Browsing by Author "Su, Fengsheng"

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Adsorption of Carbon Dioxide from Gas Streams via Mesoporous Spherical-Silica Particles
(2010-04-01)
Lu, Chungsying
;
Bai, Hsunling
;
Su, Fengsheng
;
Chen, Wenfa
;
Hwang, Jyh Feng
A relatively new mesoporous silica sorbent for environmental protection applications (i.e., mesoporous spherical-silica particles [MSPs]), was modified by N-[3(trimethoxysilyl)propyl]ethylenediamine (EDA) solution and was tested for its potential in the separation of carbon dioxide (CO(2)) from flue gas. The CO(2) adsorption capacity of MSP and MSP(EDA) increased with temperature from 20 to 60 degrees C but decreased with temperature from 60 to 100 degrees C. The mechanism of CO(2) adsorption on both samples is mainly attributed to physical interaction regardless of temperature change. The MSP(EDA) have good adsorption performance as compared with EDA-modified zeolite or granular activated carbon conducted in this study and many types of silica sorbents reported in the literature. The cyclic CO(2) adsorption showed that spent MSP(EDA) could be effectively regenerated at 120 degrees C for 25 min and CO(2) adsorption capacity of MSP(EDA) was preserved during 16 cycles of adsorption and thermal regeneration. These results suggests that MSP(EDA) are efficient CO(2) sorbents and can be stably used in the prolonged cyclic operation.
Capture of CO(2) from flue gas via multiwalled carbon nanotubes
(2009-04-01)
Su, Fengsheng
;
Lu, Chungsying
;
Cnen, Wenfa
;
Bai, Hsunling
;
Hwang, Jyh Feng
Carbon nanotubes (CNTs) were modified by 3-aminopropyl-triethoxysilane (APTS) solution and were tested for its CO(2) adsorption potential at multiple temperatures (20-100 degrees C). The physicochemical properties of CNTs were changed after the modification, which makes CNTs adsorb more CO(2) gases. The adsorption capacities Of CO(2) via CNTs and CNTs(APTS) decreased with temperature indicating the exothermic nature of adsorption process and increased with water content in air at 0-7%. The mechanism of CO(2) adsorption on CNTs and CNTs(APTS) appears mainly attributable to physical force regardless of temperature change, which makes regeneration of spent CNTs at a relatively low temperature become feasible. The CNTs(APTS) have good adsorption performance Of CO(2) at 20 degrees C as compared to many types of modified carbon or silica adsorbents documented in the literature. This suggests that the CNTs(APTS) are promising low-temperature adsorbents for CO(2) capture from flue gas. (C) 2009 Elsevier B.V. All rights reserved.
Capture of CO2 from flue gas via multiwalled carbon nanotubes
(2009-04-01)
Su, Fengsheng
;
Lu, Chungsying
;
Cnen, Wenfa
;
Bai, Hsunling
;
Hwang, Jyh Feng
Carbon nanotubes (CNTs) were modified by 3-aminopropyl-triethoxysilane (APTS) solution and were tested for its CO2 adsorption potential at multiple temperatures (20-100 degrees C). The physicochemical properties of CNTs were changed after the modification, which makes CNTs adsorb more CO2 gases. The adsorption capacities Of CO2 via CNTs and CNTs(APTS) decreased with temperature indicating the exothermic nature of adsorption process and increased with water content in air at 0-7%. The mechanism of CO2 adsorption on CNTs and CNTs(APTS) appears mainly attributable to physical force regardless of temperature change, which makes regeneration of spent CNTs at a relatively low temperature become feasible. The CNTs(APTS) have good adsorption performance Of CO2 at 20 degrees C as compared to many types of modified carbon or silica adsorbents documented in the literature. This suggests that the CNTs(APTS) are promising low-temperature adsorbents for CO2 capture from flue gas. (C) 2009 Elsevier B.V. All rights reserved.
Comparative study of CO2 capture by carbon nanotubes, activated carbons, and zeolites
(2008-09-01)
Lu, Chungsying
;
Bai, Hsunling
;
Wu, Bilen
;
Su, Fengsheng
;
Fen-Hwang, Jyh
Carbon nanotubes (CNTs), granular activated carbon (GAC), and zeolites were modified by 3-aminopropyltriethoxysilane (APTS) and were selected as adsorbents to study their physicochemical properties and adsorption behaviors Of CO2 from gas streams. The surface nature of these adsorbents was changed after the modification, which make them adsorb more CO2 gases. Under the same conditions, the modified CNTs possess the greatest adsorption capacity of CO2 followed by the modified zeolites and then the modified GAC. The mechanism of CO, adsorption on these adsorbents appears mainly attributable to physical force, which makes, regeneration of spent adsorbents at a relatively low temperature become feasible. The APTS-modified CNTs show good performance Of CO2 adsorption as compared to many types of modified carbon and silica adsorbents reported in the literature. This suooests that the APTS-modified CNTs are efficient CO2 adsorbents and that they possess potential applications for CO2 capture from gas streams.
Pilot-scale production of mesoporous silica-based adsorbent for CO2 capture
(2012-07-01)
Wang, Hou Chuan
;
Lu, Chungsying
;
Bai, Hsunling
;
Hwang, Jyh Feng
;
Lee, Hsiu Hsia
This study presents a pilot-scale spray drying system designed to manufacture spherical mesoporous silica particles (MSP) that is capable of producing up to 100 g per hour. The MSP fabricated via a nozzle pressure of 4 kg/cm(2) and a drying temperature of 200 degrees C possess a high specific area of 1012 m(2)/g, a narrow pore size distribution with an average pore diameter of 2.4 nm, and large pore volume of 0.81 cm(3)/g. They were further modified with a tetraethylenepentamine (TEPA-MSP) to enhance CO2 adsorption selectivity from gas streams. The adsorption capacity of 15% CO2 on TEPA-MSP was significantly influenced by adsorption temperature and water vapor of air streams, and reached a maximum of 87.05 mg/g (1.98 mmol/g) at 60 degrees C and 129.19 mg/g (2.94 mmol/g) at a water vapor of 6.98%. The adsorption capacities and the physicochemical properties of TEPA-MSP were preserved through 20 cycles of adsorption-desorption operation. A comparative study revealed that the TEPA-MSP had better adsorption performance of 15% CO2 than the TEPA-modified granular activated carbon and zeolite. These results suggest that the TEPA-MSP can be stably employed in the prolonged cyclic CO2 adsorption and that they possess good potential for CO2 capture from flue gas. (C) 2012 Elsevier B. V. All rights reserved.
Thermodynamics and regeneration of CO(2) adsorption on mesoporous spherical-silica particles
(2009-12-01)
Lu, Chungsying
;
Su, Fengsheng
;
Hsu, Shih-Chieh
;
Chen, Wenfa
;
Bai, Hsunling
Mesoporous spherical-silica particles (MSPs) were modified by N-[3-(trimethoxysilyl) propyllethylenediamine (EDA) solution and were employed as sorbents to study thermodynamics and regeneration Of CO(2) adsorption from gas streams. The thermodynamic analysis gave low isosteric heats of adsorption, which are typical for physical adsorption. The cyclic CO(2) adsorption on MSP(EDA) showed that the adsorbed CO(2) could be effectively desorbed via thermal treatment at 120 degrees C for 25 min while the adsorbed CO(2) due to physical interaction could be effectively desorbed via vacuum suction at 0.145 bar for 30 min. If a combination of thermal treatment and vacuum suction was conducted at 120 degrees C and 0.145 bar, the time for effectively desorbing CO(2) could be shortened to 7.5 min and thus reduces a significant amount of energy penalty. The adsorption capacities and the physicochemical properties of MSP(EDA) were preserved after 15 cycles of adsorption and regeneration. These results suggest that the MSP(EDA) can be stably employed in the prolonged cyclic adsorption and that they are thus possibly cost-effective sorbents for CO(2) capture from flue gases. (C) 2009 Elsevier B.V. All rights reserved.
Thermodynamics and regeneration of CO2 adsorption on mesoporous spherical-silica particles
(2009-12-01)
Lu, Chungsying
;
Su, Fengsheng
;
Hsu, Shih-Chieh
;
Chen, Wenfa
;
Bai, Hsunling
Mesoporous spherical-silica particles (MSPs) were modified by N-[3-(trimethoxysilyl) propyllethylenediamine (EDA) solution and were employed as sorbents to study thermodynamics and regeneration Of CO2 adsorption from gas streams. The thermodynamic analysis gave low isosteric heats of adsorption, which are typical for physical adsorption. The cyclic CO2 adsorption on MSP(EDA) showed that the adsorbed CO2 could be effectively desorbed via thermal treatment at 120 degrees C for 25 min while the adsorbed CO2 due to physical interaction could be effectively desorbed via vacuum suction at 0.145 bar for 30 min. If a combination of thermal treatment and vacuum suction was conducted at 120 degrees C and 0.145 bar, the time for effectively desorbing CO2 could be shortened to 7.5 min and thus reduces a significant amount of energy penalty. The adsorption capacities and the physicochemical properties of MSP(EDA) were preserved after 15 cycles of adsorption and regeneration. These results suggest that the MSP(EDA) can be stably employed in the prolonged cyclic adsorption and that they are thus possibly cost-effective sorbents for CO2 capture from flue gases. (C) 2009 Elsevier B.V. All rights reserved.