Emergency disposal of seven common dangerous chemicals Hazardous chemicals are generally characterized by flammable, explosive, toxic and harmful. In emergency treatment, it is necessary to understand the characteristics and take appropriate measures to deal with them properly and in a timely manner. The seven common dangerous chemicals described in this paper refer to liquefied petroleum gas, natural gas, cyanide, potassium permanganate, chlorine, liquid ammonia and gasoline. The emergency disposal measures are as follows:
(1) Liquefied petroleum gas
1. Liquefied petroleum gas is A fuel widely used in industrial production and daily life of residents, mainly composed of hydrocarbon media such as propane, propylene, butane, butene, etc., and also contains a small amount of impurities such as H2S, CO, CO2, etc., low carbon produced by petroleum processing. Molecular hydrocarbon gas (cracking gas) is compressed. Appearance and traits: colorless gas or yellow-brown oily liquid, with special odor; flash point -74 ° C; boiling point from -0.5 ° C to -42 ° C; ignition temperature 426 ~ 537 ° C; lower explosion limit [% (V / V )] 2.5; upper limit of explosion [% (V / V)] 9.65; density relative to air: 1.5 ~ 2.0; insoluble in water. 2. Incompatible materials: strong oxidants, halogens. 3. Hazardous characteristics: Class 2.1 flammable gas, extremely flammable; heated, exposed to fire or sparks can cause combustion; form an explosive mixture with air; steam is heavier than air, can spread along the ground, and vaporizes after fire Combustion; packaging containers can explode when heated, and cracked cylinders are in danger of flying. 4. Health hazard: If there is no protection, directly inhale a large amount of liquefied petroleum gas vapor with anesthesia, which may cause dizziness, headache, excitement or lethargy, nausea, vomiting, pulse slowness, etc.; severe cases may suddenly fall, urinary incontinence, loss of consciousness Even breathing stops; incomplete combustion can lead to carbon monoxide poisoning; direct contact with liquid or its jet can cause frostbite. 5. Environmental hazards: It is harmful to the environment and can cause pollution to the atmosphere. The residual liquid can also cause pollution to soil and water bodies. 6. Public safety: Vapor diffuses along the ground and tends to accumulate in low-lying areas (such as sewers, sewers, etc.), so stay at the upwind, do not enter the low-lying area; unrelated personnel should immediately evacuate the leak area at least 100 meters; evacuation has nothing to do Personnel and the establishment of a warning zone, traffic control should be implemented when necessary. 7. Personal protection: wear positive pressure self-contained breathing apparatus; wear anti-static insulation suit. 8. Large spill: Consider at least 800 m isolation (isolated area with a radius of 800 m centered on the leak source). Fire: If there is a storage tank, tank truck or tanker in the fire, it is 1600 meters (the isolation area with the radius of 1600 meters centered on the leakage source). 9. Poisoning treatment Skin contact: If there is frostbite, seek medical attention. Inhalation: Quickly leave the site to fresh air and keep the airway open. If breathing is difficult, give oxygen; if breathing stops, immediately perform artificial respiration and seek medical advice promptly. 10. Leakage Disposal (1) Establish a warning zone. Immediately according to the terrain, weather, etc., at least 800 meters from the point of leakage to implement comprehensive martial law. A warning line was set up, and obvious signs were set up to notify the police and surrounding personnel of the rapid evacuation in various ways and means, and all vehicles and unrelated persons were prohibited from entering the warning zone. (2) Eliminate all types of fire. Immediately stop power and cease fire in the warning zone and destroy all fires that may cause fire and explosion. Before entering the danger zone, spray the ground with a water gun to prevent sparks from being generated by friction and impact. The equipment should be grounded during operation. (3) Control the source of the leak. Stop or flip the container while it is safe to avoid liquid leakage. If the pipe is broken, it can be blocked by wooden wedges, plugging plugging or jamming method, and then temporarily sealed by high-grade quick-frozen cement covering method. (4) Diversion and pressure relief. If the process pipelines are in good condition, the liquid hydrocarbons can be introduced into the emergency tank through the outlet pipeline or the sewage pipeline, or the liquefied petroleum gas boundary can be raised above the leakage site by using the water injection lifting method. (5) Tank cover. From a safe distance, use a water gun with a watering gun and a fixed spray gun to align the tank wall and leak point to reduce the temperature and concentration of flammable gases. (6) Control the vapor cloud. If possible, use a boiler car or steam belt to vent the gas at the leak point to dissipate the combustible gas; cover the leaked liquid phase with a medium or multiple dry powder to reduce the evaporation of the liquefied gas; transfer the vapor with spray water (or forced air) The direction of the clouds is so wide that it spreads out in a safe place. (7) On-site monitoring. At any time, the flammable gas detector is used to monitor and detect the gas concentration in the warning zone, and the personnel are ready to evacuate at any time. (8) Precautions: It is forbidden to directly impact the leakage or leakage source with water; prevent the leakage of the leakage into the sewer, ventilation system and confined space; isolate the warning zone until the concentration of liquefied petroleum gas reaches 25% of the lower explosion limit. 11. Combustion and explosion disposal (1) Selection of fire extinguishing agent Small fire: dry powder, carbon dioxide fire extinguisher; Big fire: water curtain, misty water. (2) Close the valve to stop the leakage. Shut off the valve: If the valve is not burnt out, wear a fire-proof suit, with a pipe wrench, under the cover of the water gun, approach the device, close the valve, and cut off the air supply. Diversion and pressure relief: If the process pipelines are in good condition, liquid hydrocarbons can be introduced into the emergency tank through the outlet pipeline and the sewage pipeline to reduce the ignition tank reserves.