CN112973443B - Fin type SCR catalyst attachment framework structure and flue gas denitration system and method - Google Patents
Fin type SCR catalyst attachment framework structure and flue gas denitration system and method Download PDFInfo
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Abstract
The invention provides a finned SCR catalyst adhesion framework structure, a flue gas denitration system and a flue gas denitration method, and belongs to the technical field of low-temperature SCR denitration, wherein the framework structure comprises the following components: each side wall of the outer box body is provided with a plurality of trapezoidal grooves formed by outwards extruding; the inner box body is arranged in the outer box body, and each side wall of the inner box body is provided with a plurality of slots with one ends opened; one end of each fin framework is inserted into the corresponding trapezoidal groove, the other end of each fin framework is inserted into the corresponding slot, and the end parts of every 2 fin frameworks are fixedly connected through pins; two side walls of each fin framework are coated with SCR catalysts; one of inner box is served and is provided with a plurality of baffles for fixed a plurality of fin skeletons. The system and the method not only can utilize the fused salt solar light-gathering and heat-storage system to heat the air at normal temperature to overcome the inactivation or poisoning of the SCR catalyst, but also can improve the flow velocity of the flue gas in the flue by improving the flow velocity of the high-temperature air.
Description
Technical Field
The invention relates to the technical field of low-temperature SCR denitration, in particular to a finned SCR catalyst adhesion framework structure, a flue gas denitration system and a flue gas denitration method.
Background
Selective catalytic reduction (SCR for short) is a mainstream technology widely applied to flue gas denitration in thermal power plants at home and abroad, and has mature technical experience and high denitration efficiency, but as the load of power plant operation at the present stage is reduced, the flue gas temperature is reduced, the tail flue gas temperature of non-electric industries such as steel, glass, cement, coking plants and the like is also lower, and the industrial application of the low-temperature SCR technology becomes the current bottleneck problem.
At present, the main technical difficulties of the low-temperature SCR denitration technology are as follows: first, the most widespread commercial V 2 O 5 -WO 3 (MoO 3 )/TiO 2 The catalyst has an active temperature of 300-400 ℃, the temperature of the existing sintering flue gas, coke oven flue gas or power plant flue gas after desulfurization and dust removal in China is usually 120-200 ℃, when the catalyst is directly used for denitration under the condition that the flue gas temperature is lower than 200 ℃, the denitration efficiency is low, and NH in the flue gas after denitration is performed 3 The escape amount is large, and the existing strict emission standard cannot be met; second, SO in the flue gas at low temperature 2 Resulting in sulfur poisoning of the catalyst and the production of ammonium sulfate salts on the surface of the catalyst.
Aiming at the technical difficulties faced by the denitration catalyst at low temperature, two solutions are provided: firstly, the flue gas temperature at the inlet of the SCR denitration system is improved by adopting a bypass temperature raising mode; and secondly, a novel denitration catalyst formula is developed to ensure that the denitration catalyst has high flue gas denitration efficiency at a lower flue gas temperature. Wherein, adopt the bypass to carry the warm mode to exist and carry the warm effect and be less than heating power calculated value and the uneven phenomenon of gas temperature, the structural feature of original flue, the flue structure of bypass and arrange the position and all can produce great influence to carrying the warm effect, the flue gas that relies on the inside heat transfer of unit is carried warm restriction to the mode that the bypass was carried warm simultaneously can't be broken through. And the amount of engineering for reforming the flue in a bypass temperature raising mode is large, and the engineering cost is large. Most research on the development of novel SCR denitration catalysts has focused on transition metal oxide catalysts. Except for V 2 O 5 -WO 3 (MoO 3 )/TiO 2 In addition, the denitration catalyst such as Mn-based, fe-based, ce-based and other metal oxides is superior to the commercial vanadium tungsten titanium catalyst at low temperatureLow temperature denitration activity of the agent. However, the low-temperature catalysts reported at present, such as Mn-based, fe-based, ce-based and the like, have poor water-resistant and sulfur-resistant performances, and the medium-high sulfur coal in the coal resources of China accounts for about 30%, so that the low-temperature catalysts researched at present are difficult to realize industrial application.
In addition, the tail flue gas of the coal-fired or oil-fired boiler often contains sulfur trioxide (SO) 3 ) And sulfur dioxide (SO) 2 ) Sulfur trioxide (SO) in flue gases 3 ) Usually accounting for total Sulfur Oxides (SO) x ) 2-5% of the content, the SCR catalyst can also partially oxidize sulfur dioxide (SO) 2 ) Conversion to sulfur trioxide (SO) 3 ) Sulfur trioxide (SO) 3 ) Is easy to react with ammonia (NH) 3 ) Reaction to produce ammonium bisulfate ((NH) 4 )HSO 4 ). After the fly ash particles are captured by the liquid ammonium bisulfate, the fly ash particles are deposited and adhered to the surface of the catalyst under the action of gravity, so that the blockage of physical channels of the catalyst and the coverage of active sites of the catalyst are caused, and finally the catalyst is poisoned and inactivated.
In order to reduce the poisoning effect of ammonium bisulfate on the vanadium tungsten titanium catalyst, the density of an SCR catalyst reaction unit is generally reduced or the content of vanadium in the vanadium tungsten titanium catalyst is reduced to below 1 percent. In addition, when the temperature of the tail flue gas is higher: (>290 ℃), the ammonium bisulfate poisoning phenomenon of the catalyst is also reduced, but the flue gas temperature of a thermal power plant operating at low load or non-electric power industries such as steel, glass and the like does not meet the operation requirement, and SO is generated at low temperature 2 Is very easy to react with NH 3 Combined with subsequent further oxidation to form ammonium bisulfate ((NH) 4 )HSO 4 )。
Currently, research focuses on formulation development, reaction mechanism, catalyst poisoning and regeneration of catalysts and the like in scientific research institutes and universities in China, research on forming, preparation processes and the like of monolithic catalysts is less, production and preparation are mainly carried out by means of foreign technologies, and the cost of monolithic catalysts is high, so that a novel SCR denitration catalyst framework mechanism, a denitration system and a denitration method are needed to be developed for solving the problems of activity failure and low-temperature poisoning of SCR catalysts in the low-temperature flue gas denitration process and overcoming the defect that ash is easy to accumulate in low flow rate of flue gas (less than 3 m/s).
Disclosure of Invention
In order to solve the above problems, the present invention provides a fin-type SCR catalyst attachment framework structure, which can not only provide a specific surface area equivalent to that of a flat-plate or corrugated-plate SCR catalyst, but also form a high-efficiency heat exchange channel, so that heat of high-temperature air can be rapidly and uniformly transferred to the catalyst; and the framework is convenient to assemble and high in repeated utilization rate.
In order to achieve the above object, the technical scheme of the invention is as follows.
A finned SCR catalyst attachment framework structure comprising:
the outer box body is in a channel shape, and each side wall of the outer box body is provided with a plurality of trapezoidal grooves formed by extruding outwards;
the inner box body is in a channel shape and is arranged in the outer box body, and each side wall of the inner box body is provided with a plurality of slots with one open end;
the fin frameworks are L-shaped, one ends of the fin frameworks are inserted into the corresponding trapezoidal grooves, the other ends of the fin frameworks are inserted into the corresponding slots, and the end parts of every 2 fin frameworks in the inner box body are fixedly connected through pins; two side walls of each fin framework between the outer box body and the inner box body are coated with SCR catalysts;
a plurality of baffles are arranged at one end, close to the opening of the slot, of the inner box body and used for fixing the fin frameworks.
Furthermore, each side wall of the outer box body is provided with a trapezoidal convex beam formed by inward extrusion, and one side of each trapezoidal convex beam is abutted against the corresponding fin framework.
Further, the raw material of the SCR catalyst is V 2 O 5 -WO 3 /TiO 2 Catalyst, V 2 O 5 -MoO 3 /TiO 2 Catalyst, V 2 O 5 -WO 3 -MoO 3 /TiO 2 Any one of the catalysts.
Further, the gaps between the SCR catalysts coated on the adjacent 2 fin frameworks are 5mm.
Furthermore, every fin skeleton's one end all is provided with the dop, and the other end all is provided with fin cotter pin hole, every the equal joint of dop is in the trapezoidal recess that corresponds, every two fin cotter pin hole all is through pin fixed connection.
The invention also provides a flue gas denitration system based on the fin type SCR catalyst attaching framework structure, the flue gas denitration system can utilize a fused salt solar energy light condensation-heat storage system to heat normal temperature air, and utilize the heated high temperature air to improve the temperature of low temperature flue gas, so that the SCR catalyst is always in an active temperature range, and meanwhile, the high temperature air can also be used for reactivating the poisoned SCR catalyst (pore channels are blocked by ammonium bisulfate or active sites are covered).
A flue gas denitration system based on a finned SCR catalyst adheres to a skeleton texture includes: the system comprises a solar heat collection system, a circulating system and an air inlet system;
the circulation system includes: the system comprises a low-temperature molten salt storage tank, a high-temperature molten salt storage tank and a first heat exchanger;
the low-temperature molten salt storage tank stores low-temperature molten salt, the low-temperature molten salt flows through the solar heat collecting system under the action of a first circulating pump and is heated, and the heated molten salt is stored in the high-temperature molten salt storage tank through a first valve;
the high-temperature molten salt in the high-temperature molten salt storage tank flows into the first heat exchanger under the action of a second circulating pump, and meanwhile, cold air provided by the air inlet system enters the first heat exchanger through a first air inlet pipeline and exchanges heat with the high-temperature molten salt; the heat-exchanged molten salt flows into a low-temperature molten salt storage tank through a third circulating pump; and the heated high-temperature air flows into a heat exchange channel formed by the inner box body through a second air inlet pipeline, heats the fin frameworks and transfers the heated high-temperature air to the SCR catalyst.
Furthermore, a regulating proportional valve is arranged on the second air inlet pipeline, and cold air provided by the air inlet system is communicated with the regulating proportional valve through a third air inlet pipeline and is used for regulating the temperature of high-temperature air entering the heat exchange channel.
Furthermore, the airflow direction of the high-temperature air entering the heat exchange channel is opposite to the flowing direction of the flue gas, and the high-temperature air is used for increasing the temperature of the multiple fin frameworks, so that the temperature fields of the fin frameworks are all located within the active temperature range of the SCR catalyst.
Further, the solar energy collection system comprises: the solar heat collector comprises a solar heat collector and a second heat exchanger, wherein heat-conducting liquid is stored in the solar heat collector, the heat-conducting liquid flows into the second heat exchanger after being heated by the solar heat collector, and the heat-conducting liquid after heat exchange flows back into the solar heat collector;
the low-temperature molten salt stored in the low-temperature molten salt storage tank enters the second heat exchanger under the action of the first circulating pump, and the heated molten salt is stored in the high-temperature molten salt storage tank through the first valve.
The invention also provides a flue gas denitration method based on the flue gas denitration system, which not only can utilize the molten salt solar energy condensation-heat storage system to heat normal temperature air to overcome the inactivation or poisoning of the SCR catalyst, but also can improve the flow rate of flue gas in a flue by improving the flow rate of high temperature air, and can overcome the problem of dust deposition caused by too low flow rate of flue gas (less than 3 m/s).
A flue gas denitration method based on a flue gas denitration system comprises the following steps:
s1, mounting the assembled fin type SCR catalyst attaching framework structure in a flue;
s2, starting a solar heat collection system and a first circulating pump, introducing low-temperature molten salt in the low-temperature molten salt storage tank into the solar heat collection system, and storing the heated high-temperature molten salt in the high-temperature molten salt storage tank;
s3, starting a second circulating pump, introducing the heated high-temperature molten salt into the first heat exchanger, and simultaneously starting an air inlet system to enable cold air to enter the first heat exchanger through a first air inlet pipeline to exchange heat with the high-temperature molten salt;
the heat-exchanged molten salt enters a low-temperature molten salt storage tank through a third circulating pump;
the high-temperature air after heat exchange enters the second air inlet pipeline and is mixed with cold air flowing into the third air inlet pipeline to adjust the temperature of the air flow; the mixed high-temperature air reversely flows into a heat exchange channel formed by the inner box body and is used for increasing the temperature of the fin frameworks, so that the temperature fields of the fin frameworks are all located in the active temperature range of the SCR catalyst.
The invention has the beneficial effects that:
1. the invention can uniformly and efficiently transfer heat to the catalyst by introducing external high-temperature air and through the SCR catalyst framework with a fin structure, further maintain the overall temperature of the catalyst by controlling the temperature of the high-temperature air, and stabilize the catalyst in an optimal reaction temperature window area of a catalyst load component under different incoming flow tail flue gas conditions; meanwhile, ammonium bisulfate ((NH) deposited on the surface of the catalyst can be removed by increasing the temperature of the external high temperature air 4 )HSO 4 ) The denitration catalyst can be effectively decomposed thermally, so that the denitration performance and the sulfur resistance of the catalyst in a sulfur-containing atmosphere are improved, the service time of the catalyst is prolonged, and the denitration operation cost of an enterprise is reduced. In addition, the flow velocity of the flue gas in the flue can be changed by changing the flow velocity of the outside air, so that the problem of dust deposition caused by low flow velocity of the flue gas can be avoided.
2. The invention keeps the high denitration performance of the SCR catalyst and improves the active temperature adaptation range of the catalyst under the condition of flue gas with different temperatures, improves the anti-poisoning capability of the catalyst for sulfur-containing flue gas, realizes the active temperature control adjustment of the catalyst under different flue gas temperatures, weakens the poisoning influence of sulfur dioxide on the catalyst, prolongs the service time of the catalyst and reduces the denitration operation cost of enterprises. Meanwhile, the surface temperature of the catalyst is regulated and controlled by changing the temperature of external air, so that the problems that the optimal activity temperature window of the current high-temperature catalyst and low-temperature catalyst is narrow, the activity of the high-temperature catalyst is low in a low-temperature section, and the activity of the low-temperature catalyst is low in a high-temperature section can be solved, and the wide-load denitration of the catalyst can be realized. In addition, the flow velocity of the flue gas in the flue can be changed by changing the flow velocity of the outside air, so that the problem of dust deposition caused by low flow velocity of the flue gas can be avoided.
3. In the invention, the flue gas is coated with the catalyst raw material (V) between the inner box body and the outer box body 2 O 5 -WO 3 (MoO 3 )/TiO 2 ) The stainless steel mesh fins flow in the gaps, and the catalyst carries out denitration treatment on the flue gas. The flue gas can be gradually cooled in the flowing direction or the temperature of the flue gas is already lower than the active temperature of the catalyst, and the flue gas denitration efficiency can be seriously reduced at the moment. However, the flue gas denitration system can introduce the air subjected to solar condensation heating into the heat exchange channel formed by the inner box body, the flowing direction of the hot air is opposite to the flowing direction of the flue gas, one part of the stainless steel framework is coated with the catalyst raw material to play a role in denitration, the other part of the stainless steel framework is not coated with the catalyst raw material to play a role in enhancing heat transfer, and the heat absorption fins of the inner box body can quickly transfer the heat of the hot air to the catalyst, so that the activity of the catalyst is maintained. In addition, the temperature of the hot air in the inner box body after passing through the heat absorption fins is still higher than the temperature of the flue gas, and the hot air is mixed into the incoming flue gas, so that the temperature of the flue gas can be increased, the flow velocity of the flue gas can be increased, and the effects of strengthening catalysis and reducing particle deposition are achieved.
4. All parts except the catalyst raw material in the device can be recycled, after the catalyst on the fin framework is completely consumed, the denitration catalyst framework can be disassembled, the catalyst raw material is coated again, and the denitration catalyst framework is assembled for use again, so that the cost can be reduced on the whole.
Drawings
Fig. 1 is a schematic structural diagram of an attached framework structure of a finned SCR catalyst according to an embodiment of the present invention.
Fig. 2 is a schematic structural view of a portion a in fig. 1.
Fig. 3 is a perspective view of the inner case of fig. 1.
Fig. 4 is a schematic structural diagram of a portion B in fig. 3.
Fig. 5 is a schematic cross-sectional view of the inner case of fig. 3.
FIG. 6 is a schematic structural diagram of an inner box and a baffle in an embodiment of the invention.
Fig. 7 is a schematic structural diagram of a fin framework and an SCR catalyst in an embodiment of the present invention.
Fig. 8 is a schematic structural view of a portion C in fig. 7.
Fig. 9 is a perspective view of the outer case of fig. 1.
Fig. 10 is a schematic sectional view of the outer case of fig. 9.
Fig. 11 is a schematic structural diagram of a flue gas denitration system provided in an embodiment of the present invention.
In the figure: 1. an outer case; 11. a trapezoidal groove; 12. a trapezoidal convex beam; 2. an inner box body; 21. a slot; 3. a fin framework; 31. clamping a head; 32. pin holes of the fins; 4. an SCR catalyst; 5. a pin; 6. a baffle plate; 7. a solar energy collection system; 71. a solar heat collector; 72. a second heat exchanger; 8. a circulation system; 81. a low-temperature molten salt storage tank; 82. a high-temperature molten salt storage tank; 83. a first heat exchanger; 84. a first circulation pump; 85. a first valve; 86. a second circulation pump; 87. a third circulation pump; 9. an air intake system; 91. a first air intake duct; 92. a second air intake duct; 93. a third air intake duct; 94. and adjusting the proportional valve.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.
Fig. 1 is a schematic structural diagram of an attachment framework structure of a finned SCR catalyst according to an embodiment of the present invention. The finned SCR catalyst attachment framework structure comprises: outer box, inner box 2 and a plurality of fin skeleton 3.
Referring to fig. 1 and 9 to 10, the outer case 1 is in a channel shape, and each side wall thereof is provided with a plurality of trapezoidal grooves 11 formed by extruding outwards; each side wall of the outer box body 1 is provided with a trapezoidal convex beam 12 formed by inward extrusion, and one side of each trapezoidal convex beam 12 is abutted against the corresponding fin framework 3. For example, the number of the trapezoidal grooves 11 on each side wall of the outer case 1 is 6.
In this embodiment, outer box is by being 2mm by thickness, the width is 185 x 4mm, the stainless steel sheet book that the length is 500mm is made by welding after, the whole channel shape that is the square in cross-section of outer box, but all have 6 trapezoidal recesses that outwards extrude and 1 trapezoidal protruding roof beam that inwards extrudees and form on each stainless steel solid face, trapezoidal recess minor face is 2mm, the long limit is 5mm, highly is 2mm, trapezoidal protruding roof beam minor face 5mm, the long limit is 10mm, highly is 3mm.
Referring to fig. 1 to 6, the inner case 2 is formed in a channel shape and disposed in the outer case 1, and each sidewall thereof is provided with a plurality of slots 21 having an opening at one end. For example, the number of the slots 21 on each side wall of the inner case 2 is 6.
In the embodiment, the cross section of the inner box body is square, the stainless steel plate with the thickness of 2mm, the width of 55 multiplied by 4mm and the length of 500mm is rolled and folded into a square channel shape, then the stainless steel plate is welded into a whole at the interface, the side length of the inner box body is 55 multiplied by 500mm respectively, then 6 slits with the length of 2mm multiplied by 490mm are cut on each stainless steel solid surface of the inner box body respectively, then slots with one open end and the other closed end can be formed on the wall surface of the inner box body, and slots with the opening at the positions close to the opening positions are reserved on the wall surfaces of the inner box body between the 1 st slot, the 2 nd slot, the 3 rd slot, the 4 th slot, the 5 th slot and the 6 th slot
And the baffle pin hole is used for installing the baffle 6.
Referring to fig. 1 to 2 and 7 to 8, the fin frameworks 3 are L-shaped, one end of each fin framework is inserted into the corresponding trapezoidal groove 11, the other end of each fin framework is inserted into the corresponding slot 21, and the end parts of each 2 fin frameworks 3 in the inner box body 2 are fixedly connected through the pins 5; two side walls of each fin framework 3 between the outer box body 1 and the inner box body 2 are coated with SCR catalysts 4; specifically, the raw material of the SCR catalyst 4 is V 2 O 5 -WO 3 /TiO 2 Catalyst, V 2 O 5 -MoO 3 /TiO 2 Catalyst, V 2 O 5 -WO 3 -MoO 3 /TiO 2 Any one of the catalysts. A plurality of baffles 6 are arranged at one end of the inner box body 2 close to the opening of the slot 21 and used for fixing a plurality of fin frameworks 3. Specifically, one end of each fin framework 3 is provided with a clamping head 31, the other end of each fin framework is provided with a fin pin hole 32, each clamping head 31 is clamped in the corresponding trapezoidal groove 11, and each two fin pin holes 32 are fixedly connected through a pin 5. Here, the gap between the SCR catalysts 4 coated on the adjacent 2-piece fin skeletons 3 was 5mm. For example, the fin skeletons 3 have 6 kinds of shapes, and the number of the fin skeletons 3 of each shape is 4.
In the present embodiment, the fin frame 3 is formed by extruding a stainless steel wire mesh having a thickness of 2mm into a fin frame shape as shown in fig. 1, and the fin frame has 6 shapes each having 4 pieces. Then coating the front and back surfaces of the stainless steel framework with catalyst raw materials (V) with the thickness of 1.5mm 2 O 5 -WO 3 (MoO 3 )/TiO 2 Catalyst) and reserving a 2mm chuck at the outer end of the stainless steel framework according to the assembly size, reserving a fin pin hole at the inner end of the stainless steel framework, wherein the height of the stainless steel framework is 480mm, and the length of the stainless steel framework is different according to different shapes.
The stainless steel fin frameworks with 6 different shapes are respectively arranged in the slots of any solid surface of the inner box body, as shown in figure 1, 4 solid surfaces of the inner box body are totally arranged, 6 x 4 stainless steel fin frameworks can be completely assembled on the inner box body, and the fin frameworks are fixed by pins in pairs due to pin holes reserved at the end parts of the fins.
Because interior box slot length is 490mm, and the skeleton height is 480mm, then can reserve 10 mm's baffle mounted position at interior box slot opening part, then pass through pin joint on interior box wall with the baffle that is wide for 10mm and length for 55mm, can fix the fin skeleton in the slot and can not remove along the slot direction like this. The assembled inner box body and the fin framework are integrally installed in the outer box body, and the fin framework is further fixed due to the fact that the grooves and the protruding beams are formed in the wall face of the outer box body and can be clamped with the fin framework.
The framework structure provided by the embodiment can not only provide a specific surface area equivalent to that of a flat plate type or corrugated plate type SCR catalyst, but also facilitate the formation of a high-efficiency heat exchange channel, and can quickly and uniformly transfer the heat of high-temperature air to the catalyst. In addition, the framework is convenient to assemble and high in repeated utilization rate. After the catalyst on the fin framework is completely consumed, the denitration catalyst framework can be disassembled, the catalyst raw material is coated again, and the denitration catalyst framework is assembled again for use, so that the cost can be reduced on the whole.
Fig. 11 is a schematic structural diagram of a flue gas denitration system based on the finned SCR catalyst attachment framework structure according to an embodiment of the present invention. This flue gas deNOx systems includes: a solar heat collection system 7, a circulation system 8 and an air inlet system 9; the circulation system 8 includes: a low-temperature molten salt storage tank 81, a high-temperature molten salt storage tank 82, and a first heat exchanger 83. The solar energy collection system 7 comprises: the solar heat collector 71 and the second heat exchanger 72, heat-conducting liquid is stored in the solar heat collector 71, the heat-conducting liquid flows into the second heat exchanger 72 after being heated by the solar heat collector 71, and the heat-conducting liquid after heat exchange flows back into the solar heat collector 71. Of course, a circulation pump is provided between the solar heat collector and the second heat exchanger for driving the heat-conducting liquid to flow.
The low-temperature molten salt storage tank 81 stores therein low-temperature molten salt, the low-temperature molten salt is heated by flowing through the second heat exchanger 72 of the solar heat collecting system 7 by the first circulation pump 84, and the heated molten salt is stored in the high-temperature molten salt storage tank 82 through the first valve 85.
The high-temperature molten salt in the high-temperature molten salt storage tank 82 flows into the first heat exchanger 83 under the action of the second circulating pump 86, and meanwhile, cold air provided by the air inlet system 9 enters the first heat exchanger 83 through the first air inlet pipeline 91 and exchanges heat with the high-temperature molten salt; the molten salt after heat exchange flows into the low-temperature molten salt storage tank 81 through a third circulating pump 87; the heated high-temperature air flows into the heat exchange channel formed by the inner box body 2 through the second air inlet pipeline 92, heats the plurality of fin frameworks 3, and is transferred to the SCR catalyst 4.
Of course, in this embodiment, a proportional regulating valve 94 may be further disposed on the second air inlet duct 92, and the cold air provided by the air inlet system 9 is communicated with the proportional regulating valve 94 through a third air inlet duct 93 for regulating the temperature of the high temperature air entering the heat exchange channel. The airflow direction of the high-temperature air entering the heat exchange channel is opposite to the flowing direction of the flue gas, and the high-temperature air is used for increasing the temperature of the multiple fin frameworks 3, so that the temperature fields of the fin frameworks are all located within the active temperature range of the SCR catalyst.
The main purpose of the opposite flow direction of the high-temperature air into the heat exchange channels is to better increase the temperature of the fin framework, since the flue gas temperature decreases gradually with the flow direction, which results in the flue gas temperature being lower than the SCR catalyst active temperature range. The flowing direction of the high-temperature air is opposite to the flowing direction of the flue gas, and the temperature of the high-temperature air is reduced along with the flowing direction of the flue gas, so that the fin framework part with more serious SCR catalyst deactivation is heated by the air with higher temperature, and the temperature field of the whole fin framework is promoted to be within the activity range of the SCR catalyst. In addition, the secondary purpose of the opposite flow direction is to allow for adjustment of flue gas flow rate and temperature.
In the embodiment, the flue gas denitration system heats the molten salt by means of solar light condensation to store heat, then continuously releases the heat of the molten salt to the normal temperature air, and reversely introduces the heated high temperature air into the heat exchange channel in the center of the flue, the heat of the high temperature air is uniformly transferred to the catalyst through the fin type catalyst adhesion framework, the temperature of the high temperature air can be regulated and controlled by the proportion of the mixed normal temperature air, and then the purpose of maintaining the activity temperature of the SCR catalyst is achieved, namely when the flue gas temperature is low, the mixed amount of the normal temperature air is small, and otherwise, the mixed amount is large.
In addition, when the catalyst is poisoned, i.e., the catalyst is poisoned with ammonium bisulfate ((NH) 4 )HSO 4 ) Covering, by raising the temperature of the high temperature air, ammonium bisulfate ((NH) 4 )HSO 4 ) Volatilize and further revive the catalyst.
The system can also achieve the flow velocity of the flue gas in the flue by regulating and controlling the flow velocity of the reverse high-temperature air, thereby overcoming the defect that the ash is easy to accumulate under the low flow velocity of the flue gas (less than 3 m/s).
A flue gas denitration method based on the flue gas denitration system comprises the following steps:
s1, mounting the assembled fin type SCR catalyst attaching framework structure in a flue;
s2, starting the solar heat collection system 7 and the first circulating pump 84, introducing the low-temperature molten salt in the low-temperature molten salt storage tank 81 into the solar heat collection system 7, and storing the heated high-temperature molten salt in the high-temperature molten salt storage tank 82;
s3, starting a second circulating pump 86, introducing the heated high-temperature molten salt into the first heat exchanger 83, simultaneously starting the air inlet system 9, and introducing cold air into the first heat exchanger 83 through a first air inlet pipeline 91 to exchange heat with the high-temperature molten salt;
the molten salt after heat exchange enters a low-temperature molten salt storage tank 81 through a third circulating pump 87;
the high-temperature air after heat exchange enters the second air inlet pipeline 92 and is mixed with cold air flowing into the third air inlet pipeline 93 to adjust the temperature of the air flow; the mixed high-temperature air reversely flows into a heat exchange channel formed by the inner box body 2 and is used for increasing the temperature of the fin frameworks 3, so that the temperature fields of the fin frameworks are all located in the active temperature range of the SCR catalyst.
The flue gas denitration method provided by the embodiment of the invention mainly utilizes the flue gas denitration system provided by the embodiment of the invention, and is mainly applied to flue gas denitration under the low-temperature condition. The heat is uniformly and efficiently transferred to the catalyst by introducing external high-temperature air and through the SCR catalyst framework with a fin structure, the overall temperature of the catalyst is kept stable in an optimal reaction temperature window area of a catalyst load component by controlling the temperature of the external high-temperature air, and ammonium bisulfate ((NH) deposited on the surface of the catalyst can be obtained by increasing the temperature of the external high-temperature air 4 )HSO 4 ) The catalyst is effectively decomposed thermally, so that the denitration performance and the sulfur resistance of the catalyst in a sulfur-containing atmosphere are improved. In addition, the flow speed of the outside air can be changed to change the inside of the flueThe flow velocity of the flue gas can avoid the problem of dust deposition caused by low flow velocity of the flue gas.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A finned SCR catalyst attachment framework structure is characterized by comprising:
the outer box body (1) is in a channel shape, and each side wall of the outer box body is provided with a plurality of trapezoidal grooves (11) formed by outwards extruding;
the inner box body (2) is in a channel shape and is arranged in the outer box body (1), and each side wall of the inner box body is provided with a plurality of slots (21) with one open end;
the fin frameworks (3) are L-shaped, one ends of the fin frameworks are inserted into the corresponding trapezoidal grooves (11), the other ends of the fin frameworks are inserted into the corresponding slots (21), and the end parts of every 2 fin frameworks (3) positioned in the inner box body (2) are fixedly connected through pins (5); two side walls of each fin framework (3) between the outer box body (1) and the inner box body (2) are coated with SCR catalysts (4);
the inner box body (2) is close to one end of the opening of the slot (21) and is provided with a plurality of baffles (6) for fixing a plurality of fin frameworks (3).
2. The finned SCR catalyst attaching framework structure according to claim 1, wherein each sidewall of the outer case (1) is provided with a trapezoidal protruding beam (12) formed by inward extrusion, and one side of each trapezoidal protruding beam (12) abuts against the corresponding fin framework (3).
3. The finned SCR catalyst adhesion framework structure of claim 1, wherein the SCR catalyst (4) is prepared from V 2 O 5 -WO 3 /TiO 2 Catalyst, V 2 O 5 -MoO 3 /TiO 2 Catalyst and process for preparing same、V 2 O 5 -WO 3 -MoO 3 /TiO 2 Any one of the catalysts.
4. The finned SCR catalyst attachment framework structure of claim 1, wherein the gaps between SCR catalysts (4) coated on the adjacent 2 fin frameworks (3) are 5mm.
5. The finned SCR catalyst attaching framework structure as recited in claim 1 or 4, wherein each fin framework (3) is provided with a clamp head (31) at one end and a fin pin hole (32) at the other end, each clamp head (31) is clamped in the corresponding trapezoidal groove (11), and each two fin pin holes (32) are fixedly connected through a pin (5).
6. A flue gas denitration system based on the finned SCR catalyst attaching framework structure of claim 1, characterized by comprising: the solar energy heat collecting system (7), the circulating system (8) and the air inlet system (9);
the circulation system (8) comprises: a low-temperature molten salt storage tank (81), a high-temperature molten salt storage tank (82) and a first heat exchanger (83);
the low-temperature molten salt storage tank (81) stores low-temperature molten salt, the low-temperature molten salt is heated after flowing through the solar heat collection system (7) under the action of a first circulating pump (84), and the heated molten salt is stored in the high-temperature molten salt storage tank (82) through a first valve (85);
the high-temperature molten salt in the high-temperature molten salt storage tank (82) flows into the first heat exchanger (83) under the action of a second circulating pump (86), and meanwhile, cold air provided by the air inlet system (9) enters the first heat exchanger (83) through a first air inlet pipeline (91) and exchanges heat with the high-temperature molten salt; the molten salt after heat exchange flows into a low-temperature molten salt storage tank (81) through a third circulating pump (87); the heated high-temperature air flows into a heat exchange channel formed by the inner box body (2) through a second air inlet pipeline (92), the fin frameworks (3) are heated and are transferred to the SCR catalyst (4), and the activity temperature of the SCR catalyst is 300-400 ℃.
7. The flue gas denitration system of claim 6, wherein the second air inlet pipeline (92) is provided with a regulating proportional valve (94), and cold air provided by the air inlet system (9) is communicated with the regulating proportional valve (94) through a third air inlet pipeline (93) and is used for regulating the temperature of high-temperature air entering the heat exchange channel.
8. The flue gas denitration system of claim 7, wherein the airflow direction of the high-temperature air entering the heat exchange channel is opposite to the flow direction of the flue gas, and the high-temperature air is used for increasing the temperature of the multiple fin frameworks (3) so that the temperature fields of the fin frameworks are all located within the active temperature range of the SCR catalyst.
9. The flue gas denitration system of claim 6, wherein the solar heat collection system (7) comprises: the solar heat collector (71) and the second heat exchanger (72), wherein heat-conducting liquid is stored in the solar heat collector (71), the heat-conducting liquid flows into the second heat exchanger (72) after being heated by the solar heat collector (71), and the heat-conducting liquid after heat exchange flows back into the solar heat collector (71);
the low-temperature molten salt stored in the low-temperature molten salt storage tank (81) enters the second heat exchanger (72) under the action of a first circulating pump (84), and the heated molten salt is stored in the high-temperature molten salt storage tank (82) through a first valve (85).
10. A flue gas denitration method based on the flue gas denitration system of claim 8, characterized by comprising the steps of:
s1, mounting an assembled fin type SCR catalyst attaching framework structure in a flue;
s2, starting the solar heat collection system (7) and the first circulating pump (84), introducing the low-temperature molten salt in the low-temperature molten salt storage tank (81) into the solar heat collection system (7), and storing the heated high-temperature molten salt in the high-temperature molten salt storage tank (82);
s3, starting a second circulating pump (86), introducing the heated high-temperature molten salt into the first heat exchanger (83), starting an air inlet system (9) at the same time, and allowing cold air to enter the first heat exchanger (83) through a first air inlet pipeline (91) to exchange heat with the high-temperature molten salt;
the molten salt after heat exchange enters a low-temperature molten salt storage tank (81) through a third circulating pump (87);
the high-temperature air after heat exchange enters a second air inlet pipeline (92) and is mixed with cold air flowing into a third air inlet pipeline (93) to adjust the temperature of air flow; the mixed high-temperature air reversely flows into a heat exchange channel formed by the inner box body (2) and is used for increasing the temperature of the fin frameworks (3) so that the temperature fields of the fin frameworks are all located within the active temperature range of the SCR catalyst.
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| US6203771B1 (en) * | 1992-10-28 | 2001-03-20 | Alliedsignal Inc. | Catalytic converter with metal monolith having an integral catalyst |
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| CN105276853A (en) * | 2015-09-28 | 2016-01-27 | 上海理工大学 | Multi-layer composite adsorbent bed |
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| US6203771B1 (en) * | 1992-10-28 | 2001-03-20 | Alliedsignal Inc. | Catalytic converter with metal monolith having an integral catalyst |
| CN206391871U (en) * | 2016-12-05 | 2017-08-11 | 唐山学院 | It is a kind of from dedusting type denitrating catalyst structure |
| CN207179171U (en) * | 2017-08-30 | 2018-04-03 | 湖北侨光石化装备股份有限公司 | A kind of grating type catalyst support disc |
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