A novel heat-integrated distillation scheme on pilot scale for producing C5 foaming agent, a mixture of isopentane and pentane in a certain proportion, was proposed with the aid of process simulation. Compared with th...A novel heat-integrated distillation scheme on pilot scale for producing C5 foaming agent, a mixture of isopentane and pentane in a certain proportion, was proposed with the aid of process simulation. Compared with the conventional distillation scheme, C5 foaming agent was directly separated at the top of the original isopentane or pentane column in the novel scheme, instead of first refining the two isomerides to high purities and then mixing them into final products. This improvement reduced the difficulty of the separation and avoided meaningless exergy loss caused by re-mixing, which finally contributed to an energy-efficient design by a big margin. Moreover, the column grand composite curves(CGCCs)were used to modify all distillation columns, indicating that there is potential to improve the energy efficiency further. Therefore, double-effect, or heat-integrated distillation was also adopted. Energy and exergy analyses were then conducted to evaluate the effectiveness of the proposed scheme for the purpose of energy saving. The simulation results of the conventional distillation scheme were in agreement with its on-site counterpart. Analyses showed that the novel heat-integrated scheme reduced hot utility by 27.12%,, cold utility by 24.49%,, and total exergy loss by 23.95%,.展开更多
The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these t...The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these two devices was investigated.Experimental results indicated that the second device could significantly reduce the liquid fraction of the foam leaving the column,εout,leading to a higher enrichment of the out-flow stream.As its mounting height increased from 0 to 15 cm,εout declined from 7.07‰ to 6.13 ‰ and the maximum nisin activity in the foamate could reach 39.6 IU/μL.The slight increase in nisin inactivation rate indicated the applicability of this method in the recovery and concentration of proteins.Finally,the mechanism of the process was primarily explained by invoking recent work on pneumatic foams.This research provides a basis for the design of multistage draining foam fractionator which could potentially be an effective separation equipment.展开更多
In the present study, pool boiling heat transfer performance and bubble behaviors of hybrid structures with metal foam and square column are investigated by lattice Boltzmann method. By using the vapor-liquid phase ch...In the present study, pool boiling heat transfer performance and bubble behaviors of hybrid structures with metal foam and square column are investigated by lattice Boltzmann method. By using the vapor-liquid phase change model of Gong-Cheng and Peng-Robinson equation of state, the effects of structural parameters, including metal foam thickness, porosity, column height and ratio of column width(W) to gap spacing(D) are investigated in details. The results show that hybrid structure performs better than pure columnar structure in pool boiling heat transfer. The hybrid structure accelerates bubble growth by fluid disturbance while metal skeletons prevent the bubble escaping. The optimum ratio of column width to gap spacing decreases with the increase of heat flux and HTC(heat transfer coefficient) can achieve an increase up to 25% when W/D change from 5/3 to 1/3. The increase of column height enhances heat transfer by expanding surface area and providing space for bubble motion. The metal foam thickness and porosity have a little influence on pool boiling heat transfer performance, but they have an important effect on bubble motion in the regime.展开更多
基金Supported by the Program of Introduction of Talents of Discipline to Universities(B06006)
文摘A novel heat-integrated distillation scheme on pilot scale for producing C5 foaming agent, a mixture of isopentane and pentane in a certain proportion, was proposed with the aid of process simulation. Compared with the conventional distillation scheme, C5 foaming agent was directly separated at the top of the original isopentane or pentane column in the novel scheme, instead of first refining the two isomerides to high purities and then mixing them into final products. This improvement reduced the difficulty of the separation and avoided meaningless exergy loss caused by re-mixing, which finally contributed to an energy-efficient design by a big margin. Moreover, the column grand composite curves(CGCCs)were used to modify all distillation columns, indicating that there is potential to improve the energy efficiency further. Therefore, double-effect, or heat-integrated distillation was also adopted. Energy and exergy analyses were then conducted to evaluate the effectiveness of the proposed scheme for the purpose of energy saving. The simulation results of the conventional distillation scheme were in agreement with its on-site counterpart. Analyses showed that the novel heat-integrated scheme reduced hot utility by 27.12%,, cold utility by 24.49%,, and total exergy loss by 23.95%,.
基金supported by Natural Science Foundation of Tianjin (Grant No. 08JCZDJC25200)Natural Science Research Program of Hebei Province (Grant No. Z2008310)
文摘The foam fractionation of nisin from its fermentation broth was studied.Two types of devices consisting of a rubber piston and a foam riser were developed to enhance foam drainage.The separation performance of these two devices was investigated.Experimental results indicated that the second device could significantly reduce the liquid fraction of the foam leaving the column,εout,leading to a higher enrichment of the out-flow stream.As its mounting height increased from 0 to 15 cm,εout declined from 7.07‰ to 6.13 ‰ and the maximum nisin activity in the foamate could reach 39.6 IU/μL.The slight increase in nisin inactivation rate indicated the applicability of this method in the recovery and concentration of proteins.Finally,the mechanism of the process was primarily explained by invoking recent work on pneumatic foams.This research provides a basis for the design of multistage draining foam fractionator which could potentially be an effective separation equipment.
基金supported by the National Natural Science Foundation of China(Grant No.52276075)。
文摘In the present study, pool boiling heat transfer performance and bubble behaviors of hybrid structures with metal foam and square column are investigated by lattice Boltzmann method. By using the vapor-liquid phase change model of Gong-Cheng and Peng-Robinson equation of state, the effects of structural parameters, including metal foam thickness, porosity, column height and ratio of column width(W) to gap spacing(D) are investigated in details. The results show that hybrid structure performs better than pure columnar structure in pool boiling heat transfer. The hybrid structure accelerates bubble growth by fluid disturbance while metal skeletons prevent the bubble escaping. The optimum ratio of column width to gap spacing decreases with the increase of heat flux and HTC(heat transfer coefficient) can achieve an increase up to 25% when W/D change from 5/3 to 1/3. The increase of column height enhances heat transfer by expanding surface area and providing space for bubble motion. The metal foam thickness and porosity have a little influence on pool boiling heat transfer performance, but they have an important effect on bubble motion in the regime.
