大柳塔长焰煤中灰分和无机矿物对生物产气的影响

Effect of ash and inorganic minerals in Dalita long-flame coal on biogas production

摘要:

[目的] 以不同密度等级大柳塔长焰煤作为产气底物，前期驯化培养厌氧菌群进行生物模拟产气实验，研究不同密度等级煤中的灰分和无机矿物对生物产气的影响。[方法] 利用小浮沉将大柳塔长焰煤分成不同密度等级的煤样，采用工业分析、XRD、XRF分析小浮沉处理得到煤样的理化性质，利用这些煤样进行生物产气模拟实验，以甲烷产量作为评价指标，分析不同密度等级煤样中灰分对产气的影响。最后，通过添加几种标准矿物方式比较了煤中无机矿物对生物产气的可能影响。[结果] 不同密度等级煤样中灰分对产气量存在一般显著影响（P=0.035），且灰分与甲烷含量呈负相关关系，其灰分中的无机矿物如高岭土、菱铁矿、氧化亚铁镁等的积累对产气有抑制作用。不同矿物配比产气实验证实低含量的粘土矿物促进甲烷的生成，高含量的粘土矿物抑制产气。[结论] 不同密度等级煤中的灰分对生物产气存在一般显著的影响，高灰分煤的产气量低，而低灰分煤的产气量高。

关键词:生物煤层气;低阶煤;灰分;无机矿物;甲烷

Abstract:

[Objective] This study focuses on investigating the effects of ash content and minerals in long-flame coal from Daliuta with different density biogas production by simulated gas production experiments with enriched cultures of anaerobic bacteria and archaea. [Methods] Daliuta long-flame coal was separated into different fractions by density with small floating sedimentation. The physiochemical properties of the coal fractions, including proximate analysis, XRD, and XRF were analyzed. These coal fractions were used to conduct biogas production experiments. The methane yield was used as an indicator to evaluate the effect of ash content on gas production in different coal fractions. The effect of minerals in coal was also investigated by amendments of commercial-grade minerals. [Results] It appears that the effects of ash content in coal on gas production is significant (P=0.035). i.e., ash content is negatively correlated to the methane yield. Moreover, minerals such as kaolin, siderite, and ferrous magnesium oxide in the ash could suppress gas production. Experiments with different mineral ratios confirmed that gas production was prominent with low content of clay minerals and restricted with high content of clay minerals. [Conclusion] The ash content of coals of different density generally has a significant effect on biogas production. The methane yield was low for high-ash coal and high for low-ash coal.

Key words:biogenic coal bed methane;low rank coal;ash;inorganic minerals;methane