Intelligent gas extraction and control strategy in coal mine

Precise gas drainage will be the way of gas control in the future. Currently,there are many problems in gas extraction,such as the unreasonable distribution of negative pressure,no timely regulation and control,high energy consumption and poor safety in underground gas drainage. Therefore,the principle of precise gas drainage is proposed based on the safety and efficiency principles. The flow governing equations of methane-air mixture gas in drainage sys-tem are established. A parameter optimization model for gas drainage pipe network is built with the maximum pure gas drainage flow rate as the objective function. According to this model,the safety and efficiency of gas drainage are quantitatively determined from the constraints of single parameters such as gas concentration,flow rate and efficiency ratio etc. On the basis of the model,theoretical analysis and numerical calculation are carried out under the working condi-tions of temperature in drainage area which is higher than the critical temperature,the pure flow rate of borehole drain-age which is lower than the prescribed minimum pure flow rate of gas drainage,and the gas concentration which is low-er than the prescribed minimum of safety gas concentration. Also,the corresponding optimization strategy of gas drain-age system under the characteristics of borehole gas drainage is put forward,which effectively increases the gas drain-age concentration,efficiency ratio and pure gas drainage amount. On this basis,an intelligent gas drainage system con-sisting of data-aware module,communication module,data processing and decision-making module and control module is designed to realize the connection of things with things and things with human. An intelligent regulating valve is de-veloped based on the Internet of Things (IoT). The data-aware module includes the sensors of temperature,gas con-centration and gas pressure,and the communication module uploads the data to the cloud storage,which provide the path to measure and control the system by PC web and mobile phone client. The technical method of improving the ef-ficiency of the water ring vacuum pump with high polymer drag reducer is proposed,which greatly reduces the turbu-lence loss of liquid ring and frictional loss. The two kinds of pump energy-saving system including surface closed type and underground direct injection type are proposed. The technology is successfully applied in Luan group of Shanxi province,which achieves the power saving rate of 22. 5% and water saving rate of 66. 7% and provides a basic support for gas precise drainage