ENVIRONMENTAL POLLUTION
·
2022
·
IF 9.988
Lulu Wang,Laihong Shen,Yuyang Long,Dongsheng Shen,Shouxi Jiang
Uncoupling chemical looping gasification (CLG), the organic sulfur evolution was simulated and explored qualitatively and quantitatively using typical sulfur compounds on TG-MS and temperature-programmed fixed bed. The HS radical in the reductive atmosphere easier converted to H 2 S and COS. H 2 O activated the evolution of S which was stably bonded to carbon, and H 2 generated from gasification and oxidation of reductive Fe by H 2 O contributed to the release of sulfur. The proportion of H 2 S released from sulfur compounds was greater than 87% in steam gasification, and more than 60% during CLG. Oxygen carriers promoted the conversion of sulfur to SO 2 in the mid-temperature region (500 °C–700 °C), and H 2 S in the high temperature region (700 °C–900 °C). Sulfur species played a pivotal role in sulfur evolution at low temperature of CLG. The organic sulfur in mercaptan and benzyl were more easily converted and escaped than in thiophene and phenyl . The thermal stability of sulfur species, the presence of steam and OC affected the initial temperature and peak concentration of gas sulfur release as well as sulfur distribution. Consequently, CLG strengthened the sulfur evolution, and made it possible to targeted restructure the distribution of sulfur by regulating process parameters, or blending fuel with different sulfur species for emission reduction, and selective conversion of sulfur.
研究领域:
能源科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
BIOMASS & BIOENERGY
·
2022
·
IF 5.774
Botian Hao,Wei Ning,Donghai Xu,Yu Wang,Yang Guo,Shuzhong Wang
Indole is commonly reported as a N-containing heterocyclic compounds in biomass supercritical water gasification (SCWG), and is difficult to be degraded to small molecule substances. In this work, Ni/AC, Ni–Cu/AC, Ni–Co/AC, Ni–Ce/AC were prepared and tested for catalytic SCWG of indole. The results showed that Ni–Cu/AC had the highest activity for converting indole and producing gases, leading to the highest hydrogen gasification efficiency (135.1%) and carbon gasification efficiency (33.1%). During the catalytic SCWG of indole, the addition of auxiliary metal Cu in multi-component catalyst showed synergistic effects by changing reaction pathways and reaction rates. It significantly promoted water-gas shift and steam reforming reactions, so forming the highest H 2 yield of 2.62 mol mol −1 . Furthermore, large specific surface, Ni reduction and high catalyst stability point to potential advantages of the Ni–Cu/AC catalyst for catalytic SCWG of recalcitrant N-containing compounds.
研究领域:
化学工程
·
能源转换
·
环境科学
·
催化
·
可再生能源
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Lulu Wang,Chenyang Zhou,Laihong Shen,Yuyang Long,Dongsheng Shen
Sulfur impurity in solid fuel should be paid attention to in the thermal process from the perspective of environment and sulfur recovery, especially the auto-thermal oxygen carrier aided pyrolysis/gasification (OCAP). To uncouple the complex sulfur transformation during OCAP of solid fuel and elucidate the main mechanism, several typical model compounds of various functional groups were used to investigate the kinetic analysis and sulfur transformation through temperature-programmed method. The OCAP process consisted of devolatilization and partial gasification. The activation energy of sulfur models devolatilization was less than that of partial gasification, because the required energy was much more to release lattice oxygen from oxygen carrier. Furthermore, the actual oxygen transport capacity of oxygen carrier (OC) redistributed the sulfurous gases. It was found that H 2 S was released earlier than SO 2 . H 2 S release was ascribed to the devolatilization including the reactions between radicals and hydrogen abstracted from base at low temperature (200–300 °C). The different contact modes between sulfur compounds and OC proved that S could be absorbed in the form of iron sulfide and incorporated into char at low temperature but released in the form of SO 2 by OC oxidation at the elevated temperature (400–600 °C), which was in accordance with the kinetic analysis. The migration of sulfur from disulfide had priority over that from monosulfide, and the sulfur connecting with dialkyl (benzyl) was easier to escape than that with diaryl (phenyl) in OCAP process. The fate of sulfur model compounds was conducive to reveal the complex behaviors of solid fuel with different sulfur species, and this work provides evidence to implement the desulfurization and sulfur recovery strategy.
研究领域:
化学工程
·
环境科学
·
能源技术
✓ 已验证
DOI
高影响因子
FUEL
·
2021
·
IF 6.609
Kun Zhao,Xiaojie Fang,Zhen Huang,Guoqiang Wei,Anqing Zheng,Zengli Zhao
Chemical looping gasification provides a novel technology to enable clean conversion of coal with inherent CO 2 capture. In this study, four types of NiFe 2 O 4 and CuFe 2 O 4 synthesized by sol–gel method and solid-phase method were used as oxygen carriers to promote the H 2 production from gasification of lignite. The effects of the types of oxygen carrier and oxygen carrier to coal (O/C) ratio on chemical looping gasification of lignite were first investigated by a thermogravimetric analyzer (TGA) combing with various analytical methods. The results show that, among four types of oxygen carrier, the NiFe 2 O 4 synthesized by sol–gel method exhibits the highest gasification reactivity with lignite char at an O/C ratio of 1, since its highly cubic spinel structure is beneficial to improve the mobility of lattice oxygen. Furthermore, the operating conditions for chemical looping gasification of lignite were optimized and the gasification performance of four types oxygen carriers was compared by using a fixed bed reactor. It is found that NiFe 2 O 4 synthesized by sol–gel method exhibits the highest total gas yield of 24.47 mol/kg and H 2 /CO ratio of 0.77 during chemical looping gasification of lignite under the optimal operating conditions, ascribed to Fe-Ni synergistic effect which provided higher gasification reactivity with lignite char. The addition of steam drastically improves the total gas yield and H 2 /CO ratio of syngas from 24.47 mol/kg and 0.77 to 64.98 mol/kg and 2.79, suggesting that the H 2 /CO ratio of syngas can be flexibly adjusted to meet the need of downstream process via controlling the amount of steam added. These findings provide an efficient method to obtain H 2 -rich syngas via chemical looping gasification of lignite.
研究领域:
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Chenyu Wang,Xiaolong Ling,Chaoyue Wu,Chao He,Biao Gui,Weibo Sun
Phosphorus is a very important resource, and dewatered cyanobacteria contains a large amount of it. Basic additives, such as KOH, are often used to promote hydrogen production during supercritical water gasification (SCWG) of biomass, but their effects phosphorus transformation have rarely been investigated. In this study, SCWG of dewatered cyanobacteria with potassium salt and KOH was conducted in autoclave at 400 °C for 10 min, to investigate the effect of K + on the transformation of phosphorus under neutral and alkaline conditions. Results showed that K + increased the proportion of phosphorus in the solid phase from 88.4% to 90.8–98.3%. Furthermore, K + could promote the transformation of iron-combined phosphorus to calcium-combined phosphorus and occluded phosphate. Only when the reaction environment was alkaline, the proportion of phosphorus in the solid phase was significantly reduced to a minimum of 26.1%. When the amount of OH − was sufficient, can this part of phosphorus and organic phosphorus , which was decomposed and transformed by the promotion of OH − , be transferred to the liquid products. Results from this study laid a foundation simultaneously for hydrogen production and phosphorus recovery more environmentally and high-effectively.
研究领域:
环境科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2018
·
IF 4.229
Long-Fei Xie,Pei-Gao Duan,Jia-Li Jiao,Yu-Ping Xu
A series of Ni catalysts with different zeolites were prepared by wet impregnation method and used to catalyze supercritical water gasification (SCWG) of microalgae for production of hydrogen-rich fuel gas under conditions of 430 °C, 60 min, ρ H₂O = 0.162 g/cm 3 , 2 g/g Ni/zeolites. Compared with noncatalytic SCWG, the presence of Ni/zeolite could increase the hydrogen gasification efficiency and carbon gasification efficiency by promoting water–gas shift and steam reforming reactions which are mainly affected by the amount of strong acid sites and Ni, respectively. The highest carbon gasification efficiency (CGE) and hydrogen gasification efficiency (HGE) of 23.61% and 23.55% were achieved with Ni/HY (Na 2 O, 0.8%). The gaseous produced mainly consisted of H 2 and CO 2 . The H 2 content in the gaseous products varied from 27.15 to 40.51% depending on the Ni/zeolites and increased with increasing the SiO 2 /Al 2 O 3 molar ratio of HZSM-5, which is 2.3–3.6 times higher than that of produced without catalyst. The H 2 yield varied between 2.57 and 3.61 mmol/g depending on the Ni/zeolites and increased from 2.19 to 5.61 mmol/g with increasing the SiO 2 /Al 2 O 3 molar ratio from 50:1 to 170:1, which is 3.6–7.8 times higher than that of produced without catalyst. Coke formation, surface area loss, and sintering of Ni could decrease the activity of the Ni/zeolites.
研究领域:
能源生物学
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SUPERCRITICAL FLUIDS
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2020
·
IF 3.744
Jie Sun,Lujiang Xu,Guo-hua Dong,Sonil Nanda,Hu Li,Zhen Fang,Janusz A. Kozinski,Ajay K. Dalai
Nickel-based catalysts with different supports and cobalt loadings were synthesized for hydrothermal gasification of cellulose at 350 °C. The activity of Ni catalysts was found in the order of Al 2 O 3 > spent bleaching clay ash > SiO 2 with H 2 yield of 80.6%, 69.0% and 57.0%. When 6 wt. % Co was added, 10Ni-6Co/Al 2 O 3 showed the highest H 2 yield of 88.4% i.e., 1.44 times that without Co addition. Catalysts were characterized by NH 3 -TPD, TPR, XRD, BET and XPS, showing that Ni-Co alloy formation promoted H 2 production. Single-factor experiments were conducted to study variables in the presence of 10Ni-6Co/Al 2 O 3 with the selected conditions of 0.5 g biomass and 20 min at 350 °C (achieving 94.9% H 2 yield from cellulose) for gasification of rice straw, peanut shell and cotton straw with the increase in H 2 yield by 51.4, 76.0 and 67.8 times. Ni-Co/Al 2 O 3 catalysts enhanced hydrothermal gasification of actual agricultural residues.
研究领域:
化学工程
·
环境科学
·
催化
·
可再生能源
✓ 已验证
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Yinhai Pan,Du Wei,Shuo Yao,Haijun Zhang,Quanzhi Tian
Coal gasification slag (CGS) is rich in Li and Ga. However, few studies have focused on the extraction of Li and Ga from CGS. In the present study, the leaching of Li and Ga from CGS calcined with the alkali reagents including NaOH, KOH, Na 2 O 2 , Na 2 CO 3 and K 2 CO 3 were studied through water leaching and solid characterizations including XRD, TG-DSC and NMR. The best leaching percentages of Li and Ga from NaOH-, KOH-, Na 2 O 2 -, Na 2 CO 3 - and K 2 CO 3 -roasted products were 40.81% and 47.89%, 41.19% and 31.60%, 28.04% and 52.40%, 28.21% and 48.58%, and 34.29% and 38.61%, respectively, showing Li and Ga are difficult to be leached out. It has been proven that the formation of insoluble crystal substances (such as NaAlSiO 4 ) in alkali fusion products inhibits the leaching of Li and Ga. In addition, Li and Ga can be released from the insoluble crystal substances due to Na 2 SiO 3 in alkali fusion products can promote the dissolution of insoluble crystal substances into SiO 4 and AlO 4 species, which can improve the leaching of Li and Ga. However, part of the released Li and Ga are stabled in the structure of amorphous substances generated by SiO 4 and AlO 4 species in the form of isomorphism, reducing the leaching of Li and Ga. Thus, this work would provide guidance for the leaching of Li and Ga from CGS.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
WASTE MANAGEMENT
·
2019
·
IF 5.431
Chenyu Wang,Wei Zhu,Hao Zhang,Cheng Chen,Xihui Fan,Ying Su
The hydrothermal gasification of dewatered sewage sludge converts waste into syngas fuel (gas containing H 2 , CH 4 , CO, and CO 2 ), but the formation of char and tar by a side reaction restricts practical applications. In this study, the formation of char/tar by the hydrothermal gasification of dewatered sewage sludge at 300–400 °C for 5–90 min with a heating rate of 8–50 °C/min is investigated. The results showed that the formation of tar/char reached equilibrium after 30 min, and an increase in the temperature and heating rate reduced the char yield. However, a higher tar yield was achieved at the highest temperature. Experiments on sludge with different moisture contents were also conducted, and the formation of char/tar was inhibited at a higher moisture content. The addition of NaOH and H 2 O 2 can effectively reduce the char and tar yields, respectively. A lumped kinetic model for describing carbon conversion during the hydrothermal gasification of sewage sludge was developed to elucidate the char/tar formation mechanism. The experimental data were used to determine the model parameters, and the fitting results showed that solid–solid conversion from organic matter in sludge was the predominant char/tar formation pathway, with an activation energy of 7.1 kJ/mol. The experiments using the model compounds indicated that humus and protein are the main precursors of char and tar, respectively. This study provides insights for understanding the formation of char/tar from sewage sludge following hydrothermal gasification, which is vital for controlling the formation of char and tar to improve the gasification efficiency.
研究领域:
环境科学
·
能源工程
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2024
·
IF 6.7
Xin Yang,Caixia Yue,Yahui Wang,Jiancheng Wang,Liping Chang,Weiren Bao
Although coal gasification is recognized as a core technology for clean coal utilization, S and Hg can migrate to gas, wastewater, and slag during the gasification process, causing environmental pollution. It is well known that S and Hg have a strong affinity. Therefore, the interaction between S and Hg during the gasification process warrants further investigation. In this study, the occurrence modes and distribution characteristics of S and Hg in gasification slag were systematically investigated using multiple treatments and various characterization techniques. The results showed that sulfur in the gasification slag exists predominantly as organic sulfur, while mercury mainly exists as HgS/silicate-bound Hg. Although the relative enrichment index of Hg (RE < 0.7) indicates its high volatility, a more pronounced enrichment effect for mercury of fine slag was indicated by its much higher RE than coarse slag. When exploring the relationship among the contents of C, S, and Hg and specific surface area in gasification slag, it was found that the correlation between S and Hg content in fine slag was the strongest, with a correlation coefficient (R 2 ) of 0.96, indicating a significant influence of sulfur content in fine slag on mercury content. Additionally, it was observed that the S and Hg contents in gasification slag increased with the decrease of particle size and density. These results provide an important understanding of the distribution, migration, and transformation behavior of S and Hg during coal gasification, as well as a certain theoretical support and technical basis for the resource utilization of gasification slag.
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
JOURNAL OF THE ENERGY INSTITUTE
·
2022
·
IF 6.47
Ming Zhao,Jun Sun,Muhammad Asif Akhtar,Shu Zhang,Juntao Wei,Deliang Xu,Xun Hu,Mortaza Gholizadeh,Hong Zhang
Waste wood-based panels (WBPs) with high nitrogen content is a typical kind of industrial biomass waste, and a large amount of NO x will be generated during its incineration treatment. Therefore, this work is aimed at studying the retention and conversion characteristics of nitrogen in gasification char of WBPs. For fixing more nitrogen in char, co-gasification experiments of fiberboard (FB, the main kind of WBPs) and glucose were carried out using a fixed bed reactor , and the subsequent analysis was conducted by element analyzer, XPS , SEM and BET. The results show that the addition of glucose could efficiently fix nitrogen in gasification char , the nitrogen retention ratios of FB-glucose char under N 2 and CO 2 atmosphere were 2.6–5.6 times and 1.4–2.0 times greater than that of individual FB char, respectively, due to the enhanced Maillard reaction. As the temperature increased, the portions of N-5 and N-6 decreased along with the formation of N-Q and N–O. Moreover, the addition of glucose led to the delay of the conversion from N-5 and N-6 to N-Q and N–O in char. BET results demonstrate that the surface area and total pore volume of co-gasified char were significantly lower than those of individual FB gasified char. The glucose had a negative effect on the pore structure development of co-gasified char. These results could offer strategies on reducing NO x emission in biomass thermal conversion and regulating nitrogen functional groups in biochar.
研究领域:
能源与环境科学
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
FOOD RESEARCH INTERNATIONAL
·
2023
·
IF 8.1
Rong-Jian Dong,Xie-Huang Sheng,Qian-Tu Xie,Xiaolin Huang,Fujie Yan,Songbai Liu
Yellow tea, a unique type of tea in China which is characterized with yellow color, has gained increasing popularity due to its pleasant taste. However, transformation of aroma compounds during sealed yellowing has been poorly understood. Results of sensory evaluation exhibited that yellowing time was the key factor for flavor and fragrance formation. A total of 52 volatile components during sealed yellowing process of Pingyang yellow soup were further collected and analyzed. The results demonstrated that the sealed yellowing process significantly increased the ratio of alcohol and aldehyde compounds in the aroma volatiles of yellow tea, which were primarily composed of geraniol, linalool, phenylacetaldehyde, linalool oxide and cis -3-hexenol, and their proportion increased with the prolongation of sealed yellowing. Mechanistic speculation revealed that the sealed yellowing process promoted release of alcoholic aroma compounds from their glycoside precursors and enhanced Strecker and oxidative degradation. This study revealed the transformation mechanism of aroma profile during the sealed yellowing process, which would facilitate processing of yellow tea.
研究领域:
食品科学
·
植物学
✓ 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）