Understanding pulverised coal, biomass and waste combustion – A brief overview

Abstract

Pulverised coal (PC) firing has been the dominant technology for generating power in utility boilers for almost a century. During this period, boiler designs have evolved through an accumulating collection of knowledge that has led to many empirical relationships that still guide current and future design directions to some degree. In the late 1940s the developed nations began to undertake coal research based on scientific principles to ensure the most efficient use of the primary energy resource represented by coal. As the body of scientific knowledge on the physics and chemistry of coal combustion grew, it was used to direct the improvements to efficiency required and, later, the control of pollutants produced during the combustion of coal. This involves not only the control of emissions of particulates, SOx and oxides of nitrogen but also of trace elements, polycyclic aromatic hydrocarbons and, importantly, CO2.There have been a number of significant developments in the coal-fired power generation sector including cofiring with secondary fuels, particularly biomass and waste, and the development of radically different combustion systems (for example, oxyfuel) to meet carbon capture and storage requirements. Each of these developments has impacted upon the way in which PC-fired boilers are configured and operated and further complicated an already complex combustion environment.This paper outlines the developments in PC combustion and the new techniques that have been developed to enhance our understanding of the processes involved. The paper is based on a comprehensive IEA Clean Coal Centre study “Understanding pulverised coal, biomass and waste combustion”. Ian Barnes, CCC/205 ISBN 978-92-9029-525-9, September 2012.