Ignition of lignite in a fluidized bed

Ignition of lignite in a fluidized bed

09 Combustion (burners, combustion systems) 96/02955 Heat release mechanisms In inhibited laminar counterflow flames Yong Lee, K. et al., Combustion...

161KB Sizes 0 Downloads 54 Views

09

Combustion (burners, combustion systems)

96/02955 Heat release mechanisms In inhibited laminar counterflow flames Yong Lee, K. et al., Combustion & Flame, Jan. 1996, 104, (1), 27-40.

96/02963 The influence of heterogeneous kinetics and thermal radiation on the oxidation of graphite particles Chelliah, H. K. Combustion & Flame, Jan. 1996, 104, (I), 81-94.

Due to the participation of inhibitors in flame chemistry, it is difficult to concurrently characterize the complex interaction between their cooling action and chemical inhibition (which decrease temperature), and their contribution of heat release (which increases temperature). The study investigated the effect of chloromethane (a chemical inhibitor due to its halogenation) on the heat release in methane-air nonpremixed flames. For comparison, the effect on the heat release due to the purely thermal action of nitrogen (which does not exhibit chemical inhbition or heat release effects) was also investigated.

Numerical integrations have been performed to study the influence of porosity and radiation on the combustion of spherical graphite particles in a quiescent atmosphere. Two sets of heterogeneous rate constants, one assuming no internal burning and another assuming partial internal burning have been employed for this purpose. Based on the quasi-steady burning conditions, the numerical predictions have shown for nonporous particles the existence of a critical particle diameter below which strong burning conditions cannot be sustained. This critical particle diameter is found to be a strong function of the porosity. The influence of thermal radiation on the burning characteristics has also been examined and a complex interaction identified between surface kinetics, gas-phase kinetics, mass transport through the boundary layer and thermal radiation.

96/02956

Ignition of coal-dust particles in shock waves

Kiselev, S. P. and Kiselev, V. P. PMTF, Prikl. Mekh. Tekh. Fiz., 1995,36, (3), 31-37. (In Russian) Presents the results of modelling of behaviour of coal-dust particles in shock waves. It was shown that heating of the gas in the particles cloud leads to their ignition in passing shock waves.

96/02957

Ignition of lignite In a fluidized bed

Liu, H. et al., Huazhong Ligong Daxue Xuebao, 1995, 23, (4), 120-123. (In Chinese) Describes the investigation into the effects of the heating rate, particle size, and fluidizing velocity on the ignition temperature of lignites with a thermogravimetric analyzer and a fluidized bed combustor.

96/02958 Ignition of non premixed counterflowlng hydrogen versus heated air: Computational study with detailed chemistry Kreutz, T. G. and Law, C. K. Combustion & Flame, Jan. 1996, 104, (1), 157-175. Forced ignition in counterflowing jets of N2-diluted H 2 versus heated air has been investigated over a wide range of temperature, pressure, and strain rate by numerical modelling with detailed chemistry and transport.

96/02964 flames

Clausen, S. Proc. SPfE-Int. Soc. Opt. Eng., 1995, 2506, 30-44. The paper describes the effects of flame fluctuations, occurring naturally during the measurement of FT-IR spectra. The results from applications on an oil flame, a pulverized coal flame and a full-scale waste incinerator are also described.

96/02965 Intrinsic kinetics and mechanism of sulfur release from Maoming oil shale during combustion Wang, G. et al., Shiyou Daxue Xuebao, Ziran Kexueban, 1995, 19, (2), 92-96. (In Chinese) The high purity of organic matter and mineral matter were separated from Maoming oil shale by acid treatment to remove mineral matter and by low temperature ashing to remove organic matter, respectively. Intrinsic kinetics of S02 evolution during organic matter and mineral matter combustion was studied at the rate of 5°/min in a programmed temperature apparatus using an in situ S02 analyzer. The results indicated that temperatures of marked SO/ evolution from organic S are 210-470°; kinetic parameters were also obtained.

96/02966 96/02959 The Influence of carbon dioxide on smoke formation and stability in methane-oxygen-carbon dioxide flames Hainsworth, D. et al., Fuel, Feb. 1996, 75, (3), 393-396. The effect of replacing nitrogen in combustion air by carbon dioxide in a laminar, atmospheric methane diffusion flame was investigated experimentally and by numerical modelling. Measurements included flame temperature, carbon monoxide concentrations and direct observation and photographic investigation of the flame shape and behaviour. The experimental results indicate a substantial reduction of scattered light intensity and flame volume. When a sufficient amount of carbon dioxide is added to the oxidant, the sooting tendency and flame volume are reduced. In addition, the effect of replacing nitrogen by carbon dioxide in the flame gases on the rate of formation of key combustion intermediates, such as hydroxyl radicals and ethyne, flames gases on the rate of formation of key combustion intermediates, such as hydroxyl radicals and ethyne, was investigated theoretically.

96/02960 Influence of catalysts on pulverized coal combustion characteristics Xu, W. and Du, H. Ranliao Huaxue Xuebao, 1995, 23, (3), 272-277. (In Chinese) Discusses the influence of various catalysts on the combustion characteristics of bituminous and anthracite coals.

96/02961 Influence of cerium oxide on the formation and oxidation of soot Lahaye, J. et al., Combustion & Flame, Jan. 1996, 104, (1), 199-207. Soot was produced by pyrolysis and oxidative pyrolysis of hydrocarbon doped with cerium organometallic compounds. More than 90% of the cerium is found in and on the soot particles. Soot containing up to 10% Ce by weight was prepared. The presence of cerium-based compounds has no effect on the yield or the morphology of soot. The soot samples were oxidized by oxygen diluted in an inert gas at 5% to 20% by volume either under linear heating rate conditions (2 Klmin) or isothermally up to 750°C. The cerium (as cerium oxide) strongly decreases the ignition temperature of the soot. The influence of the Ce content of soot on the kinetics of oxidation is described and the experimental temperatures of soot ignition are compared with the values derived from the Semenov theory.

96/02962 Influence of coal properties on N,20 generation during combustion in a circulating fluidized bea Liu, H. et al., Huazhong Ligong Daxue Xuebao, 1995,23, (5), 100-103. (In Chinese) Ten kinds of coal widely used in power plants have been tested during circulating fluidized bed combustion to study the influence of coal properties, such as volatile matter content, nitrogen content etc. on N,O and NO, formation.

206 Fuel and Energy Abstracts May 1996

Infrared combustion diagnostics in fluctuating

Jaworzno III cleans up

MPS, Modern Power Systems, Nov. 1995, 15, (11), 43, 45, 47. Reports that two boilers at the Jaworzno III 1200 MW coal fired power plant in Poland will be retrofitted with Babcock-Hitachi NR-2 low NO, burners. The burners will be supplied by Tampella in Finland under an IVO contract which marks an important opening in the Polish energy market.

96/02967 Kinetic characteristics of reducing NO. In combustion products with injection of secondary fuel Su, S. et al., Huanjing Kexue Xuebao, 1995, 15, (3), 330-335 (In Chinese) A reduced zone of NO, in the chamber of the coal-fired boiler of a power station was created with injection of second fuel to control NO, emissions. The mathematical model and the chemical kinetic model were established, which describe dynamic process of NO, reduction. Compares the results with those measured values.

96/02968 Mathematical model of NO. formation in a fluidizedbed combustor Orlyk, W. M. et al., Ekotekhnol. Resursosberezhenie, 1995, (3), 48-52. (In Russian) A mathematical model previously developed by the authors was expanded to take into account the formation and reduction of NO, in coal combustion. The formation of thermal NO, was assumed to proceed by the Zeldovich mechanism; fuel-derived NO, was assumed to result from homogeneous reactions with participation of fuel-derived ammonia. The calculated total values of NO, were in satisfactory agreement with experimental ones.

96/02969 Mathematical model of strongly swirling gas-parti. cle turbulent flow and pulverized coal combustion and its application to a vortex combustor. (I) Model Zhang, 1. and Nieh, S. Huagong Xuebao, 1995, 46, (5), 545-551. (In Chinese) Describes a two-dimensional model of strongl y swirling gas-particle turbulent flow and pulverized coal combustion. The goal is the numerical simulation of multiphase flow, heat transfer, and combustion in vortex combustor.

96/02970 Mathematical model of strongly swirling gas-particle turbulent flow and pulverized coal combustion and its application to a vortex combustor. (II) Application Zhang, J. and Nieh, S. Huagong Xuebao, 1995, 46, (5), 552-556. (In Chinese) Describes a two-dimensional mathematical model of strongly swirling gasparticle turbulent flow and pulverized coal combustion developed and formulated in paper (I) was applied to the systematic numerical simulation of isothermal gas flow, gaseous combustion, and pulverized coal combustion in a coal-fired vortex combustor. General agreement was achieved between the calculated results and the cold flow and combustion test data.