FUEL PROCESSING TECHNOLOGY
·
2020
·
IF 4.982
Yue Cao,Bing Song,Min Song,Fanyue Meng,Yuexing Wei,Qi Cao
Arsenic with high volatility and toxicity is usually generated during coal combustion and the capture of arsenic is restrained at high temperature since the sintering of adsorbents. Therefore, it is necessary to develop an adsorbent with sintering resistance for the arsenic removal at high temperature. In the study, the arsenic vapor capture by CaSiO 3 , CaO and SiO 2 was carried out in the flue gas with/without SO 2 and NO at high temperatures from 1000 °C to 1200 °C. The results showed that CaSiO 3 exhibited excellent arsenic capture with the capacity of 4.98 mg/g and the capture efficiency was increased with the temperature increasing. The effect of acid gases was also considered. A certain amount of CaSO 4 with poor capture performance was formed on CaSiO 3 surface in the presence of SO 2 , leading to the decrease of the amount of arsenic captured. On the other hand, the effect of NO was not obvious as SO 2 . Although arsenic capture was suppressed when introduced SO 2 and NO, it still remained considerable arsenic capture for the CaSiO 3 adsorbent. Additionally, the pivotal role of O 2 was also studied. Taking into account the high capture capacity and excellent anti-sintering property, CaSiO 3 was a good adsorbent suitable for the removal of arsenic from coal combustion flue gas.
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
FUEL
·
2021
·
IF 6.609
Yong Wei,Guijian Liu,Biao Fu,Yuan Liu,Xuan Xue
Fine particulate matter (PM) emitted from coal-fired power plants (CFPPs) has aroused widespread environmental and human health concerns. Cadmium (Cd), as one of the prime toxic air pollutants, which exists in fine PM intensifies its toxicity. In this research, three particle sizes of PM (PM 1 , PM 2.5 , and PM 10 ) at the outlet of electrostatic precipitator (ESP), along with feed coal, bottom ash, and ESP ash, were collected from a 300-MW pulverized CFPP. Results showed that Cd was more enriched in the fly ash than in bottom ash. With the PM diameter decreasing, the relative enrichment index (REI) value of Cd increases from 2.30 to 7.84. The concentration of Cd was found to be intimately related to Ti in the PM. Abundant Ti-rich particles were identified in the PM 1 , having quite different chemical compositions as compared to particles larger than 2.5 μm. The major processes governing the formation of Ti-rich particles included melting of silicate-bound Ti and heterogeneous condensation of gaseous Ti from the decomposition of organic-associated Ti in coal. The transformation behavior of Cd to PM in a coal combustion process was discussed based on its occurrence mode in coal, thermodynamic property, and the possible interactions with ash particle compositions. The retention of Cd (g) by Ti-rich particle were probably dominated by chemisorption at high temperature; at lower temperature, physical adsorption or condensation may be the primary mechanisms for capturing CdCl 2 (g).
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Yiquan Guo,Junying Zhang,Yongchun Zhao,Shaolong Wang,Cheng Jiang,Chuguang Zheng
Fly ash fine particles emitted from coal-fired power plants are the primary atmospheric pollutant in China. The pressure, temperature, and velocity distribution of the flow field in a chamber was simulated to evaluate chemical agglomeration. The effect on the removal efficiency of composition, concentration, pH, K + content, and zeta potential of the chemical agglomeration solutions as well as surfactant and flue gas temperature were evaluated. The results suggested that suitable solutions could significantly improve the removal efficiency of fine particles. Among these, kappa-carrageenan performed best and achieved a removal efficiency of 47.1%. Synergism was detected as two different chemical agglomeration solutions were mixed together: a mixture of kappa-carrageenan and konjac glucomannan attained a removal efficiency of 59.3%, higher than their individual values. The efficiency improved initially and then decreased as the solution K + concentration increased. Also surfactants affected agglomeration: cationic and non-ionic surfactants enlarged the removal efficiency by 9.0% and 3.7%, respectively, whereas anionic surfactants lessened average removal efficiency by 5.6%. Zeta potential influenced the removal efficiency as well: it peaked as the zeta potential was around 0 mV.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 6
·1205
·
IF 3.2
Qingsong Zhang,Huaqiang Sheng,Jinliang Li,Jinhu Li,Hao Zhang
In order to address the issue of wind leakage leading to spontaneous coal combustion in goafs during gob-side entry mining, a KH570 silane coupling agent (SCA)-modified vinyl acetate–ethylene (VAE)/cement-based flexible spraying sealing material was developed. The mechanical properties and wind leakage sealing performance of the material were evaluated using specialized testing equipment. Furthermore, molecular dynamics simulations and microstructural characterization techniques were utilized to assess and model the interface compatibility of the material. The experimental results demonstrate that KH570 significantly enhanced the material’s mechanical properties. Following modification, the material exhibited increases in the maximum tensile strength, compressive strength, and flexural strength by 53%, 38%, and 29%, respectively. KH570 not only promotes the formation of additional calcium silicate hydrate (C-S-H) gel through cement hydration, but also establishes Si-O-Si chemical bonds with cement hydration products and hydrogen bonds with the VAE emulsion. This functions as a “molecular bridge”, significantly enhancing the interface performance of the composite. The interaction between the organic and inorganic phases contributes to the formation of an interpenetrating network structure, imparting excellent compressive, flexural, and tensile deformation resistance to the material. The wind leakage of the spray-modified material was reduced by 2.7 times compared to the unmodified material, significantly improving its sealing performance under mining-induced pressure conditions. This enhancement effectively minimizes spontaneous combustion in mined-out coal areas caused by wind leakage, thereby ensuring safer mining operations.
研究领域:
材料科学
·
分子动力学
·
采矿工程
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2017
·
IF 4.601
Yiquan Guo,Yongchun Zhao,Shaolong Wang,Cheng Jiang,Junying Zhang
Fly ash fine particles emitted from flue gas during coal combustion are the primary atmospheric pollutants in China. The purpose of this study was to investigate the characteristics of the zeta potential of fine particle suspensions. The relationship between the zeta potential and the fine particle removal efficiency was also discussed. Batch experiments were conducted to evaluate the zeta potential of fine particle aqueous solutions under various pH, ion concentration, surfactant, polymer, and chemical agglomeration solution conditions. A chemical agglomeration system was designed to simulate the removal process of the fine particles. The test results indicated that the zeta potential absolute value of the solution decreased initially and then increased as the pH increased. As the pH increased from 4 to 12, the zeta potential decreased from Zp = 9.4 mV to Zp = −45.4 mV. The isoelectric point (IEP) was 4.3. Also at the IEP, the highest fine particle removal efficiency of 25.9% was achieved. The zeta potential increased as the metal cation concentration of the solutions increased. The trivalent cation Al 3+ exhibited the best performance, which increased Zp from −32.1 mV to −11.2 mV and produced the highest fine particle removal efficiency of 9.2%. Polymers significantly impacted the zeta potential. As the concentration of kappa-carrageenan (CAR) increased from 0.01% to 5%, the zeta potential increased from −30.1 mV to 12.6 mV. The highest fine particle removal efficiency of 41.8% was acquired at a concentration of 0.5%, which had the lowest zeta potential absolute value of 3.5 mV. It can be inferred that the increase in the zeta potential induced the growth of the energy barrier, which prevented particle agglomeration. The suspension with a lower zeta potential exhibited a better fine particle removal efficiency.
研究领域:
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2023
·
IF 7.7
Guo-chang Song,Xing-yu Yang,Zhong-wei Li,Qiang Song
Arsenic (As) pollutants are highly toxic and using Ca-based minerals to adsorb As 2 O 3 is effective for emission control. In this study, a fixed-bed experimental system was used to study the adsorption of As 2 O 3 by the mixture of CaO, SiO 2 , and Al 2 O 3 at 1200 °C. The amount of As adsorbed by multiple minerals was higher than that by single minerals, indicating enhanced adsorption of As 2 O 3 under the coupling effects of Ca, Si, and Al. The adsorption amount of As first increased and then decreased with an increase in the CaO:(SiO 2 +Al 2 O 3 ) and SiO 2 :Al 2 O 3 ratios. Adsorbed As was mainly enriched in Ca-Si-Al mineral, including Ca 2 Al 2 SiO 7 . Density Functional Theory calculation was conducted to study the As 2 O 3 adsorption on the Ca 2 Al 2 SiO 7 (0 0 1) surface. The analysis of Mulliken charge and density of states showed that As 2 O 3 molecules formed Al-O, O-As, and Ca-O bonds with the Al, O, and Ca sites. Si and Al in Ca 2 Al 2 SiO 7 enhanced the adsorption ability of Ca sites by promoting electron transfer . Si/Al ratio close to 1:1 is conducive to the formation of Si-O-Al structures, thus further enhancing the adsorption. The results can help optimize coal blending strategies and modify adsorbents to further reduce As emissions during coal combustion .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Yuxuan Yang,Zhaoping Zhong,Jiefei Li,Haoran Du,Qian Li,Xiang Zheng,Renzhi Qi,Shan Zhang,Zhaoying Li
Heavy metals produced by coal combustion tend to bring environmental pollution. The modified additives were prepared by kaolin to capture heavy metals from coal combustion and analyzed by XRD, XRF, FT-IR, SEM and BET. The experimental results showed that the retention rates of heavy metals were ranked as Cr > Zn > Pb > Cd. The best retention of heavy metals was achieved at 1000 °C, while the retention capacity gradually decreased from 1000 to 1300 °C. The trapping effect of heavy metals in dynamic experiment is better than static experiment at 1300 °C. The general ranking of the adsorption capacity of the additives for the four heavy metals was pseudo boehmite-metakaolin (PBK) > aluminum sulfate impregnated metakaolin (AlSK) > metakaolin (MKA) > original kaolin (OKA). The PBK was the best adsorbent with the greatest retention rates of 77.35 %, 74.68 %, 83.35 % and 80.41 % for Pb, Cd, Cr and Zn, respectively. In addition, PBK showed the most significant improvement in the trapping of four heavy metals, with an average improvement of 37.79 % compared to no additives. The geometry models of heavy metal compounds and adsorbents were optimized. The heavy metal oxides were more stable than the chlorides and were more easily adsorbed. There is competitive adsorption between oxides and chlorides of heavy metals. The Al-O-Si-H and Al-O-Si are the best adsorption surfaces for OKA and MKA, respectively. However, CdO and CdCl 2 are hardly adsorbed on the Si-O surface of OKA. The frontline orbitals of four heavy metal oxides/chlorides, θ-Al 2 O 3 and α-Al 2 O 3 have been simulated. Computer simulations show that the mechanism of heavy metal oxide/chloride adsorption on additives is a stronger electron transfer induced interaction between the highest occupied molecular orbital of the adsorbate and the lower unoccupied molecular orbital of the adsorbent, which facilitates the formation of stable chemical bonds.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2016
·
IF 5.393
Hailong Li,Lei Zhu,Jun Wang,Liqing Li,Kaimin Shih
The surface area of zinc sulfide (ZnS) was successfully enlarged using nanostructure particles synthesized by a liquid-phase precipitation method. The ZnS with the highest surface area (named Nano-ZnS) of 196.1 m2·g–1 was then used to remove gas-phase elemental mercury (Hg0) from simulated coal combustion fuel gas at relatively high temperatures (140 to 260 °C). The Nano-ZnS exhibited far greater Hg0 adsorption capacity than the conventional bulk ZnS sorbent due to the abundance of surface sulfur sites, which have a high binding affinity for Hg0. Hg0 was first physically adsorbed on the sorbent surface and then reacted with the adjacent surface sulfur to form the most stable mercury compound, HgS, which was confirmed by X-ray photoelectron spectroscopy analysis and a temperature-programmed desorption test. At the optimal temperature of 180 °C, the equilibrium Hg0 adsorption capacity of the Nano-ZnS (inlet Hg0 concentration of 65.0 μg·m–3) was greater than 497.84 μg·g–1. Compared with several commercial activated carbons used exclusively for gas-phase mercury removal, the Nano-ZnS was superior in both Hg0 adsorption capacity and adsorption rate. With this excellent Hg0 removal performance, noncarbon Nano-ZnS may prove to be an advantageous alternative to activated carbon for Hg0 removal in power plants equipped with particulate matter control devices, while also offering a means of reusing fly ash as a valuable resource, for example as a concrete additive.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2021
·
IF 6.609
Zeyu Xue,Lu Dong,Zhaoping Zhong,Xudong Lai,Yaji Huang
Raw montmorillonite (MMT) was modified by intercalation-exfoliation method to improve the capture capacity of heavy metals (Pb, Zn, Cr and Cd) during coal combustion . Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) Spectroscopy and Brunner-Emmett-Teller (BET) indicated that intercalation agents cetyltrimethylammonium bromide (CTAB) and sodium dodecyl benzene sulfonate (SDBS) could be successfully inserted into the interlayer of MMT during the intercalation step, additionally exfoliation process could peel off the MMT into fine flakes. The co-combustion of coal and MMTs was conducted in a tube furnace from 900 to 1300 °C. Results indicated that with the increase of temperature, the retention ratio of Pb, Zn and Cd gradually decreased, especially higher than 1200 °C with a great capture capacity reduction, whereas for Cr, it rose first and then decreased. The capture performance of modified MMT on Pb, Zn and Cr was obviously improved. However, for Cd, adverse effect was observed, of which the capacity was even worse than that of raw MMT in some cases. According to the mechanism analysis, the intercalation-exfoliation modification of MMT primarily enhances the chemisorption of heavy metals by exposing more active sites, which facilitates the fixation of heavy metals in the form of aluminosilicates .
研究领域:
环境科学
·
能源与燃料
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 46
·69450-69461
·
IF 5.19
Liu Ye,Ma Chenglong,Zhou Jiacheng,Zhu Lin,Cao Limei,Yang Ji
Activated carbon was one of the main adsorptions utilized in elemental mercury (Hg 0 ) removal from coal combustion flue gas. However, the high cost and low physical adsorption efficiency of activated carbon injection (ACI) limited its application. In this study, an ultra-high efficiency (nearly 100%) catalyst sorbent-Se x /Activated carbon (Se x /AC) was synthesized and applied to remove Hg 0 in the simulated flue gas, which exhibited 120 times outstanding adsorption performance versus the conventional activated carbon. The Se x /AC reached 17.98 mg/g Hg 0 adsorption capacity at 160 °C under the pure nitrogen atmosphere. Moreover, it maintained an excellent mercury adsorption tolerance, reaching the efficiency of Hg 0 removal above 85% at the NO and SO 2 conditions in a bench-scale fixed-bed reactor. Characterized by the multiple methods, including BET, XRD, XPS, kinetic and thermodynamic analysis, and the DFT calculation, we demonstrated that the ultrahigh mercury removal performance originated from the activated Se species in Se x /AC. Chemical adsorption plays a dominant role in Hg 0 removal: Selenium anchored on the surface of AC would capture Hg 0 in the flue gas to form an extremely stable substance-HgSe, avoiding subsequent Hg 0 released. Additionally, the oxygen-containing functional groups in AC and the higher BET areas promote the conversion of Hg 0 to HgO. This work provided a novel and highly efficient carbon-based sorbent -Se x /AC to capture the mercury in coal combustion flue gas.
Selenium-modified porous activated carbon and the interface functional group promotes the synergistic effect of physical adsorption and chemical adsorption to promote the adsorption capacity of Hg 0 .
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2018
·
IF 3.789
Zequn Yang,Hailong Li,Shihao Feng,Pu Li,Chen Liao,Xi Liu,Jiexia Zhao,Jianping Yang,Po-Heng Lee,Kaimin Shih
Nanostructured copper sulfide synthesized with the assistance of surfactant with nanoscale particle size and high Brunauer–Emmett–Teller surface area was for the first time applied for the capture of elemental mercury (Hg0) from coal combustion flue gas. The optimal operation temperature of nano-CuS for Hg0 adsorption is 75 °C, which indicates that injection of the sorbent between the wet flue gas desulfurization and the wet electrostatic precipitator systems is feasible. This assures that the sorbent is free of the adverse influence of nitrogen oxides. Oxygen (O2) and sulfur dioxide exerted a slight influence on Hg0 adsorption over the nano-CuS. Water vapor was shown to moderately suppress Hg0 capture efficiency via competitive adsorption. The simulated adsorption capacities of nano-CuS for Hg0 under pure nitrogen (N2), N2 + 4% O2, and simulated flue gas reached 122.40, 112.06, and 89.43 mgHg0/g nano-CuS, respectively. Compared to those of traditional commercial activated carbons and metal sulfides, the simulated adsorption capacities of Hg0 over the nano-CuS are at least an order of magnitude higher. Moreover, with only 5 mg loaded in a fixed-bed reactor, the Hg0 adsorption rate reached 11.93–13.56 μg/g min over nano-CuS. This extremely speedy rate makes nano-CuS promising for a future sorbent injection technique. The anisotropic growth of nano-CuS was confirmed by X-ray diffraction analysis and provided a fundamental aspect for nano-CuS surface reconstruction and polysulfide formation. Further X-ray photoelectron spectroscopy and Hg0 temperature-programmed desorption tests showed that the active polysulfide, S–S dimers, and copper-terminated sites contributed primarily to the extremely high Hg0 adsorption capacity and rate. With these advantages, nano-CuS appears to be a highly promising alternative to traditional sorbents for Hg0 capture from coal combustion flue gas.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
TALANTA
·
2023
·
IF 6.1
Xiao Tian,Lei Zhao
Concentrations of trace elements in coal and coal combustion products are commonly analyzed by inductively coupled plasma-mass spectrometry (ICP-MS) due to large number of elements detected and the relatively the low detection limits of this technique. Like other geological samples, complete dissolution of coal and coal combustion products is also essential for accurate ICP-MS results. In this study, Sr and Ba in coal and coal combustion products (fly and bottom ashes) from two coal-combustion power plants from North China analyzed by XRF and ICP-MS were comparatively studied. The concentrations of Sr and Ba analyzed by ICP-MS, when a mixture of acids (2 ml HF + 5 ml HNO 3 for each 50 mg coal sample and 5 ml HF + 2 ml HNO 3 for each 50 mg ash sample) was used for microwave-assisted digestion, do not fit well with the their relative XRF results. This is most probably due to the formation of the fluorides during microwave digestion, and this assumption is supported by the presence of various fluoride compounds, NaMgAl(F, OH) 6 ·H 2 O, NH 4 MgAlF 6 , AlF 3 , and K 2 SiF 6 , in the residues of all the coal and ash samples in our sequential extraction experiment. Cations of Sr and Ba were probably trapped into the divalent cation sites of the fluorides. Concentrations of Sr and Ba analyzed by ICP-MS using increased HF and HF/HNO 3 ratio (7 ml HF and 2 ml HNO 3 for each 50 mg coal/ash sample) are in better agreement with the XRF results. Our results indicate that excess amount of HF probably has led to the suppression of these elements due to fluoride precipitation. The results indicate that the modified digestion method is capable of achieving complete digestion of coal samples and results in a reliable analysis of Sr and Ba concentrations in coal samples and most fly ashes by ICP-MS. However, the formation of insoluble fluorides is probably not completely suppressed for some bottom ash samples, which can result in underestimation of Sr and Ba concentrations. Nevertheless, XRF analysis can serve as a reliable cross-check method to assist in the evaluation of the accuracy of ICP-MS results.
研究领域:
环境科学
·
分析化学
·
地球化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）