Report No. 72

PETROLEUM COKE

by SAMUEL C. SPENCER

October 1971

A private report by the 0 PROCESS ECONOMICS PROGRAM

STANFORD RESEARCH INSTITUTE MENLO PARK, CALIFORNIA I * CONTENTS

1 INTRODUCTION, ...... 1

2 SUMMARY ...... * ...... , . .

Economic Aspects ...... 6 Technical Aspects ...... 10

3 INDUSTRY STATUS ...... , . . . . , , . . . 17 Trends ...... 17

Applications . . , ...... 29 Fuel ...... 31 Aluminum (anodes) ...... 32 MetallurgicalCoke ...... 36 Chemicals ...... 37 Formed Shapes ...... 38 Other Uses . . . , ...... 39

4 DEVELOPMENTOF COKING PROCESSES . . . , , , , . . . . . , . 41

5 CHEMISTRY ...... 47

Composition ...... 47 Basic Chemistry ...... 52

6 DELAYED COKING...... 59 Review of Process ...... 59 Process Description ...... 68 Materials of COnStrUctiOn ...... 83 Process Discussion ...... 84 Process Variations and Innovations ...... 93 Cost Estimates ...... 95 Capital Costs ...... 96 Production Costs ...... 100 Needle Coke Economics ...... 112

V CONTENTS

7 FLUID COKING ...... 119 Review of Process ...... 119 Process Description ...... 129 Materials of Construction ...... 133 Process Discussion ...... 140 Process Variations and Innovations ...... 144 Cost Estimates ...... 149 Capital Costs ...... 150 Production Costs ...... 153 Flexicoking ...... 164

8 CALCINING OF COKE ...... 167

Technology ...... 167 Industry Status ...... 170 Process ...... 171 Innovationsand Developments ...... 175 Cost Estimates ...... 177

9 DESULFURIZATION OF COKE ...... 181

10 REMOVAL OF ASH AND METALLIC CONTAMINANTSFROM COKE. .... 189

11 GRAPHITE FROM COKE ...... 193

12 INNOVATIONSAND DEVELOPMENTS IN COKE TECHNOLOGY ...... 203

APPENDIX A DESIGN AND COST BASIS ...... 209

CITED REFERENCES ...... 213

PATENT REFERENCES BY COMPANY ...... 243

Vi ILLUSTRATIONS

2.1 Coke Yield vs Conradson Carbon Content . . . , . . , . , . 14 3.1 Capacity of Residual Upgrading Installationsin the United

States l ...... 19 3.2 Coke Production as Percentage of Crude Oil Processed in the United States ...... , . , ...... 20 3.3 Schematic of Role of Coking in Petroleum Refining . . . . 21 5.1 Change in the PhysicochemicalProperties of Coke on Heating ...... 57 6.1 Petroleum Coke by Delayed Process RelationshipBetween Coke Yield and Feedstock Gravity and Carbon Content ...... , ...... 61 6.2 Petroleum Coke By Delayed Process Effect of Feedstock Gravity on Yields of All Products . , 62 6.3 Petroleum Coke by Delayed Process Effect of Recycle Ratio on Yields . . . . , . . . . , . . 64 6.4 Petroleum Coke by Delayed Process Processing Operations ...... , , . . . , . 77 6.5 Petroleum Coke by Delayed Process Product Handling ...... 81 6.6 Petroleum Coke by Delayed Process Zone of Critical Decomposition ...... 86 6.7 Petroleum Coke by Delayed Process Influence of Capital Investmenton Payout Period . . . . . 109 6.8 Petroleum Coke by Delayed Process Influence of Heavy Gas Oil Value on Payout Period . . . . 110

6.9 Petroleum Coke by Delayed Process Influence of Coke Value on Payout Period ...... 111 7.1 Petroleum Coke by Fluid Process Maximum Permissible Feed Rate vs Coke Yield ...... 123

vii ILLUSTRATIONS

7.2 Petroleum Coke by Fluid Process Maximum Feed Rate at Various Conversion Rates . . , . , . 125

7.3 Petroleum Coke by Fluid Process Feed Rate vs Fluid Coking Temperature ...... 126

7.4 Petroleum Coke by Fluid Process Processing Operations ...... , . , , . . . . 137 7.5 Petroleum Coke by Fluid Process Capital Investment,Battery Limits Plant . . , ...... 156 7.6 Petroleum Coke by Fluid Process Influence of Capital Investment on Payout Period . . . . . 160 7.7 Petroleum Coke by Fluid Process Influence of Gasoline Value on Payout Period . . . . , . . 161 7.8 Petroleum Coke by Fluid Process Influence of Heavy Gas Oil Value on Payout Period . . . . 162 7.9 Petroleum Coke by Fluid Process Influence of Coke Value on Payout Period , ...... 163 7.10 Flexicoking . . . , ...... 166 11.1 Variation in Properties Across Radius of a 13 Inch Diameter Extruded Fine-GrainedGraphite Cylinder . . . , . 198 11.2 Change in Room Temperature Resistivity of a Graphite Rod in Relation to Temperature of Graphitization . , , . . . , 198 11.3 Resistivity of Graphite Electrodes vs Temperature , . . , 199 11.4 Thermal Conductivity of Fabricated Graphite ...... 199 11.5 Mean Specific Heat of Graphite , , . . , , . , , , . , . , 200 11.6 LongitudinalThermal Expansion of Fabricated Graphite . . 200

viii TABLES

2.1 Summary of Coking Economics . . , ...... 8 3.1 Production of Green Petroleum Coke ...... , . . . . . 23 3.2 Petroleum Coke Plant Capacities in the United States . . . 24 3.3 Petroleum Coke Plant Capacities in Canada . . . , . . . . 25 3.4 Coker Feed and Coke Output Capacities in the United States...... 25 3.5 Coke Requirements for Aluminum Production ...... 26 3.6 Petroleum Coke Calcining Capacities in the Free World , . 27 3.7 Annual Coke Consumption in Japan ...... 28 3.8 Comparison of Fuel Characteristics ...... 31 3.9 Estimated Requirements for Carbon Components in Anode Manufacture at Selected Alumina Reduction Plants in the United States ...... , . . . 34 3.10 RepresentativeSpecifications for Cokes for Use in the Manufacture of Electrodes for Alumina Reduction Plants on the West Coast ...... 35

4.1 Properties of Petroleum Cokes ...... 45 5.1 RepresentativeAnalyses of Selected Raw Cokes and Other CarbonaceousMaterials . . . . , ...... , 48 5.2 RepresentativeAnalyses of Raw Delayed Cokes , . . . . , , 48 5.3 RepresentativeAnalyses of Raw Fluid Cokes ...... , 49 5.4 Typical Ranges for Analyses of Petroleum Cokes ...... 50 6.1 Petroleum Coke by Delayed Process Major Process Equipment and Utilities Summary ...... 77 6.2 Petroleum Coke by Delayed Process Stream Flows . . . , . . , . . . . . , ...... 80 6.3 Petroleum Coke by Delayed Process Major Product Handling Equipment Summary . . , . . . . . , 81

IX TABLES

6.4 Petroleum Coke by Delayed Process Total Capital Investment ...... , ...... 104

6.5 Petroleum Coke Handling by Coke Pit System Total Capital Investment . . . , ...... , . . 105

6.6 Petroleum Coke by Delayed Process Annual Production Costs . , . , , , . , , ...... 106

6.7 Petroleum Coke by Delayed Process Profitability--Payoutof Investment ...... 107

6.8 Petroleum Coke by Delayed Process Coke Handling Costs ...... 108

6.9 Needle Coke/RegularCoke Total Capital Investment . . . , ...... , ...... 114

6.10 Petroleum Coke by Delayed Process, IncludingNeedle Coke on Blocked Operations Annual Production Costs . . , ...... 115

6.11 Petroleum Coke by Delayed Process, IncludingNeedle Coke on Blocked Operations Profitability--Payoutof Investment ...... 117

7.1 Petroleum Coke by Fluid Process Effect of Recycle Cut Point on Product Distribution . . . 121

7.2 Petroleum Coke by Fluid Process Major Process Equipment and Utilities Summary ...... 137

7.3 Petroleum Coke By Fluid Process Stream Flows . . . . , ...... , ...... 139

7.4 Petroleum Coke by Fluid Process Operating for Higher Butene Yields . . . , . . . . . , . . 143

7.5 Petroleum Coke by Fluid Process Total Capital Investment ...... , . . . , . . . . 157 7.6 Petroleum Coke by Fluid Process Annual Production Costs , ...... , ...... 158

X TABLES

7.7 Petroleum Coke by Fluid Process Profitability--Payoutof Investment ...... 159 8.1 Typical Properties of Petroleum Coke Used in Carbon and Graphite Manufacture . . . . . , ...... 168 8.2 Petroleum Coke Calcining Locations ...... 172 8.3 Petroleum Coke Calcining Total Capital Investment . . . . , ...... , . 179 8.4 Petroleum Coke Calcining Production Costs . . , ...... , . . . , . , . . . , . 180

9.1 Sulfur Content of a Few Petroleum Cokes , ...... 182 11.1 CharacteristicRoom Temperature Physical Properties of Fine-GrainedExtruded Graphite , . . . . . , ...... 194

11.2 Effect of Grain Size on Properties of Extruded Graphite. , 195 11.3 Comparison of Physical Properties of Fine-Grained Graphite--Moldedand Extruded ...... , . . . . . , . 196 11.4 Effect of Grain Size on Anisotropy of Graphite . . , , . . 196 11.5 Other Typical Physical Properties of Graphite ...... 197

Xi