【作者】 张倩；

【导师】 何环；

【作者基本信息】 中国矿业大学 ， 生物化工， 2021， 硕士

【摘要】 我国拥有重要的生物成因煤层气藏,在寻求高效开发我国丰富储藏褐煤资源的背景下,利用微生物将褐煤转化为甲烷的手段受到越来越多研究人员的关注。然而,当前煤中无机矿物组分对生物成气的影响研究报道较少,其机理需要进一步研究。本文选择陕西大柳塔煤作为研究对象,以采自厌氧污泥的混合微生物作为出发菌群,首先通过煤炭的大浮沉方法得到不同密度等级的煤,并对煤的物化性质进行表征,通过生物产气试验分析不同密度等级的煤对生物产气的影响,筛选出可能存在影响的代表性矿物,进而研究几种代表性矿物对生物产气的影响机制。煤炭大浮沉实验将大柳塔煤制备成了1.3-1.4 g/cm³、1.4-1.5 g/cm³、1.5-1.6g/cm³、1.6-1.7 g/cm³、1.7-1.8 g/cm³等5个不同密度等级的煤样,并通过工业分析、XRD、XRF以及红外光谱等手段来表征5个密度级煤样的物化性质差异。结果表明:各密度级煤样中的灰分含量随着密度级的升高而增大,固定碳含量呈现低密度级煤样较高、高密度级煤样较低的特点,低密度级（1.3-1.4 g/cm³）、中密度级（1.5-1.6 g/cm³）、高密度级（1.7-1.8 g/cm³）煤样中均检测出了石英、方解石、高岭土三种矿物,随着煤样密度级的增加,煤中的方解石、黄铁矿、硅铝酸盐矿物的含量也增加。从低密度级到高密度级,代表烷烃C-H伸缩振动（2850、2919、2920、2966）、羟基-OH或者氨基-NH-（3430、3342）和醚C-O伸缩振动（1227、1267）的峰均消失,说明随着煤样密度级的升高,煤中相应的官能团也出现减少的趋势。不同密度等级煤样的生物产气试验表明煤中灰分、挥发分、固定碳含量均对产CH₄量有显著影响,其中,灰分和固定碳含量的影响极其显著（p<0.05）,煤中的Fe、Ti、K、Ca、Sr等5种元素的含量对产CH₄量具有显著影响。综合XRD分析结果说明煤中黄铁矿、方解石、高岭石的存在对生物甲烷的产生具有一定的影响。对于较低灰分组（1.3-1.4 g/cm³、1.4-1.5 g/cm³）和较高灰分组（1.6-1.7 g/cm³、1.7-1.8 g/cm³）两组中细菌和古菌进行多物种组间差异检验,门水平上细菌中的Desulfobacterota（脱硫细菌门）以及属水平上细菌中的Geobacter（地杆菌属）、Clostridium（梭菌属）、Smithella（属于变形菌门）以及Bacteroidetes＿vadin HA17（属于拟杆菌门）与古菌中的Methanofollis（甲烷泡菌属）等5个属在较低灰分组和较高灰分组中的分布具有一般显著的统计学差异（p<0.05）,这可能导致了不同灰分含量煤样组产气量的差异。研究不同质量分数的黄铁矿、高岭土、方解石对煤的生物产气过程中CH₄含量的动态变化、产气后发酵液中VFA浓度、辅酶F₄₂₀活性变化。结果表明:与对照组相比,整体上黄铁矿的添加促进了VFA的生成,增大了发酵液中辅酶F₄₂₀的活性,然而产气一段时间（29 d）后黄铁矿的添加会抑制厌氧环境中煤的生物产CH₄速率,这可能与产甲烷前体物质的生成受阻有关。高岭土添加量为2%时最有利于甲烷生成,高岭土的添加能增大发酵液中辅酶F₄₂₀的活性。方解石的添加会抑制VFA的生成,其辅酶F₄₂₀活性在各添加梯度组之间大致呈正态分布,而方解石添加量较少（0.5%,1%）或者较多（8%）辅酶F₄₂₀较低,最终产气结果显示方解石的添加对煤的生物产CH₄量具有促进作用。产气后煤中的醇、酚-OH、-NH-和-NH₂被脱除。三种矿物的添加对煤生物产气过程中细菌和古菌的物种多样性均有一定的影响。对于细菌而言,黄铁矿试验组产气体系中含量最多的三种菌门依次是Firmicutes（厚壁菌门）、Bacteroidota（拟杆菌门）和Campilobacterota（弯曲菌门）,而高岭土试验组和方解石试验组产气体系中含量最多的三种菌门则依次是Firmicutes（厚壁菌门）、Desulfobacterota（脱硫细菌门）、Bacteroidota（拟杆菌门）。属水平上,Proteiniphilum（嗜蛋白菌属）、Paraclostridium（梭菌属）在黄铁矿试验组和方解石试验组产气体系中含量均较为丰富,而Desulforhabdus（杆状脱硫菌属）在高岭土试验组和方解石试验组中菌群丰度占比较大。此外,在三种外加矿物试验组产气体系中,均检测到了丰度较大的Geobacter（地杆菌属）。因此,黄铁矿、高岭土、方解石3种矿物的添加对煤的生物产气过程中关键酶的活性、煤被微生物利用的程度以及产气体系中的微生物多样性均有一定的影响,这些作用共同决定着最终甲烷的产生。该论文有图33幅,表14个,参考文献95篇更多还原

【Abstract】 China has important biogenic coal-bed methane reservoirs.In the context of seeking to efficiently develop my country’s abundant lignite resources,the use of microorganisms to convert lignite into methane is getting more and more attention from researchers.However,there are few reports on the role of inorganic mineral components in coal in the process of coal biogas formation.This paper selects the long-flame coal from Daliuta,Shaanxi Province as the research object,and takes the mixed microorganisms collected from anaerobic sludge as the starting flora.First,the coal of different density levels is obtained by the method of large floatation and sinking of the coal,and the physical and chemical properties of the coal are characterized.Through the biological gas production test,the influence of coal of different density grades on biological gas production is analyzed,and representative minerals that may have an impact are screened out,and then the influence mechanism of several representative minerals on biological gas production is studied.In the coal ups and downs experiment,Daliu Tower long flame coal was prepared into 5 pieces,including 1.3-1.4 g/cm³,1.4-1.5 g/cm³,1.5-1.6 g/cm³,1.6-1.7 g/cm³,1.7-1.8 g/cm³,etc.Coal samples of different density levels are characterized by industrial analysis,XRD,XRF,and infrared spectroscopy to characterize the differences in physical and chemical properties of the five density coal samples.The results show that the ash content in coal samples of various density levels increases with the increase of the density level,and the fixed carbon content presents the characteristics of higher coal samples at low density levels and lower coal samples at high density levels,and low-density coal samples（1.3-1.4 g/cm³）,medium-density（1.5-1.6 g/cm³）,and high-density（1.7-1.8 g/cm³）coal samples have detected three minerals:quartz,calcite,and kaolin.As the density level increases,the content of calcite,pyrite,and aluminosilicate minerals in the coal also increases.From low-density level to high-density level,it represents the peak average of alkane C-H stretching vibration（2850,2919,2920,2966）,hydroxyl-OH or amino-NH-（3430,3342）and ether C-O stretching vibration（1227,1267）Disappeared,It shows that as the density level of coal samples increases,the corresponding functional groups in the coal also tend to decrease.The biological gas production test of coal samples of different density grades showed that the ash,volatile matter,and fixed carbon content in the coal have a significant impact on the cumulative methane production.Among them,the ash content and fixed carbon content have an extremely significant effect（p<0.05）.The content of five elements such as Fe,Ti,K,Ca,Sr,etc.has a significant impact on the cumulative methane production.Combined with XRD analysis,it can indirectly show that the presence of pyrite,calcite,and kaolinite has a significant effect on biomethane production.For the lower ash group（1.3-1.4 g/cm³,1.4-1.5 g/cm³）and the higher ash group（1.6-1.7 g/cm³,1.7-1.8 g/cm³）,the bacteria and archaea in the two groups are multi-species Differences between groups were tested,Desulfobacterota in bacteria at the phylum level and Geobacter,Clostridium,Smithella and norank＿f＿＿Bacteroidetes＿vadin HA17（belonging to pseudobacteria）in bacteria at the genus level The distribution of 5 genera in the lower ash group and the higher ash group,including Methanofollis in the phylum Bacillus and Archaea,has a generally significant statistical difference（p<0.05）,which may have caused the difference in gas production between groups.Six different mass fractions of pyrite,kaolin,and calcite were added to the coal biogas production system to determine the dynamic change of CH₄ content during the gas production process,the VFA concentration in the fermentation broth after gas production,and the activity of coenzyme F₄₂₀.As an evaluation index,to study the influence of the addition of different minerals on coal biogas production.The results show that the addition of pyrite in the anaerobic system promotes the production of VFA and increases the activity of coenzyme F₄₂₀ in the fermentation broth.However,the addition of pyrite in the anaerobic environment will inhibit the production of gas for a period of time（29 days）.The rate of coal bio-production of CH₄ may be related to the hindrance of the production of methanogenic precursors.The addition of kaolin at about 2%is most conducive to the process of gradual decomposition of coal by microorganisms.The addition of kaolin can increase the activity of coenzyme F₄₂₀ in the fermentation broth.The addition of calcite can inhibit the bio-utilization process of coal in an anaerobic environment,and its coenzyme F₄₂₀ activity is approximately normally distributed among the addition gradient groups.Less calcite addition（0.5%,1%）or more（8%）is not conducive to the production of coenzyme F₄₂₀.The final gas production results show that the addition of calcite can promote the biological CH₄production of coal.In the process of gas production,the alcohol or phenol-OH or-NH-,-NH₂ on the surface of the coal is cut off.The addition of the three minerals had certain effects on the species diversity of bacteria and archaea in the process of coal biogas production.As for bacteria,Firmicutes,Bacteroidota and Campilobacterota were the three phyla with the highest content in the gas production system of the pyrite test group.However,Firmicutes,Desulfobacterota and Bacteroidota have the highest content in the gas production system of the kaolin test group and the calcite test group.At the genus level,Proteiniphilum and Paraclostridium are relatively rich in the gas production system in the pyrite and calcite experimental groups,while Desulforhabdus is relatively rich in the kaolin and calcite experimental groups.In addition,Geobacters with high abundances have been detected in the gas production systems of three experimental groups of exogenous minerals.Therefore,the addition of pyrite,kaolin,and calcite has a certain effect on the activity of key enzymes in the process of coal biogas production and the degree of utilization of coal by microorganisms.These effects together determine the final methane production.The paper has 33 pictures,14 tables,and 95 references更多还原