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Facilities and Operating Sources
Published in Rengasamy Kasinathan, Environmental Compliance Guide for Facility Managers and Engineers, 2023
A fire-tube boiler utilizes hot gases from combustion passing through boiler tubes that are surrounded by water. After several passes through subsequent tubes, the hot gases exit the flue stack. The combustion heat in the tubes then heats the water through conduction, convection, and radiation. This heat transfer creates the steam, which is the final product of the boiler and can then be used for the various purposes we discussed.
Understanding and Managing Boilers
Published in Barney L. Capehart, Wayne C. Turner, William J. Kennedy, Guide to Energy Management, 2020
Barney L. Capehart, Wayne C. Turner, William J. Kennedy
A boiler is either a fire tube boiler—with tubes containing flame and surrounded by water—or a water tube boiler—with tubes containing water surrounded by flame. The basic operation of a fire tube boiler is shown in Figure 9-1. Fuel and air are combined in a burner, go through tubes and heat up water, and leave through a flue. The water is brought into the boiler, surrounds the tubes containing the fire from the burner, rises to the top under pressure, and leaves the boiler for use in industrial processes or to generate electricity.
Lexicon
Published in Samuel C. Sugarman, HVAC Fundamentals, 2020
fire tube boiler:: (Boiler) A fire tube boiler has hot flue gases from the combustion chamber (the chamber or space where combustion takes place) flowing through tubes (fire tubes) and out the boiler stack. The fire tubes are surrounded by water. Heat from the hot gases transfers through the walls of the tubes and heats the water. Fire tube boilers may be further classified as externally fired, meaning that the fire is entirely external to the boiler, or they may be classified as internally fired, in which case, the fire is enclosed entirely within the steel shell of the boiler. Two other classifications of fire tube boilers are wet-back or dry-back. This refers to the compartment at the end of the combustion chamber. This compartment is used as an insulating chamber so that heat from the combustion chamber, which can be several thousand degrees, does not reach the boiler’s steel jacket. If the compartment is filled with water it is known as a wet-back boiler, if the chamber contains only air it is called a dry-back.
Effect of paddy drying methods on the performance of rice mills in Bangladesh
Published in Drying Technology, 2023
Sahabuddin Ahamed, Chayan Kumer Saha, Surajit Sarkar, Md. Monjurul Alam
Steam produced in the fire tube boiler of automatic and semi-automatic rice mills was used in the steaming operation of paddy and for generating hot air through heat exchanger. During drying of parboiled paddy, average hot air temperature at heat exchanger, inlet duct, drying zone, reserve zone, and paddy temperature at elevator position were found 85 °C, 72 °C, 52 °C, 37 °C, and 35 °C, respectively (Figure 5a). Whereas, average temperature at blower, inlet duct, drying zone, reserve zone, and paddy temperature at elevator position were found 70 °C, 55 °C, 45 °C, 38 °C, and 36 °C, respectively for aromatic paddy (Figure 5b). Temperature of hot air at drying zone was found about 25–33 °C lower than blower/heat exchanger section. 15 °C reduction of hot air temperature was also found during the end period of drying for both parboiled and aromatic paddy to elevate rice recovery. Though hotter dry air was used for parboiled paddy but the ultimate paddy temperature was almost same in both cases. Parboiled paddy is soaked and steamed before drying which creates lose moisture layer outside the grain kernel. Higher temperature was used for quickly removing the exterior moisture of parboiled paddy. On the other hand, white rice obtained from aromatic paddy is more precious than that of parboiled paddy. Hence, comparatively lower hot air temperature was maintained for aromatic paddy to avoid high percentage of broken over milling. So, if the temperature of hot air can be controlled in one dryer, then parboiled and aromatic paddy will also be dried in that dryer.
Reducing Energy Losses of Steam Boilers Caused by Blowdown with Using the FMEA Method
Published in Smart Science, 2021
Ceyda Kocabaş, Ahmet Fevzi Savaş
Putra and Purba [20] analyzed the frequent failures in the boiler of a steam power plant. They created cause and effect diagram to find out boiler failures and their effects and then calculated risk priority numbers of these. Mariajayaprakash and Senthilvelan [21] identified the failures which frequently occurred in the cogeneration boiler and gave the solution to minimize these failures by using the Ishikawa diagram and failure mode and effect analysis. Afefy [22] performed failure mode and effect analysis (FMEA) for a fire-tube boiler in the process steam plant. He examined malfunctions in various boiler equipment and their effects. Igboanugo et al. [23] carried out the FMEA for critical components of the boiler system. They highlighted the various ways by which the system can fail and the impact of such failures on the entire boiler system performance. Erajati et al. [24] researched equipment risks on the boiler using the FMEA method and obtained 3 top events as the high-risk category. Kumar et al. [25] applied the FMEA method to the water tubes in the boilers. They determined that there are many critical failure modes in the boiler and focused on failures occurring in the water tubes and then, they calculated the risk priority coefficients.