02921 Co-combustion of miscanthus in a pulverised coal combustor: Experiments in a droptube furnace

02921 Co-combustion of miscanthus in a pulverised coal combustor: Experiments in a droptube furnace

07 Alternative energy sources (bioconversion Biomass-derived 97102917 fuels Wvman. C. E. 1965, oxygenates energy) for the droptube experiments. T...

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07

Alternative energy sources (bioconversion Biomass-derived

97102917 fuels Wvman. C. E. 1965,

oxygenates

energy) for

the droptube experiments. The validation was successful. The model was

transportation

Proc. ~iomcro Cortf. Am .: Errera. Environ.,

Agric.

Ind..

Zud,

devolatilization

behaviour

in a

966-975.

The transportation sector in the US is the only element that is almost totally dependent on petroleum for its energy supply. With more than half of all petroleum imported, transportation, which is vital to the US economy, is very vulnerable to economic and strategic disruptions. With about twothirds of all oil being used for transportation. it also contributes substantially to the large trade deficit for petroleum imports. Transportation fuels contribute about half the urban air pollution and a third of the carbon dioxide accumulation that could result in global climate change. Because lignocellulosic biomass sources such as agricultural and forestry residues, municipal solid waste, and woody and herbaceous crops could be abundant, production of fuels from biomass could address all these problems on a large scale. Biomass can be gasified by thermal processes to produce a mixture of carbon monoxide and hydrogen that can be catalytically combined to form methanol. Alternatively, the cellulose and hemicellulose in biomass can be broken down to their component sugars for fermentation to ethanol. Although ethanol and methanol are currently most favored for use as transportation fuels, other acohols could also be formed thermally or biologically from biomass. Ethanol and methanol can be used directly as neat or pure fuels. Ethanol is also directly blended with gasoline to displace gasoline use, increase the octane of the blended fuel, and provide oxygen that insures more complete combustion and reduces the contribution to urban air pollution.

Calculation

97102918 fuels

of higher

heating

values

of biomass

Demirbas, A. Fuel, 1997, 76, (S), 431-434. Calorific values (higher heating values, HHV) of 16 biomass samples obtained from different Turkish sources were determined experimentally and calculated from both ultimate and proximate analyses.

Carbohydrate biofuels. 97102919 Mexico, Brazil, Zimbabwe and India Shultz, Environ.,

E. B., Jr. and Bragg, W. G. Agric.

Ind.,

2nd.

1995.

I.

Rootfuel

studies

in

Proc. Biomass Conf. Am.: Energy,

313-322.

By the process of drying the fast-growing starchy-cellulosic taproots of certain members of the family Cucurbitacean, ‘root fuel’ is produced. It has been under investigation by us since 1985. Rootfuel can be dried quickly to a much lower moisture content than seasoned wood, and also, unlike wood, it contains a very small amount of lignin. If it is dry and burned with good draft, it can be burned more slowly than wood with very little smoke production. Root fuel made from Cucurhita foetidissima roots in dry, deforested and well-populated rural lands of Mexico, Brazil, Zimbabwe and India were studied, under sponsorship of the Biomass Users Network, with funding from the Rockefeller Foundation. The study aimed to evaluate root fuel as a replacement for wood, dung and crop residues to improve indoor air quality for health reasons, and to take pressure off of the remaining trees. Small test plots have been planted. and new root fuel species have been identified and tested.

97102920 Characteristics and availability of biomass and residues in the Netherlands for gasification

waste

Faaij, A. et al. Biomass und Bioenergy, 1997, 12, (4), 225-240. The paper evaluates the characteristics and availability of biomass waste streams and residues for power production by means of integrated gasification/combined cycle technology (BIG/CC) for The Netherlands. Four main categories are investigated: streams from agriculture; organic waste; wood; and sludges. Altogether 18 different streams are distinguished. Gross availability and net availability are inventorized. Various properties are analysed and the suitability of these streams for conversion in a BIG/CC unit is studied. The costs at which various streams are likely to be available are assessed. Some streams require mixing with cleaner fuels to make them suitable for use in a direct atmospheric biomass integrated gasifier/combined cycle system. Important technical limits for the use of biomass fuels in the system studied, are the moisture content and ash content of the fuel.

97102921 combustor:

Co-combustion of miscanthus in a pulverised experiments in a droptube furnace

coal

Wagenaar, B. M. and Van Den Heuvel, E. J. M. T. Biomass and Bioenergy, 1997, 12, (3), 185-197. The devolatilisation process of Miscanthus particles inside a pulverized coal combustion chamber is characterized in this work, with the aim of finding conditions for which the devolatilization rate of coal and Miscanthus is similar. Due to the scale of operation ( > 500 MW), BTG has designed and constructed a droptube reactor for well-controlled Miscanrhus devolatilization experiments with operational conditions that resemble those of a pulverized coal combustor. The experimental study on high-temperature Miscanthus decomposition in the droptube showed that Miscanrhus particles which belong to the smallest sieve fraction (0.6-l mm) could he devolatilized completely in a 1.6 m long droptube. Apart from the experimental investigation, a numerical model has been developed. Samples of Miscanrhus particles, representing grass-/straw-like crops, have been characterized in detail with respect to their size distribution. These data have been used to validate the numerical model with the results from

240

then applied to predict the Miscanrhus pulverized coal power station.

Fuel and Energy Abstracts

July 1997

Co-processing

97102922

of agricultural

and biomass

waste

with coal 1996, 49, (l-3). 167-175 Stiller. A. H. et al. Fuel Process. Techno/., Blind Canyon seam coal was liquefied in the presence of one of four different types of co-liquefaction agents (CLAs) at 350’ and 1000 psi H,. The role of Tetralin solvent was studied. The four CLAs used were sawdust, horse manure, cow manure, and commercial ‘Super Manure’. Conversion and the asphaltene-plus-preasphaltene yield were obtained by successive dissolution in THF and hexane, respectively, with the oil-plus-gas yield obtained by difference. A study of the incremental differences in conversions and yields indicated that the four CLAs interact with coal and Tetralin in different ways. Incremental conversion and the asphalteneplus-preasphaltene yield appeared to be related to the amount of hemicellulose in the CLAs (e.g. manure), whereas the incremental oilplus-gas yield appears to he related to the amount of lignin (sawdust). Incremental improvements seemed to be negated with the addition of inorganic compounds in the oil-plus-gas yield when Tetralin is present. 97102923

different

Comparative waste materials

study

of

biogas

production

from

Mandal, T. and Mandal. N. K. Energy Com~erv. &VII, 1997. 3X. (7), 67% 683. The biogas generation capacity of each mixture and its individual components of varitms categories of waste materials were determined through experimental studies. The best waste material, that can produce the maximum amount of biogas from each category of waste materials, has heen found at a specific temperature of 37°C. 97102924 Concentrations of inorganic elements fuels and recovery in the different ash fractions

in biomass

Obfrnberger, I. ef al. Biormss and Bioenergy, 1997, 12, (3). ?I I-221. The combustion process and the composition of the ashes produced arc influenced by the inorganic elements and compounds in biomass fuels. Consequently, knowledge about the material fluxes of inorganic clemcnts and compounds during biomass combustion for different kinds of biofuels and their influencing variables is of great importance for the future design and control of biomass furnaces and boilers. For this reason. comprehensive test runs were carried out in several biomass combustion plants equipped with different combustion technologies and using various biomass fuels (wood chips, bark, straw and cereals). During continuous observation periods of at least two days, samples of the biomass and the different ash fractions were taken and analysed. Furthermore. the most important operating data of the plants were recorded. The results indicate that a major requirement for a sustainable ash utilization is a fractionated heavy metal separation, distinguishing between different fly-ash fractions and taking the temperature of fly-ash precipitation into consideration tar new furnace technologies. Research has also shown that straw and ccrcals. as well as their ashes, contain significantly lower amounts of heavy metals than woody hiofuels and wood ashes. 97102925 Effects on SO, straw and pulverized coal

and

NO,

emissions

by co-firing

Pederson, L. S. Enera> Fuelr, 1997. I I, (2), 439-446. An investigation was carried out to study the effect of co-firing straw and pulverized coal in a 2.5 MWt pilot-scale burner and a 2.50 MWe utility boiler. In the 2.5 MWt trial the straw was chopped and fed separately to the burner, whereas in the full-scale experiment the straw was pre-processed as pellets and ground with the coal in the mills. Two low-sulfur coals and one high-sulfur coal were used in the pilot scale, whereas a high-sulfur coal was used at full-scale. Results from both tests revealed that an increased fraction of straw in the fuel blend resulted in a reduction of NO and SOL emissions.

97102928

Industrial

use of biomass

energy

in Sri Lanka

Tariq. A. S. and Purvis, M. R. I. In! J. Energy Res.. 1997, 21. (5). 447-464. The use and sustainability of biomass as an industrial fuel is investigated tn this article. Data from a field study is presented on biomass supply and availability, costs of energy in key industries and the annual environmental burdens due to the emissions of carbon dioxide and nitrogen oxides to the

atmosphere. Emissions reductions estimates are made, as well as improvements in the sustainability of fuel woods from point of view of the thermal efficiency of combustion plant. 97102927 The inorganic chemistry aspen wood with added sulfur Blander, M.

Biomas

and

Bioenergy,

of the

combustion

of

1997, 12, (4), 289-293.

The paper describes the experiment. The inorganic chemistry of the combustion of 100 gm of aspen wood was calculated at 4 and IO atm with 0.115 gm of added sulfur. The sulfur reacted with potassium and calcium to form a liquid sulfate phase which crystallized at 908’C at 4 atm and 912 C at IO atm and eliminated a fouling and potentially corrosive molten carbonate phase which would have been present between Xl)0 and 900°C with no added sulfur. Deposition of the refractory solids from the combustion gases at about 1000°C before adding sulfur would raise the temperature, below which no liquid will form to almost IOOO’C. The mole