气提法处理甲醇工艺冷凝液回收利用技术研究

Research on the Utilization of Methanol Process Condensate Recovery Technology by Steam Stripping Method

为解决天然气制甲醇生产过程中因工艺冷凝液直接排放造成的安全隐患、环境污染、水资源浪费、基础设施损害等问题,在充分利用现有设备设施的基础上,采用蒸汽气提方法将工艺冷凝液分阶段进行了以低压蒸汽气提回用到低压锅炉和以中压蒸汽气提回用到合成氨装置的试验,试验结果表明,甲醇装置工艺冷凝液可以经低压气提后部分作为低压锅炉补水使用,经中压气提后全部回收作为合成氨装置除盐水补水使用。2016年该技术投入应用,甲醇工艺冷凝液经合成氨装置中气提系统气提后,电导率大幅度下降,平均值为32.97μS/cm,pH值稳定,平均值为8.52,满足锅炉给水要求;同时每吨液氨产品除盐水消耗由改造前的4.2 t降到1.7 t,年节约除盐水4.73×10~4t,节约蒸汽8 000 t,技术应用取得了良好效果。

In order to solve the problems of safety hazards, environmental pollution, waste of water resources,and damage of infrastructure caused by direct discharge of process condensate in the production of methanol from natural gas, and with the full use of existing equipment and facilities, the steam stripping method is used to conduct tests of process condensate by stages, namely reusing it by lowpressure steam stripping to low- pressure boilers and by medium- pressure steam stripping to demineralization water system with the synthesis ammonia device. Test results show that the process condensate of methanol device can be used as supplementary water of low- pressure boiler after low pressure stripping, and that all recovered after medium-pressure stripping can be used as supplementary water of demineralization water system with synthesis ammonia device. In 2016, the technology has been put into operation. After the condensate of methanol process is stripped by stripping system of synthesis ammonia device, its conductivity decreases greatly, with an average value of 32.97μS/cm. Its PH value is stable, with an average value of 8.52, which met the requirements of boiler feed water. At the same time, the desalted water consumption of 1t liquid ammonia product decreases from 4.2t before the transformation to 1.7t, which saves 4.73 × 10^4 tons of desalted water and 8 000 t of steam annually, and the project achieves good results.