Fire and explosion prevention in the hottest petro

Fire and explosion prevention in the petroleum industry

fire and explosion often transform into complex situations

open fire and high temperature are very easy to cause explosion. The flame and high temperature cause the nearby containers to be heated, and the internal substances will volatilize and expand rapidly and explode, or the partially leaked oil and gas will fill the air to a certain concentration and explode. On site rescue personnel often suffer the most casualties in this case

explosion can also cause fire. The inflammables thrown by the explosion will cause a large fire

I. strictly control the ignition source

the ignition source is the key to cause leakage fire or explosion. If there is no ignition source, even if an explosive gas mixture is formed, it will not catch fire or explode. Therefore, eliminating ignition sources is the most practical, effective and operable measure to prevent fire

(1) immediately extinguish all kinds of open flames that may affect the area, such as open flames of heating furnaces and boilers, and stop welding. It is absolutely forbidden to use all kinds of open flames, especially at night or when the line of sight is not clear, it is forbidden to use matches, lighters, etc. for lighting

(2) control all electrical sparks. All electrical switches in the area shall remain intact and shall not be moved randomly. Turn off the portable BP machine. It is forbidden to play, because when the earpiece is picked up or put down, the coil in the machine will produce high voltage and electric sparks will appear at the fork spring

(3) the rescue tools must be the control valve between the servo valve and the ordinary proportional valve. One by one, the high-performance electro-hydraulic proportional directional valve uses explosion-proof tools. It is forbidden to use steel tools such as shovels. In case there is no such tools, they should also be wrapped with cloth or coated with butter and graphite. The cutting tools should be coated with a thick layer of butter

(4) motor vehicles such as cars, tractors and motorcycles that can produce sparks are strictly forbidden to enter, and reliable safety measures must be taken when entering

(5) anti static. While continuing the construction on the waterproof layer, open fire is strictly prohibited, we should also be vigilant against this arsonist hidden in the body

in the petroleum industry, the harm of static electricity is serious. From small open containers for storing oil to large oil tanks, fires caused by static electricity have occurred. An explosion was caused by employees wearing acrylic clothes and foam plastic sandals when they were moving in places with gasoline vapor. Six people were killed and 15 seriously injured on the spot

the friction of any two substances will produce static electricity. Due to the high resistivity and low dielectric constant of petroleum substances, it is easier to produce electrostatic sparks. When the electrostatic accumulation voltage reaches more than 300V and is close to objects that are not charged or have low potential, spark discharge will occur. For example, the casing needs temporary pressure relief at the initial stage of gas well production, and obvious electrostatic sparks can be observed in the translucent hose at night. A voltage of 2800v can be generated when people take off sweaters, and more than 10000 V can be generated when taking off nylon clothes. According to the experiment, when the liquefied petroleum gas leaks, the electrostatic voltage generated is as high as 9000v, and its discharge spark is enough to detonate

the protective measures against static electricity should be taken from two aspects: controlling the generation and accumulation of static electricity:

① select appropriate materials, and try to choose metal pipes to replace plastic pipes and rubber pipes; The oil loading crane pipe should be made of conductive oil resistant rubber pipe. If it is an ordinary rubber pipe, a metal copper wire can be added in the rubber pipe, and both ends are grounded; Electrostatic conductive coatings, such as electrostatic conductive unsaturated polyester resin, are sprayed on the floors of flammable and explosive workshops and warehouses, storage tanks and pipelines

② limit the flow rate and agitation, and the oil flow will generate static electricity. The faster the flow rate is, the more static charges will be generated. The flow rate of liquefied petroleum gas in the pipeline shall not exceed 3m/s

③ ensure the electrical connection and grounding of equipment and pipelines. All kinds of inflammable and explosive fluid and dust equipment must be well grounded, and electrical connection must be ensured. Wire connection should also be applied between pipe flanges. It should be noted here that most of the grounding clamps of the special grounding wires for oil tank trucks used in the transportation of gasoline, diesel and other finished oil products have poor contact, because the contact part between the grounding clamp and the oil tank is separated by paint, and the surface appears to be grounded, but in fact there is no grounding. The solution to the poor contact of the grounding clip: first, install a special copper grounding electrode at the rear of the oil tank truck, and it is strictly forbidden to paint on it; The second is to make a kind of large elastic grounding pliers, which can destroy the paint film

④ workers must wear anti-static work clothes and shoes or cloth shoes with conductive rubber soles. It is forbidden to wear chemical fiber clothes and shoes with iron soles. The fabric of antistatic overalls is mixed with small stainless steel wires and other conductive substances, and static electricity can be transmitted

II. Basic methods of fire extinguishing

according to the three elements of combustion, fire extinguishing measures such as removing combustibles, isolating oxygen (oxidant) and cooling combustibles below the ignition point can be taken:

1. Cooling

spray fire extinguishing agent directly on combustibles to reduce its temperature below the ignition point, so as to stop combustion. To put out a fire with water, its function is to cool and put out the fire

2. Isolate and extinguish fire

separate combustibles from oxidants to stop combustion. There are many specific measures, such as closing the valve to prevent combustibles from entering the combustion area; Plugging and leakage; Cover the combustibles with wet gunny bags, quilts, sand and foam or close the holes to prevent air from entering the combustion area

3. suppress fire extinguishing

spray chemical extinguishing agents (such as dry powder and halon 1211, 1301 halons) to interrupt the chain reaction of combustion and extinguish the fire. There are several common extinguishing agents for fire extinguishing:

the most commonly used extinguishing agent in the petroleum industry is Halon gas, which is characterized by high fire extinguishing efficiency, low cost and no harm to personnel, but it will be banned if it destroys the atmospheric ozone layer. Its substitutes include mf200tm, Inergen, water, foam, carbon dioxide, dry powder, etc

(1) mf200tm (heptafluoropropane)

the fire extinguishing agent developed in the United States to replace Halon 1301 total flooding fire extinguishing system is stored in steel cylinders

(2) smoke burning

is made of nitrogen (52%), argon (40%), carbon dioxide (8%)

(3) water

water is a common fire extinguishing agent. However, do not use water to put out the fire of oil products (such as gasoline, butter, engine oil, etc.), because the oil products will float on the water and spread the combustion, and do not use water to extinguish the burning electrical equipment, because it will cause circuit short circuit and casualties

① straight water and flowering water: the columnar water flow ejected by the straight water gun under the pressure of the water pump is called straight water; The water spouted by the blooming gun is called blooming water. This water flow can be used for the fire of general solid substances (such as the fire of storage tanks and rubber), as well as the fire of semi solidified heavy oil at room temperature

② foggy water: the water with the diameter of 40 ~ 100 m is sprayed by the spray water gun, which is called foggy water. For the leakage of liquefied gas, reed spray water gun should be used for rescue

in recent ten years, water mist fire extinguishing technology has received more and more attention. Water mist fire extinguishing can not only improve the utilization rate of water, but also reduce the loss of water stains. However, compared with direct flow water, flowering water and fog water have a shorter range and cannot be used from a long distance

(4) foam

it uses the foam layer to isolate the suffocation effect of air and the cooling effect of water to extinguish the fire, and is most suitable for the fire of flammable liquids (such as oil)

(5) carbon dioxide (CO2)

it is an effective substance for extinguishing fires in local spaces (such as engine rooms), which is usually filled in pressure steel cylinders with liquid. It should be noted that CO2 will instantly cool the burning substances to about -70 ℃. Sometimes the loss of the high stiffness main engine produced by the microcomputer screen hydraulic universal experimental machine produced by Jinan new era Gold Testing Instrument Co., Ltd. with the imported technology is greater than the fire itself

(6) dry powder

sodium bicarbonate dry powder and ammonium phosphate dry powder are mainly used in China, which have the characteristics of fast fire extinguishing, no corrosion, non-toxic and so on