Coal-based thermal power plants play a major role in the welfare of many nations and the overall global economy. This chapter describes the basic equipment requirements and operating principles of thermal power plants, particularly subcritical, supercritical, and ultra-supercritical types.

Boilers are engineered systems designed to convert the chemical energy in fuel into heat to generate hot water or steam. This chapter describes boiler applications and types, including firetube boilers, watertube boilers, electric boilers, packaged boilers, fluidized bed combustion boilers, oil- and gas-fired boilers, waste heat boilers, and black liquor recovery boilers. It also describes the operation and working principle of utility or power plant boilers, covering conventional subcritical and advanced supercritical types.

Boilers are often classified based on the maximum operating temperature and pressure for which they are designed. Classifications, in ascending order, are subcritical, supercritical, ultra-supercritical, and to advanced ultra-supercritical. At each higher operating point comes greater efficiency, as well as greater demand on construction materials. This chapter discusses the primary requirements for boiler tube materials, including oxidation and corrosion resistance, fatigue strength, thermal conductivity, and the ability to resist creep and rupture. It also provides information on various steels and alloys, covering cost, engineering specifications, and ease of use.

This chapter discusses material-related problems associated with coal-fired burners. It explains how high temperatures affect heat-absorbing surfaces in furnace combustion areas and in the convection pass of superheaters and reheaters. It describes how low-NOx combustion technology, intended to reduce NOx emissions, accelerates tube wall wastage. It also covers circumferential cracking in furnace waterwalls, thermal fatigue cracking induced by waterlances and water cannons, superheater-reheater corrosion, and erosion in fluidized-bed boilers.

Increasing the efficiency of power plants by operating at higher temperatures and pressures and adding a double-reheat feature comes at the expense of shortened lifetimes for critical components. This chapter provides an overview of the material-related problems associated with advanced steam plants and their respective solutions. The discussion covers the selection of materials on a component-specific basis for boilers as well as steam turbines.

Nickel and nickel-base alloys are specified for many applications, such as oil and gas production, power generation, and chemical processing, because of their resistance to stress-corrosion cracking (SCC). Under certain conditions, however, SCC can be a concern. This chapter describes the types of environments and stress loads where nickel-base alloys are most susceptible to SCC. It begins with a review of the physical metallurgy of nickel alloys, focusing on the role of carbides and intermetallic phases. It then explains how SCC occurs in the presence of halides (such as chlorides, bromides, iodides, and fluorides), sulfur-bearing compounds (such as H2S and sulfur-oxyanions), high-temperature and supercritical water, and caustics (such as NaOH), while accounting for temperature, composition, microstructure, properties, environmental contaminants, and other factors. The chapter also discusses the effects of hydrogen embrittlement and provides information on test methods.

This chapter describes the metallurgy, composition, and properties of steels and other alloys. It provides information on the atomic structure of metals, the nature of alloy phases, and the mechanisms involved in phase transformations, including time-temperature effects and the role of diffusion, nucleation, and growth. It also discusses alloying, heat treating, and defect formation and briefly covers condenser tube materials.