Separations
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2024
·Vol. 11
·期 1
·20
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IF 2.5
Wenxia Xie,Chunmin Tu,Jun Zhang,Chengwei Xu
The accumulation of uncollected fly ash from flue gas in post-combustion CO2capture processes is a significant concern in current coal-fired power plants due to its potential impact on the performance of CO2absorbent and absorption towers. In order to determine the effect of fly ash on the mass transfer performance of CO2absorption into monoethanolamine (MEA) and diethanolamine (DEA) aqueous solutions, experimental studies were carried out using a small-sized packed tower equipped with θ-ring random packing. These studies were conducted under various operating parameters, including solution temperature, liquid/gas ratio (L/G), packing height, and fly ash concentration. The results show that the effect of fly ash on the outlet CO2concentration was primarily observed during the initial stages of the experimental process. Moreover, the presence of fly ash leads to a reduction in the volumetric overall mass transfer coefficient (KGav) when using MEA and DEA solution, and increasing the fly ash concentration further exacerbates this negative impact. However, the effect of fly ash on the reduction inKGavis not significantly related to its chemical composition but rather depends on the operational parameters. With increasing solution temperature, liquid/gas ratio (L/G), and packing height, theKGavvalues for different solutions exhibit an upward trend. The negative effect of fly ash onKGavremains relatively stable for MEA as solution temperature and packing height increase. Compared to MEA, fly ash has a greater negative effect on DEA solution under the same experimental conditions. The analysis reveals that the detrimental effect of fly ash onKGavprimarily stems from its ability to alter the distribution state of the absorption liquid within the packed tower.
研究领域:
环境工程
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化学工程
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产品关联
DOI
高影响因子
APPLIED ENERGY
·
2024
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IF 10.1
Yingjie Niu,Ting Li,Ali Hassan Bhatti,Jiaqi Qu,Xin Zhou,Li Luo,Francesco Barzagli,Chao'en Li,Rui Zhang
The use of solid acid catalysts for sorbent regeneration is an emerging approach to improve the energy efficiency of CO 2 capture processes. In this study, fly ash (FA), an industrial byproduct rich in acid/base sites, was chosen as a support material for the solid acid SO 4 2− /ZrO 2 (SZ) in the preparation of SZ@FA composite catalysts. Three catalysts with different mass ratios between SZ and FA were synthesized and evaluated in the regeneration process at 88 °C of a CO 2 -saturated MEA solution. Their desorption performance, expressed as CO 2 desorption rate, amount of CO 2 desorbed , and heat duty, was then compared with that obtained with unmodified FA, ZrO 2, and in the absence of catalysts (blank), under identical operating conditions. Compared to the uncatalyzed system, the SZ@FA composite catalysts showed significantly better desorption performance. In particular, SZ@FA-1/2 provided the highest values of desorption rate and cyclic capacity while reducing energy consumption by 45.4% compared to the blank system. It also demonstrated stability over 20 consecutive absorption-desorption cycles. Comparison with other reported catalysts highlighted the high performance of SZ@FA-1/2, particularly in terms of relative heat duty reduction, positioning it as a cost-effective and environmentally friendly choice for post-combustion capture applications.
研究领域:
化学工程
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环境科学
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DOI
高影响因子
AICHE JOURNAL
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2018
·Vol. 64
·期 11
·3988-4001
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IF 3.326
Xiaowen Zhang,Jieling Hong,Helei Liu,Xiao Luo,Wilfred Olson,Paitoon Tontiwachwuthikul,Zhiwu Liang
In this work, the composite catalysts, SO 4 2 /ZrO 2 /γ-Al 2 O 3 (SZA), with different ZrO 2 and γ-Al 2 O 3 mass ratios were prepared and used for the first time for the carbon dioxide (CO 2 )-loaded monoethanolamine (MEA) solvent regeneration process to reduce the heat duty. The regeneration characteristics with five catalysts (three SZA catalysts and two parent catalysts) of a 5 M MEA solution with an initial CO 2 loading of 0.5 mol CO 2 /mol amine at 98°C were investigated in terms of CO 2 desorption performance and compared with those of a blank test. All the catalysts were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, N 2 adsorption–desorption experiment, ammonia temperature programmed desorption, and pyridine-adsorption infrared spectroscopy. The results indicate that the SZA catalysts exhibited superior catalytic activity to the parent catalysts. A possible catalytic mechanism for the CO 2 desorption process over SZA catalyst was proposed. The results reveal that SZA1/1, which possesses the highest joint value of Brφnsted acid sites (BASs) and mesopore surface area (MSA), presented the highest catalytic performance, decreasing the heat duty by 36.9% as compared to the catalyst-free run. The SZA1/1 catalyst shows the best catalytic performance as compared with the reported catalyst for this purpose. Moreover, the SZA catalyst has advantages of low cost, good cyclic stability, easy regeneration and has no effect on the CO 2 absorption performance of MEA. © 2018 American Institute of Chemical Engineers AIChE J , 64: 3988–4001, 2018
研究领域:
化学工程
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催化材料
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环境科学
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DOI
高影响因子
RSC Advances
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2018
·Vol. 8
·期 4
·1987-1992
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IF 2.936
Mei Wang,Mingming Wang,Na Rao,Jiale Li,Jianfen Li
Alcohol amine solutions have a high absorption capacity and rate for CO2 capture, however, there are some shortcomings such as high energy-consumption and low stability. To enhance CO2 capture performance of aqueous MEA, a functional ionic liquid ([NH2e-mim][BF4]) was introduced based on the advantages for CO2 capture. Absorbents were prepared with the molar concentration ratio of [NH2e-mim][BF4] to the 30 vol% aqueous MEA of 0 : 10, 1 : 9, 2 : 8, 3 : 7, 4 : 6 and 6 : 4. The density and the viscosity of the investigated absorbents were measured and the effects of the molar fraction of [NH2e-mim][BF4] (nI) and temperature on CO2 absorption performance were investigated. CO2 desorption performance of the solvent at different temperatures was discussed. The stability performance of the absorbent with nI of 2 : 8 (I/M2:8) was examined by five consecutive cyclic tests. The results showed that for pure CO2, the I/M2:8 displayed the highest absorption performance at 303 K under 1 bar: a comparable CO2 absorption capacity of the 30 vol% aqueous MEA and a higher CO2 absorption rate at the later absorption stage. Moreover, with the increase of temperature, CO2 absorption capacity and rate decreased, while CO2 desorption efficiency and rate increased. 393 K was chosen as the optimum desorption temperature with the desorption efficiency of 99.31%. The introducing of IL contributed to CO2 desorption performance of the absorbents significantly. The properties (CO2 absorption capacity, mass loss, density and viscosity) of the I/M2:8 during the cycles suggested that the IL-MEA mixture had an excellent stability performance.
研究领域:
化学工程
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环境科学
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DOI
PubMed
高影响因子
Greenhouse Gases-Science and Technology
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2019
·Vol. 9
·期 3
·553-566
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IF 1.693
Menglong Liu,Siyang Tang,Kui Ma,Changjun Liu,Hairong Yue,Bin Liang
Monoethanolamine (MEA) solution has been used widely in the post-combustion CO 2 capture process; however, the high heat duty and reaction temperature (e.g. 125°C) for MEA regeneration leads to a high energy requirement (nearly 70–80% of the total running cost). We report the use of solid particles (H-Zeolite Socony Mobile-5 (HZSM-5), quartz, and activated carbon) to facilitate the mass transfer of CO 2 bubble nucleation and enhance the CO 2 desorption rate. The results show that the mass transfer of CO 2 from liquid phase to gas phase is the rate-determining step, rather than the chemical reaction. The addition of HZSM-5 particles in the solution significantly enhanced CO 2 bubble nucleation by providing nucleation sites and gas cavities, leading to an average CO 2 desorption rate enhancement of 43.2%, and an energy consumption reduction of 23.3%. This process also operated at ∼95°C, which is a much lower temperature than that used in the commercial process and is feasible for industrial applications. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.
研究领域:
化学工程
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环境科学
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DOI
高影响因子
APPLIED ENERGY
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2017
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IF 7.182
Xiaowen Zhang,Xin Zhang,Helei Liu,Wensheng Li,Min Xiao,Hongxia Gao,Zhiwu Liang
In this work, the regeneration of rich CO 2 -loaded monoethanolamine (MEA) solvent with two catalysts (e.g. SAPO-34 and SO 4 2− /TiO 2 ) was investigated in order to reduce the energy requirement for solvent regeneration. The regeneration behavior with and without catalyst of a 5M MEA solution with an initial CO 2 loading of 0.5 mol CO 2 /mol amine at 96 °C was studied to compare their CO 2 desorption rate and heat duties. The results show that the two solid acid catalysts can reduce the heat duty for solvent regeneration and increase the CO 2 desorption rate in comparison with blank test. The mechanism of CO 2 desorption with catalyst in 5M MEA was proposed based on the result of catalyst characterization (e.g. N 2 absorption/desorption experiment, Py-IR, NH 3 -TPD, FT-IR and XRD) to better understand the desorption process. The results indicate that SAPO-34 with the higher joint value of Brϕnsted/Lewis acid sites ratio (B/L) and mesopore surface area (MSA) shows the faster CO 2 desorption rate and lower heat duty than SO 4 2− /TiO 2 . Based on the experimental results, the addition of solid acid catalysts into amine solution could be considered as one of choices to reduce the heat duty for CO 2 desorption from CO 2 -loaded amine solvent.
研究领域:
化学工程
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环境科学
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催化
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2024
·
IF 13.3
Yao Shen,Ke Wang,Lu Li,Jingkai Zhao,Jiexu Ye,Ping Chen,Xiang Gao,Shihan Zhang
Catalyst-aided CO 2 desorption offers a promising reduction in the energy penalty of amine scrubbing, but faces the challenges of slow mass transfer, sluggish desorption kinetics, and susceptibility to deactivation. In this work, a hollow composite catalyst C@ZrO 2 was developed to simultaneously realize rapid electron, proton and mass transfer for CO 2 desorption via facilitating proton-coupled electron transfer (PCET) effect. The CO 2 desorption rate of benchmark MEA solution increased by 126% and relative heat duty decreased by 69.9% in presence of C@ZrO 2 , and its catalytic performance didn’t noticeably decline after 10 cycles. Additionally, the desorption rate of biphasic solvents with a high viscosity increased by 112% and relative heat duty decreased by 57.3% with C@ZrO 2 . Based on theoretical calculation, the facilitated PCET efficiency of carbon layer increased the binding energy of carbamate to enhance its mass transfer rate from the liquid phase to the C@ZrO 2 surface, and stretched the C-N bond to reduce the proton transfer energy barrier by 66.8%. This work provided a novel insight to design catalysts for energy-efficient and stable CO 2 capture.
研究领域:
化学工程
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催化材料
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环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）