Revamp From Two-step To One-step Rectisol Wash Process

At present, the chemical industry in our country is developing rapidly, the gas product related to the industry is gradually increasing, so the air pollution becomes more and more serious. Human society's awareness of harmonious development between man and nature is gradually increasing, the world organization of environmental protection pay more attention to the exhaust emissions, such as CO2 which can result in greenhouse effect, so the treatment of acidic gas became the focus. In addition, with the influence of the world energy crisis, in order to make full use of energy, gas purification is particularly important especially in the acid gas purification of raw gas. In all the acid gas absorption and purification methods low temperature methanol wash is the most effective method, in the low temperature methanol wash the methanol consumption is small, the absorptive capacity is strong, the thermal stability is good, so it is widely used in acidic gas purification process.There are two kinds of typical process of rectisol, one is two-step process represented by Lurgi company, another is one-step process represented by Linde company. The difference between two processes is that desulfurization and decarbonization happen at same time in one-step rectisol process but two times in two-step rectisol. Desulphurization is the procedure to prevent the catalyst from sulfur contamination. Now the new sulfur-prevented catalyst has been developed, I do the revamp from two-step to one-step in this paper based on feed conditions change of factory. The main purpose of revamp is enhancing the rectisol system to cater to the changing market environment and market demand, until now few people has done the revamp.Two-step rectisol process is simulated through software, compared simulation results and real factory results, find out the best tower parameters, for example, temperature, pressure, numbers of tower plates, reflux ratio, feed location and physical method by adjusting unit parameters. Then according to the feed conditions change of the new raw material gas, with the premise of the minimum of original equipment change, adjust the tower and the pipeline, under the circumstances of simulation results meeting the new process purification standard, choose the plan that needs the lowest cost, that is the optimal one-step process, verifying the rationality and feasibility of the revamp.Above provides a technical scheme and technical support for factory.