Oxidized bituminous coal

Mesophase Development during Thermal Hydrogenation of an Oxidized Bituminous Coal... 

In the present work, a mild thermal hydrogenation treatment was used to revive the coking properties of an oxidized bituminous coal. The coal studied was a severely weathered high volatile bituminous coal from eastern Canada. 

An oxidized bituminous coal from Phalen Seam in Nova Scotia was obtained from the Cape Breton Development Corporation. Some properties of this coal are given in Table I. Hydrogenation was carried out in a stainless steel, vertical fixed bed reactor of 155 ml capacity Q). Approximately 150 g of sample, -4 to 8 US... 

Feedstock Evaluation. A broad spectrum of carbonaceous solids was acquired whose proximate and ultimate analyses are given in Table II. All of these feedstocks as well as oxidized bituminous coal and the coke... 

F. ferro-oxidants is capable of accelerating the oxidation of pyritic (FeSj) deposits at acid pH values. It is usually found in association with Thio-bacillus and was known as Thiobacillus ferroxidans before the distinction between the two organisms was appreciated. It is responsible for pollution problems arising from acid waters in gold and bituminous coal mines such waters are corrosive to pumping machinery and mining installations (see Fig. 2.20). 

Mahle, N.H. and L.F. Whiting. 1980. The formation of chlorodibenzo-p-dioxins by air oxidation and chlorination of bituminous coal. Chemosphere 9 693-699. 

Sulfur in the biomass feedstock can be converted to hydrogen sulfide or sulfur oxides during gasification. Wood typically contains less than 0.1% sulfur by weight, and herbaceous crops may contain 0.3 to 0.4%. Some feedstocks such as refuse-derived fuel (RDF) may contain 1% or more, approximately the same as bituminous coal. As a result of the low levels of sulfur in the biomass, the concentrations of H2S and SOx levels in the product gases are below those requiring cleanup in most applications. 

Over the initial period of conversion, it was also observed that only small quantities of light hydrocarbon gases were produced. The liberation of carbon oxides, principally CO2, was more facile. For both subbituminous and bituminous coals, the yields of CO2 realised at 300 C were significant, although much higher for the lower rank coal (8.9). 

Py-FIMS results clearly reveal the existence of a thermally extractable, bitumen-like fraction which is chemically distinct from the remaining coal components. In lignite, several biomarker compounds were noticeable in the mobile phase components while bituminous coals contain various alkylsubstituted aromatic compounds in the mobile phase. Blind Canyon coal, which contains 11% resinite, exhibits mobile phase components believed to originate from terpenoid aromatization. Curie-point Py-LVMS results illustrate the importance of the oxidation status of coal for studying the mobile phase since mild air oxidation severely changes the structural characteristics of the thermally extractable mobile phase. 

Coke is obtained by destructive distillation or carbonization of bituminous coal, coal-tar pitch and petroleum produced during petroleum cracking. Coke from bituminous coal is used to reduce iron ore in blast furnaces and to produce synthesis gas. Petroleum coke or that obtained from coal-tar pitch is used in electrolytic reduction of aluminum oxide to aluminum and in the preparation of several metal carbides.. ... 

S.W. Martin, USP 2812246 (1957) CA 52, 3346 (1958) claims prepn of impact-resistant LOX from an adsorbent carbon obtained by flash-oxidation-calcination of a finely divided swelling bituminous coal (with a volatile content of >12%) in a stream of oxygen-contg gas at 800° or more. An expl prepd from this carbon was insensitive to impacts of >1200ft-lb. It failed to detonate when burned in semi-confinement with a 0.25 inch... 

Much of the quartz in the fly ash originates from the coal as silt- and sand-sized particles, and it remains in the ash because it survives thermal transformation during the combustion process (Helmuth 1987). Small amounts of volatilized Si may also oxidize to form very fine crystals of quartz within the fly ash glass (Diamond 1984 Hubbard et al. 1984). Although bituminous coal ash may contain more than 50 wt% analytical Si02, only 5-10 wt% of it is present in the form of quartz (McCarthy et al. 1990). Some Si is present in the mineral mullite, but the majority of it is in the amorphous glass phase. 

Production. Silicon is typically produced in a three-electrode, a-c submerged electric arc furnace by the carbothermic reduction of silicon dioxide (quartz) with carbonaceous reducing agents. The reductants consist of a mixture of coal (qv), charcoal, petroleum coke, and wood chips. Petroleum coke, if used, accounts for less than 10% of the total carbon requirements. Low ash bituminous coal, having a fixed carbon content of 55—70% and ash content of <4%, provides a majority of the required carbon. Typical carbon contribution is 65%. Charcoal, as a reductant, is highly reactive and varies in fixed carbon from 70—92%. Wood chips are added to the reductant mix to increase the raw material mix porosity, which improves the SiO (g) to solid carbon reaction. Silica is added to the furnace in the form of quartz, quartzite, or gravel. The key quartz requirements are friability and thermal stability. Depending on the desired silicon quality, the total oxide impurities in quartz may vary from 0.5—1%. 

George Kapo. What do you think is the relation between humic acids produced by the oxidation of bituminous coals and the humic adds you worked with ... 

Dr. Steelink. We have not worked with humic acids from bituminous coals. In general, the carbonyl and phenolic content of an oxidized coal would be the most important structural properties in contributing to EPR phenomena such as we have described. 

If vesiculation or decrepitation took place in the carbon at this stage, the increased surface area would enhance subsequent oxidation. Such vesiculation is described by Clegg (9) for carbonized bituminous coals. 

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