Journal of The Energy Institute最新文献_第4页

Catalytic hydrothermal liquefaction of Azolla filiculoides into hydrocarbon rich bio-oil over a nickel catalyst in supercritical ethanol 镍催化剂在超临界乙醇中催化丝兰水热液化成富含碳氢化合物的生物油

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-23 DOI: 10.1016/j.joei.2024.101826

Hydrothermal liquefaction (HTL) is one of the most promising thermochemical techniques for converting wet biomass into crude oil-like products (bio-oil). In this study, Catalytic hydrothermal liquefaction of Azolla filiculoides (AZ) was performed over a various loading of nickel (Ni) on magnesium oxide (MgO) catalyst for the higher and quality bio-oil production. The key operating parameters such as temperature, reaction holding time, amount of Ni on MgO supports catalyst, and reaction solvents were investigated in the presence of a hydrogen environment. There was a 12.8 wt% increase in bio-oil yield and a 6.3 wt% decrease in biochar yield with addition of 15 wt% Ni catalysts compared to the non-catalytic reaction bio-oil yield (44.0 wt%). Results confirmed the highest total bio-oil yield of 56.8 wt% was attained at 280 °C with the catalyst amount of 15 wt% at a residence time of 45 min. Gas chromatography-mass spectrometry (GC-MS), FT-IR, CHNS, TGA, and NMR analyses were performed on the bio-oil, identifying 32.8 % long-chain hydrocarbons (C₁₂-C₁₆) along with small amounts of alcohols, alkanes, and esters. The boiling point distribution revealed that bio-oil produced using the Ni/MgO catalyst contained a significantly higher proportion of diesel-range hydrocarbons (42.4 %). Furthermore, the bio-oil yield under ethanol solvent and Ni catalysts showed higher heating value (HHV) 42.2 MJ/kg. Overall in the presence of Ni hydrogenation efficient catalysts on MgO in the liquefaction reaction promoted the deoxygenation and hydrogenation reaction.

水热液化（HTL）是将湿生物质转化为类原油产品（生物油）的最有前途的热化学技术之一。在这项研究中，为了生产出更高质量的生物油，在氧化镁（MgO）催化剂上添加了不同含量的镍（Ni），对丝兰（AZ）进行了催化水热液化。在氢气环境下，对温度、反应保持时间、氧化镁载体催化剂上的镍含量和反应溶剂等关键操作参数进行了研究。与非催化反应生物油产量（44.0 wt%）相比，添加 15 wt% Ni 催化剂后，生物油产量增加了 12.8 wt%，生物炭产量减少了 6.3 wt%。结果证实，在 280 °C 温度下，催化剂用量为 15 wt%，停留时间为 45 分钟时，生物油总产量最高，达到 56.8 wt%。对生物油进行了气相色谱-质谱联用仪 (GC-MS)、傅立叶变换红外光谱 (FT-IR)、碳氢化合物分析仪 (CHNS)、热重分析仪 (TGA) 和核磁共振分析，确定了 32.8% 的长链碳氢化合物（C12-C16）以及少量的醇、烷和酯。沸点分布显示，使用 Ni/MgO 催化剂生产的生物油中柴油级碳氢化合物的比例明显更高（42.4%）。此外，在乙醇溶剂和镍催化剂作用下产生的生物油显示出更高的热值（HHV）42.2 MJ/kg。总之，在液化反应中，氧化镁上的镍加氢高效催化剂促进了脱氧和加氢反应。

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引用次数: 0

Fast co-pyrolysis characteristics of polyethylene terephthalate and epoxy resin from waste wind turbine blades 废弃风力涡轮机叶片中的聚对苯二甲酸乙二醇酯和环氧树脂的快速共热解特性

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-21 DOI: 10.1016/j.joei.2024.101841

The present study systematically investigated the fast co-pyrolysis characteristics of epoxy resin and polyethylene terephthalate (PET) derived from waste wind turbine blades, with the aim of uncovering the possible synergistic effect in co-pyrolysis. The co-pyrolysis of epoxy resin and PET was beneficial to the formation of pyrolytic char, while the generation of small molecule gaseous products was restrained to a certain degree. The kinetic results revealed that the presence of epoxy resin dramatically reduced the energy barrier for PET decomposition into terephthalic acid (TPA) and vinyl benzoate via a cyclic transition state, finally resulting in an obvious reduction in the activation energy of the pyrolysis reaction. Remarkably, the activation energy for co-pyrolysis sharply decreased to around 150 kJ/mol at a low conversion rate. The co-pyrolysis presented a significant impact on the further transformation of primary pyrolysis products via decarboxylation, deoxygenation, decarbonylation, isomerization, and so on, thus contributing to the selective production of specified chemicals. Furthermore, the plausible reaction pathways and synergistic mechanisms between co-pyrolysis of epoxy resin and PET were discussed thoroughly.

本研究系统研究了从废弃风力涡轮机叶片中提取的环氧树脂和聚对苯二甲酸乙二酯（PET）的快速共热解特性，旨在揭示共热解过程中可能存在的协同效应。环氧树脂和聚对苯二甲酸乙二醇酯的共热解有利于热解炭的形成，而小分子气态产物的生成则受到一定程度的抑制。动力学结果表明，环氧树脂的存在大大降低了 PET 通过循环过渡态分解成对苯二甲酸（TPA）和苯甲酸乙烯酯的能障，最终导致热解反应的活化能明显降低。值得注意的是，在低转化率条件下，共热解的活化能急剧下降至 150 kJ/mol 左右。共热解对初级热解产物通过脱羧、脱氧、脱羰基、异构化等进一步转化产生了重大影响，从而有助于选择性地生产特定化学品。此外，还深入讨论了环氧树脂和 PET 共同热解的合理反应途径和协同机制。

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引用次数: 0

Experimental evaluation of municipal solid waste air-gasification in a pilot-scale reciprocating moving-grate furnace 中试规模往复式移动炉排炉中城市固体废物空气气化的实验评估

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-20 DOI: 10.1016/j.joei.2024.101833

The increasing volume of municipal solid waste (MSW) worldwide presents significant environmental challenges, necessitating the development of efficient waste-to-energy (WtE) solutions. Among various thermochemical methods, gasification offers a promising approach for converting MSW into syngas, which can be utilized for energy generation. This study investigates the gasification characteristics of MSW in a pilot-scale reciprocating moving-grate furnace, focusing on the effect of key operating parameters such as equivalence ratio (ER), gasification temperature, and gasifying agent-staged ratio on gasification characteristics.

Seven experimental schemes were tested with varying lower heating values (LHV) of MSW (ranging from 6.98 to 15.1 MJ/kg) and throughputs (ranging from 0.77 to 1.67 tons per day) to assess the adaptability and stability of the moving-grate system under different conditions. The results indicate that an ER between 0.6 and 0.7, a gasification temperature of 760 °C, and a gasifying agent-staged ratio of 7:3 are optimal for achieving a maximum energy conversion efficiency of 71.6 %. It was observed that the LHV of syngas decreases when the gasification temperature exceeds 850 °C due to increased oxidation of light hydrocarbons. Moreover, the study highlights the influence of grate moving speed on residence time and reaction completeness, which are critical for optimizing syngas yield and quality.

The findings demonstrate that while the maximum energy conversion efficiency of the moving-grate system is lower than other reactor types, its lower capital and operating costs, due to the lack of dedicated feedstock pretreatment, make it a viable option for small-scale and pilot-scale applications. This study provides valuable insights into optimizing MSW gasification processes and underscores the potential of the moving-grate furnace for adaptable and cost-effective WtE applications. The novelty of this work lies in the comprehensive evaluation of the moving-grate gasification process under varied operating conditions, providing a foundation for future research on improving efficiency and reducing environmental impact in large-scale MSW management.

全球城市固体废物（MSW）数量的不断增加带来了巨大的环境挑战，因此有必要开发高效的废物变能源（WtE）解决方案。在各种热化学方法中，气化是将城市固体废物转化为合成气的一种有前途的方法，合成气可用于能源生产。本研究调查了 MSW 在中试规模往复式移动格栅炉中的气化特性，重点研究了等效比 (ER)、气化温度和气化剂阶段比等关键操作参数对气化特性的影响。在不同的 MSW 较低热值 (LHV) （从 6.98 到 15.1 MJ/kg）和吞吐量（从每天 0.77 到 1.67 吨）条件下测试了七种实验方案，以评估移动格栅系统在不同条件下的适应性和稳定性。结果表明，ER 值介于 0.6 和 0.7 之间、气化温度为 760 °C、气化剂分级比例为 7:3 是实现 71.6 % 最大能量转换效率的最佳条件。研究发现，当气化温度超过 850 ℃ 时，由于轻烃的氧化作用增加，合成气的 LHV 会降低。研究结果表明，虽然移动炉排系统的最大能量转换效率低于其他类型的反应器，但由于不需要专门的原料预处理，其资本和运营成本较低，因此是小规模和中试规模应用的可行选择。这项研究为优化 MSW 气化工艺提供了宝贵的见解，并强调了移动炉排炉在适应性强、成本效益高的 WtE 应用方面的潜力。这项工作的新颖之处在于在不同操作条件下对移动炉排气化过程进行了全面评估，为今后在大规模 MSW 管理中提高效率和减少环境影响的研究奠定了基础。

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引用次数: 0

Catalytic pyrolysis of wheat straw based on dual catalyst CaO/ZSM-5 with acid washing and torrefaction pretreatment to enhance aromatic yield in bio-oils 基于 CaO/ZSM-5 双催化剂的小麦秸秆催化热解与酸洗和预处理以提高生物油中的芳烃产量

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101836

In this paper, the catalytic pyrolysis integrating combined pretreatment (acid washing and torrefaction) and dual catalysts was adopted to improve the quality of bio-oil and the selectivity of aromatic hydrocarbons. Combined pretreatment is a highly effective method to improve the quality of biomass feedstock. It was capable of the removal of alkali and alkaline earth metals from wheat straw, with a K removal rate of 97.79 %. Under the combined pretreatment, the aromatic hydrocarbon content in bio-oil increased to 68.8 % using the ZSM-5 catalyst alone. Compared with ZSM-5, CaO could remove part of the oxygenated functional groups and had a better acid removal effect, but the aromatic hydrocarbon yield was low to 7.95 %. After combined pretreatment using simulated aqueous phase bio-oil for acid washing, catalytic pyrolysis using CaO/ZSM-5 dual catalysts greatly enhanced the quality of the bio-oil. The oxygenated compounds content was reduced to 17.58 %, and the total hydrocarbon yield was increased to 82.42 %, especially the aromatic hydrocarbons yield was increased to 79.91 %, of which the monocyclic aromatic hydrocarbons were as high as 68.38 %, and the benzene, toluene, and xylene content reaching 49.39 %. Thus, integrating dual catalysts (CaO/ZSM-5) with combined pretreatment can effectively increase the aromatic yield for producing high-quality bio-oil.

本文采用联合预处理（酸洗和高温分解）和双催化剂的催化热解方法来提高生物油的质量和芳香烃的选择性。联合预处理是提高生物质原料质量的一种高效方法。它能够去除小麦秸秆中的碱金属和碱土金属，钾的去除率为 97.79%。在联合预处理中，单独使用 ZSM-5 催化剂，生物油中的芳香烃含量增加到 68.8%。与 ZSM-5 相比，CaO 可以去除部分含氧官能团，脱酸效果更好，但芳烃产率较低，仅为 7.95%。在使用模拟水相生物油进行酸洗的联合预处理后，使用 CaO/ZSM-5 双催化剂进行催化热解可大大提高生物油的质量。含氧化合物含量降低到 17.58%，总烃收率提高到 82.42%，尤其是芳香烃收率提高到 79.91%，其中单环芳香烃高达 68.38%，苯、甲苯和二甲苯含量达到 49.39%。因此，将双催化剂（CaO/ZSM-5）与联合预处理相结合，可有效提高生产优质生物油的芳烃产率。

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引用次数: 0

The impact of transition metals (Cr, Mn, and Co) on the performance of the 10%Ni/Al2O3-10%CeO2 catalysts in combined CO2 reforming and partial oxidation of methane 过渡金属（铬、锰和钴）对 10%Ni/Al2O3-10%CeO2 催化剂在二氧化碳重整和甲烷部分氧化联合反应中性能的影响

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101834

This study explores the efficacy of Cr, Mn, and Co promoters in enhancing the performance of 10%Ni/Al₂O₃-10%CeO₂ catalysts during methane combined reforming process, emphasizing improved metal dispersion and reduced carbon formation. The supports and catalysts were synthesized through mechanochemical and impregnation methods, respectively, and characterized using XRD, BET, TPR, TPO, and FESEM analyses. The synthesized catalysts exhibited a high BET surface area, ranging from 195 to 172 m² g^-1, along with a mesoporous structure characterized by pore sizes between 2 and 12 nm. The introduction of Cr significantly enhanced catalyst performance, resulting in 70.5 % CH₄ and 69.1 % CO₂ conversions in dry reforming. TPO analysis indicated reduced carbon deposition on promoted catalysts by enhancing Ni dispersion and carbon reactivity. The 10%Ni–3%Cr/Al₂O₃-10%CeO₂ catalyst demonstrated stability over 440 min at 700 °C, achieving 84.9 % CH₄ and 68.1 % CO₂ conversions in combined reforming. The TPO analysis indicated an absence of carbon deposition on the catalyst surface during combined reforming, which was corroborated by the FESEM analysis. Furthermore, the influence of operating parameters on catalyst efficiency in both dry and combined reforming processes was investigated. As GHSV increased from 8000 to 24,000 ml/h.gcat, CH₄ conversion declined in dry reforming and combined reforming, dropping from 77 % to 66 % and from 86 % to 84 %, respectively. Also, in both processes, increasing the oxidizer contents (CH₄: CO₂ from 2:1 to 1:2, CH₄: CO₂: O₂ from 1:1:0 to 1:1:0.35) led to an increase in CH₄ conversion, while CO₂ conversion decreased.

本研究探讨了铬、锰和钴促进剂在甲烷联合重整过程中提高 10%Ni/Al2O3-10%CeO2 催化剂性能的功效，重点是改善金属分散和减少碳的形成。分别通过机械化学法和浸渍法合成了载体和催化剂，并使用 XRD、BET、TPR、TPO 和 FESEM 分析对其进行了表征。合成的催化剂具有较高的 BET 表面积，范围在 195 到 172 m2 g-1 之间，并具有介孔结构，孔径在 2 到 12 nm 之间。铬的引入大大提高了催化剂的性能，在干转化过程中，CH4 和 CO2 的转化率分别达到 70.5% 和 69.1%。TPO 分析表明，通过提高镍的分散性和碳的反应性，减少了碳在促进催化剂上的沉积。10%Ni-3%Cr/Al2O3-10%CeO2 催化剂在 700 °C 下稳定运行 440 分钟，在联合转化过程中实现了 84.9% 的 CH4 转化率和 68.1% 的 CO2 转化率。TPO 分析表明，在联合转化过程中催化剂表面没有碳沉积，FESEM 分析也证实了这一点。此外，还研究了干法转化和联合转化过程中操作参数对催化剂效率的影响。随着 GHSV 从 8000 ml/h.gcat 增加到 24000 ml/h.gcat，干转化和联合转化过程中的 CH4 转化率均有所下降，分别从 77% 降至 66%，从 86% 降至 84%。此外，在这两种工艺中，提高氧化剂含量（CH4：CO2 从 2:1 提高到 1:2，CH4：CO2：O2 从 1:1:0 提高到 1:1:0.35）可提高 CH4 转化率，而降低 CO2 转化率。

{"title":"The impact of transition metals (Cr, Mn, and Co) on the performance of the 10%Ni/Al2O3-10%CeO2 catalysts in combined CO2 reforming and partial oxidation of methane","authors":"","doi":"10.1016/j.joei.2024.101834","DOIUrl":"10.1016/j.joei.2024.101834","url":null,"abstract":"<div><div>This study explores the efficacy of Cr, Mn, and Co promoters in enhancing the performance of 10%Ni/Al<sub>2</sub>O<sub>3</sub>-10%CeO<sub>2</sub> catalysts during methane combined reforming process, emphasizing improved metal dispersion and reduced carbon formation. The supports and catalysts were synthesized through mechanochemical and impregnation methods, respectively, and characterized using XRD, BET, TPR, TPO, and FESEM analyses. The synthesized catalysts exhibited a high BET surface area, ranging from 195 to 172 m<sup>2</sup> g<sup>-1</sup>, along with a mesoporous structure characterized by pore sizes between 2 and 12 nm. The introduction of Cr significantly enhanced catalyst performance, resulting in 70.5 % CH<sub>4</sub> and 69.1 % CO<sub>2</sub> conversions in dry reforming. TPO analysis indicated reduced carbon deposition on promoted catalysts by enhancing Ni dispersion and carbon reactivity. The 10%Ni–3%Cr/Al<sub>2</sub>O<sub>3</sub>-10%CeO<sub>2</sub> catalyst demonstrated stability over 440 min at 700 °C, achieving 84.9 % CH<sub>4</sub> and 68.1 % CO<sub>2</sub> conversions in combined reforming. The TPO analysis indicated an absence of carbon deposition on the catalyst surface during combined reforming, which was corroborated by the FESEM analysis. Furthermore, the influence of operating parameters on catalyst efficiency in both dry and combined reforming processes was investigated. As GHSV increased from 8000 to 24,000 ml/h.gcat, CH<sub>4</sub> conversion declined in dry reforming and combined reforming, dropping from 77 % to 66 % and from 86 % to 84 %, respectively. Also, in both processes, increasing the oxidizer contents (CH<sub>4</sub>: CO<sub>2</sub> from 2:1 to 1:2, CH<sub>4</sub>: CO<sub>2</sub>: O<sub>2</sub> from 1:1:0 to 1:1:0.35) led to an increase in CH<sub>4</sub> conversion, while CO<sub>2</sub> conversion decreased.</div></div>","PeriodicalId":17287,"journal":{"name":"Journal of The Energy Institute","volume":null,"pages":null},"PeriodicalIF":5.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental study on the effects of co-firing mode and air staging on the ultra-low load combustion assisted by water electrolysis gas (HHO) in a pulverized coal furnace 煤粉炉中水电解气（HHO）辅助超低负荷燃烧的共燃模式和空气分级影响试验研究

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101828

Developing zero-carbon fuel (H₂/NH₃) co-firing technology with pulverized coal can improve the low-load flame instability and pollutant emissions of boilers during peak shaving. In this study, we propose to assist the low-load combustion of coal powder furnaces with the safer water electrolysis gas (HHO). To further optimize the combustion strategy, a one-dimensional furnace combustion system coupled with an HHO gas generation and transportation system was used to investigate the effects of injection methods and air staging on the flue gas emission and auxiliary combustion characteristics of the lignite load reduction process and ultra-low load. The results indicate that reducing the coal combustion load achieves carbon reduction and reduces actual CO₂ emissions. The excess air coefficient increases, resulting in higher NO_X and lower CO emissions. Air staging can control NO_X and CO emissions during load shedding, with a 40.49 % reduction in NOX at 30 % load. Under ultra-low load, HHO-assisted combustion increases the oxygen concentration in the furnace, increasing NO_X emissions, while SO₂ decreases and then increases. However, the effect of HHO gas premixed mode (PM) on NO_X generation is weaker than that of staged mode (SM). As the flow rate of HHO increases, HHO-SM promotes the conversion of CO to CO₂ and reduces CO emissions, while CO emissions under PM remain at ∼10 ppm. Both HHO injection methods exhibit assisted combustion effects for ultra-low load operation. Due to the different effects of the two on the recirculation zone inside the combustion, the auxiliary combustion effect of PM is superior than that of SM. At 1800L/h HHO, the decrease in combustion instability coefficient (

β_{T}

) of PM is 57.14 %, higher than that of SM. Air staging is beneficial for stable combustion under ultra-low load, but it can affect the auxiliary combustion of HHO gas. Under ultra-low load HHO co-firing conditions, 11%-OFA can also control NO_X and CO emissions.

开发煤粉与零碳燃料（H2/NH3）共燃技术可改善锅炉在调峰期间的低负荷火焰不稳定性和污染物排放。在本研究中，我们建议使用更安全的水电解气体（HHO）来辅助煤粉炉的低负荷燃烧。为了进一步优化燃烧策略，我们利用一个与 HHO 气体生成和输送系统耦合的一维炉膛燃烧系统，研究了喷射方法和空气分段对褐煤减负荷过程和超低负荷时烟气排放和辅助燃烧特性的影响。结果表明，降低燃煤负荷可实现减碳，减少二氧化碳的实际排放量。过量空气系数增加，导致 NOX 增加，CO 排放减少。空气分级可控制减载过程中的 NOX 和 CO 排放，在 30% 负载时，NOX 可减少 40.49%。在超低负荷下，HHO 辅助燃烧增加了炉内氧气浓度，从而增加了 NOX 排放，而 SO2 则先减少后增加。然而，HHO 气体预混模式（PM）对 NOX 生成的影响弱于分段模式（SM）。随着 HHO 流量的增加，HHO-SM 会促进 CO 向 CO2 的转化并减少 CO 的排放，而 PM 下的 CO 排放则保持在 10 ppm 左右。两种 HHO 喷射方法在超低负荷运行时都表现出助燃效果。由于两者对燃烧内部再循环区的影响不同，PM 的辅助燃烧效果优于 SM。在 1800L/h HHO 条件下，PM 的燃烧不稳定系数（βT）下降率为 57.14%，高于 SM。空气分级有利于超低负荷下的稳定燃烧，但会影响 HHO 气体的辅助燃烧。在超低负荷 HHO 辅助燃烧条件下，11%-OFA 也能控制 NOX 和 CO 的排放。

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引用次数: 0

Study on fuel-N conversion mechanism of ammonia-coal co-firing at different combustion stages 不同燃烧阶段氨煤共烧的燃料-氮转化机理研究

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101829

The co-combustion of ammonia and pulverized coal can effectively reduce the carbon emission of thermal power generation. However, ammonia, as a carbon-free fuel, is rich in large amounts of nitrogen, which increases the risk of high NOx emissions. Therefore, it is important to clarify the influence mechanism of ammonia on the NO formation of coal volatile-N and coal char-N in the co-combustion, and to reveal the N oxidation pathway in different combustion stages.

In this study, simulations were carried out on the CHEMKIN software to investigate the generation characteristics of NO and the transformation mechanism of fuel-N at different combustion stages of ammonia-coal co-firing. The study showed that ammonia-blending combustion promoted the release of coal volatiles and the oxidation to NO. In the total NO generation during the ammonia-coal co-firing, the proportion of NO produced by ammonia-coupled coal char combustion was very low. Compared with ammonia-coupled coal combustion, the amount of NO produced in ammonia-coupled coal volatile combustion was significantly reduced. Sensitivity analysis and rate of production (ROP) analysis indicated that the increase of H, OH, and O free radicals promoted the NO formation, and that NH_i free radicals played an important role in the NO reduction. By analyzing the elementary path of NO generated from ammonia-coupled pulverized coal, coal volatiles and coal char combustion at 1400 °C and 10 % ammonia ratio, it can be seen that the main path of NO formation during ammonia-coupled coal volatiles combustion is VOL→HCN→NCO→NO, CHAR→NO, NH₂→HNO→NO, compared with ammonia-coupled coal combustion. The proportion of NH₂→NH→NO reaction paths decreased, while the proportion of NH₂→N₂, NCN→NCO→N₂, and NH₂→NNH→N₂ reaction paths increased respectively, indicating that separation combustion promoted the reduction of NO by NH_i free radicals while inhibiting the oxidation of N-containing components.

氨与煤粉共燃可有效减少火力发电的碳排放。然而，氨作为一种无碳燃料，富含大量的氮，增加了高氮氧化物排放的风险。因此，弄清氨在共燃过程中对煤挥发份-N 和煤炭-N 形成 NO 的影响机理，揭示不同燃烧阶段 N 的氧化途径具有重要意义。本研究利用 CHEMKIN 软件进行模拟，研究了氨煤共燃不同燃烧阶段 NO 的生成特征和燃料-N 的转化机理。研究表明，掺氨燃烧促进了煤挥发物的释放和氧化成 NO。在氨煤共烧过程中产生的 NO 总量中，氨耦合煤炭燃烧产生的 NO 所占比例很低。与氨耦合煤燃烧相比，氨耦合煤挥发燃烧产生的 NO 量明显减少。灵敏度分析和生成率（ROP）分析表明，H、OH 和 O 自由基的增加促进了 NO 的形成，而 NHi 自由基在 NO 的还原过程中发挥了重要作用。通过分析氨耦合煤粉、煤挥发物和煤焦在 1400 ℃、10%氨比条件下燃烧产生 NO 的基本路径，可以看出，与氨耦合煤燃烧相比，氨耦合煤挥发物燃烧过程中 NO 形成的主要路径是 VOL→HCN→NCO→NO、CHAR→NO、NH2→HNO→NO。NH2→NH→NO反应路径的比例下降，而NH2→N2、NCN→NCO→N2和NH2→NNH→N2反应路径的比例分别上升，表明分离燃烧促进了NHi自由基对NO的还原，同时抑制了含N成分的氧化。

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引用次数: 0

Experimental study of NO emission in coal-methanol co-combustion under air-staged condition 空气阶段条件下煤与甲醇共燃中 NO 排放的实验研究

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101835

Application of renewable methanol as an alternative fuel is a promising method for both CO₂ and NO emission reduction in thermal power plants fueled by coal. This work gives the first insight into coal-methanol co-combustion from the perspective of NO emission control with a wide range of methanol blending ratio (0%–100 %) involved. Air-staged strategy commonly applied in thermal power plants fueled by coal was considered, and the effects of some key parameters, including burnout air ratio, burnout air injection position and furnace temperature, were analyzed. Experimental results show a significant potential of NO emission reduction in coal-methanol co-combustion, as NO emission from methanol combustion is less than 30 % of that from coal combustion. The correlation between NO emission and methanol blending ratio is approximately linear. Air-staged strategy is still effective for NO emission reduction in coal-methanol co-combustion, and the effects of the key parameter is similar to that in coal combustion. Increase of burnout air ratio and delay of burnout air injection are beneficial, and NO emission can be reduced by more than 70 % compared with that under unstaged condition. Furnace temperature rise is harmful, whereas the corresponding NO emission increase is lower than 30 ppm (@6 % O₂).

应用可再生甲醇作为替代燃料是以煤为燃料的火力发电厂减少二氧化碳和氮氧化物排放的一种可行方法。这项研究首次从氮氧化物排放控制的角度深入探讨了煤与甲醇的协同燃烧问题，其中涉及的甲醇掺混比例范围很广（0%-100%）。研究考虑了以煤为燃料的火力发电厂通常采用的空气分级策略，并分析了一些关键参数的影响，包括燃尽空气比、燃尽空气喷射位置和炉温。实验结果表明，煤-甲醇共燃具有显著的氮氧化物减排潜力，甲醇燃烧产生的氮氧化物排放量小于煤燃烧产生的氮氧化物排放量的 30%。NO 排放量与甲醇掺混率之间近似呈线性关系。在煤-甲醇联合燃烧中，空气分级策略对减少 NO 排放仍然有效，关键参数的影响与煤燃烧相似。增加燃尽空气比和延迟燃尽空气喷入是有益的，与未分阶段条件相比，氮氧化物排放量可减少 70% 以上。炉温升高是有害的，但相应的 NO 排放量增加低于 30 ppm（@6 % O2）。

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引用次数: 0

Comparison between the structural characteristics and process activity of bulk and mesoporous Ni-Co-Ce/Al2O3 catalysts in the dry reforming of methane 比较块状和介孔 Ni-Co-Ce/Al2O3 催化剂在甲烷干法转化中的结构特征和工艺活性

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101823

Dry reforming of methane (DRM) is a potential way to exploit greenhouse gases and generate hydrogen. Catalyst deactivation is the biggest DRM commercialization obstacle. Lately, Ni-Co bimetallic catalysts have demonstrated improved carbon resistance over Ni-based catalysts. The aim of this research is not just to investigate the impact of Ni-Co catalysts on the DRM activity, but also to evaluate the Ni-Co alloy creation effect on the catalyst characteristics and activity. Mesoporous alumina (MA) was used as a catalyst support for Ni-Co particles in this process and its structure and activity were compared to those of bulk alumina (BA) supported catalysts. In addition, cerium was included into all of the catalysts developed as a suitable promoter for reducing the amount of deposited coke. The results obtained from the XRD and nitrogen adsorption/desorption analysis indicated the formation of a mesoporous structure and nanocrystalline morphology in the Ni-Co/MA samples, as compared to the Ni-Co/BA ones. The results showed that the bimetallic 2Ni-1Co-1Ce/MA sample had the best catalytic activity, with a CH₄ conversion of 98.30 %, CO₂ conversion of 96.35 %, and H₂ yield of 96.30 % at 700 °C.

甲烷干重整（DRM）是一种利用温室气体并产生氢气的潜在方法。催化剂失活是 DRM 商业化的最大障碍。最近，Ni-Co 双金属催化剂比 Ni 基催化剂具有更好的抗碳性。本研究的目的不仅在于研究镍钴催化剂对 DRM 活性的影响，还在于评估镍钴合金的生成对催化剂特性和活性的影响。在此过程中，介孔氧化铝（MA）被用作 Ni-Co 颗粒的催化剂载体，其结构和活性与块状氧化铝（BA）载体催化剂的结构和活性进行了比较。此外，所有开发的催化剂中都加入了铈，作为减少沉积焦炭量的合适促进剂。XRD 和氮吸附/解吸分析结果表明，与 Ni-Co/BA 样品相比，Ni-Co/MA 样品形成了介孔结构和纳米晶形态。结果表明，双金属 2Ni-1Co-1Ce/MA 样品的催化活性最好，700 ℃ 时的 CH4 转化率为 98.30%，CO2 转化率为 96.35%，H2 产率为 96.30%。

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引用次数: 0

The effect of air distribution on the characteristics of waste combustion and NO generation in a grate incinerator 空气分布对炉排焚烧炉中垃圾燃烧特性和氮氧化物生成的影响

IF 5.6 2区工程技术 Q2 ENERGY & FUELS

Journal of The Energy Institute

Pub Date : 2024-09-19 DOI: 10.1016/j.joei.2024.101827

The combustion process optimization and nitrogen oxide emissions reduction of waste incineration power generation is a key challenge. In order to reveal the influence of air distribution on the combustion process and NO emission in a grate-type waste incinerator, the combustion process and NOx generation in a waste incinerator were studied, and the influence of different ratios of primary air in the grate chamber, different ratios of primary air and secondary air, and different speeds and angles of secondary air on the combustion and NOx emission characteristics were explored. The results show that the moisture evaporation and mass loss rates of combusted MSW (municipal solid waste) increase accordingly as the air ratios of the primary air in the zone1 increases. As the ratio of air flow in the combustion section (zone 2) in the grate chamber increases, the high temperature area and oxygen concentration above the grate will increase, and the NO formation will be promoted accordingly. The NO concentration at the furnace outlet is reduced from 259.34 mg/Nm³ to 201.34 mg/Nm³, as the air flow ratio of the grate chamber in the combustion section (zone 2) is reduced from 0.50 to 0.34. With the increase of secondary airflow ratio, the high temperature zone in the furnace increases, and more NO is generated above the grate, however, the NO concentration at the furnace outlet decreased, the probable reason is the combined result of temperature and turbulent kinetic energy. The secondary air speed has a great influence on NO generation. With the increase of secondary air speed of SA3 and SA4, the concentration of NO at the furnace outlet decreases. The secondary air angle has little effect on NO generation, but has great effect on temperature distribution uniformity.

垃圾焚烧发电的燃烧过程优化和氮氧化物减排是一项关键挑战。为了揭示空气分布对炉排式垃圾焚烧炉燃烧过程和氮氧化物排放的影响，研究了垃圾焚烧炉的燃烧过程和氮氧化物产生情况，探讨了炉排炉膛内一次风不同配比、一次风与二次风不同配比、二次风不同速度和角度对燃烧和氮氧化物排放特性的影响。结果表明，随着1区一次风比例的增加，燃烧后的MSW（城市固体废物）水分蒸发率和质量损失率也相应增加。随着炉排室燃烧段（2 区）空气流量比的增加，炉排上方的高温区和氧气浓度也会增加，相应地也会促进 NO 的形成。当燃烧段（2 区）炉排室的空气流速比从 0.50 降低到 0.34 时，炉膛出口处的 NO 浓度从 259.34 mg/Nm3 降低到 201.34 mg/Nm3。随着二次风流比的增大，炉内高温区增大，炉排上方产生更多的 NO，但炉出口处的 NO 浓度却降低了，这可能是温度和湍流动能共同作用的结果。二次风速对 NO 的生成有很大影响。随着 SA3 和 SA4 二次风速的增加，炉口的 NO 浓度降低。二次风角度对 NO 生成的影响不大，但对温度分布的均匀性有很大影响。

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引用次数: 0