Bursting disc

FIG. 26-22 Multireactor knockout (K-O) drum/catch tank a) plan view of reactors connected to horizontal containment vessel (h) back-to-back bursting disc assembly (c) elevation of self-supporting vessel (d) elevation of horizontal vessel on roof of building (e) elevation of horizontal vessel on side of building. 

The precious metals are many times the cost of the base metals and, therefore, are limited to specialized applications or to those in which process conditions are highly demanding (e.g., where conditions are too corrosive for base metals and temperatures too high for plastics where base metal contamination must be avoided, as in the food and pharmaceutical industries or where plastics cannot be used because of heat transfer requirements and for special applications such as bursting discs in pressure vessels). The physical and mechanical properties of precious metals and their alloys used in process plants are given in Table 3.38. 

Integrated and welded bursting disc with signal unit and glued gasket, optional aseptic, sanitary, or sterile design... 

Pumps, valves, pipes, bursting discs, human errors, and other miscellaneous items... 

The book contains, in alphabetical order, failure rates, event rates and probabilities, and descriptive information which has been collected since 1970 in the course of doing risk and reliability assessments. Twenty appendices contain results of surveys on bursting discs, pipes, valves, relief valves, pump failures and information on human error, international fire losses, and blast effects. 

SAIC s data bank focuses on pumps, valves, and other common major components, but due to its depth has also been applied to studies on items such as strainers and bursting discs. Access is based on the scope of work and the estimated labor hours required to search and sort the data. 

Bursting discs are the simplest and most certain form of protection against the effect of over-pressure in a closed system. They cannot fail to operate. 

The protection of vessels containing corrosive materials presents a special problem for the selection of bursting discs—a rapid rate of corrosion can lead to a high frequency of failures. In addition, the creep of a metal disc when under tension at elevated temperatures would tend to weaken it and result in premature failure. 

Bursting discs may be fabricated of gold, silver, platinum or palladium. The recommended maximum temperatures for continuous use are 80 C for gold, 150 C for silver, 300 C for palladium and 450 C for platinum. Figure 6.6 gives bursting pressure/disc thickness data for these metals and for aluminium and nickel. 

To prevent overpressure within a compressor, a relief valve or bursting disc is often fitted between the inlet and discharge connections. 

This is one of the simplest applications of the flow of a compressible fluid and it can be used to illustrate many of the features of the process. In practical terms, it is highly relevant to the design of relief valves or bursting discs which are often incorporated into pressurised systems in order to protect the equipment and personnel from dangers which may arise if the equipment is subjected to pressures in excess of design values. In many cases it is necessary to vent gases evolved in a chemical reaction. 

A further hazard exists when compressed air jets are used to clean machine components in workplaces flying particles have caused injury and blindness. Cylinders may fail if overpressurized or weakened by the application of heat. Liquefied gases, e.g. butane or propane, respond more rapidly to heat than the permanent gases such as nitrogen or oxygen. Cylinders are normally protected by pressure relief valves, fusible plugs or bursting discs. 

Figure 5.107. The polymerisation reactor with cooling and bursting disc.

The ISIM program RUN with KV = 0 represents operation of the reactor under zero venting (V = 0) conditions, i.e., the bursting disc remains closed. With KV > 0 ( 100 - 1000) the program simulates the performance under emergency venting conditions. The program runs stably until the user interacts with HOLD and causes the coolant failure to occur with HOLD, VAL FC = 0 and GO. 

Bursting discs thin discs of material that are designed and manufactured to fail at a predetermined pressure, giving a full bore opening for flow. 

Bursting discs and relief valves are proprietary items and the vendors should be consulted when selecting suitable types and sizes. 

Askquith, W. and Lavery, K. (1990) Proc. Ind. Jl. (Sept.) 15. Bursting discs—the vital element in relief. AIChemE (1987) Guidelines for Hazard Evaluation Procedures (Center for Chemical Process Safety, American Institute of Chemical Engineers, New York). 

Mathews, T. (1984) Chem. Engr., London No. 406 (Aug.-Sept.) 21. Bursting discs for over-pressure protection. 

Specification for bursting discs and bursting disc devices. 

Interaction is extremely exothermic, and under confinement in an autoclave the internal temperature and pressure exceeded 100°C and 135 bar, causing failure of the bursting disc. The product of interaction is dimethylhydroxymethylenimmo-nium bromide, and the explosive decomposition may have involved formation of A-bromodnuethylamine, carbon monoxide and hydrogen bromide. 

When aqueous sodium hydroxide was added to a mixture of the chloride and alcohol at 28°C instead of the normal 5°C, a rapidly accelerating reaction led to rupture of the bursting disc and a gasket, and subsequently to a flash-fire and explosion. 

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