低浓度煤层气深冷液化装置中PSA制氮机的尾气利用探讨

摘要

为了降低低浓度煤层气深冷液化装置中变压吸附(PSA)制氮机的能耗,提高单位压缩空气的产氮率,对目前常用的PSA制氮机的工艺流程进行了改进.根据制氮工序的放空尾气具有余压的特点,增设尾气回收罐,将制氮过程中产生的尾气储存在尾气回收罐内,然后将回收罐内的尾气通入干燥塔,利用尾气代替干燥空气来反吹前端干燥塔,实现干燥塔的再生,将干燥空气全部用作制氮的原料气.制氮工艺流程改进后,尾气的余压得到了充分利用,在同样的空气进气量的情况下可以生产更多的氮气,从而达到节能的目的.%In order to reduce the energy consumption of the pressure swing adsorption (PSA) nitrogen making machine in the cryogenic liquefaction device of low-concentration coal-bed methane and increase the nitrogen yield of the unit compressed air,the technological process of the commonly used PSA nitrogen making machine was improved.To aim at the residual pressure of the exhaust gas in the process of nitrogen making,the exhaust gas recovery tank was added to collect and store the exhaust gas produced in the process of nitrogen making,the exhaust gas in this tank was then delivered into the drying tower,the front end of the drying tower was back-flushed by the exhaust gas instead of the the dry air to achieve the drying tower regeneration,and the dry air was all used as the feed gas for nitrogen making.After the improvement of the nitrogen making process,the full use of the residual pressure of the exhaust gas was made,and more nitrogen could be produced in the case of the same air intake,this thus achieved the purpose of energy saving.