胺液脱除CO_(2)系统空冷器腐蚀规律研究

Corrosion Mechanism of Air Cooler in a CO Removal System with Amine Solution

采用热力学Kent-Eisenberg (KE)模型建立了贫胺液空冷器工艺仿真模型,通过Aspen plus工艺模拟软件,分析了空冷器降温(41.96~83.40℃)过程中热稳定盐、有机酸和CO_(2)等腐蚀性介质的变化规律。结果显示,空冷器前三排管束中气相摩尔分数较小,气相中热稳定盐和CO_(2)的摩尔分数分别占到55%和45%,为空冷器管束腐蚀的关键危害源。通过建立空冷管束流体动力学仿真模型,分析管束内部气相流动特性,得知空冷器第二排9~12、20、21、24、27~40号管束气相分率较大,属于腐蚀高风险区域,该结果与实际空冷器管束腐蚀位置相符合。

The air cooler process with lean amine liquid was computationally simulated by means of Kent-Eisenberg(KE) model, while the variations of heat-stable salt, organic acid, CO_(2) and other corrosive media during the cooling process in the temperature range of 83.40 ℃ to 41.96 ℃ were analyzed by means of soft wear Aspen plus. The results show that although the gas phase fraction of the first three rows of air cooler tube bundles is small, but within the gas phase, the molar fraction of heat-stable salt and CO_(2) is 55% and 45%, respectively, in fact, which may be the key hazard source for corrosion of air cooler tube bundles. Following the analysis results of the flow characteristics in air-cooled tube bundles, it follows that the high-risk corrosion regions are located at the second row tube bundles of the air cooler,namely, the tube number No.9~12, 20, 21, 24, 27~40, which are consistent with the actual corrosion locations of the tube bundle during the operation of the air cooler with lean amine liquid in the factory.