Experimental and numerical investigation on the near flammability limits behavior of syngas/air mixtures: effect of H2/CO ratios and inert gas additions

IF 5.4 3区工程技术 Q2 ENERGY & FUELS

Thermal Science and Engineering Progress Pub Date : 2025-09-26 DOI:10.1016/j.tsep.2025.104155

Bin Su , Yunsong Tan , Ruolin Hao , Litao Liu , Shangyong Zhou , Zhenmin Luo , Tao Wang

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Abstract

To promote the safe application of syngas (H₂/CO), the flammability limit parameters of syngas under varying H₂/CO ratios, along with the effects of inert gases (N₂, CO₂) on these limits and the explosion triangle, are investigated. Additionally, the chemical kinetic behavior near the lower flammability limit (LFL) of syngas is analyzed. The findings reveal that increasing the H₂ proportion in syngas significantly lowers the LFL and elevates the explosion hazard level. The introduction of inert gases notably reduces the upper flammability limit (UFL) and the explosion hazard level of syngas. As the H₂ proportion increases, the syngas explosion triangle expands and shifts toward the lower left, thereby reducing the non-explosive region area. The chemical kinetics near the LFL of syngas demonstrates increasing the volume ratio of H₂ in syngas can accelerate the generation rate of key free radicals, promote the generation of O and OH free radicals more rapidly, but intensify the inhibition of the generation of H free radicals. Among these, the elementary reactions R1, R3, R4, R5, R15, and R32 are identified as the most critical factors affecting the likelihood of syngas explosion. Adding appropriate inhibitors targeting these key elementary reactions can, to a certain extent, suppress the explosion of syngas. These findings provide valuable references and a foundation for enhancing the safe utilization of syngas.

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合成气/空气混合物近可燃性极限行为的实验和数值研究：H2/CO比和惰性气体添加量的影响

为了促进合成气（H2/CO）的安全应用，研究了不同H2/CO比下合成气的可燃性极限参数，以及惰性气体（N2、CO2）对这些极限参数和爆炸三角的影响。此外，还分析了合成气在燃烧下限附近的化学动力学行为。结果表明，增加合成气中H2的比例，可显著降低LFL，提高爆炸危险等级。惰性气体的引入显著降低了合成气的可燃性上限（UFL）和爆炸危险等级。随着H2比例的增加，合成气爆炸三角形扩大并向左下方移动，从而减少了非爆炸区域面积。合成气LFL附近的化学动力学表明，增加合成气中H2的体积比可以加快关键自由基的生成速度，促进O和OH自由基的生成速度加快，但对H自由基生成的抑制作用增强。其中，元素反应R1、R3、R4、R5、R15、R32被认为是影响合成气爆炸可能性的最关键因素。针对这些关键元素反应加入适当的抑制剂，可以在一定程度上抑制合成气的爆炸。这些发现为提高合成气的安全利用提供了有价值的参考和基础。

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来源期刊

Thermal Science and Engineering Progress Chemical Engineering-Fluid Flow and Transfer Processes

CiteScore

7.20

自引率

10.40%

发文量

327

审稿时长

41 days

期刊介绍： Thermal Science and Engineering Progress (TSEP) publishes original, high-quality research articles that span activities ranging from fundamental scientific research and discussion of the more controversial thermodynamic theories, to developments in thermal engineering that are in many instances examples of the way scientists and engineers are addressing the challenges facing a growing population – smart cities and global warming – maximising thermodynamic efficiencies and minimising all heat losses. It is intended that these will be of current relevance and interest to industry, academia and other practitioners. It is evident that many specialised journals in thermal and, to some extent, in fluid disciplines tend to focus on topics that can be classified as fundamental in nature, or are ‘applied’ and near-market. Thermal Science and Engineering Progress will bridge the gap between these two areas, allowing authors to make an easy choice, should they or a journal editor feel that their papers are ‘out of scope’ when considering other journals. The range of topics covered by Thermal Science and Engineering Progress addresses the rapid rate of development being made in thermal transfer processes as they affect traditional fields, and important growth in the topical research areas of aerospace, thermal biological and medical systems, electronics and nano-technologies, renewable energy systems, food production (including agriculture), and the need to minimise man-made thermal impacts on climate change. Review articles on appropriate topics for TSEP are encouraged, although until TSEP is fully established, these will be limited in number. Before submitting such articles, please contact one of the Editors, or a member of the Editorial Advisory Board with an outline of your proposal and your expertise in the area of your review.