Search Results for fired boilers

The presence of certain impurities in coal and oil is responsible for the majority of fireside corrosion experienced in utility boilers. In coal, the primary impurities are sulfur, alkali metals, and chlorine. The most detrimental impurities in fuel oil are vanadium, sodium, sulfur, and chlorine. This article describes the two categories of fireside corrosion based on location in the furnace: waterwall corrosion in the lower furnace and fuel ash corrosion of superheaters and reheaters in the upper furnace. It discusses prevention methods, including changes to operating parameters and application of protective cladding or coatings.

This article provides a discussion on the mechanisms of wear and their interactions with gaseous corrosion. The wear mechanisms include abrasive, erosive, fretting, and sliding. The measurement of degradation on combustion walls in coal-fired boilers is discussed. The article concludes with information on the common coating techniques used for wear-corrosion control.

Both nondestructive testing (NDT) and nondestructive evaluation (NDE) use noninvasive measurement techniques to gain information about defects and various properties of materials, components, and structures. This article begins with a discussion on the historical development of quantitative measurement techniques, evaluation reliability, and quantitative interpretation of nondestructive inspection methods. The common nondestructive evaluation methods, along with their uses and limitations, are summarized in a table. The article conceptually illustrates the interplay of NDE and fracture mechanics in the damage tolerant approach. It concludes with information on pressure vessel applications that can be separated into three protocols used by military nuclear power, commercial nuclear power, and non-nuclear pressure vessels and/or fired boilers.

The use of renewable energy has grown strongly in all end-use sectors such as power, heat, and transport. This article describes thermal spray applications that improve efficiency, lower maintenance costs, and prolong operational life in the renewable energy technologies, including wind power, hydro power, biomass and biofuels, solar energy, and fuel cells.

Fusible alloys, eutectic and noneutectic, include a group of binary, ternary, quaternary, and quinary alloys containing bismuth, lead, tin, cadmium, and indium that melt at relatively low temperatures. This article describes the composition and mechanical properties of these alloys and lists the values of their composition and melting temperatures.

Failures in boilers and other equipment taking place in power plants that use steam as the working fluid are discussed in this article. The discussion is mainly concerned with failures in Rankine cycle systems that use fossil fuels as the primary heat source. The general procedure and techniques followed in failure investigation of boilers and related equipment are discussed. The article is framed with an objective to provide systematic information on various damage mechanisms leading to the failure of boiler tubes, headers, and drums, supplemented by representative case studies for a greater understanding of the respective damage mechanism.

This article explains the main types and characteristic causes of failures in boilers and other equipment in stationary and marine power plants that use steam as the working fluid with examples. It focuses on the distinctive features of each type that enable the failure analyst to determine the cause and suggest corrective action. The causes of failures include tube rupture, corrosion or scaling, fatigue, erosion, and stress-corrosion cracking. The article also describes the procedures for conducting a failure analysis.

This article describes the corrosion modes in a waste-to-energy boiler. It discusses the corrosion protection and alloy performance with an emphasis on two main areas of the boiler: furnace water walls and super heaters.

This article briefly describes water and steam chemistry, which influence the effect of corrosion in boilers. The appropriate control measures to prevent corrosion in boilers are also presented. The article provides a discussion on the common causes of fluid-side corrosion such as flow-accelerated corrosion, oxygen pitting, chelant corrosion, caustic corrosion, acid corrosion, organic corrosion, phosphate corrosion, hydrogen damage, and corrosion-assisted cracking.

High-temperature exposure of materials occurs in many applications such as power plants (coal, oil, natural gas, and nuclear), land-based gas turbine and diesel engines, gas turbine engines for aircraft, marine gas turbine engines for shipboard use, waste incineration, high-temperature fuel cells, and missile components. This article discusses high-temperature corrosion in boilers, diesel engines, gas turbines, and waste incinerators. Boilers are affected by stress rupture failures, waterside corrosion failures, fireside corrosion failures, and environmental cracking failures. Contamination of combustion fuel in diesel engines can cause high-temperature corrosion. Gas turbine engines are affected by hot corrosion. Refractory-lined incinerators and alloy-lined incinerators are discussed. The article provides case studies for each component failure.

Porcelain enamels are glass coatings applied primarily to products or parts made of sheet steel, cast iron, or aluminum to improve appearance and to protect the metal surface. This article provides information on the types and properties of the porcelain enamels and frits for porcelain enameling. It describes the corrosion resistance of the porcelain enamels in a variety of environments. Evaluation of properties of the porcelain-enameled products to control specifications and quality of porcelain-enamel coatings is also reviewed. The article contains a table that lists the specific test methods for evaluating various properties of porcelain enamels.

This article describes the specific features and mechanisms of oxidation in thermal spray coatings. It discusses the two forms of hot corrosion in sulfur-containing combustion, namely high-temperature hot corrosion and low-temperature hot corrosion. The article reviews the behavior of corrosion-resistant coatings in boilers. The effects of high-temperature corrosion in waste incinerators are detailed. The article also examines the effects of erosion-corrosion in fluidized bed combustion boilers.