Briquetting process

Patent metadata

Field	Value
Publication number	US-RE46052-E
Application number	US-201314099634-A
Country	US
Kind code	E1
Filing date	Dec 6, 2013
Priority date	Feb 11, 2003
Publication date	Jul 5, 2016
Grant date	Jul 5, 2016

Abstract

A process and system for briquetting particulate matter such as moisture-containing bituminous and sub-bituminous coal includes partially drying and feeding the particulate matter to a briquetting apparatus under conditions such that water vapor is released from the particulate matter during feeding. The released water vapor substantially displaces or prevents the ingress of a large proportion of other gaseous components from the atmosphere surrounding an/or intermixed with the particulate matter. The particulate matter is surrounded by and intermixed with a gaseous component containing 70% to 100% by volume of water vapor where it enters the briquetting apparatus, such that when the particulate matter is compressed, the water vapor liquefies and the pressure buildup in the thus-formed briquettes is minimized. This reduction in the pressure buildup reduces blow-back of gases as the coal fines are formed into briquettes.

First claim

The invention claimed is:

1. A process for briquetting particulate bituminous matter containing moisture, comprising:
partially drying the particulate bituminous matter under process conditions including a temperature of above 100° C. and for a period which will raise the temperature of the particulate bituminous matter to above 90° C. and decrease the total moisture content of the particulate bituminous matter to between 1% and 10% by weight of the particulate bituminous matter;
maintaining the temperature of the partially dried particulate bituminous matter above 80° C. whilst feeding the particulate bituminous matter towards a briquette forming part of a briquetting apparatus along a feed path from which the ingress of ambient air is excluded, thereby causing water vapor driven from the particulate bituminous matter to substantially displace ambient air and other gasses from the interstices between the particles of the particulate bituminous matter as the particulate bituminous matter moves towards the briquette forming part of the briquetting apparatus;
feeding the partially dried particulate bituminous matter into the briquette forming part of the briquetting apparatus, wherein feeding the partially dried particulate bituminous matter into the briquette forming part of the briquetting apparatus comprises using at least one precompaction auger, and applying a back pressure to said particulate bituminous matter using said precompaction auger and precompacted particulate bituminous matter to define a tortuous path to assist in further reducing blow-back of gases through the particulate bituminous matter being fed to the briquetting forming part of the briquetting apparatus; and
briquetting the particulate bituminous matter in the briquette forming part of the briquetting apparatus at a pressure which is sufficient to cause the entrained water vapor to condense, wherein
the briquette forming part of the briquetting apparatus includes a pair of rollers through which the particulate bituminous matter passes, at least one of the rollers having pockets formed therein for assisting in defining the shape of the briquettes, and the process further comprises
rotating the pair of rollers at peripheral roll speeds from 113.1 m/min to 188.5 m/min and applying a loading with the rollers within a range of 115 kN/cm to 150 kN/cm.

2. A process according to claim 1 in which water vapor prior to undergoing condensation comprises 70% to 100% of the gas in the interstices between particles.

3. A process according to claim 1 in which the particulate bituminous matter is chosen from a group consisting of organic materials including wood dust, peat, lignite, brown coal, anthracite and bituminous and sub-bituminous coals.

4. A process according to claim 1 wherein the formed briquettes undergo evaporative cooling for preventing spontaneous combustion.

5. A process according to claim 4 wherein evaporative cooling is achieved by a spray arrangement for lowering the temperature of the briquettes to below 50° C. and maintaining the moisture level close to the equilibrium moisture level of the briquettes.

6. A process according to claim 1 wherein partially drying the particulate bituminous matter takes place in a flash dryer, in which the particulate bituminous matter is injected into a hot gas stream flowing through a conduit, the particulate bituminous matter being entrained by the hot gas stream which causes the temperature of the particulate bituminous matter to be increased, and the gas stream with the entrained particulate bituminous matter then passing through one or more cyclones in which the particulate bituminous matter is separated from the gas stream.

7. A process according to claim 6 wherein the separated gas stream leaving the cyclone or cyclones is partially recycled to the flash dryer with the excess gas being vented, the vented portion of the gas stream passing through a fines removing device for removing fines that pass with the gas stream through the cyclones.

8. A process according to claim 7 wherein the portion of the gas stream that is recycled to the flash dryer is reheated prior to injection of the particulate bituminous matter into the flash dryer, with the amount of gas that is vented corresponding to the volume of combustion product gas and the volume of non-condensed water vapor driven off from the particulate bituminous matter.

9. A process according to claim 1 including rotating the rollers at differing speeds for applying a predetermined amount of shear to the particulate bituminous matter as it passes between the rollers and is formed into briquettes.

10. A process according to claim 1 wherein the a ratio of the briquette pocket width to roller diameter falls within the range of 0.05 to 0.15.

11. A process according to claim 1 wherein the particulate bituminous matter is fed to the briquette forming part of the briquetting apparatus at a temperature ranging from 100° C. to 120° C.

12. A process according to claim 1 wherein the condensable gas generates a pressure ranging from 100 kPa to 200 kPa (absolute) within the briquette forming part of the briquetting apparatus.

13. A process according to claim 1 wherein the temperature of the particulate bituminous matter is maintained above 100° C. whilst feeding the particulate bituminous matter towards the briquetting forming part of the briquetting apparatus.

14. A process according to claim 1 wherein the particulate bituminous matter is partially dried such that the total moisture content is between 5% and 8% by weight of the particulate bituminous matter.

15. A process according to claim 1 wherein the briquetting forming part of the briquetting apparatus serves to distort the shape of the particulate bituminous matter to substantially eliminate voids between particles and cause the condensed water vapor to be re-adsorbed into the particulate bituminous matter and individual particles to be chemically bonded together.

16. A process for briquetting particulate matter, comprising:
partially drying the particulate matter;
feeding the particulate matter to a briquetting apparatus under gas-forming conditions of temperature and pressure in which a condensable gas is released from the particulate matter during feeding, wherein the condensable gas is allowed to displace and/or prevent the ingress of other non-condensable gaseous components such that the particulate matter is surrounded by and/or intermixed with a gaseous component containing 70-100% by volume of the condensable gas; and
forming briquettes in a briquette forming part of the briquetting apparatus, wherein briquettes are formed from the particulate matter under temperature and pressure conditions which cause the condensable gas to condense, thereby reducing gas pressure buildup during briquette formation and gas blow-back through the particulate matter being fed to the briquette forming part of the briquetting apparatus,
wherein the process further comprises using a precompactor to feed the partially dried particulate matter to the briquette forming part of the briquetting apparatus, and applying back pressure to said particulate matter using said precompactor and precompacted particulate matter to define a tortuous path to assist in further reducing blow-back of gases through the particulate matter being fed to the briquette forming part of the briquetting apparatus, wherein
the briquette forming part of the briquetting apparatus includes a pair of rollers through which the particulate bituminous matter passes, at least one of the rollers having pockets formed therein for assisting in

Assignees

• Tra Det Inc
• Commw Scient Ind Res Org
• K R Komarek Inc
• Griffin Coal Mining Company Pty Ltd

Inventors

• Clark Keith Norman
• Kalb George William
• Komarek Richard
• Meakins Ross Lawrence
• Pearson Arthur Clive

Classifications

• B30B15/308

  in a continuous manner, e.g. for roller presses, screw extrusion presses · CPC title

• B30B11/16

  using pocketed rollers, e.g. two co-operating pocketed rollers · CPC title

• C10L5/08 Primary

  without the aid of extraneous binders · CPC title

• C10L5/44 Primary

  on vegetable substances · CPC title

• C10L5/361

  Briquettes · CPC title