[Fire-fighting vehicle] Rescue and rescue functions of vortex fire engines in chemical accidents

Abstract: The leakage of toxic gases in China's chemical industry, and the occurrence frequency of special disasters such as chemical explosions and misfires have increased in tandem with the growth rate of the chemical industry. The vortex firefighting firefighting engine is a kind of jet platform for extra powerful gas, decontaminant and fire extinguishing agent. In the emergency rescue of chemical accidents, it blows, dilutes, and removes toxic substances on the scene of the accident, and forcibly ventilates and disperses toxic fumes. The unique function of cooling the fire field is conducive to winning valuable time for rescue. In anti-drug rescue and fire rescue, it plays an important role in protecting people's life safety and eliminating poison and explosion accidents.

【Keywords】 vortex fire engine, chemical accident, rescue, decontamination

In 1996 l1 months, the Ministry of Public Security issued a "Circular on prevention and disposal of toxic events, chemical explosions and other disasters special work," and anti-virus assigns the task of rescue fire brigade. It can thus be seen that China’s efforts to prevent and dispose of toxic gas incidents, chemical explosions, and other special disasters have been included in the important agenda, El Cheng, and the deployment of such accident prevention and rescue efforts has started throughout the country. This article describes a new type of high-power special equipment that is suitable for emergency rescue of chemical accidents.

1 General situation of chemical accidents

In our industrial accidents, chemical accidents are quite serious. The frequency of accidents with the rapid development of China's chemical industry can be described as synchronous growth. 3O recent years, China's chemical industry has developed rapidly, ethylene production from the early 7O's annual production of less than 2O million tons to late 8O has increased to an annual output of over 2 million tons. China has more than 3,000 organic chemical raw material manufacturers and can produce more than 8,000 organic chemical raw material intermediates . Organic compounds have soared from more than 2 million species in the 50 's to more than 7 million species. Many organic compounds have flammable and explosive properties, and some also have different degrees of toxicity. As a result, the frequency and danger of chemical accidents are increasing. From the founding of the country to 1982 , chemical accidents that caused human poisoning and environmental pollution in China accounted for 13 of the total number of industrial accidents . 9 9 / 6 , increased to 27 by 1988 . 6; between (1969 - 1983) years, more than a thousand casualties from chemical accidents were 1O2. The explosion of chlorine cylinders in the Wenzhou Electrochemical Plant in 1979 caused more than 1,000 casualties; in 1991 , more than 900 people were poisoned and 41 died in the Shangrao-Xiamine accident in Jiangxi Province ; more than 500 people were injured in a fire accident at a dangerous goods warehouse in Qingshui, Shenzhen in 1993. 15 People die. In 1998 , a fire broke out in the chemical plant of the No. 1 electroplating factory in Shijiazhuang, killing 6 people and injuring 10 firefighters.

Worldwide, the frequency of chemical accidents is also increasing, and its harm is increasing. Since the 8O's, the world's more serious chemical accidents occur on average every year more than 300; chemical accident occurred nearly 40 years in an economic loss of more than $ 300 million amounted to nearly ten thousand from. December 2, 1984, on the outskirts of India's Bhopal Union Carbide a reservoir valve 45 tons of highly toxic methyl isocyanate leaked liquid failure of liquid, gas caused 3150 people were killed, more than 50,000 people blind, 2 million people have been seriously poisoned; June 3, 1989, explosion of liquefied gas pipeline rupture former Soviet Union City, east of the Ural Erwu law occurred, destroying buildings within a radius of four kilometers, to blow up a train traveling in two, resulting in more than 400 people were killed and 600 wounded; March 1995 2O El, shocked Japan's "sarin gas attack," the Tokyo subway, killing 10 people were killed and more than 5,500 people sent to hospital.

2 The role of vortex firefighting vehicles in rescue of chemical accidents

The characteristics of chemical accidents are sudden and strong, and occur instantaneously, which makes the prevention work unprepared. Poisonous substances have a large amount of leakage, spread across a wide area, have a wide range of poisons, spread rapidly along the wind direction, and have special forms of injury, which are extremely harmful to human life. Therefore, the emergency response to a chemical accident requires a rapid response and can quickly control the vicious developments of the situation; the rescue work must be effective and effective, and timely rescue and treatment of the poisoned personnel. The main role of turbojet firefighting ( Figure 1) in the rescue of chemical accidents is:

1) Dilute and blow toxic gases. Taking chlorine as an example, only 2 per cubic meter of air are required . 5 mg of chlorine can cause death. A 70- ton tank of liquid chlorine can form 700 million cubic meters of gaseous chlorine gas, spread out close to the ground, and endanger a very large area. The turbojet engine on turbojets operates at a high speed, with a power of 5,000 kilowatts. At a nozzle velocity of 500 meters per second , it can inject more than 3,000 cubic meters of high-speed airflow per minute. The air forms a large speed difference, which mixes and drives the air around the high-speed airflow, creating a powerful local "artificial storm" with a flow rate of tens of thousands of cubic meters per minute, blowing rapidly over a distance of (30 to 110) meters. Disperse and dilute toxic gases and rescue people who have been seriously injured by toxic gases. After testing, 1 turbojet engine 5 to the working rotational speed 10000 rev / min, air velocity 50 meters away from the spout remains (20 ~ 25) m / s 90 m is (5 to 12) m / sec 110 meters is (5-6) m / sec, "artificial storm" dry covers several square meters. According to the site conditions of the chemical accident, if there are conditions, (2 to 3) or more vortex fire engines should work side by side, which can play a good role in dispelling and diluting the toxic gases leaked out in the wind. The vortex fire truck should be placed in the upper wind position to obtain excellent blowing effect.

This method is suitable for blowing and leaking toxic gases such as carbon monoxide, hydrogen sulfide, hydrogen fluoride, chlorine, ammonia, and phosgene. It can also be used to blow out and dilute leaked liquefied petroleum gas, artificial gas, natural gas, and other combustible gases. Does not form explosive concentrations and shields rescue personnel from plugging.

2) Decontamination. The vortex fire truck can also be used for large-scale rapid decontamination. The purpose is to quickly dilute chemical toxicants and reduce their toxic effects on people and the environment.

Common decontamination methods are:

1 physical decontamination. The large flow of sprayed water sprayed by turret fire engines has the advantages of fine spray mist size, high jet strength, long spray distance, and large coverage area. It can absorb and dissolve ammonia, chlorine, and hydrogen sulfide in the air. Gas, reducing the content of toxic gases in the air, achieve the purpose of physical decontamination. The spray distance of the vortex fire engine spray water can reach up to 110 meters .

2 oxidation, chlorination, decontamination. Add appropriate amount of bleaching powder, sodium hypochlorite, etc. in the water tank of the vortex fire truck to make it dissolve in water and then spray it with misty water to the toxic gas and the poisoned area, and achieve disinfection by oxidizing and chlorinating the toxic substances. purpose.

3 Neutralization and decontamination. Add hydrated sodium hydroxide, calcium hydroxide ( lime water ) , ammonia, sodium carbonate, sodium bicarbonate, etc. into the water tank of the vortex fire truck. Dissolve it in water and use mist water to spray toxic gases such as hydrogen sulfide and chlorine. This causes it to neutralize and dilute the toxic gases in the atmosphere to achieve the purpose of disinfection. For alkaline toxic gases such as ammonia, a small amount of acid liquid can be added to the turret fire truck tank. After atomizing and spraying, it can neutralize and dissolve high concentrations of ammonia in the air to achieve rapid disinfection.

4 Blowing away. The vortex fire trucks can participate in the disposal of on-site decontamination similar to the Sarin Gas Incident that occurred in the Tokyo Metro, and their decontamination methods are mainly blown off. Utilize the powerful blowing ability of the exhaust gas flow of the turbojet engine to remove the residual poisons in the poisoned area by tail gas blowing or exhaust gas to water mist blow-off, air flow dilution and removal of poisons to reduce the residual amount of on-site poisons to the safety alert value. The following, in order to restore the normal use of infected areas and infected devices as soon as possible.

3) Forced ventilation and cooling. The vortex fire truck is still a huge power-driven ventilator, capable of blowing large volumes of high-oxygen air ( oxygen content in the exhaust of turbojets is around 2O ) and forced to blow out corridors, tunnels, railway tunnels, and subway passages. The toxic fumes in the turbulence; the mist sprayed by turret fire engines, and the good cooling and absorption of toxic gases ( such as ammonia, hydrogen sulfide, etc. ) help to rescue the victims in the buildings.

The large flow of water spray sprayed by the vortex fire engine can effectively block the heat radiation in the fire and make the rescued personnel enveloped in the mist. It is suitable for the rescue of passengers and crew members in the passenger cabin in the accident of aircraft accident. And people trapped by fire in tunnels.

3 vortex fire trucks other rescue functions

The vortex fire trucks can quickly wash and dispose of weapons and equipment contaminated with chemical poisons and construction vehicles and vehicles contaminated with radioactive substances. The procedure is: The equipment to be decontaminated is passed through the air in a serial manner at a speed of (3 to 5) km/ Ij from the position of the nozzle of the vortex fire engine (4---5 meters ) . The exhaust nozzle of the turbojet is used for swinging up and down and left and right. The high-speed exhaust-water mist produces a strong purging and flushing action on the surface of the decontaminated equipment, blowing off the toxic and radioactive substances contaminated by the surface. Using two turbojets asymmetrically placed on both sides of the road to be decontaminated, so that the left and right sides of the equipment are decontaminated. The decontamination capacity is: a medium degree of contamination of the tank camp can be completed every hour. Decontamination, or the completion of the decontamination of 3O large-scale construction machinery, the surface clearance rate of more than 90 %, the surface poison or radioactive material remains below the specified data. It is also possible to drive a vortex firefighting vehicle into an area contaminated with chemical poisons, perform on-site decontamination of the fixture, complete the on-site poison removal task as soon as possible, and restore the contaminated device as soon as possible.

4 Conclusion

The large-volume, high-velocity water jet, which has been used for many special purposes in many fields of national economic construction, has long been known to people. Conventional fire engines, riot vehicles, and cleaning vehicles all use jets as the main working means; large-flow, high-velocity jets also have many special uses in many special places of national economic construction. High-speed air flow, with a flow rate of over 3,000 cubic meters per minute and a jet power of several thousand kilowatts, is an extremely powerful jet platform that extinguishes oil well fires, sweeps snow from airport runways, clears desert sand, and rescues In addition to toxic gases, forced ventilation and the removal of toxic fumes when the fire is extinguished, they all have unique features that cannot be replaced by other equipment. These functions are being widely concerned, developed and utilized by people. With the rapid development of the world's chemical industry, in the increasingly concerned chemical accident rescue, the powerful local “artificial storm” created by the use of extremely powerful jet gas flow is toxic to the rapidly diffusing toxic gas. The concentration of gas, the reduction of chemical toxic gas disasters, and the completion of the decontamination of sites and installations, providing valuable time and space for emergency rescue work are of great significance. The vortex fire truck will become a powerful tool for emergency rescue in the event of chemical accidents, and it is also a new field of comprehensive safety technology equipment that is worth further exploration, development, application and industrialization.

This article comes from the "China Safety Science Journal" 2000 Volume 10, re-edited by China Rescue Equipment Network.