Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Xingbo Wang,Yibo Pan,Weidong Fan,Hao Guo,Hai Zhang
Municipal solid waste incineration (MSWI), a promising technology for managing MSWI capacity, has a large amount of CO 2 in its flue gas emissions, but lacks effective means of carbon reduction. Modification of CaO-based sorbents using fly ash, a solid waste from coal-fired power plants, is a potential application to improve CO 2 capture capacity. In this study, a cost-effective fly ash-CaO sorbent was developed by combining high-calcium and high-magnesium fly ash with CaO by hydration. The CO 2 capture capacity and carbonation conversion of fly ash-CaO sorbents were investigated at different temperatures, CO 2 partial pressures and doping ratios in a calcination/carbonation reaction system. Optimum carbonation reaction temperature (760℃) for CaO and optimum calcination temperature (850℃) for fly ash were obtained. In the experiment of CaO doped with fly ash, the novel sorbents prepared by CaO doped with fly ash at a mass ratio of 3:1 had the highest carbonation conversion (98.88 %). The hydration reaction promoted the transformation of CaO to Ca(OH) 2 , which improved the CO 2 capture capacity of the sorbents. The inert materials (Al 2 O 3 , SiO 2 ) in the fly ash were uniformly distributed as structural skeleton in the sorbents, enhancing the structural stability and anti-sintering ability. The S element contained in the fly ash competes with CO 2 for adsorption sites and produces stable CaSO 4 , which reduces the carbon capture capacity of the sorbents. A unique mineralization sequestration process for MSWI carbon capture is proposed that is economical and industrially viable. A promising route to improve CO 2 capture performance with waste reutilization is emphasized.
研究领域:
环境科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Xingbo Wang,Yibo Pan,Weidong Fan,Hao Guo,Hai Zhang
CaO-based sorbents are among the most promising materials for capturing CO 2 from high-temperature flue gas in coal-fired power plants. Fly ash, a solid waste product generated by coal-fired power plants, can be utilized as a calcium source for the in-situ preparation of CaO-based sorbents to capture CO 2 from high-temperature flue gas. Nevertheless, the inherent characteristics of fly ash, such as its low adsorption capacity and poor activity, present challenges in its utilization. Doping is an effective method for enhancing the adsorption capacity and activity of sorbents. In this study, fly ash-CaO sorbents were doped and hydrated with six common chlorides and hydroxides in order to investigate the potential effects of the dopants on the sorbents. The carbonation performance of these sorbents was evaluated in a calcination/carbonation reaction system, and the modified sorbents were characterized using multiple methods to elucidate the underlying mechanisms. The results indicate that the carbonation conversion of the six modified sorbents is in the order of Fe(OH) 3 / Fe(Cl) 3 > KCl > NaCl > KOH>NaOH. The element enhancement of the modified sorbents at the same doping ratio is in the order of Fe 3+ > K + > Na + , and Cl − exhibit better synergistic effects with K + and Na + compared to OH − . Some dopants improve the carbonation reaction kinetics of the sorbents, promoting the overall reaction shift towards the rapid reaction stage. This study provides a promising pathway for the reuse of solid waste fly ash and the development of CaO-based sorbents suitable for rapid reaction scenarios.
研究领域:
能源与环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2016
·
IF 2.835
Pengfei Zhao,Ji Sun,Yimin Li,Ke Wang,Zeguang Yin,Zhongyun Zhou,Zhen Su
A facile carbon template method was employed to modify the microstructure of calcined organometallic calcium compounds (i.e., calcium acetate, calcium citrate, and calcium gluconate) for high-temperature CO2 capture. The effects of the decomposition atmosphere, carbon source, and pyrolysis temperature on the physical and chemical properties as well as the cyclic CO2 capture performance were determined using various morphological characterization techniques and detailed thermogravimetric analysis. During pyrolysis in an inert atmosphere, in situ carbon formed from organometallic calcium compounds, which served as a template for controlling the sintering of CaCO3, and the subsequent carbon burnoff in air promoted the fabrication of porous CaO. Among the three organometallic calcium compounds, the pyrolysis process of calcium gluconate exhibited the earliest carbonization and the template with the highest organic carbon content and the slowest decomposition of CaCO3. Therefore, the most favorable structure (i.e., the smallest crystal size, largest specific surface area, and largest pore volume of CaO) was obtained from calcium gluconate, which was responsible for the fastest adsorption rate, highest capacity, and best stability. Moreover, this superior performance was maintained when the pyrolysis temperature was approximately 600–800 °C.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 15
·9173-9182
·
IF 10.733
Ke Wang,Peter T. Clough,Pengfei Zhao,Edward J. Anthony
Calcium looping, a promising high-temperature CO2 capture technique, offers a mid-term economic solution to mitigate anthropogenic CO2 emissions. The main challenge in calcium looping is the synthesis of highly efficient CaO-based sorbents that can be used over many reaction cycles. Here, a sacrificial N-doped carbon nanosheet template was developed which produces MgO-stabilized CaO sorbents with fast adsorption rates, high capacities and remarkable long-term performance over many cycles. The characterization results show that such a template was formed through in situ pyrolysis of an organic acid and nitrates in a simple heating process in nitrogen. The presence of a carbonaceous template prevented crystallite growth, featured highly macroporous nanosheet (∼60 nm thick) morphologies, and ensured homogeneous mixing of Ca and Mg, which are essential to minimize diffusion limitations, mitigate sintering, and provide structural stability. Thus, 10 mol% MgO acting as an inert stabilizer was sufficient to achieve a CO2 uptake of 0.65 g g−1 (corresponding to a capacity retention of 89.9%) after 10 cycles under realistic conditions, as confirmed by TGA analysis. This N-doped carbon template can be applied generally to produce a wide range of porous and nanostructured stabilized CaO sorbents with stable CO2 uptake.
研究领域:
化学工程
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材料科学
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环境科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）