A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas vel...A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas velocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. The experimental data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional loss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined. The value of total frictional loss coefficient was measured as a function of the cross area of downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data with an average relative error of 9.6%.展开更多
Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-...Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm^2/s(2cs-SiO)and 5.0 mm^2/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern.展开更多
The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments...The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi＇om High EC ＆ Low CR to Low EC ＆ High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values： irradiated by blue and red light-emitting diode lighting with PPFD （photosynthetic photon flux density） value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.展开更多
To enhance the bioregeneration of Fe(II)EDTA and to avoid the inhibition of the components in nitrogen oxides(NOx) scrubbing solution, a novel integrated process of metal chelate absorption and two-stage bioreduction ...To enhance the bioregeneration of Fe(II)EDTA and to avoid the inhibition of the components in nitrogen oxides(NOx) scrubbing solution, a novel integrated process of metal chelate absorption and two-stage bioreduction was developed. In this process, magnetically stabilized fluidized beds(MSFB) were used as the bioreactors, and the phase diagram for the MSFB operation was determined. Factors including inlet NO, O2 and SO2 concentrations, magnetic field intensity, gas flow rate and liquid circulation rate, were studied experimentally to investigate their effects on NO removal. In addition, a mathematical model for NO removal in this integrated system was developed. The results revealed that the integrated system could be steadily operated with a high NO removal efficiency and elimination capacity, even under the condition of high NO and O2 shock-loading. The established model showed that NO removal efficiency was related to the spray column property and the active Fe(II)EDTA concentration, while the latter depends on the bioregeneration of the disabled absorbent in the MSFB.展开更多
基金Supported by Liaoning Provincial Natural Science Foundation(No.972050).
文摘A multi-tube air-lift loop reactor (MT-ALR) is presented in this paper. Based on the energy conservation, a mathematical model describing the liquid circulation flow rate was developed, which was determined by gas velocity, the cross areas of riser and downcomer, gas hold-up and the local frictional loss coefficient. The experimental data indicate that either increase of gas flow rate or reduction of the downcomer diameter contributes to higher liquid circulation rate. The correlation between total and the local frictional loss coefficients was also established.Effects of gas flowrate in two risers and diameter of downcomer on the liquid circulation rate were examined. The value of total frictional loss coefficient was measured as a function of the cross area of downcomer and independent of the gas flow rate. The calculated results of liquid circulation rates agreed well with the experimental data with an average relative error of 9.6%.
基金Supported by the National Natural Science Foundation of China(No.51478297)Program of Introducing Talents of Discipline(No.B13011)
文摘Based on the momentum conservation approach, a theoretical model was developed to predict the superficial liquid velocity, and a correlation equation was established to calculate the gas holdup of an annular external-loop airlift reactor(AELAR)in the bubble flow and developing slug flow pattern. Experiments were performed by using tap-water and silicone oil with the viscosity of 2.0 mm^2/s(2cs-SiO)and 5.0 mm^2/s(5cs-SiO)as liquid phases. The effects of liquid viscosity and flow pattern on the AELAR performance were investigated. The predictions of the proposed model were in good agreement with the experimental results of the AELAR. In addition, the comparison of the experimental results shows that the proposed model has good accuracy and could be used to predict the gas holdup and liquid velocity of an AELAR operating in bubble and developing flow pattern.
文摘The coupling effect of nutrient solution EC （electrical conductivity） levels and CR （circulation rate） on the morphology and quality, in hydroponically grown lettuce was assessed. Lettuce was grown at 5 treatments fi＇om High EC ＆ Low CR to Low EC ＆ High CR. The environmental parameters were controlled in a 20 m^2 plant factory during the hydroponic cultivation with the following values： irradiated by blue and red light-emitting diode lighting with PPFD （photosynthetic photon flux density） value of 150 mol·m^-2·s^-1 for 16 hours per day; Temperature was maintained at 22.0 ℃ during the photoperiod and 16.0 ℃ in dark cycle. The results demonstrate that growing lettuce can be adopted using nutrient solution with lower EC levels and higher CR. The results also indicate that the effect of bi-directional coupled EC and CR resulted in expansion of root length but reducing the root biomass. Nitrate content was significantly reduced.
基金sponsored by the National Natural Science Foundation of China(21077035)the Program for New Century Excellent Talents in the University of China(NCET-11-0851)the Promotion Program for Young and Middle-aged Teacher of Huaqiao University(ZQN-YX104)
文摘To enhance the bioregeneration of Fe(II)EDTA and to avoid the inhibition of the components in nitrogen oxides(NOx) scrubbing solution, a novel integrated process of metal chelate absorption and two-stage bioreduction was developed. In this process, magnetically stabilized fluidized beds(MSFB) were used as the bioreactors, and the phase diagram for the MSFB operation was determined. Factors including inlet NO, O2 and SO2 concentrations, magnetic field intensity, gas flow rate and liquid circulation rate, were studied experimentally to investigate their effects on NO removal. In addition, a mathematical model for NO removal in this integrated system was developed. The results revealed that the integrated system could be steadily operated with a high NO removal efficiency and elimination capacity, even under the condition of high NO and O2 shock-loading. The established model showed that NO removal efficiency was related to the spray column property and the active Fe(II)EDTA concentration, while the latter depends on the bioregeneration of the disabled absorbent in the MSFB.
