Research and application of liquid supply system with distributed energy accumulators in fully-mechanized mining face

To solve the problem of rapid following and advancing speed of support in the fully mechanized mining face, a distributed liquid supply system based on accumulators was proposed and tested in the S1204 working face in Ningtiaota Coal Mine. The speed of advancing support movement in the middle of working face was determined based on the coal mining process and capacity requirements, and a simulation model was established for the existing liquid supply system to simulate the advancing process of single, double, and triple supports, and the factors affecting the advancing time of supports were analyzed. The results showed that the following speed should reach 12 m/min to meet the capacity requirements which is 10 million tons per year of the working face. The double or triple support moving in groups was necessary to meet the requirements of advancing time. To solve the problem of large pressure fluctuations and easy support loss in this working condition, the distributed energy storage and pressure stabilization promoting scheme was proposed to balance the contradiction between insufficient instantaneous flow supply and excessive average flow supply capacity in the hydraulic system of the working face by installing “accumulator+check valve” on the hydraulic support. The design method of accumulators based on the flow compensation was also provided. The simulation results showed that after installing the accumulator, the advancing time for double and triple support movement in groups was reduced by 6.2% and 11.5% respectively. Especially after continuous interference, the advancing time for double support movement in groups could be reduce by 15%. The underground application results showed that after installing the distributed accumulators in the liquid supply system, the advancing speed of the supports was significantly improved, and the phenomenon of loss in group pulling was significantly reduced. It played an important supporting role in increasing the average daily footage of the working face from 16.7 to 19.8 cuts, with a normalized daily footage of 22 cuts, achieving an annual production capacity of 10 million tons. This study provides an effective solution method to achieve rapid movement of support in groups.