The Research On The Evaluation Model And Optimization Of Simultaneous Exploitation Of Coal And Gas

Coal is the main disposable leading energy in our country,and gas is associated products of coal.With the increase of strengthening exploitation and mining depth,gas content increases gradually,and gas control becomes more and more difficult.So simultaneous exploitation of coal and gas is an inevitable path to mining deepen coal resource.Engineering application of simultaneous exploitation of coal and gas has been set up basically in our country,but effectiveness,scientific and pertinence basic theoretic system info which matched with simultaneous exploitation of coal and gas technology has not formed.Therefor,the thesis analyzed the interaction of mutual promotion and mutual restrain between coal mining and gas extraction which were two subsystems of simultaneous exploitation of coal and gas,and studied simultaneous exploitation of coal and gas control parameter index system,and revealed the control parameters how to effect simultaneous exploitation of coal and gas,and explored the evaluation model and optimization theory of simultaneous exploitation of coal and gas which base on the air coordination mechanism.The research results are great importance to set up the basic theoretical system of simultaneous exploitation of coal and gas.Based on fluid mechanics,experimental mechanics,statistics,system optimization and mining engineering theory,and through the methods of laboratory tests,theoretical analysis and numerical simulation,the effect regularity for coal pressure relief and permeability during the mining process was got by the experiment.In addition,by use of the above theory and method,the thesis analyzed the interaction between coal mining and gas extraction,studied the evaluation index system of simultaneous exploitation of coal and gas and proposed index quantitative criteria.With help of mathematics methods,the thesis evaluated the coordination of simultaneous exploitation of coal and gas and analyzed the interaction of mutual acceleration and mutual forbearance between the coal mining and gas extraction.And the simultaneous exploitation of coal and gas collaborative optimization model was set up.Finally,combined with the optimization results,the extraction parameters have been optimized.(1)Through similar simulation experiment of simultaneous exploitation of coal and gas,protected coal seam permeability changes with stress variation in the process of protective coal seam working face driving.With stress changes from decreasing to increasing,protected coal seam permeability showed the change low of first increase after decrease.And fracture expansion had increase,activity and slowdown three stages.The thesis concluded that mining disturbance is key factor of gas flow.During the mining process,mining pressure relief improved gas extraction,and gas extraction provide security for coal mining.But with increasing of advancing rate of coal mining face,gas emission increased,and ventilation air methane concentration exceeds ultimate value.So advancing rate of coal mining face should be reduced.As a result,the relationship between coal mining system and gas extraction system is mutual promotion and mutual restriction.(2)On the basis of experimental study and on-site survey,simultaneous exploitation of coal and gas achieved the maximization of economic benefits and resource recovery rate by adjusting optimizing output and time of two subsystems.Time connection and processes planning of two subsystems established microscopical ordered structure and formed space-time coordination mechanism of simultaneous exploitation of coal and gas.(3)Using the methods of mathematical statistics,fuzzy mathematics and AHP,coal mining and gas extraction influencing factor was analyzed.And simultaneous exploitation of coal and gas evaluation control parameter was identified.The thesis considered the feasibility evaluation,safety evaluation and effect evaluation of simultaneous exploitation of coal and gas to build simultaneous exploitation of coal and gas control parameter index system.Furthermore,index has been divided into many grades.And the thesis decided the weight of every index by using AHP and fuzzy mathematics,and proposed the coordination as the simultaneous exploitation of coal and gas cooperativity indicators quantitative standards.In the end,evaluation system of simultaneous exploitation of coal and gas was got.(4)Considering the system optimization theory,synergy mechanism between coal mining and gas extraction was made.Taking the interaction relationship between coal mining system and gas extracting system as constraint equations,and taking economic efficiency maximization,coal resource recovery rate maximization and gas resources recovery rate maximization as objective function,and taking mining volume,mining time,gas extraction volume and extraction time as ventilation independent.The thesis established cooperative optimization theoretical model of simultaneous exploitation of coal and gas.And using MATLAB solved simultaneous exploitation of coal and gas optimization model.(5)According to collaborative optimization theory model of simultaneous exploitation of coal and gas,the thesis carried the coordination evaluation and optimization of Shaqu No.24207 working face.The evaluation results showed that it was primary coordination.In order to get the simultaneous exploitation of coal and gas optimal outputs and optimal time of this working face,it needs to be further optimized.Through further optimization,simultaneous exploitation of coal and gas profits increased by 14%,and gas drainage efficiency increased by 2.5%.Combined with optimization result,primary pre-drainage extraction parameters and drilling intervals were optimized by gas extraction mathematical model.The optimization results show that optimal gas extraction drilling intervals of No.24207 working face is 7m.