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Yi-Wei Wang Frederick D. Otto Alan E. Mather Shuo Xu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1991,51(2):197-208
The solubilities of N2O and CO2 in aqueous sulfolane solutions and pure sulfolane solvent, and the diffusivities of N2O in aqueous sulfolane solutions were measured and correlated over the temperature range from 20° to 85°C; also, the data for density and viscosity that were needed in this experimental work were measured. This experiment revealed that the parameter of N2O analogy method depends not only on the temperature, but also on the character of the solvent. Therefore, different solvents possess different analogy parameters. Only for dilute aqueous solutions can the parameter be replaced by the analogy parameter of water. The results also proved that the sum of volume fractions contribution is a simple method to estimate the solubility in aqueous sulfolane solutions over the whole range of the concentrations and experimental temperatures, with an average deviation of less than 4·0%. 相似文献
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A comparative kinetics study of CO2 absorption into aqueous DEEA/MEA and DMEA/MEA blended solutions 下载免费PDF全文
Wusan Jiang Xiao Luo Hongxia Gao Zhiwu Liang Bin Liu Paitoon Tontiwachwuthikul Xiayi Hu 《American Institute of Chemical Engineers》2018,64(4):1350-1358
The kinetics of CO2 absorption into aqueous solutions of N,N‐diethylethanolamine (DEEA), and N,N‐dimethylethanolamine (DMEA), and their blends with monoethanolamine (MEA) have been studied in a stopped‐flow apparatus. The kinetics experiments were carried out at the concentrations of DEEA and DMEA varying from 0.075 to 0.175 kmol/m3, respectively, and that of MEA ranging between 0.0075 and 0.0175 kmol/m3, over the temperature range of 293–313 K. Two kinetics models are proposed to interpret the reaction in the blended amine systems and the results show that the model which incorporates the base‐catalyzed hydration mechanism and termolecular mechanism resulted in a better prediction. Furthermore, the kinetics behaviors of CO2 absorption into two blended systems are comprehensively discussed according to their molecular structures. It can be concluded that the interaction between tertiary amines and primary amines as well as the alkyl chain length of tertiary amines have a significant influence on the kinetics. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1350–1358, 2018 相似文献
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利用物理溶剂环丁砜替代部分水,采用气液搅拌实验装置和真实热流量热法测定了环丁砜对乙醇胺(MEA)溶液吸收和解吸二氧化碳(CO2)过程的影响,考察了CO2循环负载、吸收速率、吸收热和解吸热等性质变化。研究表明:环丁砜对MEA溶液负载CO2的吸收热影响较小,但对吸收速率、循环吸收容量和解吸过程影响较大。环丁砜可降低MEA溶液对CO2的表观吸收速率,且随CO2负载量的增大,降幅也逐渐变大。环丁砜有利于富液解吸过程,加快解吸速率,增大CO2解吸程度,同时单位热流负荷、单位冷流负荷和单位能耗均有不同程度的降低。在燃煤电厂烟气条件下,20% MEA+20% sulfolane体系相对20% MEA体系,其表观吸收速率平均降低约10%,CO2循环吸收容量增加24%,单位CO2解吸能耗降低18%。 相似文献
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The solubility of H, S and CO2 in sulfolane (tetrahydrothiophene-1, 1—dioxide) has been measured at 40°C and 100°C at pressures up to 2350 kPa and 5900 kPa respectively. The Henry's constants obtained from the data are in agreement with those of Rivas and Prausnitz. 相似文献
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Carbon dioxide was absorbed into aqueous polyacrylamide (PAA) solution containing methyl-diethanolamine (MDEA) in a flat-stirred
vessel to investigate the effect of non-Newtonian rheological behavior of PAA on the rate of chemical absorption of CO2, where the reaction between CO2 and MDEA was assumed to be a first-order reaction with respect to the molar concentration of CO2 and MDEA, respectively. The liquid-side mass transfer coefficient (kL), which was obtained from the dimensionless empirical equation containing the viscoelasticity properties of a non-Newtonian
liquid, was used to estimate the enhancement factor due to chemical reaction. PAA with elastic property of non-Newtonian liquid
made the rate of chemical absorption of CO2 accelerate compared with a Newtonian liquid 相似文献
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Absorption rates for CO2 into aqueous solutions of TEA, MDEA and blends of MEA with MDEA and TEA were measured in a stirred cell by a method similar to that used by Laddha and Danckwerts (1981). Second order rate constants for CO2-TEA and CO2-MDEA were obtained from the single amine data for temperatures in the range of 25-60°C. A modified pseudo first order model based on the film theory is used to predict the rate of absorption of CO2 into mixed amine solutions. This model accounts for the variation of amine concentration in the film and assumes a shuttle mechanism for rate enhancement. Bulk liquid concentrations of the various species present are obtained from a simplified thermodynamic model. The model predicts absorption rates that are in agreement with experimental measurements. 相似文献
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The solubility of hydrogen sulphide, carbon dioxide, and their mixtures has been measured at 40° and 100°C in a mixed solvent consisting of 20.9 wt% MDEA (methyldiethanolamine), 30.5 wt% sulfolane (tetrahydrothiophene-1, 1-dioxide), and 48.6 wt% water. The results have been compared with those for aqueous 2.0 mol/dm3 MDEA and an analogous mixed solvent, containing AMP (2-amino-2-methyl-1-propanol), which are available in the literature. These data were used to modify the solubility model of Deshmukh and Mather (1981) to account for the mixed solvent effects on the system thermodynamics. Results show that the model is useful as a first approximation in predicting acid gas solubilities; agreement with experiment was generally found to be within £15%. 相似文献
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Jicai Huang Maoqiong Gong Zhaohu Sun Xueqiang Dong Jun Shen Jianfeng Wu 《American Institute of Chemical Engineers》2017,63(6):2386-2393
A multiphase and multicomponent mass transfer model of CO2 absorbed in aqueous N‐methyldiethanolamine and piperazine (PZ) was built in the study. In the model, a simple method of mass transfer between phases was proposed. Besides, the hydrodynamics, thermodynamics, and complex reversible chemical reaction were considered simultaneously. The model was validated by comparing with the previous experimental data which showed that simulated results can represent the experimental data with reasonable accuracy. Based on the model, the effects of gas velocity, liquid load and CO2 loading on the absorption rate, and enhancement factor were analyzed. Model results showed that the enhancement factor increased with a rising gas velocity while decreased with a rising liquid load or CO2 loading. The change of enhancement factor with CO2 loading was similar to that of equilibrium concentration of PZ which indicated that PZ was significant to the absorption process. Furthermore, the distributions of specie concentrations were discussed in detail. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2386–2393, 2017 相似文献
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The development of kinetics model for CO2 absorption into tertiary amines containing carbonic anhydrase 下载免费PDF全文
Bin Liu Xiao Luo Zhiwu Liang Wilfred Olson Helei Liu Raphael Idem Paitoon Tontiwachwuthikul 《American Institute of Chemical Engineers》2017,63(11):4933-4943
CO2 absorption into aqueous solutions of two tertiary alkanolamines, namely, MDEA and DMEA with and without carbonic anhydrase (CA) was investigated with the use of the stopped‐flow technique at temperatures in the range of 293–313 K, CA concentration varying from 0 to 100 g/m3 in aqueous MDEA solution with the amine concentration ranging from 0.1 to 0.5 kmol/m3, and CA concentration varying from 0 to 40 g/m3 in aqueous DMEA solution with the amine concentration ranging from 0.05 to 0.25 kmol/m3. The results show that the pseudofirst‐order reaction rate (k0, amine; s?1) is significantly enhanced in the presence of CA as compared with that without CA. The enhanced values of the kinetic constant in the presence of CA has been calculated and a new kinetics model for reaction of CO2 absorption into aqueous tertiary alkanolamine solutions catalyzed by CA has been established and used to make comparisons of experimental and calculated pseudo first‐order reaction rate constant (k0, with CA) in CO2‐MDEA‐H2O and CO2‐DMEA‐H2O solutions. The AADs were 15.21 and 15.17%, respectively. The effect of pKa on the CA activities has also been studied by comparison of CA activities in different tertiary amine solutions, namely, TEA, MDEA, DMEA, and DEEA. The pKa trend for amines were: DEEA > DMEA > MDEA > TEA. In contrast, the catalyst enhancement in amines was in the order: TEA> MDEA> DMEA> DEEA. Therefore, it can be seen that the catalyst enhancement in the amines decreased with their increasing pKa values. © 2017 American Institute of Chemical Engineers AIChE J, 2017 相似文献
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N-甲基二乙醇胺溶液对H2S和CO2的吸收模拟 总被引:1,自引:0,他引:1
采用N-甲基二乙醇胺(MDEA)吸收炼化过程中干气及液态烃中过量的H2S和CO2,以达到生产要求。文中利用PRO/II软件对MDEA溶液吸收H2S和CO2的过程,采用合适的热力学模型(Electrolyte-NRTL),建立吸收塔模型进行模拟。研究了进料气液质量比、进料温度、操作压力、塔板高度、吸收液浓度等条件的改变对吸收效果的影响,并对操作条件进行评估。MDEA溶液对CO2的吸收效果不是很理想,由于伯、仲胺可直接与CO2反应,故向溶液中添加DEA,采用PRO/II的Kent-Eisenberg模型对MDEA/DEA混合胺的吸收状况进行模拟,其吸收效果较理想。文中对现有装置提出了一些技术改造建议。 相似文献
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Absorption rate of CO2 into aqueous solution of N-methyldiethanolamine (MDEA) blended with diethanolamine (DEA) and piperazine (PZ) was studied and a kinetic model was established. It is shown that homogeneous activation mechanism could explain this absorption process. The absorption rate coefficients of carbon dioxide into MDEA aqueous solution blended with DEA, PZ or DEA PZ were compared with each other. The results demonstrated that the different activation effect of DEA, PZ and DEA PZ on the carbon dioxide absorption comes from the difference in CO2 combination rate, transport of PZ and DEA to MDEA and the regeneration rate of PZ and DEA. 相似文献
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Observed pseudo‐first‐order rate constants (ko) for the reaction between CO2 and 2‐((2‐aminoethyl) amino) ethanol (AEEA) were measured using the stopped‐flow technique in an aqueous system at 298, 303, 308 and 313 K, and in non‐aqueous systems of methanol and ethanol at 293, 298, 303 and 308 K. Alkanolamine concentrations ranged from 9.93 to 80.29 mol m?3 for the aqueous system, 29.99–88.3 mol m?3 for methanol and 44.17–99.28 mol m?3 for ethanol. Experimentally obtained rate constants were correlated with two mechanisms. For both the aqueous‐ and non‐aqueous‐AEEA systems, the zwitterion mechanism with a fast deprotonation step correlated the data well as assessed by the reported statistical analysis. As expected, the reaction rate of CO2 in the aqueous‐AEEA system was found to be much faster than in methanol or ethanol. Compared to other promising amines and diamines studied using the stopped‐flow apparatus, the pseudo‐first‐order reaction rate constants were found to obey the following order: PZ (cyclic‐diamine) > EDA (diamine) > AEEA (diamine) > 3‐AP (primary amine) > MEA (primary amine) > EEA (primary amine) > MO (cyclic‐amine). The reaction rate constant of CO2 in aqueous‐AEEA was double that in aqueous‐MEA, and the difference increased with an increase in concentration. All reaction orders were practically unity. With a higher capacity for carbon dioxide and a higher reaction rate, AEEA could have been a good substitute to MEA if not for its high thermal degradation. AEEA kinetic behaviour is still of interest as a degradation product of MEA. © 2012 Canadian Society for Chemical Engineering 相似文献
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Kinetics of CO2 absorption into a novel 1‐diethylamino‐2‐propanol solvent using stopped‐flow technique 下载免费PDF全文
Helei Liu Zhiwu Liang Teerawat Sema Wichitpan Rongwong Chen Li Yanqing Na Raphael Idem Paitoon Tontiwachwuthikul Raphael Idem Paitoon Tontiwachwuthikul 《American Institute of Chemical Engineers》2014,60(10):3502-3510
A stopped‐flow apparatus was used to measure the kinetics of carbon dioxide (CO2) absorption into aqueous solution of 1‐diethylamino‐2‐propanol (1DEA2P) in terms of observed pseudo‐first‐order rate constant (ko) and second‐order reaction rate constant (k2), in this work. The experiments were conducted over a 1DEA2P concentration range of 120–751 mol/m3, and a temperature range of 298–313 K. As 1DEA2P is a tertiary amine, the base‐catalyzed hydration mechanism was, then, applied to correlate the experimental CO2 absorption rate constants obtained from stopped‐flow apparatus. In addition, the pKa of 1DEA2P was experimentally measured over a temperature range of 278–333 K. The Brønsted relationship between reaction rate constant (obtained from stopped‐flow apparatus) and pKa was, then, studied. The results showed that the correlation based on the Brønsted relationship performed very well for predicting the absorption rate constant with an absolute average deviation of 5.2%, which is in an acceptable range of less than 10%. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3502–3510, 2014 相似文献
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Acceleration of the reaction of carbon dioxide into aqueous 2-amino-2-hydroxymethyl-1,3-propanediol solutions by piperazine addition 总被引:1,自引:0,他引:1
Francis Bougie 《Chemical engineering science》2009,64(9):2011-136
In this work, the kinetics of the reaction between CO2 and piperazine-activated aqueous solutions of a sterically hindered alkanolamine, 2-amino-2-hydroxymethyl-1,3-propanediol (AHPD) was studied in a wetted wall column contactor at 303.15, 313.15 and 323.15 K. The AHPD concentration in the aqueous solutions was kept at while the piperazine (PZ) concentration varied in the range . Under pseudo-first-order CO2 absorption conditions, the overall pseudo-first-order rate constants were determined and reaction rate parameters were calculated with a non-linear regression from the overall reaction rate constant. The ratio of the diffusivity and Henry's law constant for CO2 in solutions was estimated by applying the N2O analogy and the Higbie penetration theory, using the physical absorption data of CO2 and N2O in water and of N2O in amine solutions. Piperazine was found to be an effective activator in the aqueous AHPD solutions, as the addition of small amounts of PZ to these solutions has a significant effect on the enhancement of the CO2 absorption rate for all studied temperatures. 相似文献
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为满足有机胺法脱硫设计开发的需要,采用动态吸收法测定了填料塔中哌嗪二胺(PA-A)水溶液吸收低浓度SO2的体积总传质系数KGa,考察了吸收工艺参数如吸收液中的PA-A浓度和初始pH值、液相流率、吸收温度、进气SO2浓度及流速等对KGa的影响。结果表明:KGa随着吸收液中的PA-A浓度和初始pH值、液相喷淋密度的增加而增大;随着吸收温度、气相流率及进气SO2浓度的增加而减小。通过实验结果分析得到体积总传质系数KGa与气液相流率比(qG/qL)之间符合指数关系式,该经验关系可用于工程设计计算。 相似文献
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The design of sour‐gas treating processes with alkanolamine solvents requires knowledge of the vapour–liquid equilibrium (VLE) of the aqueous acid gas–alkanolamine systems. Representation of the experimental data with a thermodynamically rigorous model is required, so that one can systematically correlate and predict the VLEs of these systems. The modified Clegg–Pitzer equations have been used to correlate and predict the VLE of CO2 in the aqueous N‐methyldiethanolamine (MDEA) and 2‐amino‐2‐methyl‐1‐propanol (AMP) systems. Differential evolution (DE), an evolutionary computational technique, has been used for parameter estimation of the developed VLE model in an effort to predict the VLE of CO2 in aqueous MDEA and AMP solutions with a comparable accuracy to that by using the non‐traditional simulated annealing (SA) and deterministic technique like Levenberg–Marquardt (LM), if not better. In this work, the DE/rand‐best/1/bin strategy has been used for finding near global minimum solutions to the multivariable optimization problem as a part of the numerical solution of the developed model. 相似文献