甲醇水分离塔再沸器的工程设计

Engineering design of methanol water separation tower reboiler

甲醇水分离塔再沸器作为一台较为关键的换热器,其运行效果对甲醇水分离塔乃至整个低温甲醇洗系统影响较大。首先介绍了立式热虹吸再沸器的工作原理,然后就一工程案例对甲醇水分离塔立式热虹吸再沸器的设计要点进行了探讨,并确定关键参数如下:再沸器出口的气化率宜小于20%;换热管选用标准管长3 m;入口管路系统压降占总压降的20%~30%为宜,出口管路系统压降宜占总压力降的10%~20%。计算结果表明:静压头在2 600 mm以上均能满足再沸器出口气化率要求,并确定正常液位静压头为3 000 mm;再沸器入口管路系统压降占总压降的19.2%,出口管路系统压降占总压力降的14%;高低液位下再沸器的各项工艺指标均能满足要求。该工程案例的分析计算过程为其他立式热虹吸再沸器的设计和改造提供了参考。

Methanol water separation tower reboiler is a critical heat exchanger,and its operating effect has a great impact on the methanol water separation tower and Rectisol system. The working principle of the vertical thermosyphon reboiler is introduced firstly.Then using a project case of thermosyphon reboiler of methanol water separation tower,the critical design points are discussed,and key parameters are determined as follows： reboiler outlet evaporation fraction should be less than 20%,the standard tube length of 3 meters is applied,the pressure drop of the inlet piping system accounted for 20% to 30% of the total pressure drop is appropriate,the outlet piping system pressure drop should account for 10% to 20% of the total pressure drop. Calculation results proves that：（ 1） Static pressure head above 2 600 mm can meet the requirement of reboiler outlet evaporation fraction and to determine the normal level of hydrostatic head to 3 000 mm;（ 2） The pressure drop in the reboiler inlet piping system accounted for 19. 2% of the total pressure drop,and the pressure drop in the outlet piping system accounted for 14% of the total pressure drop;（ 3） Under the high level and low level in the tower,all the technical parameters can meet the requirements. The analysis and calculation of this project case provide a reference for the design and modification of other vertical thermosyphon reboilers.