Introduction

The welded equipment that is to be discussed under this heading is used for the transport and processing of hydrocarbons and for raising steam in power stations. The common feature of such plant is the containment of fluids at elevated pressure and at temperatures that may be either higher or lower than normal room temperature. Food and pharmaceutical processing, where the problems are somewhat different, will not be considered.

Steam is used both in hydrocarbon processing and in power generation, and the plant required for raising steam is much the same in both cases. However power plant has its own special problems and will therefore be dealt with separately.

For petroleum refineries and petrochemical plant the feedstock and energy source is either liquid hydrocarbons or natural gas, so it is logical to start with discussing the pipelines that are used for conveying these fluids from the wells to the process area.