二氧化碳气提法尿素装置中压吸收塔模拟分析

Simulation Analysis of Medium Pressure Absorption Tower in Urea Production Unit by CO_2 Stripping

运用ChemCAD流程模拟软件对改进型二氧化碳气提法尿素装置的中压吸收塔进行了模拟分析,对吸收塔上段分别采用稀氨水和纯水为吸收剂时的两种工艺进行了模拟计算。模拟计算结果表明:吸收塔上段采用纯水吸收可使尾气氨排放得到有效控制,当纯水用量为80 kmol/h时,尾气中的氨摩尔分数从0.40%下降至0.02%,氨回收率可提高9.11%,年减少氨排放157.9 t。

Simulation analysis is done with the ChemCAD flowsheet simulation software of the medium-pressure absorption tower in the improved version of a urea production unit by CO2 stripping, and analog computation is carried out on the upper section of the absorption tower with two processes using respectively dilute aqua ammonia and pure water as absorbents. The results show that the absorp- tion with pure water in the upper section can effectively control the ammonia in the tail gas discharged. When the quantity of pure water used is 80 kmoL/h, the mole fraction of ammonia in the tail gas drops from 0.40% to 0.02% , ammonia recovery can rise by 9.11% and the amount of ammonia discharged can be decreased by 157.9 t.