In what situations must emergency shut-off valves be installed?

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This post was last edited by shiwendong on 2018-1-25 at 21:12. First of all, let’s restate the function of the emergency shut-off valve EBV. (1) Generally, the valves mentioned in our DCS systems, whether they are control valves or on/off valves, are primarily designed to ensure normal production operations. The requirements regarding the fault locations of valves such as FC, FO, and FL are also established based on the principles of intrinsically safe design, in order to prevent disruptions in production. (2) Valves in SIS generally refer to the Final elements in SIF; they are designed to help reduce risks in the event of a hazard. The SILs specified in SIF also impose corresponding requirements on valves, aiming to address the probability of failure where the valves fail to perform their safety functions (opening or closing) when needed. (3) The emergency shut-off valve EBV is used in cases of fire here; it is necessary to isolate the process medium in order to prevent the fire from spreading further and reduce losses. So the question is, in what situations is it necessary to install an emergency shut-off valve EBV? Let’s first take a look at what the standards say. (1) The document \"Specifications for the Selection and Design of Emergency Shutoff Valves for Liquefied Hydrocarbon Spheres in Sinopec – 2011\" stipulates that emergency shutoff valves shall be installed on the inlet and outlet pipelines of liquefied hydrocarbon spheres (liquefied hydrocarbons refer to hydrocarbon liquids with a vapor pressure greater than 0.1 MPa at 15°C, excluding liquefied natural gas). (2) The \"Code for Fire Protection Design of Petrochemical Enterprises\" (GB 50160-2008) specifies as follows: 6.3.14 Full-pressure liquefied hydrocarbon storage tanks should be equipped with a secondary dehydration system that includes anti-freezing measures, and an emergency shut-off valve should be installed at the base of the tank. Paragraph 6.4.1 requires that railway loading and unloading facilities for flammable liquids shall comply with the following provisions: 4 An easily operable emergency shut-off valve shall be installed on the inlet pipeline for flammable liquids (except lubricating oils), at a distance of more than 10 m from the edge of the loading dock. Paragraph 6.4.2 requires that automobile loading and unloading stations for flammable liquids shall comply with the following provisions: 5 When there are no buffer tanks in the station, emergency shut-off valves that are easy to operate shall be installed on the loading and unloading pipelines at a distance of more than 10 meters from the vehicle loading/unloading cranes. Article 6.4.3 requires that the loading and unloading facilities for liquefied hydrocarbons on railways and roads shall comply with the following provisions: An emergency shut-off valve that is easy to operate shall be installed on the loading and unloading pipelines at a distance of more than 10 m from the loading/unloading nozzles. Paragraph 6.4.4 requires that combustible liquid terminals and liquefied hydrocarbon terminals comply with the following provisions: 4 Emergency shut-off valves that are easy to operate shall be installed on the loading and unloading pipelines at a distance of 20 meters from the berth or at the shore. Paragraph 7.2.15 requires that the extraction piping for liquefied hydrocarbon equipment shall be equipped with a shut-off valve located near the base of the equipment; when the volume of the liquefied hydrocarbon equipment exceeds 50 m3 and the distance between it and its extraction pump is less than 15 meters, such shut-off valve must be a remotely operated valve with a manual function. To prevent the material from not being cut off in the event of a fire in downstream equipment that is directly connected to the light. (3) API 2510, \"Design and Construction of Liquefied Petroleum Gas (LPG) Facilities\", specifies that isolation valves on liquefied hydrocarbon pipelines should be located as close as possible to the tank, preferably installed on the flange of the tank wall nozzles. For ease of operation and maintenance, the installation location of the cut-off valve should be easily accessible. When the volume of a liquefied hydrocarbon tank exceeds approximately 38 m3 (10,000 gallons), all isolation valves located on pipes below the highest liquid level in the tank should be able to close automatically or via remote control within 15 minutes of a fire breaking out. The control system for the shut-off valve should be protected against fire, and the shut-off valve should be operable manually. (4) Chapter 3 of API RP2001 \"Fire Protection in Refineries\" explicitly requires that \"emergency shut-off valves shall be installed at the connections below the liquid level in containers holding large quantities of flammable liquids.\" (5) Chapter 7 of API RP553 \"Control Valves in Refineries\" specifies the basic principles for installing emergency shut-off valves (EBVs) on equipment such as compressors, pumps, heaters, and vessels. After reviewing the specifications, let’s take a look at the principles for setting up the emergency shut-off valve EBV In line with foreign regulatory requirements as well as design examples from large engineering companies both at home and abroad, it is generally required that emergency shut-off valves EBV be installed on the process pipelines at the outlet (or inlet) adjacent to equipment with a high fire hazard, and be capable of fully meeting the requirements for isolation operations in order to prevent uncontrolled release of flammable or toxic materials. Since the design of the emergency shut-off valve EBV is closely related to fire prevention in the facility, from both process and safety perspectives, it is necessary to first define high-fire-hazard equipment and fire-hazard areas in order to determine where emergency shut-off valves EBV need to be installed. The aforementioned equipment with a high fire hazard includes: containers for light components with a volume greater than 7.571 m3 (2,000 gallons) ； LPG storage tanks larger than 15.5 m3 (4,000 gallons) ； Containers or heat exchangers in which the temperature of the flammable liquid inside exceeds 315°C or has already reached the auto-ignition temperature ； Pumps capable of transporting flammable liquids such as hydrocarbons at a rate of over 45 m3/h ； Combustible gas compressors with a power greater than 150 kW ； Heating furnace for heating flammable liquids through a furnace tube ； Hydrocarbon reactors with an internal pressure greater than 3.45 MPa and a exothermic reaction mode, etc. Fire hazard areas include: the area within 9 m horizontally or 12 m vertically from high-fire-hazard equipment ； Areas within 9 m of spherical tanks containing flammable media, etc. The installation of emergency isolation valves is closely related to the size of the equipment volume, the type of medium, temperature, as well as the power and capacity of the pumps. The practices of domestic and international engineering companies are as follows: The criteria established by Company A are: (1) LPG storage tanks with a capacity greater than 8 m3; (2) Storage tanks for hydrocarbons (or other flammable substances) with a capacity greater than 8 m3, where the temperature of the substance is higher than its auto-ignition temperature or higher than 250°C; (3) Hydrocarbon (or other flammable substance) storage tanks with a capacity greater than 16 m3; (4) Large-scale units with a power output exceeding 150 kW. Principles for setting up Company B: (1) The temperature of the process medium inside the pump (which is flammable) is higher than its normal boiling point, the total amount stored at the inlet and outlet exceeds 450 kg, and the potential leakage rate of the pump’s sealing system is above 450 kg/min (if the dispersion model developed by the detailed design contractor shows that the leakage rate will not exceed the lower explosive limit even when it is 1300 kg, then this value for the leakage rate can be increased appropriately) ； (2) The temperature of the process medium inside the pump (which is flammable) is above its auto-ignition point, and the total amount stored at the inlet and outlet exceeds 450 kg ； The above leakage calculations assume a catastrophic failure of the pump sealing system; if leak-free pumps are used, the isolation system can be eliminated. At present, the emergency isolation systems installed in most domestic projects are basically similar to those adopted by Company A. It is precisely because the requirements for emergency shut-off valves in the standards differ from those for ordinary valves, and it is not possible to clearly define what constitutes an emergency shut-off valve, that disputes arise between the process engineering team and the automation team during the design process, leading to an awkward situation in which neither the design firm nor the client will yield. Feels good; sharing it with everyone. It was found on the internet, and I don’t know its original source, so I can’t indicate it