【作者】 陈旭东；

【导师】 袁希钢；

【作者基本信息】 天津大学 ， 化学工程， 2009， 硕士

【摘要】 本文提出了一种新型精馏节能技术一塔段透热能量集成精馏技术。它是利用精馏塔精馏段作为热源,提馏段作为热阱,相互之间进行透热,在完成各自分离任务的同时,减少塔顶、塔底能耗。本文以苯-甲苯、乙醇-水体系为例,对塔段透热全回流实验装置进行了模拟；同时对苯-甲苯体系的普通双塔塔段透热精馏和乙醇-苯共沸物系的塔段透热变压精馏工艺进行了模拟研究,并与双效精馏工艺进行了用能对比。本文用表示透热能力大小的塔板透热系数UA建立模型的透热关系,分析了不同UA和塔段压力差下塔段透热精馏的流体特性和节能效果。结果表明塔段透热改变了塔内负荷分布,应该采用更为合适的变直径精馏塔；塔段透热系数UA和两塔段压力差显著影响透热过程,对于全回流实验装置,如果UA基本不发生变化,两塔段压力差是透热量决定因素。将模型的UA与文献中总传热系数U进行了比较换算,结果与之相符。能量分析表明,透热能量集成会减小精馏塔段冷凝负荷和提馏塔段塔釜负荷。与双效精馏节能相比,由于透热能量集成减少了精馏操作不可逆性,所需公用工程品位有所降低,但总用能有所增加。在合适的UA之下,操作费用与双效精馏相比可减少13%左右。乙醇-苯共沸物系变压透热精馏的分离模拟计算表明,与高浓度比乙醇进料相比,低浓度比乙醇进料工艺更适合选用塔段透热精馏工艺方式。更多还原

【Abstract】 As a new and energy-saving distillation technology, a diabatic distillation with heat integration between column sections is studied by means of simulation. This technique uses rectifying section of a column as a heat source and stripping section of another column as a heat sink, for the heat integration between columns. Two binary mixtures, benzene-toluene, ethanol-water, are taken as base case for the simulation of a total reflux diabatic heat integration experimental setup. Simulation of diabatic distillation with heat integration for two conventional columns and azeotropic pressure-swing distillation are also conducted using benzene-toluene and ethanol-benzene systems. Energy costs are compared with those of double effect distillation.The stage diabatic coefficient, UA, which represents the capacity of heat transfer, is proposed to characterize the diabatic heat transfer. Fluid dynamics and energy-saving performance at different UA and different column pressure difference are analyzed. Simulation results shows that diabatic distillation process changes the column loading distribution in the column and a column with changing diameter should be used for diabatic heat integrated distillation. UA and pressure difference between the two column sections influence effectively diabatic distillation with heat integration. For a constant UA, pressure difference is the most important factor determining the amount of diabatic heat transfer. UA proposed for the experimental setup is found to be consistent with heat transfer coefficient U in previous literature after conversion.Heat balance analysis shows that diabatic heat integration reduces the condensing and reboiling load in the overhead of the heat source column and on the bottom of the sink column. Compared with the double effect distillation, diabatic heat integration reduces the irreversibility of distillation and utility grade has lowered, but total energy input is a little higher. Economical analysis shows thatwith appropriate UA, operating cost can be saved up to 13% compared with double effect distillation. In azeotropic pressure-swing distillation lower ethanol-benzene concentration ratio feed is more suitable for using the proposed diabatic heat integration technology than higher concentration ratio one.更多还原