Process for producing smokeless, cured fuel briquettes
AssigneePetrofina, U.K. Ltd.
InventorsPeter R. McCrainor, Peter B. Caplin, James W. Middlemas, Geraint Rees, Mario Angelini
Life of this patent
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Abstract
Green briquettes made from particulate carbonaceous material and lignosulfonate as a binder are cured in an oven in the presence of circulating gases containing a high percentage of oxygen and superheated steam. The sulfur derived from the binder is oxidized and then hydrolyzed (exothermic reactions) at the curing temperature with formation of sulfuric acid, which is dissociated (endothermic reaction) in the case of a temperature rise. The reactions provide a means for thermal balance within the curing oven.
Claims20
A process for producing smokeless, cured fuel briquettes comprising the steps of:
- (a) forming green briquettes from a particulate carbonaceous material and a lignosulfonate binder;
- and
- (b) curing said green briquettes in an oven in the presence of circulating gases containing a high percentage of oxygen and superheated steam, wherein the sulfur derived from said lignosulfonate binder is oxidized and hydrolyzed exothermally at the curing temperature forming sulfuric acid which is dissociated endothermally in case of a temperature rise above a threshold thereby promoting thermal balance within the curing zone, any remaining small excess amount of heat is removed in the circulating gases.
A process for producing smokeless, cured fuel briquettes comprising the steps of:
- (a) forming green briquettes from a particulate carbonaceous material and a lignosulfonate binder;
- (b) preheating said green briquettes by progressively increasing the temperature of said green briquettes up to about the oxidation temperature while evaporating the residual moisture;
- (c) curing the briquettes from step (b) in an oven in the presence of circulating gases containing superheated steam and at least 17% oxygen, wherein the sulfur derived from said lignosulfonate binder is oxidized and hydrolyzed exothermally at the curing temperature forming sulfuric acid which is dissociated endothermally in case of a temperature rise above a threshold thereby promoting thermal balance within the curing zone, any remainig small excess amount of heat being removed by injecting supplementary air and removing the excess heat in the circulating gases;
- and
- (d) precooling said briquettes from step (c) in a precooler stage then cooling the briquettes down to below about 100.degree. C.
A composition comprising smokeless, cured fuel briquettes produced according to the process comprising the steps of:
- (a) forming green briquettes from a particulate carbonaceous material and a lignosulfonate binder;
- and
- (b) curing said green briquettes in an oven in the presence of circulating gases containing a high percentage of oxygen and superheated steam, wherein the sulfur derived from said lignosulfonate binder is oxidized and hydrolyzed exothermally at the curing temperature forming sulfuric acid which is dissociated endothermally in case of a temperature rise above a threshold thereby promoting thermal balance within the curing zone, any remaining small excess amount of heat is removed in the circulating gases.
A process for producing smokeless, cured fuel briquettes comprising the steps of:
- (a) forming green briquettes from a particulate carbonaceous material and a lignosulfonate binder;
- and curing said green briquettes in an oven in the presence of circulating gases containing a high percentage of oxygen and superheated steam, wherein the sulfur derived from said lignosulfonate binder is oxidized and hydrolyzed exothermally at the curing temperature forming sulfuric acid which is dissociated endothermally in case of a temperature rise above a threshold thereby promoting thermal balance within the curing zone, wherein excess heat is removed in the circulating gases.
Dependencies are inferred from the claim text.