Fire prevention of the hottest dangerous chemicals

2022-08-14
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Fire prevention of hazardous chemicals

those with explosive, flammable, toxic, corrosive, radioactive and other dangerous properties are in transportation. Loading, unloading, production and use. Chemicals that can cause combustion, explosion, personal injury, property loss and other accidents under certain conditions during storage and storage are collectively referred to as dangerous chemicals. At present, there are about 2200 common and widely used species

dangerous chemicals are generally divided into explosives, compressed gases and liquefied gases. Flammable liquid, flammable solid. Spontaneous combustibles, inflammables when wet, oxidants and organic peroxides, poisons, radioactive substances, corrosive substances, etc

usually subject to friction. The excitation of impact, vibration, high temperature or other external factors can produce violent chemical reactions, instantly produce a large amount of gas and heat, make the surrounding pressure rise sharply, and explode, causing damage to the surrounding environment, accompanied by light. Objects with sound, smoke and other effects are all explosives. Including ignition equipment, detonating equipment, explosives and explosive drugs, firecrackers and other explosives

in order to facilitate storage, transportation and use, the gas is compressed or liquefied by pressure method and temperature reduction method and stored in the steel cylinder. In the steel cylinder, the gas in the state of rough surface is called compressed gas, and the liquid state is called liquefied gas. According to its nature, it can be divided into flammable gas, non combustible gas and toxic gas

flammable liquid refers to liquid substances that are easy to ignite and burn at room temperature. Most of these substances are organic compounds, many of which belong to petrochemical products. According to the regulations of our country, those whose flash point is equal to or lower than 61 ℃ are flammable liquids. Flash point liquids are divided into three categories: low, medium and high according to the flash point

generally, the ignition point is low, when encountering open fire. Heat, impact, friction or contact with some objects (such as oxidants) will cause strong. Solid substances that burn rapidly and may emit toxic smoke are called flammable solids. According to the level of ignition point and flammability, it can be divided into primary and secondary flammable solids

articles that do not need the action of external open fire, but cause self combustion due to chemical changes of the substance itself (usually due to slow oxidation), or due to the influence of external temperature and humidity, which heat and accumulate heat to reach its ignition point are called spontaneous combustion articles. According to the difficulty of spontaneous combustion, it can be divided into primary and secondary spontaneous combustion items. Substances that can react violently with water or moisture in humid air, release a large amount of flammable gas and heat, and make the temperature of flammable gas rise sharply to the spontaneous combustion point of the gas, or cause combustion or explosion when encountering open flames and sparks are called wet flammable substances. According to the severity of the reaction after being wet or damp and the magnitude of its harm, it can be divided into class I and class II flammable substances when being wet. In the oxidation-reduction reaction process, substances that can obtain electrons are called oxidants; Substances that lose electrons are called reductants, which are divided into: primary oxidants according to the strength and chemical composition of oxidation; Secondary oxidants and organic peroxides. All articles that enter human and animal bodies or contact skin in small quantities, can interact with body fluids and body tissues, disturb or destroy normal physiological functions, cause temporary or permanent pathological conditions of the body, and even endanger life are toxic. It is divided into four categories: first-class inorganic poisons, first-class organic poisons, second-class inorganic poisons and second-class organic poisons

objects that spontaneously and continuously emit rays that cannot be detected by people's sensory organs are called radioactive objects. Common ones are α Ray β Ray Υ Ray and neutron flow, etc. corrosive products are substances with relatively active chemical properties that can react with many metals, organic compounds, animal and plant bodies, etc. their main varieties are acids and bases

I. fire hazard

1. Fire hazard of explosives

(1) explosives have chemical instability. Under the action of certain external factors, they can produce violent chemical reactions at an extremely fast speed, and a large amount of gas and heat generated cannot escape in a short time, causing the surrounding temperature to rise rapidly and generate huge pressure to cause an explosion

(2) the initiation temperature of general explosives is relatively low. For example, as long as the temperature of mercury fulminate rises to 165 ° C, it can detonate; Although the ignition temperature of black powder is high, 270 ~ 300 ℃, it is very easy to explode in case of open fire

(3) some explosives and some chemicals such as acid. Alkali and salt react, and the products of the reaction are more explosive chemicals

(4) some explosives react with metals to produce more explosive substances. Especially the products of some heavy metals and their compounds have higher sensitivity

2. Fire risk of flammable liquid

(1) the flash point of flammable liquid is low, and the ignition point is also low (about 1 ~ 5 ° C higher than the flash point). What is the standard of pendulum film impact machine? Contact with the fire source is very easy to catch fire and burn continuously

(2) flammable liquids are almost all organic compounds, and the carbon and hydrogen contained in them are easy to react with oxygen and burn. When flammable liquid comes into contact with oxidants or oxidizing acids (especially nitric acid), it can react violently and cause combustion and explosion

(3) most flammable liquids have small molecular weight, low boiling point, easy to volatilize, high vapor pressure, and high vapor concentration on the liquid surface. They are very easy to catch fire and burn in case of open fire or flowers. And the vapor is generally heavier than air, which is easy to deposit in low-lying places or indoors, and it will not disperse for a long time, which increases the risk of fire

(4) the energy required for the ignition of flammable liquids is small, and only sparks with very small energy can ignite. Some flammable liquids are easy to accumulate static electricity when flowing and shaking, and spark generated by electrostatic discharge will cause combustion

(5) when the container containing flammable liquid is damaged or unsealed, the diffused flammable vapor is mixed with air. When it reaches the explosion limit, it can cause combustion and explosion in the presence of open fire or sparks

(6) the expansion coefficient of flammable liquid is relatively large, and it is easy to expand after heating, causing the sealed container to "drum", or even burst, and sparks will be generated during burst, causing combustion and explosion

styrene block copolymer (SBC) is added. 3. Fire risk of compressed gas and liquefied gas

(1) compressed gas, liquefied gas or pressurized dissolved gas stored in the cylinder expands when heated, and the pressure increases, which can make the cylinder explode

(2) some compressed gases and liquefied gases will react chemically after contacting each other, causing combustion and explosion

(3) combustibles such as grease are very easy to catch fire and burn or even explode in the impact plant of high-pressure pure oxygen

(4) compressed gas and liquefied gas are not only explosive, but also flammable and combustion supporting. Toxic and asphyxiating, under heat. It is easy to cause accidents such as combustion, explosion or poisoning under external effects such as impact and vibration

4. fire hazard of flammable solids, white burning goods and wet flammable goods

(1) the main characteristics of flammable solids are that they are easy to be oxidized, easy to decompose or sublimate when heated, and will often cause strong and continuous combustion in case of open fire

(2) flammable solids are subject to friction except that kindling and heat sources can cause combustion. Vibration, whining, etc. can also cause fire, combustion, and even explosion

(3) some flammable solids react violently with oxidants or acids (especially oxidizing acids), which will cause combustion and explosion

5. Fire risk of spontaneous combustion and wet inflammables

(1) most spontaneous combustion products have the properties of easy oxidation and decomposition, and the spontaneous combustion point is low. When the accumulated heat makes the temperature reach the spontaneous combustion point of the material, it will spontaneously ignite and burn

(2) in case of wet inflammables, they can react violently with water or moisture in humid air, releasing flammable gases and heat. It reacts more violently with acid and is very easy to cause combustion and explosion

(3) some inflammable materials when wet are also flammable or must be placed in flammable liquids (such as metal potassium, sodium, etc. must be immersed in the coal tank to isolate the air), and they encounter fire. Heat sources are also very dangerous

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