JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Jiajia Ma,Zhiheng Ye,Jie Zhou,Zhong-Ting Hu,Qianqian Wang,Junliang Wang,Zhiyan Pan,Mian Hu
In this study, the influences of soybean straw (SS) to spirulina platensis (SP) mass ratios and pyrolysis temperature on the evolution properties of N-containing species in pyrolytic tri-products and the nitrogen migration mechanism and involved chemical reactions during the co-pyrolysis processes were comprehensively investigated. Results indicated that co-pyrolysis of SS ang SP significantly facilitated the transformation of nitrogen into N bio-oil and N char from N gas . Increasing the amount of SP led to a decrease in the concentration of NH 3 and HCN in N gas , while their concentrations increased gradually with temperature increasing. NH 3 and HCN formation was due to H radicals attacking the N-sites of N-heterocyclic, with NH 3 formation being more strongly influenced by this process. Regarding N char , increasing the ratio of SP enhanced nitrogen incorporation reactions and promoted formation of pyridinic-N and pyrrolic-N. Conversely, decreasing the ratio of SP enhanced hydrogenation and condensation reactions, which favored the formation of quaternary-N. With increasing temperature, protein-N decomposed significantly, while pyridinic-N, pyrrolic-N, and quaternary-N remained stable. Additionally, pyridinic-N can convert to quaternary-N at temperature > 500 °C. Increasing the SP ratio greatly decreased oxygenates content while increased that of N-containing compounds in N bio-oil . The content of heterocycle-N (34.31 %) and nitriles (9.22 %) in bio-oil peaked at a ratio of 1:3, attributed to SP promoted the condensation and diazotization cyclization reactions. Furthermore, increasing the reaction temperature (from 400 to 800 °C) significantly increased the yields of heterocycles-N, while the yields of amines and amides decreased sharply due to dehydration reaction. As analyzed above, the possible nitrogen migration mechanism and involved chemical reactions were elucidated. These findings provides insights for generating high value-added N-containing chemicals and N-doped carbon materials during N-rich pyrolysis.
研究领域:
能源与环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Li Zhang,Yi Wei,Yuan Yin,Xiang Liu,Shu Zhang,Lei Shi,Juntao Wei,Hong Zhang,Alexander N. Kozlov,Maxim V. Penzik,Deliang Xu
Nitrogen migration and transformation have been extensively studied during the thermochemical conversion of biomass, particularly N-rich biomass, due to concerns about nitrogen oxides pollution or the preparation of N-doped carbon materials. Nitrogen in fiberboard was extracted into an aqueous solution through low-temperature hydrothermal treatment to prepare the recycled aqueous solution. Subsequently, hydrothermal conversions of glucose and xylose were conducted in the recycled solution. The migration and transformation of nitrogen between hydrochars and aqueous phase were investigated. The results showed that the nitrogen retention rates of glucose hydrochars were higher than those of xylose hydrochars at low temperatures. As the temperature increased, the nitrogen retention rates of glucose and xylose hydrochars tended to converge, reaching their highest value at 220 °C. In hydrochars, nitrogen had a high content and was widely distributed on the surface of the carbon microspheres. The nitrogen content did not change significantly with increasing temperatures, but the nitrogen functional groups tended to become more thermostable. In addition, the char yields of glucose and xylose in fiberboard recycled solution were significantly higher than that in the ultrapure water at low temperatures, which indicates that the introduction of nitrogen promotes the formation of hydrochars. These findings favored the study on the nitrogen migration and transformation during hydrothermal conversions of lignocellulose in a N-rich environment.
研究领域:
能源与环境科学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Chemistry
·
2022
·
IF 13.599
Shanjian Liu,An Zhao,Jia Liu,Mengqian Yin,Fupeng Huang,Dongmei Bi
This study aimed to investigate the mechanism of nitrogen doping, migration, and conversion during ammonia torrefaction and also explore the evolution law of the chemical structure of cellulose. The results showed that the ammonia torrefaction pretreatment could significantly optimize the distribution of nitrogen and oxygen elements in cellulose. The carbon skeleton first captured the active nitrogenous radicals to form –NH n -N, and pyridine-N and pyrrole-N originated from the conversion of –NH n -N. The existence of C O played a major role in the immobilization of nitrogen. The nitrogen in bio-oil exists mainly in the form of five- and six-membered heterocycles. The correlation analysis showed that the main precursors for the formation of nitrogenous heterocyclic compounds were five-membered O-heterocyclic compounds. Finally, the product distribution characteristics in the torrefaction-pyrolysis systems were summarized, and the nitrogen doping and conversion mechanisms were proposed. This study expanded the boundaries of cellulose pretreatment and the production of high-value chemicals.
研究领域:
生物质能
·
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY
·
2024
·
IF 9
Shuai Guo,Yu Wang,Li Yang,Baizhong Sun,Hongwei Qu,Xingcan Li,Deng Zhao
The study used ReaxFF MD (Reactive Force Field Molecular Dynamics) to investigate the migration behavior and mechanisms of nitrogen in the pyrolysis process of biomass, specifically focusing on the effect of the alkali metal potassium on the main nitrogen-containing substance, proteins. This research primarily centers on the conversion mechanisms of nitrogen in the three-phase products (char, tar, and gas) during the pyrolysis of proteins, as well as the impact on NH 3 formation. The findings reveal several key insights: First, the introduction of potassium significantly enhances the cleavage activity of protein macromolecules by promoting the breaking of carbon-carbon and carbon-nitrogen bonds, which accelerates the degradation process of protein molecules and subsequently increases the conversion rate of nitrogen from proteins to the nitrogen in char, tar, and gas. Second, the addition of potassium alters the sources of gaseous nitrogen (gas-N); initially derived mainly from the secondary cracking of tar nitrogen (tar-N), gas-N predominantly originates from the conversion of char nitrogen (char-N) under the influence of potassium. Lastly, the introduction of potassium affects NH 3 production by significantly altering the trend of nitrogen-hydrogen bond variation during the pyrolysis of proteins. This is primarily attributed to potassium's facilitation of dehydration reactions, which disrupt nitrogen-hydrogen bonds during protein pyrolysis. Additionally, it allows NH 3 produced in the later stages of pyrolysis to participate in the formation of other nitrogen-containing compounds, particularly HCN. Potassium also promotes the dehydrogenation of the large number of HCN molecules generated during protein pyrolysis, forming CN radicals that subsequently react with NH 3 to produce new compounds. This is the main reason for the variation in NH 3 yield.
研究领域:
能源与环境科学
·
化学工程
·
计算化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2024
·
IF 5.8
Zijun Dong,Yi Wei,Yujie Chen,Li Zhang,Deliang Xu,Guiying Lin,Bin Li,Shu Zhang,Juntao Wei,Muhammad Asif Akhtar,Jun Sun
Investigating how cellulose, xylan, and lignin affect nitrogen’s migration and transformation during pyrolysis is valuable, as lignocellulose pyrolysis can markedly alter these processes. This paper studied the co-pyrolysis of cellulose/xylan/lignin with urea formaldehyde (UF) using a thermogravimetric (TG) analyzer to assess their interactions. Furthermore, co-pyrolysis experiments of cellulose/xylan/lignin with UF at different temperatures were conducted in a fixed-bed reactor. TG analysis indicated that UF co-pyrolyzing with cellulose/xylan enhanced lower-temperature reactions, while it inhibited reactions when co-pyrolyzed with lignin. Co-pyrolysis studies showed xylan addition significantly enhanced char nitrogen retention, whereas lignin promoted nitrogen volatilization. Cellulose, xylan, or lignin incorporation yielded chars with more stable heterocyclic-N. Nitrogen preferentially migrated into the tars within a temperature range of 400 °C to 600 °C, and heterocyclic-N synthesis was efficient between 400 °C and 500 °C. The addition of cellulose or xylan significantly affected the transformation of nitrogenous compounds in tars, while lignin exhibited a relatively weaker influence on this process.
研究领域:
能源与燃料
·
化学工程
·
生物质转化
✓ 已验证
产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2025
·
IF 9
Yang Peng,Xianqing Zhu,Qian Shen,Yun Huang,Ao Xia,Jingmiao Zhang,Xun Zhu,Qiang Liao
Co-hydrothermal carbonization (co-HTC) of microalgae and lignocellulosic biomass can boost co-hydrochar yield and nitrogen retention rate, but the co-hydrochar still suffers from low nitrogen content and porosity. Accordingly, in this study, FeCl 3 , NH 4 Cl and melamine were employed as additives to intensify the co-HTC process of microalgae (CP) and corn stalk (CS), and their impacts on the co-hydrochar yield, physicochemical properties and nitrogen transformation pathways were firstly investigated comprehensively. The results indicated that adding FeCl 3 increased co-hydrochar’s specific surface area, but the oxidation power of Fe 3+ facilitated nitrogen into the aqueous-phase products, leading to the nitrogen distribution in aqueous-phase products reaching up to 83.51 %. Melamine incorporation increased the nitrogen content of co-hydrochar (6.95 %) and oil-phase products, while reduced co-hydrochar’s porosity. NH 4 Cl was the most effective additive for nitrogen-doped hydrochar production, simultaneously increasing the yield (40.24 %), nitrogen content (8.93 %) and specific surface area (9.12 m 2 g −1 ) of co-hydrochar. The nitrogen transformation mechanism during NH 4 Cl-assisted co-HTC process could be divided into two stages. At the first stage (200 ℃–240 ℃), the NH 4 + in NH 4 Cl could react with hydrolysis intermediates (Maillard and Mannich reactions) to generate heterocyclic nitrogen compounds entering the oil-phase, which would further react with the oxygen-containing functional groups to facilitate the nitrogen enrichment in the co-hydrochar. At the second stage (240 ℃–280 ℃), a portion of hydrochar would undergo secondary degradation and formed water-soluble nitrogen-rich small molecules, which were transferred to the aqueous-phase products again. This study demonstrated the high feasibility of additive-assisted co-HTC for producing high-quality nitrogen-rich carbon materials.
研究领域:
环境科学
·
生物质能
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Energies
·
2022
·Vol. 15
·期 19
·7221
·
IF 3.252
Mengyao Guo,Shu Yu,Shu Zhang,Juntao Wei,Wenran Gao,Weina Bao,Lei Shi,Hong Zhang,Deliang Xu
In thermal conversion utilization, nitrogen-rich biomass such as waste wood-based panels will release a large amount of NOxinto the atmosphere, causing serious harm to the surroundings. By means of co-pyrolysis, N in waste wood-based panels can be fixed in chars instead of discharging into the atmosphere in the form of volatile matter, which can reduce NOxemission and lay a foundation for the preparation of nitrogen-rich carbon materials with high added value. As the most commonly used adhesive in the production of wood-based panels, urea-formaldehyde resin adhesive (UF) is the main nitrogen source in waste wood-based panels. Therefore, the purpose of this paper is to explore the effects of glucose, ethyl maltol and 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DMHF) on nitrogen migration and conversion during UF pyrolysis by adjusting the different proportions of model compounds and UF. Thermogravimetric analysis showed that ethyl maltol and DMHF had lower thermal stability and the pyrolysis process was concentrated in the range of 90–168 °C, which does not coincide with the mass loss temperature of UF. UF can promote the pyrolysis of these three model compounds at the initial stage to some extent. The elemental analysis showed that the N retention in co-pyrolysis chars increased in varying degrees with the increase of the addition of model compounds; the nitrogen retention in chars of glucose-UF, ethyl maltol-UF and DMHF-UF increased by 28.47%, 3.48% and 16.45% with the increase of the model compound content from 50% to 90%, respectively. The XPS results showed that the relative content of N-6 in chars increased with the increase of ethyl maltol content, and the relative content of N-5 in chars increased with the increased addition of DMHF. Glucose had little effect on the distribution of N-functional groups in chars.Keywords:wood;thermal conversion;model compounds;urea-formaldehyde resin adhesive;char;nitrogen migration and transformation
研究领域:
能源科学
·
生物质能
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Mian Hu,Meiqi Chen,Zhibin Li,Zhiheng Ye,Zhong-Ting Hu,Zhiyan Pan,Dabin Guo,François Nkinahamira,Jinling Wan,Libo Wu,Baihui Cui,Junliang Wang
Catalytic subcritical water oxidation (CSWO) of M−nitroaniline (M−NA) was investigated in a fused quartz tube reactor (FQTR) to determine the effects of reaction parameters on M−NA mineralization rate, total nitrogen (TN) removal rate and nitrogen-containing products distribution. The results indicated that the TN removal rate was only 26.36 % at 200 °C, 200 % excess oxidant and 15 min residence time, while the TN removal rate reached 67.83 % at 360 °C in SWO of M−NA. Compared with SWO of M−NA, the mineralization rate and TN removal rate of CSWO of M−NA increased by about 10 % and 17.83 %, respectively. The main reason is mainly attributed to CuCo 2 O 4 catalyzing the preferential reaction of ·NO 2 with ·NH 4 , hastening N 2 generation. Alternatively, the CuCo 2 O 4 catalyst may induce a direct reaction between the nitro and amino groups on M−NA within the benzene ring to form N 2 . Moreover, degradation pathways and nitrogen migration mechanism of M−NA under SWO/CSWO conditions were proposed. These crucial findings are expected to guide the development of environmentally sustainable catalytic technologies towards addressing significant water pollution challenges.
研究领域:
环境科学
·
催化化学
✓ 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）