当氧气体积分数大于7%以后，煤粉再燃过程不再具有脱硝效果。
When oxygen volume fraction is larger than 7%, the coal reburning process is ineffective for NOx reduction.
摘要用氧气体积分数法划分低瓦斯采空区自燃“三带”是目前在工程实践中应用最为广泛，也是最有效的方法。
Abstract: the oxygen concentration method is the most effective and most commonly used method in dividing spontaneous combustion "three zone" in low-gas goaf in engineering practice at present.
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