Two 3k chlorine compressors have been installed. Items that require special inspection prior to commissioning

In addition to compressing air, compressors are also used to compress various hydrocarbon gases, various inert gases, and various chemically active gases. The requirements for lubricating oils for gas compressor cylinders are now introduced separately for various compressed gases. 1. Natural gas: Mineral oil compressor oil is generally used for lubricating natural gas compressors. But natural gas is compressed by oil... In addition to compressing air, compressors are also used to compress various hydrocarbon gases, various inert gases, and various chemically active gases. The requirements for lubricating oils for gas compressor cylinders are now introduced separately for various compressed gases. 1. Natural gas: Mineral oil compressor oil is generally used for lubricating natural gas compressors. However, natural gas is absorbed by the oil, reducing its viscosity; therefore, the viscosity grade of the oil used should generally be higher than that of the oil used in air compressors of the same model and under the same pressure. The content of condensables above ethane in different types of natural gas ranges from 2–3 Ml/m3 for dry gas, 13–40 Ml/m3 for lean gas, and 40–54 Ml/m3 for wet gas. To address moisture or lean conditions, it is advisable to add 3%–5% fatty oil to the compressor. In environments with high humidity, 10%~20% of fatty oils can be added; alternatively, a mixture of 5%~8% insoluble vegetable oils, hypoallergenic fats, or animal fats can be used to prevent liquid washes from breaking down the oil film formed by the precipitates. For sulfur-containing gases, SAE30 heavy-duty engine oil is the best choice. For engines and compressors as well as other equipment, the same lubricating oil used in the engines can be applied to protect the equipment from corrosion caused by sulfur-containing gases. At pressures above 7.5 Mpa, use SAE50 or SAE60 heavy-duty engine oil for sulfur-containing gases. 2. Hydrocarbon gases: These gases are miscible with mineral oils, thereby reducing the viscosity of the oil. Polymer hydrocarbon gases condense at lower pressures; therefore, humidity must be taken into account, and the requirements for lubricating oil are the same as those for natural gas. Gases such as propane, butane, ethylene, and butadiene mix easily with oil and can dilute the lubricant. To this end, a more viscous oil is needed to counter the effects of dilution and washing by gases and their condensates. Gases with particularly high requirements for compression purity, such as propane, are generally lubricated without oil. When oil lubrication is used, fatty lubricants or ethanol-fatty solution can be employed to provide the necessary lubrication. When compressing ethylene for high-pressure synthesis, to avoid contamination by lubricating oil that could affect the performance and purity of the product, pollution-free synthetic compressor oil or liquid paraffin should be used as the lubricant. For example, the lubricant used inside the two high-pressure and ultra-high-pressure compressors in the 300,000-ton ethylene plant imported from Japan is polyisobutylene with a molecular weight of 1500. Coke oven gas is mostly hydrogen and methane, and it is not pure; therefore, centrifugal compressors are generally used. If a reciprocating compressor is used, DAA100 or DAA150 air compressor oil can be selected. 3. Inert gases: Inert gases generally have no effect on lubricating oils; hydrogen and nitrogen can use the same compressor oil as that used for compressed dry air. For rare and precious gases such as argon, neon, and helium, it is often required that the gas be completely free of water and contain no oils at all. Therefore, membrane compressors are generally used, as there are no issues with cylinder lubrication. Both carbon dioxide and carbon monoxide are miscible with mineral oil, reducing the viscosity of the oil; if water is present, corrosive carbonic acid is also formed. Therefore, while maintaining dryness, lubricants with a higher viscosity grade should be selected to reduce the carryaway of oil and gas. The viscosity of the lubricating oil for compressed carbon dioxide media is generally not lower than that of SAE50 oil with additives; SAE40 oil is used at a pressure of 14 Mpa. Mixing carbon dioxide with oil causes gas pollution. When the gas is used for food processing or where contamination is not allowed, liquid wax remover or ethanol should be used as lubricants. Polyalpha-olefin synthetic oil can be used as a lubricant for new synthetic food-grade screw compressors. Polyalpha-olefin oil, after two rounds of hydrogenation, can meet food-grade requirements; it is non-toxic, does not irritate the skin or eyes, and complies with the specifications for industrial white oils. When using a centrifugal compressor to compress ammonia or syngas (which often contains large amounts of ammonia), the system must be kept dry to minimize contact between oil and the gas being transported. Because the presence of water causes ammonia to react with the acidic oxides of oil, resulting in the formation of precipitates. When selecting lubricating oil, it is best to use specialized ammonia-resistant turbine oil. 4. Chemically active gases: These gases interact with lubricating oils, and their use should be considered carefully. Chlorine and hydrogen chloride clouds? Can react with hydrocarbons under certain conditions; mineral oil cannot be used. For compressors handling such gases, oil-free lubricated compressors are commonly used; in some cases, concentrated sulfuric acid is used as a lubricant. The lubrication system and cylinders of the hydrogen sulfide compressor must be kept dry. In the presence of moisture, this gas is highly corrosive. The selection of lubricating oil is the same as when compressing moist air; it is recommended to use anti-oxidation and anti-rust turbine oil. Oxygen compressors typically use oil-free lubricated compressors. Both nitrous oxide and sulfur dioxide can mix with oil, thereby reducing its viscosity; therefore, lubricants with a higher viscosity grade should be used, such as oils of SAE40 or SAE50. When compressing nitrous oxide, heavy-duty engine oil containing dispersants must not be used, as the additives can react with any nitric acid that may form, resulting in excessive deposits. When sulfur dioxide is compressed, it acts as a selective solvent, helping to separate out any tar-like components present in the lubricant and causing them to precipitate. It is recommended to use rust- and oxidation-resistant turbine oil, and oil samples should be frequently checked for any sediment. Appendix: Selection of lubricants for different compression media
Table: Guidelines for selecting lubricants based on the type of compression medium

**Medium type and requirements for lubricants**
**Air**: Due to the presence of oxygen, the lubricant must have good anti-oxidation properties. Its flash point should be at least 40°C higher than the maximum exhaust temperature. Air compressor oil is suitable.
**Hydrogen and nitrogen**: No special requirements; air compressor oil can be used.
**Argon, neon, helium**: These gases are rare and valuable; it’s often required that there be absolutely no water or oil in them. Diaphragm compressors should be used, with N32 turbine oil or N32 machine oil applied inside the compressor chamber.
**Oxygen**: Can cause mineral oils to oxidize violently, potentially leading to explosions. Oil-free lubrication is preferred; alternatively, distilled water mixed with 6%–8% industrial glycerin may be used.
**Chlorine (hydrogen chloride)**: Under certain conditions, it reacts with hydrocarbons to form hydrogen chloride. Sulfuric acid or oil-free lubrication (dry lubrication), synthetic oils, or molybdenum disulfide can be used.
**Hydrogen sulfide**: The lubrication system must remain dry; moisture can dissolve gases and form acids that degrade lubricant performance. Anti-oxidation and anti-rust turbine oil or compressor oil is recommended.
**Carbon dioxide, carbon monoxide, nitric oxide**: These gases are miscible with oil, reducing its viscosity. Keeping the system dry helps prevent the formation of corrosive acids. Anti-oxidation and anti-rust turbine oil is suitable.
**Sulfur dioxide, ammonia**: If moisture is present, these substances can react with acidic oxides in the oil to form precipitates; they also react with acidic rust inhibitors to produce insoluble compounds. Anti-oxidation and anti-rust turbine oil is required.
**Synthetic hydrocarbons, natural gas**: Wet, oil-containing natural gas requires compressor oil; moist gas necessitates composite compressor oil. Condensate formed from oil can dilute the lubricant; air compressor oil is suitable.
**Ethylene**: In high-pressure ethylene compressors, to prevent oil from contaminating the product and affecting its quality, synthetic compressor oil (white oil) or liquid paraffin should be used instead of mineral oil.
**Propane**: Easily mixes with oil, lowering its viscosity; oil-free lubrication is recommended for high-purity propane. Ethanol-based lubricants with anti-rust and anti-oxidation properties are also suitable.
**Coke oven gas**: These gases do not significantly damage lubricants, but they tend to be dirty; if sulfur content is high, they may have a detrimental effect. Air compressor oil is suitable.
**Water gas, coal gas**: These contain many impurities that can contaminate lubricants. Filtered used air compressor oil can be reused. For cylinders, N68 or N100 cylinder oil or machine oil is suitable; for crankshafts, N46, N68, or N100 machine oil is recommended