Study on the excitation and blocking system of trace elements in coals on the production of biogenic methane

In order to study influence on the production of biogenic methane from trace elements and their occurrence forms in coals,samples were taken from two coals A and B of similar degree of coalification,and the experiment of bio- logical gas production was carried out under the same condition of environmental and bacteria source to expore the effect mechanism of trace elements in the origin of fermentation substrate. The results showed that:① A coal gas pro- duction is 248 mL,26. 5% mineral gas volume more than B. The beneficial trace elements contents in A,such as Co, Ni,Zn,Mo,Mn,Fe,are much more than that of B. ② After biological gas production,trace elements in coal are re- duced to varying degrees;the amount of Fe,Mn,Cr in A and Fe,Mn,Mo in B decreased significantly,while the amount of Ni,Co,Zn in the two coals were reduced in different degrees. It shows that the trace elements in coal are involved in the reaction. ③ There are more humic acid combining state in raw coal with more gas production,and humic acid binding state is a form of methane producing bacteria. ④ Coal element occurrence before and after reaction indicated that humic acid bound and exchangeable element increased,molecules bound to organic matter content decreased,in- dicating that occurrence of the element changed. The content and occurrence state of trace elements in coal can provide a better reference for the mechanism of biological gas production.