Simulation Of Rectisol Process Of Coal-to-liquids Technology And Energy Conservation Transformation

The indirect liquefaction method of coal-to-liquids technology need to convert the coal into gas before feed it into the unit of catalytic hydrogenation. For redusing the corrosion and catalyst poisoning, we need to removing the acid impurity of the raw gas.Among a number of acidic gas purification technologies, rectisol is a mature acidic gas purification technology, and the process unit can separate the CO2and the sulfer components. We can get purifying gas that meet the technological requirements through using methanol around50℃to absorb the impurity in feed gas, in the same time, we can get the high purity CO2to be the by-products through the prcoess of desorbing and regeneration by the follow-up process units.We are talking about the rectisol of8-tower process in this paper, the process can get the purifying gas which has removed all the sulfer impurity and has reduced the CO2content lower to2%, and the mole fraction of the by-product, CO2can reach more than98%. It is an advanced unit of acidic gas purification.But in the actural production of the rectisol in this plant, we found that the energy consumption is too high in normal condition, the cost of production need to be reduced by energy conservationg transformation. First, in this paper we use a software of Aspen Plus to simulate the process of rectisol, choose a property method of PSRK and compare the simulation results of thionizer, tower of decarburization, CO2flash tower, H2S flash tower, H2S evaporating tower, thermal regeneration tower, exhaust gas scrubber and methanol water separator, and the actual meatured value. We can confirm the right model of simulation of the original process.We found the reason of high energy consumption of the original process and the solution. The main reason is the lager loss of refrigeration capacity, give a big workload to the chillers. If we want to achieve the aim of energy conservation, the main direction of work is to increase the heat transfer between flows and reduce the chillers’workload.