The use of rupture discs in chemical engineering design and their functions; the installation location of rupture discs

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This post was last edited by goldliyang on 2016-9-22 at 14:45. Function of blast discs: to prevent excessive pressure in pressure vessels, pipelines, or other enclosed spaces, serving as a safety release mechanism. Parameters that need to be determined for a burst disc: equipment name, normal operating pressure of the equipment, design pressure of the equipment, normal operating temperature of the equipment, medium inside the equipment, corrosivity, negative pressure during operation of the equipment, and discharge diameter. The rupture disc is used in conjunction with a holder, which serves to fix the rupture disc and maintain its sealing properties; a holder should be used when the designed burst pressure is greater than 1 kilogram. If a blast pressure that is relatively low is designed, it may not be necessary to use a clamp; however, the user must provide the drawings for the mounting flange or the flange standards, in order to prevent a mismatch between the dimensions of the burst disc and those of the flange. Disc material: nickel, austenitic stainless steel, Monel, Hastelloy, graphite. A burst disc safety device is a non-self-closing emergency pressure relief device driven by a pressure difference. A safety relief device suitable for use in pressure vessels, pipelines, or other enclosed spaces to prevent overpressure or excessive vacuum. The set rupture pressure of the burst disc should be higher than the normal operating pressure but lower than the design pressure of the equipment; it must also be above 1 atmosphere in order to create a pressure difference on both sides of the burst disc. Reasons for premature rupture of the burst disc: The corrosiveness of the medium causes the rupture pressure of the burst disc to be lower than the set value, while unstable temperature of the pressure vessel leads to changes in the rupture pressure of the burst disc. Points to consider when selecting a rupture disc model: 1. The operating temperature of the rupture disc material; 2. The corrosiveness of the working medium towards the material – anti-corrosion measures such as applying a fluoroplastic coating or adding a fluoroplastic protective layer can be used as a corrosion barrier; 3. When the rupture disc is used in series with a safety valve, it is necessary to choose a model that does not produce fragments after pressure release. The combined use of a burst disc and a safety valve is generally employed in conditions with strict requirements; using a safety valve alone is not safe, especially in environments involving flammable, explosive, or toxic substances. By combining a burst disc and a safety valve, sealing can be achieved, and once the burst disc activates, the safety valve can take over to ensure continued operation on a temporary basis. The rupture disc and the clamp are installed in between the flanges; gaskets can be used between the flanges and the clamp to provide sealing. These gaskets are usually made of PTFE or copper, and no gaskets are allowed to be used between the rupture disc and the clamp. As complementary devices, clamps and rupture discs are required for pressure vessels over 1 kilogram in weight when a rupture disc is used as a pressure relief device. The materials used for these clamps are usually carbon steel and stainless steel; in cases where corrosion is a concern, clamps with PTFE components at the inlet side and carbon steel or stainless steel components at the outlet side can be chosen. When the temperature exceeds 260°C, other materials suitable for such operating conditions can be considered for the clamps. Operating conditions for rupture discs: 1. When the pressure in a pressure vessel rises sharply due to a reaction, the safety valve does not have time to open; the high sensitivity of the rupture disc allows it to meet the requirements for pressure relief in such situations. 2. The medium in pressure vessels tends to crystallize and has a certain viscosity, which can easily cause blockages in safety valves, preventing them from fulfilling their pressure-relief function; in such cases, rupture discs should be used as pressure-relief devices. 3. When the medium in the pressure vessel is flammable, explosive, toxic, or highly corrosive, using a safety valve results in high costs; moreover, specific requirements are imposed on the material of the valve core, and its sealing performance may not meet the required standards. In such cases, an explosion vent is the best choice.