The Retrofit Of Methylamine Plant For Energy Conservation And Consumption Reduction

The production capacity of methylamine plant in Hualu-Hengsheng Chemical Co.,Ltd.is in the first place on a nation wide scale.It has trained a large number of chemical engineers and also created huge benefits for the company.In recent years,the rising in price of raw materials,such as coal,electricity,steam,increases the methylamine production cost and reduces the profits.This situation makes the company face a severe pressure to survive.Thus,the retrofit of methylamine plant for energy conservation and consumption reduction is a inevitable choice.Hualu-Hengsheng Chemical Co.,Ltd.has three methylamine production plants.According to the comprehensive analysis and comparison,the steam consumption of 4#methylamine plant is the highest.In the normal process of production,When the TMA is not limited,the steam consumption of mixed amine is 5.5 t/t.When the TMA is limited,the steam consumption of mixed amine is 7.0 t/t,folded into 8.0 t/t of the DMA steam consumption.Compared to the peer companies both at home and abroad,the steam consumption is higher and can not take any cost advantage.Thus,the retrofit of methylamine plant for energy conservation and consumption reduction is imperative.After intensive research,analysis and comparison,we find the following main reason of the high consumption in the plant.The rectification effect of 1#tower,2#tower and 3#tower in 4#methylamine plant is poor,which causes the poor quality of product and the high steam consumption.Besides,the heat energy of 4#methylamine plant can not be fully utilized.This paper takes the following measures to achieve the purpose of energy conservation and consumption reduction.Increased the height of the 1#tower and replaced the packing within rectifying and stripping sections to improve the distillation separation effect of 1#tower,reduce the content of mixed amine in extract product of the top of tower and the content of NH3 in tower kettle discharging and also reduce the steam consumption;changed the tray of 2#tower plate to the new float valve tray and removed the bottom of tray downcomer plate to improve the liquid circulation ability and the rectification effect of 2#tower and also reduce the content of MMA and DMA in the TMA of the top of tower;changed the cylinder of distillation section in 3#tower to a double overflow tray and added an efficient structured packing on the top of tower to improve the separation effect of 3#tower,improve the purity of the MMA and DMA and reduce the content of methanol at the top of tower;utilized the kettle wastewater of wastewater purification tower to preheat raw material methanol and the condensate of steam to heat the gas ammonia and the feedstock in the 1#tower.Optimized the use of the waste heat in the 4#methylamine plant and reduced the steam consumption.Through the optimization of the 1#tower,2#tower,3#tower in 4#methylamine plant and fully recycle use of the heat of synthesis reaction,condensation liquid and waste,the production capacity has been obviously improved and the steam consumption has been greatly reduced.This reaches the advanced level of this industry.Furthermore,this meets the needs of three kinds of methylamine products in the domestic and international market and reaches the high level of the product quality and energy consumption in line with international standards.