Abstract: A pollutant such as SO.sub.2 is removed from a pollutant-containing gas stream by passing the stream to a drying zone to which a solution and/or dispersion of pollutant-reactive material (such as CaO) is supplied, the drying zone operating to evaporate the liquid (e.g. water) and at least some pollutant reacting with the material to form an innocuous disposable solid which is removed, the pollutant-depleted gas stream being scrubbed in a scrubbing zone by a solution and/or dispersion of pollutant-reactive material to form substantially pollutant-free gas which is vented to atmosphere, the solution and/or dispersion being recovered from the scrubbing zone, some being recirculated back to the scrubbing zone after the addition of required make-up liquid and/or pollutant-reactive material, and some being passed to the drying zone preferably after concentrating the pollutant-reactive material therein. Preferably, the drying zone is a bed of solids fluidized by the incoming hot pollutant-containing gas stream.

Abstract: Fuel gas produced e.g. in a fluid bed gasifier and which comprises deposit-forming materials such as heavy hydrocarbons (e.g. tars) and non-combustible fines is passed via conduits and solid-removing cyclones to a burner for admixture with air and subsequent combustion. Deposits formed in the conduits cyclones and burner are removed by closing off the burner outlet and air inlet, and passing a deposit-removing reactant (e.g. air) into the conduit to oxidize and thereby remove deposits, particularly from the cyclones. Preferably, there are at least two burners for the fuel gas, and they are closed off alternately to remove deposits from their respective conduits and cyclones.

Abstract: Elementary sulfur is obtained from sulfur-containing materials which release sulfur oxides (SO.sub.x) in the presence of oxygen by fluidizing such materials in a bed with an oxygen-containing gas (e.g., air), and passing the resulting SO.sub.x -containing gases through a bed (preferably fluidized) of carbonaceous or carbon-containing solids (such as coke or coal) at an elevated temperature to reduce SO.sub.x to elemental sulfur, the bottom of the bed of carbonaceous or carbon-containing solids being at about the level of the top of the bed of sulfur-containing materials.

Abstract: Substantially sulfur-free combustible fuel gas under superatmospheric pressure is produced by partial combustion or gasification under superatmospheric pressure of a sulfur-containing solid, liquid or gaseous fuel. The gasification is effected within a fluidized bed of particles containing alkaline earth metal compounds (e.g. the oxides) which are capable of reacting with, and of fixing, the fuel sulfur as sulfides under reducing conditions. Sulfide-containing particles are exposed to an oxidizing atmosphere and the sulfides are thereby converted to oxides with the liberation of SO.sub.2 in useful concentrations, and with the liberation of heat. Particles containing regenerated oxides are re-used for fixing more sulfur during fuel gasification. Expedients are described by which it is ensured that the sulfur-fixing activity of the particles is substantially maintained and that the temperatures of the particles during sulfur-fixing and regeneration are maintained within predetermined ranges.

Abstract: A nozzle for uniformly distributing fluid from a high velocity and high pressure zone to a lower pressure and a relatively low velocity zone which comprises: an inner wall member that contains a plurality of orifices that communicate with an outer wall member containing a plurality of orifices, which are laterally offset from the orifices of the inner wall. The fluid is passing from the high pressure zone to the low pressure zone must impinge upon the outer wall and/or interact with the fluid in the area between the inner and outer walls to dissipate the energy from the fluid, in order to produce the lower velocity and pressure of the existing fluid.