Tài liệu Refinery Process modeling :A Practical Guide to Steady State Modeling of Petroleum Processes

REFINERY PROCESS MODELING APractiall Guide to Steady State Modeling 01 Petroleum Processes FIRST EDITION REFINERY PROCESS MODELlNG I ,I i I A Practical Guide to Steady State Modeling of Petroleum Processes (Using Commercial Simulators) First Edition Gerald L. Kaes Consulting Chemical Engineer Chemicall'rocess Simulation Colbert, Georgia The Athens Printing Company Athens, Georgia Refinery Process Modeling First Edition ISBN: 0-9679274-0-4 Copyright (£)2000 by Kaes Enterprises, Inc. All rights reserved. Printed in the United States of America. This book or parts thereof may not be reproduced in any form without permission. Published by: Kaes Enterprises, Inc. 522 Kingston Road Colbert, Georgia 30628 Phone: (706) 788-3366 FAX: (706) 788-3366 emaiI: [email protected] First printing: March 2000 The In/orma!ion contained in this book is believed to be accurate and reasonable. However, the author and;: aes Er.!erpri5cs, Inc. do not guarantee the accuracy or completeness of any in/ormatioll published herelf1 and sha!t nol be responsible Jor any errors, omI5:,-;on5. -or damages arising out of the lIse oJthis rn/orfTlQfi0n Titls book is published with the intent tn supply infurmation and is no! an attempt lo render ('ng; ,':eenng or other professional services. The user of infon,l(J[ion published herein is solely responsible for .he acc;JrC0' and appl;cability ofcalculations based on this information. They say that behind every good man is a good woman. Anything good I have accomplished I owe to my wife Barbara who has encouraged and supported me these many years. This book is lovingly dedicated to her. f F'- At the urging of several colleagues, I decided to record many of the tips and tricks for computer simulation of petroleum processes I have amassed over the past thirty-eight years. In this way, perhaps I can partially repay the technical debt I owe to the many engineers who helped me develop my skills as a young engineer. I was fortunate to begin my career in an era when corporations sought to develop young engineers through intensive training and apprenticeship programs. Unfortunately, the bottom line thinking of today no longer allows such an approach. The young engineer is otlen thrust into a plant environment with little or no training. Hopefully, this book will serve 10 some small capacity to provide some practical training for the younger engineers. If you are looking for technical elegance this may not be the book for you. Frankly, in my experience with modeling petroleum refinery processes (with commercial simulators) I have encountered little that is elegant. I chose to focus onthe more practical aspects of engineenng. Engineering theory is good and necessary; however, it is based on perfect processes and simplifying assumptions. Any practicing engineer knows it is necessary to apply experience factors to reconcile theoretical expressions with real world processes. This is the fOCllS of this book. It is noteworthy to remind the reader that this book was written for steady state models for petroleum processes. By definition, for a steady state process, there is always" perfect mater'ial balance and heat balance. Any engineer who has conducted a plant test knows that real plants seldom operate at steady state. This must always be taken into consideration when developing steady state models. I must also stress that this book was written for engineers who use commercial software for their simuiation efforts. Because of the enormous overhead associated with developing and maintaining simulation software, most corporations today have abandoned their own efforts in favor of a vendor-supplied simulation program. While this is the most cost-effective approach, it is not always the best technical approach. Commercial simulators must be based on open literature methods. This does not allow the use of proprietary data that might be useful in improving the accuracy of simulation results ~ \:everthe!ess. it is possible to develop accurate and useful models for petroleum processes ·..,ith commercial simulators. The author has had extensive experience with the Hyprotecr.. Lld HYSIM, and HYSYS programs, and the SimSci PROVISION" program. Howc\·cr. 'he principles in this book are not simulator specific and may be applied with any simuialOf having tne features required for simulation of petroleum processes. GcraIJ L Kaes : I f I I I I TABLE OF CONTENTS Chapter 1 - Introduction to. Steady State Simulation •...•..••.••••••..•..•.••.•••••.•...•••••......... I ................... I 1.1 The Steady State Process ................................ .. 1.2 Dynamic Simulation .................... ....................... ............. .......................... 2 1.3 Steady State Simulation Program Features ....................................................... 3 1.3.1 Pure Compon(!nt Data Library ...................... .............. ........... .. ................ 3 1.3.2 Non-Library Components ............................................................................ 4 1.3.3 Thermodynamic Methods ............................................................................. 4 1.3.4 Physical and Transport Properties ........................................... ,.............. :....... 5 1.3.5 Simulated Laboratory Tests....... ............... ............... ............. ....... 5 1.3.6 Unit Operation Calculations ......... .................... .. ................................ 5 1.3.7 Special Flow Sheet Modules........ .................... ................ ....... 6 ..................................................... -/ 1 .3.8 Graphical Interface...................... 1.4 Steady State Simulation Programs.................... .. .......................................... 7 Chapter 2 - Composition of Petroleum Refinery Feed Stocks •..•...........••.................. 10 . 10 2.1 Crude Oil Properties ........................................................ . 2.2 Crude Oil Composition........ .................................. .. ............................... 13 2.3 Crude Oil Assay....... ................................. ....................................... ff ! 2.4 Crude Oil Blending ................................. .. .... 13 .. 14 Chapter 3 - Laboratory Testing of Petmleum Streams ...........................•..••.....•.•..... 16 3.1 True Boiling Point Distillation (TBP) ........................................................... 16 3.2 ASTM 086 Distillation ................................................................................. 17 3.3 ASTM 01160 Distillation ............................................................................. 18 .j 3.4 API Gravity ............................................ . ................................ 19 3.5 Reid Vapor Pressure (R.V.P.) ................. .. ...... ~ ......................... 19 3.6 Chromatographic Simulated Distillations.. ...... . 1:.• .~) 3.7 Flash Point . ......... . 3.8 Pour Point ............................ .. 3.9 Viscosity 'i ........... ............ ...... 20 ................................. 22 ................. 22 ')- .......................... . ................................. _J 3.10 Octanes ............................. . .......................................... 23 3.11 Cetane ................... . ................ '>' L-' Chapter 4 - Developing Petroleum Pseudo-components ............................................ 25 4.1 Pseudo·component Normal Boiling Points ......................................................... 25 4.1.1 Conversion O'fD86 DistillatIons ....................................................... :..... 26 4.1. L I 086 Cracking Corrections .............................................................. 28 5 TABLE OF CONTENTS (continued) 4, I ,2 Conversion of D I 160 Distillations"""",." ""'''''''''''''''''' """,," ." .. " "".". ".29 4.1.3 Conversion of Simulated Distillations ".".""."""".""".".".,,"",, .... ,," ".",29 4.1.4 Selection of TBP Cut-point Ranges .. """"",,, .. ,,.,,,,.,,.,,,,,,,,,,,,,,,,,,,,,,,,,,,,,.,, 31 4,2 Development of Pseudo-component Gravities" ".",,'" ""'''''''''''''''''''''''''''' .33 4,3 Development of Pseudo-component Molecular Weights ""'"'''''''' """"".' .. 35 4.4 Pseudo-component Enthalpies and Critical Propenies "'''''""".""".""""". """ 36 Chapter 5 - Limitations of Petroleum Pseudo-components .•...........••............•...•....... 37 . 5. I Prediction of Laboratory Distillations"""""" " ....... """"""",:.. ,,""",.,,"",, .. ,,'" 37 5.2 Prediction of True Stream Composition '"''".".".".,,''' .... ".,.,"""""',.", ... ,38 5,3 Simulation of Refinery Reactors """ ... "".""."",,.,,'" ",,,,,,,,,.,,,,, ... ,, .. ,,,39 5.4 Simulation of LlIboratory Tests "'''''''''''''''''''''''''''''''''''''''''''''''' "".""".,, " .. ,,", 40 Chapter 6 - Thermodynamics for Petroleum Calculations .............•.••••••...•....•...••..••. 43 6.1 Equilibrium K Values .... _.... __ ................................. _ ......... 43 6,2 Effect of Non-Hydrocarbons on K values",,,,,,,,,,,,.,,,,, """"" ,",,"""'''' ,.""".,44 6.3 H ydrocarbon-Water Systems"",,,,,,,,,,,,, ."." ... " """"""" "".".""".""""".", 4 5 6,4 Enthalpies". ",,"" "".""""""",,,,,,,,,,,,, '" ."."""."." '" """."."."",,"""." ,,46 , 6,5 Recommended Methods for Petroleum Systems .. " .. ,," """"""""""""",,,,, ".46 6,6 Thermodynamic "Rules of Thumb""""""". ":.;~~ .... ".".,"',.,",""',.,' ..... 48 Chapter 7 - Practical Distillation Principles ................................•.•....•.•.................. ".52 7.1 Theoretical Considerations"""" ."., "".,,"" "" ... """."",,""''', 52 7,1.1 Inside-out Distillation Algorithm "".""" ..... ",,. '''''''".""."".".,,'''',,' """" 53 7. 1.2 Column Conventions"."""""" """"".". "" ,,,,,,,,,""''',, """"""."""",,,.,,,, 54 7, I ,3 Initial Solution Estimates" """ """ "" ". "".,,"'" ""," "" """ """""",,, "" "" 56 7.1.4 Non-converged Column Solutions ",,""",,"'''''''' ""'""""""."",,"" """.56 7.2 Simulation of Existing Columns .. """"""", .. 7.2, I Gathering the Information".""""", """"""" 7,2,2 Defining the Separation Zones ".",,""''',,'''''' .. 7,2,3 Translation of Actual trays to Theoretical Trays. 7,2.4 Defining Performance Specifications" ,,,,,,,,,,, 7.2.5 Tray Rating ""''''''''''''''",'' .. "",,",,. """".,,"",,"",,. """~'" 58 "","""""" .... "",,""",, 58 """"""""""",,.,,""",, S9 """"""""" ,," ,,,,,,,,,,64 """""'" """""""",67 """"".". """" 71 7,3 Troubleshooting Actual Columns """""", . 7,3.1 Difficulties Matching Real Column Operations 7,3,2 Diagnosis of Column Operational Problems, "''''''", } '.1 :i , " "","" 72 ,,,,,,72 """"",76 Chapter 8 - Crude Distillation ....... "" ......................................................................... 81 8.1 Crude Distillation Units General Information.".""""". """.""""""""",,.,, "",82 8,1.1 Process Description '''"" ".",,""" ."""."".",,. """"""."."",,. "."""".83 8. 1. 2 Typical Ope, at ions and Control "" ..... """.".,, "."""."""."'" .".,," 87 6 '1 TABLE OF CONTENTS (continued) . C apacny . ........................................ . 8.1.3 Schemes to Increase C rude Processmg . 90 8.1.3.1 Main Column Co·nsiderations .............................................................. 90 8.1.3.2 Furnace Capacity Considerations ........................................................ 93 8.2 Crude Distillation Units: Simulation of Existing Columns .......... __ ........ __ ........... 95 8.2.1 Definition of the Crude OiL.......... . ............................................. 95 8.2.1.1 Crude Assay Data............ ........... ..... . ......... . ............. 95 8.2.1.2 Crude Oil Data from Product Blending ... ..................................... " 98 8.2.2. Collection of Operating and Laboratory Data .......................... . ..... 106 8.2.3 Translation of Actual Trays to Theoretical Trays ................................... 108 8.2.3.1 Main Column Stripping Zone ........................................................... 109 8.2.3.2 Main Column Flash Zone......... . ......................................... 109 8.23.3 Main Column Wash Zone ............ __ . . . . . ...................................... 110 8.2.3.4 Pumparound Zones ....................................................................... 110 8.2.3.5 Side Product Draw Zones.,................ . . . ....................................... 112 8.2.3.6 Top Section of Main Column ........................................................... 112· 8.23.7 Side Stripping Columns .............................................................. 113 8.2.4 Crude Column Overhead System ........................................................... 113 ~.25 Solution Techniques: Inside! Out Column Algorithm ............................... 114 8.2.5.1 Initial Estimates ..................................... ........................................ liS 8.2.5.2 Initial Model Phase................................ ................................... 115 8.2.5.3 Tuning the Model ......................................................................... 116 Chapter 9 - Vacuum Distillation .......•..... _................................................................. 119 9.1 Vacuum Distillation: General Information .......... ........................... ____ ... __ ... 119 9.1.1 Process Description .......... __ .... __ .... __ ..... __ ... . . . ... __ .............. __ .. __ ..... __ .... __ 119 9. I .2 Typical Operations and Control... .. __ .... __ .......... __ ............ __ .... __ .... __ ...... 123 9.2 Vacuum Distillation Units: Simulation of Existing Columns ... __ .. __ ........ __ ..... __ .. 129 9.2.1 Definition of the Topped Crude Oil .. ____ ....... __ ............... ____ .. ____ .... __ .... __ ... 129 9.2.1.1 Crude Assay Data ____ .. __ .................. __ ... .. .............. __ ........... :............ 130 9.2.1.2 Topped Crude Oil Data from Product Blending................................. 130 9 2. I.3 Molecular Weight Estimation .... ............ .............. ...................... . 131 9.2.2 Adjustments to the Topped Crude Oil. ............................................ 131 9.2.3 Collection of Operating and Laboratory Data ................~.. .. ............. 134 9.2.4 Translation of Actual Configuration to Theoretical trays ......................... 135 9.2.4.1 Steam Stripping Zone for Wet Vacuum Units ................................... 136 92.4.2 Boot Cooler Circuits.......... .............. .. ................................. 136 9.2.4.3 Light Gas Oil Zone .............. . ......................... 137 9.2.4.4 Heavy Gas Oil Zone ............. . .. .................... 138 9.2.4.5 Wash Grid and Flash Zone.... .. __ .............. 138 9.2.5 Solution Techniques: Inside/Out Algorithm ....................................... 140 92.5.1 Initial Estimates ................. . ........... ...................... 141 92.5.2 Initial 1--10del Building Phase............. ................ ...141 9.2.5.3 Tuning the Model .............. . . ............................. 145 Chapter 10 - Refinery Reaction Systems .................................................................. 148 7 TABLE OF CONTENTS (continued) 10.1 Reactor Processes- General Information ......................................................... 148 10.1.1 CatalyticCracking ........................... ~ ................................................, .... 150 10.1.2 Hydrocracking and Hydrotreating ........................................................... 153 10.1.2.1 Hydrocracking ................................................................................ 153 10.1.2.2 Hydrotreating ................................................................................. 157 10.1.3 Reforming and Isomerization .................................. ............. ............. 160 10.1.3.1 Catalytic Reforming .....·.................... ............ .160 10.1.3.2 Isomerization ............................................................................. 164 10.1.4 Alkylation and Polymerization .............................. .. .................. 167 10.1.4.1 Alkylation ................................................................................... 167 10.1.4.2 Catalytic Polymerization................................ ............. .. ............ 172 10.1.5 Thermal and Coking ........................................~........ . ......... , ....... 174 10.1.5.1 Visbreaking ............................................................................... 174 10.1.5.2 Coking............................................................... ............. 178 . ............. 181 10.1.6 Hydrogen Plants ......................................... :............... 10.1.7 Ether Processes .................................................................................. 183 10.1.7.1 MTBE Processes ......................................................................... 183 10.1.7.2 TAME Processes........................................... .. ............. 186 10.J Reactor Processes: Simulation Techniques........................... ... .. ..... 188 JO.2.1 Black Box Reactor Mode!... ....................................................... :........ 188 10.2.2 l\·1odified Black Box Reactor ................ ........................... .. ........... 190 10.2.3 Empirical Predictive ReactoL....... ....... ................... .......... .. ........... 193 10.2.4 Free Energy Minimization Reactor (Gibbs) ............ .. ........... 196 10.2.5 Equilibrium Reactor .............................................................................. 198 10.2.6 Stoichiometric Conversion Reactor ................... ............. ....... 200 Chapter 11 - FCC (Fluid Catalytic Cracking) Processes .•....................................... 204 I I I ILl FCC Proces,,,s: Generallnformation ........................................................... 204 11.1.1 Process Description ............................. ................... ............ .. ............... 205 11.1.2 Typical Operations and Control.. .......................................................... 207 11.1.2.1 FCC Reactors .............................................................. .. ..... 208 11.1.2.2 Main Fractionators........................................ .. .............. 208 11.1.2.3 Slurry Strippers............................................... . ........... 211 11.1.2.4 FCC Gasoline Splitters................................... ..~ .... 2!2 11.1.2.5 FCCGasPlants........................................ . .... 212 .. 217 11.2 FCC Processes: Simulation of Existing Units .............. .. . .... 217 11.2.1 Definition of the Reactor Effiuent... ..................... . 11.2.2 Collection of Operating and Laboratory Data ..... . .. 220 11.2.3 Reactor Modeling ......................................... .. . . . . ......... 222 .. .... 223 112.4 Main Fractionator ............................................... . 11.2.4. I Quench (Desuperheating) Zone .................................. . .. .. 224 112A2 Heavy Cycle Oil Zone ................................ .. .... 225 11.243 Light Cycle Oil Zone................................. . .......................... 226 11.244 Heavy Naphtha Zone ....... ...................... . .................... 227 11.2.4. 5 Overhead System ......................................... .. .............. 228 8 TABLE OF CONTENTS (continued) I 1 I ! 11.2.5 Gas Plant Columns ...................... :......................................................... 229 11.2.5.1 Primary Absorber.. ......................................................................... 229 .............. 230 ' er ........................................................... . 11 .. 2 5 ' 2 St npp .. .... 230 11.2.5.3 Secondary Absorber............................ ........... ........... 11.2.5.4 Stabilizer....................................................... . ............. 23) 11.2.5.5 C3! C4 Splitter............................................... ...... ..... .. ....... 23] 11.2.6 Recycle Loops............................................... . .... 232 .. ....... 232 11.2.6.1 Recycle Estimates............................... ........... . 11.2.7 Solution Techniques: Inside! Out Column Algorithm... ...... 233 I 1.2.7. I Initial Estimates: Main Fractionator.. ..... ........... .. ...... 233 I i .2.7.2 Initial Estimates: FCC Gas Plant Columns ...... ...: .... 233 11.2.7.3 Initial Model Phase ..................................................................... 234 11.2.7.4 Tuning the ModeL......................................... . . ....... 234 Chapter 12 - Catalytic Reforming Processes ............................................................ 236 12.1 Catalytic Reforming Processes: General Information ........ .......................... 236 12. I. I Process Description ............................................................................. 237 12.1.2 Typical Operations and Control.......... ........... .. ............................ 239 12.1.3 Catalytic Reformer Reactors....................................... . .......... 241 12.1.4 Reformer Separator Operations............................ ............... . .. ....... 242 12.1.5 Stabilizer Tower Operations .................................... .. ... 242 12.2 Catalytic Reforming Processes: Simulation of Existing Units... .. ............ 243 12.2.1 Definition of the Reactor Effiuent... .................................................... 243 12.2.2 Collection of Operating and Laboratory Data . . . . . . . . . . . . ......... 245 12.2.3 Reactor Modeling............. .............................. .. ...... 246 12.2.4 Stabilizer Modeling .......... ................................... .. ......................... 248 12.2.5 Recycle Loops.......................................................... .. ................ 248 12.2.5.1 Recycle Estimate ...... ... .................................. .. .................... 249 .. .................. 249 12.2.6 CCR Catalyst Systems........................................... 12.2.7 Solution Techniques ........................................................................... 249 12.2.7.1 Blocked Operations ..................................................................... 250 Ch apter 13 - Hydrogen Processes .•.............................•...................................•.......•• 251 ~ 13.1 Hydrotreating Processes: General Information .... . 13. 1.1 Hydrotreating: Process Description ............. .. 13 I 2 Typical Operations and Control.. ............... .. 13 I 3 Hydrotreating Reactors .......... . 13. I .. Separators! Gas Treating .......................... .. ! 3 I 5 Product Stabilizers (Strippers) ...................... . .. ................. 251 .. ...................... 252 .. .......... 253 .............. 255 . ........ 255 .. .... 256 13 2 H\drotr~ating Processes: Simulation of Existing Units....... .................. 256 13.2 I Definition of the Reactor Effillent.................... . .......................... 256 13.22 Collection of Operating and Laboratory Data ............. .. 258 13.2.3 Reactor Modeling............ ............ .. .................. 260 13.24 Modeling Separators! Gas Treating....... .. .................... 262 132.5 Modeling Stabilizer (Stripper) Columns... .............. . ..................... 262 9 ),: - TABLE OF CONTENTS (continued) It 13 .2.6 Recycle I Purge Gas Calculations ......................................................... 263 13.2.6.1 Initial Estimate for Recycle Hydrogen............................................. 264 13.i.7 Solution Techniques ........... ~ ................................................................. : 265 13.2.7: I Blocked Operations..................................................................... 265 13.3 Hydrocracking Processes: General Information .......................................... 266 13.3.1 Hydrocracking: Process Description................. .266 13.3.2 Typical Operations and Contro!........... .. ............................ '267 13.3.3 Hydrocracking Reactors.................. . .......................................... 269 13.3.4- Separators! Gas Treating.......................................................................... 269 13.3.5 Quench Hydrogen ............................................................................ 270 13.3.6 Product Separation ......................................................................... 270 ; 13 A Hydrocracking Processes: Simulation of Existing units ............,.. ............ .. 270 13.4.1 Defmition of the Reactor Effiuent......................... ...............................271 13.4.2 Collection of Operating and Laboratory Data ......................................... 272 13 A.3 Reactor Modeling ................................................................................. 274 13A.3.1 Heat of Reaction ........................................................................... 276 \3 A. 3. '2 Reactor Calculations for the Design Case.. .................... '277 13.4.4 Modeling Separators! Gas Treating......................................... .279 13.4.5 \ - Xem thêm -