The design and operation of radial flow adsorber are crucial in large-scale industrial oxygen production,which necessitate accurate prediction of gas-solid transfer behavior.In this work,a developed Computational Flui...The design and operation of radial flow adsorber are crucial in large-scale industrial oxygen production,which necessitate accurate prediction of gas-solid transfer behavior.In this work,a developed Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)model combined with the adsorption model is proposed.The developed CFD-DEM model is validated by comparing simulated results with experimental data and empirical correlation.Subsequently,the effect of particle packing structure and particle shapes on the dynamic adsorption process are analyzed in detail.The results reveal the mechanism of particle packing structure affecting axial velocity distribution,showing that uneven distribution of resistance on the outer flow channel side leads to uneven axial velocity distribution in the bed.Compared to cylindrical adsorbents,the use of spherical adsorbents results in a more uniform axial velocity distribution,consequently reducing bed pressure drop.The study holds significant potential for optimizing gas distribution and improving separation efficiency in future industrial applications.展开更多
An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly desi...An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.展开更多
This study explored the feasibility of integrating an adsorption and solvent scrubbing process for postcombustion CO_(2) capture from a coal-fired power plant.This integrated process has two stages:the first is a vacu...This study explored the feasibility of integrating an adsorption and solvent scrubbing process for postcombustion CO_(2) capture from a coal-fired power plant.This integrated process has two stages:the first is a vacuum swing adsorption(VSA)process using activated carbon as the adsorbent,and the second stage is a solvent scrubber/stripper system using monoethanolamine (30 wt-%) as the solvent.The results showed that the adsorption process could enrich CO_(2) in the flue gas from 12 to 50 mol-% with a CO_(2) recovery of >90%,and the concentrated CO_(2) stream fed to the solvent scrubber had a significantly lower volumetric flowrate.The increased CO_(2) concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber,bringing the size of the absorber from uneconomically large to readily achievable domain.In addition,the VSA process could also remove most of the oxygen initially existed in the feed gas,alleviating the downstream corrosion and degradation problems in the absorption section.The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO_(2) capture and thus accelerate the deployment of such technologies to reduce carbon emissions.展开更多
In the process of enriching CH4 from coal-bed methane,the separation of CH_(4)/N_(2)is very difficult to accomplish by an adsorption process due to the similar physico-chemical properties of the two molecules.A series...In the process of enriching CH4 from coal-bed methane,the separation of CH_(4)/N_(2)is very difficult to accomplish by an adsorption process due to the similar physico-chemical properties of the two molecules.A series of coconut-shell-based granular activated carbons(GACs)with different pore structures were prepared,which were characterized by different methods.The influence of the pore structure on the separation properties was investigated in detail.The results show that one of the carbons prepared(GAC-3)has high CH4 equilibrium adsorption capacity(3.28 mol·kg–1)at 298 K and equilibrium separation coefficient(3.95).The CH_(4)/N_(2)separation on the GACs is controlled by adsorption equilibrium as compared with the dynamic effect.Taking the specific surface area,for example,the common characterization index of the pore structure is not enough to judge the separation performance of the GACs.However,the microstructure of carbon materials plays a decisive role for CH_(4)/N_(2)separation.According to the pore-structure analysis,the effective pore size for the CH_(4)/N_(2)separation is from 0.4 to 0.9 nm,with the optimum effect occurring in the range of 0.6–0.7 nm,followed by the range of 0.7~0.9 nm.Also,a four-bed vacuum pressure swing adsorption process was adopted to evaluate the performance of GACs for the separation of CH4 from nitrogen.展开更多
In order to solve the water issues when 13X zeolite was applied to capture CO 2 from wet flue gas by vacuum swing adsorption process, multi-layered adsorption system was considered regarding activated alumina F200 and...In order to solve the water issues when 13X zeolite was applied to capture CO 2 from wet flue gas by vacuum swing adsorption process, multi-layered adsorption system was considered regarding activated alumina F200 and silica gel based Sorbead WS as pre-layer materials. LBET (extended Largmuir-BET) model and extended CMMS (cooperative multimolecular sorption) equation were simulated respectively to describe water loading on F200 and Sorbead WS. The two equations can be well added into our in-house simulator to simulate double-layered CO 2 -VSA (vacuum swing adsorption) process. Results indicated that water can be successfully stopped in pre-layers with a good CO 2 capture performance.展开更多
In coal mines in such countries as China and Russia,most of the coal mine methane(CMM) generated during mining is emitted to the atmosphere without any effective usage,because the methane concentration of CMM is relat...In coal mines in such countries as China and Russia,most of the coal mine methane(CMM) generated during mining is emitted to the atmosphere without any effective usage,because the methane concentration of CMM is relatively low and not allowed to be used as fuel for safety reasons.Methane is one of the greenhouse gases.Therefore,if it becomes possible to concentrate CMM to an acceptable level for use as fuel,this will greatly contribute to reduction of greenhouse gas emissions.With the aim of gaining approval as a greenhouse gas emission reduction of the clean development mechanism(CDM) or joint implementation(JI) project,we developed a CMM concentration system to apply the vacuum pressure swing adsorption(VPSA) technology using a high methane-selective adsorbent by Osaka Gas Co.,Ltd.The pilot-scale plant of a CMM concentration system was installed in a coal mine in Fuxin City in the northeastern China and a demonstration test was commenced in December 2008.As the result,the pilot-scale plant successfully concentrated the raw material gas with a methane concentration of 21% and a flow rate of 1000 Nm3/h to 48%,which exceeded the target of the methane concentration performance(a 25% increase).The methane recovery rate reached 93%.展开更多
基金financially supported by the National Key R&D Program of China(grant No.2019YFB1505000).
文摘The design and operation of radial flow adsorber are crucial in large-scale industrial oxygen production,which necessitate accurate prediction of gas-solid transfer behavior.In this work,a developed Computational Fluid Dynamics-Discrete Element Method(CFD-DEM)model combined with the adsorption model is proposed.The developed CFD-DEM model is validated by comparing simulated results with experimental data and empirical correlation.Subsequently,the effect of particle packing structure and particle shapes on the dynamic adsorption process are analyzed in detail.The results reveal the mechanism of particle packing structure affecting axial velocity distribution,showing that uneven distribution of resistance on the outer flow channel side leads to uneven axial velocity distribution in the bed.Compared to cylindrical adsorbents,the use of spherical adsorbents results in a more uniform axial velocity distribution,consequently reducing bed pressure drop.The study holds significant potential for optimizing gas distribution and improving separation efficiency in future industrial applications.
基金financially supported by the Renewable Energy and Hydrogen Projects in National Key Research & Development Program of China (2019YFB1505000)。
文摘An integrated vacuum pressure swing adsorption(VPSA) and Rectisol process is proposed for CO_(2) capture from underground coal gasification(UCG) syngas. A ten-bed VPSA process with silica gel adsorbent is firstly designed to pre-separate and capture 74.57% CO_(2) with a CO_(2) purity of 98.35% from UCG syngas(CH_(4)/CO/CO_(2)/H_(2)/N_(2)= 30.77%/6.15%/44.10%/18.46%/0.52%, mole fraction, from Shaar Lake Mine Field,Xinjiang Province, China) with a feed pressure of 3.5 MPa. Subsequently, the Rectisol process is constructed to furtherly remove and capture the residual CO_(2)remained in light product gas from the VPSA process using cryogenic methanol(233.15 K, 100%(mass)) as absorbent. A final purified gas with CO_(2) concentration lower than 3% and a regenerated CO_(2) product with CO_(2) purity higher than 95% were achieved by using the Rectisol process. Comparisons indicate that the energy consumption is deceased from 2.143 MJ·kg^(-1) of the single Rectisol process to 1.008 MJ·kg^(-1) of the integrated VPSA & Rectisol process, which demonstrated that the deployed VPSA was an energy conservation process for CO_(2) capture from UCG syngas. Additionally, the high-value gas(e.g., CH_(4)) loss can be decreased and the effects of key operating parameters on the process performances were detailed.
基金financial assistance provided to the CO2CRC by the Australian Government through its CRC program and through Australian National Low Emissions Coal Research and Development(ANLEC R&D)supported by Australian Coal Association Low Emissions Technology Limited and the Australian Government through the Clean Energy Initiative。
文摘This study explored the feasibility of integrating an adsorption and solvent scrubbing process for postcombustion CO_(2) capture from a coal-fired power plant.This integrated process has two stages:the first is a vacuum swing adsorption(VSA)process using activated carbon as the adsorbent,and the second stage is a solvent scrubber/stripper system using monoethanolamine (30 wt-%) as the solvent.The results showed that the adsorption process could enrich CO_(2) in the flue gas from 12 to 50 mol-% with a CO_(2) recovery of >90%,and the concentrated CO_(2) stream fed to the solvent scrubber had a significantly lower volumetric flowrate.The increased CO_(2) concentration and reduced feed flow to the absorption section resulted in significant reduction in the diameter of the solvent absorber,bringing the size of the absorber from uneconomically large to readily achievable domain.In addition,the VSA process could also remove most of the oxygen initially existed in the feed gas,alleviating the downstream corrosion and degradation problems in the absorption section.The findings in this work will reduce the technical risks associated with the state-of-the art solvent absorption technology for CO_(2) capture and thus accelerate the deployment of such technologies to reduce carbon emissions.
文摘In the process of enriching CH4 from coal-bed methane,the separation of CH_(4)/N_(2)is very difficult to accomplish by an adsorption process due to the similar physico-chemical properties of the two molecules.A series of coconut-shell-based granular activated carbons(GACs)with different pore structures were prepared,which were characterized by different methods.The influence of the pore structure on the separation properties was investigated in detail.The results show that one of the carbons prepared(GAC-3)has high CH4 equilibrium adsorption capacity(3.28 mol·kg–1)at 298 K and equilibrium separation coefficient(3.95).The CH_(4)/N_(2)separation on the GACs is controlled by adsorption equilibrium as compared with the dynamic effect.Taking the specific surface area,for example,the common characterization index of the pore structure is not enough to judge the separation performance of the GACs.However,the microstructure of carbon materials plays a decisive role for CH_(4)/N_(2)separation.According to the pore-structure analysis,the effective pore size for the CH_(4)/N_(2)separation is from 0.4 to 0.9 nm,with the optimum effect occurring in the range of 0.6–0.7 nm,followed by the range of 0.7~0.9 nm.Also,a four-bed vacuum pressure swing adsorption process was adopted to evaluate the performance of GACs for the separation of CH4 from nitrogen.
基金Supported by the National Natural Science Foundation of China (51074205)Corporate Research Centre for Greenhouse Gas Technology Foundation in Australia
文摘In order to solve the water issues when 13X zeolite was applied to capture CO 2 from wet flue gas by vacuum swing adsorption process, multi-layered adsorption system was considered regarding activated alumina F200 and silica gel based Sorbead WS as pre-layer materials. LBET (extended Largmuir-BET) model and extended CMMS (cooperative multimolecular sorption) equation were simulated respectively to describe water loading on F200 and Sorbead WS. The two equations can be well added into our in-house simulator to simulate double-layered CO 2 -VSA (vacuum swing adsorption) process. Results indicated that water can be successfully stopped in pre-layers with a good CO 2 capture performance.
基金supported by the Project of Development of Methane Concen-tration Technology Aimed at Effective Use of Low-concentration CMM (Coal Methane Gas)the International Research Cooperation Project Implemented by the New Energy and Industrial Technology Development Organizationthe Cooperative Research Project Subsidies from the Ministry of Economy,Trade and Industry
文摘In coal mines in such countries as China and Russia,most of the coal mine methane(CMM) generated during mining is emitted to the atmosphere without any effective usage,because the methane concentration of CMM is relatively low and not allowed to be used as fuel for safety reasons.Methane is one of the greenhouse gases.Therefore,if it becomes possible to concentrate CMM to an acceptable level for use as fuel,this will greatly contribute to reduction of greenhouse gas emissions.With the aim of gaining approval as a greenhouse gas emission reduction of the clean development mechanism(CDM) or joint implementation(JI) project,we developed a CMM concentration system to apply the vacuum pressure swing adsorption(VPSA) technology using a high methane-selective adsorbent by Osaka Gas Co.,Ltd.The pilot-scale plant of a CMM concentration system was installed in a coal mine in Fuxin City in the northeastern China and a demonstration test was commenced in December 2008.As the result,the pilot-scale plant successfully concentrated the raw material gas with a methane concentration of 21% and a flow rate of 1000 Nm3/h to 48%,which exceeded the target of the methane concentration performance(a 25% increase).The methane recovery rate reached 93%.
