Pressure tank, ethylene oxide, design, safety facilities, safety valve, drain pipe
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This post was last edited by applepet1984 on 2010-12-17 at 17:33. I would like to ask about the safety design for ethylene oxide storage tanks in cold northern regions: Such tanks should be equipped with two safety valves, each of which should have a burst disc in front of it – one that is normally open and another that is closed (used for maintenance purposes). The inlet of the burst discs should be sealed with nitrogen to prevent self-polymerization-induced blockages, while the outlet of the safety valves should be connected to a nitrogen pipeline to dilute the concentration of ethylene oxide. The design pressure for ethylene oxide storage tanks is generally 1 MPa. A double valve should be installed on the dehydration pipeline of such tanks. It is advisable to use a secondary dehydration system with anti-freezing measures (i.e., an additional intermediate dehydration container). Storage tanks need to be equipped with water injection systems to prevent leaks of liquefied hydrocarbons. In the event that freezing occurs in winter and causes the first valve in the liquefied hydrocarbon pipeline to crack, a hydrocarbon pump can be used to inject water into the tank and drain water from the leak site, thereby reducing gas leakage. The water pipe is semi-fixed to the liquefied hydrocarbon. I’m not sure if there are any issues or shortcomings with these safety measures.
Add a leak detector to monitor at any time
This post was last edited by Happy Tease on 2010-12-18 at 14:46. The water injection system should have a separate water pump, with pressure higher than the maximum pressure in the storage tank. Dehydration systems must be installed in cold regions
5.3 Ethylene oxide and ethylene glycol (ethylene oxidation method) 5.3.1 The ethylene oxidation reaction system must be equipped with alarm and automatic shutdown interlock devices as well as emergency shutdown control measures. The oxygen and ethylene concentrations in the gas mixture entering the reactor, as well as the oxygen content in the exhaust gas leaving the reactor, should be monitored continuously. 5.3.2 The oxygen injection tube of the oxygen mixer shall be equipped with automatic nitrogen filling and cleaning measures during shutdown. Storage facilities for nitrogen used for automatic cleaning should be provided. 5.3.3 The ethylene oxide purification tower shall be equipped with tower pressure alarms, automatic shutdown, and emergency shutdown facilities. 5.3.4 Pumps for transporting ethylene oxide shall have measures to prevent idling and no-flow operation, as well as interlock devices for over-temperature alarms of the liquid inside the pump and automatic shutdown. 5.3.5 Sprinkler protection facilities shall be installed near the dynamic seal of ethylene oxide or ethylene oxide aqueous solution pumps. 5.3.6 Gaseous ethylene oxide should only be transported over short distances within the plant via pipelines. When liquid ethylene oxide is transported between adjacent units via pipelines, it should be insulated with chilled brine, and there must be no gas space within the pipelines. 5.3.7 The inlet of the ethylene oxide safety valve shall be continuously filled with nitrogen, and the vent pipe of the safety valve shall be equipped with a nitrogen filling connection. 5.3.8 The gas space of the ethylene oxide storage tank shall be filled with nitrogen, and a water spray system shall be installed outside the tank. 5.3.9 Ethylene oxide should not be filled within the equipment area of the unit or in its vicinity. The filling area should be equipped with facilities for filling tank trucks or cylinders with nitrogen, spraying water for protection, and flushing the floor. 5.3.10 Storage tanks for ethylene oxide shall be located separately, with dikes installed around them.
Thank you! I ignored the issue of ethylene oxide being miscible with water, so a dehydration unit and a water injection system are not required. However, the emergency pressure relief measures for ethylene oxide storage tanks, that is, the installation of safety valves and blast discs, remain unclear. Should an ethylene oxide storage tank be equipped with two safety valves? A burst disc should be installed in front of each safety valve; the inlet of the burst disc should be sealed with nitrogen to prevent self-aggregation-induced blockages, and a nitrogen pipeline should be connected to the outlet of the safety valves to dilute the concentration of ethylene oxide. Are the two safety valves installed separately (with each valve’s pipeline connected to the tank independently), or through a tee? Are valves installed on the inlet pipes of the safety valve, one normally open and one normally closed (for maintenance purposes)?
Reply to 3# HappyFun: Ethylene oxide is miscible with water in any ratio; to separate the two, distillation is the only method. What is the purpose of dehydration?
Reply to 6# Zhu Hongbin: SORRY, I made a mistake; I need to learn from you*:L :L