Research on intelligent fracturing pump system in coal mine

In order to solve the problem of insufficient core equipment support for safe and efficient mining technologies such as hard and stable roof treatment，gas drainage and permeability enhancement，a set of underground intelligent underground fracturing pump system was studied. The key technical problems such as large-flow pressure control technology for flow recovery，real-time adjustment of frequency conversion pressure during fracturing，and intelligent control and monitoring technologies were solved. The valve core hard sealing technology，reliable opening technology，transient large flow channel and cavity design，leakage recovery technology，pressure detection and pressure relief technology were integrated into the drainage recovery large flow pressure control technology. A large flow discharge recovery pressure control valve with a maximum flow of 1 000 L/min and a rated pressure of 40 MPa was developed to realize accurate pressure control and discharge recovery under large flow conditions. The real-time frequency conversion pressure regulation technology was on the basis of the pressure demand function of the fracturing process，including sealing，initiation and fracturing process. Based on the control closed-loop in terms of the controllers，sensors，frequency conversion pump stations and electronically controlled flow valves，the precise control of fracturing pressure in a large pressure range from 3 MPa to 40 MPa was realized. The intelligent control and monitoring technology has overcomeLMcore technical problems such as the low pressure automatic sealing，automatic pressure follow-up initiation，and automatic identification of fracturing. The key technology of underground ultra long hole composite fracturing was verified，and the industrial test of hydraulic fracturing treatment of hard rock roof was completed in Yulin Daliangwan Coal Mine，Mengcun Coal Mine of Shaanxi coal group and Shaqu No.1 Coal Mine of Huajin Group. Field test shows that the time of coal fracturing initiation is in the range of 4-15 minutes，the initiation pressure is in the range of 15-21 MPa，the pressure during fracturing is maintained at 12-16 MPa，and the amount of single injection is in the range of 1.3-5.5 m3. The application shows that the system can meet the requirements for the equipment used for the weakening and treatment of the ultra-long-distance hard and stable roof.