Investigating efficiency improvement in sulfur recovery unit using process simulation and numerical modeling

Farhad Fazlollahi,Sajjad Asadizadeh,Majid Sarkari,Milad Ahmadi Khoshooei,Mohammad Reza Sardashti Birjandi

doi:10.2516/ogst/2020093

Abstract

Hydrogen sulfide exists mostly as a detrimental byproduct in the gas processing units as well as refineries, and it must be eliminated from natural gas streams. In a Sulfur Recovery Unit (SRU), hydrogen sulfide is converted into the elemental sulfur during the modified Claus process. Efficiency of sulfur recovery units significantly depends on the reaction furnace temperature. In this work, the effect of oxygen and acid gas enrichment on the reaction furnace temperature and accordingly on sulfur recovery is studied, using both numerical modeling and process simulation. Then, simulation and numerical model are benchmarked against the experimental data of an SRU unit. The validated model provides spotlight on optimizing the upstream sulfur removal unit as well as the oxygen purification process. Two cases of acid gas streams with low and high H2S content, 30% and 50%, are studied to investigate the effect of operating parameters on the overall recovery. Finally, average errors of the models are presented. According to the absolute difference with experimental values, the developed numerical model shows great potential for accurately estimating overall efficiency of the recovery unit.

Highlights

Due to stringent environmental constraints, after the removal of H2S from fossil fuels, it should not be released to atmosphere
We present a Claus process simulation as well as numerical modeling for evaluation of air and acid gas enrichment that potentially affects the reaction furnace temperature and H2S conversion efficiency in sulfur recovery unit that process both low and high hydrogen sulfide contents
The results show that oxygen enrichment will have an important effect on the reaction furnace temperature for acid gas streams with different

Summary

Introduction

Due to stringent environmental constraints, after the removal of H2S from fossil fuels, it should not be released to atmosphere. The injection of acid gas streams which are rich is hydrogen sulfide is proposed to avoid the release of this harmful component into atmosphere. This method is potentially challenging due to the toxic and corrosive nature of H2S [6].

Methods

Results

Conclusion