[Q&A Question 210] 2017.07.29
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【Q&A Question 210】July 29, 2017: What is the medium used for cleaning the various oil pipelines inside the facility? The reference answers will be visible after responding; points are awarded by identifying the key points. (Unless otherwise specified, all questions and answers are based on hydrogenation units.) ) 1. Air purging is not allowed for oil pipelines with a flash point below 60°C, to prevent the mixture of oil vapor and air from forming an explosive mixture. 2. Crude oil pipelines are generally purged with hot water; if welding is required on the pipeline, the water in the vent pipe must be drained first, followed by purging with steam and compressed air. 3. Pipelines for residue oil, heavy oil, lubricating oil feedstocks, and heavy deasphalted oil are generally cleaned using steam and compressed air. 4. The finished lubricants, additives, and light diesel are purged using dehydrated compressed air or nitrogen in the pipelines. 5. Pipelines for gasoline, solvent oil, kerosene, jet fuel, aromatics, and light polluted oil should be purged with nitrogen; water can also be used for this purpose. If hot work is required on the pipeline, it should be purged with steam. 6. Fuel gas, low-pressure vent gas, liquefied petroleum gas, hydrogen, etc. should be vented and then purged with nitrogen or steam. 7. Acid and alkali pipelines should be purged with dehydrated compressed air or nitrogen. 8. For pipelines transporting hot asphalt, hot residue oil, etc., with a transport temperature above 120°C, light diesel should be used to flush the pipeline first, followed by purging it with steam and compressed air. Steam and compressed air should not enter the hot oil tank. 9. Underground pipelines with an asphalt anti-corrosion coating shall not be purged with steam. To prevent the asphalt from softening due to heat and damaging the anti-corrosion layer. Scoring criteria: 2 Wealth points for incorrect responses; *incomplete* answers earn 3–8 points. 10 Wealth points for correct answers, provided along with a detailed explanation; responses that are correct but lack sufficient details earn 15–20 Wealth points. Please score according to these criteria. Note: If there are editing records after answering, only those who participated will be credited points. For continuous malicious spamming, 2 points will be deducted each time, with no upper limit. Pure numbers, pure emojis, or random letters that have nothing to do with the answer are all considered malicious spamming; points will start to be deducted after three warnings. 2017 Q&A Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657793-1-1.html 2017 Daily Question Summary Thread (updates have begun) http://bbs.hcbbs.com/thread-1657794-1-1.html 2016 Q&A Summary Thread (updates completed) http://bbs.hcbbs.com/thread-1597792-1-1.html Petrochemical Sector – “Creative Ideas for Energy Saving” Campaign (the second phase is in full swing) http://bbs.hcbbs.com/thread-1666758-1-1.html (Source: Haichuan Chemical Industry Forum Website)
When the purging medium comes into contact with the medium to be purged, no intense vaporization, chemical reactions, or the formation of hazardous substances should occur； Floating roof or internal floating roof tanks should not have oil pumped into them using steam or other gases. Hot water is generally used as the scanning medium
1. Operating natural gas pipelines: Remove water accumulation, light oils, methane hydrates, iron oxide, carbide dust, carbon disulfide, hydrogen sulfide, and other corrosive substances from within the pipelines, in order to reduce the corrosive damage caused by these substances to the inner walls of the pipes. 2. Operating crude oil pipelines: Removing sludge, wax buildup, and scale inside the pipelines aims to reduce backpressure during oil transportation, lower friction losses, and decrease the oil transport temperature. 3. Chemical materials and edible oil pipelines: Clean pipelines containing polymeric materials, and isolate different pipeline media to enable the transportation of multiple products through a single pipeline.
Generally, it is steam, nitrogen, and water, depending on the specific type of oil.
1. Crude oil pipelines are generally purged with hot water; if welding is required on the pipeline, the water inside it must first be drained, followed by purging with steam and compressed air. 2. Pipelines for residue oil, heavy oil, lubricating oil feedstocks, and heavy deasphalted oil are generally cleaned using steam and compressed air. 3. Finished lubricants, additives, and light diesel are purged using dehydrated compressed air or nitrogen in the pipelines. 4. Pipelines for gasoline, solvent oil, kerosene, jet fuel, aromatics, and light polluted oil should be purged with nitrogen; water flushing can also be used. If hot work is required on the pipeline, it should be purged with steam. 5. Fuel gas, low-pressure vent gas, liquefied petroleum gas, hydrogen, etc. should be vented and then purged with nitrogen or steam. 6. Acid and alkali pipelines should be purged with dehydrated compressed air or nitrogen. 7. For pipelines transporting hot asphalt, hot residue oil, etc., at temperatures above 120°C, light diesel should be used as a topping agent before the pipelines are purged with steam and compressed air. Steam and compressed air should not enter the hot oil tank.
1. Crude oil pipelines are generally purged with hot water; if welding is required on the pipeline, the water inside it must first be drained, followed by purging with steam and compressed air. 2. Pipelines for residue oil, heavy oil, lubricating oil feedstocks, and heavy deasphalted oil are generally cleaned using steam and compressed air. 3. Finished lubricants, additives, and light diesel are purged using dehydrated compressed air or nitrogen in the pipelines. 4. Pipelines for gasoline, solvent oil, kerosene, jet fuel, aromatics, and light polluted oil should be purged with nitrogen; water flushing can also be used. If hot work is required on the pipeline, it should be purged with steam. 5. Fuel gas, low-pressure vent gas, liquefied petroleum gas, hydrogen, etc. should be vented and then purged with nitrogen or steam. 6. Acid and alkali pipelines should be purged with dehydrated compressed air or nitrogen. 7. For pipelines transporting hot asphalt, hot residue oil, etc., at temperatures above 120°C, light diesel should be used as a topping agent before the pipelines are purged with steam and compressed air. Steam and compressed air should not enter the hot oil tank.
1. Crude oil pipelines are generally purged with hot water; if welding is required on the pipeline, the water in the vent line must be drained first, followed by purging with steam and compressed air. 2. Residue, heavy oil, lubricating oil feedstocks, and heavy deasphalted oil pipelines are generally purged using steam and compressed air. 3. The finished lubricants, additives, and light diesel are purged using dehydrated compressed air or nitrogen in the pipelines. 4. Pipelines for gasoline, solvent oil, kerosene, jet fuel, aromatics, and light contaminated oil should be purged with nitrogen; water flushing can also be used.