve

   t4  =  time to heat from 170°C to final bath
          temperature

     The main cause of error in kinetic calculations Was the

time to heat the sample from 170°C where the reaction rate

first becomes significant, to the final temperature.  This

heat-up time was found to be between 2 and 3 minutes ;  thus

for temperatures above 210°C and reaction times approaching

3 minutes, the error due to heat-up was very large.

-------
                              -25-
 3 . 3  Acici  Inj_cction Bomb


     The isothermal kinetic analysis based on the results of


 the  experimental procedure outlined in Section 3.2 w ,s in error


 due  to the time necessary for the bombs to reach isothermal


 conditions.  It was believed that this error could be elimi-


 nated by building an acid injection bomb system.  Such a systom


 was  constructed using a 2" x 4" SS-316 pipe with a glass liner


 as the reactor.  The reactor, charged with 150 ml of water and


 0.5  grams of paper, was heated in a high temperature bath until


 it reached the desired temperature.  The hydrolysis was ini-


 tiated by injecting 1 ml of acid through a three way ball


 valve by nitrogen pressure.  After a measured period of time
                                                            /•

 a sample was drawn off and flashed to room temperature.  It


 was  found that the reactor required more than two hours to


 reach isothermal conditions and that during this time the


 paper had undergone thermal degradation.


     The initial paper-water charge volume was kept large


 compared to the injected acid volume to prevent the lower


 temperature acid from cooling down the reactor.   Using less


 than 1 ml of acid solution would result in large error in the


 final desired acid concentration,  due to  transfer losses in


 the valve and tubing.   Although a smaller reactor volume would


 have a shorter heat up time,  the required high volume ratio


 and lower limit on the injected acid volume prevented the use


of such a system.   An attempt to circumvent the  thermal de-


gradation was made by injecting a  fine paper slurry into the


reactor.   The reactor  was  charged  with 150  ml of  0.5% acid


solution and brought to the desired temperature.   5 ml of

-------
                                -26-





watcr with 0.1 gram of powdered paper was then injected into



the reactor.  it was found that the paper failed to pass freely




through the valves and tubing into the reactor.  The modifi-



cations necessary to allow•such operation precluded its use



for such experimentation.




3<4  Nonisothermal Kinetic Study



     Due to the difficulties of obtaining an isothermal system,



a new approach to the problem was attempted.  It was believed



that a non-isothermal kinetic analysis could be performed by



means of a modified curve fitting routine.  It was assumed that



the proposed  A —=-> B —=-) C  kinetic model was valid and that



the rate constants followed Arrhenius'  equation,  K = Ce~A^'    .



There are then at a given acid concentration four parameters,



the two pre-exponential constants (C's)  and two activation



energies  (AH's), which had to be calculated to determine the



overall kinetic model.  The following method was used to de-



termine these parameters.



     A sample of paper or refuse which had been run through a



Wiley ball mill to produce 2 mm particles was placed in a glass



culture tube with a specified amount of acid solution.  This



vessel was placed in a 1" x 4" stainless steel nipple and



sealed.  The cap of the nipple was taped with a 1/4" N.P.T.



such that a Swagelock thermocouple well connector could be



screwed into the cap.  The thermocouple well consisted of a



1/4" stainless steel tube coated with Teflon tape.  A chromel-



alumel thermocouple was placed in the well, which had been



previously filled with oil,  to measure  the liquid temperature



within the vessel.  This vessel was placed in a constant tem-



perature bath which had been set at 260°C.  A constant record

-------
                                   -27-
 of the temperature-time  history was  kept by use of a thermo-


 couple! chart  recorder.   Samples were removed from the bath


 at various  intervals  of  temperature, quenched in ice water,  and


 analyzed  for  sugar  content.   Six to  eleven  samples were used


 for each  acid concentration  run,  and at the start of each acid


 run a  sample  quenched when the  temperature  reached 180°C was


 analyzed  for  both sugar  and  residual potential sugar (cellulose)


 content.  The data  obtained  from such a procedure consisted  of


 1)  quantitative potential sugar (cellulose  content)  at 180°C,


 2)  sugar  yield at intervals  of  temperature,  and 3)  temperature-


 time history.  The  differential equations which describe such


 a  system  are:


    3 A
33
                                                            (11)




                 - K2B(t)                                   (12)
   0 t


where  A   =  concentration of cellulose


       B   =  concentration of sugar


       Kl  =  C1e"AHl/RT  =  rate constant 1

                 -AH9/RT
       K2  =  C2e   *     = rate constant 2


       R   =  1.98 cal/g deg. K


       T  -   deg. Kelvin


       t  =   time


     With calculated initial conditions on A and B at 180°C, a


temperature-time function derived from a 4th order polynomial


curve fit for the data, and values for C]_, AH]_, C2, AH2, equa-


tions (11)  and (12)  could be numerically integrated for the


sugar yield as a function of time.  It was necessary to search


for the values of C]_,  AH]_,  C2/  and AH2  which resulted in yields

-------
                             -28-





of sugar which best agreed with those obtained experimentally.



Once such  parameters were determined from the non-isothermal



analysis, the kinetic model could be used to predict the yield



for an isothermal reaction.



     A Hooke-Jeeves pattern search^  '  and a Runge-Kutta numer-



ical analysis were used to determine the rato constant para-



meters which minimized the sum  of the square errors between



the predicted and the experimental sugar yields.  Insurance of



convergence was determined by generating hypothetical experi-



mental yields with four given parameters, and using these



yields to repredict the parameters with the previously des-



cribed computer program.  The final sum square error from



this analysis was  1 x 10~6  and convergence was obtained in



120 seconds on a G.E. 630 time-sharing system.

-------
 4.   2XPERIMZXTAL  RESULTS AND ANALYSIS





      The apparatus  and  procedures  described .in  Chapter  3  were



 used to  determine the yields and kinetics of paper hydiolysis.



 It  was found  that an accurate kinetic  analysis  based  on iso-



 theraal  conditions  would not be possible.  Reaction half  lives



 of  less  than  one  minute were expected  at temperatures >220°C,



 and under such  fast reaction conditions it was  not possible to



 build an apparatus  with a heat-up  time small enough to  be



 ignored.   A non-isothermal kinetic analysis was therefore used



 in  determining  the  kinetics of the reaction.



 4.1  Isothermal Analysis Results



      A preliminary  study of acid hydrolysis was performed with



 temperature conditions  which were  to be isothermal.  Runs were



 made  at  bath  temperatures of 200°C, 210°C, and  220°C.   The



 yields of  sugar on  a weight sugar/weight paper basis are  shown



 in  Figure  4-1.  A kinetic study was performed on this data as



 indicated  in  Section 3.1, but it was hampered by an inaccurate



 quantitative  saccharification procedure and the actual  non-



 isothermal state of the system.



     An  accurate quantitative saccharification is essential



 since a  knowledge of the amount of cellulose in the paper is



 needed to correct yields to a weight sugar per weight potential



 sugar (cellulose)  basis.  This change of base is necessary since



 the kinetic model is for the hydrolysis of cellulose,  and paper



 is not 100% cellulose.   The main difficulties in the quanti-



ta-c_ve saccharification were caused by lack of a suitable  low
                            -29-

-------
                                 -30-

                            Figure 4-1
                   SUGAR YIELD versus REACTION TIME
10
        \?    2.20°
                                                  \
                                                              \
                      10
                                          20
                          TIME.

-------
                             -31-
 tenpcrature bath  for the first step of the analysis and by



 using  too  large a particle size in the procedure.  The time



 necessary  to reach  isothermal conditions also caused error



 which  could not be  neglected in a kinetic analysis.



     In  spite of  these difficulties the data obtained showed



 that paper could  be hydrolyzed to sugars and that the yield, of



 sugar  passed through a maximum as would be expected if the



 proposed reaction sequence held.  Further evidence of such a



 series reaction is  that the time to maximum yield decreases as



 the bath temperature increases.  The yields, although lower



 than expected, did  indicate that further experimentation was



 justified.  Moreover, at the end of this series of experimen-



 tation, a better  understanding of the hydrolysis reaction and



 related chemical  analysis was obtained, so that more effort



 could be given to the determination of the reaction model



 itself.



 4.2  Non-Isothermal Analysis Results



     The cellulosic materials used for the acid hydrolysis ex-



 periments were tested quantitatively for their potential sugar



 yields which is an indication of their cellulose content.



 Table 4-1 contains the results of this quantitative sacchari-



 fication.  These yields represent the total experimental poten-



 tial aldohexose content of the sample.  The fermentable aldo-



hexose sugars are glucose,  galactose,  and mannose.   Table 4-2,



 taken from Reference (8),  shows the expected percent composi-



 tion of these sugars in Kraft paper.   The main contribution to



the quantitative sugar yield will come from glucose.   Glucose



can be formed from both amorphous and crystalline cellulose.



Mannose and gelactose are  mainly derived from non-crystalline

-------
                          -32-
                   Table 4-1
         QUANTITATIVE SACCHARIFICATIONS
     SAMPLE
         YIELD
Weight Sugar/Weight Paper %
Ground Kraft Paper
Ground Kraft Paper

Slurried Kraft Paper
Slurried Kraft Paper

Ground Refuse #1
Ground Refuse #1
Ground Refuse #2
Ground Refuse #2
            86
            84

            84.8
            80.5

            38.0
            38.4
            52.6
            52.6
                  Table 4-2
  CARBOHYDRATE COMPOSITION OF KRAFT PAPER PULP
                                              (8)
          Component

  Glucose Galactose

  Mannose/ Arabinose

  Xylose

  Uronic Anahydride
          Percent

            82.4

             7.0

             9.2

             1.4

-------
                           -33-
polysaccharides .  Although the main portion of cellulose in


paper is believed to be in the crystalline form, the exact


amounts of amorphous and crystalline forms are not knc. fin.


     Samples of milled Kraft paper, approximate particle size


2mm, were hydrolyzed with 20 ml of 0.2%, 0.5%, and 1% by weight


sulfuric acid solutions.  The yields and temperature time his-


tories are shown in Appendix II.  Selected samples, quenched


when the temperature reached 180°C, were filtered and reana-


lyzed for their potential sugar yield.  In this manner a hy-


drolysis sugar yield and residual potential sugar yield were


known at 180°C.  These yields were then used as the initial


conditions for the 4-dimensional search outlined in Section 3.3.


Arrhenius '  equation was used to relate the rate constant to the


reaction temperature.  The computer program found in Appendix IV


was used to perform the search which determined the pre-exponential


factors and activation energies that would best fit the data for


the 0.5% acid runs.   It was then assumed that these activation


energies could be used for the 0.2% and 1% acid experiments,


thus only requiring a search on the two pre-exponential para-


meters for this data.  The Arrhenius equations for the calculated


values are:


0.2%      KI  =  1.661 x 1019 * e"AHl/RT


          K2  =  2.21 x 1014 * e-AH2/RT


                          IQ    -AH-i/RT
0.5%      K-L  =  7.59 x 10iy * e   I


          K2  =  2.67 x 1014 * e-AH2/RT
 1%       KI  =  2.95 x 1020 *  e'AHl/RT
          K2  =  5.57 x 1014

-------
                             -34-
with
   hRI  =  45127 cals/g mole
   AH.  =  32800 cals/g mole
     In an acid catalyzed reaction the overall reaction rate is
usually proportional to the acid concentration as well as the
reactant concentration.  Although this would normally result in
second order kinetics, the fact the acid concentration is con-
stant allows the rate constant to be expressed as/
    K..^  = KQ Cm       C = acid concentration Wt. %
where  K.  is the overall constant  K,, K2  shown above.
     Since the reaction activation energies are the same for low
acid concentrations, the acid effect will be contained in the
pre-exponential factors of Arrhenius equations for K., and K2/
P^ = PQCm  where P. is the pre-exponential of K. in
K  = p  e~AHl'RT.  A plot of the log of the pre-exponential
 J»    Jx
factors versus the log of the acid concentration should give
straight lines within the slope of the line.  Figure 4-2 shows
that this relationship held for K,  but not K-.  This result can
be explained, since the actual hydrolysis reaction, K,, is known
to be due to cleavage of the cellulose bonds by the hydronium ion
whereas the decomposition of glucose, K_, is a series of sugar
oxidations which are not simple hydrolysis bond cleavage.
     These results also showed that at zero acid concentration
and high temperatures, 230°C, thermal hydrolysis would occur, but
low yields would result since the ration  K-^/K^ ^; 0.25  is very
small.   This explains why thermal degradation or hydrolysis
occurred in the acid injection system described in Section 3.'3.
     The accuracy of these fitted values was determined by
performing replicate experiments at approximately 230°C.  The
                                                    -4
sum square error of these replicates was  5.362 x 10    with
2 degrees of freedom.  The largest determined curve fit error

-------
5 '
                                           -35-
                                        Figure 4-2
            LOG  (PRE-EXPONENTIAL FACTORS) versus  LOG  (ACID CONC.)
             ©
                          Q/
 J-1.
O.z.
0.3
 0-4  .>

/WT. %)
0-5     0-fe   0.7

-------
                           -36-
            M -3
was 3.3 x 10   with 4 degrees of freedom.  The statistical "F"

ratio is therefore 6.15 which is well within the 19.25 "F"

ratio at the 95% confidence interval.  This test shows that

there is not a significant difference between the fit and the

experimental error.  The actual experimental data points and


the predicted curves are shown in Figure 4=3,  Another qu&§-

tion concerning the accuracy of the experimental data arises

from the ice water quench time.  It was found that approxi-

mately 20 seconds are required to lower the reactor tempera-

ture- from 230°C to 170°C,  This time would appear to con-

tribute a great deal of error at high temperatures and acid

concentration.   Although this assumption would be true if the

reaction continued at the 230°C rate, it is not true when it

is considered that the temperature is continually dropping, as

is the reaction rate.   Using the reaction rates calculated for

a 1% acid solution, a numerical integration was performed for

a linear drop in temperature from 230 to 170°C with an initial

sugar concentration of 11%,  This calculation revealed that

approximately a 11 less ,.:i yield could be expected due co the

quench.  Since the condition used for this test is the most

severe encountered, the error due to quench time was ignored:

     The reliability of the predicted rate constant parameters

can further be demonstrated by their ability to predict yields

with temperature time curves other than those used for deter-

mining them.  Initial runs with the high temperature bath pro-

duced widely different temperature time curves;  this was

found to be due to convection currents established by the

-------
                                    -37-
                        Figure 4-3
               SUGAR YIELD versus  NONISOTHERMAL  TEMPERATURE  (TIME)
 .N   50-
     130
               \QO
                          ioo
ZlO
                               TEMP&
A
51
                            Tir-iE

-------
                             -38-
bath circulation pump.  This problem was remedied by placing



a metal beaker filled with oil in the bath, thus acting as a



buffer between the actual bath convection currents and the test



reactor.  Three of these variable temperature time curves were



used in conjunction with the calculated rate constants to pre-



dict the associated sugar yield curve.  The 'following yields



were obtained in this manner.





                       0.5%  Acid
Curve
I
II
III
Quench
Time
8.6 min.
5.6 min.
6 . 1 min.
Experimental
Yield
0.30
0.24
0.325
Predicted
Yield
0.30
0.21
0.315
It is seen from these results that the agreement between pre-



dicted and experimental yields is very good.



     Since the proposed hydrolysis plant will operate with a



paper slurry, it was necessary to determine whether a signifi-



cant change in rate constants would occur if fibrous material



were used in place of ground particles.  A sample of Kraft paper



was pulped with water in a standard Waring blender.  This sample



was then dried and 0.5 gram samples were prepared from the fi-



brous sheet.  These samples were mixed with 20 ml of 0.5% acid



producing a fibrous slurry which was then hydrolyzed.  The



agreement between predicted and experimental results, Figure 4-4,



indicates that the determined relationship holds for fibrous



samples as well as ground samples.  It is therefore possible



to predict isothermal yields for plant operations using' a pulped



paper slurry.

-------
                         -39-
                  Ficjure  4-4




UGAR YIELD  (KRAFT FIBERS)  versus NONISOTHERMAL TEMPERATURE

-------
                            -40-
     Referring again to Figure 4-3, it is noticed that approxi-



mately 6 to 11% sugar yields were obtained at lower tempera-



tures between 170°C and 180°C.  Saeman's rate constants for



crystalline cellulose indicates that yields of this magnitude,



at low temperatures and short heat up, should not be obtained.




It is believed that the discrepancy aan be explained by the



different regions of cellulose hydrolyzed.  Saeman's original



kinetic data applied to what was called the resistant portion



of cellulose.  He discovered that when working with untreated



ground wood, all plots of residual potential sugar versus time,



extrapolated back to zero time, gave a value for the potential



sugar yield below that obtained experimentally by quantitative



saccharification.  It was believed that the difference between



the original 66.6% potential sugar and the extrapolated 44% at



zero time was due to easily hydrolyz,able amorphous cellulose.



His calculated rate constants, therefore, held only for the



resistant portion of cellulose.  It is believed, from the



hydrolysis of paper results, that it also contains a portion



of easily hydrolyzable cellulose.



     This kinetic study shows that the easily hydrolyzable



portion of cellulose accounts for the sugar yields at lew tem-



perature values and that the kinetic parameters estimated here



are for the residual cellulose.  It is not valid to assume that



these kinetics only apply to residual crystalline cellulose.



Browning     explains that during hydrolysis, cleavage in the



amorphous regions can cause rearrangement and crystallization



of the amorphous cellulose.  The calculated rate constants foi



paper hydrolysis may therefore be a combination of rate contra:.•

-------
                            -41-
 for the amorphous-crystalline cellulose.  The important point



 is that the model was shown to predict the correct yield under



 various hydrolysis conditions.  It is of no great importance



 for the engineering plant design to determine exactly what



 reaction is occurring;  it is important to be able to predict



 the yield under various conditions of hydrolysis.



     The predicted isothermal yields of sugar from paper cellu-



 lose are shown in Figure 4-5.  For these calculations it was



 assumed that 10% of the original potential sugar yield would



 hydrolyze instantaneously.  This value is based on the experi-



 mentally determined sugar yields of 6 to 11% from the easily



 hydrolyzed portion at low temperatures.  This curve gives the



 residence times necessary to obtain maximum yield at various



 temperatures and acid concentration.  If the original potential



 sugar content of the paper refuse is known, this curve will



 give the predicted isothermal yields of sugar.



     The original prediction by Saeman for wood that an in-



 crease in acid concentration and temperature causes an increase



 in overall glucose yield is shown to hold true.   10% yield in-



 crease is shown to occur by doubling the acid concentration at



 230°C and a 10 degree rise in temperature results in approxi-



mately a 5% yield increase.



 4. 3  Experimental Analysis Conclusions



     It was shown by the experimental analysis  that paper
cellulose does hydrolyze to sugar and that the hydrolysis



reaction could be modeled by the  A — L>B — 2_^.c  irreversibl



reaction model used by Saeman.   The reaction rate constants

-------
                  -42-

          Figure  4-5
PREDICTED ISOTHERMAL  SUGARS versus TIME
           -<— ("A")

-------
                            -43-
were found to be different from those calculated by Saeman,



but as predicted, they both increased as temperature and acid



concentration increased, with  Kj_  increasing faster -_han  K2.



The increase of the ratio  K-j_/K2  was not as pronounced as



expected,  and the yield of sugar from paper cellulose at



higher temperatures was therefore lower than that predicted



by Saeman.  Porteous originally predicted a yield of 55% with



Saeman1s data at 230°C whereas the calculated kinetic model



predicted a yield of 41%.  This difference is reaction rates



was thought to be due to the amorphous cellulose content of



paper cellulose.  It was also shown that the predicted



reaction rates held when pulped paper fibers were hydrolyzed.



It was therefore concluded that the calculated kinetics could



be used in the design of a refuse hydrolysis plant under iso-



thermal reaction conditions.

-------
5.  PLANT DESIGN



     The information gained from the hydrolysis experimen-



tation was used in the design of a refuse hydrolysis plant.



As much of the non-cellulosic material as possible must be



separated out of the raw refuse, since additional acid solu-



tion would be required for this useless material.  In addition



to separation, the refuse must be pretr"eated to produce fine



particle sizes which can be hydrolyzed without mass transfer



slowing down the reaction.  Porteous'  preliminary design pre-



treatment system consisted of dry pulverization followed by



flotation separation and secondary shredding.  Although the



heavier metals would be separated out by such a system, the



lighter plastics, bottles, plastic wrappings, rubber, and



any pieces of cut metal entrained in the paper would be car-



ried over to the secondary shredder.  Moreover, secondary



shredding produces particle sizes of approximately one inch



which would result in lower sugar yields due to the lack of



intimate contact of the acid with the paper fibers.  A proven



separation system, used in pretreating waste paper for reuse



as paper pulp, was adapted in place of Porteous1 system.  Al-



most complete separation of the above materials would be ob-



tained and the resulting paper slurry would consist of fine



fibers, the size controlled by the pulper operation, which



were proven to be easily hydrolyzable.



     A continuous flow reactor, as recommended by Porteous,



was incorporated in the design with an additional feature of



a cellulose recycle stream.  The experimental results indicated
                            -44-

-------
                           -45-
 chat approximately  25% of the cellulose would not be hydro-



 lyzed and the recycle stream was used to hydrolyze this resid-



 ual potential sugar  source.  Since the experimental ;
-------
                           -46-
sugar by addition of sulfuric acid and heated water.  Unreacted



cellulose is recycled after flash cooling and liquid separation.



Following acid neutralization, the final operation of concen-



trating the liquors is performed in a feed forward multiple-



effect evaporator system.  The inputs to the hydrolysis plant



are refuse, process water, sulfuric acid, and lime.  The out-



puts from the system are scrap iron, other metals, plastic



inerts, hydrolysis waste, and a concentrated glucose sugar



solution.  A general plant flow sheet is shown in Figure 5-1



through 5-3.



5.1  Separation and Pretreatment System



     The purpose of the separation and pretreatment system is



to eliminate as much of the unhydrolyzable portion of refuse



as possible and convert the refuse to a pulp slurry for the



hydrolysis reactor.  A system which will accomplish this task



is already in existence.  The paper industry employs such a



system to pretreat waste paper for re-use as paper pulp.  This



system is described in reference (12)  and is the basis for the



hydrolysis plant pretreatment process.



     A diagram of the separation system is shown in Figure 5-1.



The incoming raw refuse is stored in a silo storage hopper.  A



ventilation line connects the storage hopper with the direct



fired heater.   A continuous flow of air is drawn from the



storage hopper to the heater, thus eliminating the odor given



off by the raw refuse while in storage.  The storage hopper



feeds the refuse to a magnetic pulley conveyor which rejects



the scrap iron portion of the refuse and feeds the refuse to

-------
                                    -47-
 z
 o

 5


 I
 ai
in
LL

-------
                   -48-
•0
b
a
                                                       UJ

-------
-49-

-------
                          -50-
th e hydropulper.  The hydropulper breaks up the refuse and its
"junker" carries out the larger pieces of unpulped refuse, i.e.
tin cans, plastic bottles, non ferrous metals, and unbroken
glass.  A screen trap follows the hydropulper and eliminates
the plastic films and other lighter pieces of trash.  The
dirt and finer pieces of glass are removed in a cyclona sepa-
rator.  Enough water is added to the hydropulper to produce a
2 to 3% consistency slurry which is the recommended consistency
for such an operation.  The pulp is dewatered in a screw press
to approximately 50% by weight water.  At this point the refuse
is ready for the hydrolysis process.
     It was assumed for calculations that the synthetics, glass,
metal, and inert (rocks, etc.) portion of the refuse will be
separated from the pulp.  This means the pulp will consist of
essentially rubbish (paper, leaves, and wood)  and garbage.  The
pulp quality demands in the paper industry are much more strin-
gent than for the hydrolysis process.  It is therefore believed
that this separation system should be adequate for the hydrol-
ysis process.
Equipment Design Information
  Storage Hopper:
    Standard reinforced concrete.   Design capacity based
    on 3 days storage at approximately 500 Ib/yd .
  Hydropulper System:
    Designed and manufactured by Black Clowson,  Middleton,
    Ohio.  Capacities up to 850 tons/day.  Horsepower
    requirements approximately 20  H.P. day/ton.

-------
                           -51-
 5.2  Hydrolysis Reactor System
     Figure 5-2 is a flow diagram for the hydrolysis reactor
 system.  Freshly pulped refuse is passed from the screw press
 into a series of Moyno pumps which bring the pulp to the de-
 sired reactor pressure.  A stream junction at the inlet to the
 continuous flow reactor mixes the fresh pulp with recycled
 cellulose and enough acid solution to reach the required reac-
 tion temperature, acid concentration, and liquid to solid
 ratio.  The acid is injected into the heated water stream
 prior to the mixing junction.  After passing through the flow
 reactor, the solid-liquid slurry is flash cooled to quench
 the hydrolysis reaction.  Vapor from the flash chamber is used
 as a heat source in the evaporation system.  The remaining
 slurry is separated in a pressurized continuous flow centri-
 fuge.  The liquid continues down stream while the solid stream
 is partially bled of inerts and cellulose before entering a
 series of Moyno pumps which feed the unreacted cellulose into
 the mixing junction as a recycle stream.
     The hydrolysis reactor was chosen from the three standard
 chemical reactors:  batch, continuous stirred tank,  and tubular
 flow reactor.   The operations of charging,  discharging, and
 cleaning of the batch reactor require an exorbitant amount of
 time and material handling which result in high cost for large
 scale operation.   Although well suited for small amounts of
costly reactants,  the batch reactor would be undesirable for
the large amounts of material processed in a hydrolysis plant.
     The continuous stirred tank reactor is not advised for use
         Kl   K2
in an  A	*B 	}C  series reaction,  since the theoretical

-------
                            -52-
maximum batch yield of B (glucose) is unobtainable.  This can
be seen when one realizes that a CSTR is assumed to be well
mixed with outlet reactant concentration equal to the bulk
reactant concentration.  An unreacted stream of  A  is continu-
ously added to the outlet concentration.  Therefore the reac-
tion rate is not proportional to the inlet concentration/ but
to the outlet concentration.  Reference (13) presents a graph-
ical display of the maximum obtainable yield and required
                           Kl    K2
volume of a CSTR for an  A—=•) B —=^ C  consecutive reaction
with variable values of  K-j_ and K2»  It is clearly shown that
a CSTR gives a lower yield of B, and requires a greater volume
to reach its maximum yield than does a plug flow tubular reactor.
     Variations and combinations of batch, semi-^batch, series
CST, reactor configurations are conceivable, but the most simple
and reliable reactor for the hydrolysis reaction would be the
tubular flow reactor with a recycle stream.  Such a reactor with
plug flow will give the high yield of a batch reactor and the
production capacity of a CSTR.
     The design dimensions of the flow reactor will be a func-
tion of required residence time, through-put (fresh and recycle
reactants), degree of axial diffusion (divergence from plug
flow), and the desired flow velocity.  The residence time is
the time to maximum yield of converted sugar.  The residence
time will be determined by the reaction temperature and acid
concentration.  The through-put capacity of the reactor is
governed by the total refuse handling capacity of the plant and
the amount of recycled cellulose.  The size of the recycled
stream is dictated by the amount of incoming unhydrolyzable

-------
                           -53-
 material  and unreacted cellulose.  The desired recycle ratio
 is  ultimately determined from cost considerations.  That  is, as
 ;he recycle stream is increased, the manufacturing anc, initial
 capital cost of the plant will increase as will the product
 rate of sugar.  The final design recycle flow will be chosen
 as  that rate which minimizes the total production cost.
      Divergence from plug flow of the slurry will produce a
 lower expected yield and increase the required capacity of
 the reactor.  A study of the two phase flow'of wood pulp  fibers
 is  found  in References (14, 15, 16).  Such fibers exhibit three
 regions of flow with increase in flow velocity.  The laminar
 region is characterized by a plug flow of fibers surrounded by
 a thin water annulus.  As the velocity increases, the fibers
 begin to break up in what is termed the "transition region".
 This  trend continues until the fibers are completely agitated
 in  a  region of turbulent flow.  The velocity profiles associ-
 ated  with the flow of pulp fibers cannot be described by a
 Newtonian fluid model.  In Newtonian fluids an increase in
 velocity results in blunter velocity profiles, whereas  in the
 case  of pulp,  an increase in fiber flow results in a sharper
 profile.  This tendency toward plug flow at low velocities in-
 creases with an increase in fiber concentration.   It was assumed
 that  such a fiber flow will exist in the hydrolysis reactor.
Therefore, the assumption of plug flow in the reactor will be
valid if the flow velocity is in the range of laminar fiber flow.
The transition velocity will be the limiting velocity which will
produce plug flow.  Although there is no available expression
for calculating this velocity,  it can be obtained empirically

-------
                           -54-
from the curves in Reference  (16) .  The transition velocity



occurs at approximately the same value for a given concen-



tration at various pipe sizes.  For a five percent consistency



slurry the transition velocity is approximately 6 ft/sec.  This ,



velocity is high enough to insure a wide range for the reactor



flow velocity.  Some consideration should be given to sedimen-



tation or settling out of the solids at very low velocities,



but if desired, this effect can be reduced by a vertical flow



reactor.  The optimum velocity will ultimately have to be de-



termined from a pilot plant flow reactor system.



     The material of construction for the reactor must be able



to withstand the corrosive effect of the <1% sulfuric acid so-



lution at temperatures above 400°F.  The selection of a material



for these conditions is hampered by the fact that most corrosion



test data are limited to the boiling point of the acid solution



at atmospheric conditions.  Reference (17)  indicated that the



use of nickel based, nickel containing materials, and high



chromium content stainless steel alloys might be applicable for



such conditions.  Hydrolysis experiments were conducted in



cylinders of Monel , Hastalloy-B, chrome-moly, stainless 316,



and Carpenter 20 alloys.  The hydrolysis in vessels of Carpenter



20 stainless steel gave the highest yield of glucose.  Although



these results did not show a complete study of the corrosion



problem, they did indicate that Carpenter 20 had the best poten-



tial as a material for constructing the flow reactor.  An im-



proved variety of Carpenter 20 designated as No. 20Cb-3 has



been developed.  A corrosion chart for this material, taken



from a Carpenter Steel Co. technical data sheet, is found in



Figure 5-4.   From this chart it can be seen that Carpenter

-------
                                     -55-
                                  Figure 5-4



                        CORROSION RATE OF CARPENTER STEEL

                         No.  20Cb  and  No. 20Cb-3
u.

ul
Ui
 o
o
                                         C°C

-------
                           -56-
20cB-3 exhibits very good corrosion properties in dilute I^SO^



acid at high temperatures.  For design and cost considerations



it is assumed that the reactor will be made of carbon steel



clad with Carpenter 20Cb-3.'  At a rate of 30 mpy/ one inch



cladding would last for twenty years.





Equipment Design Information



Reactor:



  Tubular flow reactor.  Design pressure 500 psi.



  Carpenter 20Cb-3 cladding



  Plug flow at 1 ft/sec



Flash Chamber:



  Assumed residence time for adequate vapor separation of



  2 minutes.  Constructed of Carpenter 20 steel.  Design



  pressure 150 psi.



Acid Storage Tank:



  14 day design capacity.



  Constructed of carbon steel.



Centrifuge:



  Pressurized (150 psi) continuous variety.



  Recommended - Sharpies Super-D-Canter model with continuous



  screw conveyor for solid separation.  Maximum design



  capacity limited to liquid stream of 350 gal/min.



  Horsepower » liquid flow rate.  H.P. ?a gal/min.



  Constructed of Carpenter 20 steel.



  Assumed solid moisture content at discharge of 50%.



Slurry Pumps:



  Recommended Moyno positive displacement.



  Maximum pressure 1000 psi.



  Maximum capacity 500 gal/min.

-------
                            -57-
  Feed pump constructed of steel rotor and housing.



  Recycle pump constructed of Carpenter 20 steel.



Water Pumps:



  Standard steel motorized centrifugal pumps.



Acid Pump:



  Positive displacement controlled volume feed pump.



  Constructed of Carpenter 20 steel.





5.3  Concentration of Sugar Solution and Heat Recovery



     Most processes which use glucose as a raw material require



at least a 6% solution (Torula yeast production) and preferably



a 12% solution (ethanol fermentation) of glucose.  With a liquid



to solid ratio of 20 to 1 the glucose solution leaving the cen-



trifuge will be approximately 2% by weight glucose.  The glucose



solution must therefore be concentrated after leaving the hydrol-



ysis section of the plant.



     An ideal process would perform the required concentrating



while allowing the high temperature stream of water to act as



a preheat or feed for the hydrolysis reactor.  Two relatively



new processes, as cited in a recent Doctorate thesis^ ', which



are being tested for use in concentrating spent sulfite liquor,



perform the task to some degree.  They are reverse osmosis and



electrodialysis.   Reverse osmosis has proven to be effective in



concentrating liquors to 10% by weight solids.  If the sugar



solution contained only glucose, this would be a feasible method



of concentration.  The difficulty is that the hydrolyzed solu-



tion will contain, in addition to glucose,  decomposed sugars



and other large organic molecules from the garbage portion of



the refuse.   Therefore,  the glucose concentration will be

-------
                             -58-
initially 2%, but the total solute concentration may be greater
than 4%.  The upper limit of glucose concentration by reverse
osmosis will be approximately 5% which is below the 12% re-
quired concentration.  Although feasible for the lower limits
of concentration, reverse osmosis, in its present state of de-
velopment, would not ba acceptable for most sugar fermentation
processes.  Electrodialysis has been tested experimentally but
as of yet not proven economically feasible on such separation
processes.  Thus at its state of the art, it cannot be recom-
mended as a means for concentrating the sugar solution.
     One proven means of concentration which will allow partial
use of the high temperature stream as preheat is feed forward
multi-effect evaporation.  The proposed evaporator scheme is
shown in Figure 5-3.  The recommended effects are short tube
vertical evaporators.  They were chosen because of their ability
to be cleaned with a minimum amount of effort.
     The liquid stream from the recycle centrifuge is neutral-
ized  by means of lime addition.  The lime is injected in a
slurry form, using an in-line mixer to insure that complete
neutralization occurs.  The lime,  or CaCo3, reacts with the
sulfuric acid to produce water, CaSQ^, and CC^.  After neu-
tralization the C02 is removed by a gas separation vessel and
the CaSC>4 which precipitates out of solution is separated by
a pressurized centrifuge.  The operation of neutralization
followed by separation is performed to produce a non-corrosive
solution and to decrease scaling in the evaporators.   Lime is
used as the base because of its comparably low cost.   If the
glucose solution will be used for ethanol fermentation, it may

-------
                             -59-
be advisable to use ammonium hydroxide as the neutralizing
agent.  The ammonium sulfate produced by such neutralization
could then be used as a nutrient for fermentation.
     The evaporator system was designed to make maximum use of
the high temperature of the feed stream.  The upper limit of
preheat for the reactor water feed stream is set by the tem-
perature of the flash chamber quench.  This quench temperature
was 177°C  (350°F) since at this temperature the hydrolysis re-
action will be essentially zero.  The latent heat of the vapor
stream from the flash chamber is used to evaporate the product
stream in the first effect and to raise the temperature of the
direct fired heater feed water stream.  It was assumed that the
vapor from the flash chamber would be free enough of impurities
to be condensed directly in the heater water stream, thus elim-
inating a condenser and fresh feed water.  This assumption was
again made for the vapor formed and condensed in each effect.
     The condensate from each effect (other than the last)  is
pumped to the condensing chamber where it is combined with the
flash vapor and make up feed from the last effect's condenser.
This heated stream is passed through the direct fired heater
where it is brought to the required temperature for the hydrol-
ysis reactor.   A bleed off from the preheat stream could be
used to prevent impurities build up if the assumption of clean
vapor is not valid.
     The number of effects used in the evaporation system was
determined by an economic analysis of the evaporator-heater
system.   That is,  for a given initial and final concentration
of sugar,  reactor feed water temperature,  and flash condition,

-------
                           -60-
the optimum use of the potential heat source was made to mini-



mize the required capital investment of the evaporator heater



system and the utility cost of heating oil.  It was found that



for initial and final concentrations of 2 and 12%, the optimum



number of stages would be 6.  This optimum number does not vary



with feed capacity, but it will vary with the degree of concen-



tration necessary.  At 4% to 12% the number of stages was de-



termined to be 5.  This increase in initial concentration would



correspond to a decrease in the hydrolysis liquid to solid ratio.



Six effects were used in the plant design and cost estimates;



this would allow one unit to be used in standby if maintenance



problems develop.



Equipment Design Information



Evaporators:



  Standard vertical-tube evaporators.



  Heat transfer area determined by flow capacity.



  Constructed with cast .iron shell and copper tubes.



Condenser:



  Standard shell and tube construction.



  Cooling flow through tubes.



  Constructed of carbon steel.



  Atmospheric pressure.



Condensing Chamber:



  Volume based on 2 minutes residence  time.



  Standard steel construction.



  Design pressure 150 psi.

-------
                             -61-
Direct Fired Heater:



  Cylindrical construction.



  Carbon steel tubes.



  Design pressure 500 psi.



In Line Mixer:



  Carpenter 20 steel.



  Nettco Flomix  is recommended  (Nettco Corp., Everett, Mass.)



Centrifuge:



  Sharpies Super 0 - Hydrator continuous operation.



  Ordinary steel construction.



  Pressurized at 150 psi.



Pumps - Water:



  Motorized centrifugal pumps



  Carbon steel construction.



Pumps - Slurry:



  Moyno slurry pump.





5.4  Design Calculations



     The basic design calculations were generalized so that a



computer program with variable plant inputs could be written.



The inputs to the program consist of:



  1.  Total plant refuse processed.



  2.  Fractional  input of paper



  3.  Percent cellulose in paper



  4.  Fraction garbage in refuse



  5.  Fraction of refuse separated before hydrolysis



  6.  Fraction of inerts in hydrolysis feed



  7.  Liquid to solid ratio for hydrolysis

-------
                             -62-
   8. Recycle ratio



   9. Acid concentration



  10. Reaction temperature



  11. Time to maximum yield



  12. Chemical yield of glucose.



     The separable portion of refuse was assumed to be that which



can be separated in the hydropulper system  (metals, plastics,



stones, dirt, etc.).  The garbage portion of refuse flows into



the hydrolysis reactor with the paper.  Although the majority



of the garbage, organic plant waste, will be decomposed, it was



assumed that fifty percent would not be hydrolyzed.  This por-



tion would add to the inert portion of the hydrolysis recycle



stream and therefore give a conservative estimate for the re-



actor size and final glucose concentration.  The inert fraction



would include the clay paper additives in addition to the unhy-



drolyzable portion of the garbage.





A. Material Balance  (Appendix IV)



     The following assumptions were made in making the material



balance:



  1)  Specific volume of paper slurry  62.4 lb/ft3



  2)  The liquid content leaving the pre-hydrolysis screw



     press will be 50%.



  3)  66 Be' sulfuric acid (93% H2S04)



  4)  Solid stream from centrifuges will contain 50% moisture.



  5)  Degree of refuse separation described previously in 5.4



  6)  Lime slurry contains 50% liquid.



A computer program print out of a material balance and a gener-



alized flow sheet follows in Table 5-1 and Figure 5-5.

-------
                                -63-


                                Table 5-1

                            MATERIAL BALANCE
                       REPRESENTATIVE 250 TON  PLANT
? 250
INPUT FRACTION PAPER,GARBAGE,SEPARABLES IN WASTE
? .6,.15,.25
INPU1 FRATION CELLULOSE  IN  PAPER
? .8
INPUT TIME TO MAX YIELD  IN  MIN
? 1
INPU'l CELLULOSE FRACTION  CONVERTED AND SUGAR PRODUCED
? .75,.55
INPUT FRACT ACID,SOLID 10 LIQUID.REACTION TEMP CENT
? .004,.1,230
INITIAL FRACTION INERTS  0.28125
INPUT II .INERT RATIO FINAL
? .4
DO YOU WANT MATERIAL FLOW BALANCE YES OR NO
? YES
SEPARATION SYSTEM
SEPARATOR
WASTE
WATER
IN
 250
 12500
OUT T/D
 187.5
 375
IN
 10.4167
 520.833
**************************** ********************
*********************************************
FLASK
WATER
IN T/D
 2173.22
OUT T/D
 1917.73
IN T/KR
 90.551
OUT T/HR
 7.8125
 15.625
REACTOR
CELLULOSE
WATER
ACID
SUGAR
D SUGAR
S INERTS
L INERTS
IN
131 .875
2183.75
9.39247
0
0
52.75
33.75
OUT T/D
32.9687
2173.22
9.39247
79.7844
29.0125
52.75
33.75
IN
5.49479
90.9896
0.391353
0
0
2.19792
1.40625
OUT T/HR
1.3737
90.551
0.391353
3.32435
1.20885
2.19792
1.40625
OUT T/HR
 79.9053
*•****#•(<•#***** ******* ***************-*#****#*******
CENTRIFUGE  #1
CELLULOSE
WATER
ACID
SUGAR
D SUGAR
S INERTS
L INERTS
*******************BLEED  AND
MATERIAL       BLD-T/D
CELLULOSE        21.0937
S INSRTS         33.75
WATER            54.8437
ACID             9 .62221 E-2
PLUS SMALL  AMOUNTS  OF  SUGAR
IN
1.3737
' 79.9053
0.391353
3.32435
1.20885
2.19792
1.40625
LIQUID OUT
0
76.3336
0.385087
3.17657
1.15512
0
1.34374
                               SOLID STREAM
                                1.3737
                                3.57161
                                6.26631 E-3
                                0.147781
                                5.37386 E-2
                                2.19792
                                6.25136 E-2
              RECYCLE*******************
                               TON S/HR
               REC-T/D
                 11.875
                 19.
                 30.875
                 5.41695 E-2
              AND LIQUID INERTS
               BLD-T/HR
                 0.878906
                 1.40625
                 2.28516
                 4.00925 E-3
               REC-T/HR
                 0.494792
                 0.791667
                 1.28646
                 2.25706 E-
*******************************************

-------
                                 -64-
                                                 32*
                      Table  5-1   (Continued)
NEUTRALIZER
WATER
ACID
CASO4
C02
 LIME
SUG^R
D SUGAR
L INERTS
IN T/D
 1841.44
 9.24208
 0
 0
 9.4307
 76.2376
 27.7228
 32.2497
OUT T/D
 1843.14
 0
 12.8257
 4.14951
 0
 76.2376
 27.7228
 32.2497
IN T/HR
 76.7266
 0.385087
 0
 0
 0.392946
 3.17657
 1.15512
 1.34374
****#****#*********«*********«*******************#
OUT T/HR
 76.7973
 0
 0.534406
 0.172896

 3.17657
 1.15512
 1.34374
CENTRIFUGE 2
WATER
CAS04
CO 2
SUGAR
D SUGAR
L INERTS
IN
 76.7973
 0.534406
 4.14951
 3.17657
 1.15512
 1.34374
LIQ OUT
 76.2629
 0
 0
 3.17565
 1.15478
 1.34335
SOL OUT
 0.534406
 0.534406
 0
 9.21027 E-4
 3.34919 E-4
 3.89608 E-4
TONS/HR
*#*#****#*##***#***#********************************

REACT WATER T/HR AT TEMP
 81 .8906 T/HR   244.561 DEC CENT  472.209 DEC  F
TEMP TO HEATER DEC F AND C
                 329.809
                 165.45
EVAPORATORS
STEAM FROM FLASH USED 2.9652 TONS/HR
EFFECT         VAPOR          TONS/HR
 1              4.86472
 2              6 . 58 32 7
 3              7.98176
 4              9.1766
 5              10.0442
 6              10.9322

-------
s-s
         .ILJ" ."f T1

-------
                            -66-
B. Reactor Design and Recycle Calculation



     The design of the reactor vessel is determined by the flow



capacity, flow velocity, and required residence time.  The total



flow through the reactor is found by a recycle material balance



on the reactor system.



     The recycle calculation is performed on the solid portion



of the refuse.  It is only necessary to consider the cellulose



and inert portion of the stream.  The soluble portion of non-



cellulosic materials and liquid will be separated by the con-



tinuous centrifuge and therefore will not be included in the



recycle loop.



  Let ( C^  =  fresh feed of cellulose  Tons/hr



       Ij_  =  fresh feed of inerts  Tons/hr



       C2  =  recycled cellulose  Tons/hr



       R,  =  entering ratio of inerts to cellulose



       R2  =  exit ratio of inerts to cellulose



        B  =  amount of cellulose bled off  Tons/hr



        Y  =  fractional conversion of cellulose



       YI  =  fraction yield of sugar



The final ratio of inerts to cellulose at the exit of the



reactor will be:



           Rj_ (C^ + C2)     R^
     ^     Y (CI + C2)    Y




At steady state the amount of inerts entering the reactor will



equal the amount of inerts bled off.



    1^  =  R2-B



A material balance around the bleed point requires that the

-------
                               -67-
   (1 - Y) (C1 + C2)   =   (C2  +  B)




           B -  (l-Y)Ci
    C   =  	-

     *         Y




     Thus once values  for R^  and   Y   are  set the total amount



of cellulose and  inerts  in  the reactor  can be determined.



     The total amount  of solid material in the reactor will in-



clude, in addition to  the cellulose and inerts,  the non-hydro-



lyzable portion of garbage  (G).  Total  solids will  be:


     S__  f+ i^ f\  _L  f^   ,i  TJ  / f^   i_ ^ \         •
     *~  o i WT T  v* o  *  *»T VNO "• >* o /
             Ju    *•    J. a.    t»





From the solid to liquid ratio, L, the  necessary liquid flow rate



is found to be  W =  LxS  and  the total  weight of material  will



be  M = S + W Tons/hr.   With  the assumed  value of 62.4 lb/ft3



the total volumetric flow rate can be determined (Q).   This



value in conjunction with the residence time   T   determine the



reactor volume,   V = QxT.  The necessary  cross sectional area



and length can be found  from this volumetric  flow,  residence



time, and flow velocity  of 1 ft/sec.



C. Energy Balance



     The heat load to the system is a function of plant capacity,



liquid to solid ratio, recycle ratio, reaction temperature,  and



preheated feed water temperature.  The  first  three  of  these are



directly associated  with the required liquid  flow stream in the



reactor (W) .   The temperature of this stream  (T-^) is set by the



reaction temperature.  The preheat temperature  (T2)  is  calcu-



lated by an energy balance on the flash and evaporator  section.



          V.       6   Tj:^ + FT£

   T2  =  -J-  +  E
                       \  c  + F

                      01  e

-------
                            -68-
Where   V  =  vapor from flash chamber, Ib/hr




        X  =  latent heat of vapor, BTu/lb.




        W  =  water flow rate to reactor,  Ib/hr


                               T3 rn. •,

       C   =  heat capacity, 1
       T   =  temperature from effect  e  °F



       C   =  condensate from effect e  —

        e                              nr


       T   =  make up feed temperature  °F



        F  =  make up feed flow Ib/hr



The required heat load to the system will then be




   Q  =   (Tx - T2)WCp



This is supplied by the direct fired heater with oil at



1.5E5 —=-y  with 80% conversion efficiency.






D. Flash Chamber Design



     The amount of material vaporized in  the flash chamber  can



be determined by an adiabatic enthalpy balance where:  The



enthalpy of the feed equals the combined  enthalpy of the vapor



and liquid stream leaving the chamber.






   F HL  =  V HV  +  L HL     enthalpy balance
      i        o        o




      F  =  V + L             mass balance



   F HL  =  V H^  + (F - V)H^
      j_        o            o



            H^ - HL


      =•  =  —	r           fraction flashed
      £     -rrV   TjJ-l
            il    Jtl_
             o    o



For a flash from 230°C to 177°C




   »  =  0.117




     The size of the flash chamber is determined by the cross

-------
                           -69-
                                               (19)
of the chamber is usually between 7 and 12 ft.     r to prevent



splashing and therefore liquid entrainment.  The allowable vapor


                      2
flow rate (G) Ib/hr.ft   is determined by an empirical correla-



tion based on a decontamination factor,  DF = weight vapor/



weight of entrained liquid.  From Reference  (20) the recom-



mended flow rate for DF » 10/000 at 300°F is 200 Ib/hr.ft2.



The recommended flash temperature is 350°F, therefore it is


                                                         (19)
necessary to use the empirical correlation found in Perry
             ,1
        G = (T   'P  (P£ - Pg)



With   G  =  Ib/hr.ft2 of vapor



      p   =  vapor density lb/ft3 at flash temp.



      p^  =  liquid density lb/ft3 at flash temp.



      C1  =  empirically correlated factor



      C1  =  80 at  DF of 10,000



For  T  =  350°F



     G  =  320 Ib/hr.ft2



For a total flow rate of 2 x 10  Ib/hr the cross sectional area


                 2                                3
required is 69 ft  and the total volume is 8300 ft .   This volume



will result in a vapor residence time of  2:0.7 minutes.  For the



computer program a residence time of 2 minutes was used to cal-



culate a nominal flash chamber volume.  This will give a con-



servative estimate of the volume required for the preliminary



design.



E. Evaporator Design



     The design procedure for feed forward multi-effect evapo-


                                  (21)
ration systems was taken from Kern    .   In such a design the



temperatures and pressures in the first and last effects are



fixed.  It is usually assumed that equal areas will be used and

-------
                            -70-
that under such conditions the pressure difference between

effects will be approximately equal.  The.equal area restric-

tion is imposed, partially, because it is less expensive to

build a system with equal area effects.  From these pressures

the saturated liquid temperature can be found.  The actual tem-

perature and pressure drop in the system will adjust itself

during operation according to the actual heat transfer coef-

ficient in each stage.  The steam supply for the first effect

is taken from the flash chamber and the vapor formed in each

effect is used to evaporate the liquor in the subsequent effect.

This liquor will boil at a lower temperature than the condens-

ing vapor because its saturation pressure is lower than the

vapor's, due to the staged pressure drop.

     The steam and surface requirements for the multi-effect

evaporation system are computed by performing a heat balance

across each effect and an overall material balance on the system.

  WSX + WfCf(Tf-T1)   =  W-^             Heat balance 1st effect

                  i
  W-  -,\- -,  + (w:=- Z Wn)  C._i (T-  -,-T.)  = W.X.    Heat balance on
   i-l x-1     f n=1 n   3.-1  1-1  J     x x   subsequent effects
         TT
  E  =   z, W_                           Material balance
        n=l  n

  A   =  wsxs
   1     u-(T -T )                        Required surface area
where  Cf  =  specific heat of feed BTu/lb°P

       TF  =  feed temperature °F

       WF  =  feed Ib/hr

       TS  =  saturation temperature of steam °F

-------
                             -71-
       W   =  steam to first effect Ib/hr
        O
        E  =  total required evaporation  Ib/hr
       C.  =  specific heat of liquor in effect i  BT,/lb°F
       T.  =  boiling point of liquor in effect i  °F
       W^  =  vapor removed in effect i  Ib/hr
       A£  a  latent heat o£ vapor i  BTu/lb
       A-  =  area of effect i  ft^
       U.  =  heat transfer coefficient for effect i BTu/hr.ft2  °F
     Therefore for a system composed of  K  effects there will
be K + 1  unknowns, the required steam input and K vapor rates,
and K + 1  equations.  These equations were solved by matrix
inversion in a variable input computer program.  If the areas
are not equal the pressure drops, and therefore temperature dif-
ferences,  are adjusted until they are equal.
     It was assumed that the boiling point rise due to solute
content will be negligible.  This assumption was based on infor-
                         (21}
mation obtained from Kern v  '  which indicated that over the
range of 0 to 20°Brix (£? % weight sugar)  the.BPR was approxi-
mately 1°.  It was further assumed that the specific heat of
the solution would be 1 BTu/lb°F.  Over the same range of con-
centration  C_  varies from 1 to 0.9.
             £T
     The heat transfer coefficient in each stage will be con-
trolled by the temperature, temperature difference,  the viscosity
of the liquor, and scale formation in the effect.   The standard
method of calculating an overall heat transfer coefficient from
the individual resistances is  not used in practice.   Most in-
formation concerning the heat  transfer coefficients  is obtained
from operating experience with the given  type of effects.

-------
                             -72-
Reference  (19) gives a range of experimental values for ver-



tical tube evaporation with natural water circulation of 200 -



500 BTu/hr.ft2°F.  Kerr^19) gives data for operational transfer



coefficients obtained with a feed forward system used in concen-



trating cane sugar to 50° Brix.  The transfer coefficients are



from 100 to 450 over a temperature range of 220 to 120°P.


    (21)
Kern   ' also presents data for concentrating cane sugars from



approximately 13 to 50°Brix with AT=23°F and a temperature range



of 274 to 180°F.



     The proposed system for concentrating the hydrolysis sugars



operates with a AT2?23°F, temperatures from 350 to 212°F, and



sugar concentrations from 2 to 12%.  Since other solids will be



mixed with the sugars, the actual concentrations will be from



approximately 4 to 24%.   Given the previously mentioned experi-



mental data and the above specifications, a range of coefficients



from 500 to 250 was used in the design calculations.  The data



in Table 5-2 were used in the design of the multi-effect system.

-------
                 -73-
       Table 5-2




EVAPORATOR DESIGN DATA
Steam Press,
Chest psia

1
2
3
4
5
6
To CONDENSER

135
100
74
57
35
25
14.7
Temp F6

350
327
304
282
260
240
212
L,
BTu/lb

870
889
905
924
939
952
970
U' o
BTu/hr ft2

500
480
450
410
370
250
500

-------
 6.  PLANT ECONOMICS





     Many of the design parameters for plant operation cannot



 be determined without an economic evaluation of the hydrolysis



 plant.  That is, variables such as recycle rate, acid concen-



 tration, reaction temperature, and residence time must be set



 such that the manufacturing cost of glucose is minimized.  A



 knowledge of the effect of total refuse input and its compo-



 sition on the manufacturing cost must also be determined, be-



 fore a decision can be made concerning the economic potential



 of refuse disposal by paper hydrolysis.  It would require a



 great amount of labor to perform an overall economic analysis



 such as this, without the use of a plant-simulating computer



 program.



     The previously described generalized material flow program



 (Section 5.4) generates the information necessary to size the



 individual plant components.   The size of each component can



 then be used to determine its purchased and installed cost.  From



 these costs, the total fixed capital investment is calculated.



 The material balance is also used to determine the total manufac-



 turing cost per pound of glucose.



 6.1  Capital Costing Procedure  (Appendix IV)



     Estimates of equipment costs, not including the hydropulper



 system, were taken from a recent article by C.E. Guthrie^2^.



 The equipment cost information in this article included, in ad-



 dition to purchase costs, the size exponential factor for each



piece of equipment and a direct material and labor factor used



to determine the total installed cost.  The M & L factor includes:
                              -74-

-------
                           -75-
 piping,  concrete,  steel,  instruments, electric material,  insu-

 lation,  paint,  and labor  necessary to install the  component.

 The  hydropulper system  cost was  estimated by the Black  Clawson

 Co.  for  an  80 ton/day capacity system with an 0.6  factor  for

 scale-up.   The  cost information  in Reference  (22)  was for mid-

 1968 and a  6% escalation  was used to predict the capital  invest-

 ment for mid-1969.

      To  arrive  at  a value for the final fixed capital invest-

 ment,  a  percentage of the installed equipment cost was  used to

 determine the additional  plant cost.

         Building Cost = 20% of IEC (Installed Equipment Cost)
          Outdoor-indoor  type construction

         Freight &  Taxes = 8% of  IEC

         Construction = 17.8% of  IEC

         Engineering  = 10% of IEC

         Contingency  & Contractor Fee = 18% of Direct Plant Cost

         Working Capital = 15% of Direct Plant Cost

The  above percentages were taken from Reference (23)  and are

accepted values used in preliminary cost estimations.

     A printout of the equipment sizes and cost for a nominal

250  ton  plant are  shown in Figure 6-1.  The manufacturing costs

in this  example represent 24 hours of continuous operation.

Given any set of initial conditions for plant operation, the

computer program will calculate the presented information.  In

this manner, it is possible to determine the total manufacturing

cost per pound of sugar for any municipality with its own local

plant operating cost and refuse composition,  'in order to use

this program to evaluate a plant for  any location,  see Appendix IV.

-------
                                 -76-
                             Figure 6-1

                CAPITAL & MANUFACTURING  COST ANALYSIS
                    REPRESENTATIVE 250 TON PLANT	
                                                                    r
DO YOU WANT EQUIPMENT  SIZE  AND  COST YES OR
? YES
*>*******CQST ANALYSIS*******************
EQUIPMENT
HOPPER
CONVEYOR
KYPROPULP
RFACTOR
;>CID STORAGE
FLASH CHAM
CENT 1
NrUT
LIME ST
CENT 1
HEATER
OIL ST
EVAP
CCND
COND POT

PUMP
           NO
SIZE
27000
100
250
47.6612
121078.
97.2111
283.956
304.302
2218.99
304.302
2.33224 E+7
43900.9
1521.98
1291.5
87.49
FT" 3/KR
500.801
12019.2
751.202
6.85696
412.326
937.577
, 18.4916

FT" 3
FT
TONS/DAY
FT" 3
GAL
FT" 3
GAL/MIN
GAL/MIN
FT" 3
GAL/MIN
BTU/HR
GAL
FT" 2
FT" 2
FT" 3
H.P.
2.73062
65.5349
27. 3062
0.311563
14.9881
34.0809
0.168042
P COST
9732.57
9978.68
133363.
9089.98
5668.84
10461.5
79387.6
3711.69
1026.93
17643.9
74047.6
8939.09
349953.
10628.1 •
3101.27
P.C.
1190.92
6217.17
3943.51
660.805
2013.16
4425.2
279.412
IN COST
10705.8
16165. 5
213381.
13332.
10487.4
13782.6
127020.
5938.7
1129.62
28230.2
120698.
16537.3
664911.
24869.7
6202.53
i.e.
2870.12
14983.4
9503.86
1592.54
4851.72
10664.7
673.382
TOTAL PURCHASED  EQUUIPMENT COST 790192. DOLLARS
10TAL INSTALLED  EQUIPMENT COST 1.39764 E+6 DOLLARS
BUILDING COST
FREIGHT AND TAXES
CONSTRUCTION COST
ENGINEERING COST
279529. DOLLARS
111811. DOLLARS
248781. DOLLARS
139764. DOLLARS
DIRECT PLANT  COST                2.17753 E+6 DOLLARS
CONTINGENCY AND  CONTRACTOR FEE  391955. DOLLARS
 FIXED  CAPITAL INVESTMENT

 WORKING  CAPITAL
2.56948 E+6 DOLLARS

385423. DOLLARS
                            (continued)

-------
                                -77-
                        Figure 6-1   (continued)
•****************MANUFACTURING  COST********************
INPUT DUMPING FEE PER TON
? *
input cost for disposal  of  waste per ton
? 3
INPU1 INTEREST RATE AND  YEARS  OF OPERATION
? .04,20
RAW MATRIALS
ACID            9.24208        TONS/DAY
LIME            9.4307         TONS/DAY
UTILITIES
WATER           150902.        GALS
ELECT           12984.3        KILOWATTS
                4390.09        gal
                86.0937        TONS/DAY
                72             ERS
                24             HRS
oil
WASTE DISPOSAL
LA BOR
SUPER
FRIN3E BEN
MAINTAIN        0
SUPPLIES        0
FIXED CHARGES
TAXES           0
INSURANCE       0
cap return
GENERAL COST
PAY OVER        0
LAB             0
PLANT OVER      0

TONS /DAY OF GLUCOSE  75.7071
TOTAL COST/DAY NO DUMP FEE

COST/TON OF GLUCOSE NO DUMP
COST/LB OF GLUCOSE NO DUMP

TOTAL COST/DAY WITH DUMP  FEE
COST/TON WITH DUMP FEE
COST/LB WITH DUMP FEE

TIME : 6.365 SEC.
READY
                                0
                                0

                                0
                                0
                                0
                                0
                                0
295.747
113.168

37.7256
162.303
439.009
258.281
216
84
45.
356.873
26.7655

142.749
71.3745
603.964

71.7655
71.7655
239.218
                               3235.71 DOLLARS

                              42.7398 DOLLARS
                               2.13699 E-2 DOLLARS

                               2235.71 DOLLARS
                               29.531 DOLLARS
                               1.47655 E-2 DOLLARS

-------
                          -78-                               .  y;







6.2  Manufacturing Cost Estimation






     The amount of raw material required for a given plant size



is calculated from the material balance.  The raw materials



purchase prices were taken from a June 16, 1969 edition of the



Oil, Paint and Drug Report in which the current prices f.o.b.



New York are given for all major chemicals.



     Utility costs were calculated from rates given in Ref.  (24)



for 1967.  These rates will vary with the given plant location.



Mid-range values were used for calculation purposes.



     Labor costs were based on three men operating the equip-



ment with one supervisor, and three shifts.  This amounts to



one man per plant section with one overall supervisor.  Labor



rates are reported in U.S. Department of Labor publications and



a yearly index for such rates is given in Reference (24).



     Other direct costs such as fringe benefits,  maintenance,



and repairs are calculated on a percentage basis, as are the



indirect costs of payroll overhead, laboratory and plant over-



head.   These percentages were taken from References (23)  and (24),



     The fixed charges such as capital return, taxes,  and insur-



ance are all based on the fixed capital investment.  The charges



for the original capital investment depend upon the source of



the capital investment.  It was assumed that these charges would



be 4% for 20 years if the plant is built by the municipality,



and 10% for 20 years if by private industry.  From these interest



rates and years of operation an overall capital recovery factor



can be determined.  The taxes and insurance are a percentage of



the fixed capital investment.  Table 6-1 gives the values used



for calculating the direct,  indirect,  and fixed cost of manu-



facturing.

-------
                              -79-
                           Table 6-1



                     MANUFACTURING COST ANALYSIS
Direct Cost
   Raw Materials



     H2S04  66%



     CAC03



   Utilities



     Oil



     Water



     Electricity



   Labor



     3 Laborers



     Supervisor



   Maintenance (Materials & Labor)



   Supplies



   Fringe Benefits
$32.30/ton



$13.50/ton








$ 0.10/gal.



$0.25/1000 gal.



$0.010/KWHR







$3.00/hr.



$3.50/hr.



       5% of F.C.I.



      13% of Maintenance Material



      15% of Labor Cost
Indirect Cost



   Payroll Overhead



   Laboratory



   Plant Overhead





Fixed Charges



   Capital Investment



     Municipal



     Private



     Taxes



     Insurance
15% of Total Labor Cost



15% of Total Labor Cost



50% of Total Labor
 4%, 20 years



10%, 20 years



 2% of FCI



 1% of FCI

-------
                              -80-
     In addition to these operating costs there will be the



cost of disposing of unhydrolyzed waste from the plant and pos-



sible credit for disposing of the original waste.  The charge



for disposing of plant waste will be lower than that associ-



ated with raw refuse disposal since it is compact and already



separated.  For calculation purposes/ it will be assumed to cost



$3.00; approximately the lower limit of incineration cost.  A



dumping fee of $4.00 was used to demonstrate the effect of waste



disposal credit on the total manufacturing cost.  As stated



earlier, the dumping fee is the charge for waste disposal assigned



to the municipality by the plant.  It can vary from zero to a



value which is just under the cost of the next best means of



disposal.



6.3  Manufacturing Cost Analysis



     The operational plant variables such as temperature, acid



concentration, liquid to solid ratio, and recycle ratio, must



be set such that the sugar manufacturing cost is minimized.  The



reaction temperature and acid concentration effect on sugar cost



are independent of the recycle ratio but not the liquid to solid



ratio.  If a lower liquid to solid ratio is used, then an in-



crease in acid concentration will not increase the total acid



cost as appreciably as it would at a higher ratio.  It is not



possible to determine what the lowest feasible liquid to solid



ratio is without data from a flow reactor experimental apparatus.


                                 (26)
It has been shown by Saeman et alv  ;that values as low as 3 to 1



produce consistent hydrolysis yields.   The hydrolysis plant



relies on thorough mixing of the pre-pulped cellulosic material



and acid solution prior to passage through the flow reactor.



Due to such consideration, a middle range value of 10 to 1 was

-------
                           -81-





chosen for the liquid to solid ratio.  A study of the acid



concentration and temperature effects on the operating cost was



conducted for a hypothetical 250 ton plant with 40 and * 0%



paper contents.  The cellulose content of paper (amorphous and



crystalline) was set at 80%.  The expected sugar yields were



taken from the experimental analysis section of this report.



     A study of the sugar manufacturing price was performed for



ranges of temperature from 220 - 240°C and acid concentrations



of 0.2 to 1%.  It is believed that extrapolating yields for



acid concentrations outside of this range would not be possible.



Not enough information concerning the exact effect of the acid



catalysis on yield is known to allow this.  Above 240°C the



reaction residence time is below 10 seconds.  Such short resi-



dence times give little margin for process control and it would



be unrealistic to consider such conditions for plant operation.



The manufacturing costs for the conditions considered are pre-



sented in Table 6-2.  These costs range from 8.5 to 2.7C/lb.



The costs with a dumping fee credit of $4.00 range from 7.3 to



2 cents/lb.   The lowest cost occurs at a 1% acid concentration



and a 230°C reaction temperature.



     The optimum recycle rate for these, 230°C, 1% and 60% paper,



was found to be a 0.4 ratio of inerts to cellulose in the reactor,



A range of 0.3 to 1 was studied and minimum cost occurred at 0.4.



The optimum recycle setting varies with reaction conditions,



yield,  L/S ratio, and plant capacity.  It would therefore be



impossible to set a value which would be optimal for any given



hydrolysis plant.

-------
                     -82-
                Table 6-2
EFFECT OF ACID CONCENTRATION AND
TEMPERATURE ON MANUFACTURING COST
COST 0 lb,
Acid
% Paper Concentration
40 .2
60 .2
40 .5
60 .5
40 1.
60 1.
Temperature °C
220° 230° 240°
8.5«
6.0
5.0
3.7
• 4.8
3.3
7.4« 6.2$
5.4 4.4
4.7 4.3
3.2 2.8
4.2 *
2.7 *
*Not feasible (reaction time too short)

-------
                             -83-                             ' ,-






      The effect  of  overall plant capacity on the manufacturing



 cost of  sugar was studied for various refuse compositions.



 Table 1-2 demonstrated  that  a wide range of municipal  refuse



 compositions can be expected.  Three different refuse  jompo-



 sitions:   40% paper,  30% garbage, 30% separables;  50% paper,



 17%  garbage, 33% separables;  60% paper, 15% garbage,  25%  sep-



 arables,  all with paper containing 75% cellulose, were used to



 determine the manufacturing  cost/lb. sugar.  In this manner the



 expected cost can easily be  determined for the various types of



 communities.  A  basis of 5 Ib. of refuse per capita per day



 was  used in calculating population from total plant capacity.



 Figure 6-2 presents this calculation and Figure 6-3 shows  the



 approximate fixed capital investment for such plants.  Opera-



 tional variables used in these calculations were 230°C, 1%



 acid, and a 10 to 1 liquid to solid ratio.  Although the re-



 cycle ratio was  not optimized for each plant size, it was held



 in a  suboptimum  range.  In this range the recycle ratio had



 little effect on total cost and was close to the actual optimum



value.



     Figure 6-2  also shows the range of sugar cost which would



result from using blackstrap molasses as a raw material for a



fermentation process.  Blackstrap molasses is the waste syrup



from a sugar cane crystallization process.  It is the most



widely used fermentation raw material and therefore would be the



most competitive sugar containing raw material.   Blackstrap



molasses contains approximately 55% sugar by weight including



sucrose,  glucose, and fructose.   Since this molasses is an



agricultural commodity,  its  selling price fluctuates a great

-------
                                -84-
                              Figure £-2

                   SUGAR COST .versus PLANT CAPACITY,
/•>
 h
 3
 M
 V
ov.
Z'dL
5 1
3 .§
G-3
a
ii
                                        40V. MsPEfc CONTBHT
                                          CO*Tfi VWITMCJUT PUMI*
                                                                         OP
                                                                   COtt Of
                       PLANT CAPACITY CT&NS WASTE/DAY]
     o
     H

                   \co
 aoo
-4 - 1
                                                300
                                            1 - 1 - 1 —
                                                              iooo
   400
-4	1
                      CORR.ESPONPIN& POPULATION  SOURCE (xlO )

-------
                  -85-
             Figure 6-3
CAPITAL COST versus PLANT CAPACITY

-------
                          -86-
                                    (21\
 deal.  The Commodity Year 1968 Book     gives the selling price
 for molasses up to February 1968/ and the ranges for 1966/ 1967,
 and 1968 are 11 to 12, 17 to 18.75, and 17 cents/gallon.  This
 fluctuation in selling price greatly affects the ability of a
 process to produce a fermentation product at a constant market
 price, which ia on© of the main reasons for the §witch from fer-
 mentation to synthetic production of many products.  Hydrolysis
 of refuse would produce sugar at a more constant cost and over
 the years the actual production price should' decrease, since
 the trend is toward a higher level of refuse paper composition.
 The main advantage of using molasses is its high sugar concen-
 tration which allows it to be used for any fermentation process,
 with economical shipment of the raw material over long distances.
     Plants which operate at cost below that of molasses can be
 considered as producing a saleable raw material.  It is noticed
 that in some cases it would be necessary to charge a credit for
 the refuse processed to operate in a competitive range.  In the
 case of a municipality this would require absorbing some of the
 cost of production.  If the necessary charges are below the
 existing cost of waste disposal, then it would be of an economic
 advantage to build a hydrolysis plant.  If the plant is owned
 by a private industry then it would require that the plant
 charge the community a set cost for disposing of its refuse.
     The quoted prices given in the graph are for a capital
 return factor based on 4% interest for 20 years.  If owned
privately,  a factor of 10% for 20 years would have to be used.
With this value the cost per pound increases approximately
 0.2 cents/lb.   Another factor which is not shown in this graph

-------
                            -87-
 is  the  liquid  to  solid ratio  effect.  A 10 to 1 ratio was used



 for the calculations but this  is not necessarily the lowest



 possible ratio.   It was found  for a 500 ton plant operating



 with 50% paper that, at a 7 to 1 ratio, the manufacturing price



 drops from  2.8 cents/lb. to 2  cents per Ib., and correspondingly



 an  increase to 13  to 1 increases the cost to 3.4 eente/lb,  This



 points  out  the dramatic effect the liquid to solid ratio has on



 overall production cost.



      For the conditions used,  it is therefore shown that the



 following plants could produce a 12% aldohexose solution which



 would be competitive with molasses on a cost/lb. sugar basis:



 a 40% paper composition would  reach the competitive range at



 400  tons with  a dumping charge;  a 50% paper composition would



 be  competitive at  the 400 ton  level without a dumping charge



 and  at  the  200 ton capacity with a dumping charge;  a 60%



 paper composition  would be competitive at the 200 ton level



 with  no  dumping fee and the 100 ton level with a dumping fee.



 The minimum expected costs at  1000 tons capacity,  60% paper,



 with  and without a dumping credit, are 2 and 1.3 cents/lb.



 respectively.  These values are well below the average cost



 associated with molasses of ~2.5 cents/lb. of sugar.



      The  lowest predicted disposal price for the most economical



 incineration process is approximately $3.00/ton, presently



 ~$4.00/ton.   Although sanitary landfill can undercut this cost



 in some areas,  there are many cities which have no available



 close land sites which enable them to even approach $3..00/ton.



 In such municipalities,  with refuse paper contents greater than



 50%, refuse hydrolysis would be a means to cut disposal cost and



produce sugar at a competitive market price with molasses.

-------
                            -88-
 6.4  The Marketability of a Glucose Solution



     It is assumed that the sugars produced by the hydrolysis



 are fermentable.  This seems to be a valid assumption since the



 aldohexose sugars of glucose and mannose, which are produced,



 are the same sugars used in most fermentation processes.  It


                                    (28}
 has also been proven by Saeman et alv  '  that these same sugars



 obtained by wood hydrolysis are fermentable.  In some cases



 contamination of the fermentation product occurs, such as by



 the S02 in spent sulfite liquors.  Such difficulties are not



 foreseen with the hydrolysis plant product which, in addition



 to being free of such inorganics as SO^,  should be free of micro



 organism contamination due to the high temperatures of the



 reaction.



     The total U.S. consumption of blackstrap molasses in 1967



was 700 million gallons.  Approximately 300 million gallons were



used in the industrial production of drugs, citric acid, vinegar,



and ethanol.  This indicates that approximately one million tons



of such sugars were consumed in processes which could equally



as well use the product of a hydrolysis plant.  This does not



necessarily mean that a greater market is not available for the



raw sugar solution produced by hydrolysis,  since at a lower



price than molasses,  this product may reopen the markets that



have since been closed by synthetic processes.  The main draw-



back to producing sugar solutions by hydrolysis is the low



concentrations produced.  That is,  at concentrations of 10 to



15% (molasses is approximately 55%)  the cost of shipment to



distant areas may preclude its ability to compete with molasses



prices.  Consideration must therefore be  given to building a

-------
                               -89-
plant, which uses the hydrolysis plant product as a raw material,



in conjunction with the hydrolysis plant.  The construction of



a fully integrated source and consumption plant has t le advan-



tage of cutting the overall cost of production for both the rav;



sugar and the final product of ethanol, citric acid, etc.  The



construction of such a plant with the final product of ethanol



was suggested by Porteous.



     Ethanol or ethyl alcohol was originally totally produced



by fermentation of molasses, but as of 1954, synthetic processes



using ethylene hydrolysis and hydration began to replace fermen-



tation.  Presently the only large fermentation plant in exis-



tence is operated by Publicker Industries, Philadelphia, Pa.



This change of processes was due to the variable price of black-



strap molasses and the low price of ethylene.  Of the possible



products which can be produced by fermentation, ethanol has the



largest available market;  approximately 520 million gallons



were produced in 1963.   As of June 16, 1969, ethanol was selling



at $0.52/gallon.  There are a myriad of uses for ethanol as



both a raw material and as a solvent.  If the selling price



were reduced, there would most likely be a much larger demand



for ethanol.



     Browning'°' states that sugar must be produced at approxi-



mately one-third the 'cost of ethylene before fermentation would



be competitive with synthetic ethanol production.   This applies



to the production of ethanol by private industry where a margin



of profit is expected.   Using the current selling prices of



ethylene,  3.25£/lb.,  this requires that sugar be produced at



1.08C.   Even with a dumping fee of $4.00,  the lowest predicted

-------
                             -90-
sugar cost is 1.3$.  This stringent requirement indicates that



it would be very difficult to persuade a private concern to



build and operate an ethanol producing refuse disposal plant



under the present cost considerations.  It should be kept in



mind that these costs are based on the current knowledge of



the system, and that a decrease in cost could result if it Wefe



found that a flow reactor could operate at a lower liquid to



solid ratio.  It is believed that if a municipality were will-



ing to build and operate an ethanol plant, it could dispose of



its refuse without charge.  Since such a plant would not have



to operate at a profit, its sole manufacturing criterion would



be to produce ethanol at the break-even point.  This would re-



quire that the municipality enter the chemical sales field but



this factor should not dissuade the municipality from such an



advantageous means of refuse disposal.



     An estimate of the ethanol manufacturing cost can be ob-



tained by a cost analysis performed on the raw material required


                           (29)
for 1000 gallons of ethanol    ,  ana an updated investment cost



per unit of capacity.  The cost associated with the sulfuric



acid used to adjust the pH is excluded, since the pH can be



fixed by the degree of neutralization in the hydrolysis plant.



Since ethanol production by fermentation is a dying art, the



latest capital cost per year capacity was $78 in 1950.  This



value is presumably high, since in most cases^30'  the actual



cost increase over such a long period of time is below that



indicated by cost indexing methods.   This smaller increase is



primarily due to the technological advancements in the manufac-



ture of process equipment and materials.  A value of $100/ton

-------
 year would  be  considered more realistic.  Using this value,
 the indirect and direct cost of manufacturing are calculated
 on a percentage basis  as indicated in Section 6.1.  Table  6-3
 contains  the ethanol by fermentation cost estimation.
      The  manufacturing price of ethanol is calculated as
 $0.52/gallon.  This result implies that ethanol could be pro-
 duced at  a  value equal to the existing selling price.  There-
 fore for  a  500 ton plant with 50% paper, ethanol production
 would be  an economical use for the refuse produced sugars.  It
 is also seen from these results why private industry would not
 be willing  to  enter the hydrolysis-ethanol industry with the
 predicted sugar cost.  The overall capital cost for a 500 ton
 hydrolysis  plant and a 5.4 million gallons ethanol plant would
 be 5.2 million dollars.  The expected profit before taxes with
 a  $4.00 disposal charge would be 8.4 hundred thousand dollars,
 which is  only a 16% return on the original investment.  The
 fixed manufacturing cost included a capital recovery factor
 which calculated both  the yearly cost necessary to recover the
 original  capital investment and an interest charge of 4% per
 year;  therefore all calculated percentage returns on investment
                                                        (23}
 are  in addition to this 4% charge.   Vilbrandt and Dryden
 indicate  that a 45% return is expected before taxes on a high
 risk  venture such as this.   An alternative would be the construc-
 tion  of only the ethanol plant by the chemical company,  which
 results in a return of 49%,  since the capital investment does
 not include the municipal built hydrolysis plant.   This return
would  require the municipality to absorb the necessary dumping
 fee charge.   It has been pointed out that a break-even point
with no dumping fee could be obtained by total plant operation
by the city.  Therefore,  construction of the total plant by the
community would be the most  logical decision.

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                             -92-




                      Table 6-3

                 ETHANOL PRODUCTION BY FERMENTATION

                          COST ANALYSIS
FERMENTATION PLANT  (5.4 million gal/year)
                              $1.7 million
RAW MATERIALS (excluding sugar)
    (NH4)2S04
   Steam
   Process Water
   Cooling Water
   Electricity
  225 Ibs.
750,000 Ibs.
 150,000 gals.
 630,000 gals.
  1600 KWHR
LABOR
   2 Laborers
   1 Supervisor
MAINTENANCE (Material & Labor)
SUPPLIES
FRINGE BENEFITS
PAYROLL OVERHEAD
LABORATORY
PLANT OVERHEAD

FIXED CHARGES

   Capital Return 4%, 2Qyears
   Taxes
   Insurance
 $ 2.85
  37.50
  15.00
  31.50
  16.00
$102.85
                    $144.00
                      84.00
                    $228.00
                    $235.00
                      26.00
                      34.00
                      34.00
                      34.00
                     114.00
                    $350.00
                      98.00
                      47.00
                                     $495.00

MANUFACTURING PRICE, NOT INCLUDING SUGAR


COST GAL., NOT INCLUDING SUGAR

SUGAR COST (Basis 500 ton Refuse, 50% Paper)

   15.3 Ibs.  sugar/gal.
   $0.028/lb, No Dumping
   $0.018/lb.  at $4.00 dumping

TOTAL MANUFACTURING PRICE

   NO DUMPING FEE
   WITH $4.00 DUMPING FEE
   CURRENT SELLING PRICE
                               $1302.8s/DAY


                               $0.087/GAL.
                               $0.43/gal.
                               $0.275/gal.
                               $0.518/gal,
                               $0.362/gal,
                               $0.52/gal.

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                            -93-
      The  capital  investment  for the total process would be  5.2



 million dollars.  Although this investment is very high,  it



 can  be justified  by  the  savings incurred by the  zero disposal



 cost.  If the municipality were presently paying $4.30/ton  for



 disposal,  a hypothetical profit of $720,000 would result.   This



 is approximately  a   141  return on the investment which is  well



 above any other expected returns for a city run operation.



 These calculations have been made on an assumption of a 50%



 paper composition;   if the actual plant paper were higher there



 would be  an additional profit due to the ethanol production.



 The  conclusion drawn from this preliminary cost analysis of



 ethanol production is that such a process must be considered



 as a possible user of hydrolysis sugars.



     Chapter 7 describes other chemicals which may be possible



 sources of demand for the hydrolysis plant product.  With these



 chemicals, as well as ethanol, a market study must be made to



 determine whether expanding markets exist for the product.  The



 necessity of such a study is illustrated by the magnitude of



 ethanol production capable of a 500 ton refuse plant, which



 could produce approximately 5.5 million gallons per year.   Al-



 though the existing ethanol demand could absorb the production



 from a small number of such plants,  it could not withstand the



 impact which would occur if every city of over 200,000 people



began producing ethanol.



     Although refuse hydrolysis is not a panacea for the refuse



disposal  problem,  it does possess the  potential to  alleviate



the problem in many municipalities.  Cities  which produce

-------
                             •94-
refuse high in paper content and in large quantities have



various alternatives open to them:   1)  own and operate a com-



bination hydrolysis-chemical plant, 2)  produce sugar by hy-



drolysis with sales to a local chemical producer,  and 3) entice



private industry into establishing a combination plant in the



community.  The final decision will be determined by the



ability of the municipality to raise the necessary original



capital investment and the competitive nature of the product.

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                             -95-
 7.  GLUCOSE AS A POTENTIAL RAW MATERIAL





     The production of ethanol by glucose fermentation has been



 outlined in Section 6.4.  As stated in that section, g]acose



 can be used in most processes which use molasses as a raw mate-



 rial.  Thus if the glucose solution from the hydrolysis process



 is sold at a lower price than molasses on a cost/lb sugar basis,



 then it may have potential as a raw material for production of



 chemicals other than ethanol.  Such processes which use molasses



 are described in the following sections.  The pertinent infor-



 mation which must be considered when evaluating such processes



 are:  competitive processes which do not require molasses



 (synthetic), the existing market, yield of product per Ib. of



 sugar, and the selling price of the product.



     It is not known a priori what the effect of producing a



 given product at a lower price will be on the market demand.



 It is possible that additional markets or uses will be estab-



 lished, thus increasing the demand for the product.  Such in-



 formation can only be obtained through a thorough market analysis,



 It is essential that such information be obtained since it would



 be foolish to attempt to produce a product for an already satu-



 rated market.



     The following information for the various chemicals  is



 taken from Reference (29) .   Most market and cost information



 are for the year 1963.



 7.1  Monosodium Glutamate



     Monosodium glutamate is a food flavoring produced by the



 fermentation of glucose with "micrococcus glutamicus".   It re-



quires a 15% glucose solution and produces approximately  0.27

-------
                          -96-
pounds of monosodium glutamate per Ib. of glucose.  The produc-



tion is on the increase with approximately 31 million pounds



being produced in 1963.  As of June 16, 1969 its selling price



was $0.47/lb.  Although synthetic processes are being developed,



fermentation was the only economical means as of 1963.



7.2  Citric Acid



     Citric acid is produced strictly by fermentation and is



primarily used in the beverage industry.  A 15 to 20 percent



sugar solution is fermented by "aspergillus niger".  Approxi-



mately 118 million pounds were produced in 1963 and sold at



$0.34/lb.  One pound of citric acid is produced for approxi-



mately two pounds of sugar.



7.3  Butanol



     Butanol was originally produced by fermentation of a 5%



sugar solution but has since been synthetically produced from



acetaldehyde.  The yield is 20% by weight of original sugar.



Three hundred million pounds were produced in 19.63.  The present



selling price is $0.13/lb.  It is used as a solvent and a raw



material for butyl acetate, resins, and plasticizers.



7.4  Lactic Acid



     Lactic acid is primarily used in the food industry and its



market is small — 5 million pounds/year in 1963.  It is pro-



duced by fermentation of a 15% glucose solution with an 85%



yield, or by the hydrolysis of lactonittrite.  The synthetic



process was just under development in 1963.  Its current selling



price if $0.17/lb for a 50% technical, grade solution.



7.5  Sorbital and Oxalic Acid



     Sorbital and oxalic acid can also be produced from a glucose



solution but they require a 50% and 60% solution.  Such high

-------
                             -97-
concentrations would require extensive evaporation of the hy-
drolysis plant sugars.  It is therefore unlikely that such
products could economically be produced from these sugars.
7.6  Conclusions
     Of the above chemicals, monosodium glutamate and citric
acid have the greatest potential for economic production with
refuse produced sugars.  Both can use low sugar concentrations,
approximately 15%, which could be economically produced by a
refuse hydrolysis plant.  In addition, the only available means
of producing these chemicals is by fermentation, thus eliminating
competition from synthetic processes.  The present market, as in
the case of all fermentation products, may not be large enough
to absorb the added production of many new plants,  but this
cannot be unequivocally stated without further market research.
All such possible uses for sugar must be considered,  since the
final solution will lie in establishing many such outlets for
the refuse sugars.

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                              -98-
8.  RECOMMENDATIONS FOR FUTURE WORK





     Although sufficient experimentation was conducted to estab-



lish the economic potential of the process,  there is still addi-



tional experimentation which must be done on a small scale before



a pilot plant can be built.  This work includes the study of the



effect of metal ions on the hydrolysis reaction, the ability to



react a slurry at low liquid to solid ratios, and the ferment-



ability of the sugars produced.  This experimentation would lead



to a more accurate pilot plant design, thus  increasing the proba-



bility of successfully producing a product at a marketable cost.



8.1  Metal Ion Effect on Hydrolysis



     When metal ions were present, low sugar hydrolysis yields



occurred.  Such ions were found to interfere with the 0-toluidine



sugar test resulting in false, low yields.  Although it is be-



lieved that such ions do not interfere with  the actual hydrol-



ysis, this hypothesis has not been proven.  An analysis procedure,



using ethylene diamine tetra acetic acid to  nullify the reac-



tivity of metal ions, is being developed. With such a procedure



a sample containing metal ions can be hydrolyzed and analyzed



for sugar content with and without addition  of the EDTA solution.



If the metal ions only affect the sugar test, the hydrolyzed



solution containing EDTA should show higher  yields than the



solution without EDTA.  Moreover, if the iron containing hydro-



lyzed solution treated with EDTA gives yields comparable with



hydrolyzed solutions from paper without iron, then this would



be positive evidence that metal ions do not  interfere with the



actual hydrolysis.

-------
                            -99-
      Since almost any alloy metals used in constructing  the



 hydrolysis reactor will corrode to some degree, it is essential



 to determine whether metal ions actually affect the hydrolysis



 reaction.  In addition, if metal ions do not affect the  hydrol-



 ysis, waste acids could be used as the acid catalysis.   Waste



 pickling aeids from the steal industry, which contain metal



 ions, may then be used in the hydrolysis process, thereby



 reducing the manufacturing cost of sugar.



 8.2   Flow Reactor



      It is essential that a model flow reactor system be built.



 The  enormous effect of the liquid to solid ratio on the manu-



 facturing cost has been shown.  A flow reactor system must be



 tested in order to determine what the minimum feasible liquid



 to solid ratio is for both the hydrolysis reaction and the



 equipment used.  A flow reactor is also needed to produce sugar



 in large quantities from actual refuse.  This would enable a reason-



 able  scale of sugar fermentation, and thus determine whether



 refuse contains any materials which would contaminate fermen-



 tation.



 8.3  General Plant Considerations



     The main manufacturing cost of the hydrolysis plant is the



 oil necessary to heat the slurry to the reaction temperature.



 If a system other than evaporation could be used to concentrate '



 the sugars, a more efficient heat recovery system could be



 designed.   Reverse osmosis can be used to concentrate sugar



 solutions,  and future experimentation may prove that it is more



 economic than evaporation.



     Presently there is  no internally proposed method for hy-



drolysis waste disposal.   It may prove economic to burn the



residual waste and use the generated heat as  an additional

-------
                             -100-
preheat source.  Before this can be proposed,  it is necessary



to determine the BTu potential of the waste.   In addition to



hydrolysis waste,  outlets for scrap metals should be determined



and possible uses  for CAS04 explored.



8.4  Sugar as a Raw Material



     Chapter 7 listed chemicals other than ethanol which can



be produced by sugar fermentation.  Although  the production of



ethanol seems to be economically feasible, a  cost and market



analysis should also be performed on these other chemicals,



It may be found that there would be a larger  economic advantage



in producing some  other chemical.  If such a  feasibility study



indicates an existing economic potential for  another chemical,



then an experimental program based on this chemical should be



established.

-------
                                  -101-
9.  SUMMARY AND CONCLUSIONS





     A survey of existing municipal refuse disposal processes



showed that high temperature incineration is one of the important



conventional disposal methods, and the projected disposal cost of



such a plant can be around $3/ton.  The main component of refuse



was found to be paper, 40 to 60%, and, as shown by Porteous, the



paper content of refuse is increasing.



     Porteous' process for refuse disposal, which utilizes the



refuse paper content as a raw material for sugar production by



acid hydrolysis, was studied.  Experimentation was conducted to



determine a kinetic model for paper hydrolysis which was then



compared with Saeman's model for wood cellulose hydrolysis.


                     Kl    K2
Saeman's predicted A	»• B	>• C irreversible reaction model



was found to accurately describe the reaction, but the determined



rate constants were found to differ from those predicted by Saeman.



Yields, approximately 75% of those predicted by Porteous with



Saeman's kinetics, were obtained.



     A hydrolysis plant design, using the experimentally



determined kinetics, was proposed.  Modifications of Porteous'



original design included, a hydropulper separation and pretreat-



ment system adopted for use from those used in the waste paper



pulping industry, a recycle stream for the continuous flow



reactor system, and a multi-effect evaporation system for



concentrating the sugar solution.




     A generalized computer program with variable refuse



tonnage, refuse composition, and operating conditions, was

-------
                          -102-
used to size the individual plant components and calculate



the total plant and manufacturing cost.  A 1% acid solution



and a 230°C reaction temperature, yielding 51% cellulose-



sugar conversion, were found to be the most economical hydrol-



ysis conditions.  The manufacturing cost of a 12% sugar



solution for various refuse compositions and plant capacities



was calculated and compared to the market price of molasses



sugars on a cost/lb. sugar basis.  This comparison showed



that under the proposed operating conditions cities with



populations greater than 200,000 with refuse containing 50%



paper, and 100,000 people with refuse containing 60% paper,



could produce sugar by acid hydrolysis at a cost comparable



to the existing market price of molasses and at a zero refuse



disposal cost to the city.  Moreover, a preliminary economic



study showed that ethanol could be economically produced by



fermentation of the sugars.  Other potential uses for the



sugar solutions include the production of monosodium glutamate



and citric acid.



     Porteous'  economic study indicated that a 250 ton refuse



hydrolysis and ethanol fermentation plant could make $4.00/ton



profit with refuse containing 60% paper, and $0.77/ton profit



with refuse containing 40% paper.  Although this study showed



that the hydrolysis process was not as economically attractive



as originally conceived, it still indicated that this method



of refuse disposal could eliminate the refuse disposal cost



for many U.S. cities.

-------
                          -103-
     Before the final step of establishing a pilot plant is



taken, it was recommended that a small scale flow reactor be



built.  Such a reactor would be able to confirm the pre-



dicted isothermal yields and produce sugars in large enough



quantities for fermentation experimentation.

-------
                              -104-
                          REFERENCES


 1.  Decisions of the Policy Planning Council, Refuse Disposal
     Report for New York City,  September 27,  1967

 2.  Bell, John M., "Characteristics of Municipal Refuse";
     Proceedings National Conference On Solid Waste Research,
     American Public Works Assoc.,  Special Report No. 29,
     February 1914

 3.  "Garbage:  Rosy New Future as  a Raw Material",  Chemical
     Engineering, April 22, 1968.

 4.  "Conversion of Organic Solid Wastes Into Yeast", Report
     prepared for the Solid Waste Program of  Public Health
     Service by Ionics, Inc., Mass., 1968

 5.  Porteous, A., "Towards a Profitable Means of Municipal
     Refuse Disposal", ASME Pub.  67-WA/PID-2

 6.  Meiler & Scholler, dissertations, Techn  'Hochshule,
     Munich, 1923

 7.  Saeman, J.,  "Kinetics of Wood Saccharification",  I & EC,
     January 1945

 8.  Browning, B. ,   The Chemistry  of Wood ,  Interscience
     Publishers, New York, 1963

 9.  Saeman, Buhl & Harris, "Quantitative Saccharification of
     Wood and Cellulose", I & EC, Vol. 17 #1, January 1945

10.  Wilde & Beightler, Foundations of Optimization,
     Prentice Hall, 1967

11.  Browning,  Methods of Wood Chemistry,  Interscience  Pub-
     lishers, New York, 1967

12.  Casey, J.,  Pulp and Paper, Vol.  1,  Interscience Pub-
     lishers, New York, 1966

13.  Levenspiel,  Chemical Reactor  Engineering,   Wiley & Sons,
     New York, 1962

14.  Daily & Bugliarello, "Basic Data for Dilute Fiber Suspen-
     sions in Uniform Flow with Shear",  Tappi, July 1961,
     Vol. 44 #7

15.  Daily & Bugliarello, "Rheological Models and Laminar Shear
     Flow of Fiber Suspensions", Tappi,  Dec.  1961,  Vol.  44,  #12

16.  Stepanoff,  Pumps and Blowers, Two-Phase Flow,  Wiley &  Sons,
     1965

-------
                               -105-
17.  ror.tana and Greene,  Corrosion Engineering,  Xc-Graw-Hill,
     New York, 1967

13.  G::ulich, G., "Improved Methods of Spent Sulfite Liquor
     Disposal", D.E. Thesis, Thayer School of Engineering,
     Hanover, N . K . ,  June 1969

19.  1-orry ,  Chemical Engineering Handbook, Fourth Edition,
     McGraw-Hill, New York, N.Y.,  1953

:C.  "Evaporation",  Chor-i^njl Enrrincsring, December S, 1963

21.  Kern,  Process Heat Transfer,  McGraw-Hill, 1950

22.  Guthrie,  "Capital Cost Estimating",  Chemical Engineering,
     March 24, IS69

23.  Vilbrandt and Dryden,  Chemical Engineering Plant Design,
     McGraw Hill, New York, N.Y.,  1959

24.  Peters and Timmerhaus,  Plant Design and Economics for
     Chemical Engineering,  McGraw Hill, New York, 1968

25.  Aris,  Chemical Engineering Cost Estimation , McGraw Hill,
     New York,  1955

26.  Saeman,  U.S.  Forest Research Labs, Madison, Wisconsin,
     Personal Communication, June 1969

27.  "Commodity Year 1968 Book", Commodity Research Bureau Inc.,
     140 Broadway,  New York, N.Y.

28.  Harris, "Fermentation of Douglas Fir Hydrolysis by S.
     Cerevisiae",  I & EC, September 1946

29.  Faith,  Keyes,  Clark,  Industrial Chemicals,  Wiley & Sons,
     New York,  1965

30.  Haselbaith,   Chemical Engineering ,  74(25):214,   1967

-------

-------
                           -107-



                         Apper.dix I


                QUANTITATIVE SACCHARIFICATION




     Quantitative saccharif ica-cion is an analytical technique


which hydrolyzes cellulose to glucose with a ininiir.um amount of


glucose decomposition.  Reference (9) from which the procedure


was taken, indicates that chemical yields of greater than S5%


can be achieved.



Procedure:


     A ground cellulosic sample of 0.35 grams is weighed and


mixed with 5 ml. of 72% sulfuric acid that has been cooled to


15°C.  This mixture is placed in a water bath at 30°C.  This


temperature is maintained for 45 minutes and during this time


the sample is stirred at 5 to 10 minute intervals.  After the


required time, the mixture is diluted in an Erlenmeyer flash


with 140 ml.  of water.  The diluted solution is autoclaved


for one hour at 15 psi.  This yield will be the maximum poten-

tial aldohexose yield of the sample  weight aldohexose x 100>
                                      weight sample

For a pure cellulose sample the potential glucose yield should


be

-------
                            -108-                               •


                           Appendix II

                           SUGAR TEST
       (EXPERIMENTAL WORK BY WILLIAM ELLSWORTH, SENIOR CHEMIST)


     Two methods of measuring the sugar content of the hydrolysis

product were compared:  spectre-photometry and ferricyanide oxi- ,

dation.  The latter test measures the total reducing power or

the solution including partially decomposed sugars.  The first  .

technique measures only the aldohexose sugars which are the

sugars of interest since they are fermentable.  All glucose

yields found in this report have been obtained by use of the

0-toluidine colorimetric test.

     It was found that metal ions cause a false reading to occur

with the colorimetric test, but that decomposed sugars have no

effect on the test results.  A summary of the test procedures

and the experimental study done on the 0-toluidine test follows.

A. Spectrophotometry:

Principle:  Aldohexoses react with 0-toluidine reagent to form

a green colored complex.  The solution is then put in a spectro-

photoineter.  The color follows Beers Law, i.e. color is propor-

tional to concentration of sugar up ro 1000 mg%,  where mg% equals

number of milligrams per hundred milliliters of solution.

Procedure:

  (1)  0.1 ml of sugar  solution is mixed with 6 ml of reagent.

  (2)  Mixture placed for 8 minutes in a boiling water bath,

      then cooled to room temperature.

  (3)  Read in spectrophotometer at 630 mu.

  (4)  % sugar found from calibration curve.  Calibration is

      done using standard glucose solutions.

Reagent:    60 ml 0-toluidine + 1.5 ml thiourea..  Dilute

           this to 1000 ml with glacial acetic acid.

-------
                             -109-
 Rcf erer.ccs :

      This method  is  a  modification  of  several  in the literature:

        (1) Nature, Vol.  183,  p.  108, 1959

        (2) Clin.  Chera. Acta,  Vol. 7, p.  140,  1962

        (3) Clin.  Chem. 8,  p.  215, 1962

 ^* Ox^^tj-on with Ferricyanide:
   I  & 'EcT:~AnaTytica 1  Edition/ Vol.  9  (1937) ,  p.  228

      In this test, sugar is  oxidized using  ferricyanide.   Excess

 ferricyanide is titrated with eerie sulfate.

 Procedure:

   (1) 5 ml of  sugar  solution (not containing more than 3.5 mg

      sugar) + 5  cc  of alkaline  ferricyanide.   Solution is

      placed in boiling water bath  for 5 minutes/  then cooled.

   (2) Add 5 ml of 5%  ^304  to above solution.   Titrate against

      0.01% eerie sulfate  using  setopaline-C indicator.

                     Comparison of Results

     Method A  estimates only  the glucose, whereas  Method B esti-

mates all kinds of sugars  —  pentose,  etc.

     Comparison of results:


       % Sugar (gms  sugar/100 grams paper)

                      Test A        Test B

        Method A       28.81         29.83

        Method B       31.55         31.87


C. Analysis of Spectrophotoinetric Test Reliability

1. Determination of Effect of Ferrous  Ion

     This test was run by taking a standard glucose  solution

and adding ferrous sulfate to it to give various concentrations

of iron.

-------
                           -110-
       Run
1) Standard Solution
2) Solution + 0.01% FeS04
3) Solution + 0.1% FeSO.
4) Solution +0.5% FeS04
5) Solution +1.0% FeS04
Experimental   Percent
  Result        Error
    120 mg %
     88
     46
     44
     39
26.6
61.6
63.4
67.5
     Ferrous sulfate was chosen because iron makes up about 50%
of Carpenter 20 CB3 and is the most reactive nmetal in it.  •
     The results show that even a very small amount of ferrous
ion causes a low reading.
2. Determination of Effect of Carpenter 20 CB3 on Tests.
     A 1.6g (1/2" of 1/4" tubing) piece of CB3-plus 20 ml of
0.5% H2S04 was put into the constant temperature bath at 268°C.
It was left for 30 minutes and then the 15 ml of it that hadn't
boiled out of the glass liner was diluted to 41 ml.
     A 102 mg% standard solution was used in this and the rest
of the experiments.
        Run                    Experimental  Expected  Error
1)  Standard Solution (SS)
2)  2 ml of SS + 2 ml H20
3)  2 ml of SS + 2 ml test
4)  5 ml of SS + 2 ml H20
5)  5 ml of SS + 2 ml test
6)  10 ml of SS + 2 ml H20
7)  10 ml of SS + 2 ml test
     A similar test gave almost the same results.
106 mg %
49
42
72
69
85
79
102 mg %
51
51
73
73
85
85
3.9%
3.9%
17.6%
1.4%
5.5%
0.0%
7.1%

-------
                             -111-


      This  experiment definitely  indicates  that,  at high tem-

 peratures  over  an extended  period  of  time,  the  0.5% H2S04  dis-

 solves  enough iron to affect the glucose test.   The fact that

 when the test solution was  added to the standard glucose solu-

 tion the glucose  concentration indicated was  always lower  than

 when just  water was  used, is consistent with  experiment #1.

 The  fact that the error goes down  with increasing dilution of

 the  test solution is also in agreement.

 3. Paper Hydrolysis  with No Metal  Contact  to  determine  the
   effect  of decomposed sugars in  the glucose test.

      The paper  hydrolysis was carried out  using  20  ml of 0.5%

 H2S04 + 0.2g of paper in a  glass lined reactor.   It was put

 into the bath at  265°C for  15 minutes, then diluted to  50  ml

 with H20.


     Run                     Experimental  Expected   Error

 1) Hydrolysis product  (HP)    51 mg %

 2) 5  ml of HP + 5 ml  SS       80           77 mg%    3.9%

 3} 5  ml of HP + 10 ml  SS      85           84        1.2%

 4) 5  ml of HP + 25 ml  SS      95           94        1.1%

 5) 5  ml of HP + 50 ml  SS      93           97        4.1%

 6) 5  ml of HP + 75 ml  SS     101           99        2.0%

 7) 2  ml of HP + 2 ml H90      24           25.5      0.6%
                       ^

 8) 2  ml of HP + 5 ml H20      13           14.6      1.1%

 9) 2 ml of HP + 2 ml SS       79           77        2.6%


     These results indicate some error,  but it is probably

within  experimental error.  See the next experiment.

-------
                            -U2-                             .   ':

4. Test to determine the overall accuracy of the dilution
   method of c necking the glucose test.

           Run,              Experimental   Expected     Error

1) 2 ml of SS + 2 ml H20        45 mg %      51 mg %     11.82

2) 5 ml of SS + 5 ml H20        50           51           2.0%

3) 5 ml of SS + 10 ml H20       34           34           0.0%

4) SS alone                    101          102           i.Ofc

5) SS alone                    106          102           3.9%


     See also runs 2, 4, and 6 of experiment #2.

     The average percent error of these eight runs is 3.0%.

There is some dilution error in these tests, and also some error

in the glucose determinations.

5. Conclusion

     The test is accurate to 3 - 4 percent, and is more consistent

if all the tests are performed simultaneously than if they are

done  separately.  Care must be taken that no ferrous ion is in

the solution.

     From other references it was learned that the amount of time

that the samples are heated is crucial, and that any metal ion

affects the tests.

     It has also been determined that allowing the sample to sit

in the test tube with the 0-toluidine solution for a short time

before heating it does not affect the test appreciably.

-------
                         Appendix III

                NONISOTHERMAL HYDROLYSIS RESULTS


                TEMPERATURE TIME HISTORY AND YIELD

                      0.2% Acid Runs
                      0.5 gram  Samples
                        20 ml Liquid

        Observations:   Base tenp.  = 100°C.   The body of
                        table reads temp, in °C.
IQuenched  5.4
     7.2
11
Run No . -

Time
/M- r\ \
j V •»-»• • /
i
: o
1
! 2
1 3
: A
\ 5
! 6
i 7
i 8
! 9
: 10
: 11
i 12
i 13
; 14



.Yield
V7/W %
paper
1 2



'

100 ' 100
120 119
138 139
153 '. 154
167 • 167
179 179
183 ' 189
i 200
' 202
1
,
;
j
|
i
i
i



1.4 ; 5.9
'
! 3
i
I
j

[
! 100
' 120
1 139
i 155
I 169
. 180
! 191
1 201
: 209
! 211
>
I
1
!
1
1

1



' 7.8
1
4





100
122
143
157
171
183
195
204
214
222









8.7

5 6
t
I

I

100 100
121 121
140 141
156 156
171 170
183 182
194 192
204 202
212 210
220 217
228 : 224
233 230
235
237


i i
,

12.8 ! 11.8
j
12.4!
                                                          Temp.
  Observation:

     6  =
     Temp, to  time curve for run was:

A + BT + CT2 + DT3 + ET4'
            A  =  99.9254
            3  =  23.0599
            C  =  -1.78918
            D  =  0.105227
            E  =  -3.11787 E-3
                            -113-

-------
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                                             -114-

-------
                            -115-
             TEMPERATURE TIME HISTORY  & YIELDS

                     1% Acid Runs
                     0.5 gram Samples
                     20 ml of Liquid
Run No,
Time , ;
(Min.)
0 100 100
1 118 119
2 127 137
3 152 152
4 165 165
5 175 177

6 183
7
o
9
10
11 :
13

Yield
w/w paper | 9'97 u-85
Time j
Quenched 4'8 5'6


100
119
127
153
165
177

186
191







19.70

6.6


100
119
137
152
165
177

187
197
202


i

!

; 30.60

7.6


100
119
137
152
165
177

188
197
203
205





! 31.30

8.2
i
i
100
119
137
152
165
177

187
197
203
210





31.56

8.6

i
100 i
119
137
152
165
177

188
197
203
210
219
220

(

19.08

10.4


100 i
119 i
137 ]
152 !
165 j
177 j
(
187 !
197 !
204 1
211
219
224 j
227 i
i
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|
11.6 |
!
                                                                      CJ
                                                                      -P
                                                                      (U
                                                                      A
                                                                      £
                                                                      o
                                                                      EH
   Observation:   Temp, to time curve for run was:

                   0 = A + BT + CT2 + DT3 + ET4
                     A = 99.6517
                     B = 21.3828
                     C = -1.52206
                     D = 7.43993E-2
                     E = -0.001729

-------
                        Appendix IV

                      COMPUTER PROGRAMS
A.  HOOKE-JEEVES SEARCH AND RUNGE-KUTTA NUMERICAL
    INTEGRATION
     Used for calculating parameters of Arrhenius' equations

which best fit the data of the non-isothermal analysis.

     The Hooke-Jeeves search was originally written for  two

dimensions by Steve Smith, Tuck-Thayer, 1967.  It was modi-

fied for four dimensions and incorporated with a 4th order

Runge-Kutta integration routine written by Professor Converse,

Thayer School of Engineering.  A program flow sheet and

internal program documentation are given to help explain its

operation.
                           -116-

-------
                       -117-


                      HOOKE JEEVES SEARCH
                                   INPUT

                                Yields & Times
To Runge Kutta ';
 Subroutine
                                  INITIALIZATION


                    Set X' 's  i=l to 4  (Arrhenius Parameters)

                    Set D-L'S  i=l to 4  (Step Sizes)           ••

                    Set  L = Search Convergence Criterion     '
                                Let Bi = Xi
r"         "
! Calculate Sum Sq Error With
i X,- = B, + D.
                           = B  - D±
                       i Save Suboptiumum X.!s
    MINIMUM OF

     FUNCTION

-------
                      -118-

From Hooke-Jeeves Search
                                                          It'*
                RUNGE KUTTA SUBROUTINE
                           T~

        INITIALIZATION
        Set X(l)  = Cellulose content
            X(2)  = Sugar content
              t   = Time of initial conditions
              tn  = Time of final conditions
                    Fourth Order
                    RUNGE KUTTA
                 EQUATIONS
                 Temp T = f(t)
                        = g1 (XX, X2,T)
                        = g"(X3,X4,T)


                   X(2) = h"(K1,K2,t)
                            iYES
                 Calculate:
                 Sum of Squares
                ! Error of fit
    To Hooke-Jeeves Search  :

-------
                                                                      /?
                                 -11,9-,
1 ?."" This program  calculates the 4 parameters of 2 Arrhenius
2 RFM equations which  best fit the curve  sf  a non-isothermal
? RE.M kinetic analvsis.
50 PRINT' "INPUT NUMBER OF TIME POINTS*'
52 i "1 T9=7
60 PRINT "INPUT TIME (WIN), YIELD (FRACT)
«-2 FOR N = 1 TO T9
6* RF/'D T(N),Y(N)
65 Nr.XT N
C6 DAI A 5.6, .11,6.6, .1995,7.6,. 306, 8. 2, .313, 8. 6,. 3156
66 DATA 10.2, . 190F.11.6, .03
100  REM  THIS PROGRAM DOES A KOOKE-JSEVES PATTERN SEARCH AS
110   '   DESCRIBED  IN SECTION 7-08 OF  WILDE  AND BEIGHTLER ,
120   '   "FOUNDATIONS OF OPTIMIZATION,"  PP.  307-310.  PRESENTLY  THE
13G   '   PROGRAM  IS LIMITED TO FOUR INDEPENDENT VARIELES, XI. X2 ,X3 , X4
150  '   STATEMENT  250      LET Xl=  INITIAL  VALUE OF 1ST PRE-EXPOTENTIAL
160  '   STATEMENT  260      LET X2=  INITIAL  VALUE OF 1ST ACT ENERGY
170  '   STATEMENT  270      LET X3=INITIAL VALUE OF 2ND PRE-EXPOTENTIAL
160  '   STATEMENT  280      LET X4 =  INITIAL  VALUE OF ' 2ND ACT ENERGY
190  '   STATEMENT  290      LET Dl = INITIAL VALUE OF XI STEP SIZE
200  '   STATEMENT  300      LET D2 = SAME X2
210  '   STATEMENT  310      LET D3 = SAME X3
120  '   STATEMENT  320      L?;T D4 = SAME X4
230  '   SUE ROUTINE 1490  RUNGE-KUTTA  INTEGRATION
240    '   *-*-*r##*******#*###£i^j) OF DESCRIPTION***""'***'***'**********
250 LET Xl= 600000 'ACTUALLY 6E19 SEE  LINE 2334
260 LET X2=45000
270 LET X3=24000 'ACTUALLY 2.4E14 SEE LIME 2335
280 LET X4=32800
290 LET D1=1E5' GIVE LARGE SEARCH MARGIN
300 LET D2=1000' KEEP IN FEASIBLE RANGE
310 LET D3=1E4' GIVE LARGE SEARCH MARGIN
320 LET D4=1000' KEEP IN FEASIBLE RANGE
330 LET Pl=0
340 LET P2=0
350 L?T P3=0
360 LET P4=0
370 DIM P(300,4)
SCO LET P(0,1)=X1
390 LET P( 0,2)^X2
400 LET P(0, 3)=X3
410 LFT P(0,4)=X4
420  GO SUE  1490
430  LET FO=F
450 FOR 1=  1 TO  290
460  GO SUB 1490
^70  IF F>FO THEN 500
480  LET FO=F

-------
                                 -120-
SE£R     (continued)

490  GO TO 540
SCO LET P1=X1
510 LEI P2=X2
520 LET P3=X3
530 LET P4=X4
5-0  LET XO  = XI
550  1,?1 n*Xl+Dl
560  GO SUE  1490
570  IF F>FO THEN  600
5 SO  LET FO  = F
590  GO TO 670
600  LET Xl=XO
610  LET X1=X1-D1
620  GO SUB  1490
630  IF F> FO THEN 660
b40  LET F0= F
650  GO TO 670
660  LEI XI  = XO
670  LET XO=X2
6SO  LET X2= X2+D2
690  GO SUB  1490
700  IF F> FO THEN 730
710  LET FO  = F
720 GO TO  800
730  LET X2= XO
740  LET X2= X2-D2
750  GO SUE  1490
760 IF F>FO  THEN 790
770 LET FO=F
760 GO TO  800
790 LET X2=  XO
£00 LET X0=  X3
£10 LET X3=  X3+D3
&20 GO SUB  1490
£30 IF F>FO  THEN 860
640 LEI F=FO
650 GO TO  930
£60 LET X3=XO
£70 LET X3=  X3-D3
f£0 GC SUB  1490
690 IF F>FO  THEN 920
900 IET F0=  F
910 GO TO  930
920 LET X3=  XO
930 LEI X0=  X4
940 LET X4=  X4+D4
950 GO SUE  1490
960 IF F>  FO THEN 990
970 LET  FO=F
960 GO TO  1190

-------
                                 -121-
SFr R     (continued)

990 LET X4 = XO
1CCO LET X4 = X4-D4
1010 CO SUB 1^90
1020 IF F>FC THEN  1050
1030 LET FO=F
1C'-0 GO TO 1190
1050 LET X4=XO
1C6C    '   ***********#EKD OF ABOVE DESCRIBED  ROUTINE***************
1070    '   THE FOLLOWING TWO TESTS DETERMINE IF THE NEW BASE POINT  OR
10F-0    '   ANY OF  ITS SURROUNDING PERTURBATIONS ARE BETTER THAN THE LAST
1090    '   BASE POINT.   IF NOT THEN A NEW  BASE POINT MUST BE CALCU-
1100    '   LATSD USING  A SMALLER STEP SIZE.
1110 IF P1<>X1 THEN 1190
1120 IF P2<>X2 THEN 1190
1130 IF P3<> X3 THEN 1190
1140 IF P4<> X4 THEN 1190
1150 LET Xl= F(l-l.l)
1160 LET X2 = P(I-1,2)
1170 LEI X3= P(1-1,3)
1180 LET X4 = P(I-1,4)
1190 LET P(I,1)=X1
1200 LET P(I,2)=X2
1210 LET P(I,3)=X3
1220 LET P(I,4)=X4
1 2?0    '   THE FOLLOWING FOUR STATEMENTS CALCULATE AND ASSIGN
1240    '   VALUES  TO THE NEW BASE POINT.
1 250 FOR J=  1 TO 4
1260 LET P(I+1,J)=2*P(I,J)-P(I-1,J)
1270 NEXT J
1280 LET Xl= P(I+1,1)
1290 LET X2 = P( 1+1,2)
1300 LET X3=P(1+1,3)
1310 LET X4 = P( 1+1,4 )
1320 LET Z9=D1+D2+D3+D4
1321 IF Z9<100 THEN 1430
1330    '   THE NEXT FOUR STATMENTS REDUCE  TEE  STEP SIZE IF THE PROCEEDING
1340    '   SEARCH  DID NOT FIND A NEW MINIMUM.
1350 FOR J=  1 TO 4
1360 IF P(I+1,J )<:>P(I,J ) THEN 1420
1370 TEXT J
1380  LET Dl=Dl/2
1390  LET D2=D2/2
1400 LET D4= D4/2
1410 LET D3= D3/2
1420  NEXT I
1430  PRINT  "MINIMUM OF FUNCTION IS"FO
14-^0 PRINT "COORDINATES ARE"xi;x2^x3;X4
1450 PRINT' " FINAL STEP SIZES ARE D1;D2;D3;D4
1452 FOR J=  1 TO T9
1453 PRINT SQR(E(J)),Y(J)

-------
                                                                     /.
                                  -122-
£E£R     (continued)

145-i NEXT J
1460 PRINT
1^70 PRINT"IT";I
14i?C GOTO 2500
1490 ' THIS IS START  OF  RUNGE-K.UTTA
1491 IF XI<0 THEN 1530'  PUT RESTRAINT ON SEARCH  VARIABLES
1193 IF X2<0 THEN 1530
14°4 I? X3  Tl THEN 2360  ' END OF  INTEGRATION
2311 FOR J=l TO T9' PICK OUT ERROR OF EACH POINT
2212  IF A:-S(T-T(J))>.OI THEN 2317
2313 LKT E(J) = (X(2)-Y(J))~2
2314  IF E(J)>500 THEN 2341
2317  NEXT  J
2320 C-CTO  1970

-------
                                  -123-
fr,/>R      (continued)

7330' C WILL BE  ABSOLUTE TEMP -TIME  FUNCTION
2331 LET  C=273+99 .6517 + 21.3828*T-1.52206*T's2+7.4399E-2*r~3
2332 LET  C=C-1 ,729E-3*T~4
2333' ^ RRHE NIUS  FUNCTIONS FOLLOW
2331 LET  Kl= XI *!El4*EXP(-X2/(1 .98*C ) )
2336 LET  K2= X3*lElO*EXP(-X4/(1.98*C))
2337' CONSTRAINS  ON K1.K2
2338 IF Kl>20 THEN 2341
23^0 IF K2<20 TEEN 2345
2341 LET  F=F+10
23^2 GOTO 2400
23-M ' DIFFERENTIAL EQUATIONS FOLLOW
2345 LET  G (1 )=-Kl*X (1)
23^6 LET  G(2)=-K2*X(2)+K1*X(1)
2350 RETURN
2355' CALCULATE  SUM SQUARE ERROR
2360 LET  F=0
2370 FOR  J= 1 TO T9
2380 LET  F=F+E(J)
2381 ''EXT J
2382 LFT  J5=J5+1
2383 IF J5=100 THEN 2395
2384 IF J5=160 THEN 2395
2385 IF J5=200 THFN 2395
2386 IF J5=250 THEN 2395
2387 IF J5=350 THEN 2395
2388 IF TIM>320  TEEN 2395
2389 GOTO 2400
2395 PRINT F.XI,X2,X3,X4
2396 FOR  J=l TO  T9
2397 PRINT' SCR (E (J ) ) , Y (J )
2398 NEXT J
2399 PRINT "l",I
2400 IF J=100 THEN  2402
2401 GOTO 2405
2402 PRINT J
2405 RETURN
2500 El£>

-------
                            -124-
B.  HYDROLYSIS PLANT SIMULATION PROGRAM
            by R. Fagan

     The hydrolysis plant simulation program can be used to
calculate the manufacturing cost of sugar for any city with
local refuse composition and local operational cost.  Internal
documentation is given to aid the reader in following the pro-
gram.  The inputs to the system are either external or internal,
External inputs are requested by the program at run time, and
internal inputs must be changed before run time.
Line Number
                           External Inputs
 230 -  270      Refuse tonnage and composition
 270 -  500      Plant operational variables
                    A. yield
                    B. reactor residence time
                    C. acid concentration & temperature
                    D. solid to liquid ratio
                    E. recycle ratio
3790             Dumping credit
3810             Waste disposal charge
3830             Interest rate and years of operation
1820-3010
3332
3370-1442

3570-3780
 850-1590
3070-3250
3450-3544
3900-4165
         Internal Inputs
Equipment cost parameters
Equipment cost update %
Factors for calculating total fixed capital
cost from installed equipment cost
Manufacturing raw material cost and indirect
manufacturing cost factors
         Outputs
Material balance
Equipment size and cost
Fixed capital investment
Manufacturing cost analysis

-------
                            -125-
     By inserting these variables, an economic feasibility



study can easily be performed on any city which might wish



to use acid hydrolysis to dispose of its refuse.

-------
                                 -126-
COST3

100 DIM S(30),P(30),I(30)
110 DTK K(30)
120 DIMT(30)
130 LET A$(I)="CELLU^OSE"
140 LET A$(2 ) = "WATER '
150 LET A$(3)="ACID"
160 LET A$(4)=  'SUGAR
170 LET A$(5)='*D  SUGAR*'
180 LET A$(6)=*S  INERTS"
190 LET A$(7)="L  INERTS"
200 LET A$(8)=' LIME
210 LET A$(9)="SEPARABLES"
220 REM *******MATERIAL  BALANCE**************
230 PR INT" INPUT TOTAL  TONS WASTE*'
240 INPUT S' TOTAL  TONS/DAY WASTE
250 let  jl=s
260 PRINT "INPUT  FRACTION  PAPER.GARBAGE,SEPARABLES  IN  WASTE
265 INPUT1 F1,F4,F3
270 PRINT"INPUT FRATION  CELLULOSE IN PAPER
272 INPUT F2                               '         ;
273 LET  F5=1-F2
280 PR I NT" INPUT' TIME  TO  MAX YIELD IN MIN"
290 INPUT' T5
3co FRINT"INPUT CELLULOSE FRACTION CONVERTED AND  SUGAR PRODUCED'
310 INPUT Y1,Y2
311 LET  Y3=1-Y1
320 PRINT"INPUT FRACT ACID,SOLID TO LIQUID,REACTION TEMP CENT
330 INPUT C2,C1,T
340 LET  C2=C2*100/93'CORRECT FOR 93$ ACID
360 LET  P=  F1*S
370 LET  C=  F2*P'  CELL
360 LEI  M=F3*S'  SEP
390 LET  G=  F4*-S'  GAR
400 LEI1  K=  F5*P'  CLAYS
410 LET  Sl= S-M'  SOLIDS  TO REACTOR
420 LET  1=  ,5*( G+K)' TOTAL INERTS TO  SYSTEM
430 LET  L=  S1/C1' TONS/DAY
440 LET  X=  L-S1'  WATER ADDED AFTER HYDRO
450 LET  Tl= ((L+S1)*T-2*S1*20)/X' REQUIRED TEMP
460 LET  Al= C2*L' TONS/DAY ACID
470 REM****************RECYCLE PROBLEM*********************
480 PRINT"INITIAL FRACTION INERTS" ;i^c
490 PR INT"INPUT  II,INERT RATIO FINAL*
 500  INPUT  II
510 LET  R4= I1/Y3'  RATIO INERTS TO CELL OUT
 520 LET  B=  I/R4'  TOTAL CELL BLEED
530 LET  R=  (B-Y3*C)/(Y3-1)' RECYCLED CELL
 540  LET  Rl= C+R'  TOTAL CELL  IN REACTOR
 542  REM
 543  REM

-------
                                   -127*
55C Li: RZ = Y3---R1'  TOTAL CELL LEFT
5f,0 LEI f<3= l.r-tY2*Rl' TOTAL WEIGHT SUGAR FORMED
570 LET S3= I+C-s-R+Il*(C+R)' TOTAL  SOLIDS IN REACTOR
530 LIT v;= S3/C1' TOTAL WATER RSQ
soo LET ;-.3 = c2•--;•:' TOTAL ACID REQ
£00 LET '/1=',;-L-R-R4---R 'ADDITIONAL WATER TO RECYCLE
61 G LEI F=VS*-;•:+. l^(D-rGl)
620 LET A<1=A3-A1-A3/ (W-F )*(R+R4*R ) 'ADDED ACID
630 REM Gl= GLUCOSE  OUT' WITH WATER
640 LET GI= R3-R3/(W-F)*(R2-*-Il*Rl)
650 LET D= (I-Y3-Y2)*Rr*l.l' TOTAL  DECOMPOSED SUGAR  IN  WASTE
rfoO LET Dl= D-D/( VJ-F ) * (R2+I1*R1)
670 LET D2= !-!/(W-?)*(R2+I1*R1)
CSO LET V?.'.=W-.1*(D+G1)
690 LEI W5-W4-V9*V-7
7CO LET T2 = ( (V/l-f2---(R"R4+R))«-T-2^(K*-R4+R)*177)/V7l
705 LET 12 = (Ti-X+T2-V7l)/W'TEMP OF   IX WATER CENT
710 LET A5=A3-A4-Al' ACID OUT WITH  SOLIDS
720 LET £7= Y2-C-1.1' SUGAR PRODUCED IF NO RECYCLE
730 LET T.>;9=W5-R2-R1*II
7<0 LEI" N6= W9-:-(A3-A5)/98-*-13' WATER OUT OF NEUT
750 LET N7=N6-(P.3-A5)/9G*13S
760 LS'I L9=(A3-A5)/e8* 100 'LIME NEEDED
770 LET G2=(:.3-A5)/98*136*(G1/(N6+L9))
7£0 LET G3= G1-G2 '  SUGAR TONS/DAY OUT OF  PLANT
790 LET S9=3-Kl-'--'B-rM/2'TONS PER DAY  OF SOLID WASTE
600 PRI_\T"DO YOU WANT MATERIAL FLOW BALANCE YES OR NO"
sic INPUT y.$
820 IF MS="NO"  THEN 1580
830 PRI:;T"SEPARATION SYSTEM"
640 PRINT
650 PRINT"SEPARATOR","IN","OUT T/D","IN","OUT T/HR"
660 PRINT "WASTE",S,S-M,S/24,(S-M)/24
S70 Fr,I\\T A$(2),S/.02, ( £-K )/. 5. ( S )/. 02/24 ,( S-M )/. 5/24
e:c PRINT
c 90 PRINT "•"•^-•*«^i:-*****•»•*******«-************#*#**«•*#•«•*#****#"
900 PAINT
910 PRINT"REACTOR","IN","our T/D","IN","our T/HR"
920 PRINT ;.$(!),Rl,Y3*RlpRl/24,Y3*Rl/24
930 PRIKT Ac(2)„W,W4,W/24,W4/24
940 PRINT At(3)sA3,A3,A3/24,A3/24
950 PRINT Ac(4),Z9,R3,Z9,R3/24
9cO PRI>?i A$(5},Z9,D,Z9,D/24
970 PRINT .\S(6),IlttRl,Il*Rl,Il*Rl/24.Il*Rl/24
960 PRib:T A$( 7) ,1,1,1/24,1/24
990 PRINT
IO-;C ?RI I\7I
"; 050 PRi\T"';i'**********************************************
1060 PRINT
1070 PRINT"FLASK","IN T/D","OUT T/D","IN T/HR","our  T/HR"

-------OCR error (C:\Conversion\JobRoot\Region 5\00000BC1\tiff\2000ZA4Q.tif): Unspecified error

-------
                                  -129-
COST 3     (continued)

1590 LET El=  G3/74
j. c 00 R^,''i '*"•""*'*'*• w..-•*>--A-w.\--X---»
1G10 LET Fl=  U*200G/24/62.4'FT~3/!-IR OF FLOW TO  FLASH
1020 LSI E2=  F1/.134' GAL/HR TO FLASH
1C30 LET S5=  S4/.134' GAL/HR THROUGH REACTOR
IvVO LET C5=  (33-l)/24' IONS SOLID/RR TO 1ST CENT
1650 LET C&=  V.'5/24*iOOO*2/70'FT'"'3/liR TO CENT OF  WATER
1&60 LET Kl=W9*2COO/24/&2.4'FT'VKR TO CENT1
1C70 LET N2 =  N1/.134' GAL/HR TO CENT 2
ItSO LET N3=  (A3-A5)/9S*100/24' TCNS/KR OF LIME  TO CENT
1690 LET N8 =  N7*2000/63/24' FT"3 /HR TO EVAP
1700 LET N9=NS/.134'GAL/MIN
1710 LET S3 =  SI
1720 LET Pl=  S3/. 02*1000*2/24/62.4' FT~3 TO PUMP 1 TO PULPER
1730 LET S2=  El/(N7*2000/24)'  FRACTION SUGAR IN  LIQUID
174-0 LET ?2=  Wl*2000/62.4/24'FT~3/KR TO 1ST MIX
1750 LET P3=  L*2000/62.4/24' FT~3/KR TO FRESH REFUSE
1"60 LET P4=(A1+A4)*2000/24/(62.4*1.8)'FT~3/HR  OF ACID
1770 LET P5=  (s3/.C2-S3/.5)*1000*2/24/62.4'FT"3/HR PULP RECYCLE
17£0 LET P6=  P1-P5' FRESH WATER TO PULPER
1730 LET Hl=  P2+P3' THROUGH HEATER AND COND
1SOCPRINT
1S10 PRINT
1620 R'"".V-U-WW-X--X--X-V.-'---^-EQUIPMENT COST*****************
1330 1<2M STORAGE HOPPER 3 DAY  CAPACITY
1S40 REM ASSUME REFUSE IS  500  LB/YD~'3
1£50 LET G(l}= 3*S*2000/500*9'FT~3
1660 LET ?(1)=S(1}".9
1370 LET  I(1)=1.1*P(1)
IcoO REM CONVEYOR 18 INCH PULLEY MAGNETIC TYPE
1S90 LSI  S(2)=100'FT
1900 LEI P(2)= S(2)".65*450*3/250+1000
1910 LEI  1(2)= P(2)*1.62
1920 LET H(2)=l
1920 Ii5M  SEPARATION KYDROPULPER SYSTEM
1940 RIM
1950 LET S(3}= Sl'TONS/DAY
I960 LET ?(3;=(S(3)/80)".6*8E4
1970 LET  1(3)= P(3)*1.6
I960 LET E(3)=:20*S/24
1990 I
-------
                                   -130-
 COSTS    (continued)

 2090 LET S(5)=(A1+A4)*10*2000/(1.83*62.4)*74.8'GAL
 2100 LET P(5)=(S5/1E5)~.63*15000.
 2110 LE-:  I(5)=P(5)*1.85
 2120 REM 5LASK CHAMBER 2 KIN  RESIDENCE TIME
 :.130 LET S(6)= F1/60*2'FT~2
 21-'0 LET P(6)= (S(6)/62.8r.65* 2500
 2150 LET C(6) = ?(6)* 1.05*3-P(6)
 2: SO LET 1(6)= P(6)* 2+C(6)
 2170 LET P(S)= C(6)+P(6)
 2i?0 REM CENTRIFUGE  ONE
 2190 LET S(7)= C6/(.134*60)'  GAL MIN OF WATER 'TO  CENT
 2195 I? S(7)>350 THEN 2220
 2200 LET P(7)= (S(7)/350 )~.6*9E4
 2210 LET 1(7)= P(7)» 1.6
 2211 LET X7=l
 2212 LET h(7)=S(7)
 2213 GOTO 2230
 2220 REX
 2222 LET P(7)=9E4 + ((S(7)-350 )/350)~.6*9E4
 2223 LET I(7)=?(7)*1.6
 2224 LET X7=2
 2225 LET H(7)=S(7)
 ^230 RSM CONTINUOS FLOW NEUTRALIZER
 2250 REM IN LINE KIXER
 2260 REM DESIGN 150 PSI
 2270 LET S(8)=N1/.134/60'GAL/MIN
 2260 LET  P(8) = (s(8)/500r.6*5000
 23CO LET  I(S)=P(8)*1.6
 2305 LET  H(6)=S(8)/5CO*5
 2310 REM LIME STORAGE
 ^1° r^  ;>(9) = (A3-A5)*lGO/9e*2000*10/85'FT~3 FOR  10 DAYS
 •^JJ Li^'i  ?^9;=S(9) .9
 2340 LET  I(9)=l.l*p(9)
 235C  REM  CEl^RIFUGE 2
 3c,0 LET  S(10)= N2/60' GAL MIN
 •57H  ~ .rrrn  rj / I I-. \ - I r- I 1 r\ \ / -, ~i r \ ~ m.
7"57n , .
j. ~ t ^ lj^
23SO LET 1(10)=  P(10)» 1.6
2390 LET li(10) = (S(10)/375)*100'K.P.
2400 REM ;,UX DIRECT FIRED HEATER
2-110 GO SUB  4170
2<11 LET X5=(K4-212)*5/9+100
2420 REM T25.T1
2<22 ?RIXT"TEKP  TO  HEATER DEG F AND  c  ,K4,i<5
24?3 px""vT
2-',25 FRIXT"EVAPORATCRS"
2425 ?RINT"STZAM FROM FLASH,USED";w£i,i)/2000; TONS/ER
2427 PRiXT"EFFECT","VAPOR","TONS/KR
242c i-'OR J=2 TO  7
2.429 PRINT J-l, W(J , 1 )/2000
2430 NEXT J

-------
COST 3     (cor.t inued)
     LFT S (II } = (X+W 1) * (T2-K 5 )* 9/5* 2000/24 'BTU/HR
1440 LET P(ll)=  (S(11)/5E6)~.85*20000
2450 LEI I(11)= P(ll)*1.63
2450 REM OIL rXD  OIL STORAGE BASED ON   1.5E5 BTU/GAL
247C LET C=(S(11)/1.5E5/.85)'GAL/HR AT  85 % EFF
2-4?C> LET 01= 0*24' G.-L/DAY
2490 LSI S(12)= 01*10' GAL FOR 10 DAYS
2500 IF S(12)>4E4 THEN 2540
2510 LET P(12)=  (S(12 )/lE4)~.30*1600
2520LST I(12)= P(12)*  1.4
2530 GOTO 2560
25^0 LET P(12)=  (S(12)/3E5)~.63*3E4
255G LET 1(12)= P(12)* 1.85
2560 RSF *##w-,i-*pTjMPS****#***
2570 REX ** FRESH WATER TO PULPER
2580 REM OUT PSI= 60
2590 LET S(13)= P6'  FT~3/KR TO PULPER
2600 LET K(13)= 60*  S(13)*7.27E-5
2610 LET P(13)=  (3(13)7.134/60*60/1000)".52*600
          H(13)=  E(13)/.8                            :
         I(13)= P(13)*2.41
2640 REK    PULPER RECYCLE PUMP
2650 LET S(14 )= P5
2fa60 LET p(14)=  (S(14 )/.134/60*60/1000)".52*600
2670 LET K(14)= 60*S(14)*7.27E-5
26SO LET I(14)= P(14)*2.41
2690 LET E(14)= H(14)/.8
2700 REX XOYNO SCREW FUMP FROM PULPER   TO REACTOR
2710 LET S(15)=  (S1+2*S1)*2000/24/62.4'FT~3/HR
2720 LET E(15)= 400*S(15)*7.27E-5
27?C LET P(15)=  (S(15)/.134/60*400/1000)".52*600
2740 LET H(15)= K(15)/.8
2750 LET I(15)= P(15)*2.41
27r.O REM I12S04 FEED  PUMP
2770 REM CONTROLLED  VOLUME PUMP
?7fO LET S(16)= P4
27SO LET 1-1(16)= 500* S (16 )*7 . 27E-5
2800 LET P(16)=(S(16)/.134/60*500/1000)*.7*1200
2810 LET K(16)= H(16)/.8
2S20 LET I (16)= P(16)*2.41
2830 REI'i. REAC10R  KOYNO RECYCLE PUMP
2640 LFT S(17)=  (Wl+R+R4*R )/62. 4*2000/2-4
2650 LET K(17)= S(17 )*500*7.27E-5
26SO LET P(17)=  (S(17)/.134/60*200/1000)".52*600
2870 LET I (17)= P(17)*2.41
2F.60 REM FEED WATER  TO HEATER PUMP
2t90 LET S(18)=(P+W(1,1))/62.4'FT"3/ER
2900 LET H(18)=S(18)*400*7.27E-5/.8
2910 LET P(18)=(S(18)/.134/60*400/1000)".52*600
2920 LET I(18)= P(18)*2.41

-------
                                  -132-
COSTS     (continued)

:930 REX  MOYNO  SCREW FOR LIMEE
2940 LEI  S(19)= 2*N3/85*2000
2950 LET  h(19)= S(19)*ICO/.8*7.27E-5
7950 LSI  ?(19)=(S(19)/.134/60*100/1000)".52*600
2970 LEI  1(19)= P(19)*2.41
2980 RE>':  6  STAGE EVAPORATION SYSTEM
29S2 LET  P(20)=S(20)".53*1200*6
2983 LfT  I(20)=P(20)*1.9
2990 REM  CONDENSER
2';93 LET  P(21)=(S(21)/1000)". 65*9000
2995 LET  I(21)=P(21)*2.34
3000 LET  P(22)=(S(22)/62.8)".65*2500
3030 LET  I(22)=P(22)*2
3015 PRINT
3016 PRINT
3017 PRINT"DO YOU WANT EQUIPMENT SIZE AND COST YES  OR  NO
30IS INPUT  Y$
3019 IF Y$="NO" THEN 3290
3070 pRi>s;'i>"*****-****CCST ANALYSIS*******************,,
3cso PRTMT"EOUIPMENT"/'SIZS","  ","P COST","IN COST-"
3090 PRINT"HOPPER",s(i),"FT"3",p(i),i(i)
3100 PRINT"CONVEYOR",S(2),"FT",P(2 ),I(2 )
sue PRINT"HYDROPULP',s,'TONS/DAY' ,p(3),i(3)
3120 PRINT"REACTOR" ,s(4),  FT"3",p(4),i(4)
2130 PRINT"ACID STORAGE',s(5),"GAL",p(5),i(5)
3140 ?RINT"FLASE cKAMIf,s(6),  FT"3",p(6),i(6)
3150 PRINT"CENT";X7,S(7),"GAL/MIN" , P ( 7 ), I ( 7 )
3160 PRINT"NSUT",S(S),"GAL/MIN"tp(8).i(8)
31VU PRIXT"LIKE ST",S(9),"FT"3",?(9),I(9)
3160 PRINT"CENT i",s(10),"GAL/MIN",p(10 ).i(10 )
3190 PRi:rr"HEATER' ,s( 11), "BTU/HR",P(II). 1(11)
3200 PRINT"OIL  ST",S(12),"GAL",P(12).I(12)
3210 PRINT"EVAP",s(20),' FT~2",P(20),i(20)
3220 PRINT"CCND",s(21),"FT"2",P(21).i(21)
3230 ?3!NT"COND PO1" , S( 22 }, "FT'^3" , P( 22 ), I( 22 )
32^-0 PRI",T
3250 PRINT"PUXP","FT"3/hR","K.P.","P.C.","l.C."
3260 FOR  1= 13  TO 19
3270 PRINT"   ",S(l).H(l).P(l)fl(l)
3230 NEXT I
          p=o
33CC LET 1-0
3310 FOR 1= l TO 22
3320 LEI P= P+P(I )
3330 LEri T= T+I(I)
2350 PRINT
3352 LE'i ?=?*••!. 06'6% ESCALATION  FOR KID 1969
3353 LET T= T*1.06'65S ESCALATION
3360  PRINT

-------
-133-
          " ;B; ^DOLLARS"
          ]'_ jF-^" DOLLARS'^
          " ;C ; "DOLLARS"
          " ;E; "DOLLARS"

          >t;D; DOLLARS
          "    "
           ;Y8; DOLLARS
COSTS    (continued)

3370 ?RINT"TOTAL PURCHASED  EOUUIPMENT COST";P;"DOLLARS"
3360 PRINT'"TOTAL INSTALLED  EQUIPMENT COST" ;T ; "DOLLARS"
3390 LET B=  . 2*T
34CO LET F=.08*1?'FREIGHT  AND TAXES
3410 LET C=  . i'/i.V--T' CON STRUCT ION
3420 LET E=.10*T'ENGINEERING
3430 LET D=T+B+F+C+E
3440 LET Cl=.lb*D'CONTINGENCY AND CONTRACTORS  FEE
3442 LET Y£= . 15*(D+Cl)
3450 PR INT"BUILDING COST
3460 PRINT "FREIGHT AND TAXES
3470 PRINT"CONSTRUCTION  COST
3480 PRINT"ENGINEERING COST
34 SO PRINT
3500 PRINT "DIRECT PLANT  COST
3510 PRINT"CONTINGENCY AND  CONTRACTOR FEE  ";C1;  DOLLARS
3520 PRINT
3530 PRINT"FIXED CAPITAL  INVESTMENT        ";D+ci;"DOLLARS
3540 PRINT
3544 PRINT"WORKING CAPITAL
3550 PRINT
3560 PRINT"****************MANUF AC-TURING COST*********************
3570 LET A=(A1+A4)*32'COST  OF ACID
3580 LETL= (A3-A5)/9S*100*12'COST OF LIME
3590 LET W=  G3/.12'TONS  OF  WATER UESED
3600 LET W2=W*2000/62.4/.134'GALS
3610 let w3=w2/1000*.25'cost of water
3620 LET 03=01*0.1'OIL  COST
363CLET K=0
3640 FOR 1=  1  TO 22
3650 LET H=  H+K(I)
3660 NEXT I
3670 LET E=E*24*.7487'KILOWATT HOURS
36SOLE1 E1=S*1.25*.010'COST PER DAY WITH 25% SURPLUS
3690 LSI Li=3*3*24'LABOR 3 MEN 24ER AT  3.00
3700 LET L2=3.5*1*24'SUPERVISION
3710 let f=.15*(ll+12)'fringe benefits
3720 LET M=(D+C1)*. 05/360 'MAIN AND REPAIRS AT 5% OF FCI
3730 LET S=.15*M/2'SUPPLIES  15% OF  MAIN
3740 LET Fl=.02':i-(D+Cl)/360'TAXES 2 % OF FCI
3750 LET F2=.01*(D+C1)/360'INSURANCE
3760 LET P = .15*(Ll+L2+M/2)'PAYROLL OVERHEAD
3770 LET'P2= P'LAB  WORK
3780 LET P3=.5*(Ll+L2+M/2)'PLANI OVERHEAD  AT 50% OF LABOR
379C FRINT"INPUT DUMPING FEE PER TON"
3800  inputMdl
3810 print"input cost for disposal of waste per ton"
3820 INPUT D2
3830 PRINT"INPUT INTEREST RATE AND YEARS OF OPERATION"
3640 INPUT R1.R2

-------
                                  -134-
         (continued)
CCS13
3£42 LET C2=(Rl*( l
3«?50 LET C=C2*(D+C1+Y8)/3&0
3S6G REM CAPITAL  RETURN
3870 let t=a-;-l+w3+o3+el+ll+12+f+m+s+f
3&SO LEr: T=T+D2-''E9
3900 PRINT 'RAW MATRIALS(<
3910 PRINI "ACID" .A.1+A4, "TONS/DAY" , A
3920 PRINT"LIME", (A3-A5)/96*ioo, "TONS/DAY ,L
3930 PR INT "UTILITIES"
39*0 PR I NT " WAT ER " , W 2 f " G AL £ " , W 3
3950 PRINT "ELEGI".?,, "KILOWATTS", El
3960 print "oil" ,01 , "gal" A0l*0 . 1
3970 PR INT "WASTE 'DISPOSAL  , E9, "TONS/DAY" ,D2*E9
39&o PRIKT"LAEOR" . 72 , "HRS" ,LI
3990 PRINT;; SUPER", 24, ;;KRs;;,L2t,
4000 print FRINGE BEN  ,   ,    , f
4010 PRIMT"y.AIMTAIN" ,Z9,Z9,M
4020 PKINT"SUPPLIES" ,z9,z9,s
4025 PRINT"FIXED CHARGES"
4030 PRINT"TAXES",Z9i,Z9,Fl
4040 PRIN'l"lNSURAKCE"J(iZ9,Z9|,F2
4050 print" cap return  ," ",   ",c
4055 PRIKT/'GENSRAL COST"
4060PRINT"PAY OVER" , Z9,Z9 ,P
4070 ?RINI"LAB" ,Z9,Z9,,P2
4oso PRIKT"?LANT OVER  ,Z9,Z9,P3
4090 PRINT
4095 ?RINT"TONS /DAY OF GLUCOSE" ;G3
4100 PRINT "TOTAL COST/DAY  NO DUMP FEE
4110 PRINT
^120 PRIXT"COST/TOX OF  GLUCOSE NO DUMP
4130 ?RI:^"CO£T/L3 0? GLUCOSE NO DUMP
4140 PRINT
4145 PRINT "TOTAL COST /DAY  WITH DUMP FEE
4150 PR INT "COST /TON WITH DUKP FEE
41 60 PRINT "COST/L3 WITH DUMP FEE
4165 GOTO 51 &0
41 66 KEK*-*-"-~**-*w*****EVAPORATOR CALCULATION******************
4170 LET  N-6
41£0 DIM  3(7,7),W(7.1).F(7.1).R(7.7)
4190 /.AT  E=ZER
4270 FOR  1=  0 TO N
42SO READ  T(l),L(l)
4290 L7.1  X(I)=T(I)
4300 NEXT  I
4310 LET  C1=G3/N7
4320 LET  C2=.12
4330 LET  ?=  N7---2000/24
4340 FOR  1=  1 TO  N-t-1
                                           ;T; "DOLLARS
                                                 DOLLARS
                                           ;T/G3/2000; DOLLARS

                                          " ;Ti; "DOLLARS"
                                          " ;T1/G 3 ; "DOLLARS"
                                          " ;T1/G 3/2000 ; "DOLLARS*'

-------
                                 -135-
COST3

4350
4360
4370
4390
4381
4400
4410
4420
4430
4440
4450
4460
4470
4480
4490
4500
4510
4520
4530
4540
4550
4560
4570
4580
4590
4600
4610
4620
4630
4640
4650
4660
4670
4680
4690
4700
4710
4720
4730
4740
4750
4760
4770
4780
4790
4600
4810
4820
4830
4840
    (continued)

READ U(I)
NEXT I
LET G=(X+v:l)*2000/24
DATA 350,870,327,889,304,905,282,924,260,939,240.952,212,970
DATA 500,480,450,410,370,250,500
LET WO=F
LET S8=F*C1'SOLIDS  IN  FEED
LET P=SS/C2'PRODUCT RATE
LET E= WO-P' LBS/KR EVAPORATED IN TOTAL  SYSTEM
FOR 1= 1 TO N
LET T(I)= X(I-1)-X(I)
NEXT I
LET B(l,l)= L(0)
LET B(l,2)= -L(l)
    B(l,3)=0
LEI
LET B(l,4)=0
LET B(2,l)=0
LET B(2,2)= L(1)-T(2)
LET B(2,3)=-L(2)
LET B(2,4)=0
LET B(3,l)=0.
LET B(3,2)= -T(3)
LET B(3,3)=L(2)-T(3)
LET E(3,4)=-L(3)
IF N>3 THEN 4640
LET B(4,l)=0
LET B(4,2)=l
LET B(4,3)=1
LET B(4,4)=l
LETF(N+1,1)=E
FOR 1= 1 TO N
LET F(1,1)= -WO*T(I)
NEXT  I
IF N=3 THEN 4810
FOR J=4  TO N
LET B(J,1)=0
FOR 1= 2 TO J-l
LET B(J,I)=-T(J)
NEXT  I
LET B(J,J)=L(J-1)-T(J)
LET B(J,J+1)=-L(J)
NEXT  J
LET B(N+1,1)=0
FOR 1= 2 TO N+l
LET B(N+1,I)=1
NEXT  I
KAT R= INV(B)
MAT W= R*F
 REM  CALCULAT  AREAS
FOR 1= 1 TO N

-------
                                 -136-                           i    •*
COSTS    (continued)

<650 LET A(I)= W(I,1)*L(I-1)/(U(I)*T(I))
4860 NEXT I
4870 LET G2= W(N+1, 1 )*L (N )/140
48SO LET T4= 212-70
4890 LET T5 = 2
4900 LET T6= (T4-T5)/(LOG(T4/T5) )
4910 LET A(N + 1)=W(N+1,1)*L(N)/(U(N + 1)*T6)
4920 PRINT
4930 PRINT
49^0 FOR 1= 1 TO N
4950 LET Z8=Z8+W(I,1)*X(I-1)
4960 LET Z7=Z7+W(I,1)
4970 NEXT I
49fQ LET Kl=(Z84.W(7,l)*212+P*212)/(Z7+W(7.1) + P)
5050 LET S(22)=(X+Wl)*2000/62.4*2/24/60
5055 LET K2=(W*V9*2000/24-W(ltl))*870/((X+Wl)*2000/24)
5056 LET K4=K1+K2'F DEG  INTO HEATER
5C57 LET Y-0
5080 FOR 1= 1 TO N
5090 LET Y= Y+A(l)
5100 NEXT I
5110 LET Y2= Y/N
5152 LET S(20)=Y2
5153 LET S(21)=A(N+1)
5157 RETURN
5160 END
 yo 651

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