FUEL
·
2022
·
IF 8.035
Junhao Lin,Jiaman Sun,Yi Chen,Juan Luo,Chongwei Cui,Shichang Sun
To directionally convert sludge into the high-quality syngas, the effects of various parameters on the biogas produced by the sludge microwave pyrolysis are explored, and the syngas generation mechanism under the synergistic effect of parameters is revealed. The results showed that the pyrolysis final temperature, reaction time, and the amount of the microwave absorber were the key factors that affected the biogas yield. A response surface analysis was used to explore the synergistic effect of each key parameter on the yield and the lower heating vale (LHV) of syngas. The pyrolysis temperature was the key to driving syngas generation. Properly prolonging the reaction time decreased the formation of tar by-products and increased the syngas yield. The addition of a microwave absorber increased the heating rate by enhancing the conversion efficiency of microwave energy, and this contributed to accelerating the dehydrogenation and the Boudouard reactions to promote the generation of H 2 and CO. Under high temperature conditions (900 °C), a higher syngas yield (10.25–34.31 mol/kg DS ) and LHV (4.85–14.53 MJ/kg DS ) were obtained in a shorter period time by synergistically optimizing the amount of microwave absorbers (8–10 g) and the reaction time (28–40 min). As the pyrolysis temperature increased, the H 2 content gradually rose to the peak, while the content of CO continued to increase. By analyzing the evolution of the specific pyrolysis products, the secondary pyrolysis of bio-oil at high temperatures and the Boudouard reaction were found to be the primary pathways that promoted syngas generation. This research provides strategic guidance for producing high-quality syngas using the microwave pyrolysis of waste biomass, thereby minimizing the exploration cost of basic experiments and providing directional control of the syngas quality.
研究领域:
环境科学
·
能源工程
✓ 已验证
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2017
·
IF 5.651
Yu Hong,Wanru Chen,Xiang Luo,Chengheng Pang,Edward Lester,Tao Wu
In this study, three different marine biomasses, i.e., microalgae-spirulina, chlorella and macroalgae-porphyra, were pyrolyzed in a laboratory-scale multimode-microwave cavity at 400, 550 and 700 °C. Ovalbumin and cellulose were also chosen as model compounds to simulate algae. The influence of heating rate on pyrolysis and the βi curves of different samples under different temperatures were studied in detail. The porphyra was found to be the most reactive and produced the largest gaseous fraction (87.1 wt%) amongst the three algae, which comprised of 73.3 vol% of syngas. It was found that nitrogenated compounds in bio-oil were derived from protein in algae while carbohydrate led to the formation of PAHs. For the production of bio-oil, protein-rich microalgae is favorable compared with porphyra due to their lower amount of PAHs, while porphyra is more suitable for the production of H 2 + CO rich gas product, which is comparable with that of conventional gasification processes.
研究领域:
能源生物学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Processes
·
2024
·Vol. 12
·期 11
·2505
·
IF 2.8
Bo Zhang,Lei Wu,Fei Li,Wuwan Xiong,Peiyu Yao,Yang Zhang,Xiang Li
The production of waste textiles has increased rapidly in the past two decades along with the rapid development of the economy, the majority of which has been either landfilled or incinerated, resulting in energy loss and environmental pollution. Microwave pyrolysis, which can transform heterogeneous and complex waste feedstocks into value-added products, is considered one of the most competitive technologies for processing waste textiles. However, achieving selective product formation during the microwave pyrolysis of waste textiles remains a significant challenge. Herein, sodium acetate, potassium acetate, and nickel acetate were introduced into waste textiles through an impregnation method as raw materials to improve the pyrolysis efficiency. The optimized process parameters indicated that nickel acetate had the most favorable promotional effect of the three acetates. Notably, the waste textiles containing 1.0% Ni exhibited the highest gas production rate, with the hydrogen-containing combustible gas reaching 81.1% and 61.0%, respectively. Using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy to characterize the waste textiles before and after pyrolysis, it was found that nickel acetate was converted into metallic nickel (Ni0) during microwave pyrolysis. This active site significantly enhanced the pyrolysis process, and as the gas yield increased, the disorder of the resulting pyrolytic carbon also rose. The proposed Ni0-enhanced microwave pyrolysis mediated by nickel acetate offers a novel method for the efficient disposal and simultaneous resource recovery of waste textiles.
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
ENERGY CONVERSION AND MANAGEMENT
·
2022
·
IF 11.533
Donghua Xu,Junhao Lin,Shichang Sun,Rui Ma,Mingliang Wang,Jinlong Yang,Juan Luo
Microwave pyrolysis of nitrogen-rich biomass for bio-oil is a green and sustainable pathway to realize energy conversion and produce high-value nitrogenous chemicals. This work selected three typical amino acids (serine (Ser), glutamic acid (Glu), and phenylalanine (Phe)) as nitrogenous model compounds for biomass, and the distribution characteristics and formation mechanisms of the nitrogenous chemicals in bio-oil were studied in depth. Results showed that the amino acid structure and pyrolysis temperature were the crucial factors affecting the distribution and selectivity of nitrogenous chemicals. The nitrogenous chemicals were mainly produced at 200–500 °C from the model amino acids, and the nitrogen in Ser was more prone to accumulating in bio-oil compared with Glu and Phe. At 300 °C, the model amino acids generated numerous amines and cyclic amides through decarboxylation, decarbonylation, and dehydration. Higher temperatures (400 and 500 °C) promoted amines/amides to form nitriles and N-heterocycles, with the releasing of H 2 . Nitriles (including propionitrile and phenylacetonitrile) were typically produced by the straight-chain dehydrogenation of amines. Ser, Glu, and Phe produced N-heterocycles (including pyrazine, pyrrole, 2-pyrrolidone, and indole) based on the cyclization and dehydration between carbonyl and amino compounds, intramolecular dehydration, and cyclization dehydrogenation of phenethylamine, respectively. Finally, the possible formation pathways of the main nitrogenous chemicals were proposed, and the kinetics and thermodynamic analyses were performed through density functional theory (DFT) calculations. The findings could provide theoretical support for the nitrogenous chemicals production from microwave pyrolysis of amino acids and biomass.
研究领域:
能源化学
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Meng Xie,Hai Xu,YiXuan Wang,Helin Pan,Dengle Duan,Bo Niu,Donghui Long,Yayun Zhang
Metal oxides as promoting materials can convert waste plastics into hydrogen (H 2 ) fuel by microwave pyrolysis, solving ecological pollution worldwide, but their tendency of agglomeration and poor porosity limit further applications. Herein, we reported a two-dimensional (2D) metal oxide nanosheets with porous network for recycling high-purity hydrogen and carbon nanotubes from waste plastics in microwave-induced reaction. The 2D porous structure significantly improves the growing space of CNTs and enhances the ability of wave absorption, thereby exhibiting a remarkable H 2 selectivity of 87.5% and high H 2 yield of 60.2 mmol g −1 LDPE, as well as producing high-value CNTs. Moreover, the reaction mechanism for microwave-induced catalytic pyrolysis is proposed, where the Fe 2 O 3 particles on composites facilitated the breakage of C-H bonds, contributing to the generation of H 2 . The current work provides new insights into the recovery of waste plastics by metal oxides through microwave pyrolysis.
研究领域:
环境科学
·
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Yuan Zeng,Yuanyuan Wang,Linyao Ke,Qiuhao Wu,Xiaojie Tian,Liangliang Fan,Kirk Cobb,Yuhuan Liu,Roger Ruan,Yunpu Wang
The pyrolysis of metal soaps to produce hydrocarbon rich fuel has been studied extensively. However, the combined effects of microwave radiation and metal ion types on hydrocarbon production have not been addressed. In this study, the microwave and conventional pyrolysis experiments were conducted on five metal soaps (Li soap, Na soap, K soap, Ca soap, Mg soap). The results demonstrated that the metal ions at the carboxyl end of the soap enhanced the polarity of the reactants, leading to a rapid increase in temperature under microwave conditions. With the ion radius increasing, the heating rate increased gradually. Compared with conventional pyrolysis, microwave pyrolysis exhibited a more rapid heating rate, a higher degree of carbon chain fracture, and a greater abundance of small olefin compounds, which promoted aromatization reaction and the release of CO, H 2 and CH 4 . In addition, the composition of the pyrolysis products derived from different metal soaps is affected by the characteristics of metal ions. As the radius of metal ions increased, the oxygen content in the liquid products decreased gradually, while the carbon content increased. The strengthening effect of microwave was further analyzed. With the increase in the radius of metal ions, the strengthening effect of microwaves on olefins formation was gradually weakened, while the inhibiting effect on alkanes formation was gradually enhanced. The structure of carboxylate network is affected by the radius of metal ions, which results in the regular change of the strengthening effect of microwave on olefins and other products. This study is highly significant in guiding the pyrolysis of soapstock waste to prepare olefins and alkanes with high efficiency and low energy consumption.
研究领域:
能源化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Chen Zeng,ZhiWei Jiang,Yongjian Zeng,Suyu Zhang,Rafael Luque,Kai Yan
H 2 -rich syngas production via microwave-assisted pyrolysis (MAP) of lignocellulosic biomass has recently gained significant attention in biorefineries. Herein, a novel pearl-like calcium oxide (P-CaO) was developed to investigate the dual roles of CaO in H 2 enhancement and CO 2 absorption during MAP of lignocellulosic biomass, dedicated to achieving high production of H 2 -rich syngas. Utilizing a self-constructed MAP system, the different catalytic performance between P-CaO and other metal oxides were examined, revealing that our P-CaO produced the highest H 2 yield (257 NmL/g corn stover , 7.6 times higher than no-catalyst group and 2.2 times higher than commercial CaO group), and lowest CO 2 production (44 NmL/g feedstock ), with syngas purity exceeding 72 vol% at 600°C. This increase in H 2 -rich syngas production demonstrated universal applicability across other biomass feedstocks. Finally, the study delved into the microstructural changes and phase transition mechanisms of P-CaO, shedding insights into gas formation pathways. The P-CaO nanoparticles, with abundant alkaline sites, excellent adsorption capacity and large specific surface area due to aggregate, facilitate the secondary cracking of organic intermediates like phenols, thus promoting the production of H 2 , while CO 2 adsorption derives a favorable shift in the water–gas shift equilibrium. These findings are expected to offer critical insights and serve as a reference for the development of efficient catalysts in the next-generation hydrogen industry.
研究领域:
能源科学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yuchen Jiang,Yuewen Shao,Chao Li,Kang Zhang,Xueming Gao,Lijun Zhang,Shu Zhang,Yi Wang,Xun Hu
Theoretically, any carbonaceous feedstock could be potentially used as a carrier for preparing metal/char composite material. Nonetheless, organics generated from varied feedstocks in pyrolysis might impact distribution of metals in distinct ways. This was investigated herein by microwave pyrolysis of five typical solid wastes (sawdust, pig manure, spirulina, cabbage, and rice) loaded with nickel nitrate at 400 °C and detailed analysis of Ni/char. The results indicated that pig manure contained abundant inorganics (44.2 %), which together with nickel species induced excessive cracking, rendering 18.2 % of carbon content in resulting char (nearly 70.0 % for rice- or sawdust-derived char) and thus little anchoring sites for fixation of nickel species. The in-situ IR characterization of pyrolysis confirmed intensive cracking of the spirulina with high ash content (11.2 %) and unstable organics, which led to a low anchoring sites of Ni. The volatiles from the cabbage of similar property to spirulina also formed less anchoring sites for nickel. In comparison, carbon/oxygen-rich sawdust or rice provided sufficient anchoring sites for nickel, and the dominance of aromatization in pyrolysis resulted in a much higher dispersion of nickel and also a much superior catalytic activity of Ni/char for hydrogenation of vanillin or furfural.
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
Journal of Energy Chemistry
·
2021
·
IF 9.676
Xiangang Lin,Haiwei Du,Daochuan Jiang,Peng Zhang,Zhiwu Yu,Hong Bi,Yupeng Yuan
The n-π* electronic transition in polymeric carbon nitride (PCN) can remarkably harvest visible light, which thus potentially promotes the photocatalytic hydrogen H 2 generation. However, awaking the n-π* electronic transition has proven to be a grand challenge. Herein, we reported on the awakening of n-π* electronic transition by microwave thermolysis of urea pellet, which yielded the PCN with absorption edge of 600 nm, near 140 nm red-shift from 460 nm of pristine PCN. The n-π* electronic transition endows PCN with an increased photocatalytic H 2 generation, with a highest H 2 rate of 61.7 μmol h −1 under visible light exposure, which is near 6 times higher than that by using the PCN from the thermolysis of urea pellets in an electric furnace (10.6 μmol h −1 ). Furthermore, the n-π* transition in PCN leads to the longest wavelength of 535 nm that can initiate H 2 generation, remarkably longer than the absorption edge of pristine PCN (460 nm). This work manifests the advantages of microwave sintering route to awaken the n-π* electronic transition in PCN for an increased photocatalytic performance.
研究领域:
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
WASTE MANAGEMENT
·
2020
·
IF 5.448
Juan Luo,Junhao Lin,Rui Ma,Xing Chen,Shichang Sun,Peixin Zhang,Xiangli Liu
To study the effects of different ash/organics and C/H/O ratios on bio-fuel characteristics and energy efficiency, four kinds of sludge with different properties were used for microwave pyrolysis (800 °C). Moreover, the microwave pyrolysis reaction mechanisms of different sludge were also explored. The results showed that high-ash sludge could accelerate the frequency of polar molecule rotation in the microwave field due to the presence of oxides with dielectric properties in ash, thereby achieving faster heating rates and higher temperatures. However, compared with high-organic sludge, high-ash sludge exhibited lower bio-gas yield and higher bio-char yield. As the H/C ratio increased from 0.127 to 0.148, the bio-gas yield increased from 15.41% to 40.01%, and the content of H 2 in bio-gas and aliphatics in bio-oil increased to 36.69 vol% and 26.54 wt%, respectively. When the O/C ratio was reduced to 1.31, the content of CO and oxygenated compound in bio-oil increased to 31.25 vol% and 40.04 wt%, which lowered the quality of the bio-oil. Those consequences also determined that a mixture of sludge with different ash/organic ratios could be pyrolyzed to obtain high-quality bio-fuels and high energy efficiency. Differences in C/H/O ratios in the mixed sludge greatly affected the microwave pyrolysis heating process, which affected the pyrolysis reactions and the quality of the bio-fuels. Therefore, this study provides a theoretical basis to elevate the quality of bio-fuels and reduce microwave pyrolysis costs.
研究领域:
环境科学
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIORESOURCE TECHNOLOGY
·
2020
·
IF 7.539
Yang An,Arash Tahmasebi,Xiaohui Zhao,Tawanda Matamba,Jianglong Yu
This study addresses the in-situ microwave catalytic reforming of volatile matter from palm kernel shell (PKS) over iron-loaded activated carbon (Fe/AC) catalysts. The impacts of catalyst composition on the secondary gas-phase reactions and distribution of products were studied at 500 °C. It was found that the Fe/AC catalyst promoted the yield of light gases. Using the 1%-Fe/AC catalyst, the yield of gaseous fraction peaked at 37.09 wt%. The selectivity of the deoxygenated products was promoted in the presence of Fe. Catalytic reforming of PKS pyrolysis vapors over Fe/AC drastically enhanced the generation of phenol and H 2 , the concentrations of which reached 75.09 area% and 75.12 vol%, respectively. Catalytic pyrolysis of syringol and guaiacol as model compounds showed that Fe/AC catalyst promoted the demethoxylation and deoxygenation reactions to selectively generate phenol which was explained by oxophilic reactivity of the active Fe sites.
研究领域:
能源与燃料
·
催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Junhao Lin,Shichang Sun,Donghua Xu,Chongwei Cui,Rui Ma,Juan Luo,Lin Fang,Haowen Li
The microwave pyrolysis of biomass and the directional design of biochar structure are examined in this study by exploring the internal connection between energy conversion and biochar structure evolution. Through the optimization of process parameters (microwave power and sample volume), the average utilization efficiency of microwave energy increased from 11.96% to 32.84%, and the specific surface area of the biochar increased from 453.89 m 2 /g to 638.82 m 2 /g. According to the simulation results of the COMSOL Multiphysics software, the distribution of the temperature field was closely related to the evolution of the microwave electric field intensity. The local high temperature areas (hotspots) were primarily located in the center of the biochar, and the temperature distribution gradually decreased from the inside to the outside. The hotspots contributed to the promotion of the conversion of amorphous carbon to graphite carbon. Meanwhile, the graphite carbon with a stronger microwave absorption capacity formed a local hotspot and promoted the growth of the pore structure. The rich pore structure of the biochar facilitated the multiple reflection of microwave energy and prolonged the microwave residence time. Graphite carbon can absorb microwave energy and convert it into heat energy to improve the utilization efficiency of microwave energy. This paper combined the experimental and simulation results to reveal the heat transfer mechanism in the microwave pyrolysis process, which provided a new perspective for the directional reduction of microwave pyrolysis energy consumption and the optimization of the microstructure of biochar.
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
危险品化学品经营许可证（带存储）