Phase change absorbents for CO_(2)are of great interest because they are expected to greatly reduce the heat energy consumption during the regeneration process.Compared with other phase change absorbents,monoethanolam...Phase change absorbents for CO_(2)are of great interest because they are expected to greatly reduce the heat energy consumption during the regeneration process.Compared with other phase change absorbents,monoethanolamine(MEA)-sulfolane-water is inexpensive and has a fast absorption rate.It is one of the most promising solvents for large-scale industrial applications.Therefore,this study investigates the mass transfer performance of this phase change system in the process of CO_(2)absorption in a packed tower.By comparing the phase change absorbent and the ordinary absorbent,it is concluded that the use of MEA/sulfolane phase change absorbent has significantly improved mass transfer efficiency compared to a single MEA absorbent at the same concentration.In the 4 mol·L^(-1)MEA/5 mol·L^(-1)sulfolane system,the CO_(2)loading of the upper liquid phase after phase separation is almost zero,while the volume of the lower liquid phase sent to the desorption operation is about half of the total volume of the absorbent,which greatly reduces the energy consumption.This study also investigates the influence of operating parameters such as lean CO_(2)loading,gas and liquid flow rates,CO_(2)partial pressure,and temperature on the volumetric mass transfer coefficient(K_(G)α_(V)).The research shows that K_(G)α_(V) increases with increasing liquid flow rate and decreases with the increase of lean CO_(2)loading and CO_(2)partial pressure,while the inert gas flow rate and temperature have little effect on K_(G)α_(V).In addition,based on the principle of phase change absorption,a predictive equation for the K_(G)α_(V) of MEA-sulfolane in the packed tower was established.The K_(G)α_(V) obtained from the experiment is consistent with the model prediction,and the absolute average deviation(AAD)is 7.8%.展开更多
A packed tower is one of the components of offshorefloating liquefied natural gas(FLNG)storage and unloading device.In order to ensure the good redistribution performance of a gaseliquid redistributor in the packed towe...A packed tower is one of the components of offshorefloating liquefied natural gas(FLNG)storage and unloading device.In order to ensure the good redistribution performance of a gaseliquid redistributor in the packed tower,we developed a set of experimental devices which can realize different sloshing conditions and different bias current incoming forms and a corresponding numerical calculation model by combining hydraulic experiments with hydromechanic numerical simulation.Then,the simulation results were verified by using the experimental results,and simulation results and experimental results were analyzed.Finally,the performance of the traditional trough plate redistributor was investigated under the working conditions of quiescence,sloshing and different bias current incoming.And the following research results were obtained.First,under the working condition of quiescence,the liquidflow rate of different sprinkling points on the traditional trough plate redistributor is basically the same and the uniform distribution is presented with the non-uniformity in the order of 10e2.Second,the reason for the uniform redistribution deterioration of the redistributor is mainly the liquid level difference caused by the liquid migration.Third,under the working conditions of quiescence,rolling and pitching,the uniform distribution of trough plate redistributor is rarely affected by the change of bias current degree of the incoming liquid.Under the working condition of sloshing 5,the non-uniformity difference of the overall orificeflow rate between the liquid incoming in the whole area and that in 2/3 area is less than 5%.Fourth,the non-uniformity of the overall orificeflow rate in the trough plate redistributor is more affected by rolling and pitching.The non-uniformity of the overall orificeflow rate rises to over 0.5 under the working condition of rolling 5 and over 0.3 in pitching 5.It is indicated that under the working condition of sloshing 5,the uniform distribution of trough plate redistributor is poor not only in the case of whole area liquid incoming but also in the case of bias current incoming,and it is affected more by sea conditions.In conclusion,the traditional trough plate redistributor is poorly adaptive to the sloshing at sea.展开更多
A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving ...A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving method is used to simulate air-cooling tower, and variation of parameters is taken to analyze the data and results of the program.展开更多
Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue...Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue gas.The experiments measured the effects of inlet air temperature, inlet air velocity and circulating water flow rate on the flow and heat transfer. The results show that higher inlet air temperatures and lower inlet air velocities lower the flow resistance and increase the heat transfer coefficient. The stainless steel packing had better surface wettability and larger thermal conductivity than the plastic packing, which enhanced the heat transfer between the water and the saturated moist air. When both the flow resistance reduction and the heat transfer enhancement were considered, the experimental results gave an optimal packing-specific surface area. A packed heat exchanger tower was designed for waste heat recovery from the flue gas of gas-fired boilers based on the experimental results which had better flow and heat transfer characteristics with lower pump and fan power consumption, more stable system operation and less thermal fluctuations compared with a non-packed heat transfer system with atomized water.展开更多
基金The National Natural Science Foundation of China(NSFC-Nos.22138002,22078083,and 21978075)the Hunan Key R&D Program Project(2020NK2015)+2 种基金National Key R&D Projects in Changsha(kh2005018)National Key Research&Development Program-Intergovernmental International Science and Technology Innovation Cooperation Project(2021YFE0112800)the science and technology innovation Program of Hunan Province(2020RC5032)。
文摘Phase change absorbents for CO_(2)are of great interest because they are expected to greatly reduce the heat energy consumption during the regeneration process.Compared with other phase change absorbents,monoethanolamine(MEA)-sulfolane-water is inexpensive and has a fast absorption rate.It is one of the most promising solvents for large-scale industrial applications.Therefore,this study investigates the mass transfer performance of this phase change system in the process of CO_(2)absorption in a packed tower.By comparing the phase change absorbent and the ordinary absorbent,it is concluded that the use of MEA/sulfolane phase change absorbent has significantly improved mass transfer efficiency compared to a single MEA absorbent at the same concentration.In the 4 mol·L^(-1)MEA/5 mol·L^(-1)sulfolane system,the CO_(2)loading of the upper liquid phase after phase separation is almost zero,while the volume of the lower liquid phase sent to the desorption operation is about half of the total volume of the absorbent,which greatly reduces the energy consumption.This study also investigates the influence of operating parameters such as lean CO_(2)loading,gas and liquid flow rates,CO_(2)partial pressure,and temperature on the volumetric mass transfer coefficient(K_(G)α_(V)).The research shows that K_(G)α_(V) increases with increasing liquid flow rate and decreases with the increase of lean CO_(2)loading and CO_(2)partial pressure,while the inert gas flow rate and temperature have little effect on K_(G)α_(V).In addition,based on the principle of phase change absorption,a predictive equation for the K_(G)α_(V) of MEA-sulfolane in the packed tower was established.The K_(G)α_(V) obtained from the experiment is consistent with the model prediction,and the absolute average deviation(AAD)is 7.8%.
基金supported by the Research Project of Ministry of Industry and Information Technology of the People’s Republic of China“Research and Development of Large-scale Columns for Natural Gas Pre-processing”(No.:GXBLZ[2014]495).
文摘A packed tower is one of the components of offshorefloating liquefied natural gas(FLNG)storage and unloading device.In order to ensure the good redistribution performance of a gaseliquid redistributor in the packed tower,we developed a set of experimental devices which can realize different sloshing conditions and different bias current incoming forms and a corresponding numerical calculation model by combining hydraulic experiments with hydromechanic numerical simulation.Then,the simulation results were verified by using the experimental results,and simulation results and experimental results were analyzed.Finally,the performance of the traditional trough plate redistributor was investigated under the working conditions of quiescence,sloshing and different bias current incoming.And the following research results were obtained.First,under the working condition of quiescence,the liquidflow rate of different sprinkling points on the traditional trough plate redistributor is basically the same and the uniform distribution is presented with the non-uniformity in the order of 10e2.Second,the reason for the uniform redistribution deterioration of the redistributor is mainly the liquid level difference caused by the liquid migration.Third,under the working conditions of quiescence,rolling and pitching,the uniform distribution of trough plate redistributor is rarely affected by the change of bias current degree of the incoming liquid.Under the working condition of sloshing 5,the non-uniformity difference of the overall orificeflow rate between the liquid incoming in the whole area and that in 2/3 area is less than 5%.Fourth,the non-uniformity of the overall orificeflow rate in the trough plate redistributor is more affected by rolling and pitching.The non-uniformity of the overall orificeflow rate rises to over 0.5 under the working condition of rolling 5 and over 0.3 in pitching 5.It is indicated that under the working condition of sloshing 5,the uniform distribution of trough plate redistributor is poor not only in the case of whole area liquid incoming but also in the case of bias current incoming,and it is affected more by sea conditions.In conclusion,the traditional trough plate redistributor is poorly adaptive to the sloshing at sea.
文摘A mathematic model for packed air-cooling tower thermodynamic calculation is set up in this paper on the basis of fundamental heat and mass transfer equations. Based on the Double Film theory, direct equation-solving method is used to simulate air-cooling tower, and variation of parameters is taken to analyze the data and results of the program.
基金support extended by the National Basic Research Program of China(2013CB228301)is gratefully acknowledged
文摘Waste heat recovery from the flue gas of gasfired boilers was studied experimentally by measuring the flow and heat transfer of air and water through six kinds of packing with saturated humid air as the simulated flue gas.The experiments measured the effects of inlet air temperature, inlet air velocity and circulating water flow rate on the flow and heat transfer. The results show that higher inlet air temperatures and lower inlet air velocities lower the flow resistance and increase the heat transfer coefficient. The stainless steel packing had better surface wettability and larger thermal conductivity than the plastic packing, which enhanced the heat transfer between the water and the saturated moist air. When both the flow resistance reduction and the heat transfer enhancement were considered, the experimental results gave an optimal packing-specific surface area. A packed heat exchanger tower was designed for waste heat recovery from the flue gas of gas-fired boilers based on the experimental results which had better flow and heat transfer characteristics with lower pump and fan power consumption, more stable system operation and less thermal fluctuations compared with a non-packed heat transfer system with atomized water.
