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.

Abstract: The specification describes arrangements in which the attemperation or control of the temperature of a fluidized bed in a fluidized bed combustion unit effected by means of the mixture of a variable proportion of inert gas with fluidizing air fed to the bed may be supplemented with steam. Supplementation with steam being effected to a relatively minor extent during normal operation of the unit but being effected to a major extent when the temperature of the bed passes outside the range at which attemperation may be effected by use of recycled flue gas. The combustion unit is described in use within an arrangement including process plant in the form of a rotary drum dryer.

Abstract: A combustible gas producer plant is described in which a finely divided inert particulate material fluidized bed is divided into a first, combustible-gas producing section and a second, heating section, to both of which sections fuel is fed. Heat transfer, by bed material migration, from the second to the first section sustains the reaction in the first section leading to the production of combustible gas. A diaphragm water wall divides and surrounds the volumes above bed sections and is part of a boiler generating steam used (optionally with added oxygen) to fluidize the first bed section. The steam is also used to fluidize the bed material at the boundary of the bed sections and prevent in-bed gas migration across that boundary. The second section of the bed is fluidized with air or an air/inert gas mixture. Fluidization is effected with sparge tubes and the plant may include evaporator, superheater and economizer sections for the boiler.

Abstract: The specification describes a method and means for controlling operation of a fluidized bed combustion apparatus. In the proposals embodied in the invention the supply of combustion air fed to the fluidized bed is augmented by inert gas (preferably waste gas taken from a low temperature outlet of the apparatus) and the proportion of inert gas used to augment the combustion supporting air is variable in dependence upon the temperature of the fluidized bed in the apparatus and/or the thermal demand placed upon the apparatus. In described embodiments of means enabling the invention to be effected arrangements are described including an induced draft fan, coupled to the outlet for waste gas of the apparatus, for feeding waste gas to a mixer and the use of a two input mixer fan coupled to both atmosphere and a waste gas supply line connected to a waste gas outlet.

Abstract: A boiler having a firebox in which combustion of fuel fed thereto is initiated, a flame tube leading from the firebox in which combustion of fuel may continue and an array of smoke tubes through which the products of combustion issuing from the flame tube are fed to a chimney. The surfaces of the firebox, flame tube and smoke tubes are surrounded by a chamber containing a heat transfer medium, peferably water. A superheater in which steam generated in the chamber is superheated may be included. The superheater is preferably located at the end of the flame tube.

Abstract: In an injector for supplying gas into a fluidized bed, a distributor having a plurality of spaced elements located within a particulate material forming a fluidized bed to extend generally transversely therein.