CA1248737A - Device for the purification of gas, especially combustion gas - Google Patents
Device for the purification of gas, especially combustion gasInfo
- Publication number
- CA1248737A CA1248737A CA000490642A CA490642A CA1248737A CA 1248737 A CA1248737 A CA 1248737A CA 000490642 A CA000490642 A CA 000490642A CA 490642 A CA490642 A CA 490642A CA 1248737 A CA1248737 A CA 1248737A
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- granules
- gas
- air
- storage space
- combustion gas
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Each of a pair of heat exchangers in a combustion plant includes a storage space holding basic granules, and will alter-natingly be flowed through by combustion gas and air, respec-tively. Residual heat from the combustion gas will be absorbed by the granules, and the moisture content of the gases will con-dense upon the granules. Sulphur dioxide in the combustion gas will react with the basic material to calcium sulphite, and the moist granules will catch ash particles and other contaminants in the gas. When valves have been re-set, air is made to pass through the granules, whereby it will be preheated. The heated air may be conducted to a burner, to a regeneration apparatus for the granules, or through a conduit to the gas exhaust duct.
After some time of operation the granules are transferred to the regeneration apparatus, which includes a rotatable drum, where the granules will be subjected to mechanical working and separa-tion of calcium sulphate and dust particles, preferably while being heated.
Each of a pair of heat exchangers in a combustion plant includes a storage space holding basic granules, and will alter-natingly be flowed through by combustion gas and air, respec-tively. Residual heat from the combustion gas will be absorbed by the granules, and the moisture content of the gases will con-dense upon the granules. Sulphur dioxide in the combustion gas will react with the basic material to calcium sulphite, and the moist granules will catch ash particles and other contaminants in the gas. When valves have been re-set, air is made to pass through the granules, whereby it will be preheated. The heated air may be conducted to a burner, to a regeneration apparatus for the granules, or through a conduit to the gas exhaust duct.
After some time of operation the granules are transferred to the regeneration apparatus, which includes a rotatable drum, where the granules will be subjected to mechanical working and separa-tion of calcium sulphate and dust particles, preferably while being heated.
Description
B'~
The present Inventlon relates to a devlce for the purlflcatlon of gas, especlally combustlon gas. Combustlon gases from a furnace contaln a certaln amount of heat energy, whlch cannot be reclalmed In the combustlon plant, or In conventlonal heat exchangers. There /s a/so corros/ve matter, such as sulphur compounds, dust partlc/es and other contamlnants, whlch are dlf-flcult to remove, and whlch may cause envlronmental troub/e.
The present Inventlon prov/des a devlce, whlch permlts an effIclent utlllzatlon of the resldual heat In combustlon gases for heatlng alr, and slmultaneously makes It posslble to purlfy the latter, comprlslng neutrallzatlon of corroslve/acld compounds and collectlng gas entralned ashes, partlcle-bound heavy meta/s and certaln gaseous mercury compounds. rhe rest product wlll be a chemlcally stable compound, whlch may be eas/ly d/sposed of.
Accordlng to the present Inventlon there Is prov/ded a dev/ce for alr preheatlng and the purlflcatlon of gas, especlally combustlon gas, and Includlng a regeneratlve heat exchanger con-nected to a plant produclng contam/nated gas, sald heat exchangercomprls/ng at least two ll~e unlts for a/ternate use In purlflca-t/on of gas and preheatlng of alr, respect/ve/y, each unlt havlng a storage space holdlng heat storlng bodles, the heat exchanger belng provlded wlth sw/tch-over valves guldlng the f/ow of gas and alr so they wlll pass In opposlte dlrectlons through the storage spaces, each storage space belng provlded wlth connec-tlons at Its /ower part and further connectlons at Its upper part, and holdlng a quantlty of baslc granules, each unlt and the gas Inlet connect/on thereto belng arranged so the temperature wlthln the assoclated storage space wlll be reduced to below the dew polnt of the combustlon gases occaslonally passlng thereto, and each storage space belng provlded wlth Internal, perforated partltlon walls, dlvldlng the space Into at least two chambers, permlttlng a baslcally transverse f/ow of the gas, and alr, respectlvely, In relatlon to the granules wlthln the storage space.
I
.
'' ~z~ 3~
Thus, the devlce Includes a regeneratlve heat exchanger connected to a plant produclng contamlnated gas, sald heat exchanger comprlslng at /east two unlts for alternate use and each havlng a storage space holdlng heat storlng bodles and belng provlded wlth connectlons permlttlng the passage of combustlon gas and alr, respect/vely. The Inventlon Is character/zed In that the heat storlng bodles Include a certa/n quantlty of baslc granu/es, each unlt belng provlded wlth connect/ons at Its /ower end and further connect!ons at Its upper end, as well as swltch-over va/ves guldlng the flow through the storage spaces, so con-tamlnated gas wlll pass In one dlrectlon and alternatlvely alr wlll pass In the opposlte dlrectlon, whereln each unlt and the gas Inlet connectlon thereto are arranged so the temperature wlthln the storage space wlll be reduced to below the dew polnt for molsture In the combustlon gases.
The molsture wlll blnd fly ashes, partlcle-bound heavy ~ Z~ 3~
; 2 metals and certain gaseous mercury compounds, and will expedite the reaction between the sulphur dioxide and the basic granules.
The connections to the storage space are preferably arranged so the gas will pass the storage space from above, downwardly, whereas the air will pass from below, upwardly.
Alternatively, the connections may be arranged so the gas will pass from the interior at the storage space and out-wardly, whereas the air will pass from the exterior and inwardly. The storage space is advantageously provided with internal, perforated portion walls, dividing the space into at least two chambers, permitting a basically transverse flow of the gas, and air, respectively.
The heat exchanger is preferably combined with an appa-ratus for cleaning the basic granules, as well as means for transporting the granules from the storage space to the appratus and back to the storage space, and for removing spent material therefrom. The cleaning apparatus preferably includes a rotating, heated drum. This may be provided with a connection for receiving part of the heated air, so the chemical reaction continues. Hereby calcium sulphite bound to the granules will be further oxidized into calcium sul-phate. This is a stable and inert rest product, which may be deposed without noticeable inconvenience. The chemically spent surface layer of the granules will be ground off while the drum is rotated, so fresh material is available, when the granules are transferred back to the heat exchanger for re-use.
Part of the heated air may be transferred to the burner of a furnace, where the contaminated gas is prod~ced.
During certain operating conditions an exces~ of heated air is produced in the heat exchanger. This may advan-tageously be transferred to the gas exhaust duct in order to increase the rising properties of the gases.
The heat exchanger is advantageously provided with means to measure the content of sulphur dioxide in the com-bustion gas ef~luent, and for govering the transfer of ~ranules from and to the storage space to maintain a ' . ' .
~Z'~ 7 predetermined value of reaction intense basic contact surface.
The invention will below be described with reference -to the accompanying drawings, in which Figure l shows a cross section through a heat exchanger according to the invention connected to a furnace, and a regeneration apparatus, which are schemati-cally denoted, and Figures 2 - 4 schematically shows different arrangements of the storage ~pace and the passages therein.
In Figure 1 reference 10 denotes a furnace ~orming part of a boiler provided with a burner 11 for gaseous, liquid or solid fuel, which is supplied with heated air from a combustion gas purifier/heat exchanger through a conduit 12. The combustion gas conduit directly connected to the boiler/furnace is denoted by 13.
In order to reclaim residual heat in the combustion gases, and to render undesirable emissions therein harm-less there are heat exchangers/filters l~. These will alternatively be passed through by combustion gases, which give off part of their residual heat, and by air, which will be heated. The plant therefore includes at least two similar units, even if one only is shown in the drawing.
Preferably a third unit is held as a reserve, which makes it possi~le to cut out each unit in turn for cleaning and overhaul.
The shape of the heat exchanger units may vary, and the size will of course depend upon the capacity of the combus-tion plant. A pre~rred embodiment comprises a tower-like structure, where the base measures are less than the height, and which encloses a storage space 15 containing basic granules 16. This advantageousl~ contains crushed limestone, or similar matter, but may possibly consist of macadam or some other carrier, provided with a basic surface coating.
In the embodiment shown, the storage space is provided with a bo~tom 17, which from a central, longitudinally run-ning slot 18 is inclined downwardly to both sides, towards '3~7 exits 19. These may be closed by lids 20, and adjacent to the slot 18 there is a flap valve 21.
The stora~e space 15 is provided with internal, as well as external partition walls 22 and 23, respectively. The internal partition walls 22 are mounted above the slot 18, and from a wedge-shaped void above the latter. The external partition ~alls 23 are parallel to the internal w~lls, whereby wedge-shaped voids remain between the external walls and the side walls of the unit.
The ridge-shaped roof of the unit is provided with con-nections for the air conduit 12 to the burner and the com-bustion gas conduit 13, respectively, and within the roof there is a second flap valve 24. The final gas effluent is denoted by 25, and issues from the a space below the bottom 17.
The intention is that the storage space shall alterna-tively be passed by combustion gas and air, respectively, and with two units in operation in a plant one will be supplied with gases for heating the granules, while the other unit is supplied with air which is heated by pre-viously heated granules. After some time of operation the flows of fluids are reversed.
In the operating position shown in the drawing the heat exchanger 14 is passed by air, utilizing the heat absorbed by the granules in a previGus stage.
Air enters through an opening 26 to one side of the space below the bottom 17, which is located opposite to the connection for the combustion gas conduit 25. The flap valve 21 is swung (to the right in the drawing~ so a con-nection is obtained from the opening 26, by way of slot 18, to the space between the internal partition walls 22.
Due to the design of the partition walls the air - and later the combustion gas - will pass substantially horizon-tally through the layers o~ granules, which have about uni-form thickness.
The upper flap valve 24 is turned so i~ closes t~le connection to the combustion gas conduit 13, but maintains the-connection with the air conduit open. When the flap .
s valves 24 and 21 are turne~ to their alternative positions connections for combustion gases in, and out, respectively are opened, while the air passage is cut of~.
~ here is always some moisture in the combustion gases, and in conventional plants the gas exit temperature is maintained so high, that no risk for condensation upon the heating surfaces of the boiler occurs. This means that there is rather much residual heat in the effluent.
The storage space 15 and the connection ~o the combus-tion gas e~it is according to the invention arranged so condensation of steam occurs within the storage space. The precipitated moisture greatly enhances the reaction between the sulphur dioxide content in the combustion gases and the basic granules into calcium sulphite. The moist and sticky granules prevalent in a large portion of the storage space has a high capaclty for catching fly ash, as well as particle-bound heavy metals and certain gaseous mercury compounds.
Beside the air preheating a good purification of the gases will be obtained. When air later on passes through the granules and is heated the calcium sulphite, initally formed, will at least partly be fur~her oxidized towards the more stable, final product calcium sulphate.
After some time of use ~he surface layer of the granu-les will be less reaction active. The mass of granules is made to slowly pass downwards in the unit, 50 spent material is removed at its bottom, while new, reaction-inclined material is supplied at the top.
~ n the drawing reference 27 denotes a rotatable drum enclosed in a casing (not shownl, to which the granules are supplied by some suitable transport means 28. Transfer o~
granules from the opposite side of the unit will occur hy some similar means - the transpor~ part is indicated by the broken line 29.
A regeneration and a mechanical cleaning of the granules occurs in the drum 27. The surface layers of ~he granules are worn off and separated, ~or instance by the drum being perforated, wholly or in part. ~ereby powdery , , -- ~ ... . . . .
stuff and smaller pieces from the granules will be removed while the cleaned granules are fed out of the drum by suitable means (not shown).
The cleaning apparatus is preferably common to the two heat exchanger units and contains an excess of granules, which is being treated while both storage spaces remain filled.
Transfer back to the storage spaces occurs by means of some suitable device 30, for instance a bucket or screw conveyor. A device 31 connected to the combustion gas effluent senses the content of sulphur dioxide in ~he combustion gases leaving the plant, and will govern the circulation of granules so the sulphur dioxide content does not exceed a predetermined value.
The heat content o the combustion gases is usually higher than what it is possible to utilize for heating the air to the burner. The surplus of air can be transferred to the drum 27 by way of conduit 32. The hot air promo-tes the oxidation of the calcium sulphite on the granules into calcium sulphate, which is a stable rest product, which can easily be separated from the granules by mechanical wear, or washing. The air leaving the drum may carry a certain amount of dust and is preferably transerred to the combus-tion gas conduit 13 or directly to the units 14, so the contaminated air must pass the granule store, where the dust will be collected.
On these occasions when the excess of air is not needed in the cleaning apparatus 27 part o the air may be trans-ferred to the combustion gas effluent 25 by way of a con-duit 33 terminating in a nozzle 34, in order to lncrease the rising properties of the combustion gases.
Figures 2 - 4 schematically show some alternative embodiments of granule stores, and the combustion gas and air conduits connected thereto. In all figures the air paths are shown in full lines, while the paths of combus-tion gases are shown in broken lines.
The embodiment according to Figure 2 largely corre-sponds to that of Figure 1, but the storage space 15a has a ~2~37 form more li~e an inverted V. The partition walls 22a, 23a are inclined about corresponding to, or slightly exceeding the natural angle of repose of the granules.
Elere comparatively small surfaces on the cold side are exposed towards -the possibly still corrosive gases~
Figure 3 shows a modification where the walls 22b, 23b defining the storage space has the form o~ a regular V.
Here the surfaces at the cold side will be correspondingly bigger than in the previous example, but on the other hand there are small surfaces only at the warm side, which must be insulated to prevent condensation.
As is evident from Figure 4, the partition walls 22c, 23c can be located vertically. In this manner two parallel part storage shafts 15c are obtained, which may be comple-tely separated, or may be interconnected by supply and feeding-out means for the granules. The combustion gases will pass from within and outwardly, while air passes from without and inwardly.
The embodiments above described and shown in the drawings are to be regarded as examples only, and the com-ponents thereof may be varied in many ways within the scope of the appended claims. The storage space may be formed as a single shaft - located between two partition walls, and the bottom 17 can be formed so its sides slope towards the centre. These will ensure a simpler feeding-out of the granules.
Instead of the rotating drum 27, a shaking screen or some similar device may be used, where the granules will be subjected to mechanical wear and the influence of air, while simultaneously smaller particles are removed.
The invention is described as used in connection with a furnace, but it is evident that it may also be used in con-nection with industrial processes, where hot, contaminated gas is produced.
The present Inventlon relates to a devlce for the purlflcatlon of gas, especlally combustlon gas. Combustlon gases from a furnace contaln a certaln amount of heat energy, whlch cannot be reclalmed In the combustlon plant, or In conventlonal heat exchangers. There /s a/so corros/ve matter, such as sulphur compounds, dust partlc/es and other contamlnants, whlch are dlf-flcult to remove, and whlch may cause envlronmental troub/e.
The present Inventlon prov/des a devlce, whlch permlts an effIclent utlllzatlon of the resldual heat In combustlon gases for heatlng alr, and slmultaneously makes It posslble to purlfy the latter, comprlslng neutrallzatlon of corroslve/acld compounds and collectlng gas entralned ashes, partlcle-bound heavy meta/s and certaln gaseous mercury compounds. rhe rest product wlll be a chemlcally stable compound, whlch may be eas/ly d/sposed of.
Accordlng to the present Inventlon there Is prov/ded a dev/ce for alr preheatlng and the purlflcatlon of gas, especlally combustlon gas, and Includlng a regeneratlve heat exchanger con-nected to a plant produclng contam/nated gas, sald heat exchangercomprls/ng at least two ll~e unlts for a/ternate use In purlflca-t/on of gas and preheatlng of alr, respect/ve/y, each unlt havlng a storage space holdlng heat storlng bodles, the heat exchanger belng provlded wlth sw/tch-over valves guldlng the f/ow of gas and alr so they wlll pass In opposlte dlrectlons through the storage spaces, each storage space belng provlded wlth connec-tlons at Its /ower part and further connectlons at Its upper part, and holdlng a quantlty of baslc granules, each unlt and the gas Inlet connect/on thereto belng arranged so the temperature wlthln the assoclated storage space wlll be reduced to below the dew polnt of the combustlon gases occaslonally passlng thereto, and each storage space belng provlded wlth Internal, perforated partltlon walls, dlvldlng the space Into at least two chambers, permlttlng a baslcally transverse f/ow of the gas, and alr, respectlvely, In relatlon to the granules wlthln the storage space.
I
.
'' ~z~ 3~
Thus, the devlce Includes a regeneratlve heat exchanger connected to a plant produclng contamlnated gas, sald heat exchanger comprlslng at /east two unlts for alternate use and each havlng a storage space holdlng heat storlng bodles and belng provlded wlth connectlons permlttlng the passage of combustlon gas and alr, respect/vely. The Inventlon Is character/zed In that the heat storlng bodles Include a certa/n quantlty of baslc granu/es, each unlt belng provlded wlth connect/ons at Its /ower end and further connect!ons at Its upper end, as well as swltch-over va/ves guldlng the flow through the storage spaces, so con-tamlnated gas wlll pass In one dlrectlon and alternatlvely alr wlll pass In the opposlte dlrectlon, whereln each unlt and the gas Inlet connectlon thereto are arranged so the temperature wlthln the storage space wlll be reduced to below the dew polnt for molsture In the combustlon gases.
The molsture wlll blnd fly ashes, partlcle-bound heavy ~ Z~ 3~
; 2 metals and certain gaseous mercury compounds, and will expedite the reaction between the sulphur dioxide and the basic granules.
The connections to the storage space are preferably arranged so the gas will pass the storage space from above, downwardly, whereas the air will pass from below, upwardly.
Alternatively, the connections may be arranged so the gas will pass from the interior at the storage space and out-wardly, whereas the air will pass from the exterior and inwardly. The storage space is advantageously provided with internal, perforated portion walls, dividing the space into at least two chambers, permitting a basically transverse flow of the gas, and air, respectively.
The heat exchanger is preferably combined with an appa-ratus for cleaning the basic granules, as well as means for transporting the granules from the storage space to the appratus and back to the storage space, and for removing spent material therefrom. The cleaning apparatus preferably includes a rotating, heated drum. This may be provided with a connection for receiving part of the heated air, so the chemical reaction continues. Hereby calcium sulphite bound to the granules will be further oxidized into calcium sul-phate. This is a stable and inert rest product, which may be deposed without noticeable inconvenience. The chemically spent surface layer of the granules will be ground off while the drum is rotated, so fresh material is available, when the granules are transferred back to the heat exchanger for re-use.
Part of the heated air may be transferred to the burner of a furnace, where the contaminated gas is prod~ced.
During certain operating conditions an exces~ of heated air is produced in the heat exchanger. This may advan-tageously be transferred to the gas exhaust duct in order to increase the rising properties of the gases.
The heat exchanger is advantageously provided with means to measure the content of sulphur dioxide in the com-bustion gas ef~luent, and for govering the transfer of ~ranules from and to the storage space to maintain a ' . ' .
~Z'~ 7 predetermined value of reaction intense basic contact surface.
The invention will below be described with reference -to the accompanying drawings, in which Figure l shows a cross section through a heat exchanger according to the invention connected to a furnace, and a regeneration apparatus, which are schemati-cally denoted, and Figures 2 - 4 schematically shows different arrangements of the storage ~pace and the passages therein.
In Figure 1 reference 10 denotes a furnace ~orming part of a boiler provided with a burner 11 for gaseous, liquid or solid fuel, which is supplied with heated air from a combustion gas purifier/heat exchanger through a conduit 12. The combustion gas conduit directly connected to the boiler/furnace is denoted by 13.
In order to reclaim residual heat in the combustion gases, and to render undesirable emissions therein harm-less there are heat exchangers/filters l~. These will alternatively be passed through by combustion gases, which give off part of their residual heat, and by air, which will be heated. The plant therefore includes at least two similar units, even if one only is shown in the drawing.
Preferably a third unit is held as a reserve, which makes it possi~le to cut out each unit in turn for cleaning and overhaul.
The shape of the heat exchanger units may vary, and the size will of course depend upon the capacity of the combus-tion plant. A pre~rred embodiment comprises a tower-like structure, where the base measures are less than the height, and which encloses a storage space 15 containing basic granules 16. This advantageousl~ contains crushed limestone, or similar matter, but may possibly consist of macadam or some other carrier, provided with a basic surface coating.
In the embodiment shown, the storage space is provided with a bo~tom 17, which from a central, longitudinally run-ning slot 18 is inclined downwardly to both sides, towards '3~7 exits 19. These may be closed by lids 20, and adjacent to the slot 18 there is a flap valve 21.
The stora~e space 15 is provided with internal, as well as external partition walls 22 and 23, respectively. The internal partition walls 22 are mounted above the slot 18, and from a wedge-shaped void above the latter. The external partition ~alls 23 are parallel to the internal w~lls, whereby wedge-shaped voids remain between the external walls and the side walls of the unit.
The ridge-shaped roof of the unit is provided with con-nections for the air conduit 12 to the burner and the com-bustion gas conduit 13, respectively, and within the roof there is a second flap valve 24. The final gas effluent is denoted by 25, and issues from the a space below the bottom 17.
The intention is that the storage space shall alterna-tively be passed by combustion gas and air, respectively, and with two units in operation in a plant one will be supplied with gases for heating the granules, while the other unit is supplied with air which is heated by pre-viously heated granules. After some time of operation the flows of fluids are reversed.
In the operating position shown in the drawing the heat exchanger 14 is passed by air, utilizing the heat absorbed by the granules in a previGus stage.
Air enters through an opening 26 to one side of the space below the bottom 17, which is located opposite to the connection for the combustion gas conduit 25. The flap valve 21 is swung (to the right in the drawing~ so a con-nection is obtained from the opening 26, by way of slot 18, to the space between the internal partition walls 22.
Due to the design of the partition walls the air - and later the combustion gas - will pass substantially horizon-tally through the layers o~ granules, which have about uni-form thickness.
The upper flap valve 24 is turned so i~ closes t~le connection to the combustion gas conduit 13, but maintains the-connection with the air conduit open. When the flap .
s valves 24 and 21 are turne~ to their alternative positions connections for combustion gases in, and out, respectively are opened, while the air passage is cut of~.
~ here is always some moisture in the combustion gases, and in conventional plants the gas exit temperature is maintained so high, that no risk for condensation upon the heating surfaces of the boiler occurs. This means that there is rather much residual heat in the effluent.
The storage space 15 and the connection ~o the combus-tion gas e~it is according to the invention arranged so condensation of steam occurs within the storage space. The precipitated moisture greatly enhances the reaction between the sulphur dioxide content in the combustion gases and the basic granules into calcium sulphite. The moist and sticky granules prevalent in a large portion of the storage space has a high capaclty for catching fly ash, as well as particle-bound heavy metals and certain gaseous mercury compounds.
Beside the air preheating a good purification of the gases will be obtained. When air later on passes through the granules and is heated the calcium sulphite, initally formed, will at least partly be fur~her oxidized towards the more stable, final product calcium sulphate.
After some time of use ~he surface layer of the granu-les will be less reaction active. The mass of granules is made to slowly pass downwards in the unit, 50 spent material is removed at its bottom, while new, reaction-inclined material is supplied at the top.
~ n the drawing reference 27 denotes a rotatable drum enclosed in a casing (not shownl, to which the granules are supplied by some suitable transport means 28. Transfer o~
granules from the opposite side of the unit will occur hy some similar means - the transpor~ part is indicated by the broken line 29.
A regeneration and a mechanical cleaning of the granules occurs in the drum 27. The surface layers of ~he granules are worn off and separated, ~or instance by the drum being perforated, wholly or in part. ~ereby powdery , , -- ~ ... . . . .
stuff and smaller pieces from the granules will be removed while the cleaned granules are fed out of the drum by suitable means (not shown).
The cleaning apparatus is preferably common to the two heat exchanger units and contains an excess of granules, which is being treated while both storage spaces remain filled.
Transfer back to the storage spaces occurs by means of some suitable device 30, for instance a bucket or screw conveyor. A device 31 connected to the combustion gas effluent senses the content of sulphur dioxide in ~he combustion gases leaving the plant, and will govern the circulation of granules so the sulphur dioxide content does not exceed a predetermined value.
The heat content o the combustion gases is usually higher than what it is possible to utilize for heating the air to the burner. The surplus of air can be transferred to the drum 27 by way of conduit 32. The hot air promo-tes the oxidation of the calcium sulphite on the granules into calcium sulphate, which is a stable rest product, which can easily be separated from the granules by mechanical wear, or washing. The air leaving the drum may carry a certain amount of dust and is preferably transerred to the combus-tion gas conduit 13 or directly to the units 14, so the contaminated air must pass the granule store, where the dust will be collected.
On these occasions when the excess of air is not needed in the cleaning apparatus 27 part o the air may be trans-ferred to the combustion gas effluent 25 by way of a con-duit 33 terminating in a nozzle 34, in order to lncrease the rising properties of the combustion gases.
Figures 2 - 4 schematically show some alternative embodiments of granule stores, and the combustion gas and air conduits connected thereto. In all figures the air paths are shown in full lines, while the paths of combus-tion gases are shown in broken lines.
The embodiment according to Figure 2 largely corre-sponds to that of Figure 1, but the storage space 15a has a ~2~37 form more li~e an inverted V. The partition walls 22a, 23a are inclined about corresponding to, or slightly exceeding the natural angle of repose of the granules.
Elere comparatively small surfaces on the cold side are exposed towards -the possibly still corrosive gases~
Figure 3 shows a modification where the walls 22b, 23b defining the storage space has the form o~ a regular V.
Here the surfaces at the cold side will be correspondingly bigger than in the previous example, but on the other hand there are small surfaces only at the warm side, which must be insulated to prevent condensation.
As is evident from Figure 4, the partition walls 22c, 23c can be located vertically. In this manner two parallel part storage shafts 15c are obtained, which may be comple-tely separated, or may be interconnected by supply and feeding-out means for the granules. The combustion gases will pass from within and outwardly, while air passes from without and inwardly.
The embodiments above described and shown in the drawings are to be regarded as examples only, and the com-ponents thereof may be varied in many ways within the scope of the appended claims. The storage space may be formed as a single shaft - located between two partition walls, and the bottom 17 can be formed so its sides slope towards the centre. These will ensure a simpler feeding-out of the granules.
Instead of the rotating drum 27, a shaking screen or some similar device may be used, where the granules will be subjected to mechanical wear and the influence of air, while simultaneously smaller particles are removed.
The invention is described as used in connection with a furnace, but it is evident that it may also be used in con-nection with industrial processes, where hot, contaminated gas is produced.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A device for air preheating and the purification of gas, especially combustion gas, and including a regenerative heat exchanger connected to a plant producing contaminated gas, said heat exchanger comprising at least two like units for alternate use in purification of gas and preheating of air, respectively, each unit having a storage space holding heat storing bodies, the heat exchanger being provided with switch-over valves guiding the flow of gas and air so they will pass in opposite directions through the storage spaces, each storage space being provided with connections at its lower part and further connections at its upper part, and holding a quantity of basic granules each unit and the gas inlet connection thereto being arranged so the temperature within the associated storage space will be reduced to below the dew point of the combustion gases occasionally passing thereto, and each storage space being provided with internal, perforated partition walls, dividing the space into at least two chambers, permitting a basically transverse flow of the gas, and air, respectively, in relation to the granules within the storage space.
2. A device according to claim 1 in which an apparatus for cleaning the granules and means for transporting granules from the storage spaces to the apparatus and back to the storage spaces.
3. A device according to claim 2 in which the cleaning apparatus includes a rotatable, heated drum.
4. A device according to claim 2 or 3 in which the cleaning apparatus is provided with a connection for receiving part of the heated air.
5. A device according to claim 1, 2 or 3 in which the combustion gas effluent, and for governing the transfer of granules from and to the storage spaces, to maintain a predeter-mined value of reaction intense basic contact surface at the granules.
6. A device according to claim 1, 2 or 3 having a con-duit for transferring an optional quantity of heated air to the combustion gas exhaust duct.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000490642A CA1248737A (en) | 1985-09-13 | 1985-09-13 | Device for the purification of gas, especially combustion gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000490642A CA1248737A (en) | 1985-09-13 | 1985-09-13 | Device for the purification of gas, especially combustion gas |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1248737A true CA1248737A (en) | 1989-01-17 |
Family
ID=4131379
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000490642A Expired CA1248737A (en) | 1985-09-13 | 1985-09-13 | Device for the purification of gas, especially combustion gas |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1248737A (en) |
-
1985
- 1985-09-13 CA CA000490642A patent/CA1248737A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |