低温下甲醇改性溶剂吸收二氧化碳的研究

发布时间：2018-05-12 03:25

本文选题：甲醇 + 离子液体　；参考：《北京化工大学》2015年硕士论文

【摘要】：工业生产中,常常需要将合成气,天然气或者燃料气等物流中的C02有效地脱除。本文针对物理吸收法中甲醇吸收CO2进行了改性,分别采用离子液体[OMIM][Tf2N]和ZIF-8对其改性,研究了体系C02-甲醇一[OMIM][Tf2N]和C02-甲醇-ZIF-8的相平衡。收集了文献中甲醇吸收CO2的实验数据,拟合出CO2与甲醇和C02与离子液体基团的UNIFAC目互作用参数。测定了273.2 K、258.2 K、243.2K和228.2 K时,0-3.5MPa下,二元体系CO2(1)+甲醇(2),CO2(1)+[OMIM][Tf2N](3)以及三元体系CO2(1)+甲醇(2)+[OMIM][Tf2N](3)(w3=0.20,0.50,0.80)的气液相平衡数据。结果表明,在低温(273.2 K以下)条件下,UNIFAC对于纯甲醇、纯离子液体和甲醇与离子液体混合物中CO2的溶解度都能够很好地进行预测,并且CO2的溶解度随着温度的降低,压力的升高而增大,并且遵循以下规律：xw3:0.00xw3:0.20xw3:0.50 xw3:0.80xw3:1.00,亨利常数则呈现相反的规律。本文采用Aspen plus软件模拟了CO2的吸收分离过程,结果表明[OMIM][Tf2N]的加入不仅降低了甲醇的夹带量,同时也降低了能量的消耗。用GCMC方法计算得到了ZIF-8材料吸附CO2的吸附等温线,将本实验中的模拟计算值和文献中的实验值进行了对比,证明了模拟结果真实可靠。本文主要研究了批量合成ZIF-8的方法。在文献基础上,进行适当放大并成功地进行了ZIF-8的批量合成。测定了273.2 K,258.2 K和243.2K时,0-3.5 MPa下,二元体系C02(1)+甲醇(2)以及三元体系C02(1)+甲醇(2)+ZIF-8(3)(w3=0.05,0.10,0.15)的气液相平衡数据。分别采用UNIFAC模型和GCMC方法对C02在纯甲醇中的吸收数据和ZIF-8中吸附数据进行预测。并用二者构成的杠杆规则预测甲醇和ZIF-8混合物中的溶解度数据。实验证明,杠杆规则能够用来预测吸附吸收过程中气体溶解平衡。低压下ZIF-8的加入能增加CO2的溶解度,但高压下,增加趋势不明显。混合溶剂可以明显的降低甲醇的气相挥发量。原则上,使用ZIF-8和甲醇的混合物代替传统溶剂比较容易在工业上实现。
[Abstract]:In industrial production, CO2 must be effectively removed from logistics such as syngas, natural gas or fuel gas. In this paper, CO2 was modified by methanol in physical absorption method. The phase equilibrium of C02-methanol-[ OMIM] [Tf2N] and C02-methanol-ZIF-8 were studied by using ionic liquid [OMIM] [Tf2N] and ZIF-8 respectively. The experimental data of methanol absorption of CO2 in literature were collected and the UNIFAC mesh interaction parameters of CO2 with methanol and CO2 with ionic liquid group were fitted. The vapor-liquid phase equilibrium data of the binary system CO _ 2O _ (1) (OMIM) [Tf2N] ~ (3) and ternary system CO _ (2) O _ (1) [OMIM] [Tf2N] (0.200.500.80) have been measured at 273.2 K ~ (2 +) 258.2 K ~ (2 +) K ~ (2 +) and 228.2 K ~ (0.5) MPA. The results show that the solubility of CO2 in pure methanol, pure ionic liquid and mixture of methanol and ionic liquid can be well predicted under low temperature (< 273.2 K), and the solubility of CO2 decreases with temperature. The pressure increases and follows the following rule: xw3: 0.00xw3: 0.20xw3: 0.50xw3: 0.80xw3: 1.00. the Henry constant shows the opposite rule. In this paper, the absorption and separation process of CO2 is simulated by Aspen plus software. The results show that the addition of [OMIM] [Tf2N] not only reduces the entrainment of methanol, but also reduces the energy consumption. The adsorption isotherms of CO2 adsorbed by ZIF-8 materials were calculated by GCMC method. The simulated results were compared with the experimental values in literature, and the simulation results were proved to be true and reliable. In this paper, the method of batch synthesis of ZIF-8 is studied. On the basis of the literature, the batch synthesis of ZIF-8 was carried out successfully. The vapor-liquid phase equilibrium data of binary system C02O1) methanol-2) and ternary system C02O1) methanol-2) at 273.2 Ku 258.2K and 243.2K were determined. The absorption data of CO2 in methanol and adsorption data in ZIF-8 were predicted by UNIFAC model and GCMC method respectively. The solubility data of methanol and ZIF-8 mixtures were predicted by the lever rule. The experimental results show that the lever rule can be used to predict the equilibrium of gas dissolution in the process of adsorption and absorption. The solubility of CO2 can be increased by adding ZIF-8 at low pressure, but the increasing trend is not obvious at high pressure. The mixed solvent can obviously reduce the volatile amount of methanol in the gas phase. In principle, it is easier to use a mixture of ZIF-8 and methanol instead of traditional solvents.
【学位授予单位】：北京化工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ413.2;TQ028.14

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