Waste Steam Recovery

Abstract

An examination has been made of the recovery of waste steam by three techniques: direct heat exchange to process, mechanical compression, and thermocompression. Near atmospheric steam sources were considered, but the techniques developed are equally applicable to other sources of steam. The interaction of the recovery system with the plant's steam/power system has been included. Typical operating economics have been prepared. It was found that the profitability of most recovery schemes is generally dependent on the techniques used, the existing steam/power system, and the relative costs of steam and power. However, there will always be site-specific factors to consider. It is shown that direct heat exchange and thermocompression will always yield an energy profit when interacting with PRVs in the powerhouse.

A set of typical comparisons between the three recovery techniques, interacting with various powerhouse and plant steam system configurations, is presented. A brief outline of the analysis techniques needed to prepare the comparison is also shown. Only operating costs are examined; capital costs are so size - and site-specific as to be impossible to generalize. The operating cost savings may be used to give an indication of investment potential.