1. Physical and chemical properties The main components of petroleum gas are propane, propylene, butane, butene, etc., which are easy to form explosive mixtures with air. LPG is stored and transported in liquid form by pressurization or cooling, which is liquefied petroleum gas. When liquefied petroleum gas changes from liquid to gaseous, the volume expands by 250-350 times; the relative density of air (air = 1) is 1.5-2 (heavier than air), and the relative density of liquid (water = 1) is 0.5 (lighter than water) ); it spreads slowly in the air and tends to flow and accumulate in low-lying areas, with an explosion limit of 5% to 33%.
Liquefied petroleum gas is generally a colorless gas or a yellow-brown oily liquid and belongs to a low toxicity class. Common symptoms of poisoning include dizziness, headache, excitement or lethargy, nausea, vomiting, pulverization, etc. In severe cases, anesthesia and loss of consciousness occur. Liquefied petroleum gas is generally added with a special odor of aldehydes or sulfides to facilitate the detection of the presence of this gas.
2, the characteristics of the accident (1) rapid proliferation, a large range of hazards. Liquefied petroleum gas generally leaks in the form of a jet, changes from a liquid phase to a gas phase, and the volume rapidly expands to form a large-area hazardous area.
(2) Explosive combustion. The lower limit of liquefied petroleum gas explosion is extremely low, and it is easy to form an explosive mixture with air after the explosion, and it may explode or burn in case of fire.
(3) The burning is fierce and the explosion speed is fast. The liquefied petroleum gas combustion flame temperature can reach more than 18000C, and the explosion speed can reach 2000-3000m/s.
(4) It is difficult to handle and requires high requirements. The factors such as the container, location, caliber and pressure of leakage of liquefied petroleum gas are different, the disaster situation is complex, the danger is high, and the professional technical requirements for disposal are high.
3. Disposal procedures and measures (1) Reconnaissance and detection Through the methods of inquiry, reconnaissance, detection, monitoring, etc., as well as measuring wind and wind direction, the gas concentration and diffusion direction of the leakage area are mastered. Identify the number, location and rescue route of people in distress. Find out the leakage container storage, leakage location, leakage speed, as well as safety valves, emergency shut-off valves, liquid level gauges, liquid phase tubes, gas phase tubes, tanks, etc. Find the number of tanks and total storage in the tank area, the storage capacity of the leak tanks and the storage capacity of the adjacent tanks, as well as the layout of pipelines, ditches and sewers. Understand the disposal measures that have been taken by the accident unit, the provision and operation of internal fire protection facilities, and the evacuation of rescue personnel. Find out the situation of the units in the warning area, the number of personnel, topographic features, power sources, fire sources and traffic roads. Master the location, reserves and water supply methods of fire water sources on site and around. Analyze and assess the extent of leakage spread and the risk factors and consequences that may cause explosive combustion.
(2) Evacuation of warnings to evacuate the area of ​​leakage and unrelated persons within the scope of the spread. According to the situation of reconnaissance and detection, the warning range is determined, and the critically-risk area, the light-risk area and the safety area are divided, and the warning signs and entrances and exits are set. Strictly control the personnel, vehicles and materials entering the warning zone, especially in the critically endangered areas, conduct safety inspections and make records. According to the dynamic detection results, adjust the warning range in time.
(3) Prohibit the fire source to cut off the strong and weak power supply in the accident area, extinguish the fire extinguishing source, stop the high-heat equipment, and implement anti-static measures. It is strictly forbidden to carry and use mobile phones and non-explosion-proof communication and lighting equipment. It is strictly forbidden to wear chemical fiber clothing and shoes with metal objects. It is strictly forbidden to carry and use non-explosion-proof tools. Motor vehicles (including rescue vehicles without explosion-proof devices) and non-motorized vehicles are prohibited from entering the warning zone at will.
(4) Safety protection Personnel entering the critically endangered area must implement secondary protection or above and take water gun cover. The level of protection of field workers must not be lower than three.
(5) Life rescue consists of a life-saving group, carrying life-saving equipment into the critically-hazardous area and the light-risk area. Take the correct rescue method and evacuate and transfer the people in distress to the safe area. The rescued personnel shall be registered, marked, and handed over to the medical emergency department for treatment.
(6) Technical support organization of accident units and experts and technicians in the petrochemical, meteorological, environmental protection and health departments to judge the accident situation, provide technical support, formulate emergency rescue plans, and participate in emergency rescue operations (7) on-site water supply to formulate water supply The plan selects the water source, selects reliable and efficient water supply vehicles and equipment, and adopts reasonable water supply methods and methods to ensure the fire water consumption.
(8) Dilution explosion-proof Enable fixed and semi-fixed fire-fighting facilities such as accident unit spray pumps. Use spray water guns, screen seal water guns, set water curtains or vapor screens to dissipate accumulated and flowing gases, dilute gas concentrations and prevent the formation of explosive mixtures. The use of a mist jet forms a water curtain wall to prevent gas from spreading to important targets or dangerous sources. If the liquefied petroleum gas flows in the liquid phase along the ground, it can be covered with a medium multiple foam to reduce its evaporation rate and reduce the cloud cloud range. During operation, it is necessary to prevent the volatility of the liquefied petroleum gas from being accelerated due to the strong impact of the foam. For liquefied petroleum gas collected in buildings and trenches, doors, windows or trench covers can be opened and blown away by natural ventilation. At the same time, it can also be dispelled by explosion-proof mechanical air supply. It is forbidden to directly impact the tank and the leaking part with direct current water to prevent the static electricity from accumulating and discharging due to the impact of strong water flow.
(9) Closing the valve If the production device or pipeline leaks and the valve has not been damaged, it can assist the technician or under the guidance of the technician to use the spray water gun to cover and close the valve to stop the leakage. Tanks, pipes, valves, flanges leak, take appropriate plugging methods to implement plugging. Appropriate amount of water into the tank through the liquid phase valve, raise the liquid level, form the bottom water cushion in the tank, relieve the danger and cooperate with the plugging. Flange and liquid pipeline cracks leak. In cold regions and seasons, freeze leaks can be used. That is, fabrics such as sacks are used to forcibly wrap the flange leaks and water to freeze them to stop or reduce leakage.
(10) Turning the canned hydrocarbon pump into a can. The tank can be directly poured using a vehicle-mounted or mobile hydrocarbon pump under conditions that ensure site safety. When implementing on-site cans and cans in different places, it must be operated by professional technicians, and firefighters should protect them.
Inert gas replacement. The liquefied petroleum gas in the accident tank is replaced with another container or storage tank by using an inert gas such as nitrogen gas through a gas phase valve.
The pressure difference is inverted. Use the natural pressure difference caused by the horizontal drop to introduce the LPG of the accident tank into other containers, storage tanks or tank trucks to reduce the risk.
When carrying out the canning operation, the pipeline and equipment must be well grounded.
(11) Active ignition For active ignition, reliable ignition conditions must be available. Under the cooperation of experts and engineering and technical personnel, strict safety precautions are taken, and they are implemented cautiously and decisively.
Ignite conditions. 1When the top of the container is damaged and leaks, it can't be blocked and transported; 2 tank truck leaks in the densely populated area, can't be transferred or blocked; 3) If there is no ignition, it will bring serious consequences, and the ignition will ignite to form a stable combustion. If the amount of leakage has been reduced, the ignition measures can be actively implemented. If the gas diffusion in the field has reached a certain range, the ignition may cause deflagration or explosion, which will cause a huge shock wave, endangering the safety of other storage tanks, rescue forces and surrounding people, and causing unpredictable consequences. It is strictly forbidden to take ignition measures.
Ignite preparation. The spray water gun serving as cover and protection shall arrive at the designated position to confirm that all personnel in the danger zone have been evacuated. The area around the leakage point is not detected within the concentration range of the liquefied petroleum gas explosion, and ignition tools such as an ignition rod, a signal bomb, a fireworks, a magic bullet, etc. are used. Take the correct ignition method.
Ignite the opportunity. Leakage at the top of the tank, it is impossible to implement plugging at one time, and the gas leakage range and concentration are limited. At the same time, the spray gun dilution cover and various protective measures are ready to be ignited; the tank top burst has formed stable combustion, the tank body After being cooled and protected, the pressure in the tank is reduced, the flame is blown out by the wind, or destroyed by the cooling water flow, but there is still gas diffusion. If it is not ignited again, it may cause a hazard and should be ignited decisively.
(12) On-site cleaning Use spray water, steam or inert gas to clean the accident tanks, pipelines, low-lying land, sewers, ditches, etc. in the site to ensure no residual liquid (gas). Inventory personnel, collect and organize equipment and equipment. Remove the alert, make the handover, and evacuate safely.
4. Action requirements (1) Correctly choose the parking location and offensive route. The fire truck should choose the entrance and passage of the windward direction to enter the site and stop at the appropriate position in the upwind direction. Vehicles entering the danger zone must wear a fire hood. Use the water source in the upwind direction, select the offensive route from the upwind and side upwind directions, and set up the water gun position. The command should be placed in a safe area.
(2) It is necessary to guard against the explosion during the operation. Personnel entering the hazardous area must be professional and capable, protective measures should be in place, and spray guns should be used for screening. Take action with caution in lightning weather.
(3) Set up on-site safety officers, determine evacuation signals, and implement full-scale dynamic instrument testing. Once the on-site gas concentration is close to the explosive concentration limit, the situation is not effectively controlled, the danger is intensified, and when the safety of rescue workers is endangered, the evacuation signal should be issued in time. The first-line commander can decisively issue an emergency evacuation order without any request in an emergency. When evacuating, the equipment will not be collected or the vehicle will be opened, and the personnel will be evacuated quickly and safely.
(4) Reasonably organize the water supply to ensure continuous and sufficient on-site fire water supply, and maintain uninterrupted cooling and dilution of the LPG container and leakage area.
(5) It is forbidden for the operator to stay in the sewer of the leaking area or the top of the underground space, at the wellhead, at the ends of the tank, etc., to prevent damage caused by explosion.
(6) Do a good job in medical first aid. Cooperate with medical emergency force to prepare for on-site rescue. In the event of a casualty, immediate ambulance is performed.
(7) A certain number of fire trucks are mobilized to stand near the leak area. In the event of an explosion and combustion accident, immediately dispatch, control the fire, eliminate the danger
Liquefied petroleum gas is generally a colorless gas or a yellow-brown oily liquid and belongs to a low toxicity class. Common symptoms of poisoning include dizziness, headache, excitement or lethargy, nausea, vomiting, pulverization, etc. In severe cases, anesthesia and loss of consciousness occur. Liquefied petroleum gas is generally added with a special odor of aldehydes or sulfides to facilitate the detection of the presence of this gas.
2, the characteristics of the accident (1) rapid proliferation, a large range of hazards. Liquefied petroleum gas generally leaks in the form of a jet, changes from a liquid phase to a gas phase, and the volume rapidly expands to form a large-area hazardous area.
(2) Explosive combustion. The lower limit of liquefied petroleum gas explosion is extremely low, and it is easy to form an explosive mixture with air after the explosion, and it may explode or burn in case of fire.
(3) The burning is fierce and the explosion speed is fast. The liquefied petroleum gas combustion flame temperature can reach more than 18000C, and the explosion speed can reach 2000-3000m/s.
(4) It is difficult to handle and requires high requirements. The factors such as the container, location, caliber and pressure of leakage of liquefied petroleum gas are different, the disaster situation is complex, the danger is high, and the professional technical requirements for disposal are high.
3. Disposal procedures and measures (1) Reconnaissance and detection Through the methods of inquiry, reconnaissance, detection, monitoring, etc., as well as measuring wind and wind direction, the gas concentration and diffusion direction of the leakage area are mastered. Identify the number, location and rescue route of people in distress. Find out the leakage container storage, leakage location, leakage speed, as well as safety valves, emergency shut-off valves, liquid level gauges, liquid phase tubes, gas phase tubes, tanks, etc. Find the number of tanks and total storage in the tank area, the storage capacity of the leak tanks and the storage capacity of the adjacent tanks, as well as the layout of pipelines, ditches and sewers. Understand the disposal measures that have been taken by the accident unit, the provision and operation of internal fire protection facilities, and the evacuation of rescue personnel. Find out the situation of the units in the warning area, the number of personnel, topographic features, power sources, fire sources and traffic roads. Master the location, reserves and water supply methods of fire water sources on site and around. Analyze and assess the extent of leakage spread and the risk factors and consequences that may cause explosive combustion.
(2) Evacuation of warnings to evacuate the area of ​​leakage and unrelated persons within the scope of the spread. According to the situation of reconnaissance and detection, the warning range is determined, and the critically-risk area, the light-risk area and the safety area are divided, and the warning signs and entrances and exits are set. Strictly control the personnel, vehicles and materials entering the warning zone, especially in the critically endangered areas, conduct safety inspections and make records. According to the dynamic detection results, adjust the warning range in time.
(3) Prohibit the fire source to cut off the strong and weak power supply in the accident area, extinguish the fire extinguishing source, stop the high-heat equipment, and implement anti-static measures. It is strictly forbidden to carry and use mobile phones and non-explosion-proof communication and lighting equipment. It is strictly forbidden to wear chemical fiber clothing and shoes with metal objects. It is strictly forbidden to carry and use non-explosion-proof tools. Motor vehicles (including rescue vehicles without explosion-proof devices) and non-motorized vehicles are prohibited from entering the warning zone at will.
(4) Safety protection Personnel entering the critically endangered area must implement secondary protection or above and take water gun cover. The level of protection of field workers must not be lower than three.
(5) Life rescue consists of a life-saving group, carrying life-saving equipment into the critically-hazardous area and the light-risk area. Take the correct rescue method and evacuate and transfer the people in distress to the safe area. The rescued personnel shall be registered, marked, and handed over to the medical emergency department for treatment.
(6) Technical support organization of accident units and experts and technicians in the petrochemical, meteorological, environmental protection and health departments to judge the accident situation, provide technical support, formulate emergency rescue plans, and participate in emergency rescue operations (7) on-site water supply to formulate water supply The plan selects the water source, selects reliable and efficient water supply vehicles and equipment, and adopts reasonable water supply methods and methods to ensure the fire water consumption.
(8) Dilution explosion-proof Enable fixed and semi-fixed fire-fighting facilities such as accident unit spray pumps. Use spray water guns, screen seal water guns, set water curtains or vapor screens to dissipate accumulated and flowing gases, dilute gas concentrations and prevent the formation of explosive mixtures. The use of a mist jet forms a water curtain wall to prevent gas from spreading to important targets or dangerous sources. If the liquefied petroleum gas flows in the liquid phase along the ground, it can be covered with a medium multiple foam to reduce its evaporation rate and reduce the cloud cloud range. During operation, it is necessary to prevent the volatility of the liquefied petroleum gas from being accelerated due to the strong impact of the foam. For liquefied petroleum gas collected in buildings and trenches, doors, windows or trench covers can be opened and blown away by natural ventilation. At the same time, it can also be dispelled by explosion-proof mechanical air supply. It is forbidden to directly impact the tank and the leaking part with direct current water to prevent the static electricity from accumulating and discharging due to the impact of strong water flow.
(9) Closing the valve If the production device or pipeline leaks and the valve has not been damaged, it can assist the technician or under the guidance of the technician to use the spray water gun to cover and close the valve to stop the leakage. Tanks, pipes, valves, flanges leak, take appropriate plugging methods to implement plugging. Appropriate amount of water into the tank through the liquid phase valve, raise the liquid level, form the bottom water cushion in the tank, relieve the danger and cooperate with the plugging. Flange and liquid pipeline cracks leak. In cold regions and seasons, freeze leaks can be used. That is, fabrics such as sacks are used to forcibly wrap the flange leaks and water to freeze them to stop or reduce leakage.
(10) Turning the canned hydrocarbon pump into a can. The tank can be directly poured using a vehicle-mounted or mobile hydrocarbon pump under conditions that ensure site safety. When implementing on-site cans and cans in different places, it must be operated by professional technicians, and firefighters should protect them.
Inert gas replacement. The liquefied petroleum gas in the accident tank is replaced with another container or storage tank by using an inert gas such as nitrogen gas through a gas phase valve.
The pressure difference is inverted. Use the natural pressure difference caused by the horizontal drop to introduce the LPG of the accident tank into other containers, storage tanks or tank trucks to reduce the risk.
When carrying out the canning operation, the pipeline and equipment must be well grounded.
(11) Active ignition For active ignition, reliable ignition conditions must be available. Under the cooperation of experts and engineering and technical personnel, strict safety precautions are taken, and they are implemented cautiously and decisively.
Ignite conditions. 1When the top of the container is damaged and leaks, it can't be blocked and transported; 2 tank truck leaks in the densely populated area, can't be transferred or blocked; 3) If there is no ignition, it will bring serious consequences, and the ignition will ignite to form a stable combustion. If the amount of leakage has been reduced, the ignition measures can be actively implemented. If the gas diffusion in the field has reached a certain range, the ignition may cause deflagration or explosion, which will cause a huge shock wave, endangering the safety of other storage tanks, rescue forces and surrounding people, and causing unpredictable consequences. It is strictly forbidden to take ignition measures.
Ignite preparation. The spray water gun serving as cover and protection shall arrive at the designated position to confirm that all personnel in the danger zone have been evacuated. The area around the leakage point is not detected within the concentration range of the liquefied petroleum gas explosion, and ignition tools such as an ignition rod, a signal bomb, a fireworks, a magic bullet, etc. are used. Take the correct ignition method.
Ignite the opportunity. Leakage at the top of the tank, it is impossible to implement plugging at one time, and the gas leakage range and concentration are limited. At the same time, the spray gun dilution cover and various protective measures are ready to be ignited; the tank top burst has formed stable combustion, the tank body After being cooled and protected, the pressure in the tank is reduced, the flame is blown out by the wind, or destroyed by the cooling water flow, but there is still gas diffusion. If it is not ignited again, it may cause a hazard and should be ignited decisively.
(12) On-site cleaning Use spray water, steam or inert gas to clean the accident tanks, pipelines, low-lying land, sewers, ditches, etc. in the site to ensure no residual liquid (gas). Inventory personnel, collect and organize equipment and equipment. Remove the alert, make the handover, and evacuate safely.
4. Action requirements (1) Correctly choose the parking location and offensive route. The fire truck should choose the entrance and passage of the windward direction to enter the site and stop at the appropriate position in the upwind direction. Vehicles entering the danger zone must wear a fire hood. Use the water source in the upwind direction, select the offensive route from the upwind and side upwind directions, and set up the water gun position. The command should be placed in a safe area.
(2) It is necessary to guard against the explosion during the operation. Personnel entering the hazardous area must be professional and capable, protective measures should be in place, and spray guns should be used for screening. Take action with caution in lightning weather.
(3) Set up on-site safety officers, determine evacuation signals, and implement full-scale dynamic instrument testing. Once the on-site gas concentration is close to the explosive concentration limit, the situation is not effectively controlled, the danger is intensified, and when the safety of rescue workers is endangered, the evacuation signal should be issued in time. The first-line commander can decisively issue an emergency evacuation order without any request in an emergency. When evacuating, the equipment will not be collected or the vehicle will be opened, and the personnel will be evacuated quickly and safely.
(4) Reasonably organize the water supply to ensure continuous and sufficient on-site fire water supply, and maintain uninterrupted cooling and dilution of the LPG container and leakage area.
(5) It is forbidden for the operator to stay in the sewer of the leaking area or the top of the underground space, at the wellhead, at the ends of the tank, etc., to prevent damage caused by explosion.
(6) Do a good job in medical first aid. Cooperate with medical emergency force to prepare for on-site rescue. In the event of a casualty, immediate ambulance is performed.
(7) A certain number of fire trucks are mobilized to stand near the leak area. In the event of an explosion and combustion accident, immediately dispatch, control the fire, eliminate the danger
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