JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2024
·
IF 5.8
Yang-Yang Xu,Xing Fan,Feng-Yun Ma,Hai-Xu Zou,Xian-Yong Wei
Directly converting lignite into arenes as commodity chemicals and drop-in fuels is a highly desirable target for researchers. However, this is severely limited by the presence of stable inter unit C-O linkages in lignite. Herein, a highly active catalyst, Co-MoS 2 , has been designed and prepared to be used for the selective catalytic cleavage of inter unit C-O bridged bonds (BBs) in the conversion of Naomaohu (NMH), a lignite, to yield arenes. Both catalytic hydrogenation conversion (CHC) and thermal dissolution (a non-catalytic process, named NCHC) of NMH were conducted using n-hexane as the solvent. The soluble fractions from the first stage of NCHC (SF NCHC-1 ) and CHC (SF CHC-1 ), as well as the second stage of NCHC (SF NCHC-2 ) and CHC (SF CHC-2 ) were obtained using the same solvent. After the first-stage catalytic treatment, the relative contents of arenes and alkanes in SF CHC-1 increased by 16.7 % and 9.3 %, respectively, compared to those in SF NCHC-1 , and the relative content of oxygen-containing compounds (OCCs), such as alcohols, phenols , esters, ketones , acids, and furans, decreased by 13.2 %. For the second-stage conversion, the relative contents of arenes and alkanes in SF CHC-2 were 53.5 % and 15.5 % higher than those in SF NCHC-2 , and the relative contents of OCCs was only 6.6 % in SF CHC-2 . The catalytic mechanisms of cleavage of C-O BBs and deoxygenation were proposed based on the CHC of model compounds and density functional theory (DFT) calculation. The adsorption of OCCs and the activation of released hydrogen radical (H·) by Co-MoS 2 , followed by H· addition to the carbon atom connected to oxygen in C-O BBs and oxygen-containing functional groups, are crucial for the cleavage of C-O BBs and formation of deoxygenated compounds, particularly arenes.
研究领域:
化学工程
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催化科学
✓ 已验证
产品关联
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
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 44
·期 32
·13755-13763
·
IF 3.288
Xia Wang,Wulan Zeng,Wenjing Liu,Xiaoyu Cao,Chunhui Hou,Qi Ding,Yaxuan Lü
The design and development of low-cost sorbents is vital for CO2 capture from flue gases. In this study, the lignite char from Ordos coal (SE) was treated by a one-step KOH activation method to prepare microporous activated carbons for CO2 adsorption. The textural pore properties, surface functional groups and element contents of SE before and after activation were characterized and discussed; the effects of the mass ratio of KOH to SE, activation temperature and time, as well as the adsorption temperature on CO2 adsorption for prepared porous sorbents were investigated and optimized; the isosteric heat of adsorption and adsorption kinetics for the optimized sorbent were further calculated and fitted. When the mass ratio of KOH to SE was 1 : 1, the activation temperature and time were 700 °C and 120 min respectively, and the sorbent of K/SE700(120) showed an adsorption capacity of 1.35 mmol g−1 at 20 °C, which dropped by 2.96% after ten regenerations. The Langmuir adsorption isotherms fitted the adsorption data of K/SE700(120) well, and the isosteric heats of adsorption were 11–13 kJ mol−1, showing the physisorption characteristic. In addition, the good fit of the adsorption data to the Avrami model suggested that there are multiple adsorption routes for K/SE700(120).
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Yan-Na Han,Zong-Qing Bai,Jun-Jie Liao,Jin Bai,Xin Dai,Xiao Li,Jun-Li Xu,Wen Li
Oxygen functional groups as primary adsorption site of water are one of key factors controlling water re-adsorption and drying behaviors of brown coal . The dewatering energy of brown coal because of different oxygen functional groups is still unclear. Thus, two kinds of oxidized brown coal samples carrying more phenolic hydroxyl or carboxyl groups with similar pore structures were chosen. The concentrations of different water forms of the samples were determined from the moisture holding capacity at constant humidity and temperature and from the results of dewatering experiments analyzed by thermogravimetry coupled with differential scanning calorimetry . The results showed that the concentrations of three forms of water, i.e. free water, capillary water , and molecular water, showed good correlations with concentration of carboxyl groups. Comparison of 1 H NMR analysis of dried and moisturized samples showed that the types of oxygen functional groups predominantly affected the water environment in coal. IR spectra of dried and adsorbed D 2 O samples showed that OH–π hydrogen bond due to carboxyl groups was easier broken than that due to phenolic hydroxyl groups . The water desorption energy of primary site and dewatering energy of samples with more carboxyl groups were lower than that of samples with more phenolic hydroxyl groups, because hydrogen bonding energy of water bonded to hydroxyl oxygen of carboxyl groups was lower than that of water bonded to hydroxyl oxygen of phenolic hydroxyl groups.
研究领域:
能源科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2017
·
IF 3.154
Yafu Tang,Xinying Wang,Yuechao Yang,Bin Gao,Yongshan Wan,Yuncong C. Li,Dongdong Cheng
In this work, lignite, a low-grade coal, was modified using the solid-phase activation method with the aid of a Pd/CeO2 nanoparticle catalyst to improve its pore structure and nutrient absorption. Results indicate that the adsorption ability of the activated lignite to NO3–, NH4+, H2PO4–, and K+ was significantly higher than that of raw lignite. The activated lignite was successfully combined with the polymeric slow-release fertilizer, which exhibits typical slow-release behavior, to prepare the super large granular activated lignite slow-release fertilizer (SAF). In addition to the slow-release ability, the SAF showed excellent water-retention capabilities. Soil column leaching experiments further confirmed the slow-release characteristics of the SAF with fertilizer nutrient loss greatly reduced in comparison to traditional and slow-release fertilizers. Furthermore, field tests of the SAF in an orchard showed that the novel SAF was better than other tested fertilizers in improve the growth of young apple trees. Findings from this study suggest that the newly developed SAF has great potential to be used in apple cultivation and production systems in the future.
研究领域:
农业科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2020
·
IF 3.795
Hongliang Li,Rui Li,Mengmeng Wang,Jianbo Li,Yafeng Fu,Benkang Zhu
Previous studies verified that the moisture adsorption on the lignite can be reduced by adsorption of surfactant on the surface. However, these surfactant adsorption processes were realized in aqueous solutions, result in a great deal of water bring into the system. It seems that the surfactant is affinity to the surface of lignite and the adsorption can be realized in dry condition with a well-designed method. In this study, we propose a method to reduce the adsorption of moisture by lignite in dry condition, by mechanically mixing it with a surfactant in a ball mill. The surfactant is adsorbed by the lignite surface toward due to the electrostatic interactions during the mixing process, which makes the lignite surface hydrophobic. Untreated and treated samples of lignite were exposed in an environment of 100% relative humidity, maintained at 20 °C, for 36 h. Compared to the untreated sample, the moisture content in the treated sample decreased from 25.9% to 11.6%. This reduction in the adsorbed moisture content is due to the modification of the hydrophobicity of the original sample. The particle size of the lignite decreases significantly after ball milling. As the particle size required for the commercial utilisation of lignite is usually low, the proposed method can be applied after the dry beneficiation process.
研究领域:
环境科学
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材料科学
·
化学工程
·
能源技术
✓ 已验证
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Zhiyuan Zhang,Guixia Fan,Guoli Zhou,Daoguang Teng,Hongyan Nan,Peng Li,Yijun Cao,Jiongtian Liu
Germanium, a critical metal, is predominantly located in lignite and lead–zinc ore. The germanium was commonly extracted from the fly ash of germanium-rich lignite (GRL), however, facing the challenges of specific combustion conditions, low lignite’s thermal efficiency and value, high CO 2 emissions, and waste acid treatment. Therefore, in this work, a novel method for directly leaching germanium from the GRL was proposed, facilitating low-carbon extraction under mild conditions, and reducing lignite loss during leaching process. Results showed that leaching germanium from the GRL using thionyl chloride achieved the goals of “kill two birds with one stone”, i.e. , leaching efficiency of germanium above 95 wt % and recovery yield of lignite over 95 wt %. Specifically, the theoretical leaching efficiency of germanium reached 99.60 wt % while the recovery yield of lignite reached 86.35 wt %, at the temperature of 20 °C, liquid–solid ratio of 4 mL/g, and leaching time of 6 h. Most of the leached germanium was remained in the aqueous phase after the leaching solution was quenched, facilitating the subsequent separation of germanium. In this study, efficient extraction of germanium from the GRL was achieved with a high recovery yield of lignite, preserving the matrix structure and main composition of lignite. Therefore, this method provides a feasible way for efficient extraction of germanium from lignite with low-carbon emission under mild condition.
研究领域:
材料科学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xiaofang Zhang,Yuhuan Li,Yang He,Debin Kong,Bern Klein,Shenghua Yin,Hongyu Zhao
Activated carbon plays an important role in the field of wastewater treatment due to its excellent adsorption, but improving the recovery and utilization efficiency of activated carbon is a major challenge for its application. In this study, lignite (LC) and poplar leaves (PL) were used as raw materials to prepare magnetic activated carbon (MAC) by co-pyrolysis and char activation modification. The adsorption performance of the product was studied. The results showed that with different blending ratios of LC and PL, a large amount of alkali metal oxides contained in PL had different promoting effects on the pyrolysis of LC. When the mass ratio of LC to PL in the mixture was 3:2, the experimental value of hydrocarbons in the obtained tar reached 53.00%, which was 7.20% higher than the calculated value. The optimal preparation conditions of MAC were determined. Under the conditions of activation temperature of 700 °C, activation time of 2 h, ZnCl 2 mass fraction of 30%, impregnation liquid–solid ratio of 3:1 and impregnation time of 16 h, the activated carbon exhibits a relatively desirable performance. The obtained products were characterized by VSM, XRD, FT-IR, N 2 adsorption and SEM. As a result, the obtained MAC exhibits a better porous structure and higher specific surface area, and Fe 3 O 4 was observed on the surface of the MAC. The adsorption performance of coking wastewater by MAC was studied. We demonstrate that the prepared MAC could effectively adsorb organic matter in wastewater. After MAC was used to adsorb the coking wastewater for 3 h, the COD concentration in the wastewater decreased from 280 to 60 mg/L, and the MAC could be effectively recovered by magnets after adsorption.
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
FUEL
·
2023
·
IF 7.4
Xiao-Yan Zhao,Xue-Yu Ren,Yan-Jun Wang,Jing-Pei Cao,Zi-Meng He,Nai-Yu Yao,Hong-Cun Bai,Hou-Luo Cong
Direct conversion of lignite into light aromatics via catalytic fast pyrolysis is a great challenge because of severe catalyst deactivation and low aromatics yield. The tandem catalysis (1Zn@MCM-41 and ZSM-5) system was employed to promote the conversion of thermally-derived volatiles of lignite into aromatics at 600 °C. The mesoporous Zn-incorporated MCM-41 (xZn@MCM-41) with different doping amount of Zn was prepared with a one-pot hydrothermal procedure. The structure and the dispersion of Zn species of 1Zn@MCM-41 were systematically studied with XRD, SEM, BET, NH 3 -TPD and so on. The presence of 1Zn@MCM-41 significantly expands the lifetime of the microporous ZSM-5. Meanwhile, the yield of aromatics, especially benzene, is also increased to some extent. The content of the long-chain hydrocarbons and the phenolic compounds are decreased significantly after being cracked by the mesoporous 1Zn@MCM-41. More small molecules are able to contact with the active sites located in the micropores of ZSM-5 with the presence of Zn@MCM-41. In addition, the ZSM-5 in the tandem catalysts system presents an excellent stability. Therefore, this meso -microporous tandem catalysis system promotes the preferential cracking of macromolecular compounds, the cracked small molecules generated from which then contact with ZSM-5 to produce aromatics. This work provides a new perspective for the gradient catalyzing lignite-derived volatiles over a tandem catalysis system.
研究领域:
能源化学
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2019
·
IF 5.128
Tengfei Yang,Congcong Liu,Chuan Li,Liyong Gan,Wenan Deng,Qingshan Niu
Nickel sulfide is regarded as one of the most promising substitutes for the best-performing disposable molybdenum catalyst in the hydrogenolysis of lignite and heavy residue, but its practical application is hindered severely by insufficient catalytic activity and a prohibitively large dosage. Herein, we report that the issues of activity and cost of nickel sulfide can be addressed simultaneously by employing a combination of iron incorporation and a dispersing strategy via oil-soluble ligands. Motivated by first-principles calculations where iron incorporation in nickel sulfide would lead to a better activity towards the rate-limiting step of hydrogenolysis compared with nickel sulfide alone, we successfully prepared a well-dispersed Fe-Ni-S catalyst by coordinating active metal salts with carboxylate ligands and a subsequent essential sulfurization. The synthesized Fe-Ni-S catalyst outperformed not only the monometallic nickel catalyst but also the commercial molybdenum catalyst in the hydrogenolysis of lignite and heavy residue, and exhibited a high conversion efficiency, hydrogen consumption, hydrogen/carbon product atomic ratio, and dispersibility of solid residues, with an economic nickel dosage of as low as ~250 μg·g −1 . Structural changes of raw coal and solid residues further confirmed the role of the Fe-Ni-S catalyst in facilitating the hydrogenolysis of lignite and heavy residue.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2012
·
IF 2.237
Wenhua Wang,Yucui Hou,Weize Wu,Muge Niu,Weina Liu
The oxidation of coal to produce high-valued benzene polycarboxylic acids (BPCAs), which are obtained currently from diminishing petroleum reserves, is a promising industrial process of the future. Up to now, the yield distribution of BPCAs has not been studied in detail and the mechanism of coal oxidation to BPCAs remains unclear. In this study, Huolinhe lignite was oxidized in a batch reactor by alkali-oxygen oxidation. All 12 kinds of BPCAs obtained were quantified by a new established method. Effects of alkali/coal mass ratio, reaction temperature, initial oxygen pressure, and reaction time on the yield distribution of BPCAs were studied for the first time. The results indicate that BPCAs with four or five carboxyls are the predominant products, and BPCAs with one or two carboxyls are formed in a relatively short time; moreover, the formation of BPCAs with more carboxyls is relatively more sensitive to the salting out effect. CP/MAS 13C NMR spectra and oxidation of model compounds show that phenolic, ether-substituted aromatic, ether, and aldehyde groups are easily converted and that water-soluble acids (WSA) are formed rapidly and largely due to the breakage of these bonds. The step from WSA to BPCAs is relatively slow mainly due to the inertia of the aromatic clusters with attached carboxyls or carboxylate. On the whole, the BPCAs are derived from aromatic clusters through the oxidation of condensed benzene rings, bridges, or peripheral groups that are attached to the aromatic clusters. Possible mother units for BPCAs in the lignite are suggested based on the generally agreed lignite structure.
研究领域:
化学工程
·
煤炭化学
✓ 已验证
产品关联
DOI
高影响因子
Minerals
·
2022
·Vol. 12
·期 6
·665
·
IF 2.818
Xiaofang Zhang,Yuhuan Li,Yang He,Debin Kong,Bern Klein,Shenghua Yin,Hongyu Zhao
Adsorption with activated carbon (AC) is an important method for the treatment of heavy metal wastewater, but there are still certain challenges in the separation and reuse of activated carbon. The preparation of magnetic activated carbon (MAC) by modifying AC is one of the effective means to realize the separation of AC from solution after the adsorption process. In this work, lignite and poplar leaves were used as raw materials for co-pyrolysis, and the co-pyrolysis char was activated and modified to prepare MAC. The structure and properties were characterized by VSM, N2adsorption, SEM, XRD, and FT-IR. At the same time, the adsorption performance of MAC on wastewater containing Pb and Cd ions was studied. The results show that the prepared MAC contains Fe3O4, and the saturation magnetization (Ms) of the MAC is 13.83 emu/g; the specific surface area of the MAC is 805.86 m2/g, and the micropore volume is 0.23 cm3/g; the MAC exhibited a good porous structure. When the pH value of the solution was 5, the adsorption time was 120 min, the dosage of MAC was 4 g/L, the initial concentration of Pb ion solution was 50 mg/L, and that of Cd ion solution was 25 mg/L, and the adsorption temperature was 30 °C, the adsorption efficiency of Pb, Cd ions were 84.40 and 78.80%, respectively, and the adsorption capacities were 10.55 and 4.93 mg/g, respectively. The adsorption of Pb and Cd ions by MAC conforms to the Langmuir adsorption model, which is a monolayer adsorption. The adsorption process is mainly chemical adsorption, which can be better described by the pseudo-second-order model. The adsorption thermodynamic analysis showed that the adsorption of Pb and Cd ions by MAC was a spontaneous reaction, and the higher the temperature, the stronger the spontaneity.Keywords:lignite;poplar leaves;magnetic activated carbon;heavy metal ions;adsorption mechanism
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
危险品化学品经营许可证（带存储）