AT376144B - DEVICE FOR COOLING, DESulphurizing and Reheating Smoke Gases - Google Patents

Description

  

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   The invention relates to a device for cooling, desulfurizing and reheating flue gases from thermal power plants.



   Several methods are currently used to remove the sulfur content of flue gases. In the so-called wet processes, the washing facilities achieve very high levels of desulfurization by adding lime or quicklime. The disadvantage of these wet washes is that the temperature of the flue gases is reduced to such an extent that they have to be reheated before reaching the fireplace. In order not to have to accept any avoidable heat losses when cooling in wet laundry, it is desirable to cool the flue gases as much as possible before entering the wet scrubber. The heat exchangers currently available for this, however, suffer from low-temperature corrosion.

   It is advantageous to use the heat extracted from the flue gas to heat an air stream which, after washing, then heats the cold flue gases to the desired chimney inlet temperature, optionally by admixing them.



   Attempts to reheat the cold, cleaned flue gases using regenerative preheaters fail because gypsum particles entrained by the washed flue gas adhere to the heating surfaces and lead to the heat exchanger being closed.



   All previously proposed solutions to this problem group have the additional disadvantage in common that they require long and fluidically unfavorable pipe connections and gas paths. This requires large floor space and high investment costs.



   The invention has set itself the task of creating a device for cooling, desulfurizing and reheating flue gases without the disadvantages described. According to the invention, this is done in that, preferably from bottom to top, an essentially prismatic or cylindrical regenerative preheater, a preferably identical wet washing system and a device for introducing hot air into the cleaned flue gas are aligned, advantageously in the lower, possibly underground part of a fireplace are.



   The arrangement of the components according to the invention and their connection with one another permits a compact and yet easily accessible construction.



   The invention is explained in more detail with reference to the drawing without being limited to it.



  It shows a device according to the invention in section. It is explained in the order in which the flue gas flows.



   A flue gas line --5-- which guides the hot, sulfur-containing flue gases opens into a heat exchanger --1--, in which the flue gases introduced give off part of their heat to air flowing in counterflow. This is fed in and out using lines --6, 7--. The flue gases then enter a desulphurization plant --2--, are desulphurized there, preferably using the wet process, and leave the desulphurization plant --2-- at the other
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 Bring a train to flow through the chimney. The arrangement of the heat exchanger of the desulfurization system and the mixing tube is accommodated in the lower part of a chimney --4--, aligned from bottom to top.



   The hot air can of course also be supplied to the mixing tube, deviating from the exemplary embodiment shown, by means of several, symmetrically arranged nozzles which are directed in such a way that they transmit an additional impulse in the flow direction to the flue gas.



   The heat exchanger-1-is preferably a regenerative heat exchanger which has ceramic internals or ceramic bulk material as the heat transfer material for reasons of corrosion.



  Synchronously rotatable, axially adjacent baffles on both sides of the heat transfer material separate the flue gas flow from the air flow, and permanently installed baffles in the area of the heat transfer material prevent mixing of the two gas flows.



   The desulfurization system is preferably a wet desulfurization system of a known type, in which a droplet veil of suitable chemical composition moves in countercurrent to the flue gas due to gravity and desulfurizes it.



   The invention is not limited to the embodiment shown, for example the supply lines and the discharge lines can be varied depending on the local conditions without leaving the field of the invention.

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   In order to save on the chimney height, the arrangement according to the invention can be set down into the ground. The individual parts of the arrangement do not have to be coaxial with one another.



  They can also be provided at an angle or partially next to one another. It is important to ensure a low flow resistance of the air and flue gas flows.



    PATENT CLAIMS:
1. Device for cooling, desulfurizing and reheating flue gases from thermal power plants, characterized in that, preferably in alignment and from bottom to top, an essentially prismatic or cylindrical regenerative preheater (1), a desulfurization system (2) of preferably the same design and a device ( 9) for introducing hot air into the cleaned flue gas are advantageously arranged in the lower, possibly underground part of a chimney (4).

 

Claims (1)

 2. Device according to claim 1, characterized in that the device (9) for introducing the hot air has a plurality of symmetrically arranged nozzles (3) which are directed such that the inflowing air transmits an additional impulse in the direction of flow of the flue gas to the latter.