15 articles on the management of gas cylinders

There are many gas cylinder explosion accidents, and there are many lessons. Most accidents can be avoided, but because everyone does not pay attention to the use and operation, it leads to gas cylinder accidents.

1. Why does the acetylene bottle have to stand upright instead of lying down when it is stored and used?

Reason 1: The acetylene bottle is filled with filler and solvent (acetone), and when it is used horizontally, the acetone is easy to flow out with the acetylene gas, which not only increases the consumption of acetone, but also reduces the combustion temperature and affects the use, and at the same time produces backfire and causes the explosion of the acetylene bottle.

Reason 2: When the acetylene bottle is placed horizontally, it is easy to roll, and the bottle and bottle, bottle and other objects are easily impacted, forming excitation energy, resulting in the occurrence of acetylene bottle accidents.

Reason 3: Acetylene bottles are equipped with shockproof rubber rings, the purpose of which is to prevent collisions with each other during loading, unloading, transportation, and use. The rubber ring is an insulating material, and lying is equivalent to the acetylene cylinder placed on the electrical insulator, so that the static electricity generated on the gas cylinder can not diffuse to the earth, and gathers on the cylinder body, which is easy to produce electrostatic sparks, and when there is acetylene gas leakage, it is easy to cause combustion and explosion accidents.

Reason 4: When using, the acetylene bottle valve is equipped with a pressure reducer, a flame arrester, and a hose connected, because it is easy to roll horizontally, and it is easy to damage the pressure reducer, flame arrester or pull off the hose when rolling, resulting in acetylene gas leaking outward, resulting in combustion explosion.

2. Why should oxygen and acetylene bottles be stored separately?

Answer: Acetylene is flammable and oxygen is combustible. If there is a leak of acetylene, the acetylene mixes with the air, and when it encounters a spark or an open flame, a violent explosion will occur, and the explosion will destroy the oxygen cylinder and leak out of oxygen, so that the combustion of oxygen will make the explosion more violent. Uncontrollable. So the two of them can't be put together.

3. Why should the temperature of the bottle not be exposed to the sun?

Answer: The temperature of acetylene cylinder shall not exceed 40 degrees, the boiling point of acetone is 58 degrees, the higher the temperature, the faster the acetone volatilization, the precipitation of acetylene, so that the pressure in the cylinder increases sharply.

4. Why must there be residual pressure in acetylene cylinders and oxygen cylinders?

Answer: Leave a few kilograms of pressure in the bottle, so that the pressure inside the bottle is greater than the pressure outside the bottle, which can avoid the inflow of other gases and ensure the safety of use. Because acetylene has a very low explosion limit, it will explode when it reaches a certain temperature if it is mixed with a little air. Therefore, the exhaust port of the acetylene bottle must have a pressure reducing valve to prevent air from mixing into the bottle, otherwise there will be a risk of explosion next time it is used. Coupled with the pressure reducing valve, it is necessary to prevent the air pressure in the bottle from being less than the air pressure of the outside air, to avoid the air backflow into the acetylene cylinder, and the oxygen cylinder should retain the residual pressure of not less than 0.098~0.196MPa gauge pressure. The acetylene cylinder should retain the residual pressure of 49Kpa~98KPa in winter and 196KPa gauge pressure in summer.

5. Why can't the oxygen cylinder, especially the mouth of the cylinder, be contaminated or contact with grease substances?

Answer: Because oils, especially unsaturated lipids and acid fats, are easy to vaporize and exothermy. The spontaneous combustion of oil yarn and oilcloth is due to the oxidation in the air, the heat accumulation does not dissipate, and spontaneous combustion is caused when the spontaneous ignition point is reached. However, grease vaporizes slowly in the air, and the heat generated is quickly dissipated, and it is generally not easy to gather heat and spontaneously combust. Due to the strong oxidizing properties of pure oxygen, it can promote the violent combustion of combustibles. Oils and fats encounter pure oxygen, and their vaporization rate is greatly accelerated. At the same time, a lot of heat is released. The temperature rises rapidly and can quickly cause combustion. If the mouth of the oxygen cylinder is stained with grease, when the oxygen is rapidly sprayed out, the oil and fat will quickly undergo oxidation reaction, and the heat generated by the friction between the high-pressure air flow and the bottle mouth will further accelerate the oxidation reaction, so the grease contaminated on the oxygen cylinder or pressure reducing valve will cause combustion and even explosion, which is the reason why the oxygen cylinder, especially the bottle nozzle and the accessories in contact with oxygen, are strictly forbidden to contact with the oil.

6. Why do gas cylinders wear bottle caps?

Answer: Because most of the cylinder valves are made of copper alloy, which is relatively fragile, although some are made of steel, but because its structure is smaller than the bottle body, it is screwed on the bottle body to form a right angle between the bottleneck and the bottle valve joint, which is not only the fragile point of the bottle body, but also the prominent point of the bottle body, and is most susceptible to mechanical damage or external impact. If in the process of handling, storage and use, due to careless damage, the cylinder falls, falls, rolls or is hit by other hard objects, it is easy to break the joint of the bottle valve and the bottleneck.

The consequences of the bottleneck or bottle valve breakage: when the valve of the oxygen cylinder is broken, the high-pressure gas in the bottle of 150 kg/cm² causes the high-pressure gas in the bottle to lose control, so that the high-pressure gas is sprayed out, and its reaction force makes the gas cylinder rush in the opposite direction, which can damage the machinery and equipment and buildings, and even cause casualties; When the acetylene cylinder valve is broken, the flammable gas rushes out, forming an explosive gas mixture with the air, and exploding when encountering an open flame. The high-speed ejection of gas in the cylinder will be determined by the nature of the gas in the cylinder and bring more serious secondary accidents (such as fire, explosion, poisoning, etc.). If the bottle is filled with flammable gas, the static electricity generated by the intense friction of the high-speed jet or other ignition sources can cause combustion and explosion.

On the other hand, the bottle valve is exposed to the outside, and it is easy to invade dust or grease during handling and storage, which brings danger. Wearing a hard hat can prevent contamination and intrusion of dust or grease substances.

In order to eliminate the above-mentioned dangers, the bottle making unit is required to be equipped with a safety helmet when the cylinder leaves the factory. When using gas, unscrew down the helmet and put it in a fixed place, put the bottle cap on and tighten it in time after use, and do not throw it away. Do not forget to wear a helmet when handling and unloading.

7. Why should acetylene bottles not collide?

Answer: The collision will cause the activated carbon to be broken, the expansion space will increase, the acetylene gas will accumulate, and it will be in a high-pressure state, which will cause the risk of explosion; At the same time, when the temperature rises, the gaseous acetylene undergoes polymerization and explodes.

8. Why is it required to load and unload lightly when handling gas cylinders, and it is strictly forbidden to throw, roll or collide?

Answer: Due to the violent collision or impact of the gas cylinder, an explosion accident will occur, and the consequences will be very serious. In the process of loading and unloading gas cylinders in a Shanghai enterprise, an employee was hit and died on the spot!

9. Why can't oxygen cylinders be lifted?

A: Oxygen cylinders are high-pressure vessels, which are prone to explosion if accidentally dropped. If it is transported in large quantities, there is a special container for oxygen cylinders, which is suitable for one-time transportation, loading and unloading of multiple cylinders.

10. Why does the acetylene cylinder explode?

Answer: The cause of the explosion of acetylene cylinders is mainly caused by the decomposition of acetylene due to the sharp rise in temperature and pressure.

Characteristics of acetylene decomposition: If tempering occurs, the temperature of the wall of the bottle rises (starting from the top of the bottle) or smoke and odorous gas escapes from the open bottle valve. It indicates that acetylene has begun to decompose, and if the acetylene cylinder is directly affected by flame or radiant heat, there is a danger of acetylene decomposition at any time.

Causes of acetylene decomposition: (1) welding tempering; (2) External heating (there is a burning substance near the acetylene cylinder, and there are tools such as welding torches or cutting guns that have not been extinguished on the cylinders); (3) Acetylene fire near the cylinder valve or pressure reducer; (4) Severe shock or vibration.

Precautionary measures: (1) install flame arresters; (2) It is strictly forbidden to expose the bottle to the sun, heat the bottle or be close to the heat source; (3) It is strictly forbidden to hang unextinguished welding torches or cutting guns and other tools on acetylene cylinders; (4) Handling should be light loading and unloading, to avoid violent impact or vibration.

11. Why can't oxygen tape and acetylene hose be mixed?

A: Oxygen tape is a high-pressure tube, and acetylene tape is a low-pressure tube; In addition, the acetylene tube sometimes produces a slight tempering during use, and there will be carbon deposits in the pipe, which will cause an explosion when the carbon deposits are mixed with oxygen.

12. Why can't gas cylinders be mixed and mixed?

Answer: If the cylinder is filled with other gases, a violent explosion accident will occur, and the consequences will be very serious.

13. Why should the lower part of the oxygen cylinder be insulated when it is used at the same operation site as the electric welding?

A: In order to avoid the gas cylinder being electrified. When working with a welder (which is a premise), the bottom of the oxygen cylinder is insulated to prevent the cylinder from becoming electrified. Metal equipment such as pipes in contact with gas cylinders should have good grounding devices to prevent static electricity from causing combustion or explosion accidents.

14. Why can't acetylene bottles be used on insulators?

Answer: The ignition energy of acetylene is only 0.019 millijoules, and a small electrostatic discharge (a few millijoules) can ignite (detonate) acetylene. Acetylene flowing or leaking in the gas pipeline will generate static electricity, and any form of electrostatic discharge may ignite acetylene. Since acetylene does not require oxygen for combustion and explosion, there is a high possibility of explosion after ignition. If the acetylene cylinder is directly grounded so that it cannot be electrostatic, it will certainly not explode naturally.

15. Why should the copper content of the alloy be less than 70% when copper alloy appliances are used in acetylene bottles?

Answer: After long-term contact between acetylene and copper and silver, explosive compounds acetylene copper and acetylene silver will be generated, which can cause explosion when subjected to severe vibration or temperature as high as 110 ~ 120 °C.

Source: Gas Cylinder Safety

Editor: Lu Ningping

First trial: Dong Huaiyu

Second trial: Gu Yan

Third trial: Yang Hong

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