Study On Fire-fighting Performance Of New Gel For Preventing And Control Coal Spontaneous Combustion

Gel fire-fighting technology and materials have made great progress in the prevention and control of coal fire disasters such as coal spontaneous combustion and mine fires.Although many gel fire-fighting materials and technologies have emerged,however,in practical applications,there are still shortcomings and deficiencies such as high cost,poor fluidity,complex downhole injection equipment,and material contamination of the working surface.It is planned to research and develop a new type of gel that is A and B liquid at room temperature,which will form a gel with low viscosity,good fluidity,and gradually gel in a certain period of time after mixing,and has the characteristics of convenient use and good fire-fighting perform,ance.Based on gel theory research,three crosslinking agents and five gelling agents were selected for pairwise cross-compounding experiments,and evaluation and optimization were made according to the index parameters such as gelation time,gel-forming system properties,viscosity,and concentration.Determine the best component materials,concentration and ratio of the new gel,and verify it through orthogonal preparation experiments.Through infrared experiment,thermal stability experiment and temperature program experiment,reaserach the distribution of coal molecular groups,the effect of gel on coal molecular groups,the temperature resistance and water retention of the new gel material,as well as the gel’s inhibitory effect on the spontaneous combustion process of coal oxidation.The results show:the optimal component materials are cross-linking agent L1,gelling agent J2 and modified substance MGP,and the corresponding concentration and ratio are(L1+MGP-10%+3%):(J2-8%)=1:1;The changes in the concentration of the three component materials cause the correlation of changes in gel formation results,gelling agent J2 is the largest,crosslinking agent L1 is the second,and MGP is the smallest;The new gel has an inhibitory effect on coal molecular groups,and the inhibitory effect increases with the increase of the concentration of component A/B,and the inhibitory effect is more affected by the concentration of component B;The absorbance and peak area of the molecular groups of the coal sample treated with the best gel are greatly reduced,especially the hydroxyl group,carbon-oxygen single bond and carbonyl group which are closely related to the spontaneous combustion of coal.The descending order of the content of each group is as follows:carbonyl>carbon-oxygen single bond>aromatic hydrocarbon>hydroxyl>methyl>methylene>carbon-carbon double bond>hydrogen bond;The new gel material has good thermal stability,and the gel system can retain water for more than 6 hours;The addition of new gel materials can reduce the amount and rate of CO produced during the spontaneous combustion of coal.When 30g,60g and 90g gel are added,the inhibition rate of 1kg experimental coal sample can reach about 37%,54%and 65%respectively;The addition of new gel materials can increase the activation energy of the reaction,making it more difficult for coal-oxygen reactions to occur.