DE4142813A1 - Regenerative removal of sulphur@ from process gases - Google Patents

Abstract

Regenerative removal of sulphur@ from process gases by contact with particulate absorbent fluidised bed, sepg. adsorbent and bound sulphur from gas before sepg. adsorbent, etc.

Description

The invention relates to a method for brisk Native desulphurization of process gases using a circulating mass, in which process low-sulfur gases with a fluidized bed particulate absorbent in contact brings and to bind the sulfur to the absorber bens together with the absorbent through a Reaction zone and the absorbent that Has bound sulfur, is separated from the process gas, which is directed to further processing, after which the Absorbent that has bound sulfur to separate the Sulfur directed from the absorbent to regeneration the sulfur separated from the absorbent becomes white Therapy is conducted and the desulfurized Absorbent again in contact with the process gas is brought.

The invention further relates to an arrangement with a desulfurization reactor that has a vortex layer chamber in which one is made of a particulate Absorbent existing fluid bed is and into which a process gas is fed, a reactor mer above the fluidized bed chamber, separating agent in the upper part of the reactor chamber to separate the absorber of the process gas, one that has bound sulfur Discharge channel for discharging the process gas, one Regeneration reactor, at least one delivery channel to Directing the absorbent that has bound sulfur into the regeneration reactor, a channel for discharging the Regeneration gas and the separated sulfur from the Regeneration reactor and a return channel to bring it back absorbing from the bottom of the regeneration reactor in the fluidized bed.  

The central problem with direct ties of sulfur, e.g. B. calcium-based decongestants felungsverfahren is that a large amount Waste arises. Because the water-soluble ver binding of the waste generated creates a risk for the Form groundwater from dump sites, it is clear that processes developed over a long period of time the need to minimize the amount of waste generated lubricate.

Today there are also numerous procedures for bin of sulfur oxides, according to which the end valid bond as elemental sulfur of the solid Phase takes place. In principle, as an intermediate phase of all such processes first the content of the sweat field oxides are enriched high enough for the Elementary sulfur manufacturing process economically can be made mix profitable. When handing over tion process, the sulfur oxides are first turned on Absorbent bound with suitable properties, that is regenerated, the sulfur being released and an absorbent capable of binding the sulfur stands. The binding of sulfur and regeneration of absorbent, sulfur bound has, in separate reactors, between which the Absorbent is moved so that the absorbent, the Has bound sulfur in the regeneration reactor and accordingly the regenerated absorbent in the sweat Field binding reactor is promoted during the fermentation gas from the reactor and the sulfur separately be removed from the regenerator. The dislocation of the absorbent should be stable and done in a way that gas connections between the reactors in gerin to be mixed according to dimensions.

Currently on the fixed layer and Fluid bed technology based arrangements for Aus  management of regenerative sulfur binding processes developed. Because temperature control at regenerati desulfurization is very important, see the poss Promising possibilities of the fixed layer technology out because the heat control and the reaction control le are difficult to master. For an efficient material promotion it would also be important that a finely divided absorbent could be used which is difficult in a fixed bed reactor. To the Er sufficient circulation mass and separation box sufficient space is required, which is why the diameter of the fluidized bed technology-based reactors get big. Because the However, the amount of gas in a regeneration reactor is typically only 1-3% of the gas flow from a sulfur binding reactor the problem closes with the increasing Diameter primarily to the sulfur binding reactor.

The object of the present invention is to achieve this based on a method and an order bring, by means of which the disadvantages mentioned above can be avoided. The inventive method Ren is characterized in that the process gas separate absorbent, which has bound sulfur, abge is cooled before it both regulates the temperature the circulating mass and the reactor for regeneration tion is conducted.

The arrangement according to the invention is thereby ge indicates that the reactor chamber is a smaller one Has cross-sectional area in the gas flow direction than that Fluidized bed chamber and that in which the absorbent, the sulfur has bound in the regeneration reactor conductive conveyor channel a heat exchanger for control the temperature of the absorbent and thus the tempera structures of the entire reactor is provided.

In the method according to the invention  Sulfur binding in a circulating mass reactor instead, where it is possible to use a finely divided absorber bens, such as metal oxides or preferably any alloy metal oxide, such as zinc ferrite oxide (⌀ 0.05-0.3 mm), and a moderate gas velocity (3-6 m / s) to be used, the diameter of the Sulfur binding reactor does not become excessively large. At Using a bubble-forming fluidized bed technique it would be necessary to change the gas velocity at the be rapid absorbent size at a speed limit below 0.5 m / s. The Rege's gas flow nerierreactor is typically only 1-3% of the gas stream of the sulfur binding reactor, which is why the diameter of the regeneration reactor does not become large, although the Gas speed on the area of the bubbles forming fluidized bed is restricted, d. H. on the Speed of about 1 m / s.

A stabilization of the temperature of the sweat field binding reactor happens after the essential Idea of the invention by attaching cooling surfaces the circulation mainly in the return or circulation channel mass, being a festival flowing through a cooler material flow and thus the performance of the cooler depending on automatically regulates the gas flow to be treated will. If necessary, the temperature can be added by using a separate recycle gas stream to Rules of the performance of the cooler can be checked.

The nature of the invention is also essential how the solid flows between the reactors con be trolled. This is done using so-called Im pulse generator done, its working principle as follows is: at the beginning of a pulse generator one will graft like layer, d. H. a fixed layer zone, arranged net, from whose lower part solid pneumatic, in front preferably by means of pulsed gas supplies  is changed. A controlled circulation of the solid between the sulfur binding reactor and the rain Rierreaktor is by connection of the desulfur tion reactor by means of a pulse generator with the Re generation reactor and vice versa.

In the following the invention is described with reference to the accompanying drawings explained in detail. It demonstrate:

Fig. 1 and 1a schematically and to run mass reactor according to the invention (KM reactor)

Fig. 2 partially cut another embodiment of the inventive circulating mass reactor.

The circulating mass reactor according to the invention of the figure has a sulfur binding reactor with a nozzle bottom 1 through which a gas to be treated and a possible circulating gas are passed into a fluidized bed chamber 2 in the lower part of the circulating mass reactor. The lower part of the reactor, ie the Wirbelschichtkammer 2 , preferably has a larger transverse area in the gas flow direction than a egg actual reactor chamber 3 above. It is possible to maintain a large particle density in the lower part without increasing the particle density of the entire reactor space excessively. In the ring-shaped reactor chamber 3 of the figure, the gases and an absorbent as a suspension in the reactor move upward and come to a wing grille 4 of a cyclone in the upper part of the circulating mass reactor, the wings acting as a separating means and flow guide. Here, the suspension is passed tangentially into a cyclone chamber 5 , in which the absorbent particles separate from the gas. The gas purified from the particles is passed through a discharge channel in the middle of the cyclone, ie through a tube 6 , for further treatment and the amount of particles separated on the walls of the cyclone falls into a distribution chamber 7 below an intermediate plate 21 . The task of the distribution chamber 7 is to distribute the circumferential particle mass evenly over the entire transverse surface of a preferably axially symmetrical cooler part located in the center of the ring-shaped reactor chamber, ie a heat exchanger 9 . This is brought about by means of a nozzle plate 8 which is shaped in a suitable manner. Fig. 1a shows schematically a cross section of the reactor at position AA, from which it can be seen how the reactor is shaped. The principle of operation of the heat exchanger in the middle of the reactor is recuperative. The heat exchanger 9 has a plurality of return channels or heat transfer channels 9 a, through which the circulating mass returns through the cooler 9 in its lower part. In between, a space is provided from which coolant, such as gas, air, water, any other liquid or steam, flows against the direction of flow of the circulating mass from the lower part of the cooler through a channel 11 in its upper part and the outer surface of the channels 9 a and thus the circulating mass flowing in it cools down.

To guide the gas flow of the Umlaufmassenreak tors a bottom cone 10 is arranged at the lower end of the cooler 9 , the free area is at most 10% of the transverse surface of the annular space 3 . With reference numerals 11 and 12 , input and output channels of the cooling gas stream coming into the cooler or any other medium stream are referred to.

In Fig. 1, a regeneration reactor 13 is arranged in a ring around the sulfur binding reactor 3 . Reference numeral 14 denotes input connections of a regeneration gas, such as water vapor or another suitable gas, reference numeral 13 relates to an annular regeneration chamber and reference numeral 20 denotes a connector of a sulfur-containing gas flowing out of the regeneration. From the lower part of the heat exchanger 9 leads into the upper part of the regeneration reactor 13 a delivery channel, ie a tube 16 , which has a vertical starting part 15 at its end adjoining the cooler 9 , to which the sorbent which has bound sulfur has a graft-like layer forms. This is followed by a horizontal gas channel 19 , which is located at the corner of the tube part 16 and forms an extension thereof, through which channel a carrier gas is preferably supplied in a pulsed manner, which carrier gas has the absorbent which binds sulfur through the tube 16 promotes in the regeneration reactor 13 . The reference sign 17 denotes a connected to the lower part of the regenerating reactor return channel of the regenerated absorbent, which at the beginning has a vertical part on which the regenerated absorbent forms a second plug-like layer, from which the sorbent from one through a connection 18 again preferably pulse-fed gas is fed into the sulfur binding reactor. The serving as a seal, plug-like solid layer is brought about by the fact that solid material can flow into the substantially vertical pipe 15 or 17 of the conveying channel, in which the surface of the solid material is held high enough above the horizontal part of the conveying pipe. If no gas is passed through the connection 19 or 18 into the delivery pipe, the flow of solid stops because the solid is unable to flow by itself in the substantially horizontal delivery pipe.

When gas is supplied to the delivery pipe, it catches Absorbent layer of the vertical pipe, graft to flow downward well, while the lowest part away from it with the gas, its gas tightness is obtained. At the bottom of the vertical pipe part becomes a conveyor pipe for fixed substance connected in which the solid pneuma table, using a suitable carrier gas either by means of a continuous gas flow or gas impulses is promoted.

In the sulfur binding reactor, the typical gas velocity for the entire transverse surface 3 varies between 3 and 6 m / s. The suspension density in the lower part of the sulfur binding reactor is most preferably in the range 50-300 kg / m ³ and in the upper part in the range 5-30 kg / m ³ . The temperature range is determined according to the chemical kinetics of the binding reaction and typically varies in the range 450-1050 ° C. It is essential that the temperature can be adjusted to a desired value in the entire volume of the binding reactor by using the circulating mass technique.

Compared to the gas stream of the sulfur binding reactor, the gas stream in the regeneration reactor is very small and a very low gas velocity can be used smoothly without significantly increasing the external dimensions of the arrangement. An arrangement-technically advantageous solution is to mount the regeneration reactor rotationally symmetrically according to FIG. 1 around the sulfur binding reactor. When using a finely divided absorbent, the suitable gas velocity in the regeneration reactor is 0.2-1.0 m / s. The average density of the suspension zone of a fluidized bed reactor which functions in a bubble-forming state is most preferably 100-500 kg / m ³ .

The temperature is based on the rate of regeneration reaction determines and varies in the range 700-1300 ° C. The temperature range of the regeneration reactor is at most of the absorbents pretty narrow, being it must be possible, including the temperature of the regeneration to regulate the reactor precisely. Because the released heat Meenergy is relatively small, the fine can setting the temperature with a direct, on Evaporation based processes can be performed. In most cases, water is the most beneficial Coolant.

Fig. 2 shows another embodiment of the reactor according to the invention schematically, partially cut away. The actual desulfurization reactor is shown on the right in FIG. 2, in which gases containing sulfur are passed through a channel 1 into the reactor. From this they flow further into a fluidized bed chamber 2 , in which they flow through fluidized bed material and continue along an annular channel 3 into the upper part of the reactor, from which they turn from a flow conductor 4 , ie a wing grid, controlled into a separation chamber 5 , in which separates the circulating mass, ie the absorbent that has bound sulfur, from the gases. The gases are removed in the manner shown in Fig. 1 through a channel 6 in the middle of the separation chamber 5 and the absorbent falls down from the separation chamber through a circulation channel 5 a back into the chamber 2 . A part of the absorbent falls into a vertical discharge duct 15 and out of it further into a horizontal part 16 of the discharge duct, from which it is conducted into the regeneration reactor by means of a carrier gas supplied from a duct 19 . The regeneration reactor works in principle in the same way as the desulfurization reactor, with regeneration gas and / or steam being passed through a channel 14 in the lower part of the regeneration reactor, the regeneration gas and / or the steam coming into a chamber 13 ', preferably a Fluid bed chamber is, and along the ring-shaped part, ie along a regeneration chamber 13 a, flows further into the upper part of the reactor and again controlled by a vane grate 4 'in a separation chamber 5 '. The absorbent regenerated in the separation chamber separates from the regeneration gas and steam which carries the sulfur with it as it moves away through a channel 20 in the middle of the chamber. The in the chamber 5 'separate absorption medium falls further through a second circulation channel 5 a' down into the chamber 13 'back to come into contact with the regeneration gas or steam. However, part of the regenerated material falls back into a return channel, ie a pipe 15 ', and further into a horizontal part 17 in its lower part, which part along regenerated sorbent by supplying a carrier gas through a channel 18 into the chamber 2 of the Desulfurization reactor is passed, which carrier gas carries the Absorbentsmit tel with it. In the solution of FIG. 2, heat exchangers are attached both to the horizontal conveying channel leading from the desulfurization reactor into the regeneration reactor, ie the pipe 16 , and to the return channel of the absorbent, ie the pipe 17 . In a heat exchanger 21 around the För derkanal 16 coolant is passed through a connection 22 , and it is removed by a connection 23 ent, ie the heat exchanger works according to the countercurrent principle. Accordingly, coolant is passed into a heat exchanger around the return channel 17 through a connection 22 ', and it is also removed according to the countercurrent principle through a connection 23 '. Fig. 2 shows both the Ent sulfurization reactor and the regeneration reactor heat exchanger or cooler 24 and 24 ', is passed through the heat transfer medium via compounds 11 , 11 ' and 12 , 12 '.

The invention is described by way of example only above in the description and the drawings, and is in no way limited to this. In addition to a reactor solution constructed as a unit and a solid unit, separate solutions can be used in the manner shown in FIG. 2 , the desulfurization reactor being designed as efficiently as possible for the desulfurization and the regeneration reactor being constructed differently, as efficiently as possible, expressly for the regeneration can be.

Claims (16)

1. A process for the regenerative desulfurization of process gases by means of a circulating mass, in which process sulfur-containing gases are brought into contact with a particulate absorbent which forms a fluidized bed and are passed through a reaction zone together with the absorbent to bind the sulfur to the absorbent, and the Ab sorbent which has bound sulfur is separated from the process gas which is passed for further treatment, after which the absorbent which has bound sulfur is passed to separating the sulfur from the absorbent for regeneration, the sulfur separated from the absorbent is passed for further treatment and that Desulfurized absorbent is brought back into contact with the process gas, characterized in that the absorbent separated from the process gas, which has bound sulfur, is cooled before it is passed to regulate the temperature of both the circulating mass and the reactor for regeneration. 2. The method according to claim 1, characterized in that the cooling is carried out by means of a heat exchanger ( 9 , 21 ) which is attached in a circulating mass for regeneration conductive channel that a plug-like layer of circulating mass for regulating the gas flow on a delivery channel ( 15 is formed, 16), in that absorbent is conveyed by means of guided into the conveying channel (16) gas impulses from the group formed by the plug layer in a Regenerierreaktor (13), and that in the Un terteil of Regenerierreaktors (13) has a second plug-like layer of regenerated Absorbent is formed, which is conveyed from the second plug-like layer into the fluidized bed by means of gas pulses directed into a return channel ( 17 ). 3. The method according to claim 1 or 2, characterized in that the flow of the circulating mass through the heat exchanger ( 9 ) is regulated in that a suitable circulating gas or the like is passed into the fluidized bed. 4. The method according to claim 2 or 3, because characterized by that particle material of at least two different levels of rudeness classes to bring about a suitable suspension ion density in the fluidized bed is used where the coarser particle material has a diameter of 0.5-2 mm and the circulating mass flows mung is formed by a material that a much smaller diameter, preferably 0.05-0.3 mm, Has. 5. Method according to one of the preceding Pa tent claims, characterized, that the sulfur binding absorbent consists of at least a metal oxide or alloy metal oxide is. 6. Arrangement for carrying out the method according to claim 1, which arrangement includes a desulfurization reactor which has a fluidized bed chamber ( 2 ) in which a fluidized bed consisting of a particulate absorbent is located and into which a process gas is passed, a reactor chamber ( 3 ) above half of the fluidized bed chamber ( 2 ), separating means in the upper part of the reactor chamber ( 3 ) for separating the absorber which has bound sulfur from the process gas, a discharge channel ( 6 ) for discharging the process gas, a regeneration reactor ( 13 ), at least one conveyor channel ( 15 , 16 ) for guiding the absorbent which has bound sulfur into the regeneration reactor ( 13 ), a channel ( 20 ) for discharging the regeneration gas and the separated sulfur from the regeneration reactor ( 13 ) and a return channel ( 17 ) for returning the absorbent from the lower part of the regeneration reactor ( 13 ) in the fluidized bed, characterized in that the reactor chamber ( 3 ) has a smaller transverse area in the gas flow direction than the fluidized bed chamber ( 2 ), and that in which the absorbent, which has bound sulfur, in the regenerating reactor ( 13 ) conducting conveying channel, a heat exchanger ( 9 , 21 ) for regulating the temperature From sorbent and thus the temperatures of the whole reactor is provided. 7. Arrangement according to claim 6, characterized in that the fluidized bed chamber ( 2 ), the reactor chamber ( 3 ) and part of the absorbent in the regeneration reactor conductive conveyor channel ( 15 , 16 ) are formed substantially coaxially cylindrical, so that the absorbent in the regeneration reactor conductive part ( 15 ) of the delivery channel is located above the fluidized bed chamber ( 2 ) substantially axially therewith, and that the reactor chamber ( 3 ) is formed into an annular channel around the delivery channel that in the upper part of the reactor chamber ( 3 ) a cyclone chamber ( 5 ) is provided, at the upper end of which flow conductors ( 4 ) are attached, so that the suspension consisting of process gas and absorbent tangentially towards the center of the cyclone chamber ( 5 ) rich tet that the discharge channel ( 6 ) in The center of the cyclone chamber ( 5 ) is coaxial with it, the process gas being removed through the discharge channel ( 6 ) and the absorbent in a distribution comb he ( 7 ) falls below the cyclone chamber ( 5 ) and therefrom at least partially further into the part ( 15 ) of the delivery channel, which is located below the distribution chamber ( 7 ). 8. Arrangement according to claim 7, characterized in that the heat exchanger ( 9 ) is formed substantially coaxially with the fluidized bed chamber ( 2 ) in the delivery channel above the fluidized bed chamber ( 2 ) that the delivery channel has a plurality of heat transfer channels running through the heat exchanger, by which flows the absorbent, the sulfur bound, and the outer surface of which is cooled by a coolant flowing through the heat exchanger ( 9 ). 9. Arrangement according to claim 8, characterized in that the regeneration reactor tor ( 13 ) is ring-shaped around the reactor chamber ( 3 ) angeord net. 10. Arrangement according to claim 7, characterized in that the regeneration reactor ( 13 ) is a separate reactor into which the absorbent reacted with the sulfur is passed and from which the regenerated absorbent is fed back into the fluidized bed chamber ( 2 ) of the desulfurization reactor , and that the desulfurization reactor has a circulation channel ( 5 a) around the delivery channel ( 15 ) of the absorbent substantially coaxially therewith, so that part of the absorbent is returned directly into the fluidized bed chamber ( 2 ). 11. Arrangement according to claim 10, characterized in that the regeneration reactor gate ( 13 ) has a second fluidized bed chamber ( 13 ') in which there is a fluidized bed consisting of a particulate absorbent and into which the generating gas is passed, one above the second Fluidized bed chamber ( 13 ') located Regenerierkam mer ( 13 a), which has a smaller transverse area in the flow direction of the regeneration gas than the second fluidized bed chamber ( 13 '), release agent in the upper part of the regeneration chamber ( 13 a) for separating the regenerated absorbent from Regeneration gas and a line from ( 20 ) of the regeneration gas and a return channel ( 15 ', 17 ) for returning the regenerated th absorbent from the lower part of the regeneration reactor ( 13 ) in the fluidized bed of the desulfurization reactor ( 13 ). 12. An arrangement according to claim 11, characterized in that the second fluidized bed chamber (13 '), the regeneration chamber (13 a) and the part of the regenerated absorbent in the fluidizing chamber (2) of the desulfurization direct the return channel (15') substantially coaxially are cylindrical, so that the part of the absorbent in the desulfurization reactor conducting back channel ( 15 ') is above the second fluidized bed chamber ( 13 ') so that the regeneration chamber ( 13 a) formed into an annular channel around the back channel ( 15 ') is that in the upper part of the regeneration chamber ( 13 a) there is a second cyclone chamber ( 5 '), at the top end of which flow conductors ( 4 ') are provided so that the Sus pension consisting of regeneration gas and absorbent tangentially against the center of the second cyclone chamber ( 5 ') directs that the discharge channel ( 20 ) is in the middle of the second cyclone chamber ( 5 ') coaxially therewith , wherein the regeneration gas and the separated sulfur are removed through the discharge channel ( 20 ) and at least part of the regenerated absorbent falls into the return channel ( 15 ') below the second cyclone chamber ( 5 '). 13. Arrangement according to claim 12, characterized in that around the return channel ( 15 ') of the absorbent substantially coaxially therewith a second circulation channel ( 5 a') is provided, namely for returning part of the absorbent into the second fluidized bed chamber ( 13 ') . 14. Arrangement according to one of the claims 10-13, characterized in that we at least one heat exchanger ( 21 ) in which lead from the Ent sulfurization reactor into the regeneration reactor, which acts as a delivery duct ( 16 ) is mounted. 15. Arrangement according to one of the claims 10-14, characterized in that we at least one heat exchanger ( 21 ') in the lei from the regeneration reactor in the desulfurization reactor, acting as a delivery channel tube ( 17 ) is installed. 16. Arrangement according to one of claims 6-15, characterized in that at the lower end of a part of the vertical Förderka channel ( 15 ) of the absorbent in the middle of the desulfurization reactor, at which end the absorbent which has bound sulfur, a plug-like layer forms a substantially horizontal, in the Regene rierreaktor ( 13 ) conductive part of the delivery channel ( 16 ), with which part a gas pipe ( 19 ) for guiding the absorbent by means of the horizontal channel part ( 16 ) given gas pulses from the plug-like Layer in the regeneration reactor ( 13 ) is connected to the lower end of part of the vertical return channel ( 15 ') of the absorbent in the middle of the regeneration reactor ( 13 ), at which end the absorbent which has bound sulfur, a second plug-like layer forms a substantially horizontal part of the channel ( 17 ) which leads into the fluidized bed chamber ( 2 ) and with which a second G aszuführungsrohr ( 18 ) for guiding the absorbent by means of gas pulses from the second plug-like layer in the fluidized bed chamber ( 2 ) is connected.