浆态床一步法合成二甲醚能耗分析与优化

发布时间：2018-02-01 06:58

  本文关键词： 浆态床 二甲醚 流程模拟 分析 热量分析　出处：《太原理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着大规模、不合理的使用化石资源，对人类生存环境造成极大的破坏，并导致大量的污染物和温室气体的排放，发展煤基合成燃料是我国能源利用方式的新主题，浆态床一步法合成二甲醚系统具有流程短、设备投资少、能耗低、一氧化碳单程转化率高等特点，已成为目前煤化工的重点发展方向。 本文应用Aspen Plus过程模拟软件对浆态床一步法合成二甲醚系统进行工艺流程模拟。在采集大量文献数据对Aspen Plus模拟环境进行校核的基础上，研究煤基合成气合成二甲醚系统、二甲醚-电联产系统、二甲醚精馏系统，并验证了模型的有效性。分析了二甲醚-电联产系统的循环比对系统能耗的影响，确定了其最佳循环比为1.5；同时分析了二甲醚精馏过程中可能的分离序列对精馏系统能耗的影响，确定了其最佳精馏分离序列的分离顺序为先分离水、再分离甲醇、最后分离二氧化碳和二甲醚。 在分析的基础上，运用热量方法和方法对浆态床一步法合成二甲醚系统进行详细的热量计算和计算，并得到该系统的能流图和流图。模拟计算结果显示：热量方法得出二甲醚的转化效率为47.16%、甲醇转化效率为6.37%、电量的转化效率为3.47%；换热后的蒸汽和冷却水的热量损耗为20.21%，无效产品（精馏段分离出的二氧化碳和余热锅炉段做完功的烟气）的热量损耗为7.42%。各流程段热损耗之和为15.66%，其中反应换热、精馏过程以及余热锅炉发电过程的热量损耗较大。方法计算得出二甲醚的转化效率为39.03%、甲醇的转化效率为5.29%、电量的转化效率为2.64%；换热后的蒸汽和冷却水的损耗为4.38%；无效产品的损耗为3.71%；各模拟单元换热的损耗之和为20.18%，，设备的损耗为3.01%，物流混合和分流过程的损耗为0.38%，发电单元的损耗为3.87%，二甲醚精馏单元的损耗为17.51%。精馏过程和反应换热过程需要供能的品质较高，造成损耗较大，如果合理分配这部分能量，不仅减少了高品质的输入，而且提高了换热后能量的利用率，从而降低损，提高效率。 综合两种分析结果可知，二甲醚精馏过程和系统换热过程中造成损失较大，亟需实现系统的热集成，使能量合理的分配，提高能量的利用效率。做完功的烟气以及精馏出的二氧化碳，能量损耗较大，但其做功能力较低，提高经济效益的效果不明显。
[Abstract]:With the large-scale, irrational use of fossil resources, the human survival environment caused great damage, and lead to a large number of pollutants and greenhouse gas emissions. The development of coal-based synthetic fuel is a new topic of energy utilization in China. The slurry bed one-step synthesis system of DME has the characteristics of short process, low investment in equipment, low energy consumption and high conversion rate of carbon monoxide. It has become the key development direction of coal chemical industry. In this paper, Aspen Plus process simulation software is used to simulate the process flow of slurry bed one-step synthetic dimethyl ether system. A large amount of literature data are collected for Aspen. Plus simulation environment based on the verification. The synthesis system of dimethyl ether from coal-based syngas, the system of dimethyl ether-electric cogeneration and the system of dimethyl ether rectification were studied. The validity of the model was verified. The effect of cycle ratio on the energy consumption of the system was analyzed. The optimum cycle ratio is 1.5. At the same time, the influence of the possible separation sequence on the energy consumption of the distillation system was analyzed, and the separation order of the optimal distillation separation sequence was determined as the separation of water first, and then methanol. Finally, carbon dioxide and dimethyl ether were separated. On the basis of the analysis, the heat calculation and calculation of the slurry bed one-step synthetic DME system are carried out by using the heat method and method. The energy flow diagram and flow diagram of the system are obtained. The simulation results show that the conversion efficiency of dimethyl ether is 47.16 and that of methanol is 6.37% by caloric method. The conversion efficiency of electricity is 3.47; The heat loss of steam and cooling water after heat transfer is 20.21%. The heat loss of ineffective products (carbon dioxide separated from distillation section and waste heat boiler flue gas) is 7.422.The sum of heat loss of each process section is 15.66, in which reaction heat transfer. The conversion efficiency of dimethyl ether and methanol is 39.03 and 5.29% respectively. The conversion efficiency of electricity is 2.64; The loss of steam and cooling water after heat transfer is 4.38. The loss of invalid product is 3.71%; The sum of heat transfer loss of each analog unit is 20.18, the loss of equipment is 3.01, the loss of material flow mixing and shunt is 0.38, and the loss of power generation unit is 3.87%. The loss of dimethyl ether distillation unit is 17.51. The quality of energy supply is high in distillation process and reaction heat transfer process, which results in a large loss. If this part of energy is reasonably distributed, the high quality input will not only be reduced. Moreover, the utilization rate of energy after heat transfer is improved, thus reducing the loss and improving the efficiency. Combined with the results of two kinds of analysis, it can be concluded that the dimethyl ether distillation process and the heat transfer process of the system cause great losses, so it is urgent to realize the thermal integration of the system so as to make the energy distribution reasonable. The energy loss of the flue gas and the carbon dioxide produced by rectification is large, but its work capacity is low, and the effect of improving economic benefit is not obvious.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ223.24

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