SW16C
NEW CHEMICAL CONCEPTS FOR
UTILIZATION OF WASTE PLASTICS
               An Analytical Investigation

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    NEW CHEMICAL CONCEPTS FOR
    UTILIZATION OF WASTE PLASTICS
             This report (SW-l6c) was prepared for
          the Federal solid waste management program
       by M.E. BANKS, W.D. LUSK, and R.S. OTTINGER
        TRW Systems Group, Redondo Beach, California
             under Contract No. PH 86-68-206
            Environmental Protection
            Librai.v, n-^icn V
            1 Hurth BacJror Drive
            Chicago, Illinois  60606
           U.S. ENVIRONMENTAL PROTECTION AGENCY
                         1971
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.25
                      Stock Number 5502-0044

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ENVIRONMENTAL PROTECTION AGENCY
     An environmental protection publication
  in the solid waste management series (SW-16c)

     For sale by the Superintendent of Documents
U.S. Government Printing Office, Washington, D.C. 20402
                Price xxx

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                   FOREWORD
A MAJOR EMPHASIS of the Solid Waste Disposal Act, Title II of Public
Law 89-272, October 20, 1965, was directed toward the conservation of
natural resources through the recovery  and utilization of the potential
resources in solid wastes.  Plastic wastes are  a growing concern among the
variety of solid wastes produced in this  country. These materials are
difficult to dispose of and are expected to serve an even larger role in the
future.

  The Federal  solid waste management program has decided to  investigate
the   possibility  of reacting  waste  plastic  with  various  reagents  in  a
high-temperature, gas-phase  reactor  in order to  produce chemicals for
eventual commercial use. The first step in the overall study has involved the
computer  simulation  of  the  thermodynamics and kinetics of various
reaction systems. This has produced design parameters and economic data
for  various systems. This report represents the results of Contract No. PH
86-68-206, which was prepared by TRW Systems Group, Redondo Beach,
California. The Federal  solid waste management program was represented
by Dr. Daniel F. Bender during the implementation of the contract and the
preparation of the report.

                               -RICHARD D. VAUGHAN
                                Deputy Assistant Administrator
                                   for Solid Waste Management

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                           CONTENTS
1. INTRODUCTION AND SUMMARY	   1





2. TECHNICAL APPROACH   	   3





     Phase I    	   3





     Phase II   	   4





3. THERMODYNAMIC ANALYSES	   4





     TRW Chemical Analysis Program and Thermochemical Data Base	   5





     Equilibrium Product Distribution Analyses	,   7





        Thermal Decomposition Reaction Systems	   7





        Hydrogen Chloride Reaction Systems	   7





        Ammonia Reaction Systems	   7





        Water Reaction Systems	   8




        Air Reaction Systems	   8





        Chlorine Reaction Systems	   8





     Reaction Path Analyses	   9





        Thermal Decomposition Reaction Path Analysis	   9





        Air-Plastic Reaction Path Analysis	   9





        Chlorine Reaction Path Species Analysis	  10





4. KINETIC ANALYSES	10





     Thermal Decomposition Kinetic Analysis	11





        Polystyrene	11





        Polyethylene	12

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          Polyvinyl Chloride	12





          Thermal Decomposition Preliminary Reactor Designs	13





      Waste Plastics/Chlorine Kinetic Analysis	13





          Polystyrene  .	   13





          Polyethylene and Polyvinyl Chloride	14





      Waste Plastics/Steam Kinetic Analysis    	14





      Waste Plastics/Air Kinetic Analyses	15





5. PRELIMINARY DESIGN AND ECONOMIC ANALYSES	16




      Waste Plastic/Nitrogen Processes	     "




          Polystyrene/Nitrogen    ,	16





          Polyethylene/Nitrogen	    17




          Polyvinyl Chloride/Nitrogen	





          Mixed Waste Plastics/Nitrogen	18





      Waste Plastic/Air (Oxygen) Processes	    18





          Polystyrene/Air and Polyethylene/Air Systems	18





          Polyvinyl Chloride/Air  and Mixed Plastics/Air Systems	  .    19





      Waste Plastic/Water Processes   .  •	    1"





          Polystyrene/Water	    19





          Polyethylene/Water	    20




          Polyvinyl Chloride/Water	    20





          Mixed Plastics/Water	    20





6. CONCLUSIONS AND RECOMMENDATIONS	    20





7. REFERENCES    	    23
8. BIBLIOGRAPHY
                                                                                                      25
INDEX OF FIGURES





1. Generalized Technique for Chemical Process Development	    29





2. Technical-Economic Analysis for Plastic/Coreactant Chemical Processes	    30





3. Project Flow Diagram	    31

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  4. Thermal Decomposition: Major Products Analysis  •	.,...,...«.   32





  5. Hydrogen Chloride: Major Product Analysis	33





  6. Ammonia: Major Product Analysis	34





  7. Water: Major Product Analysis	35





  8. Air: Major Product Analysis	36





  9. Chlorine: Major Product Analysis	37





10. Feasible Reaction Path Species, Thermal Decomposition, 773 K, 1 atm	38





11. Feasible Reaction Path Species, Air,  773 K, 1 atm, 70 Percent Plastic Material	39





12, Feasible Reaction Path Species, Chlorine, 773 K,  1 atm, 70 Percent Plastic Material  ......   40





13. Styrene Produced versus Solid Residence Time	41





14. Styrene Produced versus Solid Residence Time	   42





15. Styrene Produced versus Solid Residence Time	43





16. Nitrogen  Necessary per Gram of Styrene	44





17. Amount of Product versus Solid Residence Time	45





18. Amount of Product versus Solid Residence Time	   46





19. Amount of Product versus Solid Residence Time	   .   47





20. Nitrogen  Necessary per Gram of Product	48





21. HC1 Produced versus Solid Residence Time	49





22. HC1 Produced versus Solid Residence Time	50





23. Organic Product Formed versus Solid Residence Time	51





24. Organic Product Formed versus Solid Residence Time	52




25. HC1 and Organic Product Comparison at 723 K	   .   53





26. Semicontinuous Waste Plastics Reactor    	54





27, Decomposition and Chlorination Reactor System	   55




28. Amount of Products versus Residence Time	56





29. Grams of Trichloro Derivative Produced versus Residence Time	57





30. Semicontinuous Waste Plastics Reactor	58





31. Steam Consumption versus Residence Time for the Plastic Mixture	59





32. Steam Consumption versus Residence Time for the Plastic Mixture	60

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33. Waste Plastic Combustion Reactor	61

34. Proposed Process for the Decomposition of Polystyrene with Nitrogen as a Heat Carrier  ....  62

35. Proposed Process for the Decomposition of Polyethylene with Nitrogen as a Heat Carrier  ....  63

36. Proposed Process for the Decomposition of Polyvinyl Chloride with Nitrogen as a Heat
    Carrier	64

37. Proposed Process for the  Decomposition of a Mixture  of Three Waste Plastics with
    Nitrogen as a Heat Carrier	65

38. Proposed Process to React Polyvinyl Chloride or a Mixture of Waste Plastics with Air	66

39. Methane Production as a Function of Temperature	86

40. Computer Program Flow Diagram	107



INDEX OF  TABLES

 1. Polyethylene Thermal Decomposition	67

 2. Polyvinyl Chloride Thermal Decomposition	68

 3. Reactor Geometry for a Waste Plastic/Nitrogen Decomposition Reactor  ..........69

 4. Nitrogen Effect on Styrene-Chlorine Reaction—Second Reactor	70

 5. Amount of Indicated Heat Source Necessary for the Specified Conversion  .........  71

 6. Mixture Reaction Products   	72

 7. Reactor Geometry for a Waste Plastic/Water  Decomposition Reactor	73

 8. Waste Plastics/Air Adiabatic Reactor	74

 9. Process Cost Summary: Polystyrene Decomposition with Nitrogen as a Heat Carrier	75

10. Process  Cost Summary:  Polyethylene Chloride Decomposition with Nitrogen  as a Heat
    Carrier	76

11. Process  Cost Summary:  Polyvinyl Chloride Decomposition with Nitrogen as a Heat
    Source	77

12. Process Cost Summary: Mixed Plastics Decomposition with Nitrogen as a Heat Carrier	78

13. Process  Cost Summary: Combustion with Air of Polystyrene or Polyethylene Waste	79

14. Process  Cost  Summary: Combustion with Air of Polyvinyl Chloride or Mixed Plastics
    System	BO

15. Process  Cost Summary: Polystyrene Decomposition with Steam as a Heat Carrier	  .  81

16. Process  Cost Summary: Polyethylene Decomposition with Steam as a Heat Carrier	82

17. Process  Cost Summary:  Polyvinyl Chloride Decomposition with Steam as a Heat Carrier   ....  83

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18. Process Cost Summary: Mixed Plastics Decomposition with Steam as a Heat Carrier	84





19. Polyethylene Decomposition	87





20. Polyethylene/NH3	88





21. Polyethylene/H20    	89





22. Polyethylene/Air	90





23. Polyethylene/Cl2	91




24. Polystyrene Decomposition	  92





25. Polystyrene/NH3	  93





26. Polystyrene/H20	94





27. Polystyrene/Air	95





28. Polystyrene/Cl2	96




29. System: Polyvinyl Chloride Decomposition	97





30. System: Polyvinyl Chloride/NH3    	98





31. Polyvinyl Chloride/H20	99





32. Polyvinyl Chloride/Air	100





33. Polyvinyl Chloride/Cl2	101





34. Variables Used in Mathematical Model	112





35. Thermal Decomposition Differential Rate Equations	114





36. Waste Plastic(s)/Chlorine Differential Rate Equations	115




37. Decomposition Products/Chlorine Differential Rate Equations	 116





38. Thermal Decomposition Products/Air Differential Rate Expressions	118




39. Waste Plastics (Solid)/Air Differential Rate Expressions	119




40. Predicted Results Compared with Experimental Results	120




41. Waste Plastics Kinetics Computer Program	 122





42. Kinetic Rate Parameters	 125








APPENDIX A: EQUILIBRIUM PRODUCT DISTRIBUTION                                          85





APPENDIX B:  KINETIC MODELS  AND PARAMETERS                                            106




APPENDIX C:  ECONOMIC MODELS                                                              126





APPENDIX D:  ASSUMPTIONS MADE IN ECONOMIC ANALYSES                                  128

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                  NEW CHEMICAL CONCEPTS  FOR
                  UTILIZATION  OF  WASTE  PLASTICS
      1. INTRODUCTION AND SUMMARY
   In June   1968,  TRW Systems  Group,  under
contract   to   the   U.S.  Department   of  Health,
Education, and  Welfare's Bureau of  Solid  Waste
Management,* undertook  a  project  to  investigate
analytically the use of waste plastic materials for the
production of high-volume process  chemicals. The
objectives of the  analysis were as follows: to identify
waste  plastic/coreactant  reaction  products  with
potential  commercial  value;  to  identify  waste
plastic/air combustion  products that are potential air
pollutants; to conceive of and provide technical and
economic evaluations for chemical  processes utilizing
waste plastics as raw materials;  and  to identify
potential R&D programs leading to the  development
of commercially viable  chemical processes.

   The approach  developed by  TRW  Systems Group
for  this  contract uses the  first  two  phases  of a
generalized  technique  for  the   development  of
chemical processes.  This  technique starts with the
formulation  of a process concept, followed by the
analysis  of  the   proposed   process   using
technical-economic   simulation  models,  laboratory
development of  the process, pilot plant operation,
and  commercialization (Figure  1). Throughout this
procedure management is provided information about
the technical  and economic implications of various
results  upon  which they can base an informed,
intelligent decision for continuing the procedure.  At
any stage, each of which calls for an increasingly large
investment, a proposed process concept is measured
against  criteria  based  on  earlier  results.  New
information on the technical and economic feasibility
is used to update the  criteria for the next stage of
development.

   In using  the first two  stages of the chemical
process   development  procedure,   TRW  Systems
analyzed the technical and  economic aspects of a
wide variety of process concepts involving the use of
waste  plastic  materials.  In  order to  provide  a
maximum amount of information at minimum cost,
the analyses of the chemical systems of interest were
performed with literature information where available
and  with estimates  where direct information could
not be found. The  technical-economic analysis was
divided   into  two  phases   as  follows:  phase  I,
thermochemical  equilibrium   analyses;  phase  II,
reaction kinetic analyses and preliminary design and
economic analyses.  Similar to  the  overall chemical
process development procedure, this division of the
technical-economic  analysis  into two phases  with
different  sections was designed to  provide decision
points to project management where the number of
systems  to be considered  in the subsequent analyses
could be limited to those demonstrating technical
feasibility at the end of the  previous analysis. This
approach converges  on those systems demonstrating
both  technical  and  economic   feasibility  for
laboratory  investigation  (Figure  2).  The  various
portions will now be  described in detail.
   "During this project, the Federal solid waste management program was a part of the U.S. Department of Health, Education,
 and Welfare, although the program is now in the U.S. Environmental Protection Agency.

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   The thermochemical equilibrium analysis (phase I)
was  initiated  with three  thermoplastic  materials,
polystyrene,  polyethylene,  and  polyvinyl  chloride,
together with five  coreactants, ammonia, hydrogen
chloride, chlorine, steam, and air, plus heat without
air.  The  various plastic/coreactant  systems  were
examined in  the gas  phase  by use  of  the TRW
chemical analysis program. The product distributions
resulting from the various systems under a wide range
of  reactant  mixture,  pressure, and temperature
conditions   were  used  for  the identification  of
commercially  important  products.  The systems in
which no significant quantities of commercial-quality
products were predicted were eliminated at this stage
of  the  analysis.  This  procedure   eliminated  the
following   two   coreactants   from   further
consideration:  ammonia,  which has  a  very  high
tendency  to  decompose;  and  hydrogen  chloride,
which  shows no tendency  to react with plastics to
form anything  other than itself. A general  approach
developed by TRW  Systems for this study was used
to  determine  thermochemically feasible  reaction
paths  for  the  remaining  chemical  systems.  This
second treatment considerably narrowed the range of
reaction  intermediates  to  be  considered  in  the
reaction kinetic analysis.
   The  management information  generated  in  the
thermochemical equilibrium analysis was used first to
limit   the   number  of  chemical  systems  to  be
considered  in  subsequent  analyses  and second to
determine the scope of the reaction kinetic analysis,
that is, the  number of species to be considered, the
products  desired,  and the  approximate operating
conditions.  The reaction  kinetic  analysis (phase II,
part   1),   which  employed   mathematical
representations of the rate relationships of the various
reactions occurring in the  chemical system of interest,
was used  to determine the product distribution-time
history  of  that  system.   The  models  and  the
parameters  contained  therein  were derived  from
current theory and the literature.  Where information
was not available, estimating techniques were  used to
provide  the   necessary  data.   The  models  were
formulated for the  computer and used to analyze the
systems of interest.

   On  the basis  of reaction kinetic analysis it was
possible  to eliminate  the  plastics/chlorine  system
from further consideration, since it was not possible
to  identify conditions  producing a  commercially
attractive product mix. Steam was  also eliminated as
a reactant although it was retained as a heat carrier.
The parameters resulting from the reaction kinetic
analysis, including residence times,  flow rates, reactor
sizing,  and heat requirements,  were provided to the
subsequent analyses.

   The   data  resulting  from  the  reaction  kinetic
analysis  were  used  to  perform the  final phase of the
technical-economic analysis, preliminary design and
economic analysis (phase II, part 2). The objective of
this final analysis was to provide information about
the  economic behavior  of the proposed chemical
process.  The analysis was based on the development
of a preliminary  process design corresponding to the
material and energy relationships of the major process
components. The various components of the process
system  were sized  by use of  data  from the reaction
kinetic   analysis.  The  operating  costs  were  then
derived in terms of depreciation, utilities costs, and
labor and used to define an "upgrading cost" per unit
of product or raw material. This information is to be
used by management  together with other data, such
as  market analyses,  to select  the processes to be
continued into the laboratory development phase.

   The  following chapters present the  approaches,
methods, and results  of the  various phases of the
technical-economic  analyses  performed  on  waste
plastic  utilization  systems. Chapter 2 presents the
general approach and analytical tools employed by
TRW  Systems  Group.  The  determination  of the
equilibrium species distributions  and  reaction path
analyses may  be found in chapter 3. Chapters 4 and 5
present  the kinetic analyses and preliminary design
and economic analyses,  respectively.  These results
provide  the   basis  for  the   conclusions   and
recommendations of chapter 6. The conclusions and

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recommendations include  not  only the  proposed
selection of processes for further application, but also
other implications, for air pollution, for example, of
the results of the TRW analysis.
            2. TECHNICAL APPROACH

   The technical approach taken by TRW Systems in
meeting  the  project  objectives  consisted  of  two
interrelated phases described  in this chapter (Figure
3).

                      Phase I

   Phase I  of the  theoretical  study of waste plastics
utilization  employed  the TRW-developed  chemical
analysis  program  (CAP).  Cap  is a  thermochemical
equilibrium computer program used to  provide  the
following information:

   1.  The  equilibrium product  distribution of  the
chemical reactions of plastics with selected chemical
reactants under various conditions

   2.  The   potential   air  and  water   pollutants
associated with each chemical  system

   3.  The thermodynamically feasible reaction paths
from  the reaction  of  plastic  materials  with selected
reagents to produce desirable end products

   The approach for the first part of phase  I was to
apply  thermochemical principles to  determine  the
behavior of plastics/chemical  agent reaction  systems.
The  following three  plastics  representative  of  the
families of plastics expected to have large-scale future
consumer usage  were investigated  in  the program:
polyethylene, polystyrene, and polyvinyl  chloride.
Chemical agents to react with these  plastics, such as
oxygen (air), and steam, hydrogen chloride, chlorine,
and  ammonia, were  selected on  the basis  of  cost,
availability, and possible reactivity with the selected
plastics.  The  TRW  thermochemical   equilibrium
program  computed  the  distribution  of  chemical
species  produced  at  equilibrium  from   specified
reactants as a function of temperature, pressure, and
reactant  composition. The program is capable  of
describing systems containing gases, pure liquids, pure
solids, and  solutions. It  requires as  inputs  only  the
chemical formulas, entropies,  and enthalpies of  the
reaction  products. Given the  selected plastics and
chemical agents,  possible reaction  products were
selected,  and  the  necessary thermodynamic data for
these  products  obtained. For  the  waste  plastics
analysis, only a small number of chemical  elements
are  involved  in  the   possible  products  as  follows:
carbon, hydrogen, oxygen, nitrogen, and chlorine.

   After all the necessary information was collected
and placed  on the program input tapes, the analysis
was conducted as follows: (1) by calculating rapidly
and inexpensively the  product  distribution  for  a
broad  range of initial compositions and temperature
and pressure  conditions;  and  (2) by examining  the
outputs  for  economically   significant   product
concentrations and potentially  harmful air  or water
pollutants.  Further   calculations  were  made   to
determine quantitatively  the effects of the reaction
conditions  on  the   concentrations  of  important
products.

   The  second   part  of  phase   I   applied  the
thermochemical computer program to determine  the
thermodynamically feasible reaction paths.  In  the
equilibrium analysis performed during the  first part
of  phase I, the  reactant  systems were  essentially
reduced  to an elemental composition  and recombined
into  the  products  according  to  thermodynamic
principles   describing  equilibrium.   It  was  then
necessary to determine if an actual chemical reaction
path could be described, that is, whether or not some
required  intermediate  reaction  step was  likely  to
occur thermodynamically.

   The   thermochemical  equilibrium program was
applied to reaction path  analysis simply by limiting
the number of products  considered at each stage  to
those that were possible  intermediates for the next
stage.   For   example,   the   polyethylene/chlorine

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coreactant  system   predicted   benzene,  methane,
hydrogen,  and  hydrogen  chloride  as  the principal
equilibrium products. The first stage of the reaction
path analysis eliminated these from consideration and
found ethane, propane, and toluene as the next most
feasible intermediates. A subsequent deletion found
ethylene,  pentadiene, butane, and other  products as
the next higher feasible intermediate stage. Following
this  stage,  ethylene  was  predicted.  In sum,  the
feasible reaction path was scoped from  ethylene  to
the final equilibrium products through two reaction
stages.

                     Phase II

   Phase  II   of  the theoretical  study  employed
mathematical models  for  describing  the  various
time-dependent  characteristics of plastics-containing
chemical reaction systems. The information generated
with  the  models   included   the   following:   (1)
quantitative data describing  the  time dependence of
various  steps  in  the reaction path;  (2) quantitative
descriptions of product  distribution as a  function of
time  and temperature;  (3)  parametric  functions
relating cost  factors such as plastics  pretreatment,
reactants  used with  the  plastics, value of products,
and reactor design and control capabilities.

   The  first task of phase II was the formulation of
the general physical and chemical properties of waste
plastics and the  waste plastics reaction chemistry into
a chemical model. This was followed by the synthesis
of a mathematical model that restated the chemistry
model  in  analytical expressions. The  mathematical
model  was translated into  an  equivalent  computer
model   that  described   the  time-dependent
characteristics of each  plastic  containing chemical
reaction system.

   The  second task of phase II was the application of
the  mathematical models developed under phase II
(part 1)  to  the  analysis of  the selected  reaction
systems. The analysis of the reacting systems required
the knowledge of (1) the reaction paths and chemical
reaction equations for each step in the reaction  path
(phase I),  (2) the parameters  describing the various
chemical and physical reaction rates at each step, (3)
the  pressure,  and   the  temperature  environment
throughout the reactor,  and (4) the flow velocity (or
residence time) in the reactor. As mentioned already,
only those  reactions that appeared important from
either  an  economic  or pollution viewpoint were
analyzed with  the simulation models. The reaction
rate parameters required to complete the description
of  the reactions  were taken  from  the  available
literature.  Where data  were  not  available  in  the
literature, they were estimated from data on  similar
systems or  calculated by use of theoretical-empirical
techniques.

   The temperature  environment  and the flow rates
through the reactors are parameters that were varied
to   determine   the  effects   on  the   reaction
corresponding to the desirable product distributions
investigated under phase  I. These conditions were
varied  to assess the effects on product distribution in
the kinetically controlled systems. The data resulting
from   the   variations  of  parameters  provided  the
necessary  information  on  the  dependence of  the
reaction on  residence time in the reactor.

   Finally,  the  data resulting from  these  analyses
were interpreted to develop relationships describing
disposal costs in terms of the reactants used with the
plastics, the value of the products, the complexity of
the reactor and  process, and  the control capability
requirements.
        3. THERMODYNAMIC ANALYSES

   The objectives of the analyses of the waste plastic
systems equilibrium were to determine the following:
the thermal decomposition equilibrium products for
polystyrene,  polyethylene, and polyvinyl chloride;
the  equilibrium   reaction   products  formed  by
combustion of waste plastics with air;  the potential
pollution  products  of waste  plastic  reactions;  the
useful products resulting from the  reactions of waste
plastics  with  other  chemical materials;  and  the

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feasible reaction paths for each system  in order to
scope kinetic analysis. The approach taken by TRW
Systems Group  to  reach these objectives  includes
application  of the chemical  analysis program  (CAP)
computer  program.  This  program is  capable  of
calculating  possible  reaction products and  reaction
paths by determining the thermodynamic equilibrium
of each system. The  principal purpose of the CAP
application  is to eliminate from further consideration
those systems  that will not yield useful products. In
addition,  CAP  is  used  to  determine for  each
coreactant system the products  that may form. The
specific  methods  of and  results for  each  CAP
application are presented in what follows.

          TRW Chemical Analysis Program
          and Thermo chemical Data Base

   Determination    of  theoretically  expected
thermochemical equilibrium  product and of reaction
path   species   distribution  requires   appropriate
thermochemical data for each potential  product. In
addition,  a  mathematical  model is  required  to
combine  these  data  in  order  to   ascertain  the
equilibrium quantities of each product. The data and
model  are   used   under  various  conditions  of
temperature, pressure, and reactant combination to
stimulate  each  equilibrium  chemical  system  and
reaction stage.

   The  mathematical  model necessary to compute
these equilibrium product distributions is embodied
in the TRW chemical analysis program. This program
is capable of simultaneously considering a maximum
of 200  gaseous products together with a maximum of
20 condensed species. The basic  variables considered
by  the program  are  the partial  pressures  of  the
elemental gases, such as  monatomic  hydrogen gas,
monatomic  carbon gas, and the total moles of gas in
the system.  These variables are used to solve a system
of simultaneous  equations, including  mass balances
for  each  element  and   a   pressure  match.  The
concentrations of the other species in the system .are
computed from the partial pressure of the elemental
gas.  The  program requires  curvefit coefficients  (a
ninth-order orthogonal polynomial is  used)  for the
standard  enthalpy and  standard  entropy  of each
species  as  a function of temperature. These data are
used  by  the  program to  determine  standard  free
energies  from   which  equilibrium  constants  are
computed for  reactions of the type

        aA +  bB  + cC + ....  A0  Bu C- ....
These  constants  are  used  in  the  mass balance
relationships  to  provide the  appropriate  weighting
factors to each elemental gas.

   The program  is capable of providing equilibrium
calculations  for  a complete  set  of thermodynamic
constraints   input  as  pairs,   as  follows:   constant
pressure, energy; temperature, volume;  temperature,
enthalpy; temperature, entropy; temperature, energy;
volume, enthalpy; volume, entropy; enthalpy, energy;
and entropy, energy. The program accepts the weight
percents of the various reactants  together with their
molecular  formulas  and  enthalpies  of formation.
Other data, such as T and P, are input corresponding
to the constraints. The quantities  of each element
(100  g total system being assumed) are computed and
species  corresponding  to  the   combinations  of
elements selected from the thermochemical data tape.
The mass balances are set up for each element and the
equilibrium   compositions  computed   under  the
stipulated thermochemical constraints.

   The equilibrium  distribution  is computed  only
among the species selected from the thermochemical
data tape. Under the normal operating mode, data for
all listed potential products of the reactant elements
are selected from the species tape. The program is,
however,  designed to  accept  specifications on the
product list  considered, allowing specific  deletions
and selections of potential products.  The classes of
problems  that  can   be  analyzed  are,  therefore,
expanded  to include competitive reaction analysis as
well as general system equilibrium.

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   The  proper  use  of  the  mathematical  model
requires accurate data describing the thermdchemical
behavior of the various species considered as resulting
from  the  reaction  of the  starting  materials. The
thermochemical data required by the TRW chemical
analysis program for the waste plastic systems are the
enthalpy and entropy  as  a function of temperature.
These  data  are used  not  only  to  compute  the
necessary  equilibrium constants but also to provide
the   information  necessary   to   satisfy   the
thermochemical constraints.

   The primary  data base used by the TRW chemical
analysis  program   was  provided  by  the  JANAF
thermochemical  tables  prepared  by  the  Dow
Chemical  Corporation.    These   data  include
information on a  broad range of chemical species
containing  a  very  representative  selection of  the
common  elements.  The  JANAF  tables emphasize
species  that could  be significant in chemical rocket
exhausts.  Since rocket conditions are  very severe,
complex organic molecules are  unlikely and are  not
included.

   In  order  to perform  an adequate equilibrium
product  distribution analysis,  it  was  necessary  to
develop  a  thermochemical   data  set  containing
additional  species  representative  of  the  products
expected  under  the  less  severe  conditions
characteristic  of  industrial  reactors.  The  JANAF
tables  include  the  potential  products   methane,
acetylene,  ethylene, ethylene  oxide, formaldehyde,
and the various methyl chlorides among the organics;
no higher organics are represented. Data for classes of
compounds were required to represent the products
expected  with  the  waste plastics coreactants. The
classes are the following:

       (1)  higher saturates, e.g., ethane;
       (2)  higher unsaturates, e.g., propylene;
       (3)  alcohols;
       (4)  glycols;
       (5)  higher aldehydes, e.g., acetaldehyde;
       (6)  ketones;
       (7)  ethers;
       (8)  higher chlorides, e.g., ethyl chloride;
       (9)  amines;
      (10)  higher epoxides, e.g., propylene oxide;
      (11)  aromatics.

   Data for the first two classes were available from a
compilation  prepared by  the American  Petroleum
Institute Project (API) 44.2 The thermochemical data
selected  were  limited  to compounds  having six
carbons in the case of aliphatics and nine  carbons in
the case of aromatics since higher molecular weight
materials are not found in significant quantities under
the conditions planned for study.

   Heat capacity (CP) data for some of the alcohols,
glycols,  aldehydes,   chlorides,   and epoxides  were
available from the recent compilations prepared by R.
W.  Gallant   and  published  in   Hydrocarbon
Processing.-1'^ In order to compute  the necessary
enthalpy   and  entropy   data   as  a  function  of
temperature, data for  the enthalpy  of  formation
(H°f 298) and entropy at 25 C (S°298) are combined
with the heat capacity data. These data were obtained
from the  literature when  available. ^'   Data not
available from these sources were estimated with the
techniques of S.  W. Benson.  •*  A computer program
was  written for the  TRW time-sharing  system to
compute  the appropriate   enthalpies  and entropies
from the  heat  capacity,   heat  of formation,  and
reference entropy data.

   Data for the ketones, ethers, amines and certain
compounds of interest in  the other classes were not
available   in  compiled  sources;  therefore,  the
technique of S. W. Benson was again used to estimate
heat  capacity  as well  as heat  of formation  and
reference  entropy.  ^ Whenever possible,  computed
data were compared with individual data available in
the literature. The estimated data were used together
with  the   time-sharing  program  to   generate  the
necessary entropies and enthalpies.

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     Equilibrium Product Distribution Analyses

   The  purpose   of  the   equilibrium   product
distribution   analyses  is  to   provide   a  sound
thermochemical basis  for  the  determination of the
species resulting  from the reaction of waste plastic
materials  with  various  coreactants.  Three  plastic
materials, polyethylene,  polystyrene, and polyvinyl
chloride,  were  considered  with  five  coreactants,
hydrogen chloride, ammonia, water, air, and chlorine,
as   well  as  with  no  coreactants  (thermal
decomposition).  In   the  following  sections  the
products resulting with each coreactant are discussed
with emphasis on the general  characteristics of the
reaction  systems. The numerical results  for  each
system  and   the   equilibrium  chemical   species
considered were summarized (Appendix A).

   Thermal Decomposition Reaction  Systems. The
equilibrium product distributions resulting from each
of the three  plastic systems were examined at two
pressures,  68 and  1  atm, and three temperatures,
1,472, 1,073, and 773  K. Thermal decomposition
provides  a basis for comparison of the effects of the
coreactants on the product distribution. The primary
products produced at equilibrium for the three plastic
types vary with carbon-hydrogen ratio in the original
plastic material (Figure 4). The relative amounts of
the various products naturally vary also as a function
of  temperature  and pressure—the amounts  of the
unsaturated   aliphatics  increasing  as   temperature
increases  and  decreasing  with increasing pressure.
Benzene  appears to  be  particularly  favored in the
polystyrene  and polyvinyl  chloride  systems. The
polystyrene (CgHg)n  is stoichiometric  to benzene,
and  the  polyvinyl  chloride  (CH2CHCl)n  is also
stoichiometric to benzene if  hydrogen  chloride is
formed.   Under   the  temperature   and  pressure
conditions   considered,   the   polyethylene   system
indicated a  tendency toward  dehydrogenation  to
acetylene and benzene. At temperatures  lower than
those examined in the analysis, it  would be expected
that  ethylene would  become  the  most  favored
decomposition product.
   Hydrogen Chloride Reaction System. The set of
pressure-temperature conditions used for the thermal
decomposition was the basis of comparison  for the
subsequent analyses.  The hydrogen chloride system
represented  the  first  coreactant analysis. For the
analysis, reactant concentrations were  chosen such
that  complete reaction  would  not  result in  large
excesses of the initial materials since excesses tend
greatly  to  promote kinetic  rather than equilibrium
effects. The concentrations selected were 70 weight
percent polymer/30 percent  coreactant, 50 percent
polymer/50  percent  coreactant,  and  20  percent
polymer/80 percent coreactant.

   The  hydrogen chloride systems analyses indicated
that hydrogen chloride  does not react  significantly
under the conditions examined, primarily because of
the  favoring  of equilibrium  toward the  aromatic
compounds (Figure  5). The product distribution is,
therefore,  essentially  the  same  as  is  seen  in the
thermal  decomposition   analysis.  It  is  possible,
therefore,  to  eliminate  this  system from  specific
consideration.

   Ammonia   Reaction   Systems.   The  ammonia
systems were examined  to indicate  whether  arnine
compounds were feasible products from  waste plastic
reactions.   Under  equilibrium  conditions  at  the
compositions, pressures,  and temperatures selected,
the   analysis  showed  that  ammonia  formation
equilibrium
           N2  + 3H2         2NH3

was  completely reversed  supplying free  hydrogen to
the system (Figure 6). The  hydrogen released  from
the ammonia severely decreased the concentrations of
the  unsaturated  compounds,  both  aliphatic  and
aromatic.   The  most   significant  organic reaction
product under these conditions is methane.

   The  production  of  methane  from  the  waste
plastics/ammonia  systems is not  an economically
significant result. Ammonia is prepared commercially
by  a  process  including  the  partial oxidation  of

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methane or other saturated hydrocarbon with air to
produce hydrogen  and nitrogen,  which  are  further
reacted to give ammonia.  The results of the ammonia
equilibrium  analysis  further  indicate  that  direct
hydrogenation  would also be economically  limited
since   the   hydrogen  is  produced  from  similar
reactions.

   Water  Reaction   Systems.   The  water   (steam)
coreactant  systems  were  investigated primarily to
determine  whether  partially oxidized  compounds,
e.g.,  alcohols,  were  potential products  of waste
plastics   utilization.  The   equilibrium   product
distributions were  computed  under  the  previously
stated environmental and compositional conditions.
Partially oxygenated product types represented in the
calculations   included  alcohols,   glycols,  ethers,
aldehydes,  and ketones in addition to  the  various
carbon oxides.

   Under  the   conditions  studied,  no  significant
quantities of the various oxyorganic compounds were
found in the major product  distributions (Figure 7).
The analyses indicated, however,  the potential  of a
steam reforming reaction system's producing carbon
monoxide  and hydrogen  with the waste plastics. A
steam-fed catalytic reactor could  eliminate the bulk
plastic and produce reducing gas products.  Recovery
equipment  would  be  necessary  to  collect  the
hydrogen  chloride   generated  by   the   polyvinyl
chloride system.

   Air Reaction Systems. The steam reaction system
represents  a relatively inexpensive reactant that when
combined  with waste plastics might have  economic
potential as a disposal technique.  The air reaction
system  described in  this section also  uses a  very
inexpensive reactant. The purposes of this  analysis
were twofold. First, the systems were  examined to
indicate conditions  that limit  the formation of
products,  representing  a   potential  air  pollution
hazard. These analyses are concentrated on a current
technology used in  many places  to  eliminate  bulk
waste, substituting a potential pollution problem for
the immediate bulk waste disposal problem.

   Commercially  significant  products   for  these
systems are absent  in the temperature-pressure  and
composition ranges examined (Figure 8). The primary
products  are  the  expected combustion products;
however, certain potential pollutants are indicated in
the  analyses.   In  the  fuel-rich  combustion range
examined,  the equilibrium analyses show significant
quantities of hydrogen cyanide gas, HCN, present in
all  the  plastics  systems. Temperatures higher than
those examined show a  further preference for  this
product.  This  would  indicate  that  the   reactor
(combustor) design  used for the burning of plastic
materials  must  include  specific  provision  for   the
adequate  mixing  of the reactants  eliminating  hot
spots in fuel-rich zones.

   A second  potential pollutant  whose  quantity is
dependent only upon the original quantity of plastics
is   hydrogen  chloride  gas, HCl,   produced  from
polyvinyl chloride. Its presence indicates that plastics
combustion equipment must have provision for  the
recovery of this gas,  which certainly is  comparable
with the sulfur  oxides in potential corrosive effects
on biological,  metallic, and other systems exposed to
it.

   Chlorine   Reaction   Systems.  Chlorine   gas
represents  a  relatively expensive  reactant  but  one
whose reactivity  was considered likely  to  produce
economically  significant products. Organic chlorides
have found a wide variety of commercial applications.
The  chlorine/plastics  systems  were  examined in
equilibrium under the usual conditions  in  order to
predict  the product  mix obtained (Figure 9). As was
expected,  significant  quantities  of chloro-organic
products  were   predicted   under   equilibrium
conditions. The simulation of the  chemical-kinetic
behavior  of  these systems  defined  conditions  that
allowed chlorine to produce several different chlorine
derivatives.

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              Reaction Path Analyses

   The purpose  of this analysis was to determine the
general  types of possible thermodynamically feasible
intermediate species for each chemical reaction. The
resulting information  from this analysis was used to
scope  the   chemical-kinetics  model.  A separate
analysis from that of the equilibrium results reported
earlier is  necessary  since  its  data are  calculated  by
reducing  the  reactant system  to  elements and
recombining  them   into   products  according  to
equilibrium  thermodynamic principles.  Calculations
of this type give no hint about the possible reaction
paths and species to consider. Possible intermediate
species at a given step are  identified by rerunning the
equilibrium  program and   deleting   all   major
equilibrium products found by the previous run.

   Significant   products   are  formed   from
polyethylene, polystyrene, and polyvinyl chloride by
reacting them thermally and with the coreactants  air
and  chlorine. These system paths  and  their possible
intermediates were studied, and the results are now
reported.

   Thermal Decomposition Reaction Path Analysis.
The  polystyrene thermal decomposition  equilibrium
results indicate  that benzene is in equilibrium with
styrene  at   1,073  K  and  1  atm  pressure.  This
equilibrium  mixture represents  a minimum  of the
relative  system's free  energy, or in other words the
most probable distribution of species at equilibrium.
When benzene is not  allowed to  form,  the reaction
yielded a new product  distribution (Figure 10), which
represents a higher system's free  energy. This result
may be interpreted  to mean that these products are
similar  to the actual  intermediates in the benzene
from polystyrene reaction.  The possible intermediates
include  toluene, the  cis-trans 1-phenyl-l-propylene
and the ortho-meta-para methyl-styrene.

   Polyethylene equilibrium results, like polystyrene
results,  predict  conversion of the given plastic  to
benzene at  773 K and 1 atm. The feasible reaction
intermediates are,  however,  for  the  most  part
different (Figure 10). Toluene is the only species that
appears in both cases. In addition to  toluene, the
feasible  intermediates  include   ethane,   propane,
e t h y 1 - b e n z ene ,    and   ortho-meta-para
dimethyl-benzene.

   The  major  coproducts   of   the   thermal
decomposition of polyvinyl chloride at 773  K and 1
atm pressure are benzene and hydrogen chloride. This
is  similar   to  the  polystyrene  and  polyethylene
decomposition, except that no hydrogen chloride can
be formed in the  first two systems.  The polyvinyl
chloride  decomposition path  analysis consisted  of
two  equilibrium runs, the first excluding  benzene
from  forming. The results of this run indicate that
chlorine-substituted  ethylenes  and   toluene  are
formed.  A second run  deleting  these as  possible
products yielded ethyl benzene as the next level of
feasible product.

   Air-Plastic Reaction Path  Analysis.  The reaction
path   analyses  for the  determination  of  feasible
intermediate  species  for  the air-plastic  reactions are
presented  in   this  section.  As   in   the  thermal
decomposition equilibrium analysis and reaction path
analysis, benzene  is  one of  the  major coproducts
formed from  the three waste  plastics (773 K, 1 atm,
and with 70 percent plastic material and 30 percent
air by  weight).  In  addition to  benzene,  carbon
monoxide, carbon dioxide, and methane are formed
at equilibrium from the polystyrene-air system. When
these  products  are  not  allowed  to  form  in the
polystyrene system, toluene appears to be the next
most  feasible  product. After all previous products are
deleted,  the  styrene  monomer is  the  most feasible
species (Figure 11).

   Polyethylene-air  reaction   equilibrium  products
include hydrogen  as well  as those products found in
the polystyrene-air reaction   system  under similar
conditions.  Although  the  equilibrium  results are
similar, a  number of differences  are  found in the
distribution  of  feasible   intermediate species.  In
addition  to toluene, which is found in both  systems,
propane, ethylbenzene, and ortho-meta-para-dimethyl

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benzene  are  formed.  When  these  are  excluded,
propylene, ethanal, and dimethyl ketone are found to
comprise the next  level of feasible products (Figure
11).

   The polyvinyl chloride equilibrium  products are
similarly  distributed to  those previously listed except
that in  place  of  hydrogen, hydrogen chloride is
formed. The first level  of feasible products includes
toluene and styrene. After deletion of these products,
ortho-meta-para methyl-styrenes and xylenes, and
ethanal become feasible  products (Figure 11).

   Chlorine Reaction Path Species Analysis. Reacting
polystyrene with chlorine  at 773 K, 1 atm, and 70
percent plastic to 30 percent chlorine  (on a weight
basis)  results in the reaction products benzene  and
tetrachloroethylene  with  hydrogen  chloride  as  a
coproduct  (Figure  12).  The  styrene  monomer
comprises a secondary level of feasible materials when
the previous product formations are suppressed. After
styrene,  the next level  of feasible products includes
toluene and tetrachloroethane.

   The  polyethylene  reaction  path  equilibrium
analysis  identified  benzene, methane, and hydrogen
along with hydrogen chloride as the major products.
These  were formed at 773 K, 1 atm,  and 70 percent
polyethylene by weight. After suppression of the
products,  a  rerun  of  the  chemical  equilibrium
program  predicted  ethane,  propane,  and toluene as
the  next  set  of  feasible intermediates.  A second
product   suppression  and   rerun   yielded  1,4
pentadiene; 1,3 butadiene; ethylene; and butane as
feasible intermediate products.

   The final path analysis studied polyvinyl chloride
and chlorine reacting at 773 K and  1  atm pressure
with  a mixture of 70  percent by weight polyvinyl
chloride  to chlorine. The final equilibrium  mixture
under  these  conditions  gave  methane,  benzene,
tetrachloroethylene,  and  hydrogen  chloride   as
products.  Feasible  intermediate  products included
toluene,   the  three isomers   of  dichloroethylene,
isomers  of tetrachloroethane,  and ortho-meta-para
dimethylbenzene. A rerun of the equilibrium program
gave  styrene  as a  feasible intermediate after  all
previous major products were suppressed (Figure 12).

             4. KINETIC ANALYSES

   Phase I of the waste utilization program was based
on  the  application   of   a  TRW-developed
thermochemical equilibrium computer program. This
program determined  equilibrium  reaction   species
concentrations resulting from chemical  reactions of
plastics  in various environments.  In addition,  the
program selected thermochemically feasible reaction
paths from  the total  number  possible.  The  kinetic
analysis expanded the phase I  equilibrium data base
by  determining residence times, flow rates, reactor
sizing,   and  heat requirements for  each  system.
Emphasis of  the kinetic analysis  was  placed  on
identifying reaction systems of an economic potential
that would lead to the development of commercially
attractive chemical processes. The primary purpose of
the kinetic analysis is to provide time-dependent data
resulting in  a  consistent characterization of  each
system.

   The information compiled from  phase I and from
the literature  was used to delineate  those reactions
and reaction  mechanisms  that  would  yield  the
identified  final  products.  The   reactions   were
combined  with  a  heat  and   material  balance  to
complete the chemical-kinetics  model. In some cases,
the  rate  parameters,  and  the  enthalpy  and  heat
capacity data for the models were not obtainable. For
these, the data were estimated by methods developed
by  Benson. 15  This   information  resulted  in  the
formulation of  mathematical models describing the
time and temperature behavior of chemically reacting
waste plastic systems.

   Following the formulation stage, the models were
programmed  into  equivalent   computer  programs
capable  of  simulating  a  broad range  of operating
conditions.  The  resulting computer  programs  were
used  to simulate the  process  unit  operations for
determining technical-economic characteristics of the
                                                   10

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total  system.  The  results  of  these  analyses are
interpreted in  terms  of the following:  cost  factors
associated   with   various   reaction   processes,
performance  criteria  necessary  for research on new
reaction process concepts, and the design of chemical
reactors   capable  of  providing  desired  product
distributions.

   The results of the polystyrene, polyethylene, and
polyvinyl  chloride  thermal decomposition  kinetic
analyses  using nitrogen gas as the heat source are
presented   now,   followed  by  the  waste
plastics/chlorine  gas  coreactant  analyses  and the
coreactant system analyses of the three waste  plastics
with water and with air.

      Thermal Decomposition Kinetic Analysis

   The approach for the kinetic analysis of thermally
decomposing  polystyrene,   polyethylene,   and
polyvinyl chloride waste  plastics  consisted  of the
following: (1)  determining the physical and chemical
properties of the reactants,   (2) determining the
decomposition  mechanism,   (3)   formulating  a
chemical  model, (4)  translating the chemical model
into a mathematical  model,  (5) programming the
mathematical  model  into  an  equivalent computer
program,  and  (6)  simulating  each reaction  system
under  various reaction  conditions. The results are
presented as  concentrations of reaction products and
nitrogen gas (heat source) as a function of time. From
these   data  the   reactor  geometry  and  heat
requirements were defined.

   Polystyrene. The  kinetic behavior of a chemical
system is strongly  dependent upon the physical and
chemical properties of the reactants. In order  to treat
realistically these time-dependent characteristics of
the  polystyrene   decomposition   reaction,   the
following physical and chemical properties of waste
polystyrene   were  postulated  from  information
reported  in  the  literature: (1)  polystyrene waste
plastic contains thermally active sites ("weak  links"),
which are randomly distributed within each molecule;
(2) waste polystyrene is heterogeneous with  respect
to initial  chain  size;  (3) the reactant plastic can be
characterized by an initial "most probable" molecular
weight distribution; (4) plastic fed to the reactor is
selected at random, that is, no distinction is made on
the  basis  of degree  of  polymerization,  molecular
weight, etc;  (5)  it is  homogeneous  with respect to
monomer type, i.e., polystyrene only.

   Initially,   the  decomposition  of  commercial
polystyrene occurs by a random mechanism owing to
weak links formed  in the polymerization  reaction.
When a weak link is broken, a number of monomers
are split off. This phase continues until the weak links
are  exhausted.  During  this  rapid  initial  period,
inhibitors are produced to give rise to an induction
period that is very pronounced at 625 K and below.
Above  675  K  the induction  period   is  not
experimentally evident for either unfractionated or
fractionated samples.

   A depolymerization reaction occurs at the end of
the  induction period  by the following mechanism:
chain  end  initiation  reaction,  transfer  reactions,
propagation reaction,  termination reaction. Transfer
reactions are at a trace level for temperatures between
700  and  1,000  K,  which  means high  styrene
monomer yield with 100 percent selectivity.

   This chemical model was reformulated in terms of
a  mathematical   model   that  describes  the
time-dependent  or kinetic behavior of waste plastic
chemical  reactions.  It  is composed  primarily  of
systems   of   interdependent   ordinary  differential
equations. For  waste  plastic thermal  degradation
models, these equations describe the rates of product
formation as a function of time and distance within a
chemical  reactor. Usually, these  equations  can  be
solved  numerically  only  by  high-speed computing
machines. It is for this reason that the waste plastic
mathematical  models  are coded  into equivalent
computer  programs.  The  computer programs are
written in a  general  format in  order  to  facilitate
conversion from  one set  of  differential  equations
describing polystyrene into another  set describing
either polyethylene or polyvinyl chloride.
                                                   11

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   The  grams  of styrene  produced  per  gram  of
polystyrene as a function of the solid residence time
(that is, the residence time of the solid waste plastic
material)  were  computed  for  a broad range  of
temperatures (Figures 13, 14, and 15).  As expected,
the higher  the  temperature  the faster the  rate;
however, the increase in rate must be balanced against
heat requirements. The  heat necessary to maintain an
isothermal reactor is  supplied by hot nitrogen gas that
is preheated to 1,500 K. At 92 percent conversion the
reactor requires a total of 15.5 g of nitrogen per gram
of styrene when the initial nitrogen is 1,500 K. This
may be compared with 82.0 g of nitrogen per gram of
styrene at 1,000  K initial nitrogen temperature. The
quantity  of nitrogen (at 1,500 K) required per gram
of  styrene   produced  increases  with  reactor
temperature at fixed  conversion (Figure  16). The
economies in nitrogen gas at the higher conversion are
due  to the fixed  amount of nitrogen  (1,500  K)
required  to bring the  waste  plastic from ambient
temperature to reactor temperature.

   The   reactor  residence  time-heat   requirement
tradeoffs, the  required  conversion, and the physical
properties of unreacted waste  plastic  dictate the
necessary solid residence time and as  such the total
volume. From this, an economical reactor system and
associated process were designed and used to estimate
the  costs  for  processing each pound of  waste
polystyrene.

   Polyethylene.  As expected in  a kinetic study, the
physical/chemical properties  of  waste  polyethylene
are important  in characterizing its time-dependent
nature.    Spectroscopic  investigations    show  that
polyethylene is not  strictly a  straight polymethylene
chain but contains  methyl, carbonyl,  and peroxide
groups.  Moreover,  it  has  been  determined that
polyethylene  is  branched  with  one   branch point
present on  the  average for every 50 carbon atoms.
Additional physical  properties  of waste polyethylene
are equivalent to the ones listed for polystyrene. The
decomposition reaction mechanism for polyethylene
proceeds, however, in a different  fashion from that of
polystyrene. Polystyrene  degrades into  monomer
styrene between  700 and 1,000 K. Reaction products
resulting from polyethylene contain  little monomer
but primarily paraffins with as many as 50  carbon
atoms,   depending  on   the  temperature.  The
degradation reaction for temperatures between 660
and 710 K appears  to be  of zero order over a large
range  of  percent  weight  loss.  The   mechanism
probably  consists  of splitting off large  molecular
fragments  in  rapid  succession once the  chain is
initiated.

   After the chemical and  mathematical models were
derived,  the  necessary   simulation  model  was
programmed  and an analysis was completed that
characterized  the  system.  The quantity  of product
produced  versus  residence  time  with a polymer of
822 average degrees  of polymerization varies strongly
with temperature (Figures  17 and 18). Temperatures
between 685 and 710 K were found to be practical
reactor  temperatures, heat input requirements and
residence  times being considered.  Complicating the
analysis is the fact  that the rate  was found to  be
affected by  the  average  degree of  polymerization
(ADP).  Inasmuch as it  is  impossible to  determine
waste polyethylene ADP a priori, its effect must be
considered parametrically  in designing the reactor.
The effect of ADP over a range of 571 to 3,000 units
was examined in  the present study (Figure 19). As in
the  polystyrene  analysis,   the heat  versus rate  or
conversion was studied for the reaction design (Figure
20).  The   product distribution for  a  polyethylene
thermal degradation system was calculated  at 710 K
(Table 1).  The relative concentrations of species are
approximately constant at each conversion.

   Polyvinyl  Chloride.   Polyvinyl  chloride  is
essentially  a   linear polymer  of  "head  to  tail"
configuration. A small amount of branching is present
composed  probably of carbon and  chlorine  atoms.
The  general properties of  waste polyvinyl chloride
material  are   the  same   as  those  presented  for
polystyrene.

   The  thermal degradation of polyvinyl chloride is
primarily   a  dehydrochlorination reaction.  After a
short initial  period, hydrogen chloride  is evolved
under a mechanism of approximately 3/2 order in the
                                                   12

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fraction of undegraded  units. Following  hydrogen
chloride evolution, a secondary decomposition occurs
that yields numerous organic products (Table 2). The
effects  of temperature on the hydrogen chloride and
on  the hydrocarbon  reaction  were  examined to
determine  feasible reaction  conditions  (Figures  21,
through 24).  The  net  result is  that the reaction is
commercially  feasible above 675  K.  The  hydrogen
chloride and  hydrocarbon  product  evolution  was
examined  as  a  function of solid  residence  time
(Figure 25), 723 K being selected as the nominal case.
Here the  hydrogen  chloride  is  the   predominant
product at all residence times. The overall reaction is
exothermic  owing to  the   predominance  of   the
exothermic  hydrogen   chloride  stage   over   the
endothermic  organic  evolution  stage.   As  such, no
nitrogen is required after the initial 1.2 g/g of waste
plastic  polymer necessary to  raise the temperature
from 300 to 723 K.

    Thermal   Decomposition  Preliminary  Reactor
Designs.   The   thermal   decomposition  reactor
 mathematical  models  were  based  on engineering
 design  of a semicontinuous  moving-bed reactor. The
 reactors are to be operated isothermally by supplying
 "hot"  nitrogen  gas at  various  points within  the
reactor. Waste plastic is fed continuously from above.
Any unreacted material is removed in a batch fashion
by switching to auxiliary  reactors.

    Resulting data from the reactor models are used to
develop relationships  describing plastic-processing
costs as a  function of coreactants, value of reaction
products,  capital  costs   and  operating  costs.  A
schematic  diagram of the  designed plastic thermal
decomposition reactor was prepared (Figure 26), and
the specific dimensions of the reactor for each of the
decomposition systems were summarized (Table 3).

      Waste Plastics/Chlorine Kinetic Analysis

   Polystyrene. This section  describes the results of
the polystyrene/chlorine  kinetic analysis.  Reactions
of polystyrene waste plastic and chlorine  gas were
kinetically  simulated  with  two   different reactor
configurations. The first configuration consisted of a
two-stage reactor; the first reactor used hot nitrogen
gas to decompose the polymer thermally, followed by
a  second reactor that reacted the  monomer with
chlorine  gas  (Figure  27).  The second configuration
consisted of  a  single  reactor  using  chlorine  gas
reactant  as the heat carrier. This reactor is equivalent
to  the  thermal  decomposition  reactor  presented
earlier  (Figure 26).

   Kinetic results of the  first-configuration second
reactor  indicated  that   the   monomer/chlorine
reactions proceed slowly  in  the  presence  of excess
nitrogen. .A  modification  to this configuration was
proposed whereby nitrogen was  removed before  the
second reactor. Subsequent analyses  calculated more
favorable kinetics. In  addition,  the volume of  the
second reactor without nitrogen was found to be
approximately 3 percent that of an equivalent reactor
with  nitrogen  at equal conversions.  The  product
analysis  of the  second reactor  (Table  4)  and  the
product  produced per gram reactant (Figure 28) were
calculated for  both  systems  (with  and  without
nitrogen at 900 K).

   The second  configuration  consisted  of a single
reactor where polystyrene reacts with  chlorine  gas
directly. Here chlorine acts as the heat source as well
as the  coreactant. The kinetic analysis of this reactor
indicated  an  almost  total  conversion  of  waste
polystyrene gas phase products to hydrogen chloride
and   heavily   chlorinated   styrene   with  some
chlorinated toluene and methane derivatives.

   From a kinetic or reaction control standpoint, the
practical  system would be the  first configuration,
where  chlorine gas is reacted with styrene monomer
after   the  nitrogen-waste  plastic  decomposition
reaction  (first reactor) and after nitrogen removal.
Further  analyses of this two-stage reactor  indicated
that   increasing  chlorine/styrene  ratio   (or
temperature) favors formation of (ortho, meta, para)
1,2   dichloro-ethyl   chlorobenzene   over  1,2
dichloro-ethyl benzene  as the major  product  (Figure
29). Both systems were found to be impractical from
                                                    13

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an economic and product yield point of view (see
what follows).

   Polyethylene  and  Polyvinyl  Chloride.  Kinetic
analyses  similar to the polystyrene/chlorine  analysis
were  completed  for  polyethylene  and  polyvinyl
chloride  waste  plastics reacting with chlorine. Both
waste  plastic  systems were  modeled  with the two
configurations already described.

   The results of these analyses were analogous to the
results reported in the previous section, where  the
two-reactor configuration was found  to  be  favored
from  a process control standpoint. Various mixtures
of hydrocarbons and chlorinated hydrocarbons could
be  produced  by  varying  feed  concentrations  of
nitrogen   and  chlorine.  The  second  configuration
(single reactor) gave hydrogen chloride as the  major
product for both plastics. In addition, the  mixed-feed
alkane-alkene  stream of  polyethylene produced  a
mixture  of carbon tetrachloride,  hexachloroethane,
etc., whereas chlorinated toluene  and styrene, along
with  carbon tetrachloride,  hexachloroethane,  etc.,
were  produced  from   the  polyvinyl  chloride
decomposition stream.

   The    general  usefulness  of   the   waste
plastic/chlorine  system  is  limited  by the fact that
chlorine reactions are not very selective. All types of
alkane hydrogens  are attacked  with almost  equal
probability. Introduction of one chlorine atom does
not  appreciably  affect the  replacement rate of  a
second or third, etc., hydrogen atom. The net result is
that all  possible  products  are obtained when  the
reaction  is chlorine limited. Excess chlorine replaces
all available alkane hydrogens at a very rapid rate.

   In summary, kinetic analyses of the three waste
plastic/chlorine coreactant systems demonstrated the
usefulness of the two-reactor configuration from a
control  or  final  product  standpoint.   From   an
economic point of view, however, this configuration
is unfavorable, since it requires the heating of waste
plastic to the decomposition temperature followed by
cooling to  remove  part  or  all of  the nitrogen.
Subsequently, the stream must be reheated to react
with  chlorine.  Most  importantly, the  value  of the
final chlorinated products (including upgrading costs)
is less than  the value of the thermal decomposition
products.  Commercially,  it would  be possible  to
hydrolyze the  mixed chlorides  to  produce  mixed
alcohols.  Reactions  with  ammonia   would yield
amines  and with  sodium hydrosulfide would yield
mercaptans  and  sulfides. For reactions  such as these
to be commercially rewarding, a market for these
chemicals would have to be identified.

        Waste Plastics I Steam Kinetic  Analysis

   Presented in  this  section are  the results  of the
kinetic   analyses   of  polystyrene/steam,
polyethylene/steam,  and  polyvinyl chloride/steam
digestion systems. The objective of these studies was
to  determine  the  feasibility  of  using  steam-fed
reactors to  eliminate bulk waste plastics  and supply
products valuable for fuel. Results indicate processes
could be  designed for thermal decomposition using
steam  that  would   be   more  economical  than
corresponding   waste   plastics/nitrogen   thermal
decomposition systems.

   Waste  plastics/steam   digestion  systems  were
analyzed with use of equilibrium thermodynamics in
phase I of  the waste plastics  utilization  study. The
purpose was to determine whether partially oxidized
compounds  such   as   alcohols,   glycols,   ethers,
aldehydes,  and  ketones were  potential products.
Results  of  phase  I  showed  that no  significant
quantities of these chemicals will be found under the
conditions studied. They did,  however, indicate the
potential   of  steam-reforming   reaction  systems'
producing  carbon  monoxide  and hydrogen. These
reforming systems were  not  kinetically simulated,
since  the reactor  would   require   a   catalyst
development that would be outside  the scope of this
study.  A system  without catalysis was,  however,
modeled that would thermally decompose the bulk
plastics with steam as the heat source.
                                                   14

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   The analyses  of the waste plastic/steam systems
without catalysts gave kinetic results similar to those
of  the waste  plastics/nitrogen systems in that the
product distributions  were essentially the same for
each system. There are however, advantages in using
steam  as a source of heat in place of nitrogen.  This is
due to the larger heat capacity of steam as compared
with   nitrogen,  which  reduces  the  carrier  gas
concentrations, and hence, the  reactor gas volume.
For example,  the  polyvinyl chloride decomposition
reactor operating isothermally at 723 K requires 0.9
mole of nitrogen at 1,500 K as compared with 0.7
mole  of  steam  at  1,500  K.  A   nitrogen/steam
comparison was  calculated for a variety  of thermal
decomposition systems and conditions (Table 5).

   A fourth waste plastic/steam system was simulated
wherein an  equal-weight  mixture   of  polystyrene,
polyethylene, and  polyvinyl chloride was fed  to the
reactor. The  product distribution  (Table  6),  the
reactor design  (Figure 30), the geometries (Table 7),
and steam (as a heat carrier) requirements (Figures 31
and 32)  were  calculated  for  the  composite feed
system as necessary for the economic  analysis.

         Waste Plastics/Air Kinetic Analyses

   The phase I equilibrium analysis and reaction path
analysis indicated  the possibility of reacting waste
polystyrene,  polyethylene, and polyvinyl  chloride
with air. From the point  of view of the technologic
and economic importance  of hydrocarbon oxidation,
the air oxidation of waste  plastics was considered an
important  system  for analysis.  The utilization of
oxidized waste plastics could be important in  two
separate applications as follows:  partial oxidation to
synthesize important  industrial  compounds,  and
complete  oxidation to produce energy. In this light,
the waste plastics/air reactor  systems were modeled
for an adiabatic  reactor and an isothermal reactor
with two configurations.
   The  adiabatic reactor system was  simulated to
determine the value of using waste plastic materials as
a  source  of energy.  Four  separate  systems were
simulated  as   follows:   polystyrene/air,
polyethylene/air,  polyvinyl  chloride/air,  and  an
equal-weight mixture  of the three  plastics with  air.
The system  consisted  of an adiabatic  reactor with
plastic material and air input at ambient temperature
(298 K). A preliminary kinetic analysis  indicated the
lack  of  usefulness  of  rate  data  (by  itself)  for
determining reactor geometry.

   For  the  waste  plastic systems  considered,  the
observed products are  very near equilibrium  for any
reasonable reactor  geometry. For  this  reason,  the
complete  simulation   model was  not  formulated.
Rather, the preliminary kinetic analysis was expanded
by use of the CAP program to determine reactor heat
requirements.   These   requirements   along  with
estimated  heat  transfer  coefficients   allowed  the
determination of a heat transfer area. As is customary
with  combustion reactors,  the  preliminary  reactor
design and estimated costs are based on this surface
area.  A preliminary reactor  design was  prepared for
the  waste  plastic/air  system (Figure  33),  and  the
product  distribution, reactor exit temperature, and
air input were calculated  for the four systems (Table
8). Polystyrene and polyethylene yielded heat value
products; polyvinyl chloride and the mixture yielded
heat value products and hydrogen chloride.

   The  isothermal  reactor  was  modeled  in  two
separate   configurations.   The   first  configuration
consisted of a single  reactor using  air as the heat
source  as   well  as   the  reactant.  The   second
configuration consisted  of  two  reactors; the first
reactor  thermally  decomposes  waste   plastics into
products, using nitrogen or steam as  the heat source.
Following  this reactor, a second reactor is used to
react  the decomposition products with air under mild
conditions. The first configuration was  found to be
impractical  from a  reaction  control standpoint. In
addition  to the all but uncontrollable heat transfer
problems, local hot spots  encourage the  formation of
air pollutants such as hydrogen cyanide. The second
isothermal  configuration  was found controllable and
without  pollutants,  but owing  to  the  thermal
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decomposition  product mix,  the partially  oxidized
product  mix from  the  second  reactor was found
commercially unattractive.

   In   summation,   the   isothermal   reactor
configurations   were  found   to be   commercially
unattractive.  The   polystyrene   and  polyethylene
adiabatic reactors  were  found to be  commercially
feasible for energy production. Polyvinyl chloride and
the waste  plastic  adiabatic reactors  were found to
yield hydrogen chloride and heat.
            5. PRELIMINARY DESIGN
           AND ECONOMIC ANALYSES
   The  objective of this portion of the investigation
was  to  provide  information regarding the economic
potential  of proposed  chemical processes for waste
plastics  utilization.  The  analyses  were  based  on
preliminary process designs  accomplished by use of
chemical engineering principles together with material
and energy relationships supplied by reaction kinetic
analyses.

   Three  of  the  originally  proposed  coreactants
survived the screening and evaluation phase following
the  chemical  reaction  analyses. Specifically, those
coreactants were nitrogen, air (oxygen),  and water
(steam). The  results of the economic analyses for
waste plastic/nitrogen systems, wherein the  nitrogen
is   used   as  a  heat   carrier  for   the  thermal
decomposition   of   polystyrene,  polyethylene,
polyvinyl chloride, and a mixture of equal portions of
all  three,  are given  in what follows. In the next
section,  the  economic  analyses for the  four waste
plastic/air  (oxygen) systems are presented.  In those
analyses,  air was used as a  source of  oxygen for
combusting the selected waste plastics. Finally, the
economic analyses for the waste plastic/water (steam)
systems are discussed.  In  those cases, water,  rather
than nitrogen, was used as a source of heat for the
thermal degradation of waste plastics.
          Waste Plastic/Nitrogen Processes

   The   first  process  concept  analyzed   for  the
utilization  of waste plastics  involved using  hot
nitrogen to decompose thermally the selected waste
plastics  in  a  semicontinuous  moving-bed  reactor,
followed by  recovery  of the  reactor  effluent  and
separation  of the  useful products.  This  section
presents   the   results  of  economic   analyses
accomplished for proposed processes to decompose
polystyrene, polyethylene, polyvinyl chloride, and a
mixture of equal portions of all three. The economics
for  each   waste  plastics utilization  system  are
presented in what follows.

   Polystyrene/Nitrogen.  This first proposed process
for waste polystyrene utilization was  based on the
thermal  degradation  of  scrap polystyrene  to form
pure styrene monomer (Figure 34).

   The degradation is accomplished in a sfainless steel
reactor  at 600 C  in the presence of nitrogen, which is
used to  carry the heat required for the endothermic
styrene-producing reactions.  Nitrogen at 1,230 C  is
fed to the reactor through a number of inlets so that
the temperature  will  remain constant throughout. A
lower cost system might be based on the direct use of
burner   product   gases to provide  the  heat  and
eliminate the need for the gas-gas heat exchanger.
This configuration, however, was not considered for
the economic analyses, since the effect of the oxygen
carried  in  the heating gas would first have  to  be
determined. The  costs presented herein are therefore
probably higher   than  what  could  be  determined
following laboratory development.

   After leaving  the  reactor,  the  gaseous  reaction
products are cooled to 250 C by heat exchange with
the nitrogen recycle from the refrigeration step and
then sent to the secondary heat exchanger, where the
reaction products are further cooled with water to 50
C. Refrigeration  is used to cool the stream to 20 C,
removing all but  0.6 percent of the styrene monomer
from the gaseous nitrogen. The stream is then sent to
                                                    16

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a phase separator, and an inhibitor is added to the
liquid monomer before it  is pumped to the product
storage tank.

   The nitrogen leaving the refrigerator is recycled to
the direct  fired heater, cooling the effluent reactor
gases  on the  way. In the  direct fired  heater  step,
make-up nitrogen is  added to the  recycle nitrogen
stream (now at 460 C) and heated up to 1,230  C by
means of oil/gas combination burners.
   Overall capital and operating costs were estimated
 with the aid of computer subprograms written for the
 process as well as of modified existing subprograms.
 When the  installed  process equipment  costs  and
 hourly operating costs were summarized (Table 9) for
 a  plant designed to process 12.5 million Ib of scrap
 polystyrene per year, it was found that at current
 market values, the  plant  would  gross a  cost-price
 differential of  6.1  cents/lb  of  pure polystyrene
 processed. No estimate was made for potential waste
 plastic separation costs  although  a good part of the
 cost-price differential might be applied thereto.

   A  similar-  analysis  was  performed  with use  of
 nitrogen at 730 C to heat the polystyrene feed. It was
 found that  the  reduced  temperature necessitated
 increasing the  size  of  many pieces of the process
 equipment  by  a  factor of  five  with no increase in
 production. Increasing the size of pieces  of process
 equipment  would have  a detrimental effect on the
 process economics, and hence, the higher temperature
 was  used in  modeling  and costing  the  proposed
 process.

   Polyethylene/Nitrogen. The first proposed process
 for  waste polyethylene  utilization was  based on the
 thermal  degradation  of scrap  polyethylene to  form
 useful hydrocarbons (Figure 35).

   Nitrogen, used as an inert heat carrier, is preheated
 to 1,230  C  in  a direct  fired heater  using oil/gas
 combination burners. The hot nitrogen stream is  then
 fed  to the  semicontinuous stainless  steel reactor,
 where thermal degradation of the  polyethylene is
 accomplished at a  constant  temperature of 440 C.
 The reactions are only slightly endothermic, most of
 the heat carried by  the nitrogen being used to elevate
 the temperature of the polyethylene feed.

   After  leaving the  reactor, the  gaseous reaction
 products are cooled to 110 C by  heat exchange with
 cold  water  and then sent to the  secondary heat
 exchanger (condenser), where  the stream is further
 cooled to  45  C  (again  with cold water).   Phase
 separation is used to  separate the hydrocarbons that
 have  condensed from those that are still gaseous. Fuel
 credit was taken for the effluent  gaseous stream and
 gasoline  credit   was  taken   for   the   condensed
 hydrocarbon stream.

   Overall capital and  operating costs were estimated
 by use  of  computer  subprograms  written for  the
 polystyrene process  as well as of subprograms created
 specifically  for this process.  The  installed process
 equipment  cost  and  hourly  operating  costs  were
 summarized  (Table  10)  for  a  plant  designed   to
 process  12.5  million  Ib of scrap polyethylene  per
 year,  including contingencies and  contractor's fee.
 Even  with the credits  taken for all products and with
 the separation costs ignored, the process was found to
 be  uneconomical,  and  it  was concluded that  the
 process  should  be   compared   to  other  disposal
 techniques to determine its overall value.

   Polyvinyl Chloride/Nitrogen.  The first proposed
 process for  waste polyvinyl chloride utilization was
 based on the thermal  degradation of scrap polyvinyl
 chloride with  nitrogen to yield hydrogen chloride as
 the major product, hydrocarbon streams receiving
 fuel and gasoline credit (Figure 36).

   Nitrogen, used as  an inert heat carrier, is preheated
 to 1,230 C  in  a direct fired heater  using oil/gas
combination burners. The hot nitrogen stream is fed
to the semicontinuous stainless steel reactor, where
 thermal  degradation  of  the polyvinyl  chloride  is
accomplished at  a constant temperature  of 450 C.
The overall system is exothermic,  the heat carried by
the nitrogen being used to elevate  the temperature of
the polyvinyl chloride feed.
                                                   17

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   After leaving the reactor,  the gaseous reaction
products are sent to the scrubbing system, which is
capable of  removing  99  percent  of the hydrogen
chloride from  the reactor effluent.  •* The scrubber
process allows  recovery  of the hydrogen chloride
either  as acid,  at 18  Baume,  or, with the aid of a
simple  stripping  system, as  anhydrous hydrogen
chloride.

   The  installed process equipment cost  and hourly
operating  costs were summarized  (Table 11) for a
plant designed  to process 12.5  million  Ib of scrap
polyvinyl  chloride per  year, including contingencies
and contractor's fee. At current market values  there is
no gross cost-price differential for the processing of
pure  polyvinyl  chloride, and  this indicates  that
further information is  required for determining the
potential profitability of this process.

   Mixed  Waste  Plastics/Nitrogen.  This proposed
process involves  the  thermal  decomposition  of a
mixture   of   equal  portions  of  polystyrene,
polyethylene,  and  polyvinyl  chloride,  using  hot
nitrogen (Figure 37).

   Nitrogen,  again used as an inert heat carrier, is
preheated to 1,230  C in a direct fired heater using
oil/gas combination  burners. The hot nitrogen is fed
to the  semicontinuous stainless steel reactor, where
thermal degradation of the waste plastics mixture is
accomplished at a constant temperature of 600 C.

   After   leaving  the   reactor,  the   gaseous
decomposition products are cooled by heat exchange,
incoming  nitrogen  being sent to  the  direct  fired
heater for preheating. The stream temperature is then
lowered to   90 C with a water spray quench that
removes the hydrogen chloride and water from the
stream.  The  condensed  hydrogen  chloride/water
stream  is  sent to a phase separator for  recovery of
heavy  hydrocarbons for gasoline credit and then on
to a hydrogen chloride distillation column.

   The gaseous stream leaving the quench  is cooled to
50 C  with  a cold water  heat  exchanger, sent to a
phase  separator to remove fuel grade organics, and
then refrigerated to 20 C, which removes all but 0.6
percent of the styrene monomer from the gas stream.
The condensed styrene stream is further purified in a
vacuum finishing column, treated with an  inhibitor,
and sent to storage.

   When the  installed  process equipment costs and
hourly operating costs  for a plant designed to treat
12.5 million Ib of mixed waste plastics per year were
summarized   (Table  12), with  contingencies  and
contractor's fee included  in  the plant costs,  it was
found  that  the gross  cost-price  differential for the
mixed   plastic-heat  system  is   approximately  -0.1
cents/lb  of  plastics   processed,  credits  based  on
current market values being used. This again indicated
that further  research  is  required  for determining
profitability.

        Waste Plastic/Air (Oxygen) Processes

   The  second  method  studied for waste plastics
utilization  proposes   reacting  (combusting)  the
specified plastics with  oxygen (air).  Presented  in this
section are the results of analyses performed for the
four waste plastic/oxygen (air) systems. Specifically,
the  waste   plastics   treated  are  polystyrene,
polyethylene,  polyvinyl chloride, and a mixture  of
equal portions of all three. The economics for  each
system  of  waste  plastic disposal  will   now be
discussed.

   Polystyrene /Air and  Polyethylene/Air  Systems.
The proposed process for reacting polystyrene  or
polyethylene   with  air   is   based  on   controlled
combustion   of  the  plastic   in  an  air  (oxygen)
environment.   Once  combustion  is initiated,  the
reaction is  perpetuated by continuous  addition  of
plastic.

   Economic  analysis  of the   polystyrene/air  and
polyethylene/air  systems indicates  that   a   plant
designed  to  process  12.5  million  Ib  of   scrap
polystyrene or polyethylene per  year would yield
about  1.5 million Btu  of recoverable heat per hour.
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The process cost summary for either a polystyrene/air
or polyethylene/air system  (Table 13) indicates that
the relatively small amount of heat liberated by either
system  would  probably not justify the purchase of
process equipment to  make use  of it to  produce
steam. The alternative to steam production would be
to consider the polystyrene or polyethylene to be a
general  fuel, fit for burning as a source of heat with a
process value of $0.25 per million Btu. Contingencies
and contractor's fee  were  included in the  installed
boiler unit cost.

   Polyvinyl  Chloride/Air  and  Mixed Plastics/Air
Systems.  The   polyvinyl   chloride/air  and mixed
plastics/air systems  were considered together since
the combustion  products  of the two  systems are
nearly identical and require the  same process for
recovering usable process heat and valuable hydrogen
chloride.

   The  proposed  process   for reacting  polyvinyl
chloride or mixed plastics  with air  was based  on
controlled combustion  of the plastic in air  to yield
hydrogen  chloride (Figure 38).

   Air and chlorinated waste plastics are  fed to the
semicontinuous  stainless   steel  reactor,  where
combustion   is  accomplished   at  a   constant
temperature of 930 C  for the polyvinyl chloride/air
system and 1,600 C for the mixed plastics/air system.
Both systems are exothermic and self-perpetuating.

   From this point in the process, the steps  taken to
recover  the  hydrogen chloride are the same  as those
described  in the economic analysis of the process for
thermal  degradation of polyvinyl chloride.  After
leaving the reactor,  the gaseous reaction products are
sent to the  scrubbing system  which is  capable  of
removing  99  percent   of  the  hydrogen  chloride
contained in the  reactor effluent.   The scrubber
process  allows  recovery of the  hydrogen  chloride
either as  acid,  at 18  Baume, or, with the  aid of a
simple  stripping system,   as  anhydrous  hydrogen
chloride.
   The installed process  equipment  cost and hourly
 operating   costs,  including  contingencies  and
 contractor's fee, were  summarized (Table 14) for a
 plant  designed  to  process  yearly  12.5 million Ib  of
 scrap polyvinyl chloride or a blend of equal portions
 of polystyrene, polyethylene, and  polyvinyl chloride.
 The  gross  cost-price  differential  per  pound  of
 polyvinyl chloride reacted is 0.7 cents/(credit).

            Waste Plastic/Water Processes

   The third  coreactant  system investigated in this
analysis involves the use  of water (steam) as a heat
carrier  in  the  thermal  degradation of  the waste
plastics. The chemical reaction analyses for the waste
plastic/water  systems  without  catalysts  produced
results similar to those of the waste plastic/nitrogen
systems in that the distributions of reactor products
were  essentially  the same. Since water has a larger
heat capacity than  nitrogen has, the volume of steam
required in each system is significantly less than the
amount   of  nitrogen   required   for   the  waste
plastic/nitrogen  reaction  systems.  This  property  of
water  (steam) results in the  size reduction  of some
process equipment and  hence reduces  the overall
process  cost.  The results   of  economic  analyses
completed for each of the four waste plastic/water
coreactant systems  are now discussed.

   Polystyrene/Water.   This  process  proposes  the
direct  substitution  of water  (steam) for  nitrogen  in
the   polystyrene/nitrogen   process  (Figure   34).
Low-pressure  steam is fed to the  direct fired heater
(furnace), where its temperature is raised to 1,230  C.
The  steam is then  fed to  the reactor in  the same
manner as  nitrogen is fed in the polystyrene/nitrogen
process already described.

   With  the  steam for  nitrogen  substitution,  this
process is  analogous to the  rest  of the  process for
polystyrene/nitrogen.   The   installed   process
equipment cost and hourly operating costs for a plant
designed  to  process   12.5  million  Ib  of  waste
polystyrene   per   year   (1,580   Ib/hr),  including
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contingencies  and contractor's fee, were summarized
(Table  15).  The  gross cost-price  differential  was
found to be 6.1 cents/lb of feed.

   Polyethylene/Water.  The  proposed  process for
reacting  polyethylene with water again  involves the
substitution of steam for nitrogen (Figure  35).  The
remarks  in  the   previous  section concerning the
preparation of steam also  apply  here.  The process
costs were summarized (Table 16), and the byproduct
credits are reflected in  the cost-price  differential of
-0.6 cents/lb of feed.

   Polyvinyl   Chloride I Water,  The  substitution  of
steam for  nitrogen in  the  degradation  of  plastic  is
again  the essence  of this proposed process. Steam  is
preheated and sent to the reactor in the same manner
as described for the polystyrene/water system.

   Since the reaction  products for this process are
essentially  the  same   as  those for  the  polyvinyl
chloride/nitrogen  system  (Figure  36),  the reactor
effluent  is treated in exactly the  same manner. The
process  cost summary was seen to vary only slightly,
owing to the similarities of the two processes (Table
17).

   Mixed  Plastics/Water.   This  process   is   again
analogous  to its mixed plastics/nitrogen counterpart.
Low-pressure  steam is  sent  through the direct fired
heater (furnace) and heated to 1,230 C prior to being
sent to  the reactor. The reactor effluent would not be
first cooled by the incoming nitrogen, but the rest  of
the process is the same as the process to  decompose a
mixture  of waste  plastics with  hot  nitrogen,  as
already described (Figure 37). The economic analysis
indicated that the gross cost-price differential for this
proposed  process  would  be  0.3 cents/lb of  feed
(Table 18).

   6.  CONCLUSIONS AND RECOMMENDATIONS

   The  present study  has successfully demonstrated
the value of  computer-based simulation and analysis
of proposed chemical  processes. The information
resulting  from   the  analyses  provides  HEW
management with an evaluation of a large number of
chemical  process concepts  for the  use of  waste
plastics as  raw  materials  for  the production  of
commercially valuable  process chemicals. In addition
to these direct results, the project has also provided
information  applicable  to  other  related  process
techniques that might  be applied to waste disposal as
well as to the assessment of potential air pollution
problems  resulting  from the incineration of waste
plastic materials.

   The  chemical  process development technique was
used to analyze  18  separate concepts for the use of
various plastics as raw materials in the production of
commercially valuable  process chemicals. The various
stages  of  the analysis  have provided the information
required for narrowing the  concepts to those that
should be continued into the laboratory development
phase of the chemical  process development technique
as  follows:   polystyrene-thermal   decomposition,
polyvinyl  chloride-thermal  decomposition,  mixed
plastics-thermal   decomposition,   and  mixed
plastics-combustion   with   air.  The  individual
characteristics of the various systems to be examined
in  the  laboratory  development   phase are  now
presented.

   The  polystyrene-thermal  decomposition  system
 produces styrene by   using an inert  gas as a heat
 source. The particular information required from the
 laboratory  is related  to the design of  an  efficient
 reactor system  capable  of  volatilizing a maximum
 amount of the plastic materials. Process variables  to
 be examined include initial solid particle size, heating
 gas temperature-volume  tradeoffs,  heating gas duct
 locations,  reactor  design,  solid  residence  times,
 heating gas (the  direct use of combustion products in
 place   of nitrogen  or  steam  reduces  the  costs
 considerably),  and  separation  of styrene  from the
 heating gas.

   The  polyvinyl   chloride-thermal  decomposition
 system   produces   a   hydrocarbon   mixture  and
 hydrogen  chloride.  The  parameters to  be examined

-------
include those listed already, plus the identification of
reactor  conditions  leading  to a  more  desirable
hydrocarbon mixture. The separation of the various
components of the reactor effluent stream must also
be examined in detail.

   The  mixed plastic-thermal decomposition system
eliminates a major economic shortcoming of the first
two  separate processes in that it does  not require a
prereaction  separation  of the  plastic materials. The
laboratory development, however,  is more complex
since it would  require the examination of both  the
individual systems and the mixed system. The  depth
of the examination of the individual systems would
be less than that  required  for the first two. The
information described earlier would still be required
for  the  mixed  system, but  the  individual system
examinations would limit the regions examined.

   The mixed plastics combustion with air system is
essentially  a  chemical  processing  approach  to  a
commonly  used  waste  disposal   technique.  The
laboratory   development  would  be  primarily
concerned with the design  and testing of efficient
combusters  and with the separation of the effluent
hydrogen chloride  from  the combustion products.
This system is  of particular importance since it  has
been indicated  throughout the analysis that specific
measures are required to prevent hydrogen chloride
pollution resulting from the incineration of polyvinyl
chloride and other chlorinated organics.

   The  contract  effort provides, in addition  to  the
laboratory  development  recommendations  already
mentioned,   a   more  general  set   of  chemical
engineering  guidelines  applicable  to  the scope  of
research and development programs related to waste
disposal.  The  approach  used in  this  study  has
identified materials that appear to  have little or no
value   in   the   gas   phase   reaction  of
organic-chemical-based   waste  systems.  These
coreactants, hydrogen chloride and ammonia, should
be considered for further research and development
effort  only  where  specific  reaction  technology is
previously  known. It has further been demonstrated
that chlorine gas is  highly nonselective in  reactions
with mixed organic  systems  while, of course, it still
has great value in individual process systems. The lack
of selectivity greatly limits its value for using waste in
the production of marketable organic  chlorides. The
contract effort has  also indicated that future R&D
efforts relative to incineration should be concerned
both   with  the   design  of efficient  combustion
reactions  and  with the  recovery of valuable and
noxious  combustion  effluents  such  as  hydrogen
chloride  from chlorocarbons and hydrogen fluoride
from  fluorocarbons. Finally, the  economic analyses
have consistently indicated that labor is an important
cost factor in both the utilization and the disposal by
combustion of waste materials. The labor costs and
capital costs  per pound of product would be reduced
significantly  in large plant sizes. This indicates that
strong  consideration   should  be given   to   the
establishment  of a  network  of regional  waste
treatment plants not only for economic reasons but
also  for  prevention of  a  considerable   pollution
problem.
   The use of waste materials for the production of
process chemicals has demonstrated both economic
and technical feasibility under appropriate conditions
(partial or complete separation and large plant size).
Further  R&D efforts  in this  general  area  should
concentrate on the further examination of the waste
plastics systems that appear promising and  on  the
technical-economic  analysis  of concepts related to
other specific waste constituents  such as cellulosics.
Simultaneously,  concepts  involving  stage-by-stage
preprocessing and separation techniques should also
be examined.
                                                    21

-------

-------
                            7. REFERENCES
 1.  JANAF thermochemical tables. 3 v. (loose-leaf). Midland, Michigan, Dow
           Chemical  Company,  Dec.  31,  1960-Mar. 31,  1965.  Quarterly
           supplement. 1 v.  (loose-leaf). Sept. 30, 1962. First addendum. 1 v.
           (loose-leaf).  Aug. 1966. Second addendum. 1  v. (loose-leaf). Aug.
           1967.

 2.  Rossini, F. D., K. S. Pitzer, R. L. Arnett, R. M. Braun, and G. C. Pimentel.
           Selected values   of  physical  and  thermodynamic  properties of
           hydrocarbons and related compounds. Comprising the tables of the
           American Petroleum Institute Research Project 44, Extant as of Dec.
           31,  1952. Pittsburgh, Carnegie Press, 1953. 1050 p.

 3.  Gallant, R.  W. Physical properties of hydrocarbons. Part 6.  Chlorinated
           ethylenes. Hydrocarbon Processing, 45(6):153-160, June 1966.

 4.  Gallant, R.  W. Physical properties of hydrocarbons. Part 7.  Chlorinated
           aliphatics. Hydrocarbon Processing, 45(7):111-118, July  1966.

 5.  Gallant,  R. W.  Physical  properties  of hydrocarbons.  Part  8.  Primary
           alcohols. Hydrocarbon Processing, 45(10):171-182, Oct.  1966.

 6.  Gallant,  R.  W. Physical properties  of hydrocarbons. Part   10.  C3-C4
           alcohols. Hydrocarbon Processing, 46(1):183-189, Jan. 1967.

 7.  Gallant, R. W. Physical  properties of hydrocarbons. Part 11. Miscellaneous
           alcohols. Hydrocarbon Processing, 46(2):133-139, Feb. 1967.

 8.  Gallant, R. W. Physical properties of hydrocarbons. Part 12. C2-C4 oxides.
           Hydrocarbon Processing, 46(3):143-150, Mar. 1967.

 9.  Gallant, R.  W. Physical properties of hydrocarbons. Part 13. Ethylene
           glycols. Hydrocarbon Processing, 46(4): 183-196, Apr. 1967.

10.  Gallant, R.  W. Physical properties of hydrocarbons. Part 14. Propylene
           glycols and glycerine. Hydrocarbon Processing,  46(5):201-215, May
           1967.
                                   23

-------
11.   Gallant,  R. W. Physical properties of hydrocarbons. Part 19. Chlorinated
           C2's. Hydrocarbon Processing, 46(12):119-125, Dec. 1967.

12.  Gallant,  R. W.  Physical  properties of hydrocarbons. Part 24. C1-C4
           aldehydes. Hydrocarbon Processing, 47(5):151-160, May 1968.

13.  Lange, N. A.,  comp. and ed. Handbook of chemistry. 9th ed. Sandusky,
           Ohio, Handbook Publishers, Inc., 1956.  1969 p.

14.  Wagman, D. D., W. H. Evans, V. B. Parker, I. Halow, S. M. Baily, and R. H.
           Shumm.  Selected values  of chemical  thermodynamic properties.
           Tables for the first thirty-four elements in the standard order of
           arrangement.  U.S.  National  Bureau of Standards Technical Note
           270-3 (This Technical Note supersedes Technical Notes 270-1 and
           270-2). Washington, U.S. Government Printing Office, Jan. 1968.
           264 p.

15.  Benson,  S. W. Thermochemical kinetics. Methods for the estimation of
           thermochemical data and rate parameters.  New York, John Wiley
           and Sons, Inc., 1968. 223 p.

16.  Solving waste  problem profitably. Chemical  Week, 104(24):38-39, June
           14, 1969.

17.  Madorsky, S.  L.  Thermal degradation of organic polymers. New York,
           Interscience Publishers, 1964. 315 p. (Polymer Reviews, 7).

18.  Jellinek,  H. H. G. Degradation of vinyl polymers. New York,  Academic
           Press, Inc.,   1955.   329  p.  (Physical  chemistry.  A  series  of
           Monographs, III).

19.  Tsuchiya, Y., and K. Sumi. Thermal decomposition products of polyvinyl
           chloride. Journal of Applied Chemistry, 17(12):364-366, Dec. 1967.
                                    24

-------
                           8. BIBLIOGRAPHY

Bejuki, W. M. Degradation. In Encyclopedia of polymer science and technology.
     Plastics,  resins, rubbers, fibers, v. 4. New York, Interscience Publishers,
     1966. p. 647-725.

Benson, S.  W. The foundations of chemical kinetics. New York, McGraw-Hill
     Book  Company,  Inc., 1960.  703 p. (McGraw-Hill Series  in  Advanced
     Chemistry).

Boyd, R. H. Theoretical depolymerization kinetics in polymers having an initial
     "most probable"  molecular weight  distribution.  Journal  of Chemical
     Physics, 31(2):321-328, Aug. 1959.

Bush, R. W., T. Park, and  C. L. Kehr. Polymer oxidation process and emulsion
     therefrom. U.S. Patent 3, 322, 711, May 30, 1967.

Cameron, G.  G.  Mechanism  of volatile production  during  pyrolysis of
     polystyrene, Makromolekulare Chemie, 100:255-261, Jan. 13, 1967.

Cameron, G. G., and J. R. MacCallum. The thermal degradation of polystyrene.
     Journal of Macromolecular Science, Part C: Reviews in Marcomolecular
     Chemistry, Cl(2):327-359, 1967.

Flory,  P. J. Configurational statistics of chain molecules. In Proceedings; the
     Robert A, Welch Foundation  Conferences on  Chemical Research. X.
     Polymers, Houston, Nov. 21-23, 1966. p. 133-149; discussion, p. 149-166.

Geddes,  W.  C. Mechanism  of  PVC   degradation. Rubber Chemistry  and
     Technology, 40(1):177-216,  Feb. 1967.

Gilbert, J. B., J. J. Kipling, B. McEnaney, and J. N. Sherwood. Carbonization of
     polymers I-Thermogravimetric analysis. Polymer, 3:1-10, Mar. 1962.

Halstead,  M.  P.,  and  C. P.   Quinn.  Thermal  hydrogenation  of  ethylene.
     Transactions of the Faraday Society, 64(6):1560-1567, June 1968.

Hansel,  J. G., and R.  F.  McAlevy,  III. Energetics and chemical kinetics of
     polystyrene  surface  degradation  in  inert  and  chemically reactive
     environments.   AIAA   [American   Institute   of  Aeronautics   and
     Astronautics] Journal, 4(5):841-848, May 1966.

Houilleres du Bassin du Nord  et du Pas-de-Calais.  Process  for measuring the
     speed  of thermal decomposition of polymers. British  Patent 1,080,438,
     Aug. 23, 1967.
                                  25

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Imoto,   M.,   and   T.   Otsu.  Studies  on   polyvinylchloride.   III.  On
      dehydrochlorination  of polyvinylchloride  by  heating. Journal  of the
      Institute  of Polytechnics, Osaka City University, Series  C:  Chemistry,
      4(1):124-128, Apr. 1953.

Jellinek,  H.  H.  G. Degradation-termination reactions.  Journal  of Polymer
      Science, Part B: Polymer Letters, 2(4) =457-459, Apr. 1964.

Jellinek,  H. H.  G. Depolymerization. In Encyclopedia of polymer science and
      technology. Plastics, resins, rubbers, fibers, v.  4. New York, Interscience
      Publishers, 1966. p. 740-793.

Jellinek,  H.  H. G.  Photodegradation and  high temperature  degradation  of
      polymers. Pure and Applied Chemistry, 4(2):419-458, 1962.

Jenkins,  R. K., N. R. Byrd, and J. L. Lister. Chlorination of polystyrene. Journal
      of Applied Polymer Science, 12(9):2059-2066, Sept. 1968.

Joshi, R. M., and B. J. Zwolinski.  Heats of combustion  studies on polymers.
      Macromolecules,  1(1):25-30, Jan./Feb. 1968.

Joshi, R. M., B. J. Zwolinski, J.  M.  O'Reilly, and F.  E. Karasz. Configurational
      enthalpy of polystyrene. Journal of Polymer Science, Part A-2: Polymer
      Physics, 5(3):705-710, May 1967.

Joshi, R. M., B. J. Zwolinski,  and C. W.  Hayes. Correlation  procedures for
      estimating the enthalpies of vaporization,  formation, and polymerization
      and  certain  physical  properties of a-olefin polymers.  Macromolecules,
      l(l):30-36,Jan.-Feb. 1968.

Kerr, J.  A.,  and A. F. Trotman-Dickenson.  The reactors of alkyl  radicals. In
      Porter, G.,  and B. Stevens, eds. Progress in reaction kinetics, v.  1. New
      York, Pergamon Press, 1961. p. 105-127.

Knight, G. J. Thermal  degradation of polystyrene. Journal of Polymer Science,
      Part B: Polymer Letters, 5(9):855-857, Sept. 1967.

McAlevy,  R. F., Ill,  and J.  G. Hansel. Linear  pyrolysis of thermoplastics  in
      chemically  reactive  environments.   AIAA   [American  Institute   of
      Aeronautics and  Astronautics]  Journal, 3(2):244-249, Feb. 1965.

MacCallum,  J.  R.  The  mechanism  of  initiation  of  random  degradation.
      Makromolekulare Chemie, 99:282-286, 1966.
                                     26

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Madorsky, S. L. Rates of thermal degradation of organic polymers. SPE [Society
      of Plastics Engineers] Journal, 18(12):1482-1490, Dec. 1962.

 Mandelkern, L., A.  L. Allou, Jr., and M. Gopalan. The enthalpy  of fusion of
      linear polyethylene. Journal of Physical Chemistry, 72(1):309-318, Jan.
      1968.

Molera, M. J.,  and F. J. Stubbs. The kinetics of the thermal decomposition of
      olefins. Part II. Journal of the  Chemical Society, London, 381-391, 1952.

Petersen,  J., and B. Ranby.  Structure and properties of polyvinylchloride. 1.
      Molecular  structure  of chlorinated  PVC. Makromolekulare  Chemie,
      102:83-93, Mar. 1967.

Pinner,  S. H., ed. Weathering and  degradation of plastics. Based on a symposium
      at the Borough Polytechnic, London. New York, Gordon  and Breach,
      Science Publishers Inc.,  1966. 131 p.

Polymer  degradation  mechanisms.  Proceedings; U.S.  National  Bureau  of
      Standards   Semicentennial  Symposium   on   Polymer   Degradation
      Mechanisms, Washington, Sept. 24-26,  1951.  U.S.  National Bureau  of
      Standards Circular 525. Washington, U.S.  Government  Printing Office,
      Nov. 16, 1953. 280 p.

Rabinovitch, B. Regression rates  and the kinetics of polymer degradation.  In
      Tenth  Symposium  (International)   on  Combustion,   University   of
      Cambridge,  Cambridge, England,  Aug.  17-21,  1964.  Pittsburgh,  The
      Combustion Institute, 1965. p.  1395-1404.

Simha,  R., L.  A. Wall, and P. J.  Blatz. Depolymerization as a chain reaction.
      Journal of Polymer Science,  5(5):615-632, Oct. 1950.

Simha, R., and L. A. Wall. Some aspects of depolymerization kinetics. Journal of
      Polymer Science, 6(l):39-44, Jan. 1951.

Simha, R., L. A. Wall, and J.  Bram. High-speed computations in the kinetics of
      free-radical  degradation.  I.  Random initiation.  Journal  of  Chemical
      Physics, 29(4):894-904, Oct. 1958.

Smith, D. A.  Modification of a thermogravimetric balance for pyrolysis in a
      controlled atmosphere.  Rubber Chemistry and Technology, 37:934-935,
      1964.
                                    27

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Stull, D. R. Physical properties of styrene monomer. In Boundy, R. H., and R.
      F. Boyer,  eds. Styrene. Its polymers, copolymers and derivatives. New
      York,  Reinhold  Publishing  Corporation,  1952.  (American  Chemical
      Society Monograph Series), p. 47-82.

Talamini, G., and G. Pezzin. Kinetic study on the reaction of polyvinyl chloride
      thermal  dehydrochlorination.  Makromolekulare Chemie,  39(1-2):26-38,
      July 1960.

Valko, L. Kinetic study of thermal dehydrochlorination  of poly(vinyl chloride)
      in the presence of oxygen. Part II. Correlations of derived equations with
      experimental  results.  Journal  of Polymer  Science,  Part  C:  Polymer
      Symposia, No. 16(Part l):545-554, 1967.

Venn, R. G. A. Physical degradation of polyethylene due to  oxidation. Plastics
      Institute, Transactions and Journal, 35(118):601-605, Aug. 1967.

Vidotto, G.  A. Crosato-Arnaldi,  and G. Talamini. Determination of transfer to
      monomer in the vinyl chloride polymerization. Makromolekulare Chemie,
      114:217-225, May 1968.

Wall,  L. A., and J. H. Flynn. Degradation of polymers. Rubber Chemistry and
      Technology. 35:1157-1221, 1962.

Wall,  L. A. Polymer decomposition. Part 1. Thermodynamics, mechanisms, and
      energetics. Part 2. Energetics of polymer decompositions. SPE [Society of
      Plastics Engineers] Journal, 16(8):810-814, Aug. 1960; 16(9):1031-1035,
      Sept. 1960.

Wall,  L. A., S. Straus,  J.  H.  Flynn, D. Mclntyre,  and  R. Simha. The thermal
      degradation mechanisms of polystyrene. Journal of Physical  Chemistry,
      70(l):53-62, Jan. 1966.

Williams,  J.  L., and  K. J. Cleereman.  The  general  physical properties of
      polystyrene.  In  Boundy,  R. H., and R.  F.  Boyer,  eds. Styrene. Its
      polymers, copolymers  and derivatives. New York,  Reinhold Publishing
      Corporation,  1952.  (American  Chemical Society Monograph Series),  p.
      448-516.

Wunderlich, B., and C. M. Cormier. Heat of fusion of polyethylene. Journal of
      Polymer Science, Part A-2: Polymer Physics, 5(5):987-988, Sept.  1967.
                                     28

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-------
Initially
Considered
Thermochemical
Equilibrium
Results
Reaction
Kinetic
Results
Preliminary
Design and
Economi c
Results
                        Polystyrene
                    Polyethylene
       Polyvinyl Chloride
                        Hydrogen Chloride, Air, Chlorine, Ammonia, Water, Heat

                                     CHEMICAL SYSTEMS REMAINING
                        Polystyrene
                    Polyethylene
        Polyvinyl  Chloride
                              Air   Chlorine   Water   Heat
                        Polystyrene
                                     CHEMICAL SYSTEMS REMAINING
                    Polyethylene
        Polyvinyl  Chloride
                      Air



       System

Polyvinyl  chloride - Air

Polystyrene - Heat
Polyvinyl  Chloride - Heat
                                                   Heat
                                                (Steam or
                                                  Carrier)
         Product

       Heat - HC1

       Styrene monomer

       HC1  - Hydrocarbon
Recommended
For
Laboratory
Development
Mixed Plastics - Air
Polystyrene - Heat
Polyvinyl Chloride - Heat
Mixed Plastics - Heat
to give HC1  and Heat
to give Styrene
to give HC1  - Hydrocarbon Mixture
to give HC1,  Styrene and Hydrocarbons
            Figure 2.  Technical-economic analysis for plastic/coreactant
       chemical processes.  The analysis effort converges on those processes
       demonstrating both technical and economic feasibility for laboratory
       investigation.
                                         30

-------
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Final
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     Figure 3.  Project flow diagram.  Step-by-step diagram of the
approach applied to this study.
                               31

-------
                     Polyethylene
                     Polystyrene
                     Polyvinyl Chloride
 C,
 6 6
                                                              CH,
                                                              C6H6
                                                                ri^r
                                                                c.   DO
                                                              HC1
C6H6
                                                              C2H2
     Figure 4.  Thermal decomposition:  major products analysis.

species favored depend on the plastic's carbon-hydrogen ratio.
    Product
                                    32

-------
                    Polyethylene
           HC1
                                                            - HC1
Polystyrene
                    Polyvinyl Chloride
                                                              C6H6
                                                              CH,
                                                              HC1
C6H6
                                                                ^^ H,-
                                                                c.   bo
                                                              C2H2
                                                              HC1
                                        -C6H6
                                                                     £.r-
                                                                     00
                                                              C2H2
     Figure 5.  Hydrogen chloride:  major product analysis.  The addition
of hydrogen chloride to the plastics system does not lead  to the formation
of chlorinated addition products under the conditions examined.
                                    33

-------
                      Polyethylene
               NH.
Polystyrene
                      Polyvinyl  Chloride
                                                                 CH,
                                                                 C6H6
                                                                 CH,
                                                                 C6H6
                                                                 HC1
                                                                 CH
     Figure 6.  Ammonia:  major product analysis.  Ammonia is decomposed to
nitrogen and hydrogen under the equilibrium conditions examined.
                                     34

-------
              Polyethylene
     H20
Polystyrene
                                                               H,

                                                               CO
                                                              CO,
                                                              CO
                                                              CH
                                                              co
Polyvinyl  Chloride
                                                              HC1


                                                              H2
                                                              CH4

                                                              CO

                                                              COo
     Figure 7.  Water:  major product analysis.  Under the reaction
conditions examined, the major products of the reactions between the
plastics and water included no oxyorganic compounds.
                                   35

-------
                                                                 'CO
                       Polyethylene
            Air
Polystyrene
                       Polyvinyl Chloride
                                          'CO,
                                                                 >H2°



                                                                 'HCN
'CO




• CO,
  L




.Ho
                                                                 •HCN
                                                                 •HC1
                                                                 •CO
                                                                 -C0
                                                                 •HCN
     Figure  8.   Air:  major product analysis.  As was the case with

water, no  oxyorganfc compounds were favored under the conditions examined.
                                      36

-------
                   Polyethylene
           Cl.
Polystyrene
                    Polyvinyl  Chloride
                                                             HC1
                                                             CH,
                                                             C6H6
                                                              cci2cci2
                                                              HC1
                                                              C6H6
                                                              cci2cci2
                                                              CC1
     Figure 9.  Chlorine:  major product analysis.  Under the equilibrium
conditions examined, the plastics/chlorine systems favored the formation
of various chlorinated organic compounds.
                                   37

-------
J



LU
1—
oo
oo
u_
0
oc
LU
LU
LU
LU
DC
u_
LU
I — i
| —
_J
POLYSTYRENE POLYETHYLENE POLYVINYL C
-(CHCHo)- -(CH0CH0)- -(CHC1CH7)-
• z n 1 Z -n i^n
C6H5






CH3C6H5
trans CH3CHCHC6H5
cis CH3CHCHC6H5
OirtflO Liriotj^iH/ drlCjiio

•mc.4-f\ PU |° T4 PUPT4
iiic L d Vjn.o^/-n/ 'onL'n.r)
J Q t|. ^
„._„._ PTJ P 13 PTJ PT4
L/ciLcl V^ilnL//:!!/ LfilLirlo
i O A ^

Cl
pri ptr , upl
L«rl_L»rirt / nU-L
CH3CH2CH3 | C2H5C6H5
CH3C6H5
CU C1 U UP 1
on.[-L//-n[- rivfj.

ortho CH3C6H4CH3 CH3C6H5
meta CH3C6H4CH3 CHC1CC12
para CH3C6H4CH3 CC12CC12
( C6H6 ( CH4 ( C6H6
) CHoCHCcHc I Cf,R{. 1 HC1
LU
     Figure 10.  Feasible reaction path species, thermal decomposition,
773 K, 1 atm.  The compounds in the higher relative free-energy ranges
are found in significant quantities at equilibrium only when the lower
energy products are deleted from consideration.  (Polystyrene at
1,073 K in place of 773 K.)
                                   38

-------
I




SYSTEM
u_
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LU
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LU
LU
LU
Lu
LU
I — i
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t
_J
LU





















POLYSTYRENE POLYETHYLENE POLYVINYL CHLORIDE
-(CHCH2)- -(CH2CH2)- - CHCH2 -
CH2CHC6H5

CH3C6H5

CH4
CO
co2
C6H6

CH2CHCH3
CH3COCH3
CH3CHO
323
C2H5C6H5
CH0C.~Hr
Job
ortho CH3CgH4CH3
1
ortho CH3CgH4CH3
meta CH.,CgH4CH3
para CH3CgH4CH3
ortho CH3CgH4CHCH2
meta CnnC,-n.CHCHp
para CH3CgH4CHCH2
CH3CHO
HC1
~« 4. -, f*U C 14 PU
meia on.-)"/-n/ion->
JUT- J
para CH3CgH4CH3






CH4
CH3C6H5
CHpCrlC/-H|-
HC1
CO
co2
C6H6
H2

CO
co2
CH4
C6H6
wn
     Figure 11.  Feasible reaction path species, air, 773 K, 1 atm, 70
percent plastic material.  Deletion of the normal combustion products
from consideration leads to product distributions similar to those from
thermal decomposition.  Deletion of these compounds gives some oxyorganic
products.
                                     39

-------
POLYSTYRENE

-(CHCH2)F
POLYETHYLENE

—(CH2CH2)—
                                           POLYVINYL CHLORIDE
                                                Cl

' SYSTEM
u_
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>-
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C5H8
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C2H4
CH9CHCH9CHCH?
£_!-•-.
CHC12CHC12
CH3C6H5

CHpCHC/-Hr
C6H6
cci2cci2
HC1

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CHoCHo^n-
323
PU P U
CH3C6H5
(isomers) C9H9C'
C, L.
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o b o
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ortho CH3C6H4CH
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OUT1 %3
para CH3CgH4CH3
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CH,
H2
HC1

HC1
C6H6
cci2cci2
CHA
     Figure 12.   Feasible reaction path species,  chlorine,  773 K,  1 atm,
70 percent plastic material.   Many different chlorinated products  are
favored following the deletion of the lowest energy products.
                                   40

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       53

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  WASTE

  PLASTICS
                                                         PRODUCT

                                                         + 1SL
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                          UNREACTED WASTE PLASTIC
     Figure 26.  Semlcontinuous waste plastics reactor.  The dimensions

specific  to each of the plastic systems are given in Table 3.
                                54

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                    57

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PLASTICS
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      Figure 30.  Semicontinuous waste plastics reactor.  Thermal
 decomposition of mixed plastics system.
                                  58

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                                                   OXIDATION PRODUCTS
                                                   TO A HEAT EXCHANGER
WASTE
PLASTICS
                                                          AIR
              Figure 33.  Waste plastic combustion reactor.  Solid plastics are
         burned with air for the production of heat energy.
                                        61

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                     TABLE 1

POLYETHYLENE THERMAL DECOMPOSITION  (710 K REACTOR
TEMPERATURE, 3,000-sec RESIDENCE TIME, 1.0  g/sec
POLYETHYLENE FEED)
COMPONENT
C2H4
C2H6
C3H4
C3H6
C3H8
C4H8
C4H10
C5H8
C5Hi0
C5Hl2
C6H10
C6H12
C6Hl4
C7H14
C7Hi6
j'1N2 ~ 1'500
N2 } T = 1,000 K
(10+2) g/sec
1.8
5.5
0.15
3.25
9.60
19.90
15.85
0.35
7.65
6.40
0.40
3.95
1.65
0.30
0.60
191.00
520.40
  Unreacted polyethylene
22.65
                         67

-------
                     TABLE 2

POLYVINYL CHLORIDE THERMAL DECOMPOSITION  (723 K REACTOR
TEMPERATURE, 255-sec RESIDENCE TIME, 1 g/sec POLYVINYL
CHLORIDE)
COMPONENT
HC1
C2H4
C2H6
C3H6
C3H8
C4Hg
C4H10
C5H10
C5Hl2
C6H6
C6H12
C6H14
C7Hg
C8H8
C2H4C12
H2
CH4
fT = 1,500 K
3 2
N2 )
IT = 1,000 K
V 2
Unreacted polyvinyl chloride
(10+2) g/sec
51.00
7.18
3.71
1.28
1.97
4.16
2.12
3.63
1.13
5.67
0.83
0.91
3.02
1.29
1.44
0.23
1.44
127.62
344.90
9.00
                          68

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                                        69

-------
                     TABLE 4

         NITROGEN EFFECT ON STYRENE-CHLORINE

REACTION-SECOND REACTOR  (900 K REACTOR TEMPERATURE,
1.25 atme, 0.68 g/sec CHLORINE FEED, 1.00 g/sec
STYRENE FEED, 25 sec RESIDENCE TIME)
Species
C12
HC1
0 g/sec N2
(g/sec)
0.023
0.098
1.66 g/sec
(g/sec)
0.211
0.073
N2


               CH=CH,
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                               0.207
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                           70

-------
                    TABLE 5




        AMOUNT OF INDICATED HEAT SOURCE*




      NECESSARY FOR THE SPECIFIED CONVERSION

Polystyrene,
Converted


823 K
(%) 55
50
25
Nitrogen
(g)
9.35
9.13
7.96
Steam
(g)
4.47
4.38
3.82
Polyvinyl Chloride, 673 K
Converted

Polyethylene
ADP 822
Converted
(%) 90
75
50
, 685 K
(%) 75
50
1.14
1.04
1.00

1.75
1.51
0.58
0.55
0.53

0.86
0.74
* 1,500 K heat source temperature, 1 g plastic.
                          71

-------
                     TABLE 6

MIXTURE REACTION PRODUCTS AT 700 K AND  4,400  sec  SOLID
RESIDENCE TIME.  BASIS:  1 g OF MIXTURE, WITH EQUAL
PARTS (BY WEIGHT) OF POLYVINYL CHLORIDE, POLYETHYLENE,
AND POLYSTYRENE.
Product
CH4
C2H4
C2H6
C3H4
C3H6
C3H8
C4H8
C4H10
C5H8
C5H10
C5H12
g (xlO3)
1.00
32.73
31.35
0.49
14.99
37.79
78.68
58.39
1.22
37.96
24.77
Polyvinyl chloride 14.56
Polystyrene 298.52
Polyethylene 88.17
Product
C.H
6 6
C6H10
C6H12
C6H14
C7H8
C7H14
C7H16
C8H8
C2HC12
H2
HC1
Steam (1,500
g (xlO3)
21.40
1.23
15.64
8.71
11.42
0.98
1.96
39.47
5.52
0.99
175.92
K)
                                  Required 1045.30
                           72

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-------
                          TABLE 8




            WASTE PLASTICS/AIR ADIABATIC REACTOR*
Mixture (Equal
Products Polyvinyl Parts by Weight
(g) Chloride Polyethylene Polystyrene of the three)
C02 1.41 3.06
CO traces 0.06
H20 0.30 1.27
N2 12.00 13.19
NO traces 0.06
02 2.12 0.34
HC1 0.55
C12 0.04
Others traces 0.02
Temperature
out of 1,200 K 2,130 K
reactor
Weight of
Air input 15.40 16.99
3.19 2.69
0.08 < 0.01
0.66 0.77
11.74 12.85
0.06 0.05
0.34 0.01
0.18
traces
0.02 0.01
2,200 K 1,870 K

15.10 16.55
* All data based on 1 g of plastic.
                               74

-------
                   TABLE 9
PROCESS COST SUMMARY.  POLYSTYRENE DECOMPOSITION
WITH NITROGEN AS A HEAT CARRIER.  INSTALLED UNIT
COST:  $219,000
                   Summary        $/hr


Utilities                        0.90

Raw materials                    1.40

Labor with 100% overhead         9.50

Depreciation, maintenance,
 taxes, etc.  (20% of
 capital annually)               5.50

                       Total    17.30

Waste polystyrene-processing     1.1   C/lb feed
 cost

Product credit:
 styrene                         7.2   £/lb feed

Net credit                       6.1   C/lb feed
                       75

-------
                  TABLE 10

PROCESS COST SUMMARY:  POLYETHYLENE DECOMPOSITION
WITH NITROGEN AS A HEAT CARRIER.  INSTALLED UNIT
COST:  $199,000
           Summary               $/hr


Utilities                        1.50

Raw materials                    5.30

Labor with 100% overhead         9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)               5.05

                       Total    21.35

Waste polyethylene-
 processing cost                 1.8    C/lb feed

Product credits:
 Gasoline stream and
 fuel gas                        0.5    £/lb feed

Net expense                      1.3    C/lb feed
                       76

-------
                  TABLE 11

PROCESS COST SUMMARY:  POLYVINYL CHLORIDE
DECOMPOSITION WITH NITROGEN AS A HEAT SOURCE.
INSTALLATION UNIT COST:  $464,000.
        Summary                  $/hr


Utilities                         7.80

Raw materials                    19.70

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)               11 70

                       Total     48.70

Waste polyvinyl chloride-
 processing cost                  3.1  C/lb feed

Product credits:
 organic stream and HCl acid      3.1  £/lb feed

Net expense                       0    C/lb feed
                         77

-------
                   TABLE 12

PROCESS COST SUMMARY:  MIXED PLASTICS DECOMPOSITION
WITH NITROGEN AS A HEAT CARRIER.  INSTALLED UNIT
COST:  $307,000
       Summary                   $/hr


Utilities                         3.35

Raw materials                     7.90

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)                7.75

                       Total     28.50

Waste mixed plastics-
 processing cost                  1.8  £/lb feed

Product credits:
 styrene, HCl acid, gasoline
 stream                           1.7  C/lb feed

New expense                       0.1  £/lb feed
                        78

-------
                   TABLE 13

PROCESS COST SUMMARY:  COMBUSTION WITH AIR OF
POLYSTYRENE OR POLYETHYLENE WASTE.  INSTALLED
BOILER UNIT:  $13,000
          Summary                $/hr


Utilities*                       (0.40)

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.  (20% of
 capital annually)                0.35

                       Total      9.45

Waste polystyrene or
 polyethylene disposal cost       0.6  £/lb feed
*Includes credit for process heat generated.
                       79

-------
                  TABLE 14

PROCESS COST SUMMARY:  COMBUSTION WITH AIR OF
POLYVINYL CHLORIDE OR MIXED PLASTICS SYSTEM.
INSTALLED PLANT COST:  $395,000.
          Summary
$/hr
Utilities and raw materials

Labor with 100% overhead

Depreciation, maintenance,
 taxes, etc. (20% of
 capital annually)
Chlorinated plastic-
 processing cost

Product credit:
 hydrochloric acid

Net credit
                       Total
18.00

 9.50



 9.85

37.35


 2.4   C/lb feed


 3.1   C/lb PVC feed

 0.7   C/lb feed*
*Calculated on the basis of pure PVC feed.
                            80

-------
                  TABLE 15

PROCESS COST SUMMARY:  POLYSTYRENE DECOMPOSITION
WITH STEAM AS A HEAT CARRIER.  INSTALLED UNIT
COST $183,000.
         Summary                 $/hr


Utilities                         2.20

Raw materials                     1.40

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.  (20% of
 capital annually)                4.60

                       Total     17.70

Waste polystyrene-processing
 cost                             1.1    C/lb  feed

Product credit:
 styrene                          7.2    <=/lb  feed

Net credit                        6.1    C/lb  feed
                        81

-------
                 TABLE 16

PROCESS COST SUMMARY:  POLYETHYLENE DECOMPOSITION
WITH STEAM AS A HEAT CARRIER.  INSTALLED UNIT
COST $151,000.
         Summary                 $/hr


Utilities                         2.50

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)                3.80

                       Total     15.80

Waste polyethylene-processing
 cost                             1.0   «/lb feed

Product credits:
 gasoline stream and fuel
 gas                              0.4   £/lb feed

Net expense                       0.6   £/lb feed
                        82

-------
                  TABLE 17

PROCESS COST SUMMARY:  POLYVINYL CHLORIDE
DECOMPOSITION WITH STEAM AS A HEAT CARRIER.
INSTALLED UNIT COST:  $436,000.
            Summary              $/hr


Utilities                         7.80

Raw materials                     7.20

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)               11. 00

                       Total     35.50

Waste polyvinyl chloride-
 processing cost                  2.3   C/lb feed

Product credits:
 organic stream and HC1
 acid                             3.1   C/lb feed

Net credit                        0.8   $/lb feed
                         83

-------
                  TABLE 18

PROCESS COST SUMMARY:  MIXED PLASTICS
DECOMPOSITION WITH STEAM AS A HEAT CARRIER.
INSTALLED UNIT COST:  $282,000.
        Summary                  $/hr


Utilities                         3.65

Raw materials                     1.40

Labor with 100% overhead          9.50

Depreciation, maintenance,
 taxes, etc.   (20% of
 capital annually)                7.15

                       Total     21.70

Waste plastic disposal cost       1.4    <=/lb

Product credits:
 styrene                          0.3
 HC1  (18 B)                       1.0
 gasoline stream                  0.4

                       Total      1.7    £/lb  feed

Waste plastic-processing cost     1.4    C/lb  feed

Product credits:
 styrene, HCl acid, gasoline
 stream                           1.7    C/lb  feed

Net- credit                        0.3    C/lb  feed
                       84

-------
                             APPENDIX A

                EQUILIBRIUM PRODUCT DISTRIBUTION

   The  quantities presented  in this  appendix represent the results  of the
equilibrium product distributions and analyses described in chapter 3. The values
tabulated are the moles of each  particular product per unit monomer of plastic.
The  values are presented as a  function of temperature, pressure, and initial
composition (weight percent polymer in the reacting system).

   The  tabular form used  is convenient  for the  preparation of plots,  as is
illustrated in  Figure 39, where methane production is presented as a function of
temperature for the  polyethylene  decomposition.  The data format used in the
tables is an exponential form, i.e., X.XX-Y is equivalent to X.XXX * 10~\  Zero
indicates a number of moles less than 1  *  10" . A complete list of the species
considered in the equilibrium analysis is included in this appendix.
                                   85

-------
86

-------
                         TABLE  19

POLYETHYLENE DECOMPOSITION.  COMPOSITION AS  A FUNCTION OF
TEMPERATURE, PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W





100






T (C) psia
2,400 1,000
14.7
2,000 1,000
14.7
1,600 1,000
14.7
1,200 1.000
14.7
800 1,000
14.7
500 1,000
14.7
C6H6
0
0
0
0
0
0
1.90-1
2.62-1
1.66-1
2.32-1
1.29-1
2.04-1
C2H4
1.19-2
1.64-4
4.44-2
7.88-4
1.62-1
6.32-3
2.08-2
1.73-2
1.83-2
2.88-3
0
0
CH4
1.95-2
2.86-4
8.01-2
1.50-3
2.86-1
1.45-2
4.84-1
1.56-1
6.72-1
5.32-1
6.27-1
6.51-1
CH2CH
C6H5
9.53-1
1.01
8.29-1
9.97-1
4.06-1
9.70-1
9.70-1
7.44-1
3.22-2
1.92-1
1.85-3
1.20-2
                            87

-------
                         TABLE  20

POLYETHYLENE/NH3 COMPOSITION AS A FUNCTION  OF  TEMPERATURE,
    PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W T (C) psia
1,200 1,
14
70 800 1,
14
500 1,
14
1,200 1,
14
50 800 1,
14
500 1,
14
1,200 1,
000
.696
000
.696
000
.696
000
.696
000
.696
000
.696
000
14.696
20 800 1,
000
14.696
500 1,
000
14.696
CH
9.
2.
1.
1.
1.
1.
1.
4.
1.
1.
1.
1.
1,
9,
2.
2.
2.
2.
4
81-1
90-1
30
07
34
35
57
42-1
98
71
99
99
99
63-1
01
01
01
,01
C6H6
1.23-1
2.08-1
8.65-2
1.46-1
6.53-2
9.95-2
3.93-2
1.56-1
0
4.29-2
0
0
0
2.58-2
0
0
0
0
H2
5.
1.
7.
4.
4.
2.
1.
2.
4.

05-
59
91-
45-

1

2
1
65-3
92-
03
75
69-
2


1
8.87-1
4.
4.
7.
9.
7.
7.
6.
7.
36-1
69-1
93
44
80
91
90
,90






                             88

-------
                          TABLE 21

POLYETHYLENE/HoO COMPOSITION AS A FUNCTION OF TEMPERATURE,
             PRESSURE,  AND INITIAL COMPOSITION
Percent
polymer
W/W T (C)
1,200

70 800

500

1,200

800
50
500

1,200

800
20
500

psia
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
CH4
9.16-1
2.57-1
1.24-1
9.95-1
1.22
1.29-1
5.09
2.63-1
1.19
4.69-1
1.47
1.30
9.63-3
0
7.32-1
2.24-3
1.40
8.24
CO
6.64-1
6.65-1
6.18-1
6.65-1
1.33-1
5.70-1
1.46
1.55
4.82
1.51
1.62-2
1.72-1
1.50
1.50
4.67-1
1.14
9.95-3
1.31-1
co2
3.61-4
0
2.25-2
0
2.66-1
4.80-2
2.46-2
0
3.15-1
1.03-2
5.07-1
5.18-1
5.06-1
5.05-1
8.09-1
8.64-1
6.02-1
1.05
H2
5.76-1
1.59-1
8.43-2
4.96-1
4.50-3
3.63-2
2.46
2.91
7.25-1
2.59
8.62-2
5.91-1
4.49
4.52
2.62
4.88
4.31-1
2.59
                                  89

-------
                         TABLE 22

POLYETHYLENE/AIR COMPOSITION AS A FUNCTION OF TEMPERATURE,
              PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W T (C) psia CH4 CO C02 H2

HCN
          1,200   1,000   5.04-1  1.75-1  0       2.83-1  1.93-2

                  14.696  1.43-1  1.74-1  0       8.51-1  8.36-2

            800   1,000   6.74-1  1.72-1  1.24-3  4.28-2  5.07-4

70                14.696  5.55-1  1.74-1  0       2.44-1  2.24-3

            500   1,000   6.75    6.61-2  5.41-2  2.37-3  0

                  14.696  7.07-1  1.69-1  2.84-3  1.59-2  0


          1,200   1,000   5.33-1  4.06-1  0       3.58-1  3.24

                  14.696  1.34-1  4.06-1  0       9.83-1  1.40-1

            800   1,000   7.45-1  3.97-1  4.62-3  5.66-2  8.47-4

50                14.696  5.89-1  4.08-1  0       3.11-1  3.74-3

            500   1,000   7.28-1  1.27-1  1.39-1  3.00-3  0

                  14.696  7.79-1  3.85-1  1.05-2  2.09-2  0


          1,200   1,000   3.54-1  1.62    3.43-3  6.62-3  -1.83-2

                  14.696  7.64-2  1.64    0       0       1.79-1

            800   1,000   7.32-1  1.01    2.61-1  1.04-1  0

20                14.696  3.70-1  1.64    1.90-3  1.35-3  1.62-3

            500   1,000   9.89-1  3.21-1  6.59-1  3.14-3  0

                  14.696  8.78-1  6.53-1  4.77-1  3.17-2  0
                               90

-------
                          TABLE 23
POLYETHYLENE/C12  COMPOSITION AS A FUNCTION OF  TEMPERATURE,
              PRESSURE,  AND INITIAL COMPOSITION
Percent
polymer
W/W

70




50




20



T (C) psia
1,200 1,000
14.696
800 1,000
14.696
500 1,000
14.696
1,200 1,000
14.696
800 1,000
14.696
500 1,000
14.696
1,200 1,000
14.696
800 1,000
14.696
500 1,000
14.696
CH4
3.84-1
1.14-1
5.08-1
4.26-1
5.16-1
4.77-1
2.61-1
6.76-2
3.63-1
2.93-1
3.69-1
3.89-1
C H
2 6
2.77-1
1.14-1
2.64-1
2.68-1
2.69-1
2.69-1
C6H6
2.09-1
2.67-1
1.87-1
2.50-1
1.50-1
2.23-1
2.34-1
2.72-1
2.16-1
2.72-1
1.80-1
2.50-1
CC1 CC1
2 2
0
0
1.87-1
1.90-1
1.82-1
1.90-1
HC1
3.37-1
3.38-1
3.37-1
3.38-1
3.37-1
3.38-1
7.86-1
7.88-1
7.86-1
7.87-1
7.86-1
7.89-1
HC1
2.21
3.06
2.39
2.39
2.39
2.39
                                 91

-------
                         TABLE 24

POLYSTYRENE DECOMPOSITION, COMPOSITION  AS  A FUNCTION OF
  TEMPERATURE, PRESSURE, AND INITIAL  COMPOSITION
Percent
polymer
W/W


100



T(C)
1,200

800

500

psia
1,000
14.7
1,000
14.7
1,000

C2H2
8.98-3
1.62-1
0
3.36-4
0

C6H6
1.19
1.25
1.29
1.32
1.33

C"^ H f\ CHC*/-
1.03-1
2.59-2
3.10-2
7.81-3
5.18-3

H5





                                92

-------
                         TABLE 25

POLYSTYRENE/NH3 COMPOSITION AS A FUNCTION  OF  TEMPERATURE,
             PRESSURE, AND INITIAL  COMPOSITION
Percent
polymer
W/W


70





50





20



T (C) psia
1,200 1,000
14.7
800 1,000
14.7
500 1,000
14.7
1,200 1,000
14.7
800 1,000
14.7
500 1,000
14.7
1,200 1,000
14.7
800 1,000
14.7
500 1,000
14.7
CH4
1.85
5.43-1
2.44
2.04
2.49
2.57
4.27
1.19
5.78
4.67
6.03
6.01
7.96
3.48
8.08
8.08
8.09
8.08
C6H6
7.88-1
1.00-1
7.02
9.48-1
5.58-1
8.37-1
4.41-1
7.68-1
2.79-1
5.26-1
2.06-1
3.07-1
0
1.59-1
0
0
0
0
H2
9.82-1
3.05
1.46-1
8.49-1
8.44-3
5.46-2
2.51
7.25
3.92-1
2.14
2.32-2
1.45-1
2.50+1
3.17+1
2.46+1
2.50+1
2.18+1
2.49+1
                             93

-------
                         TABLE 26

POLYSTYRENE/H20 COMPOSITION AS A FUNCTION OF TEMPERATURE,
             PRESSURE, AND  INITIAL COMPOSITION
Percent
polymer
W/W T (C) psia
1,200 1,
14
70 800 1,
14
500 1,
1,200 1,
14
50 800 1,
14
500 1,
14
1,200 1,
14
20 800 1,
14
500 1,
000
.7
000
.7
000
000
.7
000
.7
000
.7
000
.7
000
.7
000
14.7
CH
1.
4.
2.
1.
2.
2.
8.
3.
2.
4.
4.
2.
0
2.
7.
4.
2.
4
70
67-1
30
87
05
27
25-1
94-1
24
84
43
88-2

47
13-3
71
84
CO
2.
2.
2.
2.
5.
5.
5.
2.
5.
5.
1.
5.
5.
1.
4.
4.
5.
co2
48
49
36
48
21-1
68
78
85
74
20-1
54
87
89
98
46
97-2
39-1
1
0
€
0
9
2
0
1
1
2
2
2
2
3
3
3
4
.25-3

.18

.82-1
.48-2

.20
.53-2
.62
.02
.20
.19
.64
.61
.32
.68
H2
1
2
1
8
7
5
7
1
5
3
7
1
1
8
1
1
8
.03
.97
.57-1
.92-1
.25-3
.16
.38
.36
.28
.45-2
.34-1
.42+1
.43+1
.38
.57+1
.29
.28
                                   94

-------









































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95

-------
                       TABLE  28

POLYSTYRENE/C12 COMPOSITION AS A FUNCTION OF TEMPERATURE,
             PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W T (C)
1,200

70 800

500

1,200

50 800

500

1,200

20 800

500

psia
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
1,000
14.7
cci4
2.18-1
1.34-4
2.75-4
0
2.56-3
4.42-4
5.46-1
2.13-3
8.61-4
1.69-4
7.04-3
1.40-3
2.25-1
6.94-1
5.22-3
1.02-3
4.22-2
8.42-3
C6H6
1.16
1.25
1.24
1.26
1.26
1.26
1.12
7.45-1
1.14
1.17
1.16
1.17
8.81-1
2.82-3
6.70-1
6.83-1
6.84-1
6.83-1
CC12CC12
0
0
2.07-1
2.07-1
2.05-1
2.07-1
0
0
4.78-1
4.84-1
4.72-1
4.84-1
0
0
1.94
1.96
1.90
1.96
HC1
3.20-1
1.25
4.19-1
4.19-1
4.17-1
4.19-1
5.94-1
2.88
9.69-1
9.79-1
9.63-1
9.79
2.26
7.87
3.94
3.95
3.89
3.94
                              96

-------
                          TABLE 29

SYSTEM:  POLYVINYL CHLORIDE DECOMPOSITION, COMPOSITION AS
A FUNCTION OF TEMPERATURE, PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W       T (C)    psia   C2H2     C2H6     CH2CHCH5   HC1
          1,200    1,000  5.82-3   3.08-1   1.69-2     9.98-1

                   14.7   9.88-2   2.95-1   3.84-3     1.00


100         800    1,000  0        3.25-1   4.90-3     1.00-0

                   14.7   2.12-4   3.31-1   1.23-3     9.98-1


            500    1,000  0        3.31-1   8.13-4     9.98-1

                   14.7   0        3.33-1   2.01-4     9,98-1
                               97

-------
                      TABLE 30

SYSTEM:  POLYVINYL CHLORIDE/NH3.  EQUILIBRIUM COMPOSITION AS
A FUNCTION OF TEMPERATURE, PRESSURE, AND  INITIAL COMPOSITION
             (moles products/unit monomer)
Percent
polymer
W/W


70





50





20



T (C)
1,200

800

500

1,200

800

500

1,200

800

500

psia
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
CH4
1.052
2.691-1
1.443
1.154
1.553-1
1.541
1.911
5.735-1
1.999
1.985
2.000
2.000
1.982
1.172
2.000
1.999
2.000
2.000
H2
7.207-1
1.929
1.974-1
6.201-1
7.002-3
4.378-2
2.602
4.600
2.478
2.507
2.251
2.500
1.899+1
2.023+1
1.874+1
1.902+1
1.650+1
1.897+1
HC1
9.983-1
9.996-1
9.989-1
9.999-1
9.995-1
9.997-1
9.995-1
9.998-1
1.000
9.964-1
1.000
9.999-1
9.997-1
1.000
9.999-1
9.999-1
9.998-1
1.000
                             98

-------
                      TABLE  31

POLYVINYL CHLORIDE/H20 COMPOSITION AS  A FUNCTION OF TEMPERATURE,
             PRESSURE, AND INITIAL COMPOSITION
Percent
polymer
W/W


70





50





20



T (C)
1,200

800

500

1,200

800

500

1,200

800

500

psia
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
CH4
5.211-1
1.80-1
9.469-1
5.179-1
1.219
1.084
2.317-2
0
7.630-1
6.826-3
1.197
8.820-1
0
0
1.998-1
0
1.046
2.409-1
CO
1.465
1.486
7.60-1
1.478-1
9.448-2
4.702-1
1.710
1.738
5.569-1
1.516
1.576-2
1.701-1
9.569-1
9.574-1
4.382-1
5.606-1
1.218-2
1.185-1
H2
1.424
1.946
4.404-1
1.447
1.834-2
2.569-1
3.197
3.262
1.389
3.457
1.949-1
1.302
4.042
4.042
3.763
4.438-1
8.020-1
3.917
H20
1.158-2
0
1.502-1
2.643-3
2.563-2
6.206-2
1.226
1.208
1.553
9.982-1
1.879
1.403
1.083+1
1.083+1
1.072+1
1.044+1
1.198+1
1.048+1
HC1
9.996
9.998-1
9.996-1
9.997-1
9.996-1
1.000
9.998-1
1.000
1.000
9.997-1
1.000
1.000
9.999-1
9.999-1
1.000
9.999-1
9.999-1
1.000
                               99

-------
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                                                              100

-------
                         TABLE  33

POLYVINYL CHLORIDE/C12 COMPOSITION AS  A FUNCTION OF TEMPERATURE,
                PRESSURE, AND INITIAL  COMPOSITION
Percent
polymer
W/W


70





50





20



T (C)
1,200

800

500

1,200

800

500

1,200

800

500

psia
1,000
14.696

14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
1,000
14.696
CC14
1.31-1
2.02-3

0
3.50-3
7.34-4
3.18-1
1.81-2
1.01-3
0
8.18-3
1.63-3
1.32
1.01
4.32-1
1.95-1
5.24-1
5.18-1
C6H6
2.86-1
1.75-1

2.90-1
2.90-1
2.91-1
2.56-1
4.13-2
2.30-1
2.34-1
2.34-1
2.35-1
9.13-2
0
0
0
0
0
CC12CC12
0
0

1.23-1
1.18-1
1.25-1
0
0
2.84-1
2.88-1
2.78-1
2.88-1
0
0
7.83-1
9.02-1
7.33-1
7.40-1
HC1
1.13
1.71

1.25
1.25
1.25
1.32
2.57
1.58
1.58
1.58
1.58
2.32
2.97
3.00
3.00
2.99
3.00
                              101

-------
       SPECIES CONSIDERED IN EQUILIBRIUM ANALYSIS
carbon
graphite
carbon charged +1
carbon charged +2
carbon charged -1
diatomic carbon charged +1
diatomic carbon charged -1
methyl ion +1
carbon monoxide charged +1
carbon dioxide charged +1
carbon dioxide charged -1
cyanide ion -1
carbon hydroxide ion +1
diatomic carbon
(C3) carbon, trimeric
(C4) carbon, tetratomic
(C5) carbon pentatomic
CCH radical
methylidyne
methylene
methyl
ethylene
acetylene
methane
ethylene oxide
carbon monoxide
carbon dioxide
CCO radical
carbon suboxide
cyano  (CN)
CNN radical
NCN radical
cyanogen
carbon subnitride
carbon monochloride
carbon dichloride
carbon trichloride
carbon tetrachloride
CHC13
CH2C12
CH3C1
carbonyl monochloride
carbonyl chloride
ethane
propane
N-butane
N-pentane
N-heyane
iso-butane
isopentane
neo-pentane
                         102

-------
 2-methyl-pentane
 3-methyl-pentane
 2,2-dimethyl butane
 2,3-dimethyl butane
 cycle pentane
 methyl cyclopentane
 ethyl cyclopentane
 cyclohexane
 methyl cyclohexane
 ethyl cyclohexane
 propylene
 1-butene
 2-butene (cis)
 2-butene (trans)
 1-pentane
 2-penene (cis)
 2-pentene (trans)
 2-methyl, 1-butene
 3-methyl, 1-butene
 2-methyl, 2-butene
 propadiene
 1,  2-butadiene
 1,  3-butadiene
 cyclopentane
 cyclohexene
 propyne
 1-butyne
 2-butyne
 1-pentyne
 2-pentyne
 3-methyl, 1-butene
 benzene
 methyl benzene
 ethyl benzene
 1,  2-dimethyl benzene
 1,  3-dimethyl benzene
 1,  4-dimethyl benzene
 phenyl ethene
 cis-1-phenyl, 1-propene
 trans-1-phenyl, 1-propene
 (2-methyl phenyl)  ethene
 (3-methyl phenyl)  ethene
 (4-methyl phenyl)  ethene
 1-chloro  ethene
 dichloro  ethene
 1,2,2 trichloro ethene
 tetrachloro ethene
 1-chloro  propane
 1,  2-dichloro propane
 chloro ethane
 1,  2dichloro ethane
 1-propanol
 1-butanol
 ethanol
methanol
       103

-------
2-butanol
2-methyl, 1-propanol
1-pentanol
1-hexanol
3-hydroxy, 1-propene
1, 2-epoxy butane
1, 2-epoxy propane propylene oxide
3-chloro, 1,2 epoxy propane
1, 2 ethandiol
2 (2 hydroxy ethoxy) ethanol
1, 2 propandiol
2, 3-dihydroxy propanol
3-(3-hydroxy propoxy) propanol
trans-1, 2-dichlora ethene
cis-1, 2-dichloro ethene
1,1,1-trichloroethane
1,1,2,2-tetrachloroethane
butanal
propanal
ethanal
methoxymethane
ethoxyethane
propoxypropane
methoxyethane
methoxypropane
ethoxypropane
2-methoxypropane
2-ethoxypropane
2-(2-propoxy) propane
2-propanone
3-pentanone
4-heptanone
2-butanone
3,3-dimethyl, 2-butanone
1-chlorohexane
1 chloropentane
1 chlorobutane
2-chlorohexane
2-chloropentane
2-chlorobutane
2, chloropropane
3-chlorohexane
3-chloropentane
ami nome thane
aminoethane
1-aminopropane
1-aminobutane
1-aminopentane
1-ami nohexane
2-aminopropane
2-aminobutane
2-aminopentane
chlorine, monotomic
chlorine, monotomic  charged  +  (unipositive  ion)
chlorine, monotomic  charged  -  (uninegative  ion)
                      104

-------
chlorine
chlorine monoxide
chlorine dioxide
dichlorine monoxide
cyanogen chloride
hydrogen monatomic
proton  (H-f)
hydrogen uninegative ion
hydronium unipositive ion
hydrogen
hydroperoxyl
water
hydrogen peroxide
hydrogen chloride
hydrogen oxychloride
formyl
formaldehyde
hydrogen cyanide
nitroxyl
nitrous acid  cis & trans
nitric acid
hydrogen isocyanate
nitrogen monotomic
    "        "       unipositive ion
    "        "       dipositive ion
    "        "       tripositive ion
nitrogen diatomic    unipositive ion
                     uninegative ion
nitric oxide unipositive ion
nitrogen diatomic
imidogen (NH)
amidogen (NH_)
ammonia
hydrazine gas, liquid, solid
nitrogen tetraoxide gas, liquid solid
nitric oxide
nitrogen dioxide uninegative ion
nitrogen trioxide
dinitrogen monoxide
dinitrogen trioxide
dinitrogen pentoxide
nitrosyl chloride
nitryl chloride
ammonium chloride crystal
ammonium perchlorate crystal
oxygen monatomic
oxygen unipositive ion
oxygen uninegative ion
oxygen diatomic uninegative
hydroxyl unipositive ion
hydroxyl uninegative ion
oxygen monatomic 2+
                 3 +
oxygen diatomic
oxygen triatomic
hydroxyl
                     105

-------

-------
                             APPENDIX B

                 KINETIC MODELS AND PARAMETERS

   Presented in this section is a brief description-of the mathematical models,
computer models, and estimated rate data employed in the waste plastics kinetic
analysis.
                                  107

-------
To 1
Set All
Variab1es=0
i
r
                  Read
                  Data
                Print
                Case No.
                Ibs/yr
            Calculate Rate
            Constant Mass
            Distributions
            Initial  Enthalpy
          Calculate Heat
          Required (N£ gas)
          to Bring Waste
          Plastic Mass to
          Reaction Temperature
Figure 40.   Computer program flow diagram.
                  108

-------
                 Figure 40.  Computer program flow diagram (continued)
                        Print
                        Variables
                            If
                         Reactor
                       Distance  (Z)
                       <. Reactor
                          Length
                           If
                       Zero Order
                     Reaction Stage
                      of Mechanism
                                                   If
                                                Reactor
                                               Distance (Z)
                                                 <_ Reactor
                                                  Length
Calculate Zero
Order and First
Order Reaction
Concentrations
   If
Distance
at Print
 Point
                                              Integrate Empirical
                                              Expansion Describing
                                              Final Reaction Stage
                            109

-------
               Figure 40.  Computer program flow diagram (continued)
Execute
Subroutine
Out
                           No
                                           Execute
                                           Subroutine
                                           Out
                                               If
                                            Specified
                                         Waste Plastic
                                            Material
                                            Remains
                              no

-------
Figure 40.  Computer program flow diagram (continued),
       SUBR0UTINE 0UT
           Calculate
           Required
           Heat
         Calculate
         Heat Carrier
         Gas  Require-
         ments
         Calculate
         Solid  and
         Gas  Residence
         Time
                          ill

-------
Figure 40.  Computer program flow diagram  (continued)
     Print
     Output
     Return
                        112

-------
                       TABLE 34

         VARIABLES USED IN MATHEMATICAL MODEL
   M  =  original polymer feed  (gr sec •-)

MHC1  =  original HC1 feed  (gr sec"1)

  M   =  original polymer involved in random degradation
         (gr.sec"1)

  M   =  original polymer involved in zero order degradation
         (gr.sec"1)

  Mn  =  original polymer involved in final stage of
         degradation  (gr.sec"1)

   N  =  total mass of gas product  (gr.sec"1)

  n   =  mass of gas product due to random reaction  (gr.sec"1)

  n   =  mass of gas product due to zero order reaction
   Z     (gr.sec"1)

  nr  =  mass of gas product due to final stages of reaction
         (gr.sec"1)

nHCl  =  mass of HC1 product  (gr.sec"1)

  nO  =  moles of styrene product  (moles.sec"1)

  nl  =  moles of  (ortho,meta,para)  V        2  (moles.aec-l)
                                    C]
                                      I

  n2  =  moles of   // \^  CHC1CH2CL        (moles.sec-i)
                                     /   CHC1CH2CL
  n3  =  moles of  (ortho,meta,para) /  A            (moles.sec"1)



 Cl_  =  moles of Cl_  (moles.sec"1)

nR-H  =  moles aliphatic material  (moles.sec"1)

   Z  =  distance along reactor  (cm)

 ADP  =  average degree of polymerization

  k,,  =  random rate constant  (related to  sec"1)
                          113

-------
            TABLE 34  (continued)
k   =  zero order rate constant  (related  to  sec   )
 z


 p  =  density of waste plastic  at  z  (gr  . cm~^)



p0  =  density of unreacted waste plastic (gr  .  cm~3)

                                 f\

 V  =  void space of reactor  (cmz)



 t  =  time (sec)



MW  =  molecular weight  (gr . gr-mole   )



 A  =  cross sectional area of reactor  (cm  )



 T  =  Temperature  (K)
                        114

-------
                          TABLE  35

     THERMAL DECOMPOSITION DIFFERENTIAL  RATE  EQUATIONS*

     (i)   dN  =rdnr+  dnz  j-  dn ~i  . /    M     ,
          are   Lair"    3t~  '   airJ   (ADP-MW   '
          dn
(2)
(3)
(4)
(5)
(6)
r = k • M
dt r r
dn
z = k
dt
•? - k COS ( nj)
dt z z • M^
dz M dp
dt \- (1-V) dt
dn" d)1' ^,4- U
	 ]_ = j dt whi
dz dt ' dz
                                           -  2HC1)  3/2
                                             MHCI
* It was assumed that the three plastics underwent thermal
decomposition by a three-stage mechanism as  follows:   (1)
an initial random degradation reaction (2)  a zero order
reaction, and (3) a final stage characterized by an empirical
expression.

+ Applicable to polyvinyl chloride system.
                          115

-------
                         TABLE 36
     WASTE PLASTIC(S)/CIDIFFERENTIAL RATE EQUATIONS
                =  &L
          ut         dt     dt      ADP-MW
          dn
     (2)   —£   =  M  . k
          dt        r    r

     (3)   	t_   =  k  cos (T»   n^)
          dt        r      2 '  M,

     (4)   dz    =  (   M   ) .  d
          dt        A-(1-V)     d

     (5)   dnj   =  dnj      dt  where j=r or ^?
          dz       dt    '  dz

     (6)* dnHCl =  dt   •  MHC1   •  kHCl  (1 - nHCl)  3/2
           dz      dz                         MHC1
* Applicable to polyvinyl chloride system.
                           116

-------
                         TABLE 37

   DECOMPOSITION PRODUCTS/CI  DIFFERENTIAL  RATE EQUATIONS*
                            2
     (1)  dnO
          dt
                                 V
     (2)   ^1   =  n
          dt          2
     (3)  dnz   =  n     |n k   -  n k ]
          dF~       Cl,   0 A      2 ET
(4)   dn3    =
     dt

     dncl
(5)       2 =
      dt
                    Cl.
                                             + n2kD = nR-H
     (6)  dnHCl =
            dt
nicl2
                               n2ko
     (7)   dnRH  =
           dt
               RH
*Reactions
(a)
         CHCH2
                            ^     CHC1CH2C1
(b)
        //\\  CHCH2  +  C12
                                               CHC1CH2C1
      Cl
                                               Cl
(c)
              CHCH
                                         ^     CHCH2
                                              Cl
                                                           + HC1
(d)
                     Cl
                    + Cl
                                                CHC1CH2C1
                                                           + HC1
                                              Cl
                            117

-------
                   TABLE 37 (continued)
(e)   R-H +  Cl-  -*•   R-C1  + HC1 where R equals various
     saturated  and unsaturated hydrocarbons with various
     degrees  of Cl substituting.
                            118

-------
                          TABLE  38




            THERMAL DECOMPOSITION PRODUCTS/AIR


              DIFFERENTIAL RATE  EXPRESSIONS*
(1)+ d
(2)+ d

(^c=cC)
dt
0
dt
~ kl (R-H)
0
*d(xc%)
dt
(o2)
= k(
B
(>>C<) (OH)

          d(C02)    ^ d(H20)    ^  k,   (
            dt          dt
* The differential rate  expressions were not programmed into

  equivalent computer programs.   As such,  these above rate

  expressions were used  to  characterize the systems.



+ The preliminary kinetic analysis  equations are (see

  reference 1) the following:



  (A)  R + 02 £  H02  +   ^C=c(





  (B)  HO   + RH  -» HO H +  R





  (C)  M + HO      -»  20H  + M


                                  O


  (D)  Jb=c'   + HO  ->   OH  +   ^C-CX





  (E)  /C=C^ + OH   +  O -»   HO -   ^p-C7  - O-O


                                  O

           .           >    '       \> \ '       \
  (F)  EO-C-C-0-O +  C=C   -»   ^-C    +  XC=O  + HO~CH2





  (G)  RH   +   20   ~»   R  +  2H O   + CO
         J        ^              £*       &,
                           119

-------
                         TABLE 39
     WASTE PLASTICS (SOLID)/AIR DIFFERENTIAL RATE EXPRESSIONS
       (1)*   N.  =  K  '   M

             dt
                   ~i   -  k^ (R-H)(02)
                 dt

                              0
                dt           dt



                                  =  kl

              dt            dt
                                          2
                                      C   2
* Oxidation opcurs in a random reaction to yield intermediate

  gas products from the solid waste material.



+ See note 2 on Table 38.
                           120

-------
                       TABLE 40




PREDICTED RESULTS COMPARED WITH EXPERIMENTAL RESULTS
STY RENE
Based on 1.

Calculated
970 K @ 2.5 min
Styrene 0.81
Toluene and
ethylbenzene 	
Residue 0.19
gr/sec polystyrene feed
(17)
Experimental
898 K
g 0.74 g

Trace "
g 0.26 "
POLYETHYLENE
Based on 1

Calculated
710 K @ 50 min
C2H 0.018 g
C2H 0.055 g
C3H 0.0015 g
C3H6 0.0325 g
C_HQ 0.0960 g
J o
C4Hg 0.1990 g
C4H1Q 0.1585 g
C5Hg 0.0035 g
C5H1Q 0.0765 g
C5H12 0.0640 g
C6H10 0.0040 g
C6H12 0.0395 g
C6H14 0.0165 g
C7H1 0.0030 g
C?H16 0.0060 g
Unreacted 0.2265 g
gr/sec polyethylene feed
(18)
Experimental
702 K @ 30 min
0.016 g
0.048 g
—
0.028 g
0.085 g
0.177 g
0.144 g
0.003 g
0.068 g
0.057 g
0.003 g
0.035 g
0.014 g
0.002 g
0.005 g
0.373 g
                         121

-------
             TABLE 40 (continued)
              POLYVINYL CHLORIDE
           Based on 1 gr/cc polyvinyl

   Calculated
723 K @ 4.25 rain
HCl
H2
CH4
C2H6
C2H4
C6H6
C7H8
Other
Residue
0.510
0.0023
0.0144
0.0371
0.0718
0.0567
0.0302
0.1875
0.0900
g
g
g
g
g
g
g
g
g
            (19'
Experimentalx  '

873 K with H
                                   0.555
                                   0.0006
                                   0.0100
                                   0.0069
                                   0.0052
                                   0.0560
                                   0.0067


                                   0.0630
         g
         g
         g
         g
         g
         g
         g
         g
         g
                   122

-------
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                                                                            123

-------
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GRMSEC = C8H8*104. 1.4
IF BUG FO I THEN PR




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-------
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                                                                           125

-------
                         TABLE  42

                  KINETIC RATE  PARAMETERS


A (

'base


mole

1
•sec
E (Kcal/mole)
• Thermal decomposition
Polystyrene
Random RXN
Zero order
Polyethylene
Random RXN
Zero order


RXN


RXN







1.
4.




92
33

t
f

x
x




10
10




12
9




44.
44.

*
*

7
7



Polyvinyl chloride
Random RXN
Zero order
HC1 RXN

RXN



§
4.
1.
1.
8
9
9
X
X
X
10
10
10
10
9
9
44.
44.
33.
2
2
0
• Plastic (solid) /C12
Polystyrene
Polyethylene




Polyvinyl chloride
• Decomposition
RXN A
RXN B
RXN C
RXN D
RXN E
• Decomposition
RXN 1
RXN 2
RXN 3
• Waste plastic
Polystyrene
Polyethylene
(g)/ci2





(g)/air



(solid)/air


Polyvinyl chloride

§
§
i
§
§

§
§
§

§
§
§
3.
1.
5.

3.
2.
4.
4.
1.

2
1
3.

2
1
2
4
9
0

2
1
0
0
0



2




X
X
X

X
X
X
X
X

X
X
X

X
X
X
10
10
10

10
10
10
10
10

10
8



5
5
6
Q
u

8
1015
10

10
y

9
Q
10-
10
/
32.
31.
30.

17.
17.
23.
23.
1.

10,
43.
9.

40.
44.
44.
2
0
0

0
0
5
5
0

00
0
0

7
7
7
* E =  27586.  +  46.853  x ADP.
f A =  EXP  (42.4 +  0.1445 x
t A'=  4  x  102 x A.
§ Units  in sec"1 (pressure units).
                               126

-------
                              APPENDIX C

                           ECONOMIC MODELS

   This appendix contains brief descriptions of some  of the computer models
(subroutines)  used  in  the economic analyses of chemical systems for waste
plastic utilization.  These subroutines  are  called by the main program when
needed and were written to calculate the capital and operating costs' associated
with that specific piece of equipment.

                           Subroutine COMPRS

   Subroutine COMPRS calculates the actual brake horsepower required to drive
a  compressor. A  mechanical  efficiency  of  94 percent  and a  compression
efficiency  of 83.5  percent were assumed. The  intake  and exit  volumes are
calculated based on  stream composition, entrance and exit temperatures, and the
input-output  pressure ratio. Subroutine ECON is then called to determine the
more economical type  of compressor, the installed cost of the compressor, and
the operating cost in dollars per hour.

                            Subroutine ECON

   Subroutine ECON determines which type of compressor is more economical,
centrifugal or reciprocating. The subroutine calculates the capital cost of each
type of compressor  for  the brake horsepower required and the operating cost per
hour  based on  which source  of power is chosen,  steam  or  electricity. The
resultant costs for each type of compressor are compared and the smaller of the
two is chosen.
                                 127

-------
                             Subroutine SEPAR

   Subroutine SEPAR calculates the minimum required volume of a vapor-liquid
gravity settling tank. As the vapor passes upward through the tank, particles with
terminal velocities  equal to  or greater than the vertical velocity of the vapor
stream will be removed. A particle terminal velocity of 1 ft/sec was assumed to
exist in the  settler, and a tank height of 10 ft was assigned.  The subroutine then
calculates the area required  to decrease  the vapor velocity  to  1 ft/sec.  The
installed cost of the vessel is determined as a function of vessel capacity.

                              Subroutine REF

   Subroutine REF calculates the brake horsepower required to refrigerate  the
product to the desired temperature. Based on the change in enthalpy,  the type
of power specified for  driving the refrigerator, and the materials involved,  the
installed cost is determined.

                             Subroutine EXCH

   Subroutine EXCH calculates the square feet of heat exchanger required based
on  the heat load in Btu per hour, and the inlet and exit temperatures.  The
capital cost  is then calculated from the area required and the operating  pressure.

                             Subroutine PUMP

   Subroutine PUMP calculates the gallons of liquid per minute that must be
moved by a process pump. The capital  cost is then  calculated as a function of
flow (gal/min).

                             Subroutine BCCOL

   Subroutine  BCCOL  calculates  the   minimum   allowable  diameter  of  a
bubble-cap  distillation column.  A column must have  sufficient cross  sectional
area to handle the rising gases  without excessive carryover of liquid from  one
tray to another. The vapor velocity
 where: PT ,  *Q = density of liquid and vapor, respectively.
                                    128

-------
                               APPENDIX D
               ASSUMPTIONS MADE IN ECONOMIC ANALYSES
                                  Utilities
 Cooling water
 Electrical power
 Fuel Gas
 Boiler water
 Steam
2
-------
Environmental Protection Agencj
Libra*/  Ifag .'cr;  7
1 fi c>v t ]f\ V/&0. - -" Drive
rniv^gj, Illinois   60606

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U.S. ENVIRONMENTAL PROTECTION AGENCY

-------