Multiphase Reactor Engineering for Clean and Low-Carbon Energy Applications
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Preface xiii
List of Contributors Xv
1 Novel Fluid Catalytic Cracking Processes 1
Jinsen Gao, Chunming Xu, Chunxi Lu Chaohe Yang, Gang Wang, Xingying Lan and Yongmin Zhang
1.1 FCC Process Description 1
1.2 Reaction Process Regulation for the Heavy Oil FCC 3
1.2.1 Technology Background 3
1.2.2 Principle of the Technology 3
1.2.3 Key Fundamental Research 4
1.2.4 Industrial Validation 7
1.3 Advanced Riser Termination Devices for the FCC Processes 10
1.3.1 Introduction 10
1.3.2 General Idea of the Advanced RTD System 11
1.3.3 Development of the External-Riser FCC RTD Systems 12
1.3.4 Development of the Internal-Riser FCC RTDs 15
1.3.5 Conclusions and Perspectives 18
1.4 An MZCC FCC Process 19
1.4.1 Technology Background 19
1.4.2 Reaction Principle for MZCC 19
1.4.3 Design Principle of MZCC Reactor 20
1.4.4 Key Basic Study 23
1.4.5 The Industry Application of MZCC 23
1.4.6 Prospectives 26
1.5 Two-Stage Riser Fluid Catalytic Cracking Process 28
1.5.1 Preface 28
1.5.2 Reaction Mechanism of Heavy Oil in the Riser Reactor 29
1.5.3 The Proposed TSR FCC Process 32
1.5.4 The Industrial Application of the TSR FCC Technology 33
1.5.5 The Development of the TSR FCC Process 33
1.6 FCC Gasoline Upgrading by Reducing Olefins Content Using SRFCC Process 36
1.6.1 Research Background 36
1.6.2 Reaction Principle of Gasoline Upgrading 37
1.6.3 Design and Optimization on the Subsidiary Riser 38
1.6.4 Key Fundamental Researches 38
1.6.5 Industrial Applications of the SRFCC Process 42
1.6.6 Outlook 43
1.7 FCC Process Perspectives 44
References 45
2 Coal Combustion 49
Guangxi Yue, Junfu Lv and Hairui Yang
2.1 Fuel and Combustion Products 49
2.1.1 Composition and Properties of Fuel 49
2.1.2 Analysis of Compositions in the Fuel 50
2.1.3 Calorific Value of Fuel 50
2.1.4 Classifications of Coal 50
2.1.5 Combustion Products and Enthalpy of Flue Gas 51
2.2 Device and Combustion Theory of Gaseous Fuels 52
2.2.1 Ignition of the Gaseous Fuels 52
2.2.2 Diffusion Gas Burner 52
2.2.3 Fully Premixed-Type Gas Burner 53
2.3 Combustion Theory of Solid Fuel 53
2.3.1 The Chemical Reaction Mechanism of Carbon Combustion 54
2.3.2 Carbon Combustion Reaction Process 54
2.4 Grate Firing of Coal 55
2.4.1 Coal Grate Firing Facilities 56
2.5 Coal Combustion in CFB Boiler 57
2.5.1 The Characteristic of Fluidized Bed 57
2.5.2 Combustion Characteristic of CFB Boiler 58
2.5.3 Development of Circulating Fluidized Bed Combustion Technology 58
2.5.4 Comparison Between Bubbling Fluidized bed and Circulating Fluidized Bed 59
2.6 Pulverized Coal Combustion 60
2.6.1 Furnace Type of Pulverized Coal Combustion 61
2.6.2 Circulation Mode of Water Wall 62
2.6.3 Modern Large-Scale Pulverized Coal Combustion Technology 62
2.6.4 The International Development of the Supercritical Pressure Boiler 62
References 63
3 Coal Gasification 65
Qiang Li and Jiansheng Zhang
3.1 Coal Water Slurry 65
3.1.1 The Advantage of CWS 65
3.1.2 The Production of CWS 66
3.1.3 The Atomization of CWS 67
3.2 The Theory of Coal Gasification 70
3.2.1 Overview of Coal Gasification 70
3.2.2 The Main Reaction Processes of Coal Gasification 72
3.2.3 Kinetics of Coal Gasification Reaction 73
3.2.4 The Influencing Factors of Coal Gasification Reaction 77
3.3 Fixed Bed Gasification of Coal 79
3.3.1 The Principle of Fixed Bed Gasification 79
3.3.2 The Classification of Fixed Bed Gasification Technology 81
3.3.3 Typical Fixed Bed Gasification Technologies 81
3.3.4 The Key Equipment for Pressurized Fixed Bed Gasifier 85
3.3.5 The Application and Improvement of Pressurized Fixed Bed Gasifier in China 89
3.4 Fluid Bed Gasification of Coal 90
3.4.1 The Basic Principles of Fluidized Bed Gasification 90
3.4.2 Typical Technology and Structure of Fluidized Bed Gasification 91
3.5 Entrained Flow Gasification of Coal 98
3.5.1 The Principle of Entrained Flow Gasification Technology 98
3.5.2 Typical Entrained Gas Gasification Technologies 101
3.6 Introduction to the Numerical Simulation of Coal Gasification 112
3.6.1 The Numerical Simulation Method of Coal Gasification 112
3.6.2 Coal Gasification Numerical Simulation (CFD) Method 113
References 116
4 New Development in Coal Pyrolysis Reactor 119
Guangwen Xu, Xi Zeng, Jiangze Han and Chuigang Fan
4.1 Introduction 119
4.2 Moving Bed with Internals 121
4.2.1 Laboratory Tests at Kilogram Scale 122
4.2.2 Verification Tests at 100-kg Scale 125
4.2.3 Continuous Pilot Verification 127
4.3 Solid Carrier FB Pyrolysis 129
4.3.1 Fundamental Study 130
4.3.2 Pilot Verification with Air Gasification 136
4.4 Multistage Fluidized Bed Pyrolysis 139
4.4.1 Experimental Apparatus and Method 139
4.4.2 Results and Discussion 141
4.5 Solid Carrier Downer Pyrolysis 145
4.5.1 Experimental Apparatus and Method 146
4.5.2 Results and Discussion 147
4.6 Other Pyrolysis Reactors 149
4.6.1 Solid Heat Carrier Fixed Bed 149
4.6.2 A Few Other New Pyrolysis Reactors 150
4.7 Concluding Remarks 153
Acknowledgments 153
References 153
5 Coal Pyrolysis to Acetylene in Plasma Reactor 155
Binhang Yan and Yi Cheng
5.1 Introduction 155
5.1.1 Background 155
5.1.2 Principles and Features of Thermal Plasma 156
5.1.3 Basic Principles of Coal Pyrolysis in Thermal Plasma 157
5.1.4 Development of Coal Pyrolysis to Acetylene Process 158
5.2 Experimental Study of Coal Pyrolysis to Acetylene 159
5.2.1 Experimental Setup 159
5.2.2 Typical Experimental Results 161
5.3 Thermodynamic Analysis of Coal Pyrolysis to Acetylene 164
5.3.1 Equilibrium Composition with/without Consideration of Solid Carbon 164
5.3.2 Validation of Thermodynamic Equilibrium Predictions 164
5.3.3 Effect of Additional Chemicals on Thermodynamic Equilibrium 165
5.3.4 Key Factors to Determine the Reactor Performance 166
5.3.5 Key Factors to Determine the Reactor Performance 168
5.4 Computational Fluid Dynamics-Assisted Process Analysis and Reactor Design 171
5.4.1 Kinetic Models of Coal Devolatilization 171
5.4.2 Generalized Model of Heat Transfer and Volatiles Evolution Inside Particles 176
5.4.3 Cross-Scale Modeling and Simulation of Coal Pyrolysis to Acetylene 180
5.5 Conclusion and Outlook 183
References 186
6 Multiphase Flow Reactors for Methanol and Dimethyl Ether Production 189
Tiefeng Wang and Jinfu Wang
6.1 Introduction 189
6.1.1 Methanol 189
6.1.2 Dimethyl Ether 189
6.2 Process Description 191
6.2.1 Methanol Synthesis 191
6.2.2 DME Synthesis 192
6.2.3 Reaction Kinetics 195
6.3 Reactor Selection 197
6.3.1 Fixed Bed Reactor 197
6.3.2 Slurry Reactor 198
6.4 Industrial Design and Scale-Up of Fixed Bed Reactor 200
6.4.1 Types of Fixed Bed Reactors 200
6.4.2 Design of Large-Scale Fixed Bed Reactor 201
6.5 Industrial Design and Scale-Up of Slurry Bed Reactor 202
6.5.1 Flow Regime of the Slurry Reactor 202
6.5.2 Hydrodynamics of Slurry Bed Reactor 203
6.5.3 Process Intensification with Internals 203
6.5.4 Scale-Up of Slurry Reactor 206
6.6 Demonstration of Slurry Reactors 213
6.7 Conclusions and Remarks 214
References 215
7 Fischer-Tropsch Processes and Reactors 219
Li Weng and Zhuowu Men
7.1 Introduction to Fischer-Tropsch Processes and Reactors 219
7.1.1 Introduction to Fischer-Tropsch Processes 219
7.1.2 Commercial FT Processes 219
7.1.3 FT Reactors 220
7.1.4 Historical Development of FT SBCR 221
7.1.5 Challenges for FT SBCR 222
7.2 SBCR Transport Phenomena 222
7.2.1 Hydrodynamics Characteristics 222
7.2.2 Mass Transfer 226
7.2.3 Heat Transfer 229
7.3 SBCR Experiment Setup and Results 231
7.3.1 Introduction to SBCR Experiments 231
7.3.2 Cold Mode and Instrumentation 234
7.3.3 Hot Model and Operation 247
7.4 Modeling of SBCR for FT Synthesis Process 249
7.4.1 Introduction 249
7.4.2 Model Discussion 250
7.4.3 Multiscale Analysis 256
7.4.4 Conclusion 258
7.5 Reactor Scale-Up and Engineering Design 259
7.5.1 General Structures of SBCR 259
7.5.2 Internal Equipment 259
7.5.3 Design and Scale-Up Strategies of SBCR 261
Nomenclature 262
References 263
8 Methanol to Lower Olefins and Methanol to Propylene 271
Yao Wang and Fei Wei
8.1 Background 271
8.2 Catalysts 272
8.3 Catalytic Reaction Mechanism 273
8.3.1 HP Mechanism 274
8.3.2 Dual-Cycle Mechanism 274
8.3.3 Complex Reactions 275
8.4 Features of the Catalytic Process 275
8.4.1 Autocatalytic Reactions 275
8.4.2 Deactivation and Regeneration 276
8.4.3 Exothermic Reactions 278
8.5 Multiphase Reactors 278
8.5.1 Fixed Bed Reactor 279
8.5.2 Moving Bed Reactor 280
8.5.3 Fluidized Bed Reactor 281
8.5.4 Parallel or Series Connection Reactors 284
8.6 Industrial Development 286
8.6.1 Commercialization of MTO 286
8.6.2 Commercialization of MTP 288
References 292
9 Rector Technology for Methanol to Aromatics 295
Weizhong Qian and Fei Wei
9.1 Background and Development History 295
9.1.1 The Purpose of Developing Methanol to Aromatics Technology 295
9.1.2 Comparison of MTA with Other Technologies Using Methanol as Feedstock 297
9.2 Chemistry Bases of MTA 298
9.3 Effect of Operating Conditions 300
9.3.1 Effect of Temperature 300
9.3.2 Partial Pressure 302
9.3.3 Space Velocity of Methanol 302
9.3.4 Pressure 302
9.3.5 Deactivation of the Catalyst 303
9.4 Reactor Technology of MTA 304
9.4.1 Choice of MTA Reactor: Fixed Bed or Fluidized Bed 304
9.4.2 MTA in Lab-Scale Fluidized Bed Reactor and the Comparison in Reactors with Different Stages 305
9.4.3 20 kt/a CFB Apparatus for MTA 306
9.4.4 Pilot Plant Test of 30 kt/a FMTA System 306
9.5 Comparison of MTA Reaction Technology with FCC and MTO System 310
References 311
10 Natural Gas Conversion 313
Wisarn Yenjaichon, Farzam Fotovat and John R. Grace
10.1 Introduction 313
10.2 Reforming Reactions 313
10.3 Sulfur and Chloride Removal 314
10.4 Catalysts 314
10.5 Chemical Kinetics 315
10.6 Fixed Bed Reforming Reactors 316
10.7 Shift Conversion Reactors 317
10.7.1 High-Temperature WGS 317
10.7.2 Low-Temperature WGS 317
10.8 Pressure Swing Adsorption 317
10.9 Steam Reforming of Higher Hydrocarbons 318
10.10 Dry (Carbon Dioxide) Reforming 318
10.11 Partial Oxidation (POX) 320
10.11.1 Homogeneous POX 321
10.11.2 Catalytic Partial Oxidation 321
10.12 Autothermal Reforming (ATR) 321
10.13 Tri-Reforming 321
10.14 Other Efforts to Improve SMR 322
10.14.1 Fluidized Beds 323
10.14.2 Permselective Membranes 323
10.14.3 Sorbent-Enhanced Reforming 325
10.15 Conclusions 326
References 326
11 Multiphase Reactors for Biomass Processing and Thermochemical Conversions 331
Xiaotao T. Bi and Mohammad S. Masnadi
11.1 Introduction 331
11.2 Biomass Feedstock Preparation 332
11.2.1 Biomass Drying 332
11.2.2 Biomass Torrefaction Treatment 333
11.3 Biomass Pyrolysis 336
11.3.1 Pyrolysis Principles and Reaction Kinetics 336
11.3.2 Multiphase Reactors for Slow and Fast Pyrolysis 338
11.3.3 Catalytic Pyrolysis of Biomass 342
11.3.4 Biomass-to-Liquid Via Fast Pyrolysis 342
11.4 Biomass Gasification 343
11.4.1 Principles of Biomass Gasification 343
11.4.2 Gasification Reactions Mechanisms and Models 344
11.4.3 Catalytic Gasification of Biomass 347
11.4.4 Multiphase Reactors for Gasification 349
11.4.5 Biomass Gasification Reactor Modeling 355
11.4.6 Downstream Gas Processing 356
11.4.7 Technology Roadmap and Recent Market Developments 357
11.5 Biomass Combustion 359
11.5.1 Principles of Biomass Combustion 359
11.5.2 Reaction Mechanisms and Kinetics 360
11.5.3 Multiphase Reactors for Combustion 361
11.5.4 Advanced Combustion Systems 363
11.5.5 Agglomeration, Fouling, and Corrosion 365
11.5.6 Future Technology Developments 365
11.6 Challenges of Multiphase Reactors for Biomass Processing 366
11.6.1 Fluidization of Irregular Biomass Particles 366
11.6.2 Feeding, Conveying of Biomass 366
11.6.3 Reactor Modeling, Simulation, and Scale-Up 367
11.6.4 Economics of Commercial Biomass Conversion Systems 368
References 369
12 Chemical Looping Technology for Fossil Fuel Conversion with In Situ CO2 Control 377
Liang-Shih Fan, Andrew Tong and Liang Zeng
12.1 Introduction 377
12.1.1 Chemical Looping Concept 377
12.1.2 Historical Development 379
12.2 Oxygen Carrier Material 381
12.2.1 Primary Material Selection 381
12.2.2 Iron-Based Oxygen Carrier Development 382
12.3 Chemical Looping Reactor System Design 384
12.3.1 Thermodynamic Analysis 385
12.3.2 Kinetic Analysis 388
12.3.3 Hydrodynamic Analysis 392
12.4 Chemical Looping Technology Platform 396
12.4.1 Syngas Chemical Looping Process 397
12.4.2 Coal Direct Chemical Looping Process 398
12.4.3 Shale Gas-to-Syngas Process 399
12.5 Conclusion 400
References 401
Index 405
1
NOVEL FLUID CATALYTIC CRACKING PROCESSES
Jinsen Gao, Chunming Xu, Chunxi Lu, Chaohe Yang, Gang Wang, Xingying Lan and Yongmin Zhang
College of Chemical Engineering, China University of Petroleum, Beijing, PR China
Petroleum resources are subjected to a trend toward heavy and low quality in recent years. Then the heavy oil became the main feedstock all over the world. On the basis of the official Manual of First World Heavy Oil Conference in 2006, the recoverable reserve of conventional crude oil is only 1450 × 108 ton, while that of heavy crude oil and oil sand bitumen will reach to 8500 × 108 ton. Furthermore, the highest consumption of crude oil will reach up to 40-45 × 108 ton/annum, among which the heavy oil fractions will take up more than 30 × 108 ton/annum. It has been reported that the proportion of heavy crude oil increased to 17% in 2010 from 11% in 1995 within the petroleum resource supply worldwide. Further, the heavy fraction takes up to more than 50%. As we well knew, the heavy oil fractions cannot be utilized directly. They have to be converted into light transportation fuels, such as gasoline, jet fuel, and diesel, or petrochemical feedstocks, such as ethylene, propylene, benzene, and toluene, which featured with high values. Therefore, the heavy oil upgrading is the key issue to the best utilization of petroleum resources.
The fluid catalytic cracking (FCC) process is one of the most important technologies all over the world among the heavy oil upgrading processes in petroleum refining industries. It was reported that the global refinery capacity was 44.48 × 108 ton/annum up to the end of 2012, while the FCC capacity reached to 7.30 × 108 ton/annum, which took up 16.4% of the total refining capacity worldwide [1], about 45% of all gasoline comes from FCC and ancillary units, such as the alkylation unit. FCC continues to play a predominant role in China as the primary conversion process as well. For many refiners, the FCC unit is the key to profitability in that the successful operation of the unit determines whether or not the refiner can remain competitive in today's market. Up to the end of 2013, China's FCC process capacity reached to 1.5 × 108 ton/annum, making up 30.8% of total refining capacity in China. It provides approximately 30% of the diesel pool and almost 80% of the gasoline pool as a whole to supply the Chinese fuel market.
1.1 FCC PROCESS DESCRIPTION
The FCC process employs a catalyst in the form of very fine particles (average particle size about 60 µm (microns)), which behave as a fluid when aerated with a vapor. The fluidized catalyst is circulated continuously between the reaction zone and the regeneration zone and acts as a vehicle to transfer heat from the regenerator to the oil feed and reactor. Two basic types of FCC units in use today are the "side-by-side" type, where the reactor and regenerator are separate vessels adjacent to each other, and the Orthoflow, or stacked type, where the reactor is mounted on top of the regenerator. Typical FCC unit configurations are shown in Figures 1.1 and 1.2. Although the mechanical configuration of individual FCC units may differ, their common objective is to upgrade low-value feedstock to more valuable products. The main purpose of the unit is to convert high-boiling petroleum fractions called gas oil to high value, high-octane gasoline, and heating oil. Gas oil is the portion of crude oil that commonly boils in the 650+ to 1050+°F (330-550°C) range.
FIGURE 1.1 The basic "side-by-side" type FCC unit configurations.
FIGURE 1.2 The basic Orthoflow or stacked-type FCC unit configurations.
The gas oil feed for the conventional FCC units comes primarily from the atmospheric column, the vacuum tower, and the delayed coker. In addition, a number of refiners blend some atmospheric residue (AR) or vacuum residue (VR) into the feedstocks to be processed in the FCC unit. Table 1.1 presents the typical FCC process product yields on various feedstocks.
TABLE 1.1 The Typical FCC Process Product Yields on Various Feedstocks
Components Daqing VGO, wt% Daqing Atmospheric Residue, wt% Shengli VGO, wt% Fresh feed 100 100 100 Dry gas 1.7 2.4 1.8 LPG 10.0 10.9 9.9 C5 + gasoline 52.6 50.1 52.9 Light cycle oil 27.1 26.7 30.8 Decant oil 4.5 - - Coke 4.1 9.9 4.6 Total 100 100 100The fresh feed and recycle streams are preheated by heat exchangers or a furnace and enter the unit at the base of the feed riser where they are mixed with the hot regenerated catalyst. The heat from the catalyst vaporizes the feed and brings it up to the desired reaction temperature. Average riser reactor temperatures are in the range 900-1000°F (480-540°C), with oil feed temperatures from 500 to 800°F (260-425°C) and regenerator exit temperatures for catalyst from 1200 to 1500°F (650-815°C). The mixture of catalyst and hydrocarbon vapor travels up through the riser reactors. The cracking reactions start when the feed contacts the hot catalyst in the riser inlet and continues until the oil vapors are separated from the catalyst in the riser exit. The hydrocarbon vapors are sent to the main fractionator for separation into liquid and gaseous products.
The catalyst leaving the reactor is called "spent catalyst" and contains hydrocarbons adsorbed on its internal and external surfaces as well as the coke deposited by the cracking. Some of the adsorbed hydrocarbons are removed by steam stripping before the catalyst enters the regenerator. In the regenerator, coke is burned from the catalyst with air. The regenerator temperature and coke burnoff are controlled by varying the air flow rate. The heat of combustion raises the catalyst temperature from 1150 to 1550°F (620-845°C), and most of this heat is transferred by the catalyst to the oil feed in the feed riser. The regenerated catalyst contains 0.01 to 0.4 wt% residual coke depending upon the type of combustion (burning to CO or CO2) in the regenerator.
Since the startup of the first commercial FCC unit in 1942, many improvements have been made in respect to the catalyst, processes, engineering or facilities, and so on. These improvements have enhanced the unit's mechanical reliability and its ability to crack heavier, lower value feedstocks. The FCC has a remarkable history of adapting to continual changes in market demands. In recent years, FCC process including catalysts shows rapid development for the light fuel yield increase, clean transportation fuel production, maximum production of light olefins, and so on. There are some targeted novel processes that appeared actually, such as reaction process regulation for the heavy oil FCC, advanced riser termination devices for the FCC processes, a multi-zone coordinated-controlled (MZCC) FCC process, the two-stage riser FCC process, and FCC gasoline upgrading by reducing olefin content using subsidiary riser FCC (SRFCC) process. All these novel processes have made substantial contributions to China's petroleum refining industry for the improvement of light fuel yield, clean fuel production, and maximum production of light olefin.
1.2 REACTION PROCESS REGULATION FOR THE HEAVY OIL FCC
1.2.1 Technology Background
FCC is one of the core technologies to process the heavy oil efficiently. It could convert the heavy oil into valuable and light oil products and meet the demand for light oil in the market and had the best economic benefit.
In recent years, with the increasing of processing methods in resid-blend and the increasing of the resid-blend ratio, FCC would apply much severe operation conditions (higher temperature, shorter residence time, and larger catalyst-to-oil (C/O) ratio) in order to give thermal shock to the colloid and asphaltene in the residuum oil, and further to crack the residuum oil sufficiently. Universally, this will lead to the overcracking (to some extent) of the raw oil in the FCC riser, which will affect the yield and selectivity of gasoline and diesel. In other words, the highest yields of gasoline and diesel are not in the exit of the FCC riser but in some places of the middle or upper parts of the riser.
One of the efficient measures to deal with this is to terminate the reaction when the yield of gasoline and diesel reaches to the highest value, or to inject reaction-terminating medium into the riser from the point that gasoline and diesel have the highest yield. The application of the reaction-terminating medium could improve the temperature distribution in the FCC riser, control the extent of the catalytic cracking reaction, and optimize the...
