CN210584405U - Dry desulfurization and denitrification device suitable for cement kiln flue gas - Google Patents
Dry desulfurization and denitrification device suitable for cement kiln flue gas Download PDFInfo
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- CN210584405U CN210584405U CN201920880776.5U CN201920880776U CN210584405U CN 210584405 U CN210584405 U CN 210584405U CN 201920880776 U CN201920880776 U CN 201920880776U CN 210584405 U CN210584405 U CN 210584405U
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Abstract
A dry desulfurization and denitrification device suitable for cement kiln flue gas comprises: the system comprises a cement kiln, a preheater, a waste heat boiler, a desulfurization absorption tower provided with a water spray gun, a dust remover and an SCR (selective catalytic reduction) medium-low temperature denitration device provided with a rectifying device and a soot blowing device which are sequentially connected; wherein, a dedusting material outlet of the deduster is communicated with a dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline; the pipeline is provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the purified gas outlet is connected with a second flue gas pipeline; the pipeline is sequentially provided with an ammonia water evaporation air outlet, a draught fan and a purified gas circulation outlet which are communicated with a feed inlet of the ammonia spraying device; the purified gas circulating outlet is respectively communicated with the flue gas circulating inlet I and the flue gas circulating inlet II. The device can high-efficiently desulfurize, remove dust and denitrate, reduce the poison of pollutants to the catalyst, reduce the system blockage and abrasion, and ensure the long-term stable operation of the whole device.
Description
Technical Field
The utility model relates to a SOx/NOx control handles technical field, and more specifically says, relates to a dry process SOx/NOx control device suitable for cement kiln flue gas.
Background
In recent years, the nation has vigorously promoted the ultra-low emission modification of flue gas in the non-electric field, the ultra-low emission modification of flue gas of a cement kiln has been proposed, and the emission concentrations of flue gas particles, sulfur dioxide and nitrogen oxides of the cement kiln are required to be respectively not higher than 10mg/m in policy documents such as local standards for a plurality of provinces and working schemes for preventing and controlling atmospheric pollution3、50mg/m3150 (or 100) mg/m3. Meanwhile, with the stricter and stricter environmental emission standards, the pollution treatment strength of the state is continuously increased, and the cement kiln smoke emission standards are revised and finished. Since 7/1/2015, the existing enterprises begin to strictly execute GB4915-2013 emission Standard for atmospheric pollutants for Cement industry, which requires NO of the existing and newly-built Cement enterprisesxEmission limit is determined byOriginal 800mg/Nm3Down to 400mg/Nm3(focal region NO)xEmission limit 320mg/Nm3). Therefore, the cement kiln flue gas is inevitably provided with a desulfurization and denitrification device.
At present, the purification routes for desulfurization and denitrification treatment of cement kiln flue gas are many, most cement enterprises adopt traditional wet desulfurization in desulfurization, but the wet desulfurization is seriously corroded, and the problems of desulfurization waste water, white elimination at the rear end and the like exist; most cement enterprises in the aspect of denitration adopt a selective non-catalytic reduction method (SNCR denitration technology), but the denitration efficiency of SNCR is about 60%, and the existing emission requirements cannot be met. With the development of the industry and the improvement of the environmental protection requirement, dry desulfurization and Selective Catalytic Reduction (SCR) denitration are adopted, which becomes the development direction for treating the flue gas of the cement kiln by technical personnel in the field.
Chinese patent application publication No. CN109364741A discloses a cement kiln flue gas dry desulfurization and high-dust SCR denitration device and process, the process flow of which is: the flue gas to be purified firstly enters an SCR device, is subjected to high-temperature SCR denitration (350 ℃), is subjected to dry desulfurization and cloth bag dust removal, and is discharged into a chimney through a draught fan. However, the above technical solutions have the following disadvantages: (1) the problems of catalyst poisoning and blockage and low denitration efficiency; because flue gas directly advances SCR device earlier among this technical scheme belongs to the high dust and arranges, and the flue gas temperature is high, and dust, CaO content are high, easily lead to catalyst poisoning deactivation and jam, and life is short, still easily causes the emergence of the operation of denitrification facility and maintenance cost high scheduling problem. (2) Downstream equipment plugging corrosion problems; because the downstream of the SCR denitration device arranged at the position is provided with facilities such as a waste heat power generation boiler, if the ammonia escape of the SCR denitration system is improperly controlled, the problems of blockage, corrosion, reduced heat efficiency and the like of the waste heat boiler are easily caused.
Chinese patent with publication number CN204619708U discloses a combined denitration device for flue gas of a rotary cement kiln, which comprises the following steps: firstly, reducing agents such as ammonia water are sprayed into the decomposing furnace 2, the flue gas needing further purification firstly enters a waste heat boiler, then is subjected to bag dust removal and finally enters an SCR device, and then is subjected to high-temperature SCR desorptionAnd (4) discharging the nitre (180-220 ℃) into a chimney through a draught fan. However, the above technical solutions have the following disadvantages: (1) the risk of catalyst poisoning and blocking, low denitration efficiency and the like exists; although the technical proposal carries out dust removal treatment, SO2And the catalyst is not effectively removed, so that the catalyst is easily poisoned, inactivated and blocked, the service life is short, and the problems of high operation and maintenance cost and the like of a denitration device are easily caused. (2) downstream equipment plugging corrosion problems; because the ammonia water is sprayed into the decomposing furnace to carry out SNCR reaction, if the ammonia escape is improperly controlled, the problems of blockage, corrosion, reduced heat efficiency and the like of the waste heat boiler are easily caused. (3) The technical scheme can not meet the requirement that SO can be met in the starting stage of the cement line2、NOxThe commissioning conditions of (1).
In conclusion, in the face of increasingly strict ultra-low emission requirements of the cement industry, it is of great significance to develop a desulfurization and denitrification integrated device which is low in consumption and can stably operate for a long time.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model aims at providing a dry process SOx/NOx control device suitable for cement kiln flue gas can alleviate dust, CaO and SO when high-efficient SOx/NOx control2The pollutants such as the nitrogen and the nitrogen poison to the catalyst reduce the system blockage and abrasion, ensure the long-term stable operation of the whole device and simultaneously ensure the desulfurization and denitrification under all working conditions.
The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas, include:
the cement kiln, the preheater and the waste heat boiler are connected in sequence;
the inlet flue is connected with a discharge port of the waste heat boiler; the inlet flue is sequentially provided with a flue gas circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
the feed inlet is connected with the discharge outlet of the desulfurization absorption tower; a dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline;
the feed inlet is connected with a low-sulfur and low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side of the SCR denitration device is provided with a soot blowing device, and a bottom purified gas outlet is connected with a second flue gas pipeline;
the chimney is connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation air outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation air outlet is communicated with a feed inlet of the ammonia spraying device;
and the purified gas circulating outlet is respectively communicated with the flue gas circulating inlet I and the flue gas circulating inlet II.
Preferably, the dust removal material outlet is also connected with a desulfurization byproduct discharge outlet.
Preferably, the flue gas circulation inlet is respectively communicated with the flue gas circulation inlet II and the purified gas circulation outlet through a third flue gas pipeline; and the third flue gas pipeline is provided with a recirculation damper.
Preferably, the flue gas circulation inlet II is communicated with a third flue gas pipeline through a fourth flue gas pipeline; and the fourth flue gas pipeline is provided with a damper for desulfurization and recirculation.
Preferably, the SCR denitration device is matched with a medium-low temperature catalyst, and the temperature of a reaction window is 80-280 ℃.
Preferably, the method further comprises the following steps:
and the GGH heat exchangers are arranged on the first flue gas pipeline and the second flue gas pipeline.
The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas, include: the cement kiln, the preheater and the waste heat boiler are connected in sequence; the inlet flue is connected with a discharge port of the waste heat boiler; the inlet flue is sequentially provided with a flue gas circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun; the feed inlet is connected with the discharge outlet of the desulfurization absorption tower; the dust removalA dedusting material outlet of the device is communicated with the dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline; the feed inlet is connected with a low-sulfur and low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side of the SCR denitration device is provided with a soot blowing device, and a bottom purified gas outlet is connected with a second flue gas pipeline; the chimney is connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation air outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation air outlet is communicated with a feed inlet of the ammonia spraying device; and the flue gas circulation inlet I is respectively communicated with the flue gas circulation inlet II and the purified gas circulation outlet. Compared with the prior art, the utility model provides a dry process SOx/NOx control device is applicable to the cement kiln flue gas, can alleviate dust, CaO and SO when high-efficient SOx/NOx control that removes dust2The pollutants such as the nitrogen and the nitrogen poison to the catalyst reduce the system blockage and abrasion, ensure the long-term stable operation of the whole device and simultaneously ensure the desulfurization and denitrification under all working conditions. Experimental result shows, the utility model provides a dry process SOx/NOx control device's desulfurization efficiency can reach more than 99%, and denitration efficiency can reach more than 95%, and SO2、NOxThe discharge concentration is respectively lower than 10mg/Nm3、50mg/Nm3The ultra-low emission is realized; and the dust concentration is less than 5mg/Nm3。
Additionally, the utility model provides a supporting GGH gas heater of dry process SOx/NOx control device alternative to practice thrift the heating energy consumption, have wide application prospect.
Drawings
FIG. 1 is a schematic structural diagram of a dry desulfurization and denitrification apparatus suitable for cement kiln flue gas provided by an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a dry desulfurization and denitrification apparatus suitable for cement kiln flue gas provided in embodiment 1 of the present invention;
fig. 3 is the utility model discloses the dry desulfurization and denitrification facility's that is applicable to cement kiln flue gas that embodiment 2 provided structural schematic diagram.
Detailed Description
The technical solution of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, and it should be understood that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas, include:
the cement kiln, the preheater and the waste heat boiler are connected in sequence;
the inlet flue is connected with a discharge port of the waste heat boiler; the inlet flue is sequentially provided with a flue gas circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
the feed inlet is connected with the discharge outlet of the desulfurization absorption tower; a dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline;
the feed inlet is connected with a low-sulfur and low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side of the SCR denitration device is provided with a soot blowing device, and a bottom purified gas outlet is connected with a second flue gas pipeline;
the chimney is connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation air outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation air outlet is communicated with a feed inlet of the ammonia spraying device;
and the purified gas circulating outlet is respectively communicated with the flue gas circulating inlet I and the flue gas circulating inlet II.
Referring to fig. 1, fig. 1 is a schematic structural diagram of a dry desulfurization and denitrification apparatus suitable for cement kiln flue gas provided in embodiment 1 of the present invention; wherein, 1 is a cement kiln, 2 is a preheater, 3 is a waste heat boiler, 4 is an inlet flue, 5 is a discharge port of the waste heat boiler, 6 is a desulfurization absorption tower, 7 is a flue gas circulation inlet I, 8 is a dedusting material circulation inlet, 9 is an absorbent inlet, 10 is a water spray gun, 11 is a feed inlet of a dust remover, 12 is a discharge port of the desulfurization absorption tower, 13 is a dust remover, 14 is a dedusting material outlet, 15 is an air chute, 16 is a low-dust flue gas outlet, 17 is a first flue gas pipeline, 18 is a feed inlet of an SCR denitration device, 19 is an SCR denitration device, 20 is a denitration inlet windshield, 21 is a flue gas circulation inlet II, 22 is a heating device, 23 is an ammonia spraying device, 24 is a rectifying device, 25 is a soot blowing device, 26 is a purified gas outlet, 27 is a second flue gas pipeline, 28 is a chimney, 29 is an ammonia water evaporation air outlet, 30 is a draught fan, and 31 is a purified gas circulation outlet, and 32 is a feed inlet of the ammonia spraying device.
The utility model discloses in, dry process SOx/NOx control device includes cement kiln (1), pre-heater (2), exhaust-heat boiler (3), desulfurization absorption tower (6), dust remover (13), SCR denitrification facility (19) and chimney (28). In the utility model, the cement kiln (1), the preheater (2) and the waste heat boiler (3) are connected in sequence; the cement kiln flue gas can enter the waste heat boiler (3) after being preheated by the preheater (2) from the cement kiln (1), and the heat in the cement kiln flue gas is recycled as much as possible in the waste heat boiler (3). In the utility model discloses, exhaust-heat boiler (3) are equipped with discharge gate (5).
The utility model discloses in, exhaust-heat boiler (3) set up before desulfurization absorption tower (6), can guarantee the waste heat recovery efficiency in the flue gas as far as possible to avoid SCR denitrification facility (19) to set up because spouting ammonia before exhaust-heat boiler (3), ammonium bisulfite forms the emergence that arouses the jam, corrosion scheduling problem.
In the utility model, the desulfurization absorption tower (6) is used for desulfurizing flue gas; and an inlet flue (4) is arranged at the bottom of the desulfurization absorption tower (6), a discharge hole (12) is formed in the top of the desulfurization absorption tower, and a water spray gun (10) is arranged at the position, close to the inlet flue (4), of the lower part of the desulfurization absorption tower. The utility model discloses in, entry flue (4) link to each other with discharge gate (5) of exhaust-heat boiler (3) to the flue gas that can make in exhaust-heat boiler (3) gets into desulfurization absorption tower (6) through entry flue (4).
In the utility model, the inlet flue (4) is provided with a flue gas circulation inlet I (7), a dedusting material circulation inlet (8) and an absorbent inlet (9) in sequence; the absorbent inlet (9) is connected with the absorbent bin and is used for introducing the absorbent in the absorbent bin into the inlet flue (4). In the utility model, the absorbent is preferably calcium-based alkaline absorbent which can be matched with SO in the flue gas entering the desulfurization absorption tower (6)2、SO3、HCl、NO2And the pollutants are removed through rapid reaction. The utility model discloses a dry desulfurization, the solid double-phase because the effect of air current produces violent torrent and mix in desulfurization absorption tower (6), and abundant contact has greatly strengthened mass transfer and the heat transfer between the gas-solid, guarantees the abundant absorption desorption of above-mentioned acidic material.
The utility model discloses in, the temperature that water spray gun (10) are used for controlling discharge gate (12) of desulfurization absorption tower (6) is 70 ℃ -110 ℃, avoids high temperature flue gas to damage the rear end sack when guaranteeing high-efficient desulfurization, stabilizes the long-term steady operation of the temperature denitration device of being convenient for of follow-up denitration entry.
In the utility model, the dust remover (13) is used for removing dust from the desulfurized flue gas, collecting the flue gas and unreacted materials, and obtaining low-sulfur and low-dust flue gas; the dust remover (13) is preferably a bag-type dust remover. In the utility model, the dust remover (13) is provided with a feed inlet (11), a dust removing material outlet (14) and a low-sulfur and low-dust flue gas outlet (16); the feed inlet (11) is connected with a discharge hole (12) of the desulfurization absorption tower (6) and is used for introducing the desulfurized flue gas into a dust remover (13).
The utility model discloses in, dust remover (13) set up SCR denitrification facility (19) are preceding, can reduce dust, CaO and SO in the flue gas in a large number2To realize NO removal of flue gas when entering an SCR denitration device (19)xBesides, other pollutants are ultra-clean, so that the damage of the pollutants to the catalyst can be greatly reduced, and the increase of the damage to the catalystThe service life of the catalyst.
The utility model discloses in, dust removal material export (14) through air chute (15) with dust removal material circulation entry (8) communicate with each other for circulate dust removal material to enter into desulfurization absorption tower (6) after entry flue (4) and carry out the desulfurization again. The utility model discloses in, dust removal material export (14) are preferred still to be connected with desulfurization byproduct external row mouth for arrange partial dust removal material outward.
In the utility model, the low-sulfur and low-dust flue gas outlet (16) is connected with a first flue gas pipeline (17).
The utility model discloses in, SCR denitrification facility (19) are used for carrying out the SCR denitration, obtain the purified gas. In the utility model, the SCR denitration device (19) is provided with a feed inlet (18) and a purified gas outlet (26), the top of the SCR denitration device is provided with a rectifying device (24), and the side part of the SCR denitration device is provided with a soot blower (25); wherein the feed inlet (18) is connected with a low-sulfur and low-dust flue gas outlet (16) of the dust remover (13) through the first flue gas pipeline (17); the sootblower (25) is preferably a steam/sound wave sootblower. In the utility model, the first flue gas pipeline (17) is sequentially provided with a denitration inlet windshield (20), a flue gas circulation inlet II (21), a heating device (22) and an ammonia spraying device (23); the heating device (22) is used for carrying out temperature control on low-sulfur and low-dust flue gas; and the ammonia injection device (23) is used for injecting gasified ammonia water into the SCR denitration device (19).
The utility model discloses in, purified gas export (26) set up in SCR denitrification facility (19) bottom, connect second flue gas pipeline (27).
In the utility model, the rectifying device (24) can ensure the SCR denitration device (19) to run more stably; the soot blower (25) is used for periodically cleaning the catalyst to prevent soot deposition.
In the present invention, the chimney (28) is used for discharging purified gas; the chimney (28) is connected with a purified gas outlet (26) of the SCR denitration device (19) through the second flue gas pipeline (27). In the utility model, the second flue gas pipeline (27) is provided with an ammonia water evaporation air outlet (29), a draught fan (30) and a purified gas circulation outlet (31) in sequence; the ammonia water evaporation air outlet (29) is communicated with a feed inlet (32) of the ammonia spraying device (23) and is used for realizing ammonia evaporation.
The utility model discloses in, draught fan (30) are used for providing power for the flue gas. In the utility model, the flue gas circulation inlet I (7) is respectively communicated with the flue gas circulation inlet II (21) and the purified gas circulation outlet (31); preferably, the flue gas circulation inlet I (7) is respectively communicated with the flue gas circulation inlet II (21) and the purified gas circulation outlet (31) through a third flue gas pipeline. In the utility model discloses, the third flue gas pipeline is preferred to be equipped with the recirculation windshield. In the utility model, the flue gas circulation inlet II (21) is preferably communicated with the third flue gas pipeline through a fourth flue gas pipeline; the fourth flue gas pipeline is preferably provided with a damper for the desulfurization recirculation. The utility model discloses under draught fan (30) effect (if utilize both ends pressure differential), can be according to the front end load smoke gas volumn situation of change, the baffle aperture of adjustment recirculation windshield and past desulfurization recirculation windshield to guarantee the stability of different load operating mode lower systems.
In addition, above-mentioned third flue gas pipeline and fourth flue gas pipeline's being connected can also realize purifying gas circulation export (31) through the fourth flue gas pipeline with flue gas circulation entry II (21) link to each other, are favorable to more quick preheating SCR denitrification facility, and concrete process is:
before starting the machine, firstly closing the denitration inlet windshield (20) and the recycling windshield, opening the recycling windshield to desulfurization, then opening the draught fan (30), opening the heating device (22), cooling the recycling hot flue gas without passing through the desulfurization absorption tower (6) and the dust remover (13), preheating the SCR denitration device (19) more quickly, opening the desulfurization recycling windshield (17) before starting the machine in sintering, closing or reducing the denitration inlet windshield (20), desulfurizing in advance to build a bed, and meeting the time required by bed building, thereby meeting the desulfurization and denitration operation under the starting working condition and the low-load working condition; like this on the one hand SCR denitrification facility (19) preheat the time, the hot flue gas heat dissipation loss of recirculation is littleer, can preheat more fast, and on the other hand preheats the period, the recirculated flue gas does not pass through desulfurization absorption tower (6) and dust remover (13), and the resistance is littleer, can practice thrift the denitration and preheat the time energy consumption.
The utility model discloses in, dry process SOx/NOx control device still includes:
the GGH heat exchangers are arranged on the first flue gas pipeline (17) and the second flue gas pipeline (27); the low-sulfur low-dust flue gas (low-temperature gas) discharged from a low-sulfur low-dust flue gas outlet (16) of the dust remover (13) exchanges heat with the purified gas (high-temperature gas) discharged from a purified gas outlet (26) of the SCR denitration device (19), so that heating energy consumption is saved, and whether the GGH heat exchanger is matched or not can be selected according to the temperature of a reaction window of the selected catalyst.
The utility model provides a dry desulfurization and denitrification device is applicable to the cement kiln flue gas, can alleviate dust, CaO and SO when high-efficient desulfurization dust removal denitration2The pollutants such as the nitrogen and the nitrogen poison to the catalyst reduce the system blockage and abrasion, ensure the long-term stable operation of the whole device and simultaneously ensure the desulfurization and denitrification under all working conditions. Experimental result shows, the utility model provides a dry process SOx/NOx control device's desulfurization efficiency can reach more than 99%, and denitration efficiency can reach more than 95%, and SO2、NOxThe discharge concentration is respectively lower than 10mg/Nm3、 50mg/Nm3The ultra-low emission is realized; and the dust concentration is less than 5mg/Nm3。
Additionally, the utility model provides a dry process SOx/NOx control device can form a complete set GGH gas heater to practice thrift the heating energy consumption, have wide application prospect.
The utility model also provides a dry process SOx/NOx control method suitable for cement kiln flue gas, adopt above-mentioned technical scheme dry process SOx/NOx control device, including following step:
a) preheating the cement kiln flue gas, performing dry desulfurization under the action of an absorbent, and then removing dust to respectively obtain a dust-removed material and low-sulfur and low-dust flue gas; wherein the dedusting material is circularly subjected to the dry desulphurization;
b) carrying out SCR denitration on the low-sulfur and low-dust flue gas obtained in the step a) at the temperature of 70-280 ℃ in the presence of ammonia water to obtain purified gas.
The utility model discloses at first preheat the back with cement kiln flue gas, carry out the dry process desulfurization under the absorbent effect, remove dust again, obtain dust removal material and low sulfur low dust flue gas respectively. The utility model is right of cementThe source of the kiln flue gas is not particularly limited and may be cement kiln flue gas known to those skilled in the art. In the preferred embodiment of the present invention, NO in the flue gas of the cement kilnxPreferably at a concentration of 100mg/Nm3～2000mg/Nm3More preferably 400mg/Nm3～1500mg/Nm3(ii) a SO in the cement kiln flue gas2Preferably at a concentration of 100mg/Nm3～1500mg/Nm3More preferably 400mg/Nm3～1000mg/Nm3。
The utility model discloses in, the process of preheating is gone on in preheater (2) that link to each other with cement kiln (1) to retrieve the heat in the cement kiln flue gas as far as possible in exhaust-heat boiler (3). In the present invention, the absorbent is preferably a calcium-based alkaline absorbent, more preferably Ca (OH)2(ii) a The absorbent can be mixed with SO in the cement kiln flue gas2、SO3、HCl、NO2And the pollutants are removed through rapid reaction. The source of the calcium-based alkaline absorbent is not particularly limited, and commercially available products known to those skilled in the art may be used. In the present invention, the absorbent is preferably a calcium-based alkaline absorbent; the full absorption and removal of the acidic substances are ensured by utilizing the extremely large mass transfer and heat transfer between gas and solid.
In the utility model, the dry desulfurization process is carried out in the desulfurization absorption tower (6), and the reaction temperature is controlled by spraying water through the water spray gun (10). In the present invention, the outlet temperature of the dry desulfurization is preferably 70 to 110 ℃.
In the utility model, the dust removal process is carried out in a dust remover (13) to respectively obtain dust removal materials and low-sulfur and low-dust flue gas; wherein the dedusting material is circulated for the above-mentioned dry desulphurization.
Obtain behind the low sulphur low dust flue gas, the utility model discloses the low sulphur low dust flue gas that will obtain carries out the SCR denitration at 80 ℃ -280 ℃, under the aqueous ammonia existence, obtains the purified gas. The utility model discloses in, the process of SCR denitration is gone on in SCR denitrification facility (19). The utility model discloses carry out the denitration of well low temperature SCR under above-mentioned temperature, the operation is stable, and the denitration is efficient.
The utility model discloses in, the preferred recirculation of part of the purified gas circulation that obtains in step b) is got back to and is helped desulfurization absorption tower (6) and SCR denitrification facility (19) and assist dry process desulfurization and preheat.
The utility model discloses in, the dry process SOx/NOx control method is preferred still to include:
and (b) carrying out heat exchange on the low-sulfur and low-dust flue gas obtained in the step a) and the purified gas obtained in the step b), and then carrying out SCR denitration. In the utility model, the heat exchange process is preferably carried out in the GGH heat exchanger; therefore, the heating energy consumption is saved, and the catalyst can be selected and matched according to the temperature of the reaction window of the selected catalyst.
The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas, include: the cement kiln, the preheater and the waste heat boiler are connected in sequence; the inlet flue is connected with a discharge port of the waste heat boiler; the inlet flue is sequentially provided with a flue gas circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun; the feed inlet is connected with the discharge outlet of the desulfurization absorption tower; a dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline; the feed inlet is connected with a low-sulfur and low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side of the SCR denitration device is provided with a soot blowing device, and a bottom purified gas outlet is connected with a second flue gas pipeline; the chimney is connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation air outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation air outlet is communicated with a feed inlet of the ammonia spraying device; and the flue gas circulation inlet I is respectively communicated with the flue gas circulation inlet II and the purified gas circulation outlet. Compared with the prior art, the utility model provides a dry process SOx/NOx control device is applicable to the cement kiln flue gas, can alleviate the dust when high-efficient SOx/NOx control that removes dustCaO and SO2The pollutants such as the nitrogen and the nitrogen poison to the catalyst reduce the system blockage and abrasion, ensure the long-term stable operation of the whole device and simultaneously ensure the desulfurization and denitrification under all working conditions. Experimental result shows, the utility model provides a dry process SOx/NOx control device's desulfurization efficiency can reach more than 99%, and denitration efficiency can reach more than 95%, and SO2、NOxThe discharge concentration is respectively lower than 10mg/Nm3、50mg/Nm3The ultra-low emission is realized; and the dust concentration is less than 5mg/Nm3。
Additionally, the utility model provides a dry process SOx/NOx control device can form a complete set GGH gas heater to practice thrift the heating energy consumption, have wide application prospect.
To further illustrate the present invention, the following examples are given in detail. The cement kiln smoke used in the following embodiments of the utility model is from a cement kiln of 5000t/d, and the smoke amount is 380000Nm3H (standard condition), NO in cement kiln smokexAt a concentration of 400mg/Nm3～1500mg/Nm3，SO2At a concentration of 400mg/Nm3～1000mg/Nm3. The absorbent is Ca (OH)2The denitration reducing agent is ammonia water.
Example 1
The structural schematic diagram of the dry desulfurization and denitrification device suitable for the cement kiln flue gas provided by the embodiment 1 is shown in fig. 2; wherein, 1 is a cement kiln, 2 is a preheater, 3 is a waste heat boiler, 4 is a discharge hole of the waste heat boiler, 6 is a desulfurization absorption tower, 7 is a flue gas circulation inlet I, 8 is a dedusting material circulation inlet, 9 is an absorbent inlet, 10 is a water spray gun, 11 is a feed inlet of a deduster, 12 is a discharge hole of the desulfurization absorption tower, 13 is a deduster, 14 is a dedusting material outlet, 15 is an air chute, 16 is a low-sulfur and low-dust flue gas outlet, 17 is a first flue gas pipeline, 18 is a feed inlet of an SCR denitration device, 19 is an SCR denitration device, 20 is a denitration inlet windshield, 21 is a flue gas circulation inlet II, 22 is a heating device, 23 is an ammonia spraying device, 24 is a rectifying device, 25 is a soot blowing device, 26 is a purified gas outlet, 27 is a second flue gas pipeline, 28 is a chimney, 29 is an ammonia water evaporation air outlet, 30 is a draught fan, 31 is a purified gas circulation outlet, and 32 is a feed inlet of the ammonia spraying device, 33 is an outer discharge port of the desulfurization byproducts, 34 is a third flue gas pipeline, 35 is a recirculation damper, 36 is a fourth flue gas pipeline, and 37 is a damper for recycling to desulfurization.
The dry desulfurization and denitrification device is adopted for desulfurization, dust removal and denitrification of the flue gas of the cement kiln, and the specific working process is as follows:
(1) preheating cement kiln flue gas by a cement kiln (1) through a preheater (2), then feeding the cement kiln flue gas into a waste heat boiler (3), recovering heat in the cement kiln flue gas as much as possible in the waste heat boiler (3), then feeding the cement kiln flue gas into a desulfurization absorption tower (6) through a discharge hole (5) of the waste heat boiler (3) from an inlet flue (4), performing dry desulfurization under the action of an absorbent, controlling the temperature by a water spray gun (10) to enable the outlet temperature of the desulfurized flue gas to be 70-110 ℃, and then feeding the cement kiln flue gas into a dust remover (13) through a feed hole (11) of the dust remover (13) for dust removal to respectively obtain a dust removal material and low-sulfur and low-dust flue gas; the dedusting material enters the inlet flue (4) from the dedusting material circulating inlet (8) through the dedusting material outlet (14) and the air chute (15), and is recycled for the dry desulphurization.
(2) Controlling the temperature of the low-sulfur and low-dust flue gas obtained in the step (1) to be 70-150 ℃ through a heating device (22), enabling the low-sulfur and low-dust flue gas to enter an SCR denitration device (19), carrying out SCR denitration on the SCR denitration device (19) by adopting a low-temperature catalyst (a reaction window is 70-150 ℃) in the presence of ammonia water, spraying the ammonia water into the SCR denitration device (19) after the ammonia water is evaporated and diluted by an ammonia spraying device (23) to obtain purified gas, and finally discharging the purified gas into a chimney (28) through a draught fan (30);
in addition, in order to prevent dust deposition, the SCR denitration device (19) is matched with a soot blower (25) to periodically perform ash removal treatment on the catalyst.
Example 2
The schematic structural diagram of the dry desulfurization and denitrification device suitable for cement kiln flue gas provided in example 2 is shown in fig. 3; wherein, 1 is a cement kiln, 2 is a preheater, 3 is a waste heat boiler, 4 is a discharge hole of the waste heat boiler, 6 is a desulfurization absorption tower, 7 is a flue gas circulation inlet I, 8 is a dedusting material circulation inlet, 9 is an absorbent inlet, 10 is a water spray gun, 11 is a feed inlet of a deduster, 12 is a discharge hole of the desulfurization absorption tower, 13 is a deduster, 14 is a dedusting material outlet, 15 is an air chute, 16 is a low-sulfur and low-dust flue gas outlet, 17 is a first flue gas pipeline, 18 is a feed inlet of an SCR denitration device, 19 is an SCR denitration device, 20 is a denitration inlet windshield, 21 is a flue gas circulation inlet II, 22 is a heating device, 23 is an ammonia spraying device, 24 is a rectifying device, 25 is a soot blowing device, 26 is a purified gas outlet, 27 is a second flue gas pipeline, 28 is a chimney, 29 is an ammonia water evaporation air outlet, 30 is a draught fan, 31 is a purified gas circulation outlet, and 32 is a feed inlet of the ammonia spraying device, 33 is an external discharge port of the desulfurization by-products, 34 is a third flue gas pipeline, 35 is a recirculation damper, 36 is a fourth flue gas pipeline, 37 is a damper for desulfurization recirculation, and 38 is a GGH heat exchanger.
The dry desulfurization and denitrification device is adopted for desulfurization, dust removal and denitrification of the flue gas of the cement kiln, and the specific working process is as follows:
(1) preheating cement kiln flue gas by a cement kiln (1) through a preheater (2), then feeding the cement kiln flue gas into a waste heat boiler (3), recovering heat in the cement kiln flue gas as much as possible in the waste heat boiler (3), then feeding the cement kiln flue gas into a desulfurization absorption tower (6) through a discharge hole (5) of the waste heat boiler (3) from an inlet flue (4), performing dry desulfurization under the action of an absorbent, controlling the temperature by a water spray gun (10) to enable the outlet temperature of the desulfurized flue gas to be 90-100 ℃, and then feeding the desulfurized flue gas into a dust remover (13) through a feed hole (11) of the dust remover (13) for dust removal to respectively obtain a dust removal material and low-sulfur and low-dust flue gas; the dedusting material enters the inlet flue (4) from the dedusting material circulating inlet (8) through the dedusting material outlet (14) and the air chute (15), and is recycled for the dry desulphurization.
(2) After the low-sulfur and low-dust flue gas obtained in the step (1) is subjected to heat exchange through a GGH heat exchanger (38), the temperature is raised to 250 ℃, then the temperature is controlled to be 250-280 ℃ through a heating device (22), the flue gas enters an SCR denitration device (19), the SCR denitration device (19) adopts a medium-temperature catalyst (a reaction window is 230-280 ℃), SCR denitration is carried out in the presence of ammonia water, the ammonia water is evaporated and diluted through an ammonia spraying device (23) and then sprayed into the SCR denitration device (19), purified gas is obtained, the purified gas is subjected to heat exchange with the low-sulfur and low-dust flue gas through the GGH heat exchanger (38), the temperature is reduced to 120 ℃, and finally the purified gas is discharged into a chimney (28);
in addition, in order to prevent dust deposition, the SCR denitration device (19) is matched with a soot blower (25) to periodically perform ash removal treatment on the catalyst.
Through detection, the desulfurization efficiency of the dry desulfurization and denitrification device provided by the embodiment 1 and the embodiment 2 of the utility model can reach more than 99%, and the denitrification efficiency can reach more than 95%; after the dry desulfurization and denitrification device is adopted to carry out desulfurization, dedusting and denitrification on the cement kiln flue gas, SO in the obtained purified gas2、NOxThe discharge concentration is respectively lower than 10mg/Nm3、50mg/Nm3The ultra-low emission is realized; and the dust concentration is less than 5mg/Nm3。
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. The utility model provides a dry process SOx/NOx control device suitable for cement kiln flue gas which characterized in that includes:
the cement kiln, the preheater and the waste heat boiler are connected in sequence;
the inlet flue is connected with a discharge port of the waste heat boiler; the inlet flue is sequentially provided with a flue gas circulation inlet I, a dedusting material circulation inlet and an absorbent inlet; the desulfurization absorption tower is provided with a water spray gun;
the feed inlet is connected with the discharge outlet of the desulfurization absorption tower; a dedusting material outlet of the deduster is communicated with the dedusting material circulating inlet through an air chute, and a low-sulfur and low-dust flue gas outlet is connected with a first flue gas pipeline;
the feed inlet is connected with a low-sulfur and low-dust flue gas outlet of the dust remover through the first flue gas pipeline; the first flue gas pipeline is sequentially provided with a denitration inlet windshield, a flue gas circulation inlet II, a heating device and an ammonia spraying device; the top of the SCR denitration device is provided with a rectifying device, the side of the SCR denitration device is provided with a soot blowing device, and a bottom purified gas outlet is connected with a second flue gas pipeline;
the chimney is connected with a purified gas outlet of the SCR denitration device through the second flue gas pipeline; the second flue gas pipeline is sequentially provided with an ammonia water evaporation air outlet, an induced draft fan and a purified gas circulation outlet; the ammonia water evaporation air outlet is communicated with a feed inlet of the ammonia spraying device;
and the purified gas circulating outlet is respectively communicated with the flue gas circulating inlet I and the flue gas circulating inlet II.
2. The dry desulfurization and denitrification apparatus according to claim 1, wherein the dedusting material outlet is further connected with a desulfurization byproduct discharge outlet.
3. The dry desulfurization and denitrification device according to claim 1, wherein the flue gas circulation inlet is respectively communicated with the flue gas circulation inlet II and the purified gas circulation outlet through a third flue gas pipeline; and the third flue gas pipeline is provided with a recirculation damper.
4. The dry desulfurization and denitrification device according to claim 1, wherein the SCR denitrification device is matched with a medium-low temperature catalyst, and the temperature of a reaction window is 80-280 ℃.
5. The dry desulfurization and denitrification device according to claim 3, wherein the flue gas circulation inlet II is communicated with a third flue gas pipeline through a fourth flue gas pipeline; and the fourth flue gas pipeline is provided with a damper for desulfurization and recirculation.
6. The dry desulfurization and denitrification apparatus according to claim 1, further comprising:
and the GGH heat exchangers are arranged on the first flue gas pipeline and the second flue gas pipeline.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110075681A (en) * | 2019-06-12 | 2019-08-02 | 福建龙净脱硫脱硝工程有限公司 | A kind of dry desulfurization denitrification apparatus and method suitable for cement kiln flue gas |
| CN112316712A (en) * | 2020-09-30 | 2021-02-05 | 成都易态科技有限公司 | Waste incineration flue gas treatment system and treatment method |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110075681A (en) * | 2019-06-12 | 2019-08-02 | 福建龙净脱硫脱硝工程有限公司 | A kind of dry desulfurization denitrification apparatus and method suitable for cement kiln flue gas |
| CN110075681B (en) * | 2019-06-12 | 2024-05-28 | 福建龙净脱硫脱硝工程有限公司 | Dry desulfurization and denitrification device and method suitable for cement kiln flue gas |
| CN112316712A (en) * | 2020-09-30 | 2021-02-05 | 成都易态科技有限公司 | Waste incineration flue gas treatment system and treatment method |
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