基于双产品回收的C02驱采伴生气低温分馏工艺

针对某油田CO2驱采伴生气气质特性以及双产品回收指标的要求,运用HYSYS软件数值研究基于CO2-天然气双产品回收的三塔、四塔低温分馏工艺,分析乙烷回收塔塔底温度和原料气中CO2含量对两工艺CO2产品量、添加剂用量、工艺能耗的影响规律,并进行三塔/四塔工艺以及四塔工艺改进前后的对比分析.结果表明:三塔/四塔工艺的C02产量、添加剂用量以及比热耗均随乙烷回收塔塔底温度的升高而增大,比冷耗呈先减后增变化;随着原料气CO2浓度的增大,三塔/四塔工艺的CO2产品量增加,而添加剂用量/比冷耗/比热耗降低;四塔工艺改进后CO2产品量稍有降低,添加剂用量稍有增加,但比冷耗/比热耗平均降低14.4％/30.9％.结论认为,四塔工艺在总能耗、冷/热能耗及添加剂用量上都远低于三塔工艺,且CO2回收率高,改进后的四塔工艺则简化了工艺流程且节能效果更为显著.

Cryogenic distillation processes aimed to recover dual products from CO2 EOR associated gas

Based on characteristics of CO2 EOR associated gas and index requirements of CO2-natural gas dual products recovery,the software HYSYS was applied to study the three & four columns cryogenic distillation processes.Laws that CO2 output,additive dosage and process energy consumption of this two processes changing with the bottom temperature of ethane recovery column and CO2 mole content in the feed gas were analyzed,and comparative studies on the three & four columns process and before & after the four columns process were carried out.Within the scope of the numerical experiment parameters,CO2 output,additive dosage and specific heat consumption all increased but specific cold consumption first decreased and then increased with the increase of bottom temperature of ethane recovery column for the three/four columns process.For the two processes,with the increase of CO2 concentration in the feed gas,CO2 output was increased,but additive dosages,specific cold/heat consumptions were decreased.Additional,with the four columns process improved,CO2 output has a slight decrease and additive dosage has a slight increase,but specific cold/heat consumptions reduced by an average of about 14.4％ and 30.9％ respectively.Total/cold/heat energy consumptions and additive dosage of the four columns process were far lower and the CO2 recovery rate was higher than that of the three columns process.The improved four columns process was more simple and more energy efficient.