The process of removing dilute CO 2 from air by using the mixtures of K 2CO 3 and piperazine (PZ) was conducted in a random packed tower at 25 ℃.The results showed that PZ increased the absorption rate of CO 2 into a...The process of removing dilute CO 2 from air by using the mixtures of K 2CO 3 and piperazine (PZ) was conducted in a random packed tower at 25 ℃.The results showed that PZ increased the absorption rate of CO 2 into aqueous K 2CO 3 much more effectively than MEA or DEA. The volumetric overall mass transfer coefficient (K Ga) of dilute CO 2 absorption into K 2CO 3/PZ was measured.The K Ga value was evaluated over the ranges of main operating variables: the concentration of CO 2 in inlet gas, gas flow rate, liquid loading, CO 2 loading in liquid phase,and the concentrations of K 2CO 3 and PZ. The test showed that K Ga could be remarkably improved by increasing liquid loading and the concentration of PZ, and decreasing the concentration of CO 2 in inlet gas, as well as the gas flow rate and CO 2 loading in liquid phase.展开更多
Three types of composite PDMS membranes were prepared by using PAN, CA, and PVDF as support materials and used to separate ethanol from aqueous solution by pervaporation.The experimental results evidently demonstrated...Three types of composite PDMS membranes were prepared by using PAN, CA, and PVDF as support materials and used to separate ethanol from aqueous solution by pervaporation.The experimental results evidently demonstrated that the support layer had a significant impact on the flux and selectivity of composite PDMS membranes. The effect of the average pore size of supports on the performance of composite PDMS membranes was complex, and depended on many factors such as the physico-chemical properties of skin layers or supports and the preparation methods of composite membranes. The total flux of ethanol-water mixture through each composite PDMS membrane increased with increasing temperature. In contrast, the relation between selectivity and temperature was different due to various supports. With increasing feed concentration, the flux through each composite PDMS membrane increased quickly while the selectivity decreased.All these observation would be helpful to provide a guideline for the selection of an optimum support layer.展开更多
A new type of tray called Type-95 tray with a bigger effective mass transfer area and higher tray efficiency is developed and tested, whose downcomer structure is specially designed with a new concept. The fluid dynam...A new type of tray called Type-95 tray with a bigger effective mass transfer area and higher tray efficiency is developed and tested, whose downcomer structure is specially designed with a new concept. The fluid dynamics characteristics of the tray, i.e., pressure drop, weeping, liquid height in the downcomer and flow pattern on the tray, are determined on a test rig with a diameter of 1000 mm by air-water system at atmospheric pressure. The experimental results are compared with those of the traditional sieve tray. It indicates that the Type-95 tray has the advantage of lower pressure drop and bigger flux. The related mathematical equations for designing Type-95 tray are derived from the experimental data, which can be basically applied to the design of an industrial tray within allowable engineering deviation. In addition, the eddy and backmixing of liquid on the tray can be eliminated effectively by installing appropriate deflectors. As a result, the liquid flow pattern on the tray is almost changed into plug flow, which might cause an increase of mass transfer efficiency of the tray.展开更多
文摘The process of removing dilute CO 2 from air by using the mixtures of K 2CO 3 and piperazine (PZ) was conducted in a random packed tower at 25 ℃.The results showed that PZ increased the absorption rate of CO 2 into aqueous K 2CO 3 much more effectively than MEA or DEA. The volumetric overall mass transfer coefficient (K Ga) of dilute CO 2 absorption into K 2CO 3/PZ was measured.The K Ga value was evaluated over the ranges of main operating variables: the concentration of CO 2 in inlet gas, gas flow rate, liquid loading, CO 2 loading in liquid phase,and the concentrations of K 2CO 3 and PZ. The test showed that K Ga could be remarkably improved by increasing liquid loading and the concentration of PZ, and decreasing the concentration of CO 2 in inlet gas, as well as the gas flow rate and CO 2 loading in liquid phase.
文摘Three types of composite PDMS membranes were prepared by using PAN, CA, and PVDF as support materials and used to separate ethanol from aqueous solution by pervaporation.The experimental results evidently demonstrated that the support layer had a significant impact on the flux and selectivity of composite PDMS membranes. The effect of the average pore size of supports on the performance of composite PDMS membranes was complex, and depended on many factors such as the physico-chemical properties of skin layers or supports and the preparation methods of composite membranes. The total flux of ethanol-water mixture through each composite PDMS membrane increased with increasing temperature. In contrast, the relation between selectivity and temperature was different due to various supports. With increasing feed concentration, the flux through each composite PDMS membrane increased quickly while the selectivity decreased.All these observation would be helpful to provide a guideline for the selection of an optimum support layer.
文摘A new type of tray called Type-95 tray with a bigger effective mass transfer area and higher tray efficiency is developed and tested, whose downcomer structure is specially designed with a new concept. The fluid dynamics characteristics of the tray, i.e., pressure drop, weeping, liquid height in the downcomer and flow pattern on the tray, are determined on a test rig with a diameter of 1000 mm by air-water system at atmospheric pressure. The experimental results are compared with those of the traditional sieve tray. It indicates that the Type-95 tray has the advantage of lower pressure drop and bigger flux. The related mathematical equations for designing Type-95 tray are derived from the experimental data, which can be basically applied to the design of an industrial tray within allowable engineering deviation. In addition, the eddy and backmixing of liquid on the tray can be eliminated effectively by installing appropriate deflectors. As a result, the liquid flow pattern on the tray is almost changed into plug flow, which might cause an increase of mass transfer efficiency of the tray.
