The Design Of Rectisol Process With Low-pressure Feed Gas

The gas after the coal gasification contains acid gases such as CO2, H2S, COS besides CO, H2, who will cause catalyst poisoning in following ammonia and methanol synthesis process, etc. Therefore, these gases need to be purified and Rectisol can do this. At low temperature, since the solubility of acid gases in methanol is larger than other gases, the Rectisol process can achieve the removal of acid gases using low-temperature methanol.The present work designed a Rectisol process to purify the raw material gas that provided by a factory. Different from general raw gas, it has lower pressure and contains a number of styrene. For this case, a CO2 auxiliary desorption column was incorporated in Rectisol process to resolve the problem of CO2 recovery. Meanwhile, a prewash segment and an extractor were set also to complete separation and recovery of styrene on the basis of the general Rectisol process.In Aspen Plus software, the property method PSRK was selected, and design spec and sensitivity analysis tools were used to simulate and analyze the parameters of the various facilities. The parameters were optimized not only to meet the technical requirements but also to make the investment and operating costs as less as possible. After the process simulation, the heat exchanger network (HEN) was built and pinch technology method was applied to recovery energy. At last, the full process simulation was performed successfully, the new process satisfies the purification requirement and its consumption is reasonable, which process broadens the application range of Rectisol process.