This research proposes a modified two-dimensional Peng-Robinson equation model to predict adsorption isotherm in adsorbate-adsorbent systems. The parameters of the proposed model are calculated by using the optimizati...This research proposes a modified two-dimensional Peng-Robinson equation model to predict adsorption isotherm in adsorbate-adsorbent systems. The parameters of the proposed model are calculated by using the optimization of experimental data for the different single gas adsorption systems at various temperatures. The experimental adsorption equilibrium data of adsorbate-adsorbent systems was compared with the calculated results in our proposed model and the two-dimensional Hill-deBoer equation model. The proposed model as indicated in the results shows a better prediction of the experimental results compared with two others.展开更多
Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The ind...Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.展开更多
In the design of chemical processes,such as catalytic cracking of bitumen and heavy oil,the knowledge of phase behavior at the critical endpoint is essential.Based on the PR equation of state,the algorithm developed b...In the design of chemical processes,such as catalytic cracking of bitumen and heavy oil,the knowledge of phase behavior at the critical endpoint is essential.Based on the PR equation of state,the algorithm developed by Heidemann and Khalil for calculating critical properties was used to compute critical points.An algorithm for determining the equilibrium phase of the critical point using the tangent plane criterion was developed,and was used to calculate the critical endpoints of different mixtures,including non-polar,polar and associating systems.The critical endpoint,representing the type of the phase behavior,was employed to fit the interaction parameter of mixtures in critical state at high pressure.Lines of critical endpoints for ternary mixtures were also determined with the algorithm.展开更多
Based on the surface chemical potential and Peng-Robinson equation of state,a newmodel is proposed to predict and correlate the surface tensions of binary and ternary liquid mix-tures.Using this method,the surface ten...Based on the surface chemical potential and Peng-Robinson equation of state,a newmodel is proposed to predict and correlate the surface tensions of binary and ternary liquid mix-tures.Using this method,the surface tensions of 73 binary and 8 ternary systems are calculatedwith average relative deviations 1.35% and 3.52% respectively.The proposed model is simple, re-liable and accurate.展开更多
For further improving the representation of mixture VLE data,the local composition version of CCORequation of state has been developed and tested on 42 sets low-pressure and high-pressure as well as polarand nonpolar ...For further improving the representation of mixture VLE data,the local composition version of CCORequation of state has been developed and tested on 42 sets low-pressure and high-pressure as well as polarand nonpolar VLE data.The data reduction results were compared with conventional quadratic mixing ruleand activity coefficient method.The comparison with quadratic mixing rule showed that the local composition version significantly im-proved the data fitting of polar systems,especially for those highly nonideal mixtures where quadratic mixingrule failed to fit satisfactorily.The comparison with the well-known activity coefficient method——Hayden-O’Connell-Wilson model,indicated that this new version gave,in general,better fit to those low-pressure strongly polar systems,which traditionally has to be treated by activity coefficient approach.展开更多
基于PR状态方程,结合四种不同混合规则,利用Heidemann和Khalil的临界性质计算方法,关联了二十一种不同二元体系的临界温度并预测了其临界压力,其中包括非极性、极性和缔合三类体系。对临界温度的关联结果表明,四种混合规则对所有体系均...基于PR状态方程,结合四种不同混合规则,利用Heidemann和Khalil的临界性质计算方法,关联了二十一种不同二元体系的临界温度并预测了其临界压力,其中包括非极性、极性和缔合三类体系。对临界温度的关联结果表明,四种混合规则对所有体系均适用。对临界压力的预测结果表明,四种混合规则中van der Waals-1及Panagiotopoulos-Reid混合规则对非极性-极性(四偶极)体系的估算精度高,而van der Waals-2和Sadus van derWaals-2混合规则更适用于非极性-非极性体系及极性-极性(四偶极)体系。对于缔合体系,随着组分缔合能力的增强,四种混合规则的预测误差均增大,除含1-丁醇及苯组分的体系外有待于寻找更合适的状态方程及混合规则。展开更多
文摘This research proposes a modified two-dimensional Peng-Robinson equation model to predict adsorption isotherm in adsorbate-adsorbent systems. The parameters of the proposed model are calculated by using the optimization of experimental data for the different single gas adsorption systems at various temperatures. The experimental adsorption equilibrium data of adsorbate-adsorbent systems was compared with the calculated results in our proposed model and the two-dimensional Hill-deBoer equation model. The proposed model as indicated in the results shows a better prediction of the experimental results compared with two others.
文摘Cubic equations of state(EOSs) are simple and easy at calculation. One way of improving the accuracy of a cubic EOS is through the modification of temperature-dependent energy parameter by using alpha-function.The industrial applications of natural gas are very wide and as a result, prediction of thermodynamic properties and phase behavior of natural gas is an important part of design for such processes. In this work we develop a newα-function for the Peng-Robinson(PR) EOS with the parameters optimized especially for natural gas components.The parameters are generalized as a linear function of acentric factor. The results are compared to the predictions from original PR EOS and other α-functions in literature. It is shown that the new α-function presents a good accuracy with the average deviation of 1.42% for natural gas components.
文摘In the design of chemical processes,such as catalytic cracking of bitumen and heavy oil,the knowledge of phase behavior at the critical endpoint is essential.Based on the PR equation of state,the algorithm developed by Heidemann and Khalil for calculating critical properties was used to compute critical points.An algorithm for determining the equilibrium phase of the critical point using the tangent plane criterion was developed,and was used to calculate the critical endpoints of different mixtures,including non-polar,polar and associating systems.The critical endpoint,representing the type of the phase behavior,was employed to fit the interaction parameter of mixtures in critical state at high pressure.Lines of critical endpoints for ternary mixtures were also determined with the algorithm.
基金Project 29676020 supported by the National Nature Science Foundation of China.
文摘Based on the surface chemical potential and Peng-Robinson equation of state,a newmodel is proposed to predict and correlate the surface tensions of binary and ternary liquid mix-tures.Using this method,the surface tensions of 73 binary and 8 ternary systems are calculatedwith average relative deviations 1.35% and 3.52% respectively.The proposed model is simple, re-liable and accurate.
文摘For further improving the representation of mixture VLE data,the local composition version of CCORequation of state has been developed and tested on 42 sets low-pressure and high-pressure as well as polarand nonpolar VLE data.The data reduction results were compared with conventional quadratic mixing ruleand activity coefficient method.The comparison with quadratic mixing rule showed that the local composition version significantly im-proved the data fitting of polar systems,especially for those highly nonideal mixtures where quadratic mixingrule failed to fit satisfactorily.The comparison with the well-known activity coefficient method——Hayden-O’Connell-Wilson model,indicated that this new version gave,in general,better fit to those low-pressure strongly polar systems,which traditionally has to be treated by activity coefficient approach.
文摘基于PR状态方程,结合四种不同混合规则,利用Heidemann和Khalil的临界性质计算方法,关联了二十一种不同二元体系的临界温度并预测了其临界压力,其中包括非极性、极性和缔合三类体系。对临界温度的关联结果表明,四种混合规则对所有体系均适用。对临界压力的预测结果表明,四种混合规则中van der Waals-1及Panagiotopoulos-Reid混合规则对非极性-极性(四偶极)体系的估算精度高,而van der Waals-2和Sadus van derWaals-2混合规则更适用于非极性-非极性体系及极性-极性(四偶极)体系。对于缔合体系,随着组分缔合能力的增强,四种混合规则的预测误差均增大,除含1-丁醇及苯组分的体系外有待于寻找更合适的状态方程及混合规则。
