Air technology-the development of the gas industry

Air technology-the development of the gas industry

Chapter One Introduction

　　 1. The main components of air:

　　O2: 20.93%

　　N2: 78.03%

　　CO2: 0.03%

　　Ar: 0.932%

　　H2: 0.005%

　　 2. The development of the gas industry:

　　1, oxygen:

　　1) Cryogenic technology: It is the science and technology to study the process route, process equipment, and process method to make the material temperature lower than 102K (-153.158℃).

　　2) In 1902, Dr. Linde of Germany, the founder of cryogenic technology, developed the first oxygen generator. 10m3/h

　　3) In 1932, the Soviet Union developed a 100m3/h oxygen generator.

　　4) In 1953, my country copied a 30m3/h oxygen generator in accordance with the Soviet Union.

　　5) In 1978, my country developed a 3000m3/h oxygen generator.

　　2, dissolve acetylene:

　　1) In 1892, German scientist Willisson invented calcium carbide, which was widely used in lighting in 1911. Compared with propane and natural gas, calcium carbide (acetylene) has higher flame temperature z* and less oxygen consumption z*, so it is widely used in industrial welding and cutting. In 1896, French chemists Claude and Hess discovered that acetylene is very easy to dissolve in acetone, so they manufactured acetylene gas cylinders, invented a safe compression method for acetylene, and created the industry for dissolving acetylene.

　　 2) my country only had 11 acetylene factories in 1979 after liberation.

　　3. Liquefied petroleum gas:

　　1) In 1892, the Netherlands took the lead in using natural gas to obtain liquefied methane.

　　2) The supply of liquefied petroleum gas in my country started in 1965. It is widely used in life, automobiles, power stations and industrial fuels.

　　 Three, gas cylinder

　　1. In 1931, Japan produced a medium-volume (30-47L) seamless gas cylinder. In 1952, a welded gas cylinder (dissolved acetylene cylinder) was produced in accordance with the American ICC standard.

2. my country's gas cylinder manufacturing industry started late, so there are many and mixed gas cylinders, such as Germany, France, the United States, Italy, Japan, Austria, the Soviet Union, Yugoslavia and other countries, which have exceeded their service life and are basically eliminated and scrapped. , But there are still very few individual gas cylinders in overdue service, which poses great safety risks.

　　3. In 1957, the Northeast Machinery Manufacturing Plant in my country manufactured the first batch of (40L, 15Mpa) seamless steel gas cylinders according to Soviet standards. In 1983, there were 11 manufacturing plants in my country that could produce dissolved acetylene bottles, and in 1986, my country could produce 6 million LPG cylinders per year.

　　 Chapter Two, Basic Knowledge of Gas

　　 One, basic knowledge

　　1. Molecules and atoms:

　　Oxygen: O2 means: an oxygen molecule is composed of two oxygen atoms.

　　 Acetylene: C2H2 An acetylene molecule consists of two carbon atoms and two hydrogen atoms.

　　 Liquefied petroleum gas: components: propane, butane.

　　Propane: C3H8 consists of three carbon atoms and eight hydrogen atoms.

　　Butane: C4H10 consists of four carbon atoms and ten hydrogen atoms.

　　 Butane is further divided into: n-butane and isobutane.

　　2, pressure (pressure):

　　1) Nominal working pressure: the limited filling pressure of the contained gas at the reference temperature (generally 20°C).

　　 oxygen cylinder: 15Mpa,

　　 Acetylene bottle <2.5Mpa.

　　 LPG cylinders have no nominal working pressure, only filling capacity.

　　2) Water pressure test pressure: the pressure test pressure with water as the medium for testing the static pressure strength of the gas cylinder.

　　 oxygen cylinder: 22.5Mpa,

　　 Acetylene bottle: 3.5Mpa (pressure test),

　　 Liquefied petroleum gas cylinder: 2.4Mpa (pressure test).

　　3, temperature:

　　1), Fahrenheit: ℉, Celsius: ℃

　　2) Thermodynamic temperature: K 1 cal = 4.184 Joule

　　4. Quality:

　　 kilogram, Kg

　　 Oxygen bottle: 45-65Kg, including: bottle body, bottle valve and other non-removable safety accessories.

　　 Acetylene bottle: 45-55Kg, including: bottle body, bottle valve, packing, acetone and other non-removable safety accessories.

　　 LPG cylinder: 16.5Kg, including: bottle body, bottle valve, and other non-removable safety accessories.

　　 5. Volume (volume): liter, L

　　 oxygen cylinder: 40L

　　 Acetylene bottle: 40L

　　 LPG cylinder: 35.5L

　　 2. The state of matter:

　　1, solid: ice

　　2, liquid: water

　　3, gaseous state: air

　　4. Oxygen is gaseous in the bottle; acetylene and liquefied petroleum gas are liquid and gaseous coexistence.

　　 3. Classification of gas:

　　1. Critical temperature: As long as the temperature of a gas drops below a certain temperature, it can be isothermally compressed into a liquid temperature.

　　 2. According to the difference of critical temperature, the gas is divided into the following four categories:

　　1) Permanent gas: critical temperature <-10°C. Oxygen, nitrogen, hydrogen, etc.

　　2) High-pressure liquefied gas: critical temperature ≥-10℃, ≤70℃. Carbon dioxide, ethane, ethylene, etc.

　　3) Low-pressure liquefied gas: critical temperature ≥70℃. Ammonia, chlorine, liquefied petroleum gas, etc.

　　4) Dissolved acetylene gas: critical temperature 36.5℃, pressure 0.13Mpa. Dissolve acetylene.

　　 Fourth, the hazard of gas:

　　1. Combustibility: The combustion heat of most combustion gases is 2.39MJ/Kg, which is more than 6 times larger than the combustion heat of TNT explosives (0.39 MJ/Kg). Although the blasting force cannot be compared with the heat of combustion, it can be seen that once a leak occurs, the consequences are quite serious. In addition, liquefied gas has a low boiling point and is easy to vaporize. Therefore, flash vaporization (instant vaporization) caused by sudden pressure relief is a special phenomenon that ordinary gases do not have. Generally at 20-30%, this flashing phenomenon is particularly dangerous for combustible liquefied gases, because the rapidly evaporating gas does not have time to diffuse and stays in a certain space to mix with the air to form an explosive gas, which means that there is an explosion. Prerequisites. Moreover, the burning speed of liquefied gas (10.4mm/min) is more than twice that of gasoline (4.8mm/min), which shows that the fire risk is much greater than that of gasoline.

　　2. Toxicity: General gas has its toxic and side effects. It only depends on the amount and time the human body inhales it, and the degree of harm to the human body. Such as: oxygen, long-term oxygen enrichment (≥40%) is easy to get an oxygen-enriched disease, liquefied gas and dissolved acetylene inhalation concentration is too high, resulting in suffocation death. Therefore, in the process of filling, storage, transportation, and use of gas cylinders, it is necessary to prevent chronic human body poisoning caused by gas leakage and acute poisoning caused by gas spillage caused by accidents of gas cylinders.

3. Corrosiveness: Most bottled gases are non-corrosive media, but due to impure bottled gases and other reasons, the non-corrosive ones have turned into corrosive or even highly corrosive, such as: water in the oxygen cylinder is extremely corrosive. Easy to rust, etc.

　　4. Explosiveness: The phenomenon in which a substance changes rapidly from one state to another state, and emits a large amount of energy in an instant, and at the same time produces a huge sound, is called an explosion. Explosion is divided into physical explosion and chemical explosion. For example: Oxygen is forbidden, oxygen is a combustion-supporting material, and oil is a combustible material. At the same time, oxygen is a strong oxidant. Once it comes into contact with oil, it will explode easily when it encounters high temperature and high pressure; dissolved acetylene is due to its chemical nature Structural reasons, chemical properties are very unstable, it is easy to decompose and polymerize due to environmental changes (temperature, pressure), and its explosion limit is very wide (2.3-80.7%), so z* is prone to explosion. Liquefied petroleum gas has a low boiling point and is very easy to vaporize. Therefore, flash vaporization (instant vaporization) caused by sudden pressure release is a special phenomenon that ordinary gases do not have. Generally at 20-30%, this flashing phenomenon is particularly dangerous for combustible liquefied gases, because the rapidly evaporating gas does not have time to diffuse and stays in a certain space and mixes with air to form an explosive gas. The explosion limit of liquefied petroleum gas is 2.2-9.5%.

　　 Chapter 3 Overview of Gas

　　 1. Permanent gas: oxygen, hydrogen, nitrogen, inert gas. 　　1, oxygen:

　　1) Properties: colorless, odorless, and odorless gas.

　　2), manufacturing: air fractionation method, water electrolysis method.

　　3), use: smelting, welding, diving, hypoxia treatment.

　　4), hazards and protection:

　　A. Oxygen is a necessity for human life, but inhalation of pure oxygen will cause oxygen enrichment disease.

　　B. Liquid oxygen is a non-combustible liquefied gas, but it is very combustion-supporting. It will burn and explode if it leaks in combustible materials.

　　C, fire extinguishing agent: water mist, carbon dioxide.

　　 2. The difference between medical oxygen and industrial oxygen:

　　1) Different standards: Medical oxygen refers to the national mandatory standard "Chinese Pharmacopoeia" 2005 edition, while industrial oxygen refers to the national recommended standard GB3863-1995 "Industrial Oxygen".

2) Different quality control indicators: Medical oxygen detection control indicators include seven control indicators: purity (≥99.5%), moisture content, CO2, CO, pH, ozone, and other oxides, while industrial oxygen control indicators are only: Purity≥99.2%, moisture content≤100ml.

　　3) Different packaging materials: In addition to the qualified seamless steel cylinders for industrial oxygen, special bottles are also required for medical oxygen, and they are regularly dried and disinfected.

　　 2. Liquefied gas: carbon dioxide, ammonia, chlorine, liquefied petroleum gas, etc., taking liquefied petroleum gas as an example:

　　 1. Properties: colorless liquid or gas, with natural gas smell.

　　2. Uses: civil gas, automobiles, industrial raw materials.

　　3. Preparation method: recovery from natural gas, recovery from refinery.

　　4. Harm and protection:

　　1). Liquid contact can cause frostbite. Cold steam can damage the skin. Inhalation can cause headache, dizziness, confusion and suffocation.

　　2) Victims who inhale gas should quickly leave the scene and move to fresh air. If you stop breathing, give artificial respiration and ask a doctor for treatment.

　　3) Fire extinguishing agent: carbon dioxide, dry powder, water mist.

　　 Three, dissolve acetylene:

　　 1. Properties: colorless, odorless combustible gas.

　　2. Uses: organic synthetic raw materials, welding and cutting, medicine, instrument analysis.

　　3. Preparation method: calcium carbide method, methane cracking method, hydrocarbon cracking method.

　　4. Harm and protection:

　　1) Pure acetylene is not toxic, but it is suffocating to the human body. If the concentration is 20%, feel dizzy and have difficulty breathing; more than 40% will cause collapse.

　　2) When acetylene is inhaled, it becomes drunken and excited, and causes drowsiness, pupils are straight, pulse is weak and uneven, and memory loss after awakening.

　　3) Shoes with nails and chemical fiber clothing are not allowed in the workplace. Prohibit pure copper accessories.

　　4) Fire extinguishing agent: carbon dioxide, dry powder, water mist.

　　 Chapter Four, Cylinders

　　 1. Cylinder classification:

　　 1. In terms of structure, it is divided into seamless gas cylinders and welded gas cylinders.

　　 2. Material: steel gas cylinders, aluminum alloy gas cylinders, composite gas cylinders.

　　3, the filling medium is divided into: permanent gas cylinder, liquefied gas cylinder, acetylene gas cylinder.

　　 2. The structure of the gas cylinder:

　　1. Oxygen bottle: bottle cap, bottle valve, bottle neck, bottle neck, bottle shoulder, collar, cylinder, bottle root, bottle bottom (bottle seat).

　　2. Acetylene bottle: bottle cap, bottle valve, collar, cylinder, bottle bottom (bottle seat), fusible alloy stopper, filler.

　　3. Liquefied petroleum gas cylinder: shield, bottle lug, valve seat, cylinder, lining ring, bottle seat.

　　 Three, the color of the cylinder, the steel seal mark:

　　1, color:



　　A, oxygen bottle: bottle color: light blue font color: black font: oxygen

　　 B. Acetylene bottle: bottle color: white color: red text: acetylene must not be near fire

　　C, Liquefied Petroleum Gas Cylinder: Bottle color: silver-gray font color: red text: LPG

　　2, steel seal standard:

　　A, oxygen cylinder: P165

Air technology-the development of the gas industry

　　B, acetylene bottle:

Air technology-the development of the gas industry

　　 C, liquefied gas cylinder:

Air technology-the development of the gas industry

　　 Chapter 5, Filling of Cylinders

　　 1. Check before filling:

　　 1. Whether the gas cylinder has its own property rights;

　　2, the color mark of the cylinder;

　　3. The steel seal of the gas cylinder;

　　4. Gas cylinder body and accessories;

　　 5. The material of the bottle valve filled with gas and the thread type of the outlet connector;

　　6. ​​The relevant regulations on the service life and inspection cycle of gas cylinders;

　　7. Special requirements for cylinders containing oxygen or strong oxidizing gases, their cylinder bodies, cylinder valves, etc.;

　　 8. Determination of the amount of acetone dissolved in the acetylene cylinder;

　　9. Containers, manifolds and bottle sets of containers.

　　 2. Safety inspection during filling process:

　　1. Filling temperature: z*high temperature≤60℃.

　　2, gas flow rate: 8m?/h

　　 3. Filling time.

　　 3. Safety inspection after filling:

　　1, appearance;

　　2, leakage;

　　3, filling volume, bottle temperature;

　　4. Gas cylinder accessories;

　　 5. Warning labels.

　　 Chapter VI, Cylinder Inspection

　　 1. Inspection cycle:

　　 1. Oxygen cylinder: once every three years

　　2. Acetylene bottle: once every three years

　　3. Liquefied petroleum gas cylinder:

　　 The 1-3 inspections are conducted every four years,

　　 The fourth inspection is once every three years,

　　The corrosion of steel cylinders is serious, and inspections should be carried out in advance if they may affect safety.

　2. Inspection process:

Check and receive gas cylinders-residual gas, residual liquid treatment-bottle unloading valve, accessories (bottle valve inspection)-internal and external surface rust removal-original registration-bottle thread inspection-external surface inspection-internal surface inspection ( Wall thickness measurement, strength check)-sound inspection-weight and volume measurement-hydraulic test-drying-bottling valve-air tightness test-punching inspection stamp-coating-issued Inspection report-register and issue gas cylinders.

　　 Chapter 7, Safety Management of Cylinders

　　 1. Registration management:

　　 1. Establish "Cylinder Archives", implement dynamic management, timely submit expired gas cylinders for inspection and scrap gas cylinders that have expired, and delete them in the file.

　　2, gas cylinder inspection and registration management.

　　 2. Transportation, storage and use management:

　　 1. In accordance with the "Regulations on the Transport of Hazardous Chemicals", go through relevant procedures for safe transportation.

　　2. Carry out safe transportation in strict accordance with the "Regulations on the Transport of Dangerous Chemicals" and the "Cylinder Safety Supervision Regulations".

　　3. Cylinders are classified and stored in accordance with the "Cylinder Storage Management System", and anti-falling fences are set up. Pay attention to check whether the gas cylinder is leaking.

　　4. Personnel who use gas cylinders should go through certain use training and understand the relevant knowledge of the use of gas cylinders. Gas cylinders for field operations should be fixed to prevent sun and rain.