Daw Mill Research Articles

97/04598 Gasification and char combustion reactivities of Daw Mill coal in wire-mesh and ‘hot-rod’ reactors: Lim, J.-Y. et al. Fuel, 1997, 76, (13), 1327–1335

97/04598 Gasification and char combustion reactivities of Daw Mill coal in wire-mesh and ‘hot-rod’ reactors: Lim, J.-Y. et al. Fuel, 1997, 76, (13), 1327–1335

Gasification and char combustion reactivities of Daw Mill coal in wire-mesh and ‘hot-rod’ reactors

The pyrolysis and CO 2-gasification behaviour of Daw Mill (UK) coal was investigated using wire-mesh (WMR) and fixed-bed ‘hot-rod’ (HRR) reactors. Experiments were performed at pressures between 0.1 and 3 MPa at 850 and 1000°C. These reaction conditions reflect those of novel power plant technologies (e.g. ABGC) in which coal gasification and char combustion reactivities are relevant to design and operation. Untreated coal samples were used in all experiments rather than pre-prepared chars as appears more usual. CO 2 gasification reaction rates were directly calculated from the difference between mass loss in pyrolysis and during gasification in CO 2. Combustion reactivities of the chars from these experiments were determined in an atmospheric pressure thermogravimetric balance. The partitioning of the original sulfur and nitrogen contents between the volatiles released in the gasifier and the char transferred for combustion in the CFBC were determined. Differences in mass loss between gasification and inert pyrolysis were found to be significantly greater in the wire-mesh reactor, where more efficient gas-solid contact takes place and tar condensation on reacting char is minimized. Whilst combustion reactivities of the CO 2-gasification chars were lower than their pyrolysis counterparts and tended to decline slightly with increasing pressure, reactivities of chars prepared in the HRR were systematically lower than those from the WMR. The reactivities of four other coals were also tested at 1000°C and 2 MPa. A straightforward decline in pyrolysis mass loss was found with increasing rank. However, even within the limits of the small number of samples tested, considerable scatter was found in the reactivities of middle-rank coals, probably due to a combination of structural factors, including differences in char pore structure, catalytic effects of mineral matter components and differences in the inherent reactivity of the carbonaccous matter. The percentages of coal nitrogen and sulfur retained in the residual chars generally declined with increasing pressure; reactive gases appear to remove char nitrogen more efficiently, suggesting that pyrolysis experiments may not be a good guide to char nitrogen partitioning in gasification and combustion.

The design and selection of powered supports for application in 4.5 metre extraction at Daw Mill Colliery : C. Chadbourne, in: Proc. 13th international conference, ground control in mining, Morgantown, WV, 1994, ed. S.S. Peng, (WVU/USBM), 1994, pp 148–156

The design and selection of powered supports for application in 4.5 metre extraction at Daw Mill Colliery : C. Chadbourne, in: Proc. 13th international conference, ground control in mining, Morgantown, WV, 1994, ed. S.S. Peng, (WVU/USBM), 1994, pp 148–156

Fluorescence of extracts of Daw Mill coal

Fluorescence of extracts of Daw Mill coal

Major reconstruction at Daw Mill Colliery : Boyle, J C Min EngrV143, N272, May 1984, P541–549

Major reconstruction at Daw Mill Colliery : Boyle, J C Min EngrV143, N272, May 1984, P541–549

Metalloporphyrins in coal. 1. Gallium porphyrins in bituminous coals

The isolation and characterisation of a homologous series of gallium polyalkylporphyrins from a large scale extraction of a bituminous coal (Daw Mill) from the Carboniferous is described. About 0.2 µg/g of metalloporphyrin fraction is obtained. The homologous series extends from C26 to C32. It is proposed that the homologues arise by fragmentation (thermal cracking, protodesubstitution on a mineral surface) of etioporphyrin III or its metal complexes during the coalification process.

Design and operation of three metre extraction faces with heavy duty equipement at daw mill colliery : Drake, D; Wright, D M Min Engr, V141, N239, Aug 1981, P97–104

Design and operation of three metre extraction faces with heavy duty equipement at daw mill colliery : Drake, D; Wright, D M Min Engr, V141, N239, Aug 1981, P97–104

Metals and metal complexes in coal

Some of the metal compounds that occur in coal are soluble in organic solvents and are extracted in coal liquefaction processes. The material made by the extraction of coal with hydrogenated anthracene oil has been fractionated by sequential Soxhlet extraction with low-boiling solvents, and the distribution of the metallic elements in the various fractions has been determined. Extraction of Daw Mill coal (92 kg) with acidic methanol furnishes 17.8 mg of a mixture of gallium complexes of homologous porphyrins (C 27 -C 32 ). Similar metalloporphyrin concentrates are obtained from a variety of British bituminous coals, the amount detected being about 1 pg/g, but falling off as coal rank increases. Various lignites and a range of Polish coals have also been surveyed: here, iron porphyrins and (in one case) manganese porphyrins have been observed. The iron porphyrins tend to be confined to coals of lower rank : in the lignites, metal-free tetrapyrroles are also detected. The metalloporphyrins are thought to be derived from the chlorophylls and haems of the biological precursors. Indeed, it is possible that the iron porphyrins are derived directly (i.e. without demetallation-metallation) from biological and microbiological haem compounds.

Proceedings

Joint meeting between Engineering Groups and the British Tunnelling Society 8 April 1975 Some problems of shaft sinking, with particular reference to South Africa P. F. F. Lancaster-Jones Shaft sinking at Boulby Mine, Cleveland Potash Ltd. M. Grieves Film: Daw Mill Shaft Sinking 11 April 1975 Venus and Mercury Report on the joint meeting of the Royal Astronomical Society, Royal Meteorological Society and the Geological Society. Held at the Scientific Societies Lecture Theatre, Saville Row, London WCi. By G. E. Hunt & J. E. Guest The recent successful Mariner 10 space mission to Venus and Mercury has provided a wealth of new information which has dramatically altered our understanding of these innermost planets. The first session was concerned with Venus, and Dr G. E. Hunt discussed our present knowl- edge of the structure of the atmosphere and clouds. He showed Mariner to pictures of the Venus limb which indicated aerosol layers only 1 km thick in the stratosphere between the 10–50 mb pressure levels. The cloud structure beneath the 50 mb is not known with precision, although a sulphuric acid cloud seems to occur in the 50–100 mb range, the lower atmosphere is opaque to radiation at wavelengths shorter than the microwave, and any information beneath the ubiquitous clouds can only be determined by space probes. Dr Hunt suggested that there is some evidence of two layers of cloud beneath the 50 mb level, but stressed that it was controversial. Although most of the solar energy is absorbed