00962 Improved steels for advanced power plant applications

00962 Improved steels for advanced power plant applications

08 Steam raising (boiler operation/design) potassium in these deposits is derived from K-Al-Si-rich fly ash particles and the remaining is in the fo...

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Steam raising (boiler operation/design)

potassium in these deposits is derived from K-Al-Si-rich fly ash particles and the remaining is in the form of KLSOI. This paper provides a review of Danish experiences with high-temperature ash deposit formation in a number of full-scale utility boilers, for example, Haslev CHP (23 MW,h). all straw-fired grate-boilers; Grend CHP (80 MW,h), a coal-straw co-fired circulating fluidized bed boiler: and the Mldtkraft-Studstrup Power Station. Unit I(380 MWth).

B&W’s IR-CFB coal-fired boiler operating 00/00955 experiences Kavidass, S. er ul. Proc. .4rm. Irrf. fittsh~r@ Cocrl Cortf.. 1998, IS. 103% 1043. Updated in this paper is the operating experience of two Babcock & Wilcox (B&WI coal-fired, internal recirculation circulating fluidized-bed (IR-CFB) boilers: The first boiler is and is designed for 35 MW, output for cogeneration application, utilizing high sulfur, low ash Illinois coal, and is located at Southern Illinois University (SIU) in Carbondale, Illinois, U.S.A. The second boiler can he found at Kanoria Chems. & Industries Ltd. (KCIL) in Renukoot, India and is designed for 81 MW, output for captive power requirements, firing high ash, low sulfur coal. Thermax B&W (TBW) Ltd. supplied this boiler. Discussed in this paper are the various aspects of the two IR-CFB boilers’ design features, performance and overall operating.

Combustion characteristics and pollution minimum 00100956 technology for VR (vacuum residue) fired boiler Toshimitsu. I JSME Int. .I., Ser. B, 1998, 41, (4). 1055-1060. This paper dkscrihes an experimental study on the combustion of extra heavy oil, which was performed using a cylindrical test furnace. In order to use VR as a fuel in boilers a number of serious problems must he overcome first. These include the corrosion of metal materials at high- and lowtemperatures, plus the need to meet environmental regulations, which means low NO, and a low unburned carbon ratio in the exhaust gas. In the study discussed in this paper, a firing test was carried out to analyse the basic characteristics of vacuum residue combustion. It was possible to ascertain from the test results that stable ignition performance was achieved, and both NO, emission and the unburned carbon ratio in exhaust gas were at the same level as for bituminous coal combustion. In addition, the reactivity and the carbon structure of the sampled soot and char were chemically examined and the rate of reaction with oxygen was calculated.

Combustion issues of low reactive solid fuels in 00100957 boilers combustion chambers Efimov. N. N. Izv. Vyssh. Uchebn. Zaved., Sev.-Kavk. Reg., Tekh. Nauki, 1998, (I), 54-58. (In Russian) It is reported that highly reactive fuels, such as brown coal and gas coal, with 2-3 times less air than theoretically required and particle size 2-3 times less than low reactive fuels, do not cause problems during their combustion in boiler combustion chambers. As ash content increases, the oxygen demand of the fuel particles and stoichiometric fuel-to-air ratio decrease. For the spray combustion of solid low reactivity fuels, the arrangement of various vertical streams within the boiler chamber and other devices that are related to the steady state motion of the medium are important.

Concentrations of hydrocarbons (f&H,) and PAH in 00100958 flue gas emitted from water heaters and steam boilers Kapitaniak, J. and Gruzinski, R. Zesz. Nauk.-Politech. Lodz., Inz. Chem. Procesowa, 1998, (23), 33-40. (In Polish) Presented in this paper is a method to detect for the presence hydrocarbons and policyclic aromatic hydrocarbons in flue gases from water heaters and steam boilers. The experimental results obtained using this method for the analysis of flue gases from coal-fired, oil-fired and gas-fired boilers are discussed.

Development and operation results of low NO,-high 00/00959 efficiency coal fired new ClJF boiler Kimishiro, T. ef a/. JSME Int. J., Ser. B, 1998, 41, (4), 1050-1054. As a result of recent demands for effective use of energy and increased awareness of environmental protection, a new circular ultra firing (CUF) boiler has been developed by MHI. The new boiler is capable of ensuring a low NO, emission and can burn coal at a stable rate at a low air ratio. In the CUF type boiler, its burner is installed at the four surrounding walls and the fuel and air are injected slightly downwards to he fired while they are encouraged to swirl over the entire furnace. This boiler type has always been orientated towards combustion of hard-to-burn coals such as anthracite, because of its excellence in fuel ignition performance. In the newly developed CUF boiler, those features were adopted towards low NO, and high efficiency. In order to decrease the level of NO, further, optimum conditions of the burner location and the fuel injection direction were found using a 1115 scale cold model test, which made it possible to achieve coal firing at a lower NO,. Based on these results, a CUF boiler of evaporation capacity 350 t/h was constructed and this boiler has been successfully operated.


Fuel and Energy Abstracts

March 2000

00100960 Development of a pressurized internally circulating fluidized-bed boiler Miyoshi, N. et al. Ebara Jiho, 1999. 182, 25-3. (In Japanese) Ehara’s Sodegaura Plant has recently developed and tested a pressurized. internally circulating fluidized-bed boiler (PICFB). Combustion studies were conducted using different types of coal under various conditions. This boiler proved to he beneficial in many ways. it is easy to control and operate, it has a minimal environment. and it is capable of using various types of coal as fuel. The heat generated hy the boiler can he used effectively for the generation of power, and chemical constituents in the exhaust gas can he applied for material recycling. This boiler, as well a\ its scaled-up model, the A-PICFB. is described in this paper. 00100961 Devices for automatic control of gas, liquid and solid fuels underfiring in industrial thermal boilers Tarasevich, V. N. Prom. Teplotekh., 1997, 19. (6). 98-105. (In Russian) Devices for the automatic control of gas-mazut and solid fuels under-firing in power plants are discussed in this article. A discussion on the chemical and mechanical under-firing of fuels is also included. 00100962 Improved steels for advanced power plant applications Yang, 2. and Gibbons, T. B. PVP (Am. Sot. Mech. Eng.). 1998, 374. (Fatigue, Environmental Factors, and New Materials), 371-375. In order to improve the efficiency while maintaining a competitive price in terms of specific costs of power plants burning pulverized coal. considerable effort is being made worldwide to improve the performance of ferritic steels for pressure part applications in utility boilers. The drive to maximize the use of ferritic materials arises because of the relatively high cost ot austenitic alloys and their large coefficient of thermal expansion as well as the advantage of avoiding the problems of dissimilar metal welds. There has been a major improvement in performance of the modified YCrlMo material (Grade 91) resulting from the addition of elements such as tungsten, cobalt, boron and nitrogen to optimized 9-124 chromium compositions. In the present paper the current situation is reviewed, and creep data presented to illustrate the performance of the various materials. A key point is that oxidation resistance has sometimes been sacrificed in order to obtain improved mechanical properties at high temperature, and data on oxidation in steam environments are also presented. A feature of the development of high strength ferritic steels has heen the need to extrapolate creep data from short-term tests in order to predict ctrength characteristics in conditions typical of service. Traditionally the LarsonMiller parameter has been used to predict creep hehaviour although it is well known that this method is not entirely reliable. Accordingly some effort has been made to develop improved predictive methods using models based on the deformation and fracture hehaviour. 00100963 Reburning technologies for the control of nitrogen oxides emissions from coal-fired boilers Clean Coal Technology, 1999, Topical report 14, l-28. The Clean Coal Technology (CCT) Demonstration Program is a government and industry co-funded effort to demonstrate a new generation of innovative coal utilization processes in a series of ‘showcase’ facilities built across the country. These projects are carried out on a scale sufficiently large to demonstrate commercial worthiness and to generate data for design, construction, operation and technical/economic evaluation of fullscale commercial applications. The goal of the CCT Program is to furnish the US energy marketplace with a number of advanced, more efficient coalbased technologies meeting strict environmental standards. These technologies will mitigate the economic and environmental impediments that limit the full utilization of coal as a continuing viable energy resource. This report discusses three CCT rehurning projects: coal rehurning for cyclone boiler NO, control; gas rehurning-low-NO, burners; and micronized coal reburning. 00100964 Surface treatment of boiler steel pipes for wear resistance Tsumida, Y. Jpn. Kokai Tokkyo Koho JP II 29,840 [99 29,X49]. (Cl. C23C12102). 2 Feh 1999, Appl. Y7/186,128, 11 Jul 1997, 4 pp. (In Japanese) Steel pipes, used in fluidized bed boilers and coal fired boilers. are treated in a furnace with a silica particle fluidized bed at -SO0 Oxide coatings are formed on the outer surfaces when air is fed into the furnace. 00100965 Techno-economic analysis of NO, reduction technologies in p.f. boilers McCahey, S. er al. Fuel, 1999, 78, (14), 1771-1778. The impact of NO, reduction technologies upon a supercritical coal fired p.f. power station has been investigated using the ECLIPSE process simulator. Technical, environmental and economic assessments were performed, based upon a model of the Amer 9 Power Station at Geertruidenherg, the Netherlands. Selective catalytic reduction (s.c.r.) achieves the largest reduction in NO, emissions to helow SO mg/N m’. but at an additional electricity cost of 0.21 p/kWh, over the base case. The additional cost for coal-over-coal rehurning is 0.03 p/kWh, reducing NO, emissions to below 200 mg/N m’. Only high unburnt carbon losses or high priced rehurn coal justify the use of a coal micronizer. Natural gas-over-coal reburning requires an unrealizable natural gas price of f0.98/GJ to compete with coal-over-coal rehurning. Gas prices between fl.76/GJ and fl.93iGJ are required for it to compete with s.c.r.