Fuel and related compositions – Liquid fuels – Aluminum or heavy metal – other than lead – containing
Patent
1982-12-27
1984-11-13
Dees, Carl F.
Fuel and related compositions
Liquid fuels
Aluminum or heavy metal, other than lead, containing
44 15R, 209127A, C10L 500, C10L 900
Patent
active
044823517
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for removing ash from coal, and more particularly to a process for purifying pulverized coal by effectively eliminating coexistent ash therefrom.
BACKGROUND ART
While pulverized coal is chiefly composed of carbon particles, it also contains as impurites particulate ash such as particles of SiO.sub.2, CaO, Al.sub.2 O.sub.3, etc. When put into use as fuel, pulverized coal should advantageously contain no or at least reduced ash. A conventional method heretofore employed to purify pulverized coal comprises adding pulverized coal to water followed by stirring, and subsequently adding to the mixture oil as a separating agent again followed by agitating. Ash can be separated and removed from the coal by utilizing the lipophilic property of coal. With such a method, however, not only is the working efficiency low but also is it difficult to control separation accuracy.
DISCLOSURE OF THE INVENTION
It is an object of the present invention to provide a process for removing ash from coal which is excellent in working efficiency and which provides easy control of separation accuracy.
To fulfil this object, the present invention provides a process for removing ash from coal comprising the steps of transferring pulverized coal to be treated by entraining it on a stream of non-oxidizing gas, feeding the coal laden gas into dry-type electric precipitating chamber means after suitably adjusting the temperature and humidity of the gas during transport, and separating particulate ash from the coal particles by capturing the former in the precipitating chamber means by virtue of difference in specific resistance between the two kinds of particles, whereby highly purified coal is obtained as entrained on the gas stream at the outlet of the chamber means.
The non-oxidizing gas usable in this method comprises one or any combination of carbon dioxide gas, nitrogen gas and an inert gas.
Needless to say, the temperature and humidity of the coal laden non-oxidizing gas stream should preferably be so adjusted that the degree of separation of the particulate ash from the carbon particles is increased to the greatest extent. For example, the humidity is set to 10%, and the temperature to 100.degree.-200.degree. C.
The features and effects of the present invention will become apparent from the following description of an embodiment given with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawing is a schematic view showing a coal treating system for effectively carrying out the invention.
BEST MODE OF CARRYING OUT THE INVENTION
In the drawing illustrating a coal (pulverized coal) treating system, numeral 1 represents a hopper for storing pulverized coal to be treated; numeral 2 a drytype electric precipitator disposed downstream from the hopper 1; numeral 3 a discharge duct extending from the precipitator 2; numeral 4 a blower provided in the duct 3; numeral 5 a feed duct connecting the entrance of the precipitator 2 and the outlet of the hopper 1; numeral 6 a discharge means provided in the outlet of the hopper 1 for discharging constant amounts of pulverized coal; and numerals 7 and 8 a temperature adjusting unit and a humidity adjusting unit, respectively, disposed in or on the feed duct 5.
A non-oxidizing carrier gas comprising carbon dioxide gas, nitrogen gas, an inert gas or the like is supplied through one end of the feed duct 5 close to the hopper 1. The arrow A in the drawing indicates the flow of the carrier. Pulverized coal continually discharged, in constant amounts, from the hopper 1 by the discharge means 6 is entrained on the carrier gas and transferred toward the precipitating chambers of the electric precipitator 2 by the drawing action of the blower 4. Before entering the precipitator 2, the coal laden gas is heated to a predetermined temperature by the temperature adjusting unit 7 and humidified by the humidity adjusting unit 8 to a humidity of not less than 10% for example. The gas then enters the precipitating cham
REFERENCES:
patent: Re21302 (1939-12-01), Grote
patent: 1153182 (1915-09-01), Schniewind
patent: 3809373 (1974-05-01), Brock
patent: 3909211 (1975-09-01), Diaz et al.
patent: 4053285 (1977-10-01), Robinson
Kitazawa Kohji
Ozaki Toshio
Dees Carl F.
Farley Joseph W.
Hitachi Shipbuilding & Engineering Co. Ltd.
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