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This post was last edited by Du Er Zhang Jia Shun on 2020-3-31 at 16:17. (Industry) Basic knowledge on the safe use of natural gas. I. Concept: Natural gas is a flammable gas composed mainly of hydrocarbons, which is formed from geological organic materials under certain conditions through prolonged exposure to pressure, temperature, and catalysts. Its main component is methane. It is extracted from gas fields or oil fields, purified and processed, and then supplied to urban users as high-quality fuel. When mixed with oxygen (or air), it can catch fire or explode. At 0°C and 101.352 Kpa, the density of natural gas (methane) is 0.7174 Kg/Nm3, and its relative density (with the density of air taken as 1) is 0.5548; in other words, natural gas is about half as dense as air. Under low temperature and high pressure conditions, it can change from a gas to a liquid, with its volume reducing to 1/600 of the original value; it is flammable, explosive, and non-toxic. II. Components: Mainly CH4, with small amounts of ethane, H2, CO2, H2S, etc. III. Classification: Natural gas is classified into four categories based on the characteristics of the deposits and the composition of the gas: 1) Associated gas with oil: Natural gas that is extracted along with oil is known as oilfield associated gas. 2) Pure field gas: Gas extracted from natural gas wells, also referred to as pure natural gas. 3) Condensate field gas: Gas obtained by separating it from condensate oil that contains light petroleum fractions. 4) Mine gas: Gas extracted from coal seams underground in coal mines. IV. Characteristics: 1. Colorless. In the absence of hydrogen sulfide, it is a colorless and odorless gas that is lighter than air. 2. Cleaning. No slag, easy to use, and low cost. 3. High calorific value. It is more than twice that of artificial gas, and is a high-quality, efficient combustible gas (the calorific value of field gas is 34.69 MJ/NM3). 4. Flammable and explosive. When natural gas mixes with air, it can catch fire or explode in the presence of an ignition source; it can also be detonated by static electricity sparks. Under normal temperature and pressure, the explosive range of natural gas is 5%–15%. 5. Toxicity. Natural gas may contain small amounts of hydrogen sulfide, and it is odorized; inhaling too much of it can lead to poisoning. V. Natural gas is primarily delivered through pipelines, making it convenient to use. Before use, one only needs to open an account with the gas company, load a sufficient amount of natural gas onto an IC card, and then insert this card into the meter. Once the valve in the pipeline is opened, the natural gas is delivered to the valve of the gas stove; all that’s needed to use it is to light the stove. VI. Precautions 1. To prevent poisoning and fires or explosions, the following precautions should be observed: 1) Rooms where gas pipelines pass through or where gas appliances and equipment are installed must not be used as living spaces, nor should flammable and explosive materials be stored there, nor any other fuel-burning sources used. 2) Use gas facilities and appliances properly, and ensure adequate ventilation and exhaust in areas where gas is used. 3) The use of gas facilities and appliances that have not been approved by the gas management authorities or have reached their end-of-life period is strictly prohibited. 4) When using gas, combustible gas leak detectors should be installed in each gas-using operation room to ensure that leaks are detected promptly. 5) In the event of a gas leak, under no circumstances should any electrical equipment be used, including blowers; it is also forbidden to use mobile phones at the scene, and open flames must not be used for detecting leaks. 6) The installation of gas pipelines and equipment is carried out in strict accordance with **relevant technical specifications, through proper design, installation, and inspection, before they are put into use, in order to ensure the integrity of the gas supply and utilization facilities as well as their safety in use. Without on-site inspection, adjustment, and testing by professionals from the natural gas company, if users move the installation locations of pipelines and facilities on their own, there is no guarantee regarding their integrity, safety, or durability. Therefore, if the user’s gas usage environment changes or if modifications are needed to the natural gas facilities, it is necessary to apply to the natural gas company following the established procedures for unified inspection and approval of such modifications. Users are not allowed to move natural gas facilities without permission, expand the scope of gas use, or change the nature of gas utilization. 7) It is strictly prohibited to use open flames or smoke near gas pressure regulation stations (cabinets), boxes, and pipelines. No foreign objects should be placed on the gas pipelines, and it is not allowed to strike the pipelines or fittings with hard objects. In the event of a gas leak or any other abnormal condition, it is necessary to report it to the gas company immediately. 2. Safety precautions for industrial gas users: 1) Before ignition, check the exhaust capacity of the chimney, ensure that the exhaust fans and blowers are operating properly, that the safety equipment is functional, that the valves are closed, and that there is no gas leakage. If a leak is detected, fix the issue first before proceeding with ventilation or using a blower to clear the area; only after confirming that there is no gas in the room or furnace should ignition take place. 2) When igniting, ignite first and then open the valve. First, light the ignition rod; then use the lit ignition rod to aim at the combustion hole of the burner before opening the valve. For burners with forced air, open the air valve first and then the gas valve, increasing the flow gradually to prevent it from being too high and blowing out the ignition rod. If the ignition rod is blown out, close the gas valve immediately and purge the furnace; only after all gas has been removed can a second attempt at ignition be made. 3) During the combustion process, it is necessary to pay constant attention to adjusting the ratio of gas to air. If abnormal conditions such as tempering or de-tempering are detected, the gas supply should be stopped immediately, and efforts should be made to resolve the fault. 4) When stopping the fire, the gas valve should be turned off first. In the event of a long-term gas supply interruption, the main gas valve should also be closed, and the relief valve should be opened for venting. 5) Operators must remain at their posts, strictly follow safety operating procedures, and abide by labor discipline. It is prohibited to use lighters for boiling water or cooking, and sleeping in areas where gas pipelines and equipment are present is strictly forbidden. Gas use is strictly prohibited when there is no one inside; it is necessary to ensure that the fire is extinguished and the valves are tightly closed. Other sources of fire are also forbidden in the operation area. VII. Inspections and Maintenance 1. Regular inspections of gas pipelines, facilities, etc., are carried out, which include: (1) Buried pipelines: Checking for any abnormal phenomena such as unusual odors in the vicinity, withered plants around them, bubbling on the water surface, or sounds indicating a gas leak, in order to determine whether there is a leak ； Is there any occupation phenomenon? 2) Overhead pipelines: Check for any hanging objects ； There are overlaps for wires and cables, grounding devices, etc ； Leak checks are frequently carried out at all the joints and valves of the pipelines. (3) Metering and pressure regulating devices, valves, etc.: Check whether the valves are sensitive and functional, whether the gas pressure is stable and normal, and whether the meters and gas-using equipment are operating properly ； Check for gas leaks, etc. 2. Regular or irregular maintenance of gas pipelines, etc., which includes: (1) Regular emptying, rust removal, and painting of gas pipelines during spring and autumn ； (2) For issues identified during inspections of gas pipelines, they should be detected and resolved promptly. VIII. Leak detection methods: 1. Smell. Natural gas is always odorized; if there is a slight leak, the odor can be detected by the nose. 2. Listen. If the air leakage is severe, a hissing sound of leakage can be heard from a distance. 3. Look. After the gas equipment is turned off, if the flow meter continues to show movement, it indicates that there is a leak somewhere. 4. Inspection. Apply soapy water to the pipe joints to check for leaks; if bubbles appear, it indicates a leak. Note: Never use an open flame to detect leaks. IX. Emergency response to natural gas leaks: 1. Immediately close the upstream valves to cut off the gas supply, stop using the gas, and notify the natural gas company. 2. In the case of an outdoor leak, it is necessary to set up barriers at the scene to prevent people and vehicles from entering the area where the gas is leaking; also, the use of any tools that may generate sparks, such as mobile phones, should be prohibited at the scene. 3. In the event of an indoor leak, do not operate any electrical switches (such as turning lights on or off, fans, etc.) ； Do not use indoor phones, cordless phones, or mobile phones ； Carry out window ventilation in a timely manner ； And evacuate the people inside to the outside. 4. Be careful: never use any open flame (including matches or lighters) to locate the source of a leak. 5. If the situation becomes serious, all personnel should immediately evacuate the area and call 119 to report the incident. X. Safety inspection. In accordance with relevant laws and regulations such as the \"Jiangsu Province Gas Management Regulations,\" gas companies have the responsibility and obligation to conduct safety inspections on entities that use gas. These entities are required to actively support and assist the inspectors from the gas supply companies in carrying out these inspections in accordance with the law, by providing necessary documentation; they must also sign the inspection forms and affix their official seals to confirm this. Upon receiving a notice from the gas supply company regarding potential hazards or violations, industrial and commercial gas users must promptly carry out the necessary corrections as specified in the notice, and complete such repairs within the given time frame. Otherwise, the gas company has the right to suspend the gas supply, and the user shall be responsible for any losses resulting from those hazards or violations.