PROCESS ECONOMICS PROGRAM SRI INTERNATIONAL Abstract Mod0 Park, California 94025 Process Economics Program Report No. 176 STYRENE AND p-methylstyrene AND POLYMERS (November 1984) The ethylbenzene dehydrogenation process remains dominant for making styrene; some styrene is coproduced in the manufacture of propylene oxide. The process for making styrene from toluene via stilbene and that for making styrene from toluene and methanol are not yet economic. Costs for these processes are presented. We have evaluated processes for three types of polystyrene: general purpose polystyrene (GPS), impact-modified polystyrene (IPS), and expandable polystyrene (EPS). GPS is now universally made by the continuous bulk process; IPS is mostly and preferably made by the continuous bulk process, although batch suspension and batch bulksuspension processes are still used; EPS is made by the batch suspension process. Copolymers of styrene with maleic anhydride, methyl methacrylate, and acrylic acid, respectively, are also evaluated. The copolymer with acrylic acid has a low molecular weight. We also evaluated the manufacture of p-methylstyrene from toluene and ethylene. Costwise p-methylstyrene is barely competitive with styrene. Its polymers have some performance advantages over those of styrene, but these are not sufficient to justify substantial replacement. With surplus production capacity for styrene already in place, the growth of p-methylstyrene is expected to be slow. PEP'84 YCY
Report No. 176 STYRENE AND p-methylstyrene AND POLYMERS by YEN-CHEN YEN with contrtbutlons by JONG-TAIN HUANG a t cl I m A private report by the November 1984 PROCESS ECONOMICS PROGRAM Menlo Park, California 94025
. For detailed marketing data and information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMICAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PETROCHEMICALS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI DIRECTORY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States and Western Europe. ii
CONTENTS 1 INTRODUCTION... 2 SUMMARY.......................... Commercial Aspects... Economic Aspects... Styrene and Polymers... p-methylstyrene and Polymers... Technical Aspects... Styrene from Benzene and Ethylene via Ethylbenzene... Styrene from Toluene and Ethylene via Stilbene... Styrene from Toluene and Methanol... p-methylstyrene from Toluene and Ethylene... General Purpose Polystyrene... Impact Modified Polystyrene... Expandable Polystyrene... Poly(Styrene Maleic Anhydride)... Poly(Styrene-Methyl Methacrylate)... Poly(Styrene-Acrylic Acid)... 3 INDUSTRY STATUS...................... 4 STYRENE PROM BENZENE VIA ETHYLBENZENE... Chemistry... Review of Processes... Evaluation of an Integrated Plant Producing Styrene from Benzene via Ethylbenzene... Process Description... Process Discussion... Cost Estimates.... Ethylbenzene Production... 5 OTHER PROCESSES FOR PRODUCING STYRENE... Styrene from Pyrolysis Naphtha... Styrene from Ethylbenzene by Oxidative Dehydrogenation... Styrene from Toluene and Ethylene via Stilbene... Styrene from Toluene and Methanol... Styrene from Benzene and Ethylene Oxide... Styrene from 4-Vinylcyclohexene... Styrene Coproduced with Propylene Oxide from Ethylbenzene via Hydroperoxide... Conclusions... 1 3 3 4 4 5 11 11 12 12 12 13 13 13 14 14 15 17 39 39 39 40 41 52 55 63 67 67 67 68 68 70 70 70 71 iii
CONTENTS 6 p-methylstyrene....... 79 Chemistry... Review of Processes... io Process Description... Process Discussion... ii: Cost Estimates.... 92 7 POLYSTYRENE... 101 Chemistry... 101 Review of Processes... 102 Bulk (Mass) Process... 102 Suspension Process (and Bulk-Suspension Process)... 107 Emulsion Process... 110 Solution Process... 111 General Purpose Polystyrene by a Bulk Process... 112 Process Description... 112 Process Discussion... 119 Cost Estimates... 120 Impact Modified Polystyrene by a Bulk Process... 128 Process Description... 128 Process Discussion... 132 Cost Estimates... 132 Expandable Polystyrene by a Batch Suspension Process... 141 Process Description... 141 Process Discussion... 148 Cost Estimates... 148 IPS by Batch Suspension Process... 154 8 COPOLYMERSOFSTYRENE... 157 Chemistry... 157 Review of Processes... 158 Styrene-Maleic Copolymers....' 158 Styrene Copolymers with Methacrylate or Acrylic Acid... 159 Other Copolymers... 159 A Batch Solution Process for Manufacturing a Rubber-Modified Copolymer of Styrene and Maleic Anhydride... 160 Process Description... 160 Process Discussion... 163 Cost Estimates... 163 iv
CONTENTS a COPOLYMERS OF STYRENE (continued) A Continuous Bulk Process for Manufacturing a Rubber- Modified Copolymer of Styrene and Methyl Methacrylate... 172 Process Description................... 172 Process Discussion.................... 174 Cost Estimates...................... 174 A Continuous Bulk Process for Manufacturing a Low Molecular Weight Copolymer of Styrene, alpha-methylstyrene, and AcrylicAcid... 181 Process Description................... 181 Process Discussion.................... 182 Cost Estimates...................... 183 General Comments on Costs for Making Copolymers...... 189 9 POLYMERS OF p-methylstyrene... 191 Chemistry ;... 191 Review of Processes... 192 Properties of p-methylstyrene Polymers... 192 Specific Gravity... 192 Cross-Linking... 193 Heat Distortion Temperature and Vicat Softening Temperature... 193 Transparency, Color... 193 Mechanical Strength... 194 MeltFlow... 195 Susceptibility to Other Additives... 195 Prospects for p-methylstyrene... 195 p-methylstyrene at 55c/lb... 197 p-methylstyrene at 38c/lb... 198 p-methylstyrene at 32c/lb... 203 APPENDIX A PROPERTIES OF COMMERCIAL STYRENE POLYMERS..... 205 APPENDIX B SOME USEFUL INFORMATION FOR DESIGN OF PS REACTIONS................... 207 PATERTSUMMARYTABLES... 211 CITED REFERENCES........................ 289 PATENTREFERENCES........................ 337 V
ILLUSTRATIONS 3.1 Interrelationships between Ethylbenzene, Styrene, and Polystyrene..................... 18 4.1 Styrene from Benzene and Ethylene by Alkylation and Dehydrogenation FlowSheet... 353 4.1A Dehydrogenation Reactor................. 45 4.2 Styrene from Benzene via Ethylbenzene Effect of Operating Level and Plant Capacity on Production Cost.................... 61 5.1 Styrene by Methanol Alkylation of Toluene Flowsheet.... 359 6.1 p-methylstyrene from Toluene FlowSheet... 361 6.2 p-methylstyrene from Toluene Effect of Operating Level and Plant Capacity on Production Cost.................... 99 7.1 General Purpose Polystyrene by a Continuous Bulk Polymerization Flowsheet... 367 7.2 General Purpose Polystyrene by a Continuous Bulk Polymerization Single Line Plant Effect of Operating Level and Plant Capacity on Product Value..................... 127 7.3 Impact Modified Polystyrene by a Continuous Bulk Polymerieation (Reaction Section) Flowsheet... 369 7.4 Impact Modified Polystyrene by a Continuous Bulk Polymerization Single Line Plant Effect of Operating Level and Plant Capacity on Product Value..................... 139 7.5 Expandable Polystyrene by a Batch Suspension Polymerization Flowsheet... 371 a.1 Poly(Styrene-Maleic Anhydride) By a Batch Solution Process Flowsheet... 373 Vii
ILLUSTRATIONS a.2 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Flowsheet... 375 8.3 A Low Molecular Weight Copolymer of Styrene, eiethylstyrene and Acrylic Acid By a Continuous Bulk Process Flowsheet... 377 9.1 p-methylstyrene Product Value as a Function of Plant Capacity...................... 196 B.l Viscosity of PS (M = 60,000) and Recommended Ranges of Agitators................... 207 B.2 Relative Heat Transfer Coefficient as a Function of Percent Polystyrene Solids Based on Viscosity Relationship Shown in Figure B.l............. 208 B.3 Vapor Pressure of p-methylstyrene and p-ethyltoluene... 209 Viii
TABLES 2.1 Cost Features of Styrene Production... 7 2.2 Cost Features of Polystyrene Production... 8 2.3 Cost Features of Styrene Copolymer Production... 9 2.4 Cost Features of p-methylstyrene Production... 10 3.1 World Ethylbenzene and Styrene Producers in 1984... 21 3.2 Styrene Production in 1982... 26 3.3 Styrene Markets... 26 3.4 World Polystyrene Producers in 1984... 27 3.5 Major Producers of Styrene and Polystyrene and their World Capacities... 35 3.6 Polystyrene Production in 1982... 35 3.7 Polystyrene Markets... 36 3.8 World Styrene Copolymer Producers in 1984... 37 4.1 Ethylbenzene from Benzene and Ethylene by Alkylation Patent Sunnnary... 212 4.2 Styrene from Ethylbenzene by Dehydrogenation Patent Sunnnary... 219 4.3 Styrene from Benzene via Ethylbenzene Design Bases and Assumptions... 42 4.4 Styrene from Benzene via Ethylbenzene Stream Flows... 47 4.5 Styrene from Benzene via Ethylbenzene Major Equipment... 49 4.6 Styrene from Benzene via Ethylbenzene Utilities Summary... 51 4.7 Styrene from Benzene via Ethylbenzene Total Capital Investment... 57 4.8 Styrene from Benzene via Ethylbenzene Production Costs... 59 4.9 Comparison of Different Design Bases... 62 4.10 Ethylbenzene by Vapor Phase Alkylation Production Costs... 64 IX
TABLES 5.1 Oxidative Dehydrogenation for Making Styrene from Ethylbenzene Patent Summary...................... 230 5.2 Styrene from Toluene and Ethylene via Stilbene Production Costs..................... 72 5.3 Styrene by Methanol Alkylation of Toluene Total Capital Investment................. 74 5.4 Styrene by Methanol Alkylation of Toluene Production Costs..................... 76 6.1 Catalyst for Alkylation of Toluene or Ethylbenzene Patent Summary... 232 6.2 Methylstyrene from Ethyltoluene by Dehydrogenation Patent Summary... 234 6.3 p-methylstyrene from Toluene Design Bases and Assumptions............... 83 6.4 p-methylstyrene from Toluene Stream Flows....................... 86 6.5 p-methylstyrene from Toluene MajorEquipment..................... 88 6.6 p-methylstyrene from Toluene Utilities Summary.................... 90 6.7 p-methylstyrene from Toluene Total Capital Investment................. 95 6.8 p-methylstyrene from Toluene Production Costs..................... 97 6.9 p-methylstyrene from Toluene 35 Million lb/yr Capacity Production Costs..................... 100 7.1 Reactors for Polystyrene Bulk Process.......... 103 7.2 Bulk (Mass) Polymerization for Making General Purpose Polystyrene Patent Summary... 236 7.3 Bulk (Mass) Polymerization for Making Impact Modified Polystyrene Patent Summary... 241 X
TABLES 7.4 7.5 7.6 Some Commercial Continuous Bulk Processes for Making Polystyrene.................. 105 Effect of Bulk Process Production Conditions on Properties of Polystyrene............... 108 Suspension Polymerization for Making General Purpose or Impact Modified Polystyrene Patentsummary... 246 7.7 Bulk-Suspension Process for Polymerization of Styrene Patent Summary..... 250 7.8 Expandable Polystyrene Patent Summary...................... 252 7.9 Compositions of Polystyrene Patent Summary...................... 258 7.10 Devolatilization of Polystyrene Patentsummary... 260 7.11 Miscellaneous Processes for Styrene Polymerization Patent Summary.....,................ 261 7.12 General Purpose Polystyrene by Bulk Polymerization Design Bases and Assumptions............... 113 7.13 General Purpose Polystyrene by Continuous Bulk Polymerization Stream Flows....................... 116 7.14 General Purpose Polystyrene by Continuous Bulk Polymerization Major Equipment..................... 117 7.15 General Purpose Polystyrene by Continuous Bulk Polymerization Utilities Summary.................... 118 7.16 General Purpose Polystyrene by Continuous Bulk Polymerization Total Capital Investment................. 122 7.17 General Purpose Polystyrene by Continuous Bulk Polymerization Production Costs..................... 124 7.18 General Purpose Polystyrene by Bulk Polymerization Costs for Multiline Plants................ 126 xi
TABLES 7.19 Impact Modified Polystyrene by Bulk Polymerization Design Bases and Assumptions............... 129 7.20 Impact Modified Polystyrene by Continuous Bulk Polymerization Major Equipment..................... 130 7.21 Impact Modified Polystyrene by Continuous Bulk Polymerization Total Capital Investment................. 134 7.22 Impact Modified Polystyrene by Continuous Bulk Polymerization Production Costs..................... 136 7.23 Impact Modified Polystyrene by Bulk Polymerization Costs for Multiline Plants................ 138 7.24 Polystyrene by Bulk Polymerization Comparison of Cost Estimates............... 140 7.25 Expandable Polystyrene by Suspension Polymerization Design Bases and Assumptions............... 142 7.26 Expandable Polystyrene by Batch Suspension Polymerization Stream Flows....................... 144 7.27 Expandable Polystyrene by Batch Suspension Polymerization Major Equipment..................... 146 7.28 Expandable Polystyrene by Batch Suspension Polymerization Utilities Summary.................... 147 7.29 Expandable Polystyrene by Batch Suspension Polymerization Total Capital Investment................. 150 7.30 Expandable Polystyrene by Batch Suspension Polymerization Production Costs..................... 152 7.31 Impact Modified Polystyrene Comparison of Costs for Bulk and Suspension Processes.. 155 a.1 Styrene Maleic Anhydride Copolymers Patent Summary...................... 265 Xii
TABLES a.2 a.3 8.4 8.5 8.6 a.7 8.8 a.9 a.10 8.11 a.12 8.13 8.14 Copolymers of Styrene and Acrylic Acid, Acrylate, and Methacrylate Patent Summary... Copolymers of Styrene and alpha-methylstyrene and Other Styrene Homologues Patent Summary... Styrene Copolymers Similar to ABS Patent Summary... Miscellaneous Copolymers of Styrene Patentsummary... Polystyrene Chemically Modified Patentsummary... Poly(Styrene-Maleic Anhydride) by a Batch Solution Brocess Design Bases and Assumptions............... Poly(Styrene-Maleic Anhydride) by a Batch Solution Process StreamFlows... Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Major Equipment..................... Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Utilities Summary.................... Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Total Capital Investment................. Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Production Costs..................... Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Design Bases and Assumptions............... Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process StreamFlows.................. 274 281 282 283 285 161 164 166 167 168 170 173 175 Xiii
TABLES 8.15 8.16 8.17 8.18 a.19 8.20 a.21 8.22 8.23 a.24 9.1 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Major Equipment..................... 176 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Utilities Summary.................... 177 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Total Capital Investment................. 178 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Production Costs..................... 179 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid Design Bases and Assumptions............... 181 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Stream Flows....................... 184 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process MajorEquipment..................... 185 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Utilities Summary.................... 185 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Total Capital Investment................. 186 Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Production Costs..................... 187 Poly(p-Methylstyrene) Patent Summary... 286 xiv
TABLES 9.2 Copolymers Containing p-methylstyrene or p/m-methylstyrene Patent Summary...................... 287 9.3 Blends and Applications of Poly(p-Methylstyrene) Patent Summary...................... 288 9.4 Use of p-methylstyrene Instead of Styrene........ 200 9.5 Estimation of Market Penetration of p-methylstyrene in the United States................... 202 xv