Pressure vessels classification

Chemical plant equipment—including tanks, pressure vessels, piping, rotating equipment, vent systems, and safety instrumentation—should be identified and categorized into different degrees of hazard potential. Classification systems could be simple or very complex. A complex system could be a matrix of increasing severity ratings on one axis and the... 

The intent of the mechanical integrity section of the OSHA Process Safety Law is to prevent or reduce catastrophic releases. [1] An equipment classification system is a requirement of the law. Earlier in the chapter, a simple system involving three classes was previously defined. Here are the highlights of that section specifically for pressure vessels and storage tanks. 

Pressure vessel test (L) Classification test for FFL class 5 Dangerous Goods (Self—reactive substances)... 

Table 1 gives an overview of high pressure processes currently employed and their classification for batch / continuous service. The types of pressure vessels fabricated for these design conditions can be seen in table 2. 

The stress limits for the canister vessel are in accordance with the ASME Boiler and Pressure Vessel Code, Section III, Subsection NB (ASME, Subsection NB). The stress limits for fhe canister basket are in accordance with the ASME Boiler and Pressure Vessel Code, Section III, Subsection NG (ASME, Subsection NG). In both cases, stresses are identified by the type of stress, that is, bending, shear, and so on, and the classification of the stress, that is, primary, secondary, and so on. 

IS 2825-1969 for unfired pressure vessels provides the foUowing classification... 

Standards on pressure vessels will provide valuable further detail. The definition of specified (including registered) plant, which includes boilers and pressure vessels, m vary between jurisdictions. Generally, however, this classification includes ary designated plant, with exclusions for particular pressure vessels and boilers with specific capacities. 

The stress classifications for various parts of a pressure vessel are indicated in Table 4.1 and are reproduced from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Sections III and VIII. It can be observed that the membrane stress is considered primary for mechanical loads. Eor a number of geometries and loading situations, the bending stress is considered secondary. The bending stress is considered primary when the net section experiences the applied bending moment. 

Classification of pressure vessels according to method of construction... 

Table 8.2 visualizes a classification of supercritical processes regarding the solid or liquid state of the feed material to be treated. Solids are processed batchtvise in high-pressure vessels, tvhereas liquids are moved continuously via countercurrent columns either as a falling film or as a droplet spray. Most important is the formation of a phase boundary bettveen the feed material and the supercritical fiuid in order to... 

A runaway reaction occurs when an exothermic system becomes uncontrollable. The reaction leads to a rapid increase in the temperature and pressure, which if not relieved can rupture the containing vessel. A runaway reaction occurs because the rate of reaction, and therefore the rate of heat generation, increases exponentially with temperature. In contrast, the rate of cooling increases only linearly with temperature. Once the rate of heat generation exceeds available cooling, the rate of temperature increase becomes progressively faster. Runaway reactions nearly always result in two-phase flow reliefs. In reactor venting, reactions essentially fall into three classifications ... 

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