油田含CO2伴生气变压吸附材料实验研究

Experimental study on pressure swing adsorption material for CO2 separation from EOR produced gas

关键词:  变压吸附  竞争吸附  油水污染  分离系数  吸附等温线

Key words:  pressure swing adsorption  competitive adsorption  moisture and oil pollution  selectivity  adsorption equilibrium isotherms

摘要:

变压吸附工艺是国内小规模CO₂驱产出气处置的常用手段,而吸附剂是吸附分离的基础。选用6种沸石类吸附剂,测试了CO₂/CH₄单组分吸附平衡等温线,分析了温度对吸附量的影响。优选了两种材料进行了CO₂-CH₄混合气体竞争吸附实验,重点分析了温度、压力、气体组分、CO₂含量等因素对吸附剂吸附分离效果的影响,评价了油、水含量对吸附剂的损伤。实验结果表明:吸附剂的分离系数与混合气体中CO₂含量无明显相关性,但吸附体系压力的变化对混合气体分离效果影响较大。在初始气体CO₂摩尔分数50%、温度20 ℃、压力2.5 MPa条件下,优选的吸附剂13X对混合气体的分离系数为25。油水的存在会对吸附剂的分离性能产生较大影响,在温度20 ℃、压力2.5 MPa、13X吸附剂含水摩尔分数10%及含油摩尔分数10%条件下,吸附总量分别下降32%和78%,分离系数分别下降48%和78%。

Abstract:

Pressure swing adsorption(PSA) process is a common method to disposal CO₂-flooding produced gas, and the adsorbent is the basis of adsorption separation. In this paper, six kinds of adsorbents are selected to measure the adsorption equilibrium isotherms of CO₂ and CH₄, and the influences of temperature are analyzed. Two zeolites with excellent separation performance have been used for subsequent experiments about CO₂-CH₄ binary adsorption equilibrium. The influences of various factors, such as temperature, pressure, gas composition, and CO₂ content on the CO₂ separation performance are analyzed. Moreover, the damage rate of the moisture and oil content to the adsorbent are also evaluated. The experimental results show that the selectivity of 13X has no obvious correlation with CO₂ content in the mixture gas, but the system pressure has a great effect on the separation performance. Under the condition with a CO₂ content of 50%, a temperature of 20 ℃ and a pressure of 2.5 MPa, the selectivity of 13X for the mixed gas is 25. The moisture and oil content can tremendously weaken separation performance of zeolites. At 20 ℃ and 2.5 MPa, 10% of water content and 10% of oil content can decrease the adsorption amount of 13X by 32% and 78% respectively, and the selectivity of 13X will decrease 48% and 78% respectively.