scholarly journals Study on Mass Transfer Characteristics of Hydrate-based Gas Absorber

2021 ◽  
Vol 333 ◽  
pp. 04002
Author(s):  
Shun Takano ◽  
Ryosuke Ezure ◽  
Yusuke Takahashi ◽  
Hiroyuki Komatsu ◽  
Kazuaki Yamagiwa ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Gas Separation ◽  
Bubble Column ◽  
Hydrate Formation ◽  
Continuous Operation ◽  
Gas Absorption ◽  
Volumetric Mass Transfer Coefficient ◽  
Type Apparatus

Hydrated-based gas separation is a method capable of selectively separating and recovering greenhouse gases. Although a conventional hydrate-based gas separation apparatus is a batch or a semi-batch system, continuous operation is preferable to increase the throughput of gas without changing the apparatus volume. Recently, we proposed a flow type apparatus to allow continuous operation of hydrate formation (absorption) and subsequent decomposition (desorption). The aim of this study is to investigate the mass transfer characteristics of the continuous apparatus using the HFC134a-N2 mixed gas system. The volumetric mass transfer coefficient was calculated especially during a steady state of gas absorption. Besides, we compared mass transfer performance between the hydrate-based gas absorber and a conventional bubble column. Sodium dodecyl sulfate was used as a hydrate dispersant. In the flow type apparatus, the gas-liquid contact was good and the hydrate slurry state was observed during hydrate formation. In the surfactant solution, the volumetric mass transfer coefficient increased in comparison with that in water. The volumetric mass transfer coefficient with hydrate was higher than that of the bubble column. These results suggest that hydrate formation improves gas absorption performance.

scholarly journals Determination of the ozone volumetric mass transfer coefficient in bubble column with two-fluid nozzle gas distributor

2015 ◽  
Vol 69 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Milica Djekovic-Sevic ◽  
Nevenka Boskovic-Vragolovic ◽  
Ljiljana Takic ◽  
Radmila Garic-Grulovic ◽  
Srdjan Pejanovic
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Bubble Column ◽  
Operating Conditions ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Distributor ◽  
Liquid Mass Transfer ◽  
Two Fluid

Experimental investigation of gas-liquid mass transfer of ozone in water, in bubble column with two-fluid nozzle gas distributor (BKDM), under different operating conditions, are presented in this work. The main objective was to determine the ozone volumetric mass transfer coefficient, kL a, in calm uniform section of the column, under different values of gas and liquid flow rates. Obtained values of these coefficients were compared with the values in countercurrent bubble column. The critical liquid flowrate, when gas hold up reaches its maximum, was experimentally determined. It was shown that the maximum value of the ozone volumetric mass transfer coefficient is obtained just when liquid flowrate is at its critical value.

Influence of Particles and Electrolyte on Gas Hold-Up and Mass Transfer in a Slurry Bubble Column

2006 ◽  
Vol 4 (1) ◽  
Author(s):  
Keshav C Ruthiya ◽  
John van der Schaaf ◽  
Ben F.M. Kuster ◽  
Jaap C Schouten
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Bubble Column ◽  
Bubble Diameter ◽  
Interfacial Area ◽  
Large Bubble ◽  
Volumetric Mass Transfer Coefficient ◽  
Gas Velocity ◽  
Slurry Concentration

In this paper, the influence of carbon and silica particle slurry concentration up to 20 g/l (4 vol%) on regime transition, gas hold-up, and volumetric mass transfer coefficient is studied in a 2-dimensional slurry bubble column. From high speed video image analysis, the average large bubble diameter, the frequency of occurrence of large bubbles, the gas-liquid interfacial area, and the large bubble hold-up are obtained. The liquid side mass transfer coefficient is calculated from the volumetric mass transfer coefficient and the gas-liquid interfacial area. The lyophilic silica particles are rendered lyophobic by a methylation process to study the influence of particle wettability. The influence of organic electrolyte (sodium gluconate) and the combination of electrolyte and particles is also studied. It is found that lyophilic silica, lyophobic silica, and lyophobic carbon particles at concentrations larger than 2 g/l (0.4 vol%) decrease the gas hold-up and shift the regime transition point (where the first large bubbles appear) to a lower gas velocity. The volumetric mass transfer coefficient increases with gas velocity, increases with electrolyte concentration, decreases with slurry concentration, and is higher for lyophobic particles. The liquid side mass transfer coefficient increases with gas velocity, bubble diameter, and is higher for lyophobic particles. A correlation for the mass transfer coefficient based on dimensionless numbers is proposed for the heterogeneous regime.

scholarly journals Mass Transfer Study for Bio-Synergy in Dairy Wastewater Treatment Plant

2018 ◽  
Vol 24 (9) ◽  
pp. 51
Author(s):  
Basma Abbas Abdulmajeed ◽  
Arwa Raad Ibrahim
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Culture Media ◽  
Bubble Column ◽  
Thermal Control ◽  
Dairy Wastewater ◽  
Volumetric Mass Transfer Coefficient ◽  
Bubble Column Bioreactor

The present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal of oxygen is 1.67 min-1 while the volumetric mass transfer coefficient for dissolution the same gas is 3.18 min-1. The same thing occurred with carbon dioxide, where the data showed that the volumetric mass transfer coefficient of the dissolution of CO2 is 0.66 min-1 while the volumetric mass transfer coefficient for removal process is 0.374 min-1. However, the two processes (dissolution and removal) with CO2 take more time than that with O2. Therefore, the production of gases due to metabolic processes in bacteria or microalgae remains in culture’s media for a certain period even if that media is sparged by air. Thus, this will give enough time for both microorganisms to consume those gases. Keywords: Bioreactor, mass transfer, microalgae, aerobic bacteria The present study addresses the behavior of gases in cultivation media as an essential factor to develop the relationship between the microorganisms that are present in the same environment. This relationship was explained via mass transfer of those gases to be a reasonable driving force in changing biological trends. Stripping and dissolution of oxygen and carbon dioxide in water and dairy wastewater were investigated in this study. Bubble column bioreactor under thermal control system was constructed and used for these processes. The experimental results showed that the removal of gases from the culture media requires more time than the dissolution. For example, the volumetric mass transfer coefficient for the removal of oxygen is 1.67 min-1 while the volumetric mass transfer coefficient for dissolution the same gas is 3.18 min-1. The same thing occurred with carbon dioxide, where the data showed that the volumetric mass transfer coefficient of the dissolution of CO2 is 0.66 min-1 while the volumetric mass transfer coefficient for removal process is 0.374 min-1. However, the two processes (dissolution and removal) with CO2 take more time than that with O2. Therefore, the production of gases due to metabolic processes in bacteria or microalgae remains in culture’s media for a certain period even if that media is sparged by air. Thus, this will give enough time for both microorganisms to consume those gases.  

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