Method and system for mine air flow quality monitoring and alarming on basis of controllable circulating air

The invention relates to a method and a system for mine air flow quality monitoring and alarming on the basis of controllable circulating air. The system comprises a harmful component purifying unit, a purified air component sensor, an air door, a mixed air component sensor, an air door control unit, a monitoring and control computer and a ventilation network simulation computer. The method includes: the harmful component purifying unit purifies mine return air; the purified air component sensor and the mixed air component sensor detects harmful component concentration of purified return air and harmful component concentration of mixed air respectively; the air door control unit controls opening, closing and opening angles of the air door according to control signals of the monitoring and control computer so as to realize mixing of fresh air and purified return air according o a controllable proportion; the ventilation network simulation computer and the monitoring and control computer monitor harmful component concentration values to realize monitoring of operating states of the harmful component purifying unit and regulation of openness of the air door.