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Article
Publication date: 1 May 1962

H.J. Fortune

This paper is concerned with boilers and feed systems in power stations of relatively modern design—in general, those commissioned since 1945. The author considers a…

Abstract

This paper is concerned with boilers and feed systems in power stations of relatively modern design—in general, those commissioned since 1945. The author considers a number of inter‐related factors, commonly accepted as being influential in corrosion, in relation to boiler‐water and feed‐water control. These factors are: boiler design, insoluble boiler deposits, chemical conditions of boiler water and feed water, low‐load and off‐load water conditions and hide‐out.

Details

Anti-Corrosion Methods and Materials, vol. 9 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 October 1964

D. Kut

Corrosion problems in low‐pressure boiler plant systems arise chiefly in the following system components:— (i) Water Side of Boiler (Internal). (ii) Fire Side of Boiler

Abstract

Corrosion problems in low‐pressure boiler plant systems arise chiefly in the following system components:— (i) Water Side of Boiler (Internal). (ii) Fire Side of Boiler (External). (iii) Boiler Chimney. This article discusses corrosion problems relating to low‐pressure steam boilers operating at a maximum pressure of 200 psi, space heating boilers operating on closed water circuit and domestic hot water boilers operating on a direct tap‐water circuit.

Details

Anti-Corrosion Methods and Materials, vol. 11 no. 10
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 December 1972

F.E. Marsh

The inspection of steam plant by Engineer Surveyors, either in accordance with statutory regulations when out of service, under working conditions, or at times of trouble…

Abstract

The inspection of steam plant by Engineer Surveyors, either in accordance with statutory regulations when out of service, under working conditions, or at times of trouble, often reveals instances of corrosion. In the past, pitting and corrosion was a regular feature in practically all shell boilers, and not uncommon in watertube boilers, but in recent times this has become comparatively rare. This in itself is a tribute to the realisation, with the advent of the package boiler, of the necessity for boiler feedwater treatment and the maintenance of satisfactory conditions in boiler water in the lower pressure range.

Details

Anti-Corrosion Methods and Materials, vol. 19 no. 12
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 1 March 1977

C.A. Smith

Introduction Of the aspects of corrosion observed during the nineteenth century, those associated with boiler corrosion received the most systematic and exhaustive…

Abstract

Introduction Of the aspects of corrosion observed during the nineteenth century, those associated with boiler corrosion received the most systematic and exhaustive investigations. The main reason for this was that corrosion was one of the causes of boiler explosions and these caused many deaths during this period.

Details

Anti-Corrosion Methods and Materials, vol. 24 no. 3
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 9 January 2009

A. Saario and A. Oksanen

The purpose of this paper is to study the effect of a computational grid in computational fluid dynamics‐based mathematical modeling, focusing on but not limiting the…

Abstract

Purpose

The purpose of this paper is to study the effect of a computational grid in computational fluid dynamics‐based mathematical modeling, focusing on but not limiting the attention to industrial‐scale boilers.

Design/methodology/approach

A full boiler model is used to show the difficulties related to judging iteration and discretization errors in boiler modeling. Then, a single jet is studied in detail to determine the proper degree of local grid refinement required in the vicinity of jets in the full boiler model. Both a nonreactive axisymmetric jet exhausting into a quiescent atmosphere and a reactive jet exhausting into a crossfiow are studied.

Findings

Over two million computational cells are required for the grid‐independent solution for a single jet. Local grid refinement is shown to be a good option for improving the results consistently without an excessive increase in the number of computational cells. Using relatively coarse grids of tetrahedral cells with a finite‐volume‐based solver may cause serious errors in results, typically by overpredicting the jet spreading rate and underpredicting the mean axial centerline velocity. Relatively coarse grids of hexahedral cells are less prone to error in a case where a jet exhausts into a quiescent atmosphere. However, their performance deteriorates when a crossfiow is introduced. As assumed, the differences in the predicted reaction rate and species concentrations are significant in the reactive case. It is confirmed that the standard kε model tends to overpredict the axisymmetric jet spreading rate. The estimated inlet turbulence intensity is not among the most critical factors in modeling. Estimations of the axisymmetric jet centerline velocity from the analytical correlation may not coincide with the modeling results.

Practical implications

The error caused by the computational grid may easily dominate the errors caused by simplifying models used in industrial‐scale boiler modeling (turbulence, combustion, radiative heat transfer, etc.).

Originality/value

The present study deals with grid independency issues in industrial‐scale boiler modeling in a systematic and profound manner.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 29 April 2014

Wojciech P. Adamczyk, Pawel Kozolub, Gabriel Węcel and Arkadiusz Ryfa

The purpose of this paper is to show possible approaches which can be used for modeling complex flow phenomena caused by swirl burners combined with simulating coal…

Abstract

Purpose

The purpose of this paper is to show possible approaches which can be used for modeling complex flow phenomena caused by swirl burners combined with simulating coal combustion process using air- and oxy-combustion technologies. Additionally, the response of exist boiler working parameter on changing the oxidizer composition from air to a mixture of the oxygen and recirculated flue gases is investigated. Moreover, the heat transfer in the superheaters section of the boiler was taken into account by modeling of the heat exchange process between continuum phase and three stages of the steam superheaters.

Design/methodology/approach

An accurate solution of the flow field is required in order to predict combustion phenomena correctly for numerical simulations of the industrial pulverized coal (PC) boilers. Nevertheless, it is a very demanding task due to the complicated swirl burner construction and complex character of the flow. The presented simulations were performed using the discrete phase model for tracking particles and combustion phenomena in a dispersed phase, whereas the Eulerian approach was applied for the volatile combustion process modeling in a gaseous phase.

Findings

Applying the air- to oxy-combustion technology the temperature in the combustion chamber, decreased for investigated oxidizer compositions. This was caused by the higher heat capacity of flue gases which also influences on the level of the heat flux at the boiler walls. Simulations shows that increasing the O2 concentration to 30 percent of volume base in the oxidizer mixture provided the similar combustion conditions as those for the conventional air firing. Moreover, the evaluated results give a good overview of differences between approaches used for complex swirl burners simulations.

Practical implications

Nowadays, the numerical techniques such as computational fluid dynamic (CFD) can be seen as an useful engineering tool for design and processes optimization purposes. The application of the CFD gives a possibility to predict the combustion phenomena in a large industrial PC boiler and investigate the impact of changing the combustion technology from a conventional air firing to oxy-fuel combustion.

Originality/value

This paper gives good overview on existing technique, approaches used for modeling PC boiler equipped with complex swirl burners. Additionally, the novelty of this work is application of the heat exchanger model for predicting heat loses in convective section of the boiler. This usually is not taken into account during simulations. The reader can also find basic concept of oxy-combustion technology, and their impact on boiler working conditions.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 October 2003

Ton de Weijer and Wally Huijbregts

In a new build waste incinerator, the waste (refuse derived fuel) was burned on a discontinuous moving grate. Frequent furnace overpressure peaks occurred because of this…

Abstract

In a new build waste incinerator, the waste (refuse derived fuel) was burned on a discontinuous moving grate. Frequent furnace overpressure peaks occurred because of this firing method and as a result, flue gas and fly‐ash were pushed out of the boiler and into the building. During the plant start up period, a seal in a water‐feed pipeline broke, and a large amount of condensed steam was discharged into the boiler house. Shortly thereafter, very severe corrosion was noticed on the galvanised gangways, steel building components, the boiler aluminium sheeting and on processing lines. A theoretical study of the condensation of the flue gas indicated that sulphuric acid would condense before it reached the external aluminium sheeting and that under normal conditions, dry hydrochloric acid fumes would be removed by the boiler house ventilators. However, the steam leakage had caused the hydrochloric acid to be dissolved in the condensed water and that had resulted in the severe corrosion damage, which had become evident subsequently.

Details

Anti-Corrosion Methods and Materials, vol. 50 no. 5
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 4 September 2017

Amita Rani, Niraj Bala and C.M. Gupta

Hot corrosion is the major degradation mechanism of failure of boiler and gas turbine components. The present work aims to investigate the hot corrosion resistance of…

Abstract

Purpose

Hot corrosion is the major degradation mechanism of failure of boiler and gas turbine components. The present work aims to investigate the hot corrosion resistance of detonation gun sprayed (D-gun) Cr2O3-75 per cent Al2O3 ceramic coating on ASTM-SA210-A1 boiler steel.

Design/methodology/approach

The coating exhibits nearly uniform, adherent and dense microstructure with porosity less than 0.8 per cent. Thermogravimetry technique is used to study the high temperature hot corrosion behavior of bare and coated boiler steel in molten salt environment (Na2SO4-60 per cent V2O5) at high temperature 900°C for 50 cycles. The corrosion products are analyzed by using X-ray diffraction, scanning electron microscopy (SEM) and field emission scanning electron microscope/energy-dispersive analysis (EDAX) to reveal their microstructural and compositional features for elucidating the corrosion mechanisms.

Findings

During investigations, it was found that the Cr2O3-75 per cent Al2O3 coating on Grade A-1 boiler steel is found to be very effective in decreasing the corrosion rate in the molten salt environment at 900°C. The coating has shown lesser weight gains along with better adhesiveness of the oxide scales with the substrate till the end of the experiment. Thus, coatings serve as an effective diffusion barrier to preclude the diffusion of oxygen from the environment into the substrate boiler steel.

Research limitations/implications

Therefore, it is concluded that the better hot corrosion resistance of the coating is due to the formation of desirable microstructural features such as very low porosity, uniform fine grains and the flat splat structures in the coating; as compared to the bare substrate under cyclic conditions.

Practical implications

This research is useful for coal-fired boilers and other power plant boilers.

Social implications

This research is useful for power generation plants.

Originality/value

There is no reported literature on hot corrosion behavior of Cr2O3-75 per cent Al2O3 coating deposited on the selected substrates by D-gun spray technique. The present work has been focused to study the influence of the Cr2O3-75 per cent Al2O3 coating developed with D-gun spraying technique on high temperature corrosion behavior of ASTM-SA210-A-1 boiler steel in an aggressive environment of Na2SO4-60 per cent V2O5 molten salt at 900°C under cyclic conditions.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 26 August 2014

Wai Ming To, Hon Kit Hung and Wai Leung Chung

The purpose of this paper is to evaluate the energy, economic and environmental performance of commercial water heating systems in Hong Kong special administrative region…

Abstract

Purpose

The purpose of this paper is to evaluate the energy, economic and environmental performance of commercial water heating systems in Hong Kong special administrative region (SAR), China.

Design/methodology/approach

The research team contacted 50 facilities managers in Hong Kong, and 16 of them agreed to participate in this territorial-wide survey. The overall efficiency of different water heating systems was determined through measurements of inlet water temperatures, outlet steam/water properties, the amount of steam/water produced and the amount of energy consumed. The cost effectiveness and the amount of greenhouse gases produced per megajoule (MJ) output were also determined.

Findings

Results show that electric water heating systems had the highest mean overall efficiency, followed by gas- and oil-fired systems. However, the difference between the mean overall efficiency of the three types of water heating systems was not statistically significant, as the systems had been inspected and maintained regularly. Oil-fired systems were found to be the most cost-effective when taking fuel prices into consideration. Environmental analysis showed that gas-fired systems produced the least amount of greenhouse gases per MJ output.

Originality/value

Water heating is one of the major uses of energy in buildings. Hence, the efficiency of a water heating system can have a significant effect on the overall performance of a building. This paper not only provides insight on the energy performance but it also evaluates the economic and environmental performance of water heating systems.

Details

Journal of Facilities Management, vol. 12 no. 4
Type: Research Article
ISSN: 1472-5967

Keywords

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Article
Publication date: 25 May 2020

Suyog Subhash Patil and Anand K. Bewoor

India's textile industries play a vital role in the Indian economy. These industries consume the highest thermal energy (steam power). The demand of the steam in process…

Abstract

Purpose

India's textile industries play a vital role in the Indian economy. These industries consume the highest thermal energy (steam power). The demand of the steam in process industries is increasing rapidly, and this demand can be met by increasing the capacity utilization of steam boilers. The purpose of this paper is to present a new approach for reliability analysis by expert judgment method.

Design/methodology/approach

A lack of adequate life data is one of the biggest challenge in the reliability analysis of mechanical systems. This research provides an expert judgment approach for assessing the boiler's reliability characteristics. For this purpose, opinions of experts on time to failure and time to repair data were elicited in the form of statistical distributions. In this work, reliability analysis of the boiler system is carried out by expert judgment method and by using best-fit failure model. The system reliability along with preventive maintenance intervals of all components is also evaluated.

Findings

It is observed that the reliability analysis results obtained by expert judgment method and best-fit failure model method indicate that there are no significant differences. Therefore, in case when insufficient data are available, the expert judgment method can be effectively used. The analysis shows that the feedwater tank, feedwater pump, supply water temperature sensor, strainer, return water temperature sensor, condensate filter, mechanical dust collector, coal crusher and fusible plug are identified as critical components from a reliability perspective, and preventive maintenance strategy is suggested for these components.

Originality/value

In this research paper, a system reliability model by the expert judgment method is developed, and it can be effectively used where insufficient failure data are available. This paper is useful for the comparative evaluation of reliability characteristics of a boiler system by expert judgment method and best-fit failure model method.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 1
Type: Research Article
ISSN: 0265-671X

Keywords

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