Experimental Research on Effects of Diffuser and Mixing Chamber on Liquid-Gas Ejector Driven by Aqueous LiBr Solution

2012 ◽  
Vol 512-515 ◽  
pp. 2226-2230
Author(s):  
Hong Tao Gao ◽  
Rui Wang ◽  
Ling Deng
Keyword(s):  
Mass Transfer ◽  
Optimal Design ◽  
Experimental Research ◽  
Cooling Capacity ◽  
Experimental Performance ◽  
Mass Transfer Efficiency ◽  
Libr Solution ◽  
Mixing Chamber ◽  
Absorption Refrigerator ◽  
Improve Mass Transfer

From the standpoint of offering reference for its optimal design, liquid-gas ejector is applied to absorption refrigerator in order to improve mass transfer efficiency. The experimental performance of ejector driven by aqueous LiBr solution was investigated. The experimental results indicate that the diffuser with larger diameter of throat could improve the system cooling capacity while reducing the volume of absorber; the larger diameter of the mixing chamber could improve the cooling capacity, but the extent of improvement is little and the required absorber volume per kW of cooling capacity greatly is increased.

scholarly journals Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Luis Huezo ◽  
Ajay Shah ◽  
Frederick Michel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Transfer ◽  
Glucose Uptake ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Inhibitory Effects ◽  
Negative Effects ◽  
Intraparticle Mass Transfer ◽  
Improve Mass Transfer

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

Effect of Nanoparticles on H2O/LiBr Falling Film Absorption Process

2016 ◽  
Author(s):  
L. Y. Zhang ◽  
Y. Li ◽  
Y. Wang ◽  
L. X. Cao ◽  
X. Z. Meng
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Fe3o4 Nanoparticles ◽  
Falling Film ◽  
Absorption Process ◽  
Nanoparticle Concentration ◽  
Water Vapor Absorption ◽  
Libr Solution ◽  
Falling Film Absorption ◽  
Film Absorption

Absorber is an important component in absorption refrigerating system. Its performance plays a significant role on the overall efficiency of absorption refrigerating system. The nanofluids which can enhance the heat and mass transfer will be utilized to absorber for enhancing the water vapor absorption process and improving the absorber efficiency. The software CFD-FLUENT is used to analyze the falling film absorption process of the nanofluids, which consists of H2O/LiBr solution with Fe3O4 nanoparticles in this paper. The results indicate that the enhancing heat and mass transfer of nanofluids is related to the nanoparticle concentration and size. The stronger the nanoparticle concentration, the greater enhancement of heat and mass transfer of falling film; while the smaller the nanoparticle size, the greater enhancement of heat and mass transfer of falling film. It is also found that the enhancement ratio of heat and mass transfer flux reach 1.48 and 1.37, respectively, as the Fe3O4 nanoparticles mass concentration of 0.01wt% and the size of 50nm.

scholarly journals Circulating Jet for Enhancing the Mass Transfer in a Gas-liquid Stirred Tank Reactor

2021 ◽  
Author(s):  
Lei Wang ◽  
Xiao Xu ◽  
Hualin Wang ◽  
HongLai Liu ◽  
Qiang Yang
Keyword(s):  
Mass Transfer ◽  
Scale Up ◽  
Input Power ◽  
Stirred Tank ◽  
Exhaust Gas ◽  
Stirred Tank Reactor ◽  
Tank Reactor ◽  
Mass Transfer Efficiency ◽  
Low Mass ◽  
Liquid Mass Transfer

A gas-liquid stirred tank reactor (STR) has some problems, such as low mass transfer efficiency, high exhaust gas oxygen concentration, and low product conversion rate, due to limitations of stirring speed and input power. This article proposes a method to enhance the gas-liquid mass transfer in a STR using circulating jet internals. When a circulating jet is added, the average bubble size in the reactor is reduced to 1.26 mm, and the overall gas holdup is increased to 8.23%, which is an increase of 3.62 times of the original STR. The gas-liquid volumetric mass transfer coefficient is increased to 0.05556 s-1, which is 4.84 times of the original STR. The unit volume power is increased by only 1.4 times. These data provide references for the design and scale-up of new jet STRs.

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