A deep understanding of the properties of steel is necessary in dealing with boilers. The most important properties of the boilers include: • Tensile strength • Hardness • Toughness • Fatigue strength • High-temperature characteristics Tensile Strength Tensile strength is the ability of a material to withstand the outward axial force or pull as opposed […]

Only the relevant principles of metallurgy of high-temperature materials used in boilers are discussed here. The most pertinent portions are alloying elements and heat treatment processes. A brief overview of classification of steels is given first. Classification Of Steels Steels can be classified broadly based on the criteria given below: 1. Percentage of carbon 2. […]

All the NPPs of the boiler, mainly the supporting structure and the plate work (flues, ducts, casing, hoppers, pent house, and bunkers), are made from structural steels. These steels are specified in the building codes. In a way there are no stringent requirements to be met as in the case of PP steels, except that […]

Boiler steels are of high-quality characterized by low carbon and high weldability, high consistency, definite high-temperature properties, and a long history of satisfactory usage. They are manufactured and tested to the specified codes. All the boiler steels should be procured only from code-approved manufacturers, and code recognition comes only after stringent and periodic verification regarding […]

A wide variety of both raw materials and components, besides auxiliary plant and equipment, are required to construct a boiler plant. Materials employed in boiler making can be broadly classified as shown in Table 5.1. Depending on the type of boiler and its scope, each of the three items in Table 5.1 con­tributes to —30 […]

Introduction A core boiler, excluding the firing equipment, is mainly built with several high-tempera — ture materials, namely steels and refractories, with structural steels used for support and sheet materials for air and gas transport. Refractories, heat-facing materials, are steadily being replaced by more steel for easier O&M. There is, however, a comeback of sorts […]

Carryover from a drum is the entrainment of contaminants in steam—solid, liquid, or vapors. It consists mostly of boiler water droplets with solids—both suspended and dis­solved. Silica is carried over in vaporous form. It is necessary to distinguish between steam purity and quality: • Purity is the amount of contaminant leaving the drum, measured in […]

Feed Water After being duly treated and deaerated, water gets pumped into the boiler as FW, which is heated in the ECON until it reaches the drum. Boilermakers and institutions responsible for water standards in various countries have evolved standards for FW and boiler water over the years, which, if maintained without any lapse during […]

Deaeration is the removal of dissolved gases, notably oxygen, from water. Dissolved gases cause many corrosion problems. Pitting caused by O2 (localized corrosion leading to pits) is particularly dangerous because the pits can lead to failure of parts under pressure, even if pitting is not widespread or not much material loss has taken place (Figure […]

The objective of water treatment, combining the external treatment and internal conditioning, in one word is cleanliness—cleanliness of the wetted parts. This, in turn, facilitates the production of clean steam, which keeps the boiler, piping, and turbine protected. External water treatment is done before water is fed into the boiler and is differentiated for a […]