GB805832A - Improvements in the manufacture of fuel briquettes - Google Patents

Abstract

805,832. Carbonizing fuel briquettes; material for making coke. GAS COUNCIL. Feb. 1, 1955, No. 3011/55. Classes 55 (1) and 55 (2). A process for carbonizing fuel briquettes comprises passing a current of hydrogen or a gas containing at least 50 per cent hydrogen under a pressure well above atmospheric pressure, e.g. 10-25 atmospheres, through a charge of carbonizable briquettes, and reaction between the hydrogen and carbonaceous material of the charge is initiated by local supply of heat to the charge close to the place of admission of the gas and such supply of heat is then discontinued or suitably reduced, so as to cause a zone of reaction and high temperature to travel through the charge whereby the briquettes are carbonized. The local supply of heat may be provided by temporarily preheating the hydrogen or gas containing hydrogen, e.g. to 600 ‹C. The maximum temperature attained may be controlled by adjustment of the hydrogen content of the hydrogenating gas employed and the temperature attained may, for example, be lowered by diluting the gas with methane. A substance more readily reactive with hydrogen than the carbonaceous material of the briquettes may be admixed with the briquettes before treatment. Thus, e.g. a hydrocarbon oil of low volatility such as a high boiling coal tar oil may be sprayed on to the briquettes before carbonization. Alternatively a catalyst, such as sodium carbonate or calcium hydroxide, may be added to the briquettes to promote hydrogenation. The voids between the briquettes may be filled with a solid carbonaceous material which is preferentially hydrogenated, for example, a semi-coke or a coal. The hydrogenated residue from this added carbonaceous material may be recovered and briquetted for treatment by the process of the invention. The reaction may be effected in a series of vessels of the kind shown in Fig. 1 of Specification 519,246, and, after having initiated the reaction in one vessel by extraneous heat, and when the reaction in that vessel is complete, the reaction in a second vessel is initiated by passing in hot gas from the first vessel. Alternatively a single vessel may be operated continuously. In an example 30 parts of a weakly caking coal, 60 parts of a carbonaceous residue obtained by partial hydrogenation of a similar coal by the process of Specification 695,192, and 7 parts of a medium soft pitch are finely crushed, warmed to 80- 90‹ C. and briquetted under a pressure of 3 tons. A charge of these briquettes was carbonized by treatment with a gas containing 95 per cent of hydrogen under 50 atmospheres pressure and temporarily preheated to 600‹ C. A zone of reaction having a temperature of 950- 1000‹ C. travelled through the mass of the briquettes.