CN116123878A - Novel water-cooled bypass air release coupling SNCR system - Google Patents

Abstract

The invention discloses a novel water-cooled bypass air release coupling SNCR system which is used for treating flue gas in a flue gas chamber of a decomposing furnace, and comprises a rising pipeline, an SNCR ammonia spraying device, a cyclone, a quenching component, a dust collector and an exhaust fan, wherein the flue gas in the flue gas chamber sequentially flows through the rising pipeline, the cyclone, the quenching component and the dust collector; the SNCR ammonia spraying device is arranged on the ascending pipeline; coarse ash separated by the cyclone in the flue gas is sent back to the decomposing furnace, and then purified by the dust collector and discharged into a kiln tail chimney by the exhaust fan. The invention carries out harmless treatment on excessive harmful components in the cement kiln system, and solves the skinning blocking phenomenon caused by the cyclic enrichment of the harmful components in the system. The bypass ventilation system in the water cooling mode reduces the system air quantity, optimizes the equipment model selection, and simultaneously compared with the traditional process route, the cyclone is arranged in front of the quenching chamber, so that the SNCR reaction residence time is sufficient, the low-chlorine coarse ash is replayed, and the influence on the kiln system output is reduced.

Description

A new type of water-cooled bypass ventilation coupled SNCR system

technical field

The invention relates to the technical field of cement kiln co-processing, in particular to a novel water-cooled bypass ventilation coupling SNCR system.

Background technique

In recent years, my country's cement industry has actively participated in the harmless and resourceful disposal of urban and rural solid waste. However, in the process of co-processing urban and rural solid waste in cement kilns, solid waste contains more harmful components, which may have serious consequences on the normal operation of various systems and equipment in cement kilns and the quality of cement products. Co-processed waste generally brings in more harmful components such as potassium, sodium, sulfur, and chlorine. The harmful components brought in will not only be enriched in the system, cause crust blockage, and affect the stable operation of the cement kiln production system. , but also have adverse effects on clinker quality.

The main process of the traditional bypass ventilation system is: extracting high-temperature flue gas at 1100°C from the flue gas chamber, cooling it to 350°C through the quenching chamber mixed with cold air or water cooling, and then entering the cyclone to separate coarse and fine particles, and then entering the heat exchanger for secondary After cooling, it enters the bag for dust collection and purification, and is discharged to the chimney by the exhaust fan. Some process technology routes will add SNCR devices before the quench chamber.

Its disadvantages are as follows:

1. In the conventional process, the high-temperature flue gas extracted from the smoke chamber is quenched first, and then sent to the cyclone after cooling to 350°C. The harmful elements are enriched on the ash through rapid cooling, and the cyclone will account for more than 80% of the coarse ash Send it back to the cement kiln, send more than 20% of the fine ash into the dust collector and discharge it outside, among which Cl ^- and other harmful elements in 80% of the coarse ash have been enriched by the impact of rapid cooling, Cl ^- ≥ 5%, and then return The cycle of harmful elements will be caused in the kiln, which will reduce the effect of air release. If the kiln is not returned, the amount of ash released will be too large (affected by the specific surface area, the enrichment effect of fine ash on Cl ^- is better than that of coarse ash, and Cl ^- in fine ash content more than 15%)

2. Part of the process technology route installs the SNCR device between the quench chamber and the smoke chamber. Due to the limitation of the installation position of the quench chamber, the distance between it and the smoke chamber is very short, which will cause the SNCR reaction window time to be very short ( less than 0.2s), the denitrification efficiency is ≤10%, and because there is no temperature adjustment chamber, at a high temperature of 1100°C, part of the ammonia water will be oxidized into _NOx , which will increase the emission of _NOx instead.

3. The traditional bypass ventilation system needs to be mixed with a large amount of cold air, resulting in a large selection of follow-up equipment, which not only increases the investment cost of equipment, but also needs to occupy a certain space, which increases the difficulty of design and layout, and the heat exchange effect is mediocre.

4. If SCR is installed in the bypass ventilation system, the investment will be greatly increased, which is uneconomical.

Therefore, it is necessary to provide a novel water-cooled bypass ventilation coupling SNCR system to solve the problems raised in the above-mentioned background technology.

Contents of the invention

In order to achieve the above object, the present invention provides the following technical solutions: a novel water-cooled bypass ventilation coupling SNCR system, used to process the flue gas in the flue gas chamber of the calciner, including an ascending pipe, an SNCR ammonia injection device, a cyclone, Quenching component, dust collector and exhaust fan, wherein the flue gas in the flue gas chamber flows through the ascending pipe, cyclone, quenching component and dust collector in sequence;

The SNCR ammonia injection device is arranged on the ascending pipeline;

The coarse ash separated by the cyclone in the flue gas is sent back to the calciner, and then the fine dust is purified by the dust collector and then discharged into the chimney at the end of the kiln through the exhaust fan.

Further, preferably, the distance between the cyclone and the flue gas chamber is ≥20m, so as to ensure that the residence time of the flue gas therein is ≥2.5s.

Further, as a preference, a temperature adjustment chamber is provided at the front end of the SNCR ammonia injection device to keep the temperature in the pipeline between 850°C and 920°C.

Further, as a preference, the reducing agent in the SNCR ammonia injection device is ammonia water with a concentration ≥ 20%, and the spray gun is an L-shaped two-fluid spray gun.

Further, preferably, the quenching component is water-cooled, and can quench the high-temperature flue gas to 180°C-220°C within 2-4s.

Further, as a preference, the quenching assembly includes a quenching chamber, an air induction pipe, a heat soaking tube group and a heat exchange tube, wherein a heat exchange tube is embedded in the quenching chamber, and the inlet end of the heat exchange pipe adopts a heat soaking pipe group and a heat exchange tube. The air pipes are connected, the heat soaking pipe group is located outside the quenching chamber, the air induction pipe is located inside the quenching chamber, and the top of the quenching chamber is equipped with a spray pipe for spraying cooling liquid into the quenching chamber. The bottom of the quench chamber is also provided with a collecting pipe for discharging cooling liquid.

Further, as a preference, the heat equalizing pipe group includes an extension pipe, a heat equalizing pipe and a sleeve, wherein one end of the extension pipe communicates with the air induction pipe, and the other end communicates with the sleeve through a heat equalizing pipe, and the extension pipe Together with the heat soaking tube, it can form a back-shaped tube body with a gap, and a part of the tube body of the casing is sleeved on a part of the tube body of the heat soaking tube, and communicated with the inlet end of the heat exchange tube.

Further, as a preference, the heat exchange tubes are configured as a plurality of vertically arranged ones, the tops of the multiple heat exchange tubes all converge on the horizontal tube serving as the inlet end of the heat exchange tubes, and the bottoms of the multiple heat exchange tubes pass through The super-quick cooling chamber is collected to the exhaust pipe as the outlet end of the heat exchange tube, and the exhaust pipe is connected to the dust collector; the sliding sleeve on each heat exchange tube is equipped with an external cleaning assembly, which can float in the cooling liquid superior.

Further, as a preference, a baffle is also arranged horizontally in the quench chamber, through which the heat exchange tubes can be separated into two upper and lower liquid control spaces, and each liquid control space is connected to the collecting pipe by a liquid control pipe, The liquid control pipe is provided with a valve body, and the liquid control space below is also supplied with liquid by an external liquid supply assembly.

Further, preferably, the outer cleaning assembly includes a cleaning sleeve, the inner surface of the cleaning sleeve has teeth, the outer surface of the cleaning sleeve is fixed with a floating ball, and the outer cleaning assembly can be floated in the cooling liquid through the floating ball Above, a plurality of through pipes are embedded in the middle of the cleaning sleeve.

Compared with the prior art, the present invention provides a novel water-cooled bypass ventilation coupling SNCR system, which has the following beneficial effects:

1. The process flow is simple, the equipment selection is optimized, and the project infrastructure investment is reduced;

2. By arranging the cyclone before the quenching chamber, taking advantage of the height of the cyclone, the reaction window time of SNCR is extended, and the efficiency of SNCR is improved.

3. Using water-cooled quenching chamber to reduce the flue gas temperature, the cooling rate and effect are better than air cooling;

4. The cyclone is set before the quenching chamber, the hot flue gas in the pipeline has a higher chlorine content, and the coarse ash sent back to the calciner has a lower chlorine content, which has a much smaller impact on the kiln system than the traditional 350°C high-chlorine coarse ash.

5. The present invention conducts harmless disposal of excessive harmful components in the cement kiln system, and solves the phenomenon of crust blockage caused by the circulation and enrichment of harmful components in the system.

6. By controlling the liquid level of the cooling liquid in the quench chamber, the position of the external cleaning component can be controlled, so as to drive the external cleaning component to undulate, realize the cleaning of the outside of the heat exchange tube, and reduce the heat exchange effect caused by the adhesion of dirt A reduction occurs;

7. The heat exchange tubes can be separated into different liquid control spaces by configuring partitions. In this way, the liquid level height of the coolant in different spaces can be individually controlled, thereby ensuring that at least one liquid control space is filled with coolant, realizing real-time During the cooling process, the position adjustment of the external cleaning components is realized, thereby realizing real-time descaling.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of a new water-cooled bypass ventilation coupling SNCR system;

Fig. 2 is a structural schematic diagram of the quenching assembly in a novel water-cooled bypass ventilation coupling SNCR system;

FIG. 3 is a partially enlarged structural schematic diagram of FIG. 2;

Fig. 4 is a structural schematic diagram of a new type of water-cooled bypass ventilation coupling SNCR system with external cleaning components;

In the figure: 1. Calciner; 2. Flue gas chamber; 3. Flap flap valve; 4. Cyclone; 5. Temperature adjustment chamber; 6. SNCR ammonia injection device; 7. Quenching component; , exhaust fan; 10, kiln tail chimney; 11, scraper conveyor; 12, ash bin; 71, quenching warehouse; 72, air induction pipe; 73, heat exchange pipe; 74, liquid supply pipe; , clapboard; 77, collecting pipe; 78, soaking pipe group; 79, external cleaning assembly; 781, extension pipe; 782, soaking pipe; 783, bushing; 784, air inlet; ; 793, floating ball.

Detailed ways

Embodiment: Please refer to Fig. 1～4, in the embodiment of the present invention, a kind of novel water-cooled bypass ventilating coupling SNCR system is used for processing the flue gas in the flue gas chamber 2 of calciner 1, comprises ascending pipe, SNCR nozzle Ammonia device 6, cyclone 4, quenching component 7, dust collector 8 and exhaust fan 9, wherein the flue gas in the flue gas chamber 2 flows through the ascending pipe, cyclone 4, quenching component 7 and dust collector 8 in sequence;

The SNCR ammonia injection device 6 is arranged on the ascending pipeline;

The coarse ash in the flue gas separated by the cyclone 4 is sent back to the calciner 1, and then the fine dust is purified by the dust collector 8 and discharged into the chimney 10 at the end of the kiln through the exhaust fan 9.

That is to say, a certain proportion of high-temperature flue gas is extracted from the front of the flue gas chamber 2, and an SNCR ammonia injection device 6 is installed on the ascending pipe to denitrify the high-temperature flue gas, accompanied by a temperature regulating chamber 5 to control the temperature of the ascending pipe In the optimal reaction temperature range for denitrification; the hot flue gas first enters the cyclone 4 for coarse ash-fine ash separation, and the coarse ash with low chlorine content is sent back to the calciner 1. Specifically, the coarse ash is returned to To the calciner 1, a flap valve 3 is installed on the feeding pipeline; while the high-chlorine hot flue gas enters the water-cooled quenching component 7 for a sharp drop in temperature to 200°C, reaching the inlet temperature requirement of the dust collector 8, and is purified by the dust collector 8 After that, it is discharged into the kiln tail chimney 10 through the exhaust fan 9; and the dust collector 8 can intercept the fine ash, and the collected kiln ash is sent to the ash bin 12 through the scraper conveyor 11 for the next step of disposal.

As a preferred embodiment, the distance between the cyclone 4 and the flue gas chamber 2 is ≥20m, so as to ensure that the residence time of the flue gas in it is ≥2.5s;

The front end of the SNCR ammonia injection device 6 is provided with a temperature regulating chamber for keeping the temperature in the pipeline between 850°C and 920°C;

The reducing agent in the SNCR ammonia injection device is ammonia water with a concentration ≥ 20%, and the spray gun is an L-shaped two-fluid spray gun.

The quenching component is water-cooled, and can quench the high-temperature flue gas to 180°C-220°C within 2-4s.

As shown in Figure 1, a temperature adjustment chamber 5 is installed in front of the SNCR ammonia injection device to ensure that the reaction window is kept at 850°C-920°C, the amount of ammonia water injected into the system is controlled at 0.1-0.2m ³ /h, and the reaction residence time is kept at least 2.5 s, to achieve denitrification efficiency ≥ 70%. Using this embodiment, the Cl ^- content in the coarse ash is 1.6%, which is much lower than the 5-7% Cl ^- content in the coarse ash after the quenching chamber in the process flow of the traditional air-cooled bypass system; The cyclone is then cooled to 200°C by the quenching device, and the Cl ^- content in the fine ash is >20%, which reduces the air volume by 35% compared with the traditional air-cooled bypass system.

In this embodiment, as shown in Figures 2-4, the quenching assembly 7 includes a quenching chamber 71, an air induction pipe 72, a heat soaking tube group 78, and a heat exchange tube 73, wherein the quenching chamber 71 is embedded with a heat exchange tube 73, The inlet end of the heat exchange pipe 73 is connected with the air-introduction pipe 72 by means of a uniform heat pipe group 78. The heat-soak pipe group is located outside the quenching chamber 71, and the air induction pipe 72 is located in the interior of the rapid cooling chamber 71. The top of the rapid cooling chamber A spray pipe 75 is configured to spray coolant into the quench chamber 71. The spray pipe 75 is connected to an external liquid supply assembly using a liquid supply pipe 74. The bottom of the quench chamber 71 is also provided with a collector for discharging the coolant. Tube 77.

In this embodiment, the heat equalizing tube group 78 includes an extension tube 781, a heat equalizing tube 782, and a sleeve 783, wherein one end of the extension tube communicates with the air induction tube 781, and the other end is connected with the sleeve 783 by using a heat equalizing tube 782 connected, and the extension tube and the heat soaking tube 782 can jointly form a back-shaped tube body with a gap. The intake ports are connected.

In this embodiment, the heat exchange tubes 73 are arranged vertically, and the tops of the multiple heat exchange tubes 73 are all collected on the horizontal tube as the inlet end of the heat exchange tubes 73. The multiple heat exchange tubes 73 The bottom of each heat exchange tube 73 is slidingly sleeved with an outer cleaning assembly 79, and the bottom of each heat exchange tube 73 is connected to the exhaust pipe as the outlet end of the heat exchange tube 73. The outer cleaning assembly 79 is able to float on the coolant.

In addition, the outer cleaning assembly 79 includes a cleaning sleeve 791, the inner surface of the cleaning sleeve 791 has teeth, the outer surface of the cleaning sleeve is fixed with a floating ball 793, and the outer cleaning assembly 79 can be floated by the floating ball 793 On the cooling liquid, a plurality of through pipes 792 are embedded in the middle of the cleaning sleeve.

That is to say, the outer cleaning assembly 79 can be floated on the cooling liquid by the float 793, so that the position of the outer cleaning assembly 79 can be controlled by controlling the liquid level of the cooling liquid in the quench chamber, thereby driving the outer cleaning assembly 79 to perform Ups and downs, realize the cleaning of the outside of the heat exchange tube, and reduce the reduction of the heat exchange effect caused by the adhesion of dirt;

Moreover, during implementation, the number of heat exchange tubes 73 can be configured according to specific conditions;

In a preferred embodiment, only two heat exchange tubes 73 are configured.

In addition, the quench chamber 71 is also horizontally provided with a partition 76, through which the heat exchange tube 73 can be separated into two upper and lower liquid control spaces, and each liquid control space is connected to the collection pipe 77 by a liquid control tube. Above, the liquid control pipe is provided with a valve body, and the liquid control space below is also supplied with liquid by an external liquid supply assembly.

It should be explained that the heat exchange tubes 73 can be separated in different liquid control spaces by configuring the partition plate 76, so that the liquid level height of the cooling liquid in different spaces can be individually controlled, thereby ensuring that at least one liquid control space is filled with cooling water. Liquid, to realize the position adjustment of the outer cleaning component 79 during the real-time cooling process, and then realize real-time descaling.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technology of the present invention Any equivalent replacement or change of the scheme and its inventive concepts shall fall within the protection scope of the present invention.

Claims (10)

1. Novel water-cooled bypass air release coupling SNCR system for handle the flue gas in flue gas chamber (2) of decomposition stove (1), its characterized in that: the device comprises a rising pipeline, an SNCR ammonia spraying device (6), a cyclone cylinder (4), a quenching component (7), a dust collector (8) and an exhaust fan (9), wherein the flue gas in a flue gas chamber (2) sequentially flows through the rising pipeline, the cyclone cylinder (4), the quenching component (7) and the dust collector (8);

the SNCR ammonia spraying device (6) is arranged on the ascending pipeline;

coarse ash separated by the cyclone (4) in the flue gas is sent back to the decomposing furnace (1), and then purified by the dust collector (8) and discharged into a kiln tail chimney (10) by the exhaust fan (9).

2. The novel water-cooled bypass vent coupling SNCR system according to claim 1, wherein: the distance between the cyclone cylinder (4) and the smoke chamber (2) is more than or equal to 20m so as to ensure that the residence time of the smoke in the cyclone cylinder is more than or equal to 2.5s.

3. The novel water-cooled bypass vent coupling SNCR system according to claim 1, wherein: the front end of the SNCR ammonia spraying device (6) is provided with a temperature regulating chamber which is used for keeping the temperature in the pipeline between 850 ℃ and 920 ℃.

4. The novel water-cooled bypass vent coupling SNCR system according to claim 1, wherein: the reducing agent in the SNCR ammonia spraying device adopts ammonia water with the concentration of more than or equal to 20%, and the spray gun adopts an L-shaped double-fluid spray gun.

5. The novel water-cooled bypass vent coupling SNCR system according to claim 1, wherein: the quenching component is water-cooled and can quench the high-temperature flue gas to 180-220 ℃ within 2-4 seconds.

6. The novel water-cooled bypass vent coupling SNCR system according to claim 1, wherein: quenching subassembly (7) include quenching storehouse (71), bleed air pipe (72), soaking tube group (78) and heat exchange tube (73), wherein, embedded heat exchange tube (73) in quenching storehouse (71), the inlet end of heat exchange tube (73) adopts soaking tube group (78) to be linked together with bleed air pipe (72), soaking tube group is located the outside of quenching storehouse (71), bleed air pipe (72) are located the inside of quenching storehouse (71), the top of quenching storehouse is furnished with spray tube (75) for to spray the coolant liquid in quenching storehouse (71), spray tube (75) adopt liquid feed pipe (74) to link to each other with outside liquid feed subassembly, the bottom of quenching storehouse (71) still is provided with header (77) that are used for discharging the coolant liquid.

7. The novel water-cooled bypass vent coupling SNCR system as recited in claim 6, wherein: the soaking tube group (78) comprises an extension tube (781), a uniform heat tube (782) and a sleeve (783), wherein one end of the extension tube is communicated with the air guide tube (781), the other end of the extension tube is communicated with the sleeve (783) through the uniform heat tube (782), the extension tube and the uniform heat tube (782) can jointly form a reverse-shaped tube body with a notch, and part of the tube body of the sleeve (783) is sleeved on part of the tube body of the uniform heat tube and is communicated with the air inlet end of the heat exchange tube (73).

8. The novel water-cooled bypass vent coupling SNCR system as recited in claim 6, wherein: the heat exchange pipes (73) are vertically arranged, the tops of the heat exchange pipes (73) are all converged on a transverse pipe serving as an air inlet end of the heat exchange pipes (73), the bottoms of the heat exchange pipes (73) are all converged on an exhaust pipe serving as an air outlet end of the heat exchange pipes (73) through a quenching bin, and the exhaust pipe is communicated with the dust collector (8); the outer cleaning assemblies (79) are sleeved on the heat exchange tubes (73) in a sliding mode, and the outer cleaning assemblies (79) can float on cooling liquid.

9. The novel water-cooled bypass vent coupling SNCR system according to claim 8, wherein: the quenching bin (71) is also horizontally provided with a baffle plate (76), the heat exchange tube (73) can be separated into an upper liquid control space and a lower liquid control space through the baffle plate (76), each liquid control space is communicated to a collecting pipe (77) through a liquid control tube, the liquid control tube is provided with a valve body, and the liquid control space at the lower part is supplied with liquid by an external liquid supply assembly.

10. The novel water-cooled bypass vent coupling SNCR system according to claim 8, wherein: the outer cleaning component (79) comprises a cleaning sleeve (791), teeth are arranged on the inner surface of the cleaning sleeve (791), a floating ball (793) is fixed on the outer surface of the cleaning sleeve, the outer cleaning component (79) can float on cooling liquid through the floating ball (793), and a plurality of through pipes (792) are embedded in the middle of the cleaning sleeve in a penetrating mode.

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