This report covers the technology and costs of manufacturing ethylene from naphtha via steam cracking. The three process configurations presented are:
• Front-end demethanizer
• Front-end depropanizer
• Front-end depropanizer with a gas turbine driver for the cracked gas compressor
For each process configuration, we have examined four design cases:
• Wide range naphtha feed for maximum propylene yield
• Wide range naphtha feed for maximum ethylene yield
• Light virgin naphtha feed for maximum propylene yield
• Light virgin naphtha feed for maximum ethylene yield
Each of the process configurations has been sized to allow production under all four design cases. We present capital cost estimates for each of the three process configurations. We also present operating cost estimates for all twelve of the process configuration/design case pairs.
Our goal in this project has been to present a set of designs that represent “typical” current practice. This report is intended to illustrate ethylene production economics as it is commercially practiced now, in late 2014.

1. Introduction 1

2. Summary 2

Front-end demethanizer 2

Front-end depropanizer 3

Front-end depropanizer with gas turbine driver 3

Process economics 4

3. Industry status 8

Characteristics of the market 9

4. Technology review 10

Cracking furnace yields 10

A brief survey of the literature 12

5. Front-end demethanizer 14

Process description 14

      Pyrolysis and quench 33

      Compression and drying 33

      Subcooling and separation 34

      Product separation 34

      Refrigeration 35

      Steam distribution 35

Process discussion 35

Cost estimates 37

      Capital costs 37

      Production costs 37

6. Front-end depropanizer 46

Process description 46

      Pyrolysis and quench 65

      Compression, drying, depropanizer 65

      Subcooling and separation 66

      Product separation 66

      Refrigeration 67

      Steam distribution 67

Process discussion 67

      Two-stage front-end depropanizer 68

Cost estimates 69

      Capital costs 69

      Production costs 69

7. Front-end depropanizer with gas turbine driver 80

Process description 80

      Pyrolysis and quench 100

      Compression, drying, depropanizer 101

      Subcooling and separation 110

      Product separation 110

      Refrigeration 110

      Steam distribution 111

      Gas turbine and HRSG 111

Process discussion 111

      Two-stage front-end depropanizer 112

      Gas turbine 113

Cost estimates 113

      Capital costs 113

      Production costs 113

Appendix A: Patent summaries 115

Appendix B: Design and cost bases 119

Design conditions 119

Cost bases 119

Capital investment 119

Production costs 120

      Effect of operating level on production costs 121

Appendix C: Reference citations 122

Appendix D: Patent references by assignee 125

Appendix E: Process Flow Diagrams 126

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