低温甲醇洗CO_2闪蒸系统优化设计

Optimal Design for CO_2 Flash in Rectisol Unit

介绍了低温甲醇洗工艺流程,随着对高纯度CO_2产品气的需求越来越大,以及环保要求越来越严格,为最大能力回收CO_2气体,CO_2闪蒸系统一般设置气提/CO_2解吸塔、两段式循环甲醇闪蒸塔和甲醇循环泵。针对装置能耗问题,通过优化循环甲醇闪蒸塔设备结构,取消了甲醇循环泵及相关阀门和控制系统。结果显示,该优化设计不但简化工艺流程,而且减少了装置投资及操作费用,以18万t/a合成氨配套低温甲醇洗装置计算,该工艺改造节约了固定资产投资约76.47万元,每年降低能耗约39.2万元,达到了节能和节约投资的双重效果。

This paper introduces the process flow of rectisol unit. Since the demand for high purity CO2 keeps growing and related environmental requirements become stricter and stricter,CO2 flash system is equipped with gas stripping/CO2 desorption tower, two-phase circulation methanol flash tower and methanol circulation pump for the best recycling of CO2. In the aspect of energy consumption, the structure of methanol flash tower is optimized by cancelling methanol circulation pump as well as related valves and controlling system. The final result indicates that this optimal design doesn＇t only simplify the process flow, but also reduces equipment investment and operation cost. Provided each reetisol unit is paired with 180 000 t/a synthesis ammonia, this optimal design can save about 764 700 RMB for fixed investment, and reduce energy consumption by 392 000 RMB,thus saving cost and energy at the same time.