The Study On Process Simulation And Optimization Improvement Scheme Of Rectisol Equipment Of On A Plant

Methanol is the most representative product of coal chemicals in China.The methanol synthesis gas produced from coal contains not only CO,H₂ and other effective gases,but also various sulfides and CO₂.These acid gases will corrode the equipment and cause catalyst poisoning and deactivation,so the synthesis gas must be decarburized and desulfurized before synthesis.Low temperature methanol washing technology is widely used in the purification of methanol synthesis gas from coal.It is a typical physical absorption process.The selectivity of low temperature methanol to acid gas is very high.The recovery of CO₂ and sulfide can be achieved by using methanol.Firstly,this paper takes a low temperature methanol washing process as the research object,simulates the process with Aspen Plus simulation software,and analyzes the key logistics of C1 tower,C2 tower and C3 tower successively.Based on the step-by-step simulation of key equipment,the whole process of low-temperature methanol washing process is further simulated.The simulation data show that the mole fraction of purified gas CO₂ is less than4%,and the concentration of sulfide is close to 0%,indicating that the gas has met the conditions of methanol synthesis and can be used for methanol synthesis.In addition,the exhaust gas can also meet the requirements of air evacuation,and can be discharged directly after heat recovery.These results further verify that the unit module and physical property method selected in the simulation process is reasonable.Secondly,according to the requirements of production expansion,the simulation optimization of the process is studied.Starting from the characteristics of low-temperature methanol washing process,according to the principle of methanol absorption,in the case of increasing the treatment gas,the amount of methanol absorbent is not increased,but from strengthening the regeneration degree of methanol and cooling,respectively,a nitrogen stripper and a utility heat exchanger are added to achieve the improvement of methanol absorption capacity,and then to achieve the purpose of expanding production.The results show that the above transformation scheme is feasible and has practical guiding effect on the expansion and transformation of enterprises.