Two-step Optimization Method for Airflow Control Based on Mixed Integer Programming
Intelligent mining is an important direction for the future development of the mining industry.The construction of mine intelligent ventilation system is a key part of promoting the digital and intelligent development of mines.Under the current background of energy conservation and emission reduction,the ways of digital and information technology to achieve low-carbon mining,efficient utilization and intelligent control of non-ferrous metal resources,is the important technical guarantee to achieve the strategy of"carbon peaking and carbon neutrality".The key to realize the high-efficiency utilization of non-ferrous metal resources is to adopt the intelligent ventilation technology to reduce the energy consumption.In the current process of pro-moting the construction of intelligent mine ventilation system,a common hot and difficult issue is to realize the optimal regulation of airflow of mine ventilation system under the condition of ventilation on-demand.The ventilation optimization regulation of intelligent ventilation system requires that on the premise of satisfying the dynamic ventilation on-demand in different periods,the ventilation optimization theory based on fluid network was adopted to obtain a ventilation optimization regulation scheme that meets the requirements of safety,technology and economic.Then the airflow distribution and air pressure distribution of the ventilation network were adjusted to ensure the safe,reliable,stable and economic operation of the mine ventilation system.In order to solve the problem of difficulty in solving the optimization and regulation model of nonlinear mine ventilation network,based on the basic mathematical model of ventilation network airflow regulation,the method of airflow control and optimization of ventilation network was analyzed,and the objectives and constraints of the airflow regulation optimization model based on multi-objective mixed integer programming were analyzed.A two-step airflow control optimization mathematical model based on the mixed integer programming method by improving the two-step ventilation optimization method was proposed.The mathematical model is a multi-objective programming linear model with the goals of minimum ventilation energy consumption,minimum number of regulation equipment and optimal position of regulation equipment,so that the solution result of the mathematical model is more in line with the actual regulation needs.The mathematical model can constraint the number and regulating ways of regulation position by introducing the mixed integer programming method,and constraint the position of regulation schemes according to the actual situation of the mine by introducing the regulation level of branches,which improve the flexibility of ventilation regulation optimization schemes.In addition,by solving the corresponding regulation schemes of airflow distribution multiple times,the mathematical model can obtain a solution scheme that approximately satisfies the solution result of regulation mathematical model with unknown airflow,while avoiding the problem of non-convergence in solving nonlinear models.We construct a calculation example for the mine ventilation optimization regulation problem,and verify the reliability of ventilation regulation mathematical model based on the calculation of airflow distribution.