Most petrochemical raw materials and products are flammable and explosive, and their own or combustion products are toxic. Once a fire breaks out, it will cause great harm to people's lives and property. However, petrochemical products are an important part of social and economic development, one of the pillar industries of the national economy, and play an irreplaceable role in social and economic development. Therefore, it is urgent to make an in-depth analysis of petrochemical fire, find out its causes, and take targeted measures to effectively prevent and control fire accidents. According to the characteristics of petrochemical fire fighting, this paper analyzes and discusses the key links in the fire fighting process, briefly analyzes and discusses the characteristics and some experiences of petrochemical disasters and accidents, and on this basis, briefly analyzes the areas that need to be improved in petrochemical fire fighting, hoping to minimize the impact and loss of petrochemical fire accidents and provide reference and help for petrochemical fire fighting in the future.

Keywords: petrochemical industry; Fire fighting; Key links; trait

Abstract: Most petrochemical raw materials and products themselves or combustion products are flammable, explosive and toxic. Once a fire breaks out, it will do great harm to people's lives and property. However, petrochemical products are an important part of social and economic development, one of the pillar industries of the national economy, and play an irreplaceable role in social and economic development. Therefore, it is an urgent task to deeply analyze the petrochemical fire, find out its causes, and take targeted measures to effectively prevent and control fire accidents. According to the characteristics of petrochemical fire fighting, this paper analyzes and discusses the key links in the fire fighting process, briefly analyzes and discusses the characteristics and some experiences of petrochemical disasters, and on this basis, briefly analyzes the improvement of petrochemical fire fighting, hoping to minimize the impact and loss of petrochemical fire accidents and provide reference and help for future petrochemical fire fighting work.

Keywords: petrochemical industry; Fire fighting; Key links; trait

catalogue

Chapter I Characteristics of Petrochemical Fires

1. 1 wide spread 4

1.2 long duration 4

1.3 More potential hazards 4

1.4 Subsequent loss of 5%

Chapter II Difficulties in Fire Fighting in Petrochemical Industry 5

2. 1 explosion danger, arduous combat task.

2.2 The fire risk is high and the fire is easy to mutate.

2.3 complex process equipment, fire detection is difficult 6

Chapter III Countermeasures for Petrochemical Fire Disposal

3. 1 cooling explosion-proof 6

3.2 Close the valve and cut off the material 6

3.3 Blocking and dredging 7

3.4 Detection and Explosion Detection 7

Chapter IV Fire extinguishing mechanism of ABC dry powder extinguishing agent 6

4. 1 Fire extinguishing mechanism of Class A fire 6

4.2 Mechanism for Extinguishing Class B Fire6

4.3 Fire extinguishing mechanism of Class C fire 7

Conclusion 7

Reference 9

Thank you 10

Chapter I Characteristics of Petrochemical Fires

Petrochemical fires are characterized by large burning area, many fire spots, easy to rekindle and re-explode, and difficult to extinguish. The fire situation is complicated, and the explosion will cause great economic losses and casualties. Therefore, it is very important to analyze and understand the characteristics of petrochemical fires and prevent them effectively. Its characteristics are mainly manifested in the following aspects:

1. 1 has a large price difference.

Once a fire breaks out in petrochemical enterprises, its harmfulness is immeasurable, because the high temperature caused by the fire will volatilize toxic components in petrochemical products and attach to buildings and air. This poisonous gas spreads everywhere with the air. If there is wind, the spread of these toxic gases will greatly increase, from several kilometers to several provinces and countries. It can be seen that the fire hazards in petrochemical industry have a wide range and great influence, and it is difficult to carry out the follow-up fire fighting work.

1.2 has a long duration

Because there are many uncertain factors in the petrochemical fire scene, and the hazards caused by petrochemical products are greatly affected by weather and other factors, it is easy to spread with the wind and cause harm, so it is impossible to put out the fire blindly. In addition, unlike ordinary fires, petrochemical products themselves need a variety of fire extinguishing tools to put out the fire fundamentally, and once a fire breaks out, petrochemical products will produce a large number of combustible gases, resulting in multiple hidden fire points, so it is difficult to find all the fire points at once. Even if the fire point is found and put out, it is likely to produce secondary combustion in the next fire fighting work, so it is often put out many times by one fire point, which prolongs the time of petrochemical fire fighting and the duration of harm caused by petrochemical fire. Therefore, in many types of fires, the fire fighting in petrochemical units is usually a long-time and harmful combat action.

1.3 is potentially dangerous.

Because of the particularity of chemical products in refineries and chemical plants, there are always many potential dangers in fire fighting. For example, fire causes chemical products to produce a lot of toxic gases, and gas poisoning will occur if protective measures are not in place, endangering health and even life. Moreover, there will be secondary explosion and secondary combustion after the fire, and the time and power of the secondary explosion and secondary combustion are immeasurable. Once the secondary explosion or secondary combustion occurs in the process of fire fighting, firefighters will be placed in a very dangerous situation, and the chances of survival are generally very slim. Therefore, there are many potential dangers for firefighters in the process of fighting petrochemical fires.

1.4 The subsequent losses are relatively large.

The loss of fire is not only manifested in the casualties of materials, equipment and personnel, but also includes other potential economic losses, such as the economic losses of other commercial production affected by fire. Compared with ordinary civil building fires, petrochemical fires have caused greater losses and impacts in terms of material and casualties, and the economic losses caused are several times that of other production enterprises. The explosion of 20 15 Tianjin port 8. 12 "put Tianjin at the forefront of public opinion. Foreign media estimated that the direct economic losses caused by the big bang amounted to tens of billions of euros, equivalent to more than 70 billion yuan.

Chapter II Difficulties in Fire Fighting in Petrochemical Industry

2. 1 explosion danger, arduous combat task.

On the whole, the most important feature of petrochemical fire is inflammable and explosive. If there is an explosion (physical explosion or chemical explosion, or both), it will cause very strong destructive power and cannot be prevented.

Once a fire breaks out in a petrochemical unit, the flame can reach tens of meters in an instant. If there is a fire in a petrochemical plant, the heated container equipment is prone to physical explosion, and the leaked combustible gas or steam is prone to chemical explosion, and explosion and combustion often go hand in hand.

Whether it is a physical explosion or a chemical explosion, it will cause the surrounding buildings (structures) to collapse, the pipeline equipment to be displaced and broken, and the fuel will splash and flow, which will make the fire situation more complicated and bring great difficulties to the fire fighting.

2.2 The fire risk is high and the fire is easy to mutate.

Generally speaking, the materials in petrochemical plants are inflammable and explosive, and more than half of the products are combustible substances such as diesel oil, lubricating oil, aviation kerosene, alcohol, banana oil, turpentine, paint, chemical raw materials, asphalt, naphtha and paraffin. In addition to separating combustible gases such as carbon monoxide, methane, propane, butane, ethylene and propylene from crude oil, heavy oil is lightened, oil is upgraded and refined. If there is a fire, it will not only lead to gas overflow, but also form vertical fire and vertical fire, and it will expand the area of the fire to a certain extent, making it possible to spread.

In case of fire, backfire will occur under the action of heat conduction, which will lead to explosion of other equipment. In short, after the fire, its burning and explosion will be explosive, which is not only very destructive, but also difficult to put out the fire with the best rescue time.

2.3 Complex process equipment makes fire detection difficult.

Petrochemical enterprises often use multiple pipelines to connect, whether it is the connection between storage tanks or the connection between equipment, it is a whole set of processes, which are not only complicated in process, but also produce and store a variety of dangerous chemicals, and even many chemicals that firefighters are not familiar with or understand. In this case, it will be difficult for firefighters to take effective fire extinguishing schemes during the fire extinguishing process. In addition, after some petrochemical accidents, the burning area at the accident site is relatively large. If there are no special equipment and testing instruments for fighting petrochemical fires, it is difficult to investigate the fire situation in a short time, which leads to the inability to objectively and accurately grasp the accident data, let alone effectively formulate a feasible fighting plan, which delays the fighter plane and brings great difficulties to the fire fighting or emergency rescue work.

Chapter III Countermeasures for Petrochemical Fire Disposal

3. 1 cooling explosion-proof

Cooling and explosion-proof is the primary task of the public security fire brigade after its arrival. If all or part of the devices and the ground are burning at the site, we should first try to put out the flowing fire on the ground with foam, spray foam on the ground and adjacent groove surfaces, and implement foam covering protection to curb the spread of the flowing fire. On this basis, the accident device and adjacent equipment should be cooled from top to bottom in all directions. When cooling, priority should be given to important devices, and high-pressure fixed guns and semi-fixed fire hydrant systems adjacent to the devices should be used for rapid drainage. The cooling water gun should swing back and forth, and can't stay in the same position, so as to prevent the equipment from being deformed due to uneven cooling, or the explosion-proof membrane bursting after the equipment explodes, or the equipment from cracking. During the cooling process, it is necessary to prevent the cooling from directly entering the reactor and expand the situation (many reaction catalysts are hydrophobic). In order to prevent the threat of material leakage and explosion to fire-fighting vehicles and battle positions, the parking distance of fire-fighting vehicles should be more than 50m, and the parking position, command position and water diversion position of vehicles should be set on the windward or windward side.

3.2 Close the valve and cut off the materials.

Closing valves and cutting off materials are effective means to reduce or eliminate accident hazards of petrochemical equipment. When implementing the tactical (technological) measures of valve closing and material cutting, it is necessary to understand the position and shape of the valve, the quantity and flow of materials during the reaction, and the technical requirements (such as speed and direction) when closing the valve, and it should be carried out with the participation of factory technicians. If the automatic control valve and emergency cut-off valve are still working, the material source can be cut off through the adjustment of the automatic control valve and emergency cut-off valve; When closing the valve manually, the maintenance valve and bypass valve on both sides of the automatic regulating valve should be closed at the same time. When closing the valve, the operator must make airtight protection and wear gloves. If the temperature is high and the radiant heat is strong, the operator should close the valve and cut off the material under the cover of the water gun.

3.3 Blocking and dredging

Leakage stoppage and diversion are two means of fire fighting in petrochemical plants. While cooling the petrochemical plant in all directions, we should find ways to stop the leakage. When plugging, plugging tools and sealant should be selected according to the specific situation of the leaking device (pipeline).

At present, there are three commonly used pressureless plugging technologies: welding plugging, bonding plugging and pressing plugging. There are more than ten kinds of plugging technologies under pressure, such as fixture plugging method, fixture glue injection method, plugging method, top pressure plugging method, drainage plugging method, winding plugging method, internal pressure plugging method, freezing plugging method and top pressure welding plugging method. Sparse transfer is a safe method to transfer materials. In petrochemical production plants, materials can be safely transferred to other production plants or recovery tanks (tanks) by using vent pipes and recovery pipes. For condensed liquefied gas or viscous liquid, nitrogen can be used for purging during transportation to accelerate the change and flow (30MPa nitrogen system is installed in petrochemical high-pressure polyethylene plant). Materials flowing on the ground can be transferred and recovered through ditches.

3.4 Detection and explosion measurement

The purpose of detection and explosion measurement is to know the concentration of combustible gas, provide on-site danger index for combatants at any time, and provide basis for command and decision. Determine the risk level through detection and implement safety warning. The investigation process should be constant, preferably relatively fixed and timed, and the investigation information should be reported to the headquarters at least once every half hour. If conditions permit, it is necessary to set fixed detection points in different directions, especially downwind and crosswind, and provide detection information to the headquarters at any time through wired and wireless networks.

Chapter IV Countermeasures for Petrochemical Fire Disposal

4. Fire extinguishing mechanism of1A fire

According to ABC dry powder, the A-class fire test is to build a cube with 78 pine trees with 38 mm×38 mm×65 1 mm joints, and then put the steel oil pan with 3.8 L 90 gasoline on the woodpile.

Next, when the fuel is burnt out, exit the oil pan and put out the fire at 1.8 m with a 3 kg ABC dry powder fire extinguisher. This is the process of class A fire extinguishing test.

The fire extinguisher sprayed ABC dry powder extinguishing agent on the stake, and the particles enveloped the wood in a mist, diluting and gradually isolating the air, thus suffocating the flame. At the same time, the dry powder fire extinguishing agent is attached to the wood surface.

Under the action of high temperature, the following decomposition will occur:

It is a very good flame retardant, which can prevent pine from burning. Ammonia also has the function of infiltration, which can drive away the air in wood fibers and accelerate the extinguishing of fire sources (wood fire doors are also soaked with ammonium dihydrogen phosphate).

4.2 Mechanism of extinguishing Class B fire

"ABC Dry Powder" stipulates that a steel oil pan with a diameter of 1750 mm, a height of 200 mm and a wall thickness of 2.5 mm is used in the Class B fire test, in which 29 L water and 60 L90 gasoline are put. After 60 s of ignition, use 3 kg ABC dry powder fire extinguisher for fire extinguishing test, which is the process of Class B fire extinguishing test.

Class B fire is actually a dual function of physics and chemistry.

(1) physical action. The fine powder sprayed by the fire extinguisher quickly formed a layer of glass fog above the oil pan, and the dense isolation layer blocked the air from entering, which led to the ignition being extinguished due to lack of oxygen. ABC dry powder fire extinguishing agent fell on the surface of oil layer, which prevented the volatilization of gasoline, and gasoline could not be mixed with air to extinguish the fire.

(2) chemical action. H+ and OH- are very active in the combustion reaction, and they are the key to the chain reaction. However, under the action of heat, ammonium dihydrogen phosphate can release a factor that captures combustion free radicals, as shown in formula (1), and thus a reversible reaction occurs, as shown in formulas (2) and (3).

The occurrence of reversible reaction greatly reduces H+ and OH- in the combustion reaction, thus slowing down the combustion and even interrupting the combustion reaction.

4.3 Fire extinguishing mechanism of Class C fire

ABC dry powder stipulates that it can extinguish class B fire, which can also be regarded as class C fire. Class C fire refers to electrical fire. Because of fear of electric shock, ABC dry powder fire extinguishing agent is used, so the extinguishing mechanism of Class C fire will not be described here.

Chapter V Conclusion

Although the disaster caused by petrochemical fire is terrible, it can be seen from the above that the harm caused by petrochemical fire can be effectively controlled within a certain range as long as the fighting work is carried out smoothly and effectively in time. As long as the combat strategy and tactics are reasonable and effective and the combatants are efficient, the harm can be minimized. Therefore, in the face of petrochemical fire, there is no need to panic excessively, and we should trust and cooperate with rescuers to ensure our personal safety. Petrochemical fire is extremely dangerous, which will have a great impact on social economy and people's lives and property safety. Therefore, to put out petrochemical fires, we must understand their basic characteristics and attach importance to the key links of fire fighting, so as to improve the fire fighting efficiency in essence.

To sum up, the fire of petrochemical equipment not only caused the property loss of petrochemical enterprises themselves, but also affected the social and economic development. There are no two identical fire sites in reality, so the disposal of petrochemical fire accidents must be realistic, fully analyze the accident site, and then formulate corresponding tactical measures. At the same time, according to the actual situation, our commanders are required to seize the favorable fighters, use tactics flexibly, and implement correct command at the right time in order to put out the fire.

The disposal of petrochemical fire is a complex system engineering. Only by analyzing and evaluating the petrochemical fire risk scientifically, accurately and comprehensively can reasonable measures and suggestions be put forward to effectively prevent chemical fires. The analysis of petrochemical fire protection in this paper still needs further study and improvement, so as to better prevent and put out petrochemical fires effectively, and better serve urban and rural planning and build a harmonious society. Therefore, doing a good job in fire fighting and rescue of petrochemical equipment can, on the one hand, reduce casualties and property losses of petrochemical enterprises and provide conditions for their future development; On the other hand, it can reduce the environmental pollution caused by fire, thus promoting the sustainable development of petrochemical enterprises.

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Express gratitude/gratitude

The successful completion of this paper is inseparable from the help of teachers and classmates. In the course of this struggle, it has brought infinite passion and harvest to my student career. In the process of writing my thesis, I encountered numerous difficulties and obstacles, all of which were spent with the help of my classmates and teachers. When I was looking for information in the school library, the teachers in the library provided me with many kinds of support and help, especially Mr. XX, my thesis advisor. Without her tireless guidance and help, she selflessly revised and improved my thesis, and there would be no final completion of my thesis. Here, I would like to express my heartfelt thanks to the teachers who have guided and helped me!

At the same time, I would also like to thank the scholars' monographs cited in this article. Without the inspiration and help of these scholars' research results, I will not be able to finish the final writing of this paper. At this point, I also want to thank my friends and classmates, who gave me a lot of useful information in the process of writing my thesis and also provided enthusiastic help in the process of typesetting and writing my thesis! Gold is not enough, no one is perfect. Due to my limited academic level, there are inevitably some shortcomings in this paper. Please criticize and correct me!