CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2021
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IF 3.171
Xuemei Wu,Minghui Tan,Bing Xu,Shengying Zhao,Qingxiang Ma,Yingluo He,Chunyang Zeng,Guohui Yang,Noritatsu Tsubaki,Yisheng Tan
The effects of crystallite size on the physicochemical properties and surface defects of pure monoclinic ZrO 2 catalysts for isobutene synthesis were studied. We prepared a series of monoclinic ZrO 2 catalysts with different crystallite size by changing calcination temperature and evaluated their catalytic performance for isobutene synthesis from syngas. ZrO 2 with small crystalline size showed higher CO conversion and isobutene selectivity, while samples with large crystalline size preferred to form dimethyl ether (DME) instead of hydrocarbons, much less to isobutene. Oxygen defects (O Defects ) analyzed by X-ray photoelectron spectroscopy (XPS) provided evidence that more O Defects occupied on the surface of ZrO 2 catalysts with smaller crystalline size. Electron paramagnetic resonance (EPR) and ultraviolet–visible diffuse reflectance (UV–vis DRS) confirmed the presence of high concentration of surface defects and Zr 3+ on m -ZrO 2 -5.9 sample, respectively. In situ diffuse reflectance infrared Fourier transform spectroscopy ( in situ DRIFTS) analysis indicated that the adsorption strength of formed formate species on catalyst reduced as the crystalline size decreased. These results suggested that surface defects were responsible for CO activation and further influenced the adsorption strength of surface species, and thus the products distribution changed. This study provides an in-depth insight for active sites regulation of ZrO 2 catalyst in CO hydrogenation reaction.
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高影响因子
JOURNAL OF THE ENERGY INSTITUTE
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2024
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IF 5.6
Yong-hong Niu,Zheng-yang Chi,Shuang Han,Ming Li,Feng-tao Han
Biomass is considered a renewable green coal, and its clean and efficient utilization is of great significance for energy conservation and carbon reduction. One of the most critical aspects of biomass gasification is the selection of an appropriate catalyst. In this study, we synthesized a catalyst with 10 % Pr 1-x Ce x CoO 3 supported on dolomite using the sol-gel method. We conducted graded internal circulation gasification experiments to produce hydrogen-rich syngas. The effects of element substitution in PrCoO 3 , temperature, catalyst composition, and steam injection rate on the products were investigated. The optimal gasification conditions were determined through response surface regression analysis. The data indicate that this catalyst can improve gasification efficiency, with Pr 0.4 Ce 0.6 CoO 3 /Dol showing the best catalytic performance. It effectively reduces the required gasification temperature and steam amount, decreases CO 2 production, and increases CO and H 2 yields. The catalyst accelerates the cleavage and ring-opening reactions of hydrocarbons, leading to terminal chain hydroxylation, followed by the dehydration-condensation of methyl groups into ethers. As the temperature rises, the rate of carboxyl group removal gradually exceeds the rate of carboxyl group formation via the oxidation of hydroxyl and ether chains, resulting in an initial increase and then a decrease in the number of carboxyl groups. Under optimal gasification conditions, CO 2 production is reduced by one-fourth compared to using a dolomite catalyst.
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ENERGY CONVERSION AND MANAGEMENT
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2024
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IF 9.9
Mi Yan,Chuanhai Luo,Dicka Ar Rahim,Yu Liu,Haocheng Wang,Jinghao Ye,Yansong Sun,Ekkachai Kanchanatip
Hydrothermal carbonization has become increasingly prevalent in the pretreatment of food waste, leading to the generation of substantial volumes of liquid effluent. This hydrothermal liquid effluent from food waste (HLF) contains high content of organic compounds, making it challenging to treat using conventional methods. In this regard, the HLF was considered a potential source for energy production via supercritical water gasification (SCWG). This study aimed to develop effective bimetallic catalysts based on Ni/Al 2 O 3 with four different promoters (Cu, Co, La, and Ce), and investigated their performance in the catalytic SCWG for the treatment of HLF and hydrogen production. Among the tested promoters, the Ce-Ni catalyst was considered the most suitable in terms of its highest H 2 yield and H 2 selectivity. The optimal Ce content was found to be 5 wt%, with a catalyst dosage of 5 % by weight of HLF. These conditions resulted in the highest H 2 selectivity of 1.61 and a relatively high H 2 yield of 749.60 mmol/L under SCWG operating conditions of 480 °C and 30 min. Excessive catalyst dosages increased total syngas yield but reduced H 2 selectivity. The stability test demonstrated that the Ce promoter contributed to enhancing the catalyst resistance to deactivation by coke deposition. The hydrogen production of 5Ce-Ni decreased by 13.8 % after three reuses, whereas a larger decrease of 26.0 % was observed with Ni/Al 2 O 3 . These findings indicate that Ce-Ni catalyst show promise for enhancing H 2 -rich syngas production in the SCWG of hydrothermal liquid effluent from food waste.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2021
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IF 9.642
Juan Luo,Rui Ma,Jiaman Sun,Guojin Gong,Shichang Sun,Haowen Li
This study firstly coupled advanced continuous microwave pyrolysis with CO 2 reforming technology to recover syngas from cow manure and CO 2 . The contribution of CO 2 to syngas, pyrolysis mechanism, and energy balance characteristics were analyzed thoroughly. The results showed that continuous microwave pyrolysis coupled with CO 2 reforming technology has superiorities over other pyrolysis methods in bio-gas generation. The bio-gas yield, syngas content, and heating value of syngas reached the maximum value of 71.02 wt%, 85.70 vol%, and 10.87 MJ/Nm 3 , respectively. CO 2 strengthened pyrolysis and reacted with pyrolysis products to produce high-quality syngas and reduce H 2 S. Due to the limited substances that can react with CO 2 and excessive energy consumption with increasing CO 2 concentration, the utilization efficiencies of CO 2 and energy decreased from 36.31% and 27.27% to 31.16% and 24.24%, respectively. This work provides basic theory and technical support for advanced technology to recover high-quality syngas from biomass with low energy consumption.
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高影响因子
ACS Applied Energy Materials
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2022
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IF 6.959
Jiale Wang,Qian Xiang,Wencong Zhang,Fenglei Shi,Fan Li,Peng Tao,Chengyi Song,Wen Shang,Tao Deng,Jianbo Wu
Electrochemical CO2 reduction (ECR) into syngas is a promising method to reduce CO2 in the atmosphere. However, balancing the activity of ECR and hydrogen evolution reaction (HER) and controlling the stable CO/H2 ratios in a large potential range for the industrial desired syngas are still challenging. Herein, a low-cost Ni-doped ZnO nanosheet array on a zinc foil is synthesized via a convenient hydrothermal method to produce a controllable ratio of CO/H2 into syngas. Because of the lower impedance and larger electrochemical area, Ni-doped ZnO has a more significant current density. Furthermore, by adjusting the Ni doping content in the ZnO nanosheet, the activity of ECR and HER could be controlled, and the ratio of CO/H2 can be tuned from 0.1 to 4.5 over a wide potential range (−1.2 to −1.8 V vs reversible hydrogen electrode, RHE), surpassing most of the reported work. Such a wide range and stable ratio of CO/H2 in a broad potential range makes it possible to convert CO2 into feedstock for many essential chemical products.
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高影响因子
APPLIED ENERGY
·
2024
·
IF 10.1
Xianqing Zhu,Mian Xu,Shiyang Hu,Ao Xia,Yun Huang,Zhang Luo,Xiao Xue,Yao Zhou,Xun Zhu,Qiang Liao
Introducing waste plastics with high hydrogen contents (such as polyethylene) into the biomass gasification process is an effective way to upgrade the syngas . Despite their good catalytic abilities, some of the transition metals commonly applied for the co-gasification of biomass and plastic wastes are of high cost and have poor availability, which requires developing affordable transition metal-based catalysts with desirable catalytic performances for producing H 2 -rich syngas . Spent lithium-ion batteries , which have a huge annual output and pose a great threat to the environment, contain a high potential to prepare efficient catalysts for biomass and plastic co-gasification due to the richness of active transition metals (e.g., Ni, Co and Mn). Therefore, in this study, a novel Ni/Co/Mn-loaded mesoporous Al 2 O 3 catalyst was developed from the thermally decomposed spent LiNi x Co y Mn 1−x−y O 2 batteries (spent LIBs) for pinewood sawdust and polyethylene co-gasification as an effective means to achieve the zero-waste strategy. The results showed that Ni, Co and Mn could be non-selectively recycled from spent LIBs and uniformly loaded on γ -Al 2 O 3 support, and the support's mesopores were well-retained (average pore diameters around 11 nm). The highest H 2 productivity of the co-gasification could reach 17.16 mmol g −1 with a concentration of 36 vol% over the LIB-modified Al 2 O 3 . The modification by spent LIBs would enhance the catalyst's relative concentrations of acid-base sites in high-temperature regions, leading to the significant promotion of H 2 productivity from 600 to 800 °C (151.3%). Nickel and manganese in the LIBs were primarily responsible for the catalysis since their nanosized particles could endow the catalyst with accessible and reducible metallic sites for volatile reforming. The synergy among the Ni, Co and Mn could evidently intensify the oxygen vacancies of the LIB-modified Al 2 O 3 to promote the oxygen transfer reactions from steam to dissociative species for H 2 production. This study provided a novel and promising technology for synergistic valorization of spent lithium-ion batteries, biomass residues and plastic wastes to produce value-added H 2 -rich syngas.
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高影响因子
FUEL
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2024
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IF 6.7
Chenxuanzi Wang,Mingxuan Zhong,Yongcheng Cai,Zewei Zhang,Bo Xiao,Tingting Xu,Xun Wang
The chemical looping reforming coupled with CO 2 splitting (CLR-CS) offers a promising solution for syngas production and simultaneous decomposition of CO 2 . In this study, the Sr-Fe based oxygen carriers (OCs) were evaluated in CLR-CS using ethanol as fuel. The presence of Sr significantly improved the oxidation performance of iron oxides. The Sr element in fresh Sr-Fe based OCs mainly formed two crystal phases, including SrFe 12 O 19 and Sr 4 Fe 6 O 13 . Increasing the amount of Sr element made it easier to form Sr 4 Fe 6 O 13 crystal phase. The Sr 4 Fe 6 O 13 was favorable for syngas production, due to the higher surface oxygen vacancy formation energy with a range of 3.13–3.37 eV. However, the lower oxygen transfer capacity (OTC) of Sr 4 Fe 6 O 13 resulted in a lower CO yield in the of stage of CO 2 decomposition. Compared with Sr 4 Fe 6 O 13 , SrFe 12 O 19 exhibited the higher OTC and the higher reactivity of lattice oxygen, which was preferable to produce more CO 2 in the stage of ethanol reforming in fuel reactor. During the cycle tests, the crystalline phase of SrFe 12 O 19 didn’t regenerate under the CO 2 atmosphere but transformed into Sr 4 Fe 6 O 13 . It was attributed to the lower energy barrier of CO 2 oxidation on the oxygen defect surface of Sr 4 Fe 6 O 13 . The phase transformation of SrFe 12 O 19 accompanied the formation of Fe 3 O 4 . The excessive Fe 3 O 4 had poor stability and inactivated easily due to sintering and agglomeration in Sr1Fe4 and Sr1Fe6 samples. The Sr1Fe2, namely the molar ratio of SrO to Fe 2 O 3 of 1:2, exhibited the better performance for syngas (0.291 Nm 3 /kg OC) and CO (0.141 Nm 3 /kg OC) coproduction at 800 °C. Additionally, the Sr1Fe2 presented an excellent cyclic stability in 30 cycles due to the suitable proportion of Sr 4 Fe 6 O 13 and iron oxides formed, which maintained a high syngas yield and avoided sintering of iron oxides. Overall, the Sr1Fe2 is a promising OC candidate in CLR-CS process.
研究领域:
能源科学
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材料科学
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高影响因子
ENERGY
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2024
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IF 9
Tao Tan,Yushu Chen,Yongyue Wang,Zuhao Li,Zhige Zhang,Jun Xie,Yong Chen
The use of green biogas as a raw material for producing methanol-friendly syngas (H 2 /CO ≈ 2) for one-step methanol synthesis has gained significant attention. However, developing efficient catalysts with high activity and stability remains challenging, as they often face issues with stability and carbon deposition. This study presents a Ni/CeO 2 /HT catalyst designed for high activity and long-term stability by leveraging the Ce redox cycle and strong interactions between Ni-CeO 2 and hydrotalcite (HT). The catalyst benefits from abundant oxygen vacancies generated by the Ce 3+ - Ce 4+ pathway, enhancing its ability to activate CO 2 and H 2 O and providing excellent coke resistance. Comprehensive analyses of CO 2 /H 2 O adsorption and carbon elimination mechanisms were conducted using techniques such as in situ H 2 -TPR, CO 2 /H 2 O-TPSR, in situ CH 4 -TPSR, CO 2 /H 2 O-TPO, and FTIR. The Ni/CeO 2 /HT catalyst outperformed others in CO 2 /H 2 O adsorption and CH 4 activation capacity, promoting the generation of active oxygen species and effectively removing coke precursors, thereby improving resistance to Ni sintering and carbon deposition. At 750 °C and a weight hourly space velocity (WHSV) of 32,400 mLg Cat −1 h −1 , it achieved CH 4 and CO 2 conversions of 93 % and 66 %, respectively, with long-term stability exceeding 200 h.
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高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2024
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IF 8.1
Heyu Li,Zhe Sun,Yan Cao
Gypsum (GP) by-products are a group of widely sourced sulfur-containing solid wastes and their recycling utilizations are of great significance. This work proposed a new cyclic GP utilization process, achieving both the sulfur recovery and simultaneous value-added syngas byproduct under the restriction of the CO 2 capture. This innovative process integrates the carbon-fueled and calcium-based chemical-looping technology to generate concentrated SO 2 , followed by the recovery of the sulfur to be a concentrating sulfuric acid via the iodine–sulfur thermochemical cycle and finally the CO 2 capture to produce CaCO 3 /(NH 4 ) 2 SO 4 by the use of the in-situ generating calcium adsorbent via the NH 3 -Merseburg process. Its feasibility was thermodynamically and experimentally validated. It’s found that the elevated temperature and the weak reducing atmosphere were conducive to a nearly 100% thermally-decomposed of GP (mainly CaSO 4 ) toward a mixture of CaS and CaO (a ratio in 4:6) and the maximum per pass carbon conversion over 80% using carbon fuels (coal), and the carbon residues can be recovered back to carbon fuel stream. The recovery of I 2 can be achieved through the electrochemical electrolysis method and then recycled. The optimization of heat exchange network results in energy consumption reduction by 79.6% and 75.2% for hot and cold utilities, respectively.
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高影响因子
Catalysis Science & Technology
·
2019
·Vol. 9
·期 15
·3933-3946
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IF 5.726
Ting Wang,Yuebing Xu,Chengming Shi,Feng Jiang,Bing Liu,Xiaohao Liu
Direct conversion of syngas (CO/H2) into aromatics over tandem catalysts via the Fischer–Tropsch synthesis (FTS) route has attracted much attention because of its high one-pass conversion and milder reaction conditions. However, the complicated FTS product composition leads to more difficult mechanistic elucidation of aromatics formation compared to the methanol route. Herein, a series of strategies, such as covering external surface acid sites of HZSM-5 with a layer of inert SiO2, layered loading of an FeMn FTS catalyst and HZSM-5 zeolite in one reactor and two tandem reactors, and model reactions with ethylene and propylene over zeolite in a simulated FTS reaction environment, were applied to unveil the reaction mechanism and related factors affecting aromatic selectivity. It was found that different from the methanol route, the tandem FeMn–HZSM-5 catalyst produced aromatics mainly from the conversion of C5+ FT intermediates rather than light olefins (C2=–C4=). SiO2 coating could remarkably enhance the para-xylene (PX) selectivity due to hindering of its isomerization to major meta- and minor ortho-xylene (MX and OX) on the external surface acid sites of HZSM-5 by releasing the space confinement. The layered loading experiments in one reactor demonstrated that a farther distance from the FTS catalyst to zeolite largely increased the selectivity to BTX (benzene, toluene and xylene) in total aromatics from 48.3% to 68.9% on a carbon molar basis by suppressing the alkylation reaction of benzene and toluene with ethylene due to an obviously lower local ethylene concentration on HZSM-5. FeMn and HZSM-5 with layered loading in two tandem reactors confirmed that light olefins (C2=–C4=) were mainly hydrogenated and isomerized into paraffins. The model reactions with ethylene and propylene in a simulated local FTS reaction environment revealed that the presence of H2O and CO2in situ produced from the FTS reaction played a crucial role in promoting the aromatics formation at obviously lower reaction temperature which resulted from the enhancing acid strength and the driving H transfer to facilitate the cyclization and dehydrogenation reaction. This study provides a clear perspective for the aromatics formation mechanism and the tuning of the aromatic selectivity.
研究领域:
化学工程
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催化科学
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2014
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IF 2.93
Haijun Guo,Fen Peng,Hairong Zhang,Lian Xiong,Shanggui Li,Can Wang,Bo Wang,Xinde Chen,Yong Chen
High efficient production of lower alcohols (C 1 –C 5 mixed alcohols) from hydrogen rich bio-oil derived syngas was achieved in this work. A non-catalytic partial oxidation (NPOX) gasification technology was successfully applied in the production and conditioning of bio-oil derived syngas using bio-oil (BO) and emulsifying waste engine oil (EWEO) as feedstock . The effects of water addition and feedstock composition on the gasification performances were investigated. When the BO 20 and EWEO 30 was mixed with mass ratio of 1: 0.33, the maximum hydrogen yield of 93.7% with carbon conversion of 96.7% was obtained, and the hydrogen rich bio-oil derived syngas was effectively produced. Furthermore, a two-stage bed reactor was applied in the downstream process of lower alcohols synthesis from hydrogen rich bio-oil derived syngas (H 2 /CO/CO 2 /CH 4 /N 2 = 52.2/19.5/3.0/9.4/15.9, v/v). The highest carbon conversion of 42.5% and the maximum alcohol yield of 0.18 kg/kg cat h with selectivity of 53.8 wt% were obtained over the Cu/ZnO/Al 2 O 3 (2.5)//Cu 25 Fe 22 Co 3 K 3 /SiO 2 (2.5) catalyst combination system. The mechanism and evaluation for lower alcohols synthesis from model bio-oil derived syngas and model mixture gas were also discussed. The integrative process of hydrogen rich bio-oil derived syngas production and downstream lower alcohols synthesis, potentially providing a promising route for the conversion of organic wastes into high performance fuels and high value-added chemicals.
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