«>EPA
            United States
            Environmental Protection
            Agency
            Industrial Environmental Research EPA-600/7-80-103
            Laboratory         May 1980
            Cincinnati OH 45268
            Research and Development
Wood Waste as a
Power Plant
Fuel in the Ozarks
            Interagency
            Energy/Environment
            R&D Program
            Report

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                 RESEARCH REPORTING SERIES

 Research reports of the Office of Research and Development, U.S. Environmental
 Protection Agency, have been grouped into nine series. These nine broad cate-
 gories were established to facilitate further development and application of en-
 vironmental technology. Elimination of traditional grouping was  consciously
 planned to foster technology transfer and a maximum interface in related fields.
 The nine series are:

       1.  Environmental Health Effects Research
       2.  Environmental Protection Technology
       3.  Ecological Research
       4.  Environmental Monitoring
       5.  Socioeconomic Environmental Studies
       6.  Scientific and Technical Assessment Reports (STAR)
       7.  Interagency Energy-Environment Research and Development
       8.  "Special" Reports
       9.  Miscellaneous Reports

 This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT
 RESEARCH AND DEVELOPMENT  series. Reports in this series result from the
 effort funded under the 17-agency Federal  Energy/Environment Research and
 Development Program.  These studies relate to EPA's mission to protect the public
 health and welfare from adverse effects of pollutants associated with energy sys-
 tems.  The goal of the Program  is to assure the rapid development of domestic
 energy supplies in an environmentally-compatible manner by providing the nec-
 essary environmental data and control technology. Investigations include analy-
 ses of the transport of energy-related pollutants and their health and ecological
 effects; assessments of, and development of, control technologies for energy
 systems; and integrated assessments of a wide range of energy-related environ-
 mental issues.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.

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                                      EPA-600/7-80-103
                                      May 1980
     WOOD  WASTE  AS  A  POWER  PLANT  FUEL

               IN THE OZARKS
                     by
               V.  J.  Flanigan
     Mechanical Engineering Department
       University  of  Missouri  -  Rolla
           Rolla,  Missouri   65401
           Grant No. R804270-010
              Project Officer

               Harry Freeman
        Incineration Research Branch
   Industrial Pollution Control Division
Industrial Environmental Research Laboratory
          Cincinnati, Ohio  45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
     OFFICE OF RESEARCH AND DEVELOPMENT
    U.  S.  ENVIRONMENTAL  PROTECTION AGENCY
           CINCINNATI, OHIO   45268

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                          DISCLAIMER
     This report has been reviewed by the Industrial Environmen-
tal Research Laboratory-Cincinnati, U. S. Environmental Protec-
tion 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 trade names or commercial products constitute endorse-
ment or recommendation for use.
                              11

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                           FOREWORD
     When energy and material resources are extracted, processed,
converted, and used, the related pollutional impacts on our
environment and even on our health often require that new and
increasingly more efficient pollution control methods be used.
The Industrial Environmental Research Laboratory-Cincinnati
(lERL-Ci) assists in developing and demonstrating new and
improved methodologies that will meet these needs both efficiently
and economically.

     In an attempt to solve the problem of wood waste disposal,
the study described here was initiated to study the possibility
of using the waste as a supplement to present coal fire facili-
ties.  The overall goal was to promote the economic and energy
conservation and pollution free characteristics of this material.
This report will be of interest to those considering supplementary
coal with wood chips.  Requests for further information should
be addressed to the Incineration Research Branch, lERL-Cincinnati.
                              David G. Stephan
                                 Director
                 Industrial Environmental Research Laboatory
                                Cincinnati
                               iii

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                           ABSTRACT


     The report discusses the testing program conducted on a
chain-grate stoker boiler with a blended coal and wood waste
fuel.  The boiler was designed to produce 18,000 Ib/hr  (8,200
kg/hr) of saturated steam at 150 psig (103.4 N/cm2).  The
objective of the tests was to determine the difference, if any,
in the performance and the emissions of the boiler co-firing
wood and coal as compared to firing coal alone.  Four different
coals with different sulfur contents were fired with the wood
waste.  The wood waste content was varied up to 2/3 by volume.

     Particulate loadings, opacity and concentrations of sulfur
dioxide, nitrogen oxide and total hydrocarbons in the flue gas
were measured.  Also, cyanide concentrations and particulate
polycyclic organic emissions were determined for some of the runs,
The baseline for all data comparisons was obtained by running
the boiler with a particular pure coal.

     The boiler performance was reported by plotting the boiler
efficiency as a function of the wood percentage in the fuel and
by plotting a performance index defined to be the pound of steam
produced per pound of fuel fired versus weight percent wood.  The
efficiency curve showed a slight increase with increasing wood
content while the performance index naturally decreased due to
the lower heating value of the wood.  The performance index was
used to predict the operational savings from supplementing the
coal with the wood waste.

     Results indicate that particulate and nitrogen oxide
emissions are not substantially altered by using wood waste as
supplemental fuel with coal for the test conditions adopted in
the program.  Sulfur dioxide emissions decreased with increased
proportions of wood waste in the coal-wood mixture, whereas total
hydrocarbon concentration increased when wood waste content was
increased.   Cyanide concentrations were not substantially
affected by substitution of wood waste for coal; particulate
polycyclic organic emissions were below the detectable limits for
all fuels used in the tests.
                               IV

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                           CONTENTS
Foreword	iii
Abstract	iv
Figures	vi
Tables	viii
Abbreviations and Symbols  	  ix
Acknowledgment 	  xi

   1.  Introduction  	   1
   2.  Conclusions 	   3
   3.  Recommendations 	   5
   4.  Materials and Methods 	   6
            Fuel Characteristics 	   6
            Fuel Availability  	   8
            Fuel Handling	13
            Fuel Firing	15
   5.  Experimental Procedures 	  22
            Fuel Test  (MRI)  	22
            Sampling and Analysis Methods  	  2<
   6.  Results and Discussion	28
   7.  Experimental Procedures 	  46
            Fuel Testing (UMR)	46
            Analysis	48
   8.  Results and Discussion	52

References	67
Appendices

   A.  Facilities Statement  	  69
   B.  Data Collected and Calculated	70
   C.  Report of Analysis	73

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                            FIGURES


Number                                                      Page

   1  U.S. Forest Service Regions for Missouri 	   9

   2  Fuel Handling Diagram  	  14

   3  Boiler Sketch  	  16

   4  Boiler Modifications 	  19

   5  Fuel Supply Sketch	20

   6  Power Plant Breeching System 	  23

   7  Section of the Sampling Location 	  25

   8  Particulate Loading as a Function of the
        Excess Air	43

   9  Particulate Correction as a Function of Weight
        Percent Coal	44

  10  Sulfur Dioxide Emissions as a Function of Fuel
        Blend and Coal  Sulfur Content	53

  11  Normalized Sulfur Dioxide Output as a Function
        of Wood Percent	54

  12  Nitrogen Oxides Emissions as a Function of
        Fuel Blend	55

  13  Opacity of Flue Gas as a Function of Excess
        Air and Coal Sulfur Content	56

  14  Opacity as a Function of the Weight Percent
        of the Coal	57

  15  Opacity Correction Curve as a Function of the
        Weight Percent  Coal	59

  16   Dry  Gas and Unburned  Combustible Losses as a
        Function of Fuel Blend	60
                              VI

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Number                                                      Page

  17  Moisture Losses Due to Fuel Hydrogen, Air
        Moisture, and Fuel Moisture as a Function
        of Fuel Blend	61

  18  Net Efficiency Excluding Radiation and Unac-
        counted Losses as a Function of Fuel Blend	62

  19  Performance Factor (Pound Steam per Pound Fuel)
        as a Function of Fuel Blend	63

  20  Economic Results from the Blended Fuel Use	66
                              VI1

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                            TABLES


Number                                                      Page

   1  Percentage of Sulfur Contents on the Dry Basis ....   6

   2  Fuel Ultimate Analysis (% by weight) and
        Heating Values (Dry Basis) 	   7

   3  Residue Production Pounds per Year 	   8

   4  Missouri Forest Products Industries Near
        Rolla, MO	11

   5  Test Results (Uncorrected)	29

   6  Test Results (Corrected)	35

   7  Comparison of Measured and Calculated Flue
        Gas Flow Rates	41

   8  Comparison of 1974 Compliance Test with Coal-Only
        Results of Current Programs  	  45

 B-l  Test Data	70

 B-2  Test Data Plotted	71
                             Vlll

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                   ABBREVIATIONS AND SYMBOLS
SYMBOLS
A      — Weight percentage of ash in the net fuel fired
C      — Weight percentage of carbon in the net fuel fired
C      — Weight percentage of carbon actually burned in the net
            fuel fired
FR     — Fuel firing rate
G      — Volume ratio of wood to coal in the blended fuel
H_     — Weight percentage of hydrogen in net fuel fired
H      — Weight percentage of hydrogen in coal
 G
H      — Weight percentage of hydrogen in wood
 Wf
HHV    — Dry higher heating value of coal
   C
HHV_   — Dry higher heating value of net fuel
HHV    -- Dry higher heating value of wood
   WF
L      — Loss due to moisture in air
 r\
L      — Loss due to dry flue gases
L-.     — Loss due to hydrogen in fuel
 ri
L      — Loss due to moisture in fuel
 m
L      — Loss due to unburned combustible in refuse
M      — Weight of coal added along sides of stoker
MF     — Weight of blended fuel fired
MC     — Moisture content of coal
  c
MC     — Moisture content of wood
  w
MW     — Molecular weight of flue gas
N_     — Weight percentage of nitrogen in net fuel fired
0_     — Weight percentage of oxygen in net fuel fired
0      — Weight percentage of oxygen in coal
 G
0      — Weight percentage of oxygen in wood
 Vr
P      — Pressure
R      — Ideal gas constant
                              ix

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 S        —  Weight percentage of sulfur in  net fuel  fired
 S _       —  Weight percentage of sulfur actually  burned  in  net
               fuel fired
 T        —  Temperature
 T        —  Air  temperature
 T        —  Flue gas  temperature
 V—  Actual volume  of  dry flue  gas per  100 pounds of fuel
 VAIR     —  Actual volume  of  air entering boiler  per pound  of
               fuel
 V.™       —  Theoretical  dry flue gas volume per 100 pounds  of
  Ci            fuel
          —  Average volume of excess air per 100  pounds of  fuel
 VEA|      —  Volume of  excess  air per 100 pounds of fuel from
     C02        carbon dioxide  analysis
 vEA|o     —  Volume of  excess  air per 100 pounds of fuel from
     2         oxygen analysis
 V        —  Volume of  nitrogen in theoretical  air per 100 pounds
  iN            of fuel
 V n       —  Volume of  oxygen  in  theoretical air per 100 pounds
               of fuel
 WDG       —  Weight of  dry  gas per pound of  fuel
 WH       —  Weight of  moisture per pound of fuel
 W        —  Weight of  air  moisture per pound of fuel
 WF       —  Weight fraction of coal in blend
 x         —  Weight ratio of wood/weight of  fuel
 y         —  Weight ratio of coal/weight of  the fuel
 Z         —  Weight percentage of  a constituent  (excluding oxygen,
              hydrogen) of net fuel fired
 Z         —  Dry weight percentage of a constituent (excluding
              oxygen, hydrogen) of coal
 Z         —  Dry weight percentage of a constituent (excluding
              oxygen, hydrogen) of wood
 %C02      — Volumetric percentage of carbon dioxide from Orsat
 %02       — Volumetric percentage of oxygen from Orsat
 3         — Weight  fraction of carbon in the refuse
Y         — Weight  fraction of sulfur in the refuse
 p        — Density of the constituent

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                        ACKNOWLEDGMENTS
     The author wishes to express his appreciation to the
Environmental Protection Agency for the financial support of this
project and to Mr. Harry Freeman for his help and guidance during
the tenure of the project.

     The author also would like to thank the Chancellor for his
encouragement and confidence in the work undertaken.  A special
thanks also goes to the power plant operating and maintenance
personnel who were always helping and to Elmer Doty, the graduate
student who assisted in obtaining the data.

     The author also thanks Art Spratlin and Jim Kelly of the
EPA regional office in Kansas City for the loan of the Method 6
sampling equipment, which greatly helped in the testing.
                               XI

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                         INTRODUCTION
     The report defines the experience at the University of
Missouri-Rolla with a boiler fuel, which consisted of a blend of
wood residue and coal.  This study was undertaken to save an un-
renewable resource, coal, and at the same time conserve energy
by using a waste product.

     The conversion of waste products to energy has become an
attractive and necessary means of disposing of waste material.
The success of this expedient was attested to by the programs at
Union Electric in St. Louis, Mo.  (1), and the program in Ames,
Iowa (2).  The facilities both burned solid waste derived fuel to
produce electricity.  The wood industry in the Northern States of
the U.S. has long used waste wood as an energy source.

     The wood industry in the state of Missouri is represented by
approximately 500 sawmills, most of which are too small to use
their waste as an energy source, but the waste represents a huge
amount of material and a severe problem.  The problems arise from
the danger of fires in the stockpiles, difficulties with run-off
and simply the large amount of land required.  Previously, the
waste was simply stockpiled or burnt in a teepee burner, but
neither of these options are presently satisfactory, leaving the
operator with the thoughts of land-filling the material.  The
land-fill solution becomes especially critical when one examines
how depressed the industry has been and how important it is to
the states' economy.

     With these facts one immediately begins to consider the
energy content of the waste and its value as a fuel.

     The University of Missouri-Rolla is located at the edge of
the Eastern Ozark Region, the most heavily forested area of the
state.   At this location, the University has been investigating
the possibility of using wood waste to fuel their central power
plant,  which provides the heating and cooling load for the
campus.

     The estimated coal need at the plant for FY 1977-78 was
12,000 tons at an estimated cost of approximately $450,000.  A
savings here would be of great benefit to the University and the
people of the state.  The coal normally used in the plant is an
Illinois blend of high and low sulfur coal providing a maximum
sulfur content of 2%; the wood was a hardwood blend mostly oak

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with zero sulfur content.

     The primary objective of this report is to present and dis-
cuss experimental results obtained from the monitoring of the
flue gases and the performance characteristics of a boiler fired
with blends of coal and hardwood waste (primarily oak chips).
The research was performed using a boiler located in the
University of Missouri-Rolla Power Plant from January through
August 1977.

     Results are presented for sulfur dioxide emissions, nitrogen
oxides and particulate effluents.  The gaseous pollutants,
presented as weight per unit energy input, are treated as a
function of both the sulfur content of the coal and the weight
percentage of wood in the fired fuel.  Particulate effluents are
presented as opacity and particulate versus percent excess air
and weight percent coal.

     The report also discusses potential hazardous organic
materials that may be omitted with the use of wood waste.

     The boiler performance was addressed in terms of the boiler
heat balances for the different blends of each of the coals.  The
overall efficiency of the unit was obtained from this data for
each run providing the data necessary to suggest a yearly cost
with that particular fuel blend.   The blended fuel costs were
compared to the all coal operating cost and the dollar savings
presented.

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                          CONCLUSIONS
     In this investigation, the relative performance of coal and
coal/wood blends as fuel was investigated experimentally.  The
conclusions arising from this work are as follows:

     1.  Wood waste burned in conjunction with coal exhibits heat
         losses that vary as predicted, and result in relative
         efficiencies somewhat higher than pure coal.  Simply
         stated, the utilization of the heat released per unit
         weight of fuel is slightly improved.

     2.  The performance factor tended to decrease slightly with
         the addition of wood to the blended fuel.  Whether or
         not this decrease is significant depends on the size of
         the plant and the extenuating economic factors.  For
         this particular unit, the use of a composite coal/wood
         fuel appears as an attractive proposition.  In fact,
         savings of up to $35,000/year were suggested with large
         decreases in the coal used.

     3.  The boiler response is affected by the blended fuel.
         The boiler cannot respond to a change in load in the
         same sense as when firing all coal.  The blended fuel
         requires more attention and skill from the fireman.

     In this report, the emission characteristics of various
blends of coal and hardwood waste were also investigated experi-
mentally in conjunction with the boiler performance.  The
conclusions arising from this work may be stated as follows:

     1.  Sulfur dioxide emissions expressed unit weight per unit
         heat input were shown to be measurable with a relatively
         high degree of accuracy.  Emissions decreased as
         expected when the wood content of the blend was
         increased.  In fact, the sulfur dioxide emissions may
         be satisfactorily approximated from the sulfur content
         and the heating value of the coal.

     2.  Emissions of nitrogen oxides were not visibly dependent
         on the wood to coal ratio of the fired fuel.  However,
         the lack of flame temperature data does not permit
         complete resolution of these effects.

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3.  The examinations of the particulate emissions and
    opacity data for the different, fuels, with the correc-
    tions for excess air, point out that the particulate
    wasn't substantially altered by the use of the wood
    waste.  This conclusion was based on the zero slope of
    the corrected opacity data and the slight decrease in
    the particulate data with increased coal content.  The
    opposite slope of the opacity data (uncorrected) as
    compared to the particulate data also leads to this
    conclusion.

4.  Total hydrocarbon concentrations increase with increased
    substitution of wood waste for coal.   For coal-only
    tests, hydrocarbon emissions averaged 4.25 ppm, and for
    one volume wood waste plus one volume coal, hydrocarbon
    levels were 6.2 ppm.  When two volumes wood waste were
    used with one volume coal, the average hydrocarbon
    emissions were 8 ppm.

5.  Cyanide concentration was not substantially affected by
    substitution of up to approximately 50% of coal with
    wood waste.

6.  Particulate Polycyclic organic emissions were below
    detectable limits for all fuels used.

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                        RECOMMENDATIONS


     It is recommended that from the results of this study the
University consider firing one of the two small boilers on a
blended fuel.  It is recommended that the firing be on the con-
tinuous basis and for a period of one year.

     In order to reduce the difficulties experienced with
ignition problems, high stoker speeds, high gate settings, and
slow response the University should consider a higher energy
blend.  A blend of 20% by weight wood, 39% by volume, would be
a possibility.  The blend suggested would still provide a 12%
savings in fuel cost and would provide the higher Btu content per
pound of fuel.

     The demonstration of an extended operation on blended fuel
at some reasonable boiler load would provide valuable operating
data, including the demonstration of any slagging and ash prob-
lems, if they exist.  The demonstration would also provide
emphasis to encourage other users to study the possibilities of
adapting wood waste to their combustion system.

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                      FUEL CHARACTERISTICS


      The fuel used consisted of either a pure coal or a blend of
 wood and coal,  a requirement of boilers equipped with chain-
 grate stokers.   The operating instructions of these stokers
 state a requirement of a minimum of a 6 to 7% ash content in the
 fuel used.   The ash content of the wood chips was less than 1%,
 and required that the chips were always blended with the higher
 ash coal.   This ash requirement provides protection for the
 moving chain from the radiant energy of the fire.

      The stoker's manufacturer also recommended these stokers
 for a wide  range of screened bituminous coals,  suggesting a
 maximum 1 inch  top size and a minimum of 28 mesh for fines.  The
 coal normally used at the plant is a blended Illinois coal
 normally providing a 2% sulfur content on the as received basis.
 A sample screen test and proximate analysis of  the blended coal
 is given in Appendix C.  This analysis meets the coal specifica-
 tions suggested by the manufacturer.

      The coal used in the test program was as follows;  the normal
 blended Illinois coal,  Ziegler coal,  Orient coal, and River King
 coal.   The  blended coal normally used was a blend of 60% Orient
 and 40% Ziegler.   The sulfur content of these fuels is given in
 Table 1.  The ultimate analysis for these coals and the wood,
 as measured by  an industrial laboratory,  is given in Table 2.


	TABLE 1.   PERCENT SULFUR CONTENTS ON THE  DRY BASIS	


 Orient   Ziegler    Blended (Orient & Ziegler)     River King

  1.91       3.12                  2.44                   3.29
     The wood used for the most part was hardwood chips.  The
chips on an average were 1 inch square by  1/8 inch thick
(6.54 cm? x 0.3174 cm).  They were produced by chipping debarked
slabs of mixed hardwoods.  The sulfur content of course was very
low, typically zero, though the laboratory analysis reported
some trace of sulfur in the wood fuel.  Other fuels used on a
limited basis were sawdust and bark.  The bark was the result
of the debarking of the hardwood logs and contained a large
percentage of wood fiber.  The bark's size distribution was

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      TABLE 2.   FUEL ULTIMATE ANALYSIS (% BY WEIGHT)  AND
                HEATING VALUES (DRY BASIS)
           Blended
          Coal No. 1
 Ziegler
Coal No. 2
  Orient
Coal No. 3
River King
Coal No. 4
Wood
Carbon
Hydrogen
Oxygen
Nitrogen
Sulfur
Ash
Higher Heat-
ing Value
Btu/lb
MJ/KG
72.515
4.957
8.560
1.585
2.444
9.939


11,830
27.5
69.114
5.227
6.997
1.176
3.120
14.366


12,560
29.2
71.955
5.104
9.706
1.477
1.911
9.847


12,680
29.5
67.67
4.4
11.04
1.02
3.29
11.98


12,633
29.4
50.18
5.06
43.00
0.30
0.15
1.31


8,770
20.4
typically a mixture varying from long fibers of approximately 3
inches (7.62 cm)  to a considerable concentration of fines.  The
sawdust was all fines and the dust was collected off the header
saw in the mill.

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                        FUEL AVAILABILITY
      Looking at the Missouri Sawmills,  it is of interest to note
 that approximately 50% of the incoming  log ends up as sawdust,
 edgings or possibly bark or chips,  depending on the mill.   The
 waste percentage was taken from the work accomplished by the
 Missouri Conservation Department for Missouri Sawmills (3).  Of
 course the actual percent of waste  was  dependent on the size of
 the logs,  material to be produced,  and  the actual mill operation.
 To give an indication of the availability of wood waste a  survey
 of existing stock piles and annual  production of wood waste in
 the Eastern Ozark Region of the State was taken (4).

      The Eastern Ozark Region,  shown in Figure 1,  is  the most
 heavily forested area of Missouri.   The figure was taken from
 the NCFES bulletin,  U. S.  Forest Service, USDA, 1972  (5).   The
 percentage of forested area is  given below the name of each
 region in Figure 1.

      This Eastern Ozark Region  is naturally the area  representing
 the most active forest industry in  the  state.   The survey  not
 only looked at the residue from the mills,  but also from
 manufacturing operations like pallet plants,  flooring mills,
 etc.   The annual production for this region was 1,764,563,000
 pounds of  residue,  broken  up as in  Table 3.
              TABLE  3.  ANNUAL  RESIDUE  PRODUCTION
	EASTERN OZARK REGION  (pounds)	


               Sawdust               571,800,000
               Trim                  82,210,000
               Shavings              70,200,000
               Slabs/Edgings         882,080,000
               Bark                  154,400,000
               Shreds                 3,860,000

               Total               1,764,550,000



     This represents an annual  production of  10,587,300 x  10
Btu, based on a Btu content of  6,000 Btu/lb,  and amount to
880,000 tons.  At the same time, in  just this region,  there are
2,317,880,000 pounds  (1,150,000  tons) of residue existing  in


                                8

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                               PRAIRIE REGION
                                 9% For res ted

                                      r--—,
MISSOURI
FOREST SURVEY  REGIONS
vo
                                      N—NRIVER BORDER
                                         /   REGION
                                    |~-T~'     26
                           NORTHWESTERN OZARKS
                                REGION  38 %
                                   UNIVERSITY.
                                 SOUTHWESTERN
                                 OZARKS REGION
                                      42%
       Figure 1.   U.S. Forest Service Regions  for Missouri
                  (Courtesy of North Central Forest Experiment
                  Station, Forest Service,  USDA)

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 dumps and stockpiles.   The Residue specialist for the Conserva-
 tion Commission approximated that another 1,500,000 tons are
 produced annually in the other regions of the state.   The total
 quantity of waste comes to some 2,400,000 tons.   The  tonnage does
 not consider residue in the woods in so far as 50% of the tree
 is  left in the woods as slash.   A portable chipper and skidder
 could quickly convert the slash to chips and at  the same time
 remove poor quality timber for stand improvements (6).  The
 portable chipper system could provide even larger quantities of
 available Biomass.   Even though the developers and users of
 these total tree harvesting systems need to exercise  care in
 their use because of the problems and the lack of understanding
 in  regards to the nutrient removal (7)  from the  soils.  This
 care is especially critical in clear cutting operations.   The
 Biomass was definitely available in residue form for  this
 experiment,  but it was also apparent that much more was  available
 in  the way of slash and cull timber if a need could be
 established.

      Further documentation of the available wood waste in this
 area can be derived from wood industry data.   The first  consider-
 ation might be the sawmill sizes and production.   In  1975 the
 Missouri Department of Conservation published the following
 sawmill distribution (8);
           Production per year          Number of Sawmills

    Under 100 Million Board Feet               152
      100 MBF -   249 MBF                        99
      250 MBF -   499 MBF                        77
      500 MBF -   749 MBF                        41
      750 MBF -   999 MBF                        24
    1,000 MBF - 1,999 MBF                        68
    2,000 MBF - 2,999 MBF                        33
    3,000 MBF - 3,999 MBF                        10
    4,000 MBF - 4,999 MBF                        5
    5,000 MBF - 7,499 MBF                        3
    7,500 MBF - and greater                    	3

                                               517
     University of Missouri-Rolla1s location as a potential user
was also established through the following mileage table  (9)
(Table 4).  The table shows the concentration and activity of
the wood industry in the area surrounding the University.

     In this work, only the available fuel at the sawmills was
used.  The wood chips were obtained from the Reed Lumber Co.,
approximately 60 miles from Rolla.  They were delivered in dump
bed trailer trucks at a cost of $12.50/ton.  Typically the wood


                              10

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         TABLE 4.   MISSOURI FOREST PRODUCTS INDUSTRIES
                   NEAR ROLLA,  MISSOURI
         WITHIN X MILES
         Key:
                    TOTAL AND
                TYPE OF  INDUSTRIES


50
40
30
25
20
10
A
63
40
25
22
9
5
B
15
9
2
1
1
1
C D
9 1
6
6
5
3
— —
E
1
1
1
1
—

             A  Sawmills (100,000 board feet per year minimum)
             B  Pallet Plants
             C  Stave Mills
             D  Heading Mills
             E  Flooring Mills
chips are hauled in standard cargo trailer but the University
doesn't have unloading facilities for the trailers.  With this
in mind, the bid requested they be hauled and delivered in a
self-unloading trailer.  This requirement added to the price of
the product and also restricted the bids to those people having
self-unloading equipment.

     Since the time of the bid for the wood chips, the industry
has started using trailers with live bottoms.  They are much
cheaper than the dump beds, and their use could lower the
delivery price for the wood chips.  The wood chip price, as
suggested by the Green Mountain Study (7), was $10 to $15/ton
projected so the cost was in the proper range.

     At the same time, bid prices for bark delivered in the same
fashion were obtained by the University.  They were $3.90 ton/
delivered.  The hauling distance was approximately 45 miles.

     The coal used in the study, as well as the coal used in the
everyday running of the plant is delivered by self-unloading
trucks.  The coal is pre-blended in St. Louis and delivered to
Rolla ready for use.  The coal cost is $37.53/ton.  The cost of
the fuels per million Btu was;
     coal
     wood chips
$1.56/10b Btu
$1.04/106 Btu
                               11

-------
     bark        $0.35/106 Btu

If the wood could be used with approximately the same efficiency
as the coal, the potential for savings is pointed out in the cost
per unit energy quantity given.  The efficiency and firing
characteristics are defined in the preceding chapters.  The
availability of the wood product discussed in this chapter seems
to be without problem.
                              12

-------
                         FUEL HANDLING


     Once the fuel, either coal or wood, is delivered, it is
stockpiled separately in the coal yard to be used as needed.
The fuel used for study was either coal or a blend by volume of
wood chips and coal.  The volume measure was simply the bucket
of the front-end loader used to transport fuel to the power
plant from the stockpile.  The initial preparation for a test
was the decision of the volume ratio to be used and the quantity
necessary for the test.  When the ratio was given to the front-
end-loader operator he obtained the necessary volumes of wood
and coal.  These volumes were dumped in an open area of the coal
yard and then the volumes were wind rowed.  The wind rows were
passed through several times to mix the fuel.  This operation
seemed to work well and there weren't any problems with in-
consistent blending, at least not in terms of the mixing
operation.

     The blended fuel was then moved to the coal pit where  it
was carried by a bucket conveyor to a segrated bunker in the top
of the plant.  The normal bunker, which has approximately a
60-ton capacity, was divided to allow for the storage of
approximately 15 tons of the blended fuel.

     At this point the fuel was available to the weigh lorry
of the plant to be weighed and supplied to the boiler as fuel.
This pattern of fuel handling is defined by the block diagram,
Figure 2.

     The weights of the fuel were defined from the volume ratios
and from weighing representative samples of the fuels.  The fuel
supplied was always weighed and records of these weights kept.
                               13

-------
Wood
SIorage
Loader
Blended
by
Volume
Front End
L oad er
Coat
Storage
                     Loader
                 Coal
                 Pit
                     Bucket

                     Conveyor
                Segrated
                Coal
                Bunker
                     Dump
                Weigh
                Lorry
                    Gravity
                    Chute
                Boiler
                Hopper
     Figure 2.  Fuel Handling  Diagram
                   14

-------
                          FUEL FIRING
     The power plant's function is to be a heating plant for the
University, supplying steam to heat and cool the buildings of
the campus.  The plant at one time was responsible for providing
both the electrical and heating needs of the campus and still has
that capability.  The plant's role was important to the project
because the test runs were only made when there was adequate
heating load.  The test boiler was always run in conjunction
with another boiler in the plant.  The two boiler combination
insured that a loss of boiler load on the test boiler would not
interrupt the campus heating system.  The two boilers also
required an increased plant load to adequately load both boilers.
This load condition restricted the testing to fixed periods of
time and weather.  A boiler load of greater than 5,000 Ib/hr
(2277 Kg/hr) was the goal in all the testing.

     All the tests performed were undertaken on boiler No. 2.
The No. 2 boiler was a small 18,000 Ib/hr  (8,200 Kg/hr), 150
psig (103.4 N/cm2), saturated steam boiler equipped with a
chain-grate stoker.  The boiler has no heat traps, superheaters,
or pollution equipment.  A sketch of the boiler is shown in
Figure 3.  The fuel was supplied by the fireman from the coal
lorry.   Before he dumped the fuel into the hopper of the boiler,
he weighed it and recorded the weight.  The fuel, which was in
the hopper, flowed onto the flat bed or chain as it moved into
the boiler.  The speed of the chain was determined by the steam
demand or, if the boiler was set to manual control, the speed
was determined by the stoker speed setting.  The energy supplied
to the boiler was completely a function of the speed of the chain
and the depth of the fuel bed, assuming that amounts of combus-
tion air were satisfactory.  The fuel bed depth was controlled
by the gate shown in Figure 3.  The operation manual recommends
a thick bed of fuel and a slow chain, but with the blended fuel
it could only be partially realized.  The situation was apparent
when an equivalent fuel bed of blended fuel was calculated from
a ratio using the normal coal bed thickness of 4  (10.16 cm) to
4.5  (11.43 cm) inches.  The calculation was made assuming the
same chain velocity for both fuels

             t   • L • HHV p
              c          cpc
      b   L  •  (HHV x + HHV y)p
                  c       wu  m
                               15

-------
            GATE
STEAM
      CHAIN
     AOITATORl
BLEND
    vV
 HOPPER
                      CHAIN DIRECTION
                       WATER
                                            ASH
                          AIR
                   Figure 3.  Boiler Sketch
                           16

-------
where:

     t,     - thickness of the blend bed  (in)

     t     - thickness of the normal coal bed  (in)

     L     - width of the chain  (in)

     HHV   - Higher Heating Value of coal (Btu/lb)
        c
     HHV   - Higher Heating Value of wood (Btu/lb)
        W
     x     - pounds of coal/pound of mixture

     y     - pounds of wood/pound of mixture, and

     P0/Pm - density ratio coal to mixture.
      \*>  III

For a blend of 1 wood by 1 coal, x was 72% and y was 28%, so t,
would be;


                 4" x 60" x 11,500 Btu/lb

     fcb = 60" x  (11,500 Btu/lb x .72 + 7000 Btu/lb x .28)

        =6.5 inches  (16.51 cm)                               (1)

     The boiler was limited to a 7-inch  (17.78 cm) opening of  the
gate so it was quite apparent that the gate was close to  the
limit of bed thickness.  For a fuel blended 2 wood by 1 coal,
the bed thickness would be;


                  4" x 60" x 11,500  (1§§°)
      b   60" x  (11,500 Btu/lb x 0.54 +  7,000 x  .46)

        = 8.23 inches

This thickness wasn't realizable so the  only other way  to
increase the energy input was to run the chain faster.   In  all
cases where the blend was used even with large gates  6  to 7
inches, the chain was always run faster  than with all coal with
a 4 inch gate.  The ignition of the fuel was provided by the
ignition arch  (Figure 3) of the boiler and the mechanism for
ignition was the radiant energy from the arch.   In the  operation
it was desirable to provide for ignition as soon as the fuel
flowed out from under the gate, but it was also  very  important
to keep it external from the gate itself.

     When the blend was first run with these high gates, the
results and experience pointed to ignition problems from both
the gate settings and the low ignition temperature of the wood.
The problem most frequently encountered  was burning under the
gate of the boiler.

     As one examines the ignition difficulties  it  is  apparent
that the problem was most pronounced in  the entrance  corners.

                              17

-------
 The burning under the gate would start in the corners and then
 spread to the total length of the gate.   There were probably
 several reasons for this.   One of the reasons was the boiler
 construction itself;  there was a point of stagnation in the fuel
 flow for gates above  5 inches.  This  point was on the entrance
 corners of the boiler as  the fuel flowed under the gate.   The
 ignition problem was  also  experienced with coal but not as
 frequently.   With this in  mind,  a modification was undertaken
 to  solve the problem  in the corners.   The boiler hopper was
 segrated by placing subdivisions in each end  of the hopper shown
 in  Figure 4.   This modification  provided three compartments:
 dimensions looking at the  front  of the boiler are 3 inches, 54
 inches,  and 3 inches.   The pure  coal  was placed in the outside
 compartments and the  blend in the middle compartment,  the fuel
 as  supplied to the boiler  would  look  like Figure 5.  With this
 fuel-firing pattern the corners  had pure coal with ignition and
 flow properties of coal.   As experience  was gained, coal  would
 only be fired in the  corners if  the fuel was  difficult to burn,
 quite often the corners would be fired with the blend or  left
 empty cooling the corner areas.

      Another problem  relating to the  ignition problem was the
 fuel bridging in the  boiler hopper.   The converging shape of  the
 hopper was fine for coal but was difficult for the flow of wood.
 As  the bridging occurred,  the fuel fell  away  from the  gate pro-
 viding a low energy input.   The  lack  of  fuel  on the chain also
 allowed  for  ignition  under the gate since it  wasn't sealed with
 fuel.   In order to prevent the bridging  condition,  a cam  shaft
 was  supported by bearings  across the  top of the hopper (Figure
 4).   This cam shaft was driven by a variable  speed,  3/4 horse-
 power electric motor  through a 10/1 speed reducer.   There were
 six  cams  on  the shaft  and  from each cam  a heavy chain  was hung.
 As the  shaft  rotated,  it provided the  chains  with a 1  1/4 inch
 travel.   The-chains were hung in the  fuel hopper providing
 agitation to  the  blended fuel.   The agitation prevented the
 bridging  in  the  hopper.  Again as experience  was gained the
 chains would  frequently not  be used, especially if  the fuel was
wet  and difficulty was  experienced providing  for the combustion
 air.

     The  firing was normally  started with a 6  to 6.5-inch gate
 setting and stoker  speed was  a function  of  the load desired.
The boiler was  always  fired with  the boiler controls in the
manual position.  With  manual  control, the  loading  was a  base
 load condition  requiring the  other boiler to  accept most  of the
 load swings.

     The  input  combustion  air  was  controlled  by the  fan and
locked into a  constant  setting.   The boiler was  equipped  with  a
force-draft fan and loovers on the intake  to  the fan controlled
the amount of  air.  At  the  same  time,   the damper on  the boiler
stack was closed more than when operating on  coal.   In

                               18

-------
       SIX CAMS-DRIVING

                    CHAINS
   fl
   BAFFLES
BLENDED
       FUEL
COAL
COAL
                             CHAIN
Figure 4.  Boiler Modifications
           19

-------
                  GATE
                    54"
COAU
                       BLEND
COAL
              CHAIN
          Figure 5.  Fuel Supply Sketch
                      20

-------
combination, the force-draft fan and damper were controlled to
maintain the boiler at the point where it would almost be at
zero gauge pressure.  This pressure was sensed by keeping the
boiler on the verge of smoking.  It typically related to a
pressure of -0.01 to -0.05 inches of H20 vaccuum.  With the
damper control, the fire could be moved away from and back to
the gate, but at the same time, opening the damper tended to
cool the boiler allowing for a loss of load.  The firing re-
quired a delicate balance between stoker speed, damper setting,
and gate height, and most of the time a less porous fuel bed
would have been desirable.  The excess air was almost always
high even when firing with pure coal.  The overfire air was
normally kept constant and didn't seem to strongly influence
the firing.

     Typically the fuel was dry and ignition very rapid.  The
fireman had to be very careful not to obtain ignition under the
gate or a very short fire with little ability to increase or
hold the boiler load.  As the fireman gained experience with the
fuel the firing problems tended to become easier to handle.
The boiler consultants made the measurements to cut a cam to
run the boiler system automatically but the cam was not
fabricated.
                               21

-------
            FUEL TEST  (MIDWEST RESEARCH INSTITUTE)
     A test program was undertaken to describe effects of the use
of blended fuel on the effluents and the efficiency with varying
blends and different coals  (10).

     The first test was undertaken during the last week of
January and the first week of February of 1977.  Field testing
was performed by Midwest Research Institute, field sampling team
to determine particulate, sulfur dioxide, and nitrogen oxide
emissions from the boiler firing the blended fuel and to identify
potential hazardous organic materials that may be emitted.  In
all cases, the goal was to determine if differences occurred in
boiler emissions from different blends and as compared to all
coal.

     For this series of tests, a high sulfur (>3%) coal (River
King) was fired alone to establish a baseline, and blends of wood
and coal in ratios of 1:1 (30% wood, 70% coal)  and 2:1 (46% wood,
54% coal)  by volume were compared to the coal baseline.  The
ultimate analysis of the coal and wood used for this test was
given in Table 2.

     The sampling of the unit was accomplished through the
breeching as shown in Figure 6.  Note the No. 2 boiler is
connected to the common breeching.
                              22

-------
ro
to
Breeching     \      Breeching

            Tranemissometer


     POWER HOUSE	
                                                                  I.D. FAN
                         Figure 6.  Power Plant Breeching System

-------
                  SAMPLING AND ANALYSIS METHODS


      The  sampling and  analysis methods used  in the  test  program
 are  individually  discussed below  along with  problems  encountered
 on site.

 Sampling

      The  first  task  was  to perform an  EPA Method  1  procedure  to
 ensure  the  extraction  of a representative sample.   The sampling
 locations were  numbered  1 to  30 as shown  in  Figure  7.  Locations
 31 through  36 were not tested because,  on opening the test  port,
 fly  ash was  found 2  inches deep,  18  inches inside the duct.   The
 nearest upstream  disturbance  was  five  equivalent duct diameters
 away, and the nearest  downstream  disturbance was two  diameters
 away.   By using six  sampling  locations at the  remaining  five
 ports,  the  conditions  for sampling by  Method 1 were fulfilled.

      Method  2  (EPA)  was  then  performed to determine stack gas
 velocity  and flow rate at the sampling sites.   Method 3  (EPA),
 using an  integrated  sampling  train,  was employed to obtain  a
 representative  stack gas sample which  was analyzed  in an Orsat
 analyzer.

     Method  4  (EPA)  was  initially  used to determine moisture
 content in the  stack gas.   The  measured moisture content of gas
 on January 26,  27, and 28  was both low and constant; therefore,
 Method  4  was not  performed on  subsequent  test  days  (January 31,
 February  1,  2,  3,  and  4).   However,  the back half of EPA Method
 5 was used to measure  the  moisture content of  the stack  gas on
 the latter days.   The moisture  content remained low enough and
 consistent enough  to insure that all of these  determinations
 were well within  isokinetic limits.

     To determine  particulate emissions,  EPA Method 5 was used.
 On January 26 and  27,  isokinetic results  were  not obtained due
 to the difficulty  of reading the inclined manometer at the very
 low stack velocities found.   Subsequent test runs utilized a
more precise manometer to  read  pressure drop.   The  level of the
precision manometer was  checked every  time the probe was moved
 to a new  sampling  port.  Although  this ameliorated  the difficul-
 ties somewhat, precise velocity pressure  readings were still
difficult to obtain.
                              24

-------
                                                      3.5'

O 0
© Q

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O O O
o o o
o o o
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V"*^ T



• '•' i •••'•"'•••••!
0 ©
(jo) (jj)
o o
0 0
0 O
© (35)
v.^' ^ ^_x
''&&•:!:?'.& &i::::"rj ~'.



®_. _
o
o
o
<$
>«— X j
'i^'-.r..**" j-i*. '.]
                                                               6.75"
                                                               -^-
                                                            13.25^'
                                                             1
                                                                Ports
80* x 42  Inside Dimensions  of the
Breeching
                        Section A-A
Flyosh
          Figure 7.   Section of the  Sampling Location
                                25

-------
      As  soon as  the  Method  5  probe  cleared  the  second  sampling
 port,  then  EPA Method  6  samples  for sulfur  dioxide  were  taken
 with  the probe extending halfway into  the stack from the second
 sampling port (third actual port from  the bottom of the  duct).
 At  the conclusion  of the sulfur  dioxide  sampling, four samples
 were  taken  according to  EPA Method  7 for determination of oxides
 of  nitrogen.

      After  the oxides  of nitrogen samples were  taken,  a  HCN
 sample was  taken.  A sampling train similar to  that used in
 Method 6 was  employed, but  the midget  impingers  contained 0.05 N
 KOH instead of the absorbents used  in  Method 6.   The entire
 train consisted  of midget impingers.   The probe was inserted in
 the second  sampling  port with its tip  at the center line of the
 duct.

 Analysis

      Particulate samples from the EPA  Method 5  strains were
 assayed  by  the analytical precedures specified  in Method 5.
 However,  glass fragments were observed in residues  of  the probe
 rinses from some samples.   In order to correct  for  this  con-
 tamination,  observed glass  fragments were physically separated
 from  the residues, rinsed with acetone,  and allowed to dry before
 weighing.   The weights of the glass fragments were  subtracted
 from  the corresponding probe-rinse  residue  weights.

      Following gravimetric  assays of the Method  5 filter catches
 for particulate  weights,  each filter was extracted  with  three
 50-ml  portions of  cyclohexane.   The cyclohexane  was added to the
 filter in a  250-ml beaker,  the beaker  placed in  an  ultrasonic
 bath  for 20 min, and then the extract  decanted  into a  vial.  All
 extracts  from  runs with  the sample  fuel mixture  were composited.
 Hence, three composited  extracts were  obtained,  which  represent
 the coal-only  runs,  the  1 wood/1  coal  runs,  and  the 2  wood/1 coal
 runs.   These composited  extracts were  concentrated  to  5.0 ml with
 a gentle  stream  of dry nitrogen.  The  extracts were assayed for
 four POMs by gas chromatography  with electron capture  detection.
The chromatographic  column, 3% Dexsil  300 GC on  100/120  mesh,
was operated isothermally at  290°C  with a nitrogen  carrier flow
of  30 ml/min.  Injector  and detector temperatures were maintained
at  245 and 248°C, respectively.  A  mixed POM standard  containing
7,12-dimethylbenz[a]anthracene,  benz[a]pyrene,  3-methylchol-
anthrene, and dibenz[a,h]anthracene was utilized.

     Samples were prepared  for cyanide assay by  distillation ac-
cording  to standard  procedures and  were assayed  with a cyanide
ionspecific electrode.

     Samples were assayed for NOX by procedures  described in
EPA Method 7.
                               26

-------
     Samples were assayed for S02 by procedures described in EPA
Method 6.

     Aliquots of coal, wood chips, and 1:1 and 2:1 mixtures of
wood chips and coal were submitted to Industrial Testing Labora-
tories, Kansas City, Missouri, for proximate and ultimate
analyses.
                               27

-------
                    RESULTS AND  DISCUSSION
     The results of the test program  are presented  in Tables  5
and  6.  Table  5 displays the measured or uncorrected values while
Table  6 displays results corrected  for anisokinetic test condi-
tions  and low-flue gas velocities.  These corrections are
discussed next.

Discussion of  Test Results

     Natural draft-flue gas circuits  are inherently unable to
overcome large resistances to gas flow.  As a consequence, gas
velocities must be kept very low in order to minimize the
pressure drop  due to skin friction.   The flue gas velocity in
the  breeching  at Rolla was only about 500 ft/min which
corresponds to a velocity pressure of = 0.01 in of water.  These
low  values as well as the turbulent,  fluctuating nature of low
in real systems, make the manometer readings unreliable.

     In order  to overcome these difficulties, the flue gas flow-
rate was calculated for each test from the Orsat analysis of  the
specific fuel mixture used for the test.  It is necessary to  use
the Orsat analysis of the sampling location because the flue  gas
composition is not constant throughout the system due to in-
leakage of ambient air.  Table 7 compares measured and calculated
flue gas flow-rates at the sampling location.

     The calculated flue gas flow-rates were used as the basis
for correcting the measured pollutants. . Because it is not
necessary to sample gaseous pollutants isokinetically, the
measured gaseous concentrations are unaffected by errors in flue
gas flow-measurement;  however, in calculating the total weight
rate of pollutant from the concentration, the corrected flue
gas flow-rate does make a difference.

     The measured particulate concentration was corrected for
anisokinetic samplings by using a technique suggested by Badzioch
(11).  His method is summarized by Equation 2.
            |J + (1 - a)]  1
c = Cs iLL + (1 - a)     where:                           (2)
     C  = true fly ash concentration

     Cs = sampled fly ash concentration

                               28

-------
            TABLE  5.  TEST  RESULTS  (UNCORRECTED)
Coal only

Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam


so2
lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(measured)
measured/
expected
Ib/lb steam

NO
	 x
lb/106 Btu
ppm
Ib/hr
Ib/lb steam

HCN*(yg/ft3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
acetaldehyde
(ppm)

1/28/77
0.1776
0.0312
2.21
3.09 x
, A-4
10

2.26
340

81.7

28.11

0.34
3.9 x
io-3


0.19
40.85
2.43
3.4 x
io-4
_
1.3



0.15

0.6
1.3


0.5
Run No. 1
2/2/77
0.371
0.0463
3.04
5.28 x
—4
10

2.7
289

53.8

22.21

0.41
3.8 x
io-3


0.28
41.6
2.29
4.0 x
io-4
M
1.7



0.2

0.6
1.5


trace
Run No. 2
2/2/77
0.159
0.0207
1.31
2.27 x
in'*
10

2.03
225

53.8

16.65

0.31
2.9 x
io-3


0.20
31.5
1.67
2.9 x
io-4
M
1.4



0.1

0.9
0.8


* "

Avg
0.236
0.033
2.19
3.55 x
— 4
10

2.33
285

63.1

22.32

0.35
3.5 x
ID'3


0.22
38
2.13
3.4 x
io-4
_
1.5



0.15

0.7
1.2


<0.5
* Below detection limits
                               29

-------
                       TABLE 5 (continued)
                                         Coal only
 Ethanol,
   butanes,  and
   butenes(ppm)
 Total  HC  (ppm)
 7,12-dimethyl-
   benz[a]
   anthracene*
   (ng/scf)

 benz[a]pyrene*
   (ng/scf)
 3-methylcho-
   lanthrene*
   (ng/scf)
 dibenz[a,h]*
 anthracene
   (ng/scf)

 Boiler
                     1/28/77
0.2
4.05
Run No. 1

2/2/77
trace
=4
Run No. 2

2/2/77
                                     Avg
             <0.2
             =4.25
                                      <5


                                      <7


                                      <37
Ib coal/hr
Ib wood/hr
Ib steam/hr
106 Btu/hr in
% excess air
Steam enthalpy
(Btu/hr)/
Fuel heat in
(Btu/hr)
flue gas flow
(dscfm)
flue gas flow
(acfm)
1,083
0
7,154
12.45
40



0.69

8,266

13,722
713
0
5,757
8.2
133



0.84

7,660

11,989
713
0
5,757
8.2
139



0.84

7,402

11,484
836
0
6,223
9.6
104



0.79

7,776

12,398
* Below detection limits
                               30

-------
                    TABLE 5  (continued)


Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam

so2
lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(measured)
measured/
expected
Ib/lb steam

NO
X
lb/106 Btu
ppm
Ib/hr
Ib/lb steam

HCN*(yg/ft3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
acetaldehyde
(ppm)
1:1
Run No. 1
2/1/77
0.460
0.0776
5.56
6.70 x
io-4

1.57
263

65.9

19

0.29
2.3 x
io-3


0.39
77.9
4.69
5.6 x
io"1
«.
2.5



trace

0.4
2.2


1.0
wood to coal
Run No. 2
2/1/77
0.303
0.05736
3.67
4.42 x
io-4

1.49
262

65.9

18.10

0.27
2.2 x
ID'3


0.28
62.8
3.37
4.1 x
io-4
_
1.8



0.5

0.7
1.8


0.1
volume ratio

2/4/77
0.363
0.0606
4.14
6.42 x
ID'4

2.35
334

61.6

26.88

0.44
4.2 x
io-3


0.19
37.8
2.17
3.4 x
io-4
—
1.5



0.3

0.9
2.8


trace


Avg
0.375
0.065
4.46
5.85 x
io-4

1.80
286

64.5

21.32

0.33
2.9 x
ID'3


0.29
59.5
3.41
4.4 x
10-"
—
1.9



<0.4

0.7
2.3


<0.6
* Below detection limits
                               31

-------
                       TABLE 5 (continued)
Ethanol,
  butanes, and
  butenes(ppm)
Total HC  (ppm)
7,12-dimethyl-
  benz[a]
  anthracene*
  (ng/scf)
                            1:1 wood to coal volume ratio
Run No. 1

2/1/77
0.3
=6.4
Run No. 2

2/1/77
0.2
5.1
                                             2/4/77
                                             = 5.5
                                                        Avg
<0.3
= 6.2
benz[ a] pyrene*
(ng/scf)
3-methylcho-
lanthrene*
(ng/scf)
dibenz[a,h]*
anthracene
(ng/scf)
Boiler
Ib coal/hr
Ib wood/hr
Ib steam/hr
10 6 Btu/hr in
% excess air
Steam enthalpy
(Btu/hr)/
Fuel heat in
(Btu/hr)
flue gas flow
(dscfm)
flue gas flow
(acfm)
-

863
326
8,303
12.1
156



0.82

8,365

14,218
-

863
326
8,303
12.1
180



0.82

7,463

12,426
-

806
326
6,438
11.4
125



0.68

7,977

12,921
<5
<7
<38

844
326
7,681
11.87
154



0.77

7,935

13,188
* Below detection limits
                               32

-------
                     TABLE  5  (continued)


Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam

S02
lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(measured)
measured/
expected
Ib/lb steam

NO
	 x
lb/106 Btu
ppm
Ib/hr
Ib/lb steam


HCN* (yg/f t3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
acetaldehyde
(ppm)


1/31/77
0.269
0.0443
3.50
4.11 x
io-4

2.19
310

61.6

28.56

0.46
3.3 x
1Q-3


0.24
47.9
3.17
3.7 x
— 4
10
_
6.0



5.4

1.6
1.8


0.3
2 : 1 wood to
Run No. 1
2/3/77
0.360
0.0478
3.49
5.31 x
io-4

3.29
373

46.6

31.93

0.68
4.9 x
io"3


0.35
56
3.44
5.2 x
•1-4
10
_
1.3



0.2

0.8
1.3


0.8
coal volume
Run No. 2
2/3/77
0.331
0.04865
3.21
4.81 x
ID'4

2.94
334

46.6

28.57

0.61
4.3 x
1Q-3


0.27
47.4
2.62
4.0 x
— 4
10
^
1.6



0.5

0.7
1.0


trace
ratio

Avg
0.32
0.0469
3.40
4.74 x
io-4

2.81
339

51.6

29.69

0.58
4.2 x
ID'3


0.29
50.4
3.08
4.3 x
lrt-4
10
_
3.0



2.0

1.0
1.4


<0.6
*Below detection limits
                               33

-------
                       TABLE 5 (continued)
 Ethanol,
   butanes,  and
   butenes(ppm)
 Total HC  (ppm)
 7,12-dimethyl-
   benz[a]
   anthracene*
   (ng/scf)

 benz[a]pyrene*
   (ng/scf)
 3-methylcho-
   lanthrene*
   (ng/scf)
 dibenz[a,h]*
 anthracene
   (ng/scf)

 Boiler

 Ib coal/hr
 Ib wood/hr
 Ib steam/hr
 106 Btu/hr in
 % excess air
 Steam enthalpy
   (Btu/hr)/
  Fuel heat in
   (Btu/hr)
 flue gas flow
   (dscfm)
 flue gas flow
   (acfm)
                     1/31/77
= 15.1
        2:1 wood to coal volume ratio

             Run No.  1   Run No.  2

             2/3/77      2/3/77      Avg
797
573
8,518
13
81
0.78

9,202

16,068
= 4.4
603
418
6,567
9.7
341
0.81

8,538

13,648
trace
= 3.8
603
418
6,567
9.7
181
0.81

7,690

12,231
trace
=8
                                     <4


                                     <7


                                     <35
 668
 470
 7,217
 10.8
 201
 0.80

 8,477

 13,982
* Below detection limits
                               34

-------
              TABLE  6.   TEST RESULTS (CORRECTED)
Coal only

Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam

S02
lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(corrected)
corrected/
expected
Ib/lb steam

NO
	 x
lb/106 Btu
ppm
Ib/hr
Ib/lb steam


HCN*(ug/ft3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
Acetaldehyde
(ppm)

1/28/77
0.204
0.0265
2.54
3.55 x
IO"4

3.05
340

81.7

38.03

0.47
5.3 x
10"3


0.26
40.85
3.29
4.60 x
m-4
10
_
1.3



0.15

0.6
1.3


0.5
Run No. 1
2/2/77
0.390
0.0438
3.20
5.56 x
io-4

3.11
289

53.8

25.48

0.47
4.4 x
io"3


0.32
41.6
2.63
4.57 x
~4
10
—
1.7



0.2

0.6
1.5


trace
Run No. 2
2/2/77
0.170
0.0194
1.39
2.41 x
ID'4

2.29
225

53.8

18.80

0.35
3.3 x
io"3


0.23
31.5
1.88
3.27 x
—4
10
mm
1.4

-

0.1

0.9
0.8


•*

Avg
0.255
0.0299
2.38
3.84 x
io-4

2.82
285

63.1

27.44

0.43
2.97 x
io"3


0.27
38
2.60
4.15 x
iA-4
10
—
1.5



0.15

0.7
1.2


<0.5
* Below detection limits
                               35

-------
                       TABLE 6 (continued)
                                         Coal only
Ethanol,
  butanes, and
  butenes(ppm)
Total HC  (ppm)
7,12-
  dimethylbenz
  [a]*, anthra-
  cene  (ng/scf)
benz[a]pyrene*
   (ng/scf)
3-methylcho-
  lanthrene*
   (ng/scf)
dibenz[a,h]*
  anthracene
   (ng/scf)

Boiler
1/28/77
Run No.
2/2/77
1
Run No.
2/2/77
2
Avg
0.2
4.05
trace
=4
<0.2
=4.25
                                     <5


                                     <7


                                     <37
Ib coal/hr
Ib wood/hr
Ib steam/hr
106 Btu/hr in
% excess air
Steam enthalpy
(Btu/hr)/
Fule heat in
(Btu/hr)
flue gas flow
(dscfm)
flue gas flow
(acfm)
1,083
0
7,154
12.45
40



0.69

11,186

18,569
713
0
5,757
8.2
133



0.84

8,546

13,756
713
0
5,757
8.2
139



0.84

8,358

12,967
836
0
6,223
9.6
104



0.79

9,363

15,097
* Below detection limits
                               36

-------
                      TABLE  6  (continued)


Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam


so2
lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(corrected)
corrected/
expected
Ib/lb steam

NO
x
lb/106 Btu
ppm
Ib/hr
Ib/lb steam

HCN*(yg/ft3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
Acetaldehyde
(ppm)

Run No.
2/1/77
0.519
0.0675
6.28
7.57 x
-4
10 *

2.04
263

65.9

24.67

0.37
2.97 x
io"3


0.50
77.9
6.09
7.33 x
10"4
mm
2.5



trace

0.4
2.2


1.0
1 : 1 wood to
1 Run No.
2/1/77
0.354
0.0478
4.28
5.15 x
-4
10 4

2.09
262

65.9

25.25

0.38
3.04 x
10~3


0.39
62.8
4.71
5.67 x
io"4
^
1.8



0.5

0.7
1.8


0.1
coal volume
2
2/4/77
0.411
0.0527
4.69
7.27 x
— 4
10

3.07
334

61.6

34.99

0.57
5.43 x
10~3


0.25
37.8
2.82
4.38 x
io"4
^m
1.5



0.3

0.9
2.8


trace
ratio

Avg
0.428
0.056
5.08
6.66 x
-4
10

2.4
286

64.5

28.30

0.44
3.81 x
10~3


0.38
59.5
4.54
5.79 x
ID'4
^
1.9



<0.4

0.7
2.3


<0.6
* Below detection limits
                               37

-------
                       TABLE 6 (continued)
                             1:1 wood to coal volume ratio
Ethanol,
  butanes, and
  butenes  (ppm)
Total HC  (ppm)
7,12-
  dimethylbenz
  [a]*, anthra-
  cene  (ng/scf)
benz[a]pyrene*
  (ng/scf)
3-methylcho-
  lanthrene*
  (ng/scf)
dibenz[a,h]*
  anthracene
  (ng/scf)

Boiler
Run No. 1

2/1/77
                      0.3
                      = 6.4
Run No. 2

2/1/77
            0.2
            5.1
                                              2/4/77
            = 5.5
                                                          Avg
0.3
=6.2
                                                           <5
                                                           <7
                                                           <38
Ib coal/hr
Ib wood/hr
Ib steam/hr
10 6 Btu/hr in
% excess air
Steam enthalpy
{ Btu/hr)/
Fuel heat in
(Btu/hr)
flue gas flow
(dscfm)
flue gas flow
(acfm)
863
326
8,303
12.1
156



0.82

10,863

18,464
863
326
8,303
12.1
180



0.82

10,442

17,386
806
326
6,438
11.4
125



0.68

10,383

16,818
844
326
7,681
11.87
154



0.77

10,563

17,548
* Below detection limits
                               38

-------
                     TABLE  6  (continued)


Particulate
lb/106 Btu
gr/dscf
Ib/hr
Ib/lb steam

lb/106 Btu
ppm
Ib/hr
(expected)
Ib/hr
(corrected)
corrected/
expected
Ib/lb steam

NO
	 x
lb/106 Btu
ppm
Ib/hr
Ib/lb steam

HCN*(yg/ft3)
Methane (ppm)
Acetylene,
ethylene,
and ethane
(ppm)
Formaldehyde
(ppm)
Propane (ppm)
Methanol and
Acetaldehyde
(ppml


1/31/77
0.260
0.0457
3.38
3.97 x
io-4
2.06
310

61.6

26.76

0.43
3.14 x
10~3


0.23
47.9
2.97
3.49 x
io"4
_
6.0



5.4

1.6
1.8


0.3
2:1 wood to coal
Run No. 1
2/3/77
0.341
0.0502
3.31
5.06 x
1C'4
2.96
343

46.6

28.79

0.62
4.38 x
10~3


0.32
56
3.10
4.72 x
ID'4
—
1.3



0.2

0.8
1.3


0.8
volume
Run No.
2/3/77
0.352
0.0455
3.41
5.11 x
ID'4
3.35
334

46.6

32.52

0.70
4.95 x
io"3


0.31
47.4
2.98
4.54 x
l
-------
                      TABLE  6  (continued)
Ethanol,
  butanes, and
  butenes  (ppm)
Total HC  (ppm)
7,12-
  dimethylbenz
   a *, anthra-
  cene  (ng/scf)
benz a pyrene*
   (ng/scf)
3-methylcho-
  lanthrene*
   (ng/scf)
dibenz a,h *
  anthracene
   (ng/scf)

Boiler

Ib coal/hr
Ib wood/hr
Ib steam/hr
106 Btu/hr in
% excess air
Steam enthalpy
  (Btu/hr)/
  Fuel heat in
                    1/31/77
        2;1 wood to coal volume ratio

             Run No. 1   Run No. 2

             2/3/77      2/3/77      Avg
= 15.1
797
573
8,518
13
81
= 4.4
603
418
6,567
9.7
341
trace
= 3.8
603
418
6,567
9.7
trace
=8
                                     <4


                                     <7


                                     <35
 668
 470
 7,217
 10.8
 201
(Btu/hr)
flue gas flow
(dscfm)
flue gas flow
(acfm)
0.78

8,624

15,058
0.81

7,698

12,305
0.81

8,753

13,921
0.80

8,358

13,761
* Below detection limits
                              40

-------
       TABLE  7.   COMPARISON OF MEASURED AND CALCULATED FLUE GAS FLOW RATES
Run No.
Date
Measured*
Calculated*


1/28
8,266
11,186
Coa^
No. 1
2/2
7,660
8,546

No. 2
2/2
7,402
8,358

No. 1
2/1
8,365
10,863
1:1
No. 2
2/1
7,463
10,442

2/4
7,977
10,383


1/31
9,202
8,624
2:1
No. 1
2/3
8,538
7,698

No. 2
2/3
7,690
8,753
* Flue gas flow rate - dscfm

-------
     V  = true duct velocity  at  sampling  location

     Vs = sampling velocity

     a  = parameter  (0.5  recommended  by Badzioch for  stoker-
             fired boilers)

     The correction of  the measured particulate concentration  is
predicted on the reasonable assumption that, on the average, the
ratio of true velocity  to sampling velocity at each point will
be equal to  the ratio of  corrected flue gas flow-rate to measured
flue gas flow-rate.  Therefore,  Equation  2 becomes:


     C = Cs[22| + (1 -  a)]'1  where:                          (3)


     C  = true fly ash  concentration

     Cs = sampled fly ash concentration

     Qc = corrected flue gas  flow rate

     Qs .= sampled flue  gas flow  rate

     a  = parameter  (as before)

     These values of particulate were plotted in Figure 8 versus
excess air.  A least square fit was drawn through the data and
the correlation was quite good.  A large part of the  change in
particulate  loading can be related to the large changes in excess
air.  This was especially true in the 1:1 ratio wood  to coal.
The particulate was also plotted versus weight ratio  of coal in
the fuel in  Figure 9.  A least square fit was constructed through
this data, and then to correct for excess air, the excess air
versus weight ratio was plotted.  These data were also fitted
with a first order,  least square fit.  Then by taking the excess
air change for the weight ratios of the data times the slope of
the particulate-versus-excess air curve, a correction was made
to the particulate-versus-weight ratio plot.

     The increase in particulate from all coal to 59%  coal was
approximately 14%, on the corrected curve a change from 0.2916
lb/106 Btu to 0.33 lb/106 Btu, respectively.

     No consistent increases or decreases were apparent in the
NOX,  S02,  or POMs when increasing amounts of wood chips are
substituted  for coal.  There does appear, however, to  be a
consistent increase in  total  hydrocarbon  (THC).

     It was expected that SC>2 would decrease substantially with
increasing amounts of wood fuel.  The absence of this  expected
trend coupled with the low ratios of measured SC>2 to  expected  S02
has cast doubt on the reliability of the S02 results.  It was
initially thought that perhaps the S02 concentration  was non-
uniform across the breeching at the sampling location  due to


                               42

-------
 £ 0.4

-------
UJ
o
X
UJ
190


170


150


130


 110


 90


 70


 50


 30
  oo
 £
  O
  ^
   *
  .0
  _l


-0.4
   -0,3
   -0.2
   - 0.1
    0.0
            ILb./IO6 Btu = 4.30xlO"4 Kg/MJ

                         O
         A PARTICULATE
                           (% WEIGHT vs

                               PARTICULATE O)
               (CORRECTED  CURVE)
         (% WEIGHT vs EXCESS AIR  D)
             n
                     I	I
      50
               60       70      80      90

                WEIGHT PERCENT  COAL
I	|	I
                                              100
Figure 9.  Particulate Correction as a Function of Weight
            Percent Coal
                        44

-------
stratified in-leakage of ambient air.  However, a check of the
temperature profile and Reynolds number in the breeching at the
sampling location indicates that mixing did take place as
demonstrated in calculations of these profiles and Reynolds
Numbers (12).

     An additional basis for comparison of particulate and SC>2
results is provided by a compliance test performed on the boiler
in 1974 while firing coal only.  Table 8 gives the average of
this compliance test compared to the average of the coal-only
results from this test program.  As can be seen from Table 8,
there is agreement on the particulate results, but again, it
appears that the current SC>2 results are invalid.
  TABLE 8.  COMPARISON OF 1974 COMPLIANCE TEST WITH COAL-ONLY
            RESULTS OF CURRENT PROGRAM
       Test dates
1974
1977

Heat input (MBtu/hr)
Steam production (Ib/hr)
Particulate (Ib/MBtu)
Particulate (gr/scf)
SO (ppm)
SOX (Ib/hr)
Measured SOx/Expected SOX
Sulfur in coal (%)
Ash in coal (%)
16.95
12,310
0.29
0.065
744
65.4
1.05
2.14
11.17
9.6
6,223
0.255
0.0299
285
27.44
0.43
3.17
11.53
     Particle size determination was  attempted  with impactors
during each test; however,  the  results were  invalidated by  the
build-up of a static electricity charge  on the  collected sample.
This charge build-up prohibited accurate weighing  of the small
amount of particulate collected (in fact, negative weight gains
were detected on  some stages).
                                45

-------
           FUEL TESTING  (UNIVERSITY OF MISSOURI-ROLLA)


     Further  testing of  the  fuel was undertaken during  the months
of June, July, and August of 1977  to better define  the  SC>2
concentrations and nitrogen  oxides and particulate  effluents.
In order to try to avoid the problems of dilution of effluents
with air leakage into the breeching, all the measurements were
taken at the  top of the  boiler.  The sampling  location  was the
section of breeching connecting No. 2 boiler to the main
breeching serving all three  boilers; see Figure 6.

     Basically three different blends were again fired; 2:1, 1:1,
and all coal, for three  different  coals; see Table  2.   An attempt
was made to duplicate the steam flows and flue gas  temperatures
for each run.  A steam load  of approximately 6000 Ib/hr (2733
Kg/hr) was the normal goal.   To accomplish this goal, manual
control was normally used as with  the previous test except for
the occasional automatic mode when running with all coal.

     During each run, three  categories of data were taken.
First, a performance comparison of the blended fuels was made
using the boiler charts  and  integrators, and periodic Orsat
analyses (every 30 minutes).  Second, emissions of  sulfur
dioxide, nitrogen oxides, and particulate matter were found by
continuous monitoring of the  flue gases.  Finally, daily tests
were conducted to determine  heating values of the fuels and
refuse  (bomb  calorimeter), sulfur contents of the fuels and
refuse  (titration), and  fuel  moisture contents.

     The basic system employed to determine the gaseous
pollutants in the flue gas involved an electrochemical gas monitor
that provided sulfur dioxide  and nitrogen oxides concentrations
in parts per million on  a continuous basis.  Upstream, removal
of particulate matter was accomplished by a paper filter thimble,
and the water vapor removed  by an ice bath condenser.  Calibra-
tion of the instrument using  standard sulfur dioxide and nitric
oxide calibration of the instrument was performed at least once
daily using standard sulfur  dioxide and nitric oxide calibration
gases.   Periodic sampling per EPA Method 6 was performed to veri-
fy the accuracy of the instrumentation.

     Particulate data was obtained in the form of opacity with
a stack-mounted transmissometer.   The transmissometer was a
fully automated system using a modulated light beam with 3%
accuracy.   The unit provided a zero and span calibration to the

                              46

-------
system automatically every hour.   The output was read and
recorded every 30 minutes.
                               47

-------
                            ANALYSIS
     The  analytical  technique  used  to  reduce  the data  was
 basically a  combustion  analysis  described  in  many tests  on the
 subject  (12-15),  including  a heat balance  of  each run  made.
 Modifications  to  the analysis  included a totally dry basis con-
 sideration and the use  of both carbon  dioxide and oxygen Orsat
 results to determine excess air.  The  dry  basis  analysis is
 desirable, since  both the gas  monitor  and  the Orsat apparatus
 operate essentially  on  the  dry basis.

     First/  the net  composition  of  the fuel is determined  from
 the volumetric ratio of the wood to the coal  and the respective
 ultimate  analyses and moisture contents.   By  weighing  several
 samples,  it  was determined  that  for the coal  and wood  sizing
 and moisture contents experienced,  a mixture  of  50% coal/50%
 wood by volume corresponds to  72% coal/28% wood  by weight.
 Accordingly, weight  fractions  for other blends may be  calculated,
 given the volumetric ratio and considering any coal added  along
 the sides of the  blended fuel, by the  relationship
WF  =
           72
              M
                    + M
              M
                                                              (4)
where WFC is the weight fraction of coal in the mixture burned,
Mp is the weight of the blended fuel, Mc is the weight of any
additional coal that may be added along 'the sides, and G is  the
volumetric ratio of wood to coal.

     To calculate the effective composition of the fuel fired,
the following expression is used for all components except
oxygen and hydrogen:
Z = Z WF (1-MC )  +
     C^  *•*     v
                   Z (1-WF ) (1-MC )
                    Vr     t^      Wr
                                                              (5)
where Z, Zc, Zw are the weight percentages of a component of the
net fuel, coal, and wood respectively, MCC is the moisture
content of the coal, and MCw is the moisture content of the wood.
For the oxygen and hydrogen contents,
                              48

-------
     02 = [QC(1-MCC)  + S^L MCc]WFc + [Ow(l-MCw)  -f	

           (l-WFc)                                           (5a)
     H2 = EHC(1-MCC)  + ^ MCc]WFc + CHW(1-MCW)  + ^ MCw]

           (1-WP )                                           (5b)


The symbols are the same as in the previous case with 02
representing the weight percentage of oxygen and H2 representing
the weight percentage of hydrogen.

     The refuse contained often times considerable unburned
carbon and sulfur.   To account for this correction, the carbon
and sulfur weight percentages were modified by
     CAB - c - l=y A


     SAB = A - I=fr A                                       <6b)

     In these expressions, CAB and SAB denote the weight
percentages (pound constituent per 100 pounds fuel) actually
burned, while C, S, and A are the weight percentages of carbon,
sulfur, and ash respectively in the composite fuel.  As
calculated previously, 6 symbolizes the weight fraction of carbon
in the refuse, and y symbolizes the weight fraction of sulfur
in the refuse.

     Next, the theoretical amount of oxygen required per 100
pounds of fuel is found by a molar balance and the ideal gas law.
           ¥  <         -    +

where VTO is the volume of theoretical oxygen required per  100
pounds of fuel, R is the ideal gas constant  (1,545  Ibf-ft/lb-
mole-°F) , T is the absolute temperature  in degrees  Rankine,  and
P is the pressure, in pounds per  square  foot.  The  corresponding
volume of nitrogen accompanying the oxygen  (per  100 pounds  of
fuel) is given by VTN/ where


     VTN = IT VTO                                             (8)

     The theoretical volume of dry combustion products  plus the
volume of nitrogen from the fuel  plus  the volume of nitrogen
from the combustion air is then equal  to the theoretical dry


                               49

-------
flue gas volume per 100 pounds of fuel, or


     ..   _ RT ,CAB ,  SAB   N2. .  ..
     V   -    {    + ~32 +   > + V
      CT         2     32    2      TN

     Here, Vc«r represents the  theoretical  dry  flue  gas volume
per 100 pounds of fuel, and N2 represents  the  pounds  of nitrogen
per 100 pounds of fuel.

     The actual volume of dry  flue gas  per 100 pounds of fuel
can be written as V    , where

     V    = v   + V                                          (10)
      ACT   VCT    EA                                        UU'

     Here, Vg, is the volume of excess  air introduced into  the
system per lufj pounds of fuel.  VCT is  calculated assuming
stoichiometric fuel mixtures, but VEA maY  ^e calculated from
the Orsat analysis of the flue gas.  The amount of  excess air
in this boiler is considerable, often over 120%, and  consequently
the amount of carbon monoxide present is extremely  small, and
may be neglected.  Determination of VEA was done considering
both the carbon dioxide and oxygen percentages, and results
averaged.  The following formulas were  used.


             RT  ,CAB   SAB>
              P    19    "39'
     a po  = - _  _                                    c\ i =1 ^
       ^U2   ^v   T^J                                       U-l-a)
         ^    VCT    EA|
                        U2
                             CO,
            21
     % °2 = V - + V  |                                       (12a)
        ^   VCT + VEA|
                       2

              V  (% 0 )

     VEA    =  2>% 0                                       <12b>
    VEA
                              50

-------
     Here, % CC>2 and % 62 are the volumetric percentages of
carbon dioxide and oxygen respectively from the Orsat analysis
of the flue gas.  VEA|CO  and VEA|O  represent the volume of

excess air present per 100 pounds of fuel from carbon dioxide
and oxygen analyses respectively.  Note that the weight
percentage of sulfur actually burned appears in Equations (lla)
and (lib).  The reason for this is that the Orsat apparatus
absorbs both carbon dioxide and sulfur dioxide during the carbon
dioxide measurement.

     It was found in this research that the combined results of
a carbon balance and an oxygen balance tended to average but
errors made in reading the Orsat, and gave satisfactory results.

     Now that the volume of dry flue gas per 100 pounds of fuel
has been calculated, the fuel rate in pounds per hour may be
used to calculate the volumetric flow rate of the dry flue gas.
When the pressure and temperature are taken as instrument
conditions, the volumetric flow rate may be combined with the
concentration of the pollutants and the ideal gas law to yield
the mass flow rate of the pollutant.

     The heating rate may be computed by considering the dry,
higher heating values of the coal and wood, the fueling rate,
and the moisture contents and weight fractions.

     HR = FR [HHV  (1-MC )WF  + HHV  (1-MC )(1-WF )]           (14)
                 c     c   c      w     w      c

where HR denotes the heating rate in unit energy input per unit
time, HHVC and HHVW represent the dry higher heating values of
the coal and wood respectively.  Fueling rate  (FR) is unit
weight of fuel per unit time.
                               51

-------
                    RESULTS AND DISCUSSION
     The results for gaseous and particulate emissions are
graphically presented in Figures 10, 12, and 13.

     Sulfur dioxide emissions, as plotted in Figure 10, show a
consistent decrease in the pounds per million Btu emissions
index as the percentage of wood, increases in the fired fuel.
The solid lines indicate the results of the experimental data
while the dashed lines represent the expected data based on the
sulfur actually burned.  Sulfur accountability was rather
encouraging, deviating about 17% at the most from the ideal or
expected value.  The curve in Figure 11 was an attempt to
normalize the data.  Each point was divided by an all coal value
for that set of coal runs and the expected curve was the
normalized expected curve for the 3.12% sulfur coal.  This was
identified as coal No. 2 in Table 2.

     The nitrogen oxides data, presented in Figure 2, were
scattered as expected, since formation of nitrogen oxides is
basically a function of flame temperatures, residence time, and
percent excess air, the first two of which are unaccounted for
variables in this testing program.  Due to this uncertainty,
no relationship between nitrogen oxides emissions and the wood
content of the fired fuel could be determined.  The emissions
were also considered versus percent excess air, and moisture
content, with no success.  A complete study of the nitrogen
oxides emissions would require additional experimental con-
siderations not included in this work.

     The particulate emissions, considered as opacity, are
plotted versus excess air in Figure 13.  The presentation of the
data in this manner presents an almost linear relationship
between opacity and excess air.  The linear relationship to
excess air was the same as that demonstrated by the particulate
data taken by Midwest Research Institute.  Again the opacity
versus weight percent was plotted in Figure 14 for all three
fuels.   This data was fitted with least square linear approxima-
tion as plotted.   In order to investigate the effect of the
excess air,  the opacity versus weight was plotted in Figure 15
for 2.44% sulfur coal.  Again, the change in the excess air
from the linear curve was found to be 63% in going from 59%
coal to all coal on the curve.  Multiplying this change in
excess air by the slope of the opacity versus excess air curve
CO.211)  produces a Aopacity due to excess air of 1.33.

                              52

-------
U1
     m  5
    *0
          O 2.44%    A 3.12%    X 1.91%   A 3.29%


               I Lb/Btu = 4.30 xlO"4Kg/J
     ! 5t
     o>    P
                               A
     o
     Q_
   *
Q 3

X
O

0 2


-------
      1.2
      1.0
 •o
 0)
 LU


 "o
 o
 o
 cf
 CO
 0>
 (O
 o
 0)
 CM
     0.8
     0.6
     0.4
    0.2
                               A  O
                                           n
                          o
              n
O-2.44 % SULFUR  COAL



D-l.91%



A -3.12%
             D
                 10
       20
30
40
50
                WEIGHT  PERCENT  WOOD
Figure  11.  Normalized  Sulfur Dioxide  Output as a Function of

             Wood Percent
                           54

-------
Ul
Ul
      0>
      Q-0.8
   0.6
 «*
CO
UJ
Q0.4
X
o
     o
     o

     So
         	1	1             I
          O 2.44 %    A 3.21%     X 1.91%

              I Lb/Btu = 4.30 x IO"4 Kg/J
                                          A
         O


     A   X
          X
                  1
I
I
                                                     A 3.29%
                 10          20          30
                    WEIGHT  PERCENT WOOD
                                                             O  X
                        40
                       50
                Figure 12.  Nitrogen Oxides Emissions as a Function of
                            Fuel Blend

-------
     10-
Ul
a\
   0  ft
   2  8
   o
   UJ

   £6
   UJ
   Q_
       50
              i      i      i      i

             O  2.44%    A 3.21%
                     X 1.91 %
                      3.29%
                       O
                                                            1.91%
                                          O ,
 70


VOLUME
90
110
130
150
                             PERCENT  EXCESS  AIR
               Figure 13.  Opacity of Flue Gas as a Function of Excess Air
                           and Coal Sulfur Content

-------
  9.0
  8.0
  7.0-
  6.0
>•
a  5.0
 4.0
  3.0
          A
     50
             D
             D
                       A
                             I.9I%SULFURA)
                           3.12% SULFURO)
                          O
                           ;2.44%SULFURQ)
                         D
                         D
60      70
                                         90     K>0
            WEIGHT PERCENT COAL
Figure 14.
            Opacity as a Function of the Weight Percent of
              the Coal
                         57

-------
 Subtracting  this  from  the  curve  in Figure  15  produced  a  constant
 opacity  for  the weight variation in  coal from 59%  to 100%.
 Suggesting no change in  the particulate loading over the weight
 percent  range, it was  assumed the other two fuels  would  have
 similar  behavior.  This  behavior was also  suggested by the MRI
 data.  To link the Midwest Research  results to the results of
 the  summer testing program, tests of the River King coal was
 made.  The opacity readings, the SC>2, NOX  levels were  taken for
 this coal.   The run produced an  average opacity of 7.1 at an
 excess air value  of 88%.   With this  value  of  excess air, the
 particulate  value was  found from Figure 8.  The value  was
 0.282 lb/106 Btu.  The SO2 value for the run  was 4.7 lb/106
 Btu  accounting for 98% of  the expected amount and  the  NOX was
 2.2  lb/106 Btu.

     To  define the boiler  performance operation on the different
 coals and blends  boiler  heat balance data  was measured and
 presented.   The experimental results for the  various losses
 considered were plotted  as percent loss versus the weight
 percentage of wood in  the  fuel fired.  The results achieved
 were essentially  as expected, in view of the  natures of  the coal
 and wood.  It must be  remembered, however, that presentation of
 the  results  as percentages might prove deceptive since the net
 heating  value of  the fuels change with the wood and moisture
 content  of the composite fuels.

     Figure  16 depicts the decrease  in both dry gas loss and loss
 to unburned  combustible  as wood  content increases.  These are
 logical  results,  since the weight of both  combustion products
 and refuse per pound of  fuel decrease with increasing  wood
 content.

     Presented in Figure 17 are  the  various moisture losses.  As
 expected, the most severe  dependence on wood  content appeared
 in the fuel moisture losses, and the least dependence  in the
 air moisture losses.

     The net efficiencies  (excluding what  are  normally denoted
 as radiation and  unaccountable losses)  appear  in Figure  18.  It
 is interesting to notice the slight  increase  in efficiency as
 the wood content  in the fuel increases.  However,  in terms of
 steam generation, the  decrease in the net  heating  value  resulting
 from additional wood in the fired fuel offsets any increase in
efficiency.

     This fact is pointed  out in  Figure 19, where  the performance
 factor,  defined as pounds  of steam per pound  of fuel is  plotted
versus the weight percentage of wood in the fuel.  A slight
decrease with increasing wood content is evident,  as expected.
However,  considering the fact that the cost of coal is two to
three times the cost of wood waste,  the results are rather
encouraging.

                              58

-------
 QC

 5
 CO
 CO
 UJ
 O
/70

f50

130


I/O


 90


 70


 50


 30

 10
- 6
- 5
 o

 I
- 4
-  3
         2.44%  SULFUR  COAL
              n
        (%COAL vs OPACITY D)
                                    AOPAC/TY
(opacity corrected)      I
            a
                      (% COAL vs EXCESS

                              A/R A)

                      A
       50
            60
70
80
90
fOO
               WEIGHT PERCENT COAL
   Figure 15.  Opacity Correction Curve Function of the Weight
               Percent Coal
                          59

-------
      25

-------
            FUEL  HYDR06E
              AIR MOISTURE
LU
O
o:
UJ
a.
FUEL  MOISTUR
             0 COAL I   A COAL 2  X COAL3

                  1	
                  10
                20
30
40
50
                     WEIGHT  PERCENT WOOD
          Figure 17.
       Moisture Losses Due to Fuel Hydrogen, Air Moisture,
        and Fuel Moisture as a Function of Fuel Blend

-------
 0 COAL I   A COAL  2  X  COAL 3
       10           20          30

     WEIGHT  PERCENT  WOOD
Figure 18.  Net Efficiency Excluding Radiation and Unaccounted
            Losses as a Function of Fuel Blend

-------
o\
u>
     o:
     o
        12
        10
        8
     tu  6
     o
     o:
     O
8
          —   O COAL I   A COAL 2  X COAL 3
                                  i
  1
                     10          20          30

                         WEIGHT   PERCENT  WOOD
                   X
                  A
              40
50
                Figure 19.   Performance Factor (Pound Steam per Pound Fuel)

                            as a Function of Fuel Blend

-------
      As  to  the experience of actually burning the blended fuels,
 it  was concluded that while the existing automatic control
 system worked  relatively well for pure coal,  some modifications
 would be necessary for the firing of a blended fuel containing
 more  than 50%  wood by volume.   The firing of  blended fuels
 containing,  for instance,  67% wood by volume  requires significant
 operator attention,  especially when the moisture content is  high
 and when load  changes are severe.   This is due mostly to increased
 restriction  of the primary air flow caused by the faster stoker
 speed and the  damp fuel.   This problem would  not be as severe
 with  a spreader stoker.

      In  fact,  during the summer test there was a period of one
 week  where the area  received nine inches of rain.   This was  in
 the middle of  the  testing and the wood stockpile was considerably
 depleted, making it  much more susceptable to  the moisture.

      The fuel  for  the next week was mixed and loaded during  the
 rainy spell, including mixing on the wet coal yard.   The fuel  was
 so  wet,  it dripped water and the wood was completely saturated.
 When  this wet  fuel was admitted to the boiler,  the boiler began
 cooling  rapidly.   Holes  appeared in the air pattern of the fuel
 bed and  the  only way the fire was maintained  was with dry
 kindling thrown on top of  the fuel bed.   The  result was a total
 loss  of  boiler load  and  the boiler was quickly switched back to
 coal.  Several days  were allowed for drying and then the fuel
 ran again.   A  similar situation occurred but  by closing the
 damper and increasing the  air until the boiler smoked (positive
 pressure) the  fuel burned.   Firing the wet fuel was a problem
 for several  weeks  following this occurrence.   It wouldn't have
 been  as  severe if  larger stockpiles of wood were maintained.
 The outer layer of wood  tends  to protect the  center of the pile
 from  absorption.   The lack of  ignition was quite a change from
 the earlier  rapid  ignition problems.   During  the entire testing
 program,  close attention was  given to any possibly slagging
 problems.  There were none.  Ash and fuel samples  were taken
 daily and the  decrease in  ash  was  noticed as  a  function of
 increased wood content.  The  combustible in the ash  was also
 noticed  to be  reduced with the addition  of the  wood.

     There are  a number  of potential sources  of error  present  in
 the experimental portion of  this work,  and the  methods  of calcula-
 tion are especially  sensitive  to  some.   The largest  single
 source of error probably resulted  from the actual  blending of
 the fuel, maintaining a  uniform  blend  during  fuel  handling,  and
 accounting for  that  blend  in computation.   The  wood  was  often
very moist and  tended to cling to  the  sides of  the fuel bunker,
 segregating the blend.  Attempts to  correct this were  frequently
made,  but variations  did occur.

     An unresolvable  source of error  appears  in the  absorption  of
sulfur dioxide  in  the filter,  stainless  steel  filter holder, and

                               64

-------
stainless steel tubing.   From information presented by Slowik
and Sansone (16) ,  and Byers and Davis (17) ,  errors due to the
stainless steel portions would be less than 1% while errors due
to the filter paper itself could conceivably be as much as 10%,
depending on the relative humidity of the flue gas.

     A further look at the efficiency of this unit was made by
calculating the cost of yearly operation.  It was assumed that
the unit (boiler No. 2)  would be run for one year at an average
load of 6000 Ib/hr  (2730 Kg/hr) of steam.  This steam production
is equivalent to the generation of 52,560,000 Ib  (23,914,800 Kg)
of steam for the year.  This boiler, referring to Figure 19,
assuming all coal operation produced 7.7 Ib of steam/lb of coal.
To generate 52,560,000 Ib of steam would require 6,826,000 Ib of
coal using the 7.7 Ib/lb index.  This was 3410 tons of coal.
At $37.53/ton delivered the total coal cost was $128,000.

     If the same boiler was run for the year at 6000 Ib/hr with
a blend of 1 wood to 1 coal, the steam required is still
52,560,000 Ib of steam.   The boiler production from Figure 19
was 7.5 Ib of steam/lb of fuel.  This production and load
required 7,008,000 Ib of fuel or 3504 tons of fuel.  The cost
to provide this fuel at $12.50/ton for the wood and $37.53/ton
for coal was $106,950.00.  This cost provided a savings of
$21,050 over all coal operations and would have saved 887 tons
of coal.

     The amount of fuel for 2:1 was 3576 tons, which was 1645
wood and 1931 coal.  The cost was $72,470.00 for coal and
$20,560.5 for wood, a total of $93,032.5 or a potential savings
of $35,000.60 and 1453 tons of coal.  The dollar savings for
this 6000 Ib/hr load was plotted in Figure 20 for different
wood weight ratios.

     The completion of the testing was an attempt to use bark.
A dump truck load of the bark was brought to tne power plant and
blended with the coal on a 1:1 basis.  There were immediate
problems.  The fuel segregated badly as it was elevated into the
plant.  The segregation was worse in the bunker and the boiler
fuel was constantly varying from all coal to almost all fines
to wood and coal.  It was difficult to pass the combustion air
through the blend and holes again appeared.  An attempt was made
to fire the boiler like it was fired with the wet fuel, but it
just wasn't successful.  The conclusion drawn is  that the bark
has to be hogged, but it would still contain excessively high
concentrations of fines.  The pelletizing of the  bark was
attempted and appears very promising, but wasn't  tested.  The
HHV density and ash of the pellets were measured,  and indicated
they could possibly be fired alone with no coal.  This
possibility is very encouraging.
                               65

-------
      120
  40|
to

<30|

o
o
C20|

CO
e>
z


colOl
UJ
 100
co 80
£T
<


O
O
060
o
o
CO

840

-I
UJ
       20
                   FUEL COST
               O 2x1 wood

                 I xl wood
                 10
                     20
30
40
50
                   WEIGHT  PERCENT WOOD
      Figure 20.  Economic Results from the Blended Fuel Use
                          66

-------
                          REFERENCES
 1.   Lowe,  R.A.,  "Energy  Recovery  from Waste",  2nd  Interim
     Report,  U.S.  Environmental  Protection  Agency,  (SE-360.ii),
     1973.

 2.   Even,  J.C.,  et.  al.,  "Evaluation of  the  Ames Solid Waste
     Recovery System,  Part I", Environmental  Protection Agency
     Technical Series,  EPA-60012-77-205,  Nov.  1977.

 3.   Massengale,  Robert,  "Sawdust,  Slab and Edging  Weights  from
     Mixed  Oak Logs  of the Missouri Ozarks",  the National Logger
     and Timber Processor, April 1971.

 4.   Amos,  J.A. and  Massengale,  R. , "The  Wood Residues of
     Missouri's Eastern Ozarks Region", Report to the Economic
     Development Administration, Oct. 1976.

 5.   "Timber  Resource of  Missouri Eastern Ozark Region", 1972,
     USDA,  Forest Service Resource Bulletin,  NC-19,  Printed 1974.

 6.   Biotherm Energy Systems, Publication of  American Wood  Fiber
     Institute, Winn.,  Mich.,  48896.

 7.   Hall,  H.H.,  et.  al.,  "Comparison of  Fossil and Wood Fuels",
     Environmental Protection Agency Technology Series, EPA-
     60012-76-056, March  1976.

 8.   Jones, S.G.  and Massengale, R., "Missouri Sawmill Improve-
     ment Program",  a Publication of the  Missouri Conservation
     Department,  March 1975.

 9.   Massengale,  R.,  "Missouri Forest Products Industries",
     Missouri Department  of Conservation, 1975.

10.   Environmental Assessment  of Waste to Energy Processes,
     "Stationary Source Testing  at Power Plant of University of
     Missouri at Rolla",  EPA Contract No. 68-02-2166, MRI Project
     No. 4290-L,  September 1977.

11.   Badzioch, S., "Correction  for an Isokinetic Sampling of
     Gas-Borne Dust  Particles",  Journal of the Institute of
     Fuel,  March 1960.
                               67

-------
12.  Fryling, C.R., ed.,  Combustion Engineering/ 2nd edition,
     Combustion Engr. Co., Riverside, Cambridge, Mass., 1966.

13.  Smith, M.C. and Stinson, K.W. , Fuels and Combustion, Firs.t
     Edition, McGraw-Hill, 1952.

14.  Potter, P.J., Power Plant Theory and Design, 2nd Edition,
     Ronald Press Co.,  1959.

15.  Anonymous, Steam,  38th Edition, Babcock and Wilcox, New
     York,  N.Y., 1972.

16.  Slowik, A.A. and Sansone, E.B., "Diffusion Losses of Sulfur
     Dioxide in Sampling Manifolds", Journal of Applied Pollution
     Control Association, Vol. 24, No.  3, March 1974, pp. 245-  •
     247.

17.  Byers, R.L. and Davis, J.W., "Sulfur Dioxide Absorption and
     Desorption on Various Filter Media", Journal of Applied
     Pollution Control  Association,  Vol.  20, No. 4,  April 1970,
     pp.  236-238.
                              68

-------
                          APPENDIX A

                     FACILITIES STATEMENT
     The Power Plant to be used in the investigation has four
boilers as listed below:

     No. 1  Babcock and Wilcox, Integral Furnace and
            Boiler, 1944; 18,000 Ib/hr at 150 psig
            saturated

     No. 2  Babcock and Wilcox, Integral Furnace and
            Boiler; 18,00 Ib/hr at 150 psig saturated

     No. 3  Union Iron Works, 1957
            35,000 Ib/hr at 150 psig 405°

     No. 4  Erie City Iron Works
            50,000 Ib/hr at 150 psig, 405°

     All the boilers have Laclede chain-grate stokers.  The
     power plant has two turbines as listed below:

     Worthington Turbine, 150 psig steam with a General
     Electric Generator, 500 kw at 36000 RPM

     Elliott Turbine Generator, 150 psig, steam 36000
     RPM, 1000 kw.

     The power plant's primary load is the heating and cooling
of the  facilities on the campus.  The turbines are not presently
being used.
                               69

-------
         APPENDIX B




DATA COLLECTED AND CALCULATED

Date

6/14
6/15
6/16
6/21
6/22
6/22
7/5
7/6
7/7
7/8
7/12
7/13
7/14
7/19
7/20
7/21
7/26
7/27
7/27
7/28

Blend by
Volume
Blend
Iw: Ic
Iwrlc
coal
2w:lc
c
2w:lc
Iw: Ic
Iw: Ic
2w:lc
coal
2w:lc
Iw: Ic
Iw: Ic
2w:lc
2w:lc
3w:2c
coal
coal
coal
coal

Firing
Rate
#/hr
886.7
758.5
831.25
1026.2
954.3
902.1
934.8
921.7
947.0
759.0
990.4
928
950
1162
1048
956
884
835
885
1019
TABLE
DATA
% Sulfur
Ash
% SA
0.72
0.5
1.5
1.43
0.53
1.72
.27
.98
1.08
1.04
1.43
.05
.058
.055
.055
.055
.05
.05
1.3
1.2
B-l
% Carbon
Ash
% CA
21
21
33
22
18.3
20.7
20.2
20.6
21.6
27.9
21
21
19.8
22.6
24.7
27.5
25.4
28
30
31

Weight
Coal Ib/lb
WF
c
0.72
0.72
1
.5967
1
0.5926
0.7565
.7473
.6027
1
.5694
0.72
0.72
.563
.563
.6316
1
1
1
1

Sulfur
in Coal
S
2.44
2.44
2.44
2.44
3.12
2.444
3.12
3.12
3.12
3.12
3.12

1.911
1.911
1.911
1.911
1.911
1.911
3.12
3.12
             70

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  TABLE B-2




DATA PLOTTED
Sulfur
2.44
2.44
2.44
2.44
2.44
3.12
3.12
3.12
3.12
3.12
3.12
3.12
1.91
1.91
1.91
1.91
1.91
3.29
Weight %
Coal
.72
.72
100
.5967
.5926
100
.7576
.7473
.6027
100
.5694
100
.563
.563
.6316
100
100
100
SO 2
lb/106Btu
3.985
3.29
2.84
2.54
3.06
5.05
4.94
3.58
4.51
3.99
3.18
3.9
1.49
2.07
2.6
3.03
2.5
4.54
%
Deviation
126
98.9
75.7
94.8
107
104
115.7
89.8
124.9
86
101
86
72
99.6
107
100
83
.100
NOX
lb/106Btu
.3843
.306
.442
.405
.091
.05
.166
.54
.25
.24
.68
1.3
.46
.43
.51
.138
.36
.37
      71

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  TABLE B-2




DATA PLOTTED
Coal
Sulfur
1.91
1.91
1.91
1.91
1.91
1.91
3.12
3.12
3.12
3.12
3.12
3.29
2.44
2.44
2.44
2.44
2.44
2.44
Opacity
9.4
7.3
7.8
8.2
8.1
8.2
7.4
7
6.7
6.6
7.6
7.1
6.4
4.5
4.6
4.25
6
6.5
Excess Air
95
77
104
112
116
147
113
123
108
106
153
129
88
58
76
106
122.5
135
Weight %
Coal
72
56.3
56.3
100
56.94
63.16
100
100
1
74.13
60.27
100
59.26
72
59.67
72
100
100
      72

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                          APPENDIX C
                      REPORT OF ANALYSIS
MATERIAL:
One (1) sample of coal identified as Coal Sample 12-30-2
TEST REQUESTED:
Analysis of coal and screen test
RESULTS OF TESTS:
       SIEVE SIZE    % RETAINED ON SIEVE    % PASSED SIEVE
          1 in
           .750 in
           .500 in
           .375 in
           .250 in
          # 4
          # 6
% Moisture
% Volatile Matter
% Fixed Carbon
% Ash

% Sulfur
Btu
Btu  (Moisture & Ash Free)
19.81
18.78
22.00
17.26
12.18
3.54
3.17








'ree)







AS RECEIVED
7.60
35.83
47.00
9.57
100.00
2.03
11,892

80.19
61.41
38.41
22.15
9.97
6.43
3.26
DRY BASIS
	
38.78
50.86
10.36
100.00
2.2
12,870
14,357
                               73

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                                   TECHNICAL REPORT DATA
                            (Please read Instructions on the reverse before completing)
 \. REPORT NO.
   EPA-600/7-80-103
                              2.
                                                            3. RECIPIENT'S ACCESSIOf*NO.
 4. TITLE ANDSUBTITLE
 Wood Waste  as  a Power Plant Fuel  in The Ozarks
             5. REPORT DATE
                 May 1980
                                                            6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
 V. J. Flanigan
                                                            8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
 Mechanical  Engineering Department
 University  of Missouri - Rolla
 Rolla, Missouri  65401
                                                            10. PROGRAM ELEMENT NO.
                  EHE 62UB
             11. CONTRACT/GRANT NO.

                R804270-010
 12. SPONSORING AGENCY NAME AND ADDRESS
                                                            13. TYPE OF REPORT AND PERIOD COVERED
 Industrial  Environmental Research  Laboratory
 Office of Research and Development
 U. S. Environmental Protection Agency
 Cincinnati.  Ohio  45268          	
             14. SPONSORING AGENCY CODE

                   EPA/600/12
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
      The report discusses the testing program conducted  on a chain-grate  stoker
 boiler with  a blended coal and wood  waste fuel.  The boiler was designed  to  produce
 18,000 Ib/hr (8,200 kg/hr) of saturated steam at 150 psig (103.4 N/cm2).   The
 objective  of the tests was to determine the difference,  if any, in the performance
 and the emissions of the boiler  co-firing wood and coal  as compared to firing  coal
 alone.  Four different coals with  different sulfur contents were fired with  the wood
 waste.  The  wood waste content was varied up to 2/3 by volume.

      Results indicate that particulate and nitrogen oxide emissions are not  substan-
 tially altered by using wood waste as supplemental fuel  with coal for the test
 conditions adopted in the program.   Sulfur dioxide emissions decreased with  increased
 proportions  of wood waste in the coal-wood mixture, whereas total hydrocarbon  concen-
 tration increased when wood waste  content was increased.   Cyanide concentrations were
 not substantially affected by substitution of wood waste for coal; particulate poly-
 cyclic organic emissions were below  the detectable limits for all fuels used in the
 tests.
 7.
                                KEY WORDS AND DOCUMENT ANALYSIS
                  DESCRIPTORS
                                              b.lDENTIFIERS/OPEN ENDED TERMS
                           c. cos AT I Field/Group
 Air Pollution
 Wood Wastes
 Environmental  Tests
 Boilers
 Wood-Fired Boiler
 SASS Train
 SAM-1A Analysis
 Multimedia Effluent
  Sampling
18. DISTRIBUTION STATEMENT
 Release to the  Public
19. SECURITY CLASS (ThisReport)
 Unclassified     	
21. NO. OP PAGES
      86
                                              20. SECURITY CLASS (This page)
                                               Unclassified	  	
                                                                         22. PRICE
EPA Form 2220-1 (9-73)
                                                                     . US GOVERNMENT MINTING OFFICt 1980-657-146/5680

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