SE447598B - PROCEDURE FOR FINAL COMBUSTION OF BED MATERIAL FROM A FLUIDIZED BED COMBINATION PLANT - Google Patents

Description

447 598 from a fluidized bed gasification or combustion plant.

For this purpose, the invention is characterized in that the secondary reactor is supplied with combustion and / or fluidizing gas from the inlet with a pressure corresponding to the pressure drop across the nozzle bottom, that ash and bed material are automatically drained immediately above the nozzle bottom and led into the secondary reactor. column in this, corresponding to said pressure drop across the nozzle plate and that the fluidizing / combustion gas heated in the secondary reactor of the bed material is led to the combustion chamber.

The walls of the secondary reactor are suitably cooled.

The invention will be described below with reference to the accompanying drawing, which schematically shows a fluidized bed combustion plant and a device according to the invention.

The combustion plant comprises a primary reactor 10 with combustion chamber 11, to which fuel and bed material are fed by means of a plug-forming screw conveyor 12. Combustion and fluidizing gas is supplied to the lower part of the combustion chamber via a channel 13 and an inlet 14. A nozzle bottom 11a forms substrate for the bed material-fuel and distributes the flow of fluidizing and combustion gas therethrough.

A smaller, secondary reactor 15 is arranged next to the primary reactor 10 and is connected to it via an inlet line 16, an outlet line 17 and a material transport line 18.

The inlet line 16 is connected to the inlet 14 for combustion and fluidizing air, via a valve 19, which enables regulation of the branched gas flow, which enters a distribution chamber 20. h The outlet line 17 connects the upper end of the secondary reactor to the combustion chamber 11a above the primary reactor.

The material transport line 18 forms a substantially downwardly directed channel, which opens just above the nozzle bottom 11a. '447 598 Excess bed material flows through this channel from the primary reactor and is fluidized at low speed in the secondary reactor. Thereby, residual fuel residues in the bed material are final combusted and the heat energy is absorbed by the fluidizing gas.

Final combusted bed material is drained from the secondary reactor 15 via a bottom valve 21. New material then flows in from the primary reactor 10, so that a quantity of material is automatically maintained in the secondary reactor, which amount forms a fluidized column corresponding to the pressure drop across the distribution plate 11a in the primary reactor. The length of the secondary reactor tube is increased by a margin, so that this column height can be maintained. The fluidizing gas heated in this way in the secondary reactor is led via the outlet line 17 to the primary reactor 10 and serves as fluidizing gas therein. The heat energy in the incineration plant's waste material is thus utilized as a heat addition to the incineration process of the primary reactor 10, which gives a higher efficiency in the plant.

The walls of the secondary reactor can be cooled for more efficient cooling of the bed material. For this purpose, cooling surfaces can also be arranged in the bed of the secondary reactor, which cooling surfaces are passed through by external cooling medium, e.g. air, gas or water.

The invention is not limited to the exemplary embodiment described above, but several variants are conceivable within the scope of the appended claims.

Claims (2)

447 598 PATENT REQUIREMENTS A method of final combustion of combustible bed material from a gasification or combustion plant comprising a fluidized bed, an inlet (14) for combustion and / or fluidizing gas located in the lower part of the combustion chamber (II) and a nozzle located above it. bottom (11a) for distributing the combustion or fluidizing gas in the bed and wherein the combustion plant is connected to a secondary reactor (15) with significantly smaller cross-section than the combustion plant (10), which is connected to it via: one connected to the inlet (14) inlet line (16) for fluidizing / combustion gas, an outlet line (17) connected to the combustion chamber (ll) for greased fluidizing / combustion gas and a material transport line (18) for supplying ash and bed material and a valve (21) for reducing final combustible material, characterized in that the secondary reactor is supplied with combustion and / or fluidizing gas from the inlet (14) with a tt pressure corresponding to the pressure drop across the nozzle bottom (11a), that ash and bed material are then automatically drained immediately above the nozzle bottom (11a) and led into the secondary reactor * (15), to maintain a fluidized column therein, corresponding to said pressure drop across the nozzle plate (11a). 11a) and that the fluidization / combustion gas heated in the secondary reactor of the bed material is led to the combustion chamber (11). IN Process according to Claim 1, characterized in that the walls of the secondary reactor (15) are cooled.