Introduction

Chapters 4 and 5 discuss the concepts for determining the diameter and length of two-phase and three-phase vertical and horizontal separators. This chapter addresses the selection of design pressure rating and wall thickness of pressure vessels. It also presents a procedure for estimating vessel weight and includes some examples of design details.

The purpose of this chapter is to present an overview of simple concepts of mechanical design of pressure vessels that must be understood by a project engineer specifying and purchasing this equipment. Most pressure vessels used in the oil and gas industry are designed and inspected according to the American Society of Mechanical Engineers' Boiler and Pressure Vessel Code (ASME code). Because the ASME code contains much more detail than can be covered in a single chapter of a general textbook such as this one, the project engineer should have access to a copy of the ASME code and should become familiar with its general contents. In particular, Section VIII of the code, "Pressure Vessels," is particularly important. Countries that do not use the ASME code have similar documents and requirements. The procedures used in this chapter that refer specifically to the ASME code are generally applicable in other countries but should be checked against the applicable code.

In U.S. federal waters and the majority of countries with oil and gas operations, all pressure vessels must be designed and inspected in accordance with the ASME code. In some countries, however, there is no such requirement. It is...