Technology

Introduction

Among the processes such as adiabatic dehydrogenation, isothermal dehydrogenation and dehydrogenation-selective oxidation, the vacuum adiabatic dehydrogenation of ethylbenzene (EB) is the most popular and mature process to produce Styrene Monomer (SM). The S-SMT™ process is a vacuum adiabatic dehydrogenation of EB to produce SM.

Features of Technology

The S-SMT™ process is the commercially-proven and proprietary technology for dehydrogenation of EB over GS™ series catalysts in the presence of steam. This process exhibits good reliability, reasonable operation flexibility, low EB consumption per unit of SM production. In particular, the interstage reheater is incorporated into the two-stage axial-radial reactors system. The utilization ratio for the reactor space and the catalyst is improved by using fluid dynamics technology to optimize designs of collection and branch flows for the uniform fluid distribution and to meet the reasonable pressure drop requirement for a vacuum adiabatic reaction.

The dehydrogenated mixture is fractioned by using the energy-saving distillation process, which substantially reduces the plant energy consumption. Because the styrene product is heated only twice in the EB/SM splitter and styrene column, the styrene loss caused by its polymerization is reduced. In addition, the absorber system operating at lower temperatures is conducive to the recovery of aromatics in vent gas, and the flash drum operated under vacuum is used for further recovery of the styrene in the bottoms. In general, the waste emission, i.e. the environment pollution, is controlled at very low level.

Besides, GS™ series catalysts also play an important role in S-SMT™ process. They offer high EB conversion along with excellent styrene selectivity, excellent mechanical strength, low pressure drop, long service life at low steam to hydrocarbon ratio. GS™ series catalysts not only have exhibited excellent performance in an S-SMT™ process unit, but also have been successfully used as a drop-in catalyst in many other company-licensed process units in China.

Services

Licensing scope and technical services are provided by China Petrochemical Technology Co., Ltd. (SINOPEC TECH).

References

1. Document uploaded on 5^th July 2015 on Yumpu, S-SMT Technology for Production of Styrene by Sinopectech.com.
2. SINOPEC, 6^th Dec 2022, Products & Service, Petrochemical, S-SMT™ Technology for Production of Styrene by Ethylbenzene Dehydrogenation.