CHEMICAL-FOAM CLEANING PROCESSES FOR THE CONTROL OF POWER-PLANT PARTICLE EROSION
Academic Article
Overview
Research
Identity
Additional Document Info
Other
View All
Overview
abstract
When exposed to hightemperature steam over extended time periods, heat transfer surfaces in power plants can be degraded by corrosive deposits of various oxidation products commonly known as scale. Solid particles can exfoliate from these surfaces, move downstream, and erode costly powergeneration equipment, including turbine valve stems, nozzle blocks, turbine diaphragms, turbine buckets etc. In addition, the heat transfer efficiency is substantially reduced. Such effects can be severe and can significantly increase capital expenses, fuel and operating costs unless abated by various techniques, among which the most common are mechanical and chemical cleaning. In this paper we analyse the use of foams as an alternative chemical cleaning method, and use a network of parallel tubes to stimulate key process and performance variables in chemical and foam cleaning. Among the process (or control) variables are: rheological properties of the foams, foam quality, inlet flow rates, network geometry, and injection strategy. Among the performance variables are: distributions of residence times, of flow, and of quality, pressure drops, and energy requirements. From this analysis we conclude that chemicalfoam cleaning offers technical as well as economic advantages over conventional cleaning methods. Copyright 1994 John Wiley & Sons, Ltd.