Xuemei Lang

CO2 capture from binary mixture via forming hydrate with the help of tetra-n-butyl ammonium bromide

Abstract Hydrate formation rate and separation effect on the capture of CO 2 from binary mixture via forming hydrate with 5 wt% tetra-n-butyl ammonium bromide (TBAB) solution were studied. The results showed that the induction time was 5 min, and the hydrate formation process finished in 1 h at 4.5 °C and 4.01 MPa. The hydrate formation rate constant reached the maximum of 1.84×10 −7 mol 2 /(s·J) with the feed pressure of 7.30 MPa. The CO 2 recovery was about 45% in the feed pressure range from 4.30 to 7.30 MPa. Under the feed pressure of 4.30 MPa, the maximum separation factor and CO 2 concentration in hydrate phase were 7.3 and 38.2 mol%, respectively. The results demonstrated that TBAB accelerated hydrate formation and enriched CO 2 in hydrate phase under the gentle condition.

Intensification of methane and hydrogen storage in clathrate hydrate and future prospect

Gas hydrate is a new technology for energy gas (methane/hydrogen) storage due to its large capacity of gas storage and safe. But industrial application of hydrate storage process was hindered by some problems. For methane, the main problems are low formation rate and storage capacity, which can be solved by strengthening mass and heat transfer, such as adding additives, stirring, bubbling, etc. One kind of additives can change the equilibrium curve to reduce the formation pressure of methane hydrate, and the other kind of additives is surfactant, which can form micelle with water and increase the interface of water-gas. Dry water has the similar effects on the methane hydrate as surfactant. Additionally, stirring, bubbling, and spraying can increase formation rate and storage capacity due to mass transfer strengthened. Inserting internal or external heat exchange also can improve formation rate because of good heat transfer. For hydrogen, the main difficulties are very high pressure for hydrate formed. Tetrahydrofuran (THF), tetrabutylammonium bromide (TBAB) and tetrabutylammonium fluoride (TBAF) have been proved to be able to decrease the hydrogen hydrate formation pressure significantly.

Clathrate Hydrate Capture of CO2 from Simulated Flue Gas with Cyclopentane/Water Emulsion

Abstract Capture of CO 2 by hydrate is one of the attractive technologies for reducing greenhouse effect. The primary challenges are the large energy consumption, low hydrate formation rate and separation efficiency. This work presents a new method for capture of CO 2 from simulated flue gas [CO 2 (16.60%, by mole)/N 2 binary mixture] by formation of cyclopentane (CP) hydrates at initial temperature of 8.1 °C with the feed pressures from 2.49 to 3.95 MPa. The effect of cyclopentane and cyclopentane/water emulsion on the hydrate formation rate and CO 2 separation efficiency was studied in a 1000 ml stirred reactor. The results showed the hydrate formation rate could be increased remarkably with cyclopentane/water emulsion. CO 2 could be enriched to 43.97% (by mole) and 35.29% (by mole) from simulated flue gas with cyclopentane and cyclopentane/water (O/W) emulsion, respectively, by one stage hydrate separation under low feed pressure. CO 2 separation factor with cyclopentane was 6.18, higher than that with cyclopentane/water emulsion (4.01), in the range of the feed pressure. The results demonstrated that cyclopentane/water emulsion is a good additive for efficient hydrate capture of CO 2 .

Hydrate capture CO2 from shifted synthesis gas, flue gas and sour natural gas or biogas

CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However, rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas (CO2/CH4 system), the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas.

Economic Comparison of Three Gas Separation Technologies for CO2 Capture from Power Plant Flue Gas

Abstract Three gas separation technologies, chemical absorption, membrane separation and pressure swing adsorption, are usually applied for CO 2 capture from flue gas in coal-fired power plants. In this work, the costs of the three technologies are analyzed and compared. The cost for chemical absorption is mainly from

Pectin as an Extraordinary Natural Kinetic Hydrate Inhibitor.

30 to

Comparative evaluation of thermal oxidative decomposition for oil-plant residues via thermogravimetric analysis: Thermal conversion characteristics, kinetics, and thermodynamics

60 per ton (based on CO 2 avoided), while the minimum value is

Evaluation of agricultural residues pyrolysis under non-isothermal conditions: Thermal behaviors, kinetics, and thermodynamics

10 per ton (based on CO 2 avoided). As for membrane separation and pressure swing adsorption, the costs are

Accelerated nucleation of tetrahydrofuran (THF) hydrate in presence of ZIF-61

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Promoting effect of super absorbent polymer on hydrate formation

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