The widespread commercialization of hydraulic fracturing (fracking) combined with horizontal drilling in hydrocarbon containing shale formations has resulted in an enormous increase in natural gas and natural gas liquids (ethane, propane, butane) production, as well as the production of petroleum condensate (light crude oil). Although these processes have been initially commercialized in the US and Canada, other regions of the world will soon (as of 2014) receive the same low cost hydrocarbon economic benefits, either through the importation of natural gas liquids from the US, or hydrocarbon production from their own domestic shale formation reservoirs.
Globally, nearly half of ethylene production is based on light naphtha steam cracking (liquids cracking), where the light naphtha is priced at nearly parity with crude oil ($US 100/bbl in 2014). Natural gas liquids produced via fracking are sold in 2014 at 4–8 $US/MM-Btu , equivalent to an oil price of $US 22-44/bbl, providing an enormous feedstock cost advantage for producing ethylene via steam cracking. The downside is that natural gas liquids steam cracking (gas cracking) produces a smaller amount of the heavier by-products (butadiene, isobutylene, n-butenes, pyrolysis gasoline) used in derivative petrochemicals production.
Where fracking is widespread (in 2014 predominantly in the US and Canada), chemical operating companies have announced significant grass roots projects to build world-scale ethylene steam crackers (gas crackers) that are designed to feed these low cost shale derived feedstocks, in order to capture the cost advantage of natural gas liquids production from shale reservoirs. This report presents current commercial process technology, and the corresponding production economics, for a) producing ethylene via 100% ethane steam cracking, b) producing ethylene via 50:50 ethane:propane steam cracking, and c) producing ethylene via 100% n-butane steam cracking.

1. Introduction 1

Process safety considerations 2

Historical background 2

2. Summary 4

Introduction 4

Process design cases 4

Process safety consideration 5

Ethylene industry status 5

Chemistry and process technology for commercial ethylene production 8

Production economics 14

3. Industry status 15

Steam cracking feedstock 15

Light olefins business status as of 2014 15

Ethylene and propylene product specifications 17

Uses for ethylene 20

Uses for propylene 22

Uses for butylene 23

Uses for C5 olefins 24

Uses for pyrolysis gasoline 24

Global demand for ethylene 24

Global demand for propylene 25

Ethylene global production capacity 27

Propylene global production capacity 29

Ethylene and propylene global capacity utilization 31

Ethylene producers 32

Product pricing 43

4. Chemistry and technology for producing ethylene from NGLs 44

Technology trends and process design features 45

Business objective trends for steam cracking 46

Capacity debottlenecking 47

Operational excellence 48

Overview of steam cracking chemical reactions 49

Thermal cracking chemistry 50

Steam cracking process technology 50

Nonconventional thermal cracking processes 53

      Thermal cracking with partial combustion 53

      The advanced cracking reactor (ACR) process 53

      Ethylene from light crude by Dow’s partial combustion process 54

      Fluidized or circulating bed cracking 54

      The Lurgi sand cracker 54

      BASF’s fluidized coke/flow cracking 55

      The KK process 55

      The Ube process 55

      Quick contact reaction system/thermal regenerative cracking 55

      Shock wave reactor (SWR) 56

Molecular structure of ethylene and propylene 57

Modeling steam cracking reactions 57

      Steam cracking reaction initiation 58

      Reaction propagation 59

      Termination reactions 60

Aromatics formation 61

Over-cracking 62

Pseudo component analysis 62

Steam cracking furnace temperatures 63

Steam cracking operating pressures 66

Steam cracking residence time 67

Hydrogenation of di-olefins 69

Preferred steam cracking feedstock components 71

Dilution steam chemistry 71

Coke formation chemistry 72

Green oil chemistry 75

Red oil chemistry 76

Acid gas chemistry 77

Advances in pyrolysis furnace design 77

      Firebox design 78

      Burner arrangement 79

      Low NOx burners 79

      Refractory coating 80

      Modeling applications 80

Radiant coil design 81

Tube metallurgy 83

Coke reduction 84

      Mechanisms of coke formation 85

Catalytic coking 85

Pyrolytic (thermal) coking 86

Aerosol coking (polyaromatic condensation) 86

Antifoulant additives 86

Permanent surface coatings 88

Other surface treatments 89

Transfer line exchangers 90

Non-conventional ethylene production technologies 91

      SUPERFLEX process 91

Lurgi Propylur process 92

      Dehydration of bio-based ethanol 93

Siluria oxidative coupling process using methane feedstock 93

5. Steam cracker process design basis 95

Introduction 95

Design conditions 95

Site location 96

Facility site basis 96

      Cost basis 96

      Capital investment 97

      Construction capital cost index 98

      Project construction timing 99

      Production costs 99

      Feedstock, product and energy pricing 100

      Effect of operating level on production costs 100

      Ethylene plant capacity utilization 101

      Available utilities 101

      Rotating equipment drivers 102

      Continuous versus batch processing 102

      Site wide considerations 102

      Production capacity 102

      By-product recycle 103

      Flexible feedstock furnaces 103

      Feedstock specifications 103

      Feedstock NGL contaminants requiring removal 105

      Ethane feed specifications 105

      Ethane:propane mixed feed specifications 106

      Propane feed specifications 107

      Normal butane feed specifications 109

      Sulfur addition 109

      Steam to hydrocarbon ratio 110

      Contaminant removal 110

      Overall steam cracking furnace yields 110

      Feed and product storage 114

      Product run down tankage 114

      Ethylene and propylene product tankage 114

      Di-Olefin conversion 114

      Safety considerations 115

      Product physical properties 115

      Capacity debottlenecking 117

      Manufacturing excellence 118

      Design philosophy 118

      Design priorities 119

      Process safety 119

      Equipment reliability 120

      Environmental conformance 120

      Flexibility for economic optimization 121

      Ease of operations & maintenance 121

      Return on investment criteria 122

      Security and vulnerability analysis 122

      HAZOP/Safety considerations 123

      Plant layout for process safety 127

      Environmental design standards & facilities 133

      Noise 133

      Fuel gas sulfur content 133

      Major project emission sources 134

      Incineration 135

      Atmospheric emissions 136

      Flare gas management strategy 137

      Anti-coking additives 139

      Continuous anti-coking chemical additives 141

      Hard coated cracking tubes 142

      Cracking furnace design basis 143

      Furnace tube metallurgy 143

      Principle NGL cracker design features 144

      Front end de-ethanizer distillation sequence 145

      4 Stage (rather than 5 Stage) cracked gas compression 145

      Process refrigeration 145

      Gas turbine drivers for the cracked gas compressor 145

      Reactive distillation for di-olefin conversion 146

      Hydrogen purification 147

      Vapor recompression for the propylene splitter 148

      Energy recovery via turbo expander 148

      Raising 120 bar superheated steam pressure in the transfer line exchangers 148

      Ubiquitous on-line gas chromatograph (GC) analyzers 148

      Computer control systems incorporating open field bus architectures and on-line economic optimizer 149

      Integrated cogeneration 150

      Redundant critical instrument sensors will be employed using 3-way voting logic 151

      Provide rotating machine condition monitoring instrumentation 151

      Extensive use of inline particulate filters and emulsion coalescers 152

      Online cracked gas compressor washing 152

      Engineering and design standards 152

      Ethylene and propylene product specifications 153

      By-product specifications 154

      Real estate requirements 156

      Regulatory environment and EHS standards 156

      Construction methodology 156

      Offsite facilities 157

      Black start capability 157

      Process control philosophy 158

6. Ethylene technology licensor offerings 159

      KBR SCORE technology 159

      KBR SCORE process 159

      KBR pyrolysis furnace technology 160

      KBR Olefins purification technology 164

      Chicago Bridge and Iron (CB&I)/Lummus technology 167

      Conventional Lummus process 168

      Ethane only steam cracking 169

      Advanced Lummus steam cracking process 169

      Lummus conventional olefins recovery technology 171

      Lummus metathesis technology 173

      Stone & Webster (acquired by Technip in 2012) 175

      Stone & Webster process description 177

      Linde AG ethylene process technology 182

      Linde value cracking 190

      Technip licensed ethylene process 190

      Technip commercial experience mid-2014 191

      Technip steam cracking process sequence 191

      Technip pyrolysis furnace technology 194

      Technip radiant oil design options 195

      Technip SPYRO process simulation software 195

      Technip olefins recovery technology 197

      Sinopec ethylene process technology 197

      Feedstock pre-treatment to remove mercury, arsenic, and lead 197

      Drying cracked pyrolysis furnace gas 200

7. Ethylene via 100% ethane steam cracking 201

Input-output diagram 201

      Block flow diagram 202

      Drawing nomenclature 204

      US EPA Greenhouse gas application data 204

      Design basis table 212

      Process description and flow diagrams 213

      Section 300 – Cracked gas compression and acid gas removal 218

      Section 400 – Cryogenic refrigeration and cold box 219

      Section 500 – Hydrogen purification 223

      Section 600 - Cryogenic distillation 223

8. Ethylene via 50:50 ethane:propane steam cracking 233

Introduction 233

Design basis 233

      Process description: Section 700 – Propylene purification 234

Stream by stream material balance 234

Equipment list with duty specifications 236

Total fixed capital cost estimate 240

Variable production cost estimate 242

Total production cost estimate 243

9. Ethylene via normal butane steam cracking 246

Design basis 246

Overall yield pattern 246

Once through process yields 247

Equipment list with duty specifications 249

Total fixed capital cost estimate 253

Variable production cost estimate 255

Total production cost estimate 255

Appendix A: Stream by stream material balances 258

Appendix B: Patent summary tables 281

Appendix C: References 306

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