甲胺生产节能工艺的研究

Study on energy saving for methylamine processing

甲胺是重要的有机化工原料,我国甲胺生产能耗一直远远高于国际水平。为了开发甲胺生产节能流程,全流程模拟某厂甲醇气相胺化法的甲胺工艺,逐个分析系统各个用能设备的能量利用情况,找出节能的关键环节,分3个步骤改进节能,首先在合成系统合理回收能量,提高装置的能量利用效率,能耗下降37%;再模拟优化分离系统5个精馏塔,找到最佳的操作参数,能耗下降20%;最后通过热量集成进一步节能18%。优化后的节能新工艺比原来节能36%,中压蒸汽、高压蒸汽、循环水消耗量降幅分别达50%、22%、40%,节省操作费用464万元/a,只增加少量设备投资,节能效果和经济效益显著。甲胺产品质量较优化前有提高。新的节能工艺为甲醇新装置的设计和原有装置的改造提供有益的参考。

The energy consumption of methylamine production in China is much higher than developed country. It is very necessary to explore energy saving technology of methylamine processing which is mainly composed of two parts, i. e, reaction and distillation. This catalytic reaction is a gas amination of methanol with ammonia to methylamine which consists of monomethylamine, dimethylamine and trimethylamine, among them the trimethylamiue selectivity is highest but the dimethylamine demand quantity is largest about 80%. Based on the process simulation and analysis of methylamine production, the key units that consume more energy than others are identified and analyzed separately. The improvement process includes three steps： firstly, the extra heat produced by reaction are used rational to heat the feed stock sufficiently which improves the energy utilization efficiency of process units and recovers effectively the available waste energy so as to reduce energy by 37% ; secondly, optimization and simulation of five-column continuous distillation are performed with Pro-II software to find the optimal operating parameters of each column so as to reduce energy by 20% ; finally, heat integration technology is carried out to reduce energy by 18% further. The new process could save energy by 36%, decrease the consumption of 1.0MPa steam, 2. 3MPa steam and recycle water by 50%, 22%, 40% respectively, improve product quality, save operating cost 4. 64 million Yuan per year with a less equipment investment by developing the potential capacity of the existing equipment.The result indicates it is effective in energy-saving and economic profits. The study offers a significant solution for designing new equipment and expansion revamp of methylamine production.