Advanced pressurized fluidized bed combustion technology

09 Combustion 02lOO556 Additive for enhancing coal-burning efficiency Na, X. Faming Zhuanli Shenqing Gongkai Shuomingshu CN 1,227,256 (Cl. ClOL9/10), 1 Sep 1999, Appl. 98,107,116, 25 Feb 1998. 5. (In Chinese) The additive comprises smoke suppressor selected from Tween-60 and Fez03 10-20, desulphurizer selected from MnCOs and CaO O-20, combustion promoter selected from KNOs, NaNOs, and NaCl 20-40, KMn04 oxidant 10-15, activator selected from sodium dodecylbenzene sulphonate, Na hexametaphosphate, NaTPOd, and their mixture 10-20, and leavening agent selected from MgO, NaCl, and vermiculite O-10%. 02lOO557 Advanced pressurized fluidized bed combustion technology Ikeda, N. e/ al. Sekitan Riyo Gijutsu Kaigi Koenshu, 1999, 9, 3&M. (In Japanese) The advanced pressurized fluidized bed combustion (A-PFBC) system in which a partial oxidation furnace is added and the inlet temperature to the gas turbine is increased in order to improve power plant efficiency is described. Plan for a 15 t/d process development unit (PDU) study of the system is introduced, including the study of the reaction and operation properties of the combined system of partial oxidation furnace, desulphurization furnace, and oxidation furnace. 02/00558 An atmospheric pressure, fluidired bed combustion system burning high-chlorine coals in the convection section Liu, K. er al. Corrosion (Houston), 2000, 56, (3) 298-306. The possibility of fireside corrosion in power plant boiler components is always a major concern when the fuels include high-sulphur and high-chlorine coals (or refuse waste). Sulphur and chloride product may play important roles especially in fireside corrosion in atmospheric pressure, fluidized bed combustion (AFBC) systems, caused by the capture of sulphur and chlorine by limestone used as bed material in the combustor, and the resulting deposition of sulphur- or chlorine-rich compounds onto metallic surfaces. Results were reported from tests in a O.l-MW,s AFBC system where 1000-h test burns were conducted using two coals with widely differing chlorine levels, and limestone was used as the sulphur sorbent. Coupons of three stainless steels (Types 304 [UNS S30400] 309 [UNS S30900], 347 [UNS S34700]) were exposed to the hot flue gases in the freeboard (--lo cm below the location of the convection pass tubes). Deposits formed on the alloys contained high sulphur concentrations in their outer parts, as well as sodium, potassium, magnesium, and calcium. Sulphur appeared to be associated with calcium and magnesium, suggesting that the fly ash may have reacted further after being deposited on the surface of the coupon. Areas of high sulphur concentration also correlated well with areas of high chromium content of the inner layers of the scales. Cross sections of samples indicated that sulphur had penetrated into the alloy and reacted to form sulphide corrosion products. There was no direct evidence to show that alkali chlorides were involved in the corrosion process. No chloride was identified in the alloy samples. There was slight oxide spallation observed on all three alloys, with the degree of spallation in the following order: Type 304 > Type 347 > Type 309. 02/00559 Analysis of initial stage reactions in coal pyrolysis by molecular orbital calculation Isoda, T. ef al. Prepr. Symp. - Am. Chem. Sot.. Div. Fuel Chem., 2000, 45, (2), 234-237. Pyrolysis reactivities as well as product distributions of raw coals was evaluated using a Curie point pyrolyser. The cleaving energies of unit structures of coal were estimated by a reaction coordinate analysis based on MO calculation. The coal pyrolysis reactivity was then discussed on the basis of the cleaving energy of unit structures. 02100560 Bulgarian coals and fluidired bed technology Konstantinov, M. er al. Energetika (Sofia), 2000, 1, 30-34. (In Bulgarian) In this paper a pilot plant study of fluidized bed combustion of coal is presented. A linear regression model was developed which allows the optimization of technical, economic, and ecological parameters of the plant. 02100561 Burner for partial oxidation of carbon-containing liquid fuel Zwiefelhofer, U. et al. Eur. Pat. Appl. EP 1,016,705 (Cl. ClOJ3/50), 5 Jul 2000, DE Appl. 19,860,479, 28 Dee 1998. 6. (In German) A burner with an outlet opening directed into a combustion chamber is disclosed for partial oxidation of a liquid carbonaceous fuel with steam and an O-containing gas. The burner contains several coaxial tubes and an attached conical mixing chamber which is widened in the flow direction. A first central tube feeds the Iiquid fuel and a second tube surrounding coaxially the central tube feeds steam into the mixing chamber. A third tube surrounding the second tube and the mixing chamber feeds the O-containing gas to the outlet opening of the

(burners, combustion

systems)

burner. The mixing chamber is 10-300 mm long, has an inner diameter of 10-100 mm, and a wall inclination angle of 3-20” to the mixing chamber axis. 02lOO562 Change in the pore size distribution of brown coal along with a progress of moisture release Kumagai, H., Nakamura, K. Prepr. Symp. - Am. Chem. Sot.. Div. Fuel Chem., 2000, 45, (2), 257-260. Volume and density changes for a brown coal model molecule (Yallourn coal) with its moisture release process were simulated by using the CAMD method. Although the coal model molecule employed in this study is rather simple and small, the results appear to represent the characteristics of the brown coal, at least change in the density and micropore size distribution with moisture release. 02/00563 Clean catalytic combustion of nitrogen-bearing gasified biomass Burch, R., Southward, B.W.L. Chem. Commun. (Cambridge), 2000, 8, 703-704. Zero No, emissions are obtained in the catalytic combustion of simulated biomass derived gas mixtures containing substantial amounts of NHs by optimization of NHs oxidation and NO, reduction using a 2%Rh-AIzOs catalyst. 02100564 CO combustion model for circulating fluidized bed combustor Wang, Z. el al. Qinghua Daxue Xuebao. Ziran Kexueban, 2000,40, (2), 110-l 13. (In Chinese) For the purpose of calculating CO combustion in circulating fluidized bed combustor (CFBC), several formulas of CO oxidation rate for homogeneous gas-phase reaction were evaluated. The mechanism of CO oxidation reaction in CFBC was analysed based on the characteristics of the CFBC gas-solid structure. The concept of effective reaction space was then introduced to develop a calculational model of CO burning rate in CFBC. The calculated results are in good agreement with reported experimental results. 02/00565 Coal char thermal deactivation under pulverized fuel combustion conditions Russell, N.V. er al. Energy Fuels, 2000, 14, (4), 883-888. To examine the potential for thermal deactivation during pulverized coal combustion a high-temperature wire-mesh reactor has been used to prepare chars at heating rates of lo4 K s-t, temperatures up to lSOo”C, and hold times of O-5 s, from two Argonne Premium coals: Pittsburg No. 8, a high-volatile bituminous coal, and Pocahontas No. 3, a low-volatile high rank coal. Residual char reactivities to oxygen were determined using a non-isothermal TGA method. A comprehensive examination of the effect of preparation conditions on char reactivity is reported. Chars from the higher rank coal were relatively less reactive than chars from the lower rank coal prepared at lower temperatures, in line with accepted trends. At the higher temperatures (up to 18OO”C), more typical of full-scale pulverized coal combustion, the trend was reversed. Due to the greater propensity of the lower rank coal for thermal deactivation, high-temperature chars from the higher rank coal were found to be relatively more reactive than chars from the lower rank coal. High-temperature chars were also found to have reactivities comparable to utility fly ash carbons. Volatile yield and elemental release measurements suggested that thermal deactivation is likely to be a result of structural changes within the char matrix, rather than loss of heteroatoms from the structure. ;2/;0:5$6

Coal combustion

in Oz/COz mixtures

compared

Croiset, E. et al. Can. J. Chem. Eng., 2000, 78: (2), 402407. As part of COz abatement strategies for climate change, the coal combustion behaviour in various 02/COa mixtures and in air was studied. The goal is to simulate conditions of coal combustion with flue gas recirculation in order to maximize the COz concentration in the flue gas prior to its recovery. A western Canadian sub-bituminous coal and a US eastern bituminous coal were investigated. Thermal input was set at 0.21 MW with a flue gas oxygen concentration of 5 ~01%. Experiments were done using various O$COz mixtures and air. The oxygen concentration ranged from 21% to 42%. Up to 95% CO2 concentrations were achieved in the flue gas. This paper describes experimental results in terms of flame temperatures and pollutant emissions (NO,, SOa and CO). 02/00567 Coal powder combustion in the blast furnace Ho, S., Kim, S. Repub. Korea KR 9,510,236 (Cl. C21B5/00), 12 Sep 1995, Appl. 9,331,655, 30 Dee 1993. (In Korean) The coal powder burning method consists of steps of: (1) charging the blast furnace with a solid sample with a particle diameter ~3 mm which consists of coke alone or together with char and heating to a desired temperature; (2) finding half bandwidth for the heated sample by X-ray Fuel and Energy Abstracts

January 2002

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