ABSTRACT
A pulverized coal (PC) fired boiler is a complex chemical reactor consisting of many complex processes, such as gas-solid flows, combustion, heat transfer (conduction, convection, and radiation) and phase change, all in one piece of equipment. Key features of PC fired boilers were discussed in Chapter 1. In order to design and operate PC fired boilers in the best possible way, several design variables and operating parameters must be optimized. Some of these include
• Size and configuration of the boiler • Design, number, and location of the burners • Characteristics of the fuel (coal) • Particle size/size distribution of the pulverized fuel • Extent of excess air to be used • Feed temperature (of air and coal particles)
Design and operating engineers are interested in maximizing the thermal efficiency of boilers by eliminating or minimizing unburned carbon in fly ash and bottom ash. Internal heat exchangers and the fluid dynamics of the furnace must be designed to maximize efficiency on the one hand and minimize downtime of the boiler on the other hand (often required for cleaning deposits on internal heat exchangers and water walls of the boiler). Through years of design and operating experience, significant expertise and guidelines have been developed by practicing engineers. However, as discussed in Chapter 1, it is always desirable to complement this accumulated experience with computational models and simulation tools. Computational models allow design and operating engineers to gain better understanding and carry out virtual experiments to evaluate new and innovative ideas. The inherent complexities of PC fired boilers, however, make the task of computational modeling these boilers quite complex and nontrivial. This book essentially discusses the details of computational modeling of PC fired boilers. This chapter discusses the overall approach toward developing computational models of PC fired boilers.
