Pressure Vessels

Title: Pressure Vessels

Author: David Chen

Steward: Fengqi You

Date Presented: January 13, 2014 /Date Revised: January 14, 2014

Introduction

Codes for pressure vessels can be found in the ASME Boiler and Pressure Vessel Code (ASME BPV code). While there is no formal definition, generally any closed vessel over 150 mm in diameter and that will experience a pressure difference of greater than 0.5 bar can be classified as pressure vessels. Types of equipment that can fit these descriptions include many reactors, separation columns, flash drums, heat exchangers, surge tanks, and storage vessels. Pressure vessels with a wall-thickness:diameter ratio of less than 1:10 can be classified as thin-walled, and the rest, thick-walled.(Towler)

Generally, chemical engineers will not be directly involved in detailed mechanical design of pressure vessels. This will be handled by mechanical engineers with experience in the field. However, chemical engineers will need to understand basic concepts of pressure vessel design in order to estimate costs and communicate specifications to those who will carry out the design (Towler/UOP).

Designs and Codes

Many countries have codes and standards concerning pressure vessels. The codes provide guidance on design, materials of construction, fabrication, inspection, and testing. In North America, the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME BPV Code) is used. There are twelve sections, and section VIII has three subdivisions. The sections are listed below. (Towler 3-5)

TABLE "American Society of Mechanical Engineers Boiler and Pressure Vessel Design Codes"

I Rules for construction of power boilers II Materials III Nuclear power plant components IV Rules for construction of heating boilers V Nondestructive examination VI Recommended rules for the care and operation of heating boilers VII Recommended guidelines for the care of power boilers VIII Rules for the construction of pressure vessels

     D1
     D2     Alternative rules
     D3     Alternative rules for the construction of high pressure vessels

IX Welding and brazing qualifications X Fiber-reinforced plastic vessels XI Rules for in service inspection of nuclear power plant components XII Rules for costruction and continued service of transport tanks