This report presents a technical and economic evaluation of three technologies used in the production of benzene, toluene, and xylenes (BTX). The feedstocks for the BTX processes are C3-C4 range aliphatic/olefinic hydrocarbons. PEP Reports 129A, 129B, and 182B (published in 1996, 2006, and 2008, respectively), covered BTX technologies based on the catalytic reforming of light naphtha or pyrolysis gasoline.
The current report, however, focuses on BTX produced from liquefied petroleum gas (LPG) as individual, refined products that serve as feedstocks for several other commercially important derivative chemicals. Hence, the starting materials covered in this report differ from those in previous reports covering aromatics.
From the perspective of feedstocks, LPG has a cost advantage over light naphtha-range hydrocarbons. However, many LPG production regions are remote, resulting in high transportation costs, leading LPG producers to look for ways to convert LPG (or C3-C4-rich streams) into more valuable products that are in higher demand, such as BTX.The three technologies analyzed in this report are UOP-BP Cyclar technology, SINOPEC Luoyang GTA technology, and Mitsubishi-Chiyoda Z-Forming technology.
UOP-BP’s Cyclar technology is based on a bifunctional catalyst consisting of a metal (gallium) modified zeolite (ZSM-5) base material. The highlight of this process is the proprietary continuous catalyst regeneration system (CCR system), a feature used by UOP for the last 40 years. Another important feature of the process is the type of reforming system, which consists of a series of vertically stacked reactors in which catalyst flows down under gravity in the form of a dense medium and reactants flow through the catalyst bed in a radial direction. Operating conditions are 896-1,022°F (480-550°C) at <100 psia. BTX yield can be up to 60-65 wt%. Feed to process is LPG or light naphtha. For BTX separation, only simple distillation (SD) is used.
SINOPEC Luoyang’s GTA technology is also based on a bifunctional catalyst consisting of a metal (undisclosed, but likely zinc or gallium) modified zeolite (ZSM-5) base material. The reforming reactors are of an adiabatic, fixed-bed type. Operating conditions are 860-986°F (460-530°C) at <70 psia. BTX yield can be up to 55-60 wt%. Feed to process is C4-rich olefinic streams. For BTX separation, only SD is used.
Mitsubishi-Chiyoda’s Z-Forming technology is also based on a bifunctional catalyst consisting of a metal (undisclosed, but likely zinc) modified zeolite (ZSM-5) base material. The reforming reactors are of an adiabatic, fixed-bed type. Operating conditions are 932-1,112°F (500-600°C) at <100 psia. BTX yield can be up to 55-58 wt%. Feed to process is LPG or light naphtha. For BTX separation, only SD is used.

1. Introduction 1

2. Summary 2

Feedstocks 3

Reaction conditions 4

Catalysts 4

Design conditions 5

Light-naphtha-based processes 7

Process economics 8

Overall economic conclusion for the Cyclar process 9

Overall economic conclusion for the GTA process 9

Overall economic conclusion for the Z-Forming process 10

3. Industry status 13

Capacity, production and consumption 13

      Benzene 13

      Toluene 17

      Xylenes (mixed) 22

4. Technical review 26

Catalysts 26

Monofunctional catalysts 27

Dual-function catalysts 27

Feedstocks 28

Reaction conditions/parameters 30

Selectivity and conversion 30

Staged aromatization 32

Reactors 37

5. UOP process for BTX production by catalytic reforming of LPG 39

Process description 39

Process discussion 49

      Process design choices 49

      Feedstock 49

      Conversion parameters 50

      Reformer heaters sizing 50

      Fired-heaters fuel consumption efficiency 51

      Product recovery 51

      Refrigeration 51

      Materials of construction 51

Cost estimates 51

      Fixed capital costs 52

      Production costs 52

      Overall economic conclusion 52

6. SINOPEC Luoyang GTA process for BTX production by catalytic reforming of C4 raffinate-II 58

Process description 58

Process discussion 67

      Process design choices 67

      Catalyst 67

      Reactor 68

      Feedstock 68

      Product recovery 68

      Product spectrum 68

      Refrigeration 68

      Materials of construction 69

Cost estimates 69

      Fixed capital costs 69

      Production costs 70

      Overall economic conclusion 70

7. Mitsubishi-Chiyoda Z-Forming process for BTX production by catalytic reforming of C4 (butanes) 75

Process description 76

Process discussion 85

      Process design choices 85

      Catalyst 85

      Reactor 85

      Feedstock 86

      Product recovery 86

      Product spectrum 86

      Refrigeration 87

      Materials of construction 87

Cost estimates 87

      Fixed capital costs 87

      Production costs 88

      Overall economic conclusion 88

Appendix A: Patent summary tables 93

Appendix B: Design cost bases 109

Design conditions 109

Cost bases 109

Capital investment 109

Production costs 110

Appendix C: Cited references 112

Appendix D: Patent references by company 113

Appendix E: Process flow diagrams 114

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