Liquid nitrogen direct injection and foaming intelligent filling system based on mine fire area characteristics and application method

An application method for a liquid nitrogen direct injection and foaming intelligent filling system based on mine fire area characteristics, wherein:

• the liquid nitrogen direct injection and foaming intelligent filling system based on mine fire area characteristics, comprises a liquid nitrogen storage tank, a liquid nitrogen direct injection system and a foaming system,
• wherein the liquid nitrogen storage tank communicates with a liquid nitrogen pressurizer through a main pipeline;
• a temperature controller is arranged on the main pipeline;
• the liquid nitrogen pressurizer is connected with the liquid nitrogen direct injection system and the foaming system, respectively;
• the liquid nitrogen direct injection system comprises a first branch pipeline, a first branch valve and a liquid nitrogen density sensor arranged on the first branch pipeline;
• the foaming system comprises a second branch pipeline;
• the second branch pipeline communicates with a liquid nitrogen inlet of a foam generator;
• a foam liquid inlet of the foam generator communicates with a foam liquid plunger pump through a fifth branch pipeline;
• the foam liquid plunger pump communicates with a clean water tank through a fourth branch pipeline;
• a foam liquid tank is arranged on the fourth branch pipeline;
• a foam outlet of the foam generator communicates with a sixth branch pipeline;
• a foam density sensor is arranged on the sixth branch pipeline;
• a third branch pipeline communicates with the fifth branch pipeline;
• the third branch pipeline also communicates with a slurry or an inhibitor solution pipeline;
• the liquid nitrogen pressurizer communicates with the first branch pipeline and the second branch pipeline, respectively;
• a first flow control valve is arranged on the first branch pipeline;
• a second flow control valve is arranged on the second branch pipeline;
• a third flow control valve is arranged on the fifth branch pipeline;
• the liquid nitrogen density sensor and the foam density sensor are respectively connected with a controller;
• the controller is connected with the first flow control valve, the second flow control valve and the third flow control valve, respectively;
• the foam generator comprises a housing and a hollow spiral tube arranged in the housing;
• a foam liquid outlet, helical blades and stirring blades are arranged on the hollow spiral tube;
• the liquid nitrogen inlet and the foam outlet of the foam generator are respectively arranged on both sides of the housing;
• an opening of the hollow spiral tube is the foam liquid inlet;
• the foam liquid inlet and the liquid nitrogen inlet are formed at an end of the housing;
• the stirring blades are arranged at another end of the housing;
• the first branch valve, a first thermometer, a first pressure gauge, the first flow control valve, a first metal hose, a first one-way valve, a first pressure stabilizing valve, a block valve and a release valve are sequentially arranged on the first branch pipeline in a direction from the liquid nitrogen pressurizer to the liquid nitrogen density sensor;
• a second branch valve, a second thermometer, a second pressure gauge, a second flow control valve, a second metal hose, a second pressure stabilizing valve and a second one-way valve are sequentially arranged on the second branch pipeline in a direction from the liquid nitrogen pressurizer to the foam generator;
• a third branch valve and a third one-way valve are arranged on the third branch pipeline;
• a fourth branch valve is arranged between the clean water tank and the foam liquid tank;
• the third flow control valve, a fourth one-way valve and a fifth one-way valve are sequentially arranged on the fifth branch pipeline in a direction from the foam liquid plunger pump to the foam generator;
• the third branch pipeline communicates with the fifth branch pipeline between the fourth one-way valve and the fifth one-way valve;
• and a sixth one-way valve is arranged between the foam density sensor and the foam generator;
• wherein, the method comprises the following steps:
• a. sequentially connecting the liquid nitrogen direct injection system and the foaming system, and inspecting whether an airtight connection exists;
• b. filling liquid nitrogen into a fire area through the liquid nitrogen direct injection system by:
• opening the first branch valve, closing the second branch valve, opening a liquid inlet/outlet master valve connected with the liquid nitrogen storage tank, adjusting the liquid nitrogen pressurizer, the temperature controller, the first flow control valve, the second flow control valve, the first pressure stabilizing valve, the second pressure stabilizing valve, observing the first thermometer, the second thermometer, the first pressure gauge and the second pressure gauge, and if a density of the liquid nitrogen conforms to a first set threshold, directly injecting the liquid nitrogen into a mine fire area;
• if the density of the liquid nitrogen does not conform to the first set threshold, injecting into a characteristic fire zone after regulating a flow of the liquid nitrogen through the first flow control valve, the second flow control valve and the third flow control valve;
• c. filling extinguishing material into the mine fire area through the foaming system by:
• closing the first branch valve, opening the liquid inlet/outlet master valve connected with the liquid nitrogen storage tank, the second branch valve and the fourth branch valve, adjusting the liquid nitrogen pressurizer, the first flow control valve, the second flow control valve, the first pressure stabilizing valve and the temperature controller, observing the first thermometer, the second thermometer, the first pressure gauge and the second pressure gauge, and if a density of generated liquid nitrogen foams conforms to a second set threshold, directly injecting the liquid nitrogen foams into the mine fire area through the foam generator;
• if a density of the liquid nitrogen foams does not conform to the second set threshold, injecting into the characteristic fire zone after regulating the first flow control valve, the second flow control valve and the third flow control valve to regulate the flow of the liquid nitrogen foams;
• closing the first branch valve, opening the liquid inlet/outlet master valve connected with the liquid nitrogen storage tank, the second branch valve, the third branch valve and the fourth branch valve, adjusting the liquid nitrogen pressurizer, the flow control valve, the pressure stabilizing valve and the temperature controller, observing the first thermometer, the second thermometer, the first pressure gauge and the second pressure gauge, and if a foam density conforms to a third set threshold, directly injecting three-phase foams, inorganic solidified foams and inhibited foams into the mine fire area through the foam generator;
• if the foam density does not conform to the third set threshold, injecting into the characteristic fire zone after regulating the foam liquid, the flow of the liquid nitrogen, a slurry or an inhibitor solution.