1. What is design ?

The act of working out the form of  some thing (as by marking a sketch  or out line or plan )

  1. What is design interpretation?

Design interpretation means to interpret or under stand the drawing.

  1. Introduction to pressure vessel

Several types of equipment, which are used in the chemical, petrochemical fertilizer industries are described bellow.

  • Pressure vessel
  • Storages vessel
  • Distillation column
  • Heat exchanger
  • Evaporator
  • Reactor, etc.

In all this equipment pressure vessel is a basic and generally used in all     above types of industries.Pressure vessel are usually spherical or cylindrical with domed ends. They are provide with openings or nozzles with facilities for marking  threaded or flanged joints. Various methods are used for supporting the vessel.

  1. Definition of vessel

A container or structural envelope in which material are processed, or stored.

  1. Definition of pressure vessel

A container or structural envelope in which material are processed, treated, or stored which has been designed to operate at pressure above 15 Psi are knows as pressure vessel.

  1. Which codes used make design of pressure vessel?

Various code reference which is used  for design and construction of pressure vessel are as below.

  • ASME sec viii div-1
  • IS 2825
  • BIS 5500
  1. Why designing is required for  pressure vessel?

The selection of the types of vessel based primarily upon the fictional service of the  vessel. The functional service requirements impose certain operating conditions such as temperature, pressure, dimensional limitation and various loads.

If the vessel is not designed properly the vessel may be fail in service. The design of most structure is based on formulas. Formula may be used form any relative code/standards so the value derived form that formula is reliable.

  1. Why necessary design of pressure vessel?

If vessel is not designed properly’ the vessel may be fail in service.

Failure may be occur in one or more manners such by the plastic deformation resulting form excessive stress, or by elastic instability.

  1. What parameter affect the failure of vessel?

Failure may also result form corrosion, wear or fatigue. Design of the vessel to protect against such as failures involve the consideration of these factors and the physical properties of the materials.

If the vessel is not properly designed then chances of failure is more because we don’t know what is the maximum operating pressure and temperature. We don’t know about maximum load, pressure or temperature carrying capacities of the vessel.

10 . Stresses in pressure vessel

Pressure vessel are subjected to various loading which exert stresses of  different intensities in the vessel components.

The various stresses, which are generating during working and service time, are tabulated below.

API 580 :

Risk-Based Inspection was initiated and managed by the American Petroleum Institute (API) within the refining and petrochemical industry:

  • API RP 580 Risk-Based Inspection RBI
  • API RP 581 Risk-Based Inspection RBI Technology(Only Introduction Not for Examinations)

API RP 580 introduces the principles and presents minimum general guidelines for developing a RBI program for fixed equipment and piping. API RP 581 provides quantitative RBI methods to establish an inspection program. Together, these two documents comprise a widely-recognized standard for industry-accepted RBI practices.

This API training course helps attendees understand and use RBI Risk Based Inspection technology, develop a program, and learn which RBI Risk Based Inspection  procedures and working processes comply with industry standards.

The calculation of risk in API RBI Risk Based Inspection involves the determination of a Probability of Failure combined with the Consequence of Failure. Failure in API RBI is defined as a loss of containment from the pressure boundary resulting in leakage to the atmosphere or rupture of a pressurized component. As damage accumulates in a pressurized component during in-service operation the risk increases. At some point, a risk tolerance or risk target is exceeded and a more effective inspection is recommended to better quantify the damage state of the component. The inspection action itself does not reduce the risk; however, it does reduce uncertainty thereby allowing better quantification of the damage present. API Risk Based Inspection RBI technology systematically factors risk into inspection decision-making, helping identify areas of vulnerability by confirming equipment condition, identifying damage mechanisms and rates, and predicting Probability of Failure. The outputs of a Risk Based Inspection RBI study help plant personnel make more informed decisions and target inspection dollars where they are needed most and more effectively manage reliability.

 

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