The Design Of H₂S Concentration Process And The Simulation Of Rectisol Process

Rectisol process with low-temperature methanol as the absorbent to selectively remove the acid gas components of the raw material gas has been considered as a highly-efficient and energy-saving acidic gas purification technology. With the rapid development of ammonia synthesis industry, natural gas desulfurization and other chemical industries, energy conservation and environmental protection have become a worldwide problem. Consequently. the study of gas purification technology has become one of the most important clean energy technologies.In this work, a convincible rectisol process is designed and simulated according to the raw material conditions provided by a factory. The composition of the obtained gas after purification through this process meets the product requirement, and the waste water and gas meet the emission standards. The conditions of the feed gas and the purification requirements provided by the factory are as follow:1.The content of H2S in the raw gas is relatively low, and there is no requirement for CO2 recovery. Therefore, adjustment of the CO2 desorption tower and H2S concentration tower in the traditional process is necessary, and a new process is to be designed.2. The raw gas contains much water and organic sulfur compounds such as thiophene. methyl mercaptan and carbonyl sulfide, thus it requires a pre-washing section to remove these impurities. In addition, an additional extraction system is required to discharge the organic sulfur compounds from the system. After designing and debugging of a series of operating parameters, the new process is able to satisfy the requirement of purification and separation.In this paper, the commercial simulation software of Aspen Plus is adopted for designing and simulation of the new process. The process is optimized by the sensitivity analysis, and then the process design is completed. Subsequently, the pinch analysis of the heat transfer equipment in this process is carried out to optimize the heat transfer network matching. Then the process of design and simulation is finished. The purified gas has met all the requirements of purification, namely the concentration of CO2. the total sulfide concentration and the concentration of H2O are no more than 0.3%, 100ppb and 10ppm, respectively. The concentration of H2S in the acid gas is required to be larger than 25%. The content of methanol in wastewater is no more than 0.01% wt. The content of methanol in vented tail gas is no more than 135ppm.The total content of H2S and COS in vented tail gas is below 10ppm. This work provides a reliable theoretical basis for the design and construction of a factory.