FUEL
·
2025
·
IF 7.5
Liuling Yin,Hua Yang,Xi Cao,Changsheng Bu
Oxygen carrier-aided combustion (OCAC) in biomass combustion has the potential to improve fuel conversion efficiency and reduce CO 2 emissions. However, the key mechanisms of oxygen carriers (OCs) in OCAC remain unclear, and the influence of biomass ash on combustion characteristics hinders the industrial application of this technology. In this study, a bench-scale bubbling fluidized bed experimental apparatus is employed, utilizing three types of biomass (sawdust, rice husk, and wheat straw) as fuels, and AR-Fe 2 O 3 , hematite, and steel slag as OCs. The focus is on assessing the influence of OCs on the combustion characteristics of biomass, as well as exploring the effects of ash on these characteristics, all within the atmosphere of 10% O 2 and 90% CO 2 maintained at a temperature of 850℃.The results indicate that AR-Fe 2 O 3 , with high lattice oxygen content and substantial oxygen storage capacity, does not engage in competitive gaseous oxygen (O 2 (g)) uptake with biomass char but instead facilitates efficient oxygen transfer, accelerates the carbon reaction rate, shortens the burnout times, and elevates the generation of CO. Conversely, hematite and steel slag reduce CO generation through low content lattice oxygen reactions with CO, then the oxygen vacancies compete with biomass char for O 2 (g), leading to slower combustion rates and longer burnout times. Although ash in raw biomass char maybe hinder combustion, the structural modifications induced by demineralization are dominant under short reaction times, significantly enhancing combustion performance. The findings providing a guidance for OC selection and biomass pretreatment strategies, supporting the optimization of OCAC for industrial biomass energy applications.
✓ 已验证
产品关联
DOI
高影响因子
Applications in Energy and Combustion Science
·
2023
·
IF 0
Cao Kuang,Mumin Rao,Xiangbo Zou,Jinchen Ma,Ji Ye,Shiwei Qin,Gongda Chen,Shuzhong Wang,Jun Zhao
This effort is to investigate three different Cu-based oxygen carriers (OCs) with polyvinyl chloride (PVC) and coal in chemical-looping combustion (CLC). The combustion process and synergetic analysis of PVC with coal were evaluated. There were four stages in the reaction of OCs with PVC, which HCl released from PVC could react with OCs at about 200–400 °C. CuO and CuO modified by limestone showed better immobilization of chlorine while CuO modified by iron ore and chrysolite inhibited the reaction of HCl with CuO. PVC char combustion temperature started at about 500 °C which were lower than that of coal char. The combustion efficiency of PVC CLC was all above 92%, except using Cu-Fe as OC which was about 88%. The presence of ZD in PVC showed positive effect on every stage. The addition of coal inhibited the reaction of HCl with CuO. The presence of PVC in ZD reduced the temperature of coal char and the addition of ZD in PVC increased the reaction rate. The synergistic effect was obvious between the PVC and coal blends which is beneficial for the complete combustion in solid fuel CLC
研究领域:
能源与燃料
·
环境科学
✓ 已验证
DOI
Catalysts
·
2015
·Vol. 6
·期 1
·6
·
IF 2
Jie Fu,Dong Sheng,Xiuyang Lu
Four types of nickel catalysts supported on aluminum oxide (Ni/Al2O3) with different nickel loadings were synthesized using the co-precipitation method and were used for the hydrogenation of levulinic acid (LA) to prepare γ-valerolactone (GVL). The synthesized Ni/Al2O3catalysts exhibited excellent catalytic activity in dioxane, and the activity of the catalysts was excellent even after being used four times in dioxane. The catalytic activity in dioxane as a solvent was found to be superior to the activity in water. Nitrogen physisorption, X-ray diffraction, and transmission electron microscopy were employed to characterize the fresh and used catalysts. The effects of the nickel loading, temperature, hydrogen pressure, and substrate/catalyst ratio on the catalytic activity were investigated.Keywords:nickel supported on aluminum oxide;γ-valerolactone;levulinic acid;hydrogenation;dioxane
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
Chemosensors
·
2023
·Vol. 11
·期 5
·289
·
IF 4.2
Ji Zhang,Fangfang Zhang,Xu Li,Qingji Wang
With increasingly serious environmental problems caused by the improvement in people’s living standards, the number of cars has increased sharply in recent years, which directly leads to the continuous increase in the concentration of NO2in the air. NO2is a common toxic and irritant gas, which is harmful to both the human body and the environment. Therefore, this research focuses on NO2detection and is committed to developing high-performance, low detection limit NO2sensors. In this study, flower-like Au-loaded In2O3was successfully fabricated using the hydrothermal method and the wet impregnation method. The morphological features and chemical compositions of the as-prepared samples were characterized using SEM, TEM, XRD and XPS. A variety of sensors were fabricated and the gas-sensing properties of sensors were investigated. The results indicate that the sensor based on 0.5 mol% Au/In2O3shows a response value of 1624 to 1 ppm NO2at 100 °C, which is 14 times that based on pure In2O3. Meanwhile, the detection limit of the sensor based on 0.5 mol% Au/In2O3for NO2is 10 ppb, and the response value is 10.4. In addition, the sensor based on 0.5 mol% Au/In2O3also has high selectivity to NO2among CO, CO2, H2, CH4, NH3, SO2and H2S. Finally, the sensitization mechanism of Au/In2O3was discussed, and the reasons for improving the performance of the sensor were analyzed. The above results and analysis demonstrate that the gas-sensing attributes of the sensor based on 0.5 mol% Au/In2O3to NO2improved remarkably; at the same time, it has been proved that the composite material has extensive potential in practical applications.Keywords:NO2sensor;flower-like;Au-loaded In2O3;low detection limit;high selectivity
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2023
·
IF 7.5
Heyu Li,Zhe Sun,Shaochen Shang,Yan Cao
The development of cost-effective and reactive oxygen carriers and the fast and complete conversion of solid fuels are two critical issues in the solid fuel chemical looping technology. Red mud, a solid waste from the alumina industry, was found to be an economic oxygen carrier candidate simultaneously realizing the use of solid wastes and the CO 2 abatement after comparing with other two different iron-based materials (pure Fe 2 O 3 and hematite). This study validated red mud as an excellent oxygen carrier to achieve the almost complete conversion of char in solid fuels (SFs) (99.4%) and meanwhile the hydrogen production with high-purity (97% H 2 purity) and higher H 2 yield (around 500 mL/g), in the optimized pyrolysis procedure of solid fuels with proper gasification agent and rationalized reaction temperatures (1000 °C) and residence time (10mins). Characterizations of red mud using SEM-EDS and XRD revealed that the unique microscopic crystalline structures of both Fe 2 O 3 and Ca 2 Al 2 SiO 7 particles nested on Na 4 Al 2 Si 2 O 9 molten substrate, implying that the existence of Na-containing component of the red mud OC likely accounts for its higher reactivity and stability in multiple redox cycles.
研究领域:
能源科学
·
材料科学
·
环境工程
✓ 已验证
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Zhen Huang,Zhengbing Deng,Yuheng Feng,Tianju Chen,Dezhen Chen,Anqing Zheng,Guoqiang Wei,Fang He,Zengli Zhao,Jinhu Wu,Haibin Li
As a novel biomass gasification technology, chemical looping gasification (CLG) could in situ catalytically crack biomass tar by oxygen carrier (OC). This study compares the reactivity of different OCs (Al2O3, Fe2O3, NiO, NiO+Fe2O3, and NiFe2O4) to crack a biomass tar model compound (toluene) and preliminarily explores the reaction mechanisms of toluene cracked by NiFe2O4 OC. Among five OCs, NiFe2O4 with a homogeneous Fe/Ni dispersibility shows the best reactivity for toluene cracking with a toluene conversion and H2 yield of 96.83% and 0.91 L/g, respectively. Additionally, on the basis of the dispersibility of active sites on the OC sample surface, the reactivity of the other four OCs to crack toluene shows the sequence NiO+Fe2O3 > Fe2O3 > NiO ≫ Al2O3. A large amount of carbon deposition, including amorphous carbon and graphitized carbon, is generated during toluene catalytic cracking, while the addition of steam significantly eliminates the carbon deposition. The NiFe2O4 OC shows a dual-function of in situ oxidation–catalysis during toluene cracking. A mechanism of four steps is proposed for the toluene cracking on OCs: (I) toluene cracking at high temperature, (II) reduction of OC, (III) generation of amorphous carbon deposition and (III′) formation of graphitized carbon, and (IV) elimination of carbon deposition.
研究领域:
能源科学
·
催化化学
✓ 已验证
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2021
·
IF 7.033
Zhong Ma,Guofu Liu,Yonggang Lu,Junfeng Wang,Hui Zhang
In chemical looping combustion , iron-based oxygen carriers often experienced serious phase segregation , which reduced the cyclic stability of the oxygen carriers. In this work, Fe 2 O 3 /Al 2 O 3 (FA) was doped with different metals (Sr, La and Ce) to improve the redox performance during cyclic reactions. The mechanism of dopants on FA was explored by experimental research and characterization analysis. The promotion effect of different dopants on the redox performance of FA followed the sequence: Sr > La > Ce. It was shown that the deactivation of Ce-FA and La-FA was obvious in 20 cycles. The results of 100 successive cycles indicated that the surface structure of Sr-FA remained stable and no sintering was observed. The Sr-FA achieved stable oxygen carrying capacity (4%) in 100 redox cycles. The characterization results indicated that the addition of Sr could effectively increase the concentration of oxygen vacancies , thus inhibiting the phase segregation of FA. The enrichment degree of surface Fe of FA, Sr-FA, La-FA and Ce-FA were 135.7%, 43.47%, 128.0% and 140.0%, respectively. The results of this study provide guidance for the preparation of iron-based oxygen carriers with high redox performance.
研究领域:
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Zhong Ma,Guofu Liu,Yonggang Lu,Hui Zhang
Iron-based oxygen carriers often underwent severe phase segregation in the process of chemical looping, resulting in the reduction of the cyclic performance of oxygen carriers. The phase segregation characteristics of Fe 2 O 3 /Al 2 O 3 calcined at different temperature (900 °C, 1100 °C, 1300 °C) were investigated in this study. The obtained samples were recorded as 900-FeAl, 1100-FeAl and 1300-FeAl, respectively. XPS results showed that the surface oxygen vacancies of Fe 2 O 3 /Al 2 O 3 increased with the increase of calcination temperature. In the redox cycles, the deactivation rate of the three samples were 5.57% (900-FeAl), 6.99% (1100-FeAl) and 31.69% (1300-FeAl), respectively. After 20 cycles, the 1300-FeAl presented serious surface sintering and the largest enrichment degree of surface Fe (137.05%). It can be inferred that the severe enrichment of surface Fe leads to the serious sintering, which aggravates the deactivation of the 1300-FeAl in cyclic reactions. The low calcination temperature (900 °C, 1100 °C) makes the Fe 2 O 3 /Al 2 O 3 exhibit rich pore structure, which generates space barrier for the outward migration of Fe cation and inhibits the phase segregation of Fe 2 O 3 /Al 2 O 3 . The results of this study are of great significance to understand the phase segregation of iron-based oxygen carriers, and provide guiding value for the synthesis of high-performance iron-based oxygen carriers.
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yifan Zhao,Kejun Qin,Yongcheng Feng,Dunyu Liu,Jinchen Ma,Xu Wu,Qinjue Li,Chuangye Ma,Wensong Pang,Lei Zhang
Iron-based oxygen carriers as one of the most commonly used oxygen carriers in chemical looping combustion, shows poor cycling stability. In this work, spinel-structured, Fe 2 O 3 @MgO core–shell structure, and Fe 2 O 3 /CuO@MgO core–shell structure oxygen carriers were prepared using compression molding . The effects of deep reduction and oxidative regeneration processes on the cyclic stability of oxygen carriers with different structures were investigated using thermal gravimetric analyzer. The mechanisms for the changes in the cyclic stability were explored through a series of characterization analyses. The results showed that the reduction process of spinel oxygen carriers generated Fe-Mg solid solution, which was unfavorable to deep reduction, and phase separation occurred during 5 cycles. Due to the migration of Fe 3+ ions to the surface, surface was seriously sintered, deteriorating the cyclic stability of spinel oxygen carriers. For Fe 2 O 3 @MgO oxygen carrier, the deep reduction can be realized, but the interdiffusion phenomenon of Fe 2+ and Mg 2+ occurred after 5 reductions, and the generation of (MgO) x (FeO) 1−x solid solution impeded the deep reduction. The addition of CuO in the core of oxygen carriers to form Fe 2 O 3 /CuO@MgO could inhibit the interdiffusion of Fe 2+ and Mg 2+ , and maintained the oxygen carrying capacity up to more than 95 % in 10 cycles. Meanwhile, CuO synergized with Fe 2 O 3 to enhance the reduction and oxidation reactivity of the oxygen carrier. On this basis, the ion diffusion mechanism during the deep reduction and oxidation of iron-based oxygen carriers with different structures was proposed. This study provides guidance for the modification of iron-based oxygen carriers with superior cycling stability.
研究领域:
能源科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
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
·
材料科学
✓ 已验证
DOI
高影响因子
FUEL
·
2023
·
IF 7.4
Xinyi Chen,Guangsheng Zou,Yanliang Yuan,Zuwei Xu,Haibo Zhao
The current study investigates a nano-Fe/Ce oxygen carriers (OCs) doped with Ni synthesized by flame spray pyrolysis (FSP) method for the chemical looping dry reforming of methane (CL-DRM). The thermodynamic analysis and reaction simulation of the CL-DRM process with iron-based oxygen carriers are first carried out. The result shows that when reacting with CH 4 , Fe 2 O 3 is reduced to Fe 3 O 4 at first, accompanied by generation of H 2 O and CO 2 , and then to Fe with H 2 and CO production. Fe can be oxidized to Fe 3 O 4 and FeO by CO 2 . Subsequently, based on the reaction patterns obtained from the aforementioned analysis, CL-DRM experiment using Ni-doped Fe/Ce oxygen carriers is conducted in a fixed-bed reactor, and the effects of different Ni doping and reaction conditions on the performance of the oxygen carriers are investigated. The OC with a Ni/Fe molar ratio of 2/98 (2NiFe) achieves over 30% CH 4 conversion and 90% CO selectivity in the partial oxidation step and stable cyclic performance. The FSP process facilitates high dispersion of Ni and formation of NiCe and NiFe alloys, which are stable active sites. Moreover, the transformation of Fe oxides and CeO 2 into CeFeO 3 on the surface of the OC has enhanced lattice oxygen availability and further improved cyclic stability.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
VACUUM
·
2024
·
IF 3.8
Hailin Zheng,Min Zheng,Xianxing Huang,Mingjie Liang,Kang Li
Chemical-looping combustion (CLC) technology is considered a promising combustion method with inherent CO 2 capture. In this study, the sol-gel method and combustion synthesis were employed to produce precursor materials (P) of CuO-based oxygen carriers (OCs). The effects of vacuum drying conditions on both NO x emissions from precursor combustion and oxygen carrier cycle reaction characteristics were investigated. Vacuum-dried precursors emitted less NO x during the precursor calcination process. At a heating rate of 1 °C/min, the vacuum-dried precursors exhibited an average reduction of 24.13 % in NO x emissions compared with those prepared through atmospheric pressure drying. An increased amount of Cu 2 (OH) 3 NO 3 in the precursor results in greater heat release during the self-propagating high-temperature combustion synthesis used to synthesize the oxygen carrier. Furthermore, the complete combustion of the nitrogen-containing precursor leads to a reduction in the emission of NO x . CuO-based OCs exhibited stable redox reactions over 10 cycles. Vacuum drying enhanced CH 4 conversion and CO 2 yield of OC1 by 14.04 % and 13.21 %, respectively, compared to atmospheric pressure drying. The results indicate that the CuO-based OCs obtained through vacuum-dried significantly enhance redox properties. This study shows that vacuum-dried reduces NO x emissions from nitrogen precursors and enhances the cyclic efficiency of OCs from precursor combustion.
研究领域:
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）