scope:

This publication addresses the operation of the reboilers of air separation plants. It contains a summary of current knowledge and industrial practices used in their safe application. It specifically applies to the main reboiler and oxygen product reboilers in which the oxygen concentration is above 75% in the liquid phase. Its guiding principles may be used for other reboilers within air separation plants, including auxiliary vaporizers, guard adsorber vaporizers, argon condensers, and the main reboilers in nitrogen generators.

Reboilers feeding krypton/xenon columns and the krypton/xenon distillation system are excluded from the scope of this publication. These systems and their methods of dealing with hydrocarbon accumulation vary widely. Reboiler operation and safety for plants with these units should be discussed with the supplier on a plant-specific basis.

Purpose

The purpose of this publication is to describe the design and operating practices that shall be followed in the reboiler sections of cryogenic air separation plants. In particular, the potential hazard introduced by hydrocarbons or other contaminants that might be present in the ambient atmosphere is addressed. The thought is that this has been the prime cause of the majority of reported reboiler incidents.

This publication is based upon the experimental data, operating experience, and design practices of major producers and operators of air separation plants. It is recognized that legislation or regulation can impose more stringent requirements for plant design and operation.