Energy, exergy, exergoeconomic and sensitivity analyses of modified Claus process in a gas refinery sulfur recovery unit

Abstract

In this study, the sulfur recovery unit based on the modified Claus process with the split flow is simulated and the results are validated with South Pars gas refinery data. Since optimum energy consumption is essential for community development, exergoeconomic and sensitivity analyses are conducted to prevent waste production and increase energy efficiency in this unit. Energy and exergy analyses are performed to identify the equipment with low exergy efficiency and calculate their exergy destruction extent. Reaction furnace with 4178.8 kW exergy destruction has the highest rate, and then waste heat boiler and P-7 pump are placed. After the pumps, the heat exchangers have the lowest exergy efficiency so that the acid gas preheater with the value of 60% has the lowest one. All equipment investment and operating and maintenance cost calculations are carried out so that the largest cost is related to the hydrolyzing Claus bed that followed by waste heat boiler and P-7 pump. Then equipment exergoeconomic parameters such as exergoeconomic factor, cost rate of exergy destruction and relative cost difference are obtained. The lowest exergoeconomic factor among the process equipment is related to reaction furnace and second condenser with the values of 0.26% and 0.86%, respectively. The maximum exergoeconomic factor is 94% which is attributed to compressors. The reaction furnace with 4706.16 ($/h) and waste heat boiler with 4629.89 ($/h) have the highest cost rate of exergy destruction and CMPR-5 compressor with 0.2451 ($/h) has the lowest cost rate. Finally, considering some of the functional and economic parameters in the sensitivity analysis procedure, the influence of changing these variables on exergoeconomic parameters have been investigated.