DE3247680C2 - Rotor heat exchanger which is arranged between a raw gas duct and a clean gas duct of a wet flue gas desulfurization system - Google Patents

Abstract

In a method for operating a rotor heat exchanger (4) between the raw gas side and the clean gas side of a wet flue gas desulphurization system (8), hot raw gas is fed in one direction through a sector (5) of the heat exchanger and clean gas to be heated in the opposite direction through another sector (6) of the Out of the heat exchanger and rotates between and in the sectors a rotating body through which the gases flow. According to the invention it is provided that steam is passed through at least one cleaning sector (7) located between the raw gas sector (5) and the clean gas sector (6) and the steam (10) emerging from the heat exchanger (4) to the raw gas entering the flue gas desulfurization system (8) is admixed.

Description

3

non-desulphurized flue gases are over the raw In the embodiment shown occurs in the area

gas duct of the flue gas desulphurisation system of the cleaning sector 7 steam from below into the rotor set Compared to the previously used rotor heat exchanger one, d. H. in the same direction as that Exchangers without a cleaning sector become pure gas. The cleaning sector 7 on the top Slip towards the clean gas side allowing surfaces 5 of the rotor heat exchanger 4 leaving steam At least half the amount entering the flue gas desulfurization system 8 in the cleaning sector, the respective feed can be supplied to the raw gas via line 10 stand the heat exchanger surfaces in the rotating body between the raw gas line in front of the fan 3 and

respect, think highly of. the clean gas line after the rotor heat exchanger

The clean gas inlet and the steam io a bypass line 11 are preferably provided, input assigned to the same end face of the rotor. With the help of the ΚΙερ-

since there is a risk of deposits on the clean gas inlet pen 12, the raw side emerging from the dust filter can of the heat exchanger is the largest gas on the flue gas desulfurization system 8 and the

In order to distribute the solids, in particular the gypsum, bypass line 11 if possible, Wash off quickly after the deposit, at least 15 This depends on the amount in the steam generator 1 two separate cleaning sectors burn fuel and that for the steam generator provided, d. H. two official requirements in the circumferential direction of the rotor. If a complete heat exchanger spaced cleaning-up desulphurization of the raw gas is required, Sectors. To wash the heat accumulator, bypass line 11 and flaps 12 are no longer needed, 20 As already mentioned, instead of the one cleaning agent, it is also expedient that the steam induction sector 7 also has a plurality of circumferential ducts with a supply of solution additives, clean bundles arranged at a distance from one another are used Since the steam of the flue gas desulfurization sectors must be provided; z. B. can have two single system is supplied, these solution to each other diametrically opposite cleaning sector sets later also be provided in the flue gas desulfurizer, treatment system removed from the flue gases is usually between the steam generator

It is not necessary for the steam inlet duct and the dust filter 2 to have a rotor air preheater is continuously supplied with steam; switched on for the combustion air depending on the size. This is in the ße the load on the heat storage material, in particular the figure for the sake of simplicity has been omitted.

special the metal surfaces, is preferably provided

hen that the steam inlet duct in specified 1 sheet of drawings Steam can be applied at intervals

The invention will now be described on the basis of an exemplary embodiment shown in the accompanying figures will; it shows

F i g. 1 a circuit diagram with a rotor heat exchanger and

F i g. 2 Top view of the heat exchanger.

In the embodiment shown in FIG. 1, the raw gases leaving a steam generator 1 are fed to a rotor heat exchanger 4 via a dust filter 2, which is preferably an electrostatic filter, and a fan 3. Such rotor heat exchangers with their gas ducts are known per se and therefore do not need to be explained further here. In the embodiment shown the heat exchange enabling rotating body from rotating in a casing Aa. On the top and bottom of the housing 4a are gas supply channels and the covers (sector plates) arranged so that the rotating body from between a Rohgassektor 5, a clean gas sector 6 and a cleaning sector 7 rotates in FIG. 2, the channels and covers are only characterized by the webs extending from the center of the housing. The F i g. FIG. 2 is a plan view of the FIG. 1 is a schematically illustrated rotor heat exchanger 4, the crosses represent incoming raw gas and the dots represent exiting clean gas in sector 6 and exiting steam in cleaning sector 7. The flue gas entering raw gas sector 5 leaves the rotor heat exchanger and enters a wet flue gas desulfurization system 8, in which gypsum is produced from the SO2 contained in the flue gas using known processes. The clean gas cleaned in the flue gas desulphurization system enters the clean gas sector 6 from below and is heated there to the extent necessary for discharge via a chimney 9.

Claims (5)

1 2 It has already been proposed that these Ablagerun patent claims: gene by means of an insertable in the radial direction in the housing of the rotor heat exchanger and above the 1. Rotor heat exchanger that moves back and forth between a rotating body in the steam blower To remove raw gas duct and a clean gas duct at regular intervals in order to prevent the flue gas desulphurisation system from being baked on to the gas ducting openings in the storage unit and in which the ducts in the direction of rotation are made of the material of the heat exchanger. As a result of the rotor seen one behind the other a raw steam blowing is assigned to the plaster of paris from the Wärmetaugassektor and a clean gas sector, shear surface removed and occurs in dust or wasd characterized in that between io droplets of dissolved from the chimney. The pressure for the clean gas sector (6) and the raw gas sector (5) the vapor bubbles is limited in that from the at least one cleaning sector (7) is provided, so that the chimney does not have too much discharge. at The one with a steam inlet channel and one of the proposed methods can therefore not be used Steam outlet channel is connected, and that the avoid that when the steam generator comes to a standstill Steam outlet channel with the raw gas channel downstream 15 of the heat exchanger must be cleaned thoroughly. of the rotor heat exchanger is finally connected from DE-AS 12 44 326 a device 2. Rotor heat exchanger according to claim 1, data for wet cleaning of flue gases in connection characterized in that the clean gas inlet and known with a rotor heat exchanger in which the im Steam inlet of the same end face of the rotor to the rotor body of the rotor heat exchanger itself are essential. 20 borrowed proportions of sulfuric acid and sulfur dioxide 3. Rotor heat exchanger according to claim 1 or 2, to be divorced a To achieve this is a characterized in that at least two separate washings of the heat exchanger are required, Separate cleaning sectors are provided in order to cool the hot flue gas below the dew point in it. To achieve this, in addition to the heat 4. Rotor heat exchanger according to one of the claims 25-emitting zone and for the heat-absorbing zone before 1-3, characterized in that the steam zone is arranged a washing and cooling zone, which is from input channel with a supply of solution additive the heat storage material on the way from the zen is connected to the heat-emitting zone to the heat-absorbing zone 5. Rotor heat exchanger is passed after one of the claims zone. That way, that will already be before 1 - 4, characterized in that the steam, which is pre-cooled by the clean gas, can be acted upon by the Wa steam in front of the inlet channel at predetermined time intervals with enters the heat-absorbing zone. falling below the point in the heat-absorbing zone ne sure to reach. 35 It is the object of the present invention to create a rotor heat exchanger of the type mentioned, The invention relates to a rotor heat exchanger, which on the one hand at a comparatively higher temperature which can be cleaned between a raw gas duct and a clean gas duct and in the case of the other the nal a wet-working flue gas desulphurisation dissolved dirt in which the rotor heat exchanger is arranged and in which the pure gas leaving the channels in the rotating 40 essentially does not enter direction of the rotor seen one behind the other. This object is achieved in that between Raw gas sector and a clean gas sector are assigned. the clean gas sector and the raw gas sector at least Such a rotor heat exchanger is provided from DE-AS a cleaning sector is provided with a 60 845 known The rotating body has a storage steam inlet channel and a steam outlet channel material, e.g. B. is connected to closely spaced Me- 45 and that the steam outlet channel with the tall areas filled. During the rotary movement of the raw gas duct downstream of the rotor heat exchanger, raw gas is bound via the raw gas sector. passed through the storage material, while in the medium through the use of steam as a cleaning clean gas sector clean gas through the storage material, a dew point is passed in the bowl. As a result of the rotation, the raw material is avoided as much as possible while gas flow heated storage material in the sector through the connection of the steam outlet channel with the of the heat exchanger, through which the clean gas flow is fed raw gas duct downstream of the rotor heat exchanger and heats up the clean gas. The well-known is that an ejection of plaster and droplets Rotor heat exchanger is a wet working smoke from the chimney, to which the smoke gases are fed, assigned to a gas desulphurisation system, in which the waste 55 is reduced quite considerably. In the case of the rotor heat exchanger cooled according to the invention with an absorbent solution, the rotating body can trickle into it. The at the bottom of the sprinkler tower are cleaned thoroughly, so that longer times between accumulating rich solution will be obtained in an expeller which can be inspected individually. Because it transferred, in which the absorbed sulfur dioxide is only driven out in the rotating body of the heat exchanger. 60 very small deposits can occur, the With newer wet-working flue gas desulphurisation pressure loss across the heat exchanger is reduced systems, calcium hydrate is formed. and thus reduces the fan work required, I; In these systems, the cold clean gas flow is used to guide the gases through the heat exchanger |; water droplets with solids dissolved therein are still required, d. H. the electrical consumption of the included, so that at least on the clean gas inlet side 65 power plant is reduced. Through the cleaning of the heat exchanger deposits on the heat exchanger, the slippage of non-desulphurised raw shear metal surfaces will occur. These solids consist of gas to the clean gas side considerably reduced because those of II essentially made of plaster of paris and must be removed. crossing the raw gas side into the cleaning sector