CN212790495U - Flue gas purification system of industrial incinerator - Google Patents
Flue gas purification system of industrial incinerator Download PDFInfo
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- CN212790495U CN212790495U CN202021080238.7U CN202021080238U CN212790495U CN 212790495 U CN212790495 U CN 212790495U CN 202021080238 U CN202021080238 U CN 202021080238U CN 212790495 U CN212790495 U CN 212790495U
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Abstract
The utility model relates to a flue gas purification system of an industrial incinerator, which belongs to the technical field of industrial incineration flue gas treatment, and comprises a waste heat boiler, a primary dry method treatment unit, a quenching treatment unit and a secondary dry method treatment unit, wherein the high-temperature flue gas of the incinerator is cooled by the waste heat boiler and recovers heat, the flue gas is preliminarily purified by the primary dry method treatment unit, then the flue gas is cooled to be within 200 ℃ at the highest speed by the quenching treatment unit, thereby striding over the optimum temperature range of dioxin synthesis of 500-300 ℃, the dioxin is prevented from being synthesized again, meanwhile, the heat of the flue gas is recovered by byproduct saturated steam, finally, the flue gas is thoroughly purified by the secondary dry method treatment unit, and the heat is continuously recovered by an economizer, the high-altitude emission is completed under the action of an induced draft fan and a chimney, various problems caused by water spray quenching are effectively avoided, and the efficiency, no extra energy is consumed, and the heat generated in the flue gas purification process is recovered to the maximum extent.
Description
Technical Field
The utility model relates to an industry burns flue gas processing technology field, in particular to industry burns burning furnace's gas cleaning system.
Background
Dioxin is a highly toxic polychlorinated biphenyl compound, has strong carcinogenic and teratogenic effects, and can cause serious secondary pollution to air, soil and water. Dioxin is mainly derived from industrial smelting and industrial waste incineration, such as waste copper smelting, if the cooling mode is not properly selected, the cooling process of high-temperature flue gas (850 ℃) can be associated with dioxin, and the dioxin generated by waste incineration can be summarized into the following aspects:
(1) high-temperature gas-phase synthesis. Due to the adverse effects of low garbage heat value, unstable feeding, high-content chlorine source garbage (such as PVC and medical waste) doped into the feeding of an incinerator and the like, the garbage is not sufficiently combusted, the temperature of a hearth is low (lower than 850 ℃), the chlorine source garbage is decomposed at high temperature to generate a dioxin precursor, but the precursor cannot be completely decomposed, and the precursor is continuously polymerized to generate dioxin with larger molecules and more complex structures. If the garbage is mixed with a dioxin synthesis catalyst such as CuCl2 and FeCl3, a large amount of dioxin is generated.
(2) Low-temperature heterogeneous catalytic synthesis. If the high-temperature flue gas cannot be quenched, chlorinated aromatic compounds such as chlorobenzene, chlorophenol or polychlorinated biphenyl (chemical structures are similar to those of dioxin) which are difficult to pyrolyze in the garbage can be polymerized with unburned carbon residues in the flue gas to generate dioxin when the flue gas is cooled to 500-300 ℃, and particularly, when the flue gas contains transition metal chloride catalysts such as CuCl2 and FeCl3, the probability of generating the dioxin again is greatly increased.
Referring to fig. 1, a flue gas treatment process of a conventional industrial refuse incinerator is shown, wherein high-temperature flue gas is firstly cooled to 550 ℃ by a waste heat boiler and then rapidly cooled to 200 ℃ by a spray quenching tower, but spray quenching cannot utilize flue gas waste heat, and a large amount of spray water is consumed. The more serious problem is that fly ash in the flue gas is easy to agglomerate, a quench tower is easy to corrode, scaling and blocking are easy to cause by water spraying and quenching, and the flue gas emission is influenced.
For garbage feeding with high nitrogen content or an incinerator with burning temperature of 1100 ℃ to ensure decomposition of dioxin, SNCR is configured in a waste heat boiler for flue gas purification, and low-temperature SCR catalytic denitration is configured behind a bag-type dust collector. However, in view of the requirement of the reaction activity of the SCR low-temperature catalyst, the flue gas needs to be heated to about 250 ℃ to enter the SCR for effective reaction, which consumes additional fuel gas and increases the operation cost of the hazardous waste incinerator.
In addition, for a garbage incinerator with high halogen content or sulfur content, a primary dry deacidification (semi-dry tower) and an alkali liquor wet washing tower are required to be arranged for conventional flue gas purification, so that the emission of acid gas in the flue gas is qualified. This inevitably introduces industrial waste water which is difficult to treat, which is another disadvantage of the flue gas purification of the conventional industrial incinerator.
Aiming at the problem that the flue gas of the conventional industrial incinerator can not be quenched and the waste heat can not be utilized, follow-up industrial incinerator manufacturers and related enterprises also provide a plurality of methods for quenching the flue gas and utilizing the waste heat:
chinese patent CN110433643A discloses a high-efficiency energy-saving environment-friendly quench tower, wherein high-temperature flue gas enters the bottom of the quench tower through the lateral direction of a venturi tube and then flows upwards through a section of waste heat recovery tower, and the outer wall of the waste heat recovery tower is provided with a waste heat recovery tube bundle for recovering a part of flue gas waste heat, but the top of the waste heat recovery tower is still provided with a quench spray header.
However, it is obvious that high-temperature flue gas passes through the cavity of the waste heat recovery tower, the limited outer wall tube bundle cannot economically and effectively recover flue gas waste heat, and then spray water droplets on the top of the quenching tower inevitably adhere to fly ash at the bottom of the tower, so that the fly ash is difficult to discharge outside, and the operation of equipment is influenced. Thus, the patent is not much different from a conventional spray quench tower.
Chinese patent CN108006686A discloses a quenching exhaust-heat boiler, which comprises a flue gas inlet pipe, a combustion settling chamber, a quenching heat exchanger and a flue gas outlet pipe which are sequentially connected along the flue gas flow direction, wherein the quenching heat exchanger is vertically communicated with the top of the combustion settling chamber, the flue gas inlet pipe is arranged at the same side of the combustion settling chamber and the quenching heat exchanger, and the quenching heat exchanger is provided with at least one laval nozzle for uniformly distributing flue gas at the bottom communicated with the combustion settling chamber.
Similar to chinese patent CN110433643A, the actual high temperature flue gas flows through the cavity cylinder without heat exchange tubes, only the outer wall of the cylinder is provided with the cooling water pipe which is inclined upwards, the cooling water pipe does not generate steam, the waste heat of the high temperature flue gas is difficult to be effectively utilized, and the quenching effect is difficult to be ensured.
Referring to fig. 2, a flue gas quenching and cooling device for inhibiting generation of dioxin by using a heat pipe heat exchanger is introduced in 5 th (total 416 th) of 2017, namely, energy conservation in the industrial journal. The test shows that the time for cooling the flue gas of the heat pipe heat exchanger from 600 ℃ to 200 ℃ is 1.35 s. However, the heat pipe heat exchanger is limited to an arrangement mode that a cooling medium flows through the pipe and high-temperature flue gas flows through the pipe, the heat transfer coefficient of the high-temperature flue gas side is low, and even if the finned pipe is adopted, the effect is not greatly increased, so that the heat pipe heat exchanger is very unfavorable for quenching and cooling the flue gas to inhibit the generation of dioxin.
Referring to fig. 3, chinese patent CN102492456B discloses a quench heat exchanger for an ethylene cracking furnace, in which high temperature cracked gas passes through a tube side, a shell of the heat exchanger is divided into two shell sides (13 and 14 in fig. 3) by a tube plate, the first shell side passes through high pressure boiler water to generate high pressure steam, and the second shell side passes through boiler water supplement.
However, the arrangement mode of the two sections of shells and the one bundle of tubes of the quenching heat exchanger does not consider the volume shrinkage problem caused by quenching and cooling of the pyrolysis gas, the flow velocity difference of the pyrolysis gas in the two sections of tubes is very large, and the necessary flow velocity of the pyrolysis gas in the second section of shell tube bundle is difficult to ensure, so that the heat transfer coefficient of the gas side in the second section of shell and the necessary quenching efficiency are difficult to ensure.
Therefore, the above improved method does not actually solve the contradiction between rapid flue gas quenching to jump the sensitive generation temperature zone of dioxin and taking into account the higher heat transfer coefficient and the necessary heat transfer area on the required flue gas side to achieve waste heat recovery.
In addition, there are two problems with the purification of flue gas from conventional industrial incinerators: the low-temperature SCR is arranged behind the bag-type dust collector, and the flue gas can be heated to the temperature required by the SCR catalytic reaction only by carrying out additional fuel gas heating or steam heating; and secondly, a large amount of discharged wastewater is generated by primary dry deacidification (semi-dry tower) and alkaline liquor wet deacidification, fine powder and heavy metal chloride which adsorb dioxin and the like can be dissolved in the wastewater, and compared with a small amount of fine powder which only adsorbs the dioxin and the heavy metal chloride, the wastewater is more difficult to treat.
SUMMERY OF THE UTILITY MODEL
In order to overcome prior art's defect, the utility model provides an industrial flue gas purification system who burns burning furnace, high temperature flue gas that burns burning furnace passes through exhaust-heat boiler cooling to within 560 ℃ after, purifies the flue gas through one-level dry processing unit, rapid cooling processing unit and second grade dry processing unit, not only effectively restricts the synthesis of dioxin, has still improved the efficiency of flue gas catalytic denitration, effectively retrieves heat energy simultaneously, environmental protection more.
The technical scheme for realizing the purpose is as follows:
the utility model provides a flue gas purification system of an industrial incinerator, which comprises a waste heat boiler, a primary dry processing unit, a quenching processing unit and a secondary dry processing unit, wherein the high-temperature flue gas of the incinerator is cooled to be within 560 ℃ through the waste heat boiler, and the heat is recovered;
the primary dry processing unit comprises a primary dry deacidification mixer, a primary dry deduster and a medium-high temperature SCR reactor which are sequentially connected, and is used for removing dust which is possibly adsorbed with heavy metals in the flue gas cooled to be within 560 ℃, excessively spraying a dry deacidification agent and reducing NOx in the flue gas, and the flue gas is cooled to 550 ℃ along with the dust, the flue gas heater required by the conventional low-temperature SCR reactor is saved, the catalytic denitration efficiency of the flue gas is improved, and no extra energy is consumed;
the quenching treatment unit comprises a quenching boiler for rapidly quenching to reduce the temperature of the flue gas to 200 ℃ and avoid the re-synthesis of dioxin, wherein the quenching boiler is an upper section and a lower section integrated tubular heat exchanger and comprises an upper section heat exchanger, a lower section heat exchanger and a connecting cylinder body for communicating the upper section heat exchanger and the lower section heat exchanger;
the secondary dry processing unit comprises a secondary dry deacidification reactor and a secondary dry deduster which are sequentially connected, the lower reaches of the secondary dry deduster are sequentially connected with an economizer, an induced draft fan and a chimney, the flue gas is further purified and the heat is recovered, and then the flue gas is discharged to the high altitude through the induced draft fan and the chimney, wherein the economizer, the quenching boiler and the waste heat boiler form a complete flue gas waste heat recovery system.
Further, the primary dry deacidification mixer is a pipeline mixer, and the deacidification agent in the primary dry deacidification mixer is CaO dry powder or Ca (OH)2And (3) slurry.
Further, the first-stage dry dust collector is a ceramic filter or a cyclone separator and is used for separating dust with heavy metal adsorbed in the flue gas and excessive deacidification agent.
Furthermore, an upper end enclosure is arranged at one end, far away from the connecting cylinder, of the upper section heat exchanger, the upper end enclosure is provided with a flue gas inlet, the upper section heat exchanger comprises an upper cylinder and upper pipe plates fixedly arranged at two ends of the upper cylinder, an upper heat exchanger pipe bundle communicated with the upper end enclosure and the connecting cylinder is arranged between the upper pipe plates at the two ends, the upper heat exchanger pipe bundle is composed of a plurality of upper heat exchange pipes which are uniformly distributed, and the upper cylinder is provided with a saturated boiler water inlet and a saturated steam and boiler water outlet;
a lower end socket is arranged at one end of the lower section heat exchanger, which is far away from the connecting cylinder body, a flue gas outlet is formed in the lower end socket, the lower section heat exchanger comprises a lower cylinder body and lower tube plates fixedly arranged at two ends of the lower cylinder body, a lower heat exchanger tube bundle communicated with the connecting cylinder body and the lower end socket is arranged between the lower tube plates at the two ends, the lower heat exchanger tube bundle is composed of a plurality of lower heat exchange tubes which are uniformly distributed, the number of the lower heat exchange tubes is smaller than that of the upper heat exchange tubes, and the lower cylinder body is provided with a boiler water supplementing inlet and a preheated boiler water supplementing;
the flue gas enters the connecting cylinder body through the upper heat exchange tube by the flue gas inlet pipe pass, the flue gas flows out of the flue gas outlet by the lower heat exchange tube after being redistributed in the connecting cylinder body, and the saturated boiler water and the supplementary boiler water respectively flow through the shell passes of the upper section heat exchanger and the lower section heat exchanger to finish the rapid cooling of the flue gas, generate saturated steam and recover heat.
Further, go up the heat exchange tube with the pipe diameter of heat exchange tube is the same down, conveniently goes up the preparation or the purchase of heat exchange tube and lower heat exchange tube, go up the heat exchange tube with the quantity ratio of heat exchange tube is 1.2 ~ 1.8 down: 1, after the flue gas passes through the upper section heat exchanger for quenching, the flue gas can keep higher flow velocity in the lower heat exchange tube of the lower section heat exchanger, so that the overall time for quenching the flue gas is shortened.
Further, the top of going up heat exchange tube and heat exchange tube down all the endotheca has wear-resisting sleeve pipe for heat exchange tube and lower heat exchange tube in the protection, improve its life, just go up the heat exchange tube and all inlayed in the heat exchange tube down and have interior fin or baffling piece, be used for strengthening the coefficient of heat transfer of intraductal flue gas side.
Furthermore, the upper tube plate is a flexible tube plate, refractory castable is poured on one side, close to the flue gas inlet, of the upper tube plate close to the upper end enclosure, and the lower tube plate is a flexible tube plate or a fixed tube plate.
Further, the sum of the thicknesses of the upper tube plate and the refractory castable is 10-40 mm, and preferably 20-30 mm.
Further, the secondary dry deacidification reactor is a semi-dry tower, the secondary dry deduster is a bag-type deduster, activated carbon and powdered baking soda or slaked lime are sprayed on the semi-dry tower, a possible small amount of dioxin in the flue gas is adsorbed by the activated carbon, acid gas in the flue gas is further removed by the powdered baking soda or slaked lime, and the excessive baking soda or slaked lime and the activated carbon adsorbed with the dioxin in the semi-dry tower are filtered and intercepted by the bag-type deduster.
The application also provides a flue gas purification method using the flue gas purification system, which comprises the following steps:
s1, cooling the high-temperature flue gas of the industrial incinerator to below 560 ℃ through a waste heat boiler, and recovering heat;
s2, sequentially passing the cooled flue gas through a primary dry deacidification mixer, a primary dry deduster and a medium-high temperature SCR reactor to remove dust which may adsorb heavy metals in the flue gas, an excessively sprayed dry deacidification agent and reduce NOx in the flue gas;
s3, cooling the flue gas to be within 200 ℃ within 1 second through a quenching boiler, and simultaneously by-producing 0.5-2.0 MPaG saturated steam to recover the heat of the flue gas;
s4, further purifying the flue gas by the secondary dry deacidification reactor, the secondary dry deduster and the economizer after the temperature of the flue gas is reduced again, and preheating the boiler for water supplement;
and S5, discharging the purified flue gas to the high altitude through a draught fan and a chimney.
Further, in step S3, the flow velocity of the flue gas in the upper section heat exchanger and the lower section heat exchanger of the quenching boiler is controlled to be 10-20 m/S, so that the flue gas can be rapidly quenched (less than 1.0S), the same effect as spray quenching is achieved, and the problems of equipment scaling, corrosion and the like caused by spray quenching are avoided.
Has the advantages that: compared with the prior art, the utility model has the difference that the utility model provides a flue gas purification system of industrial incinerator, including exhaust-heat boiler, one-level dry processing unit, rapid cooling processing unit and second grade dry processing unit, the high temperature flue gas of incinerator passes through exhaust-heat boiler cooling and retrieves the heat, and through the flue gas of one-level dry processing unit preliminary purification, reduce the probability that dioxin produced, the possible dioxin precursor in the high temperature SCR reactor part catalytic decomposition flue gas, then make the flue gas extremely fast cool down to within 200 ℃ through rapid cooling processing unit, thereby stride over the most suitable temperature interval of dioxin synthesis 500 ~ 300 ℃, avoid the resynthesis of dioxin, the heat of flue gas is retrieved to the by-product saturated steam at the same time, purify the flue gas thoroughly through second grade dry processing unit at last, and continue to retrieve the heat through the economizer, accomplish the high altitude under the effect of draught fan and chimney and discharge, the flue gas purification system of the industrial incinerator and the purification method thereof effectively avoid various problems caused by water spray quenching, improve the efficiency of flue gas catalytic denitration by arranging the medium-high temperature SCR reactor before quenching, do not consume extra energy, form a complete flue gas waste heat recovery system by the waste heat boiler, the quenching treatment unit and the economizer, recover the heat generated in the flue gas purification process to the maximum extent, reduce the operation cost of flue gas purification, and are a green and energy-saving flue gas purification technology.
Drawings
FIG. 1 is a flow chart of the flue gas treatment of a conventional industrial garbage incinerator of the prior art.
Fig. 2 is a schematic diagram of a quenching cooling device for cooling flue gas and inhibiting dioxin in the prior art.
FIG. 3 is a schematic structural diagram of a quench heat exchanger for an ethylene cracking furnace according to the prior art.
FIG. 4 is a flow chart of a flue gas purification system of an industrial incinerator according to a preferred embodiment of the present application.
Fig. 5 is a schematic structural view of a quench boiler in the present application.
FIG. 6 is a schematic diagram of the distribution of the upper heat exchanger tube bundles in the quench boiler of the present application.
Fig. 7 is a schematic view of the distribution of the upper heat exchange tubes in the present application.
Fig. 8 is a schematic view of the distribution of the lower heat exchange tubes in the present application.
Wherein, 1-a waste heat boiler, 2-a primary dry deacidification mixer, 3-a primary dry deduster, 4-a medium-high temperature SCR reactor, 5-a quench boiler, 11-an upper section heat exchanger, 111-an upper end enclosure, 112-a flue gas inlet, 113-an upper barrel, 114-an upper tube plate, 115-an upper heat exchanger tube bundle, 116-an upper heat exchange tube, 117-a saturated boiler water inlet, 118-a saturated steam and boiler water outlet, 12-a connecting barrel, 13-a lower section heat exchanger, 131-a lower end enclosure, 132-a flue gas outlet, 133-a lower barrel, 134-a lower tube plate, 135-a lower heat exchanger tube bundle, 136-a lower heat exchange tube, 137-a boiler water replenishing inlet, 138-a preheated boiler water replenishing outlet, 14-refractory castable and 6-a semi-dry tower, 7-a bag-type dust collector, 8-a coal economizer, 9-an induced draft fan and 10-a chimney.
Detailed Description
The invention will be further explained with reference to the drawings and the specific embodiments.
Referring to fig. 4 and 5, the utility model provides a flue gas purification system of an industrial incinerator, which comprises a waste heat boiler 1, a primary dry processing unit, a quenching processing unit and a secondary dry processing unit, wherein the primary dry processing unit, the quenching processing unit and the secondary dry processing unit are sequentially processed at the downstream of the waste heat boiler 1;
after industrial waste DMF residues, sludge, waste resin, ground leather powder, waste activated carbon and desorption condensation waste liquid are mixed, the mixture is fed to a test rotary kiln incinerator and a second combustion chamber through a screw feeder, and the combustion air quantity of the test rotary kiln and the second combustion chamber is 840Nm3/hr；
Wherein, the following chart 1 is the feed amount and composition of the test solid waste and hazardous waste:
| DMF residue | Buffing powder | Sludge for sewage treatment | Waste resin | Waste activated carbon | Desorption condensate | |
| Mass flow rate, kg/hr | 17.50 | 41.70 | 4.20 | 7.80 | 0.30 | 10.00 |
| Heat, KW | ～124.00 | ～330.00 | ～10.00 | ～55.00 | 0.00 | ～15.00 |
| LHV,kcal/kg | 6,090.00 | 6,831.00 | 1,760.00 | 6,010.00 | 6,831.00 | 2,663.00 |
| Received base | Received base | Received base | Received base | Received base | Received base | |
| All water | 14.30 | 6.00 | 60.30 | 16.70 | 20.00 | 80.00 |
| Ash content A | 5.50 | 1.50 | 11.60 | 10.00 | 0.00 | 0.00 |
| Carbon C | 53.70 | 59.50 | 14.00 | 54.00 | 53.70 | 15.00 |
| Hydrogen H | 7.10 | 8.30 | 3.00 | 6.40 | 9.00 | 5.00 |
| Oxygen O | 12.80 | 16.40 | 8.00 | 9.50 | 5.90 | 0.00 |
| N-N | 6.40 | 8.30 | 2.20 | 3.20 | 11.20 | 0.00 |
| Sulfur S | 0.10 | 0.00 | 0.80 | 0.10 | 0.10 | 0.00 |
| Chlorine Cl | 0.10 | 0.00 | 0.10 | 0.10 | 0.10 | 0.00 |
Cooling the high-temperature flue gas of the incinerator to be within 560 ℃ through the waste heat boiler 1, and recovering heat;
the primary dry processing unit comprises a primary dry deacidification mixer 2, a primary dry deduster 3 and a medium-high temperature SCR reactor 4 which are sequentially connected, wherein
The primary dry deacidification mixer 2 is a pipe mixer with or without mixing elements, preferably without mixing elements, and the deacidification agent is CaO dry powder or Ca (OH)2The slurry, preferably CaO dry powder, is pneumatically conveyed and sprayed into 0.5kg/hr of CaO dry powder of quick lime with carrier gas of 3.0barg and 5Nm3The grain diameter of CaO dry powder is 50 μm by the compressed air per hr, the nozzle is inserted into the center of the mixing pipe, and the spraying direction is consistent with the flow direction of the flue gas;
the first-stage dry dust collector 3 is a ceramic filter or a cyclone separator, preferably a ceramic filter, the filtering precision of the ceramic filter is 10 μm, the windward speed is 1.0m/min, and the filtering area is 50m2The dust removal efficiency is 95 percent, and the fly ash at the cone bottom is 2.7 kg/hr;
NH is sprayed into the medium-high temperature SCR reactor 43-H2O is 3.85kg/hr (30 wt% aqueous ammonia), and the injection carrier gas is 3.0barg and 10Nm3In the/hr compressed air, the catalyst is an iron-based molecular sieve, TiO2, V2O5 and WO3 are used as main active components, the catalytic reaction temperature is 300-550 ℃, the catalyst also has a catalytic decomposition effect on chlorobenzene and chlorophenol dioxin precursors, compared with a low-temperature SCR reactor, the medium-high temperature SCR reactor 4 has higher denitration efficiency, and smoke gas does not need to consume extra gas combustion or steam heating, so that energy and operation cost are saved;
table 2 shows the flue gas amount and composition of the second combustion chamber outlet, the exhaust-heat boiler outlet, the flue gas inlet, the flue gas outlet and the economizer outlet of the test rotary kiln:
the rapid cooling treatment unit comprises a rapid cooling boiler 5 for rapidly cooling the flue gas to 200 ℃ to avoid the re-synthesis of dioxin, the rapid cooling boiler 5 is an upper section and a lower section of integrated tubular heat exchanger and comprises an upper section of heat exchanger 11, a lower section of heat exchanger 13 and a connecting cylinder 12 for communicating the upper section of heat exchanger 11 and the lower section of heat exchanger 13, the upper section of heat exchanger 11 is used as a fire tube type tubular evaporator, and the lower section of heat exchanger 13 is used as a fire tube type tubular economizer;
the secondary dry processing unit comprises a secondary dry deacidification reactor and a secondary dry deduster which are sequentially connected, wherein the secondary dry deacidification reactor is preferably a half-dry tower 6, the secondary dry deduster is preferably a bag-type deduster 7, the half-dry tower 6 is sprayed with activated carbon and powdered baking soda or slaked lime, possible small amount of dioxin in the flue gas is adsorbed by the activated carbon, acid gas in the flue gas is further removed by the powdered baking soda or slaked lime, and the excessive baking soda or slaked lime in the half-dry tower 6 and the activated carbon adsorbed with the dioxin are filtered and intercepted by the bag-type deduster 7;
the lower stream of the secondary dry-method dust collector is sequentially connected with an economizer 8, an induced draft fan 9 and a chimney 10, the flue gas is discharged to the high altitude through the induced draft fan 9 and the chimney 10 after being further purified and the heat is recovered, wherein the economizer 8, the quenching boiler 5 and the waste heat boiler 1 form a complete flue gas waste heat recovery system, the economizer 8 can provide saturated boiler water for a steam pocket of the waste heat boiler 1 and can also provide boiler water for a lower-section heat exchanger 13 of the quenching boiler 5;
table 3 shows the process conditions for testing the waste heat recovery system of the present application:
as can be seen from Table 3, the waste heat recovered by the quenching boiler 5 is equivalent to 57.5% of the heat recovered by the conventional waste heat boiler, which is of great significance for the whole flue gas waste heat recovery.
As a preferred embodiment of the present application, an upper end enclosure 111 is disposed at one end of the upper heat exchanger 11 away from the connection cylinder 12, the upper end enclosure 111 is provided with a flue gas inlet 112, the upper section heat exchanger 11 comprises an upper cylinder 113 and upper tube plates 114 fixedly arranged at two ends of the upper cylinder 113, and an upper heat exchanger tube bundle 115 communicating the upper end enclosure 111 and the connecting cylinder 12 is vertically arranged between the upper tube plates 114 at the two ends, the upper heat exchanger tube bundle 115 consists of a plurality of upper heat exchange tubes 116 which are uniformly distributed, the upper cylinder 113 is provided with a saturated boiler water inlet 117 and a saturated steam and boiler water outlet 118, saturated boiler water required by the saturated boiler water inlet 117 can be supplemented by a steam drum at the top of the waste heat boiler 1, saturated boiler water produced by the saturated boiler water outlet 118 can flow back to the steam drum, and the saturated steam outlet is used for recovering smoke heat;
a lower end socket 131 is arranged at one end of the lower section heat exchanger 13 far away from the connecting cylinder 12, a flue gas outlet 132 is arranged on the lower end socket 131, the lower section heat exchanger 13 comprises a lower cylinder 133 and lower tube plates 134 fixedly arranged at two ends of the lower cylinder 133, a lower heat exchanger tube bundle 135 communicated with the connecting cylinder 12 and the lower end socket 131 is arranged between the lower tube plates 134 at the two ends, the lower heat exchanger tube bundle 135 consists of a plurality of lower heat exchange tubes 136 which are uniformly distributed, the number of the lower heat exchange tubes 136 is smaller than that of the upper heat exchange tubes 116, a boiler water supplementing inlet 137 and a preheated boiler water supplementing outlet 138 are arranged on the lower cylinder 133, boiler water required by the boiler water supplementing inlet 137 can be supplemented through an economizer 8, and boiler water produced by the preheated boiler water supplementing outlet 138 can be supplemented to a steam pocket;
the diameter of the upper cylinder 113 on the upper section heat exchanger 11 and the diameter of the lower cylinder 131 on the lower section heat exchanger 13 depend on the number of the respective tube bundles and the requirement of tube arrangement, and the diameters of the respective cylinders are different, preferably, the diameters of the respective cylinders are reduced into an integral and sectional shell, so as to adapt to the volume flow of the flue gas during cooling contraction, but the average flow velocity of the flue gas in the upper and lower sections of heat exchanger tubes is kept unchanged, specifically: the inner diameter of the upper cylinder 113 is 440mm, the outer diameter is 450mm, the cylinder length is 3358mm, and the average flow velocity of the flue gas in the cylinder is 15m/s, so that the temperature of the flue gas is rapidly cooled from 550 ℃ to 320 ℃ in the process that the flue gas passes through the upper section heat exchanger 11, and the quenching time is 0.22 s; the inner diameter of the lower cylinder 133 is 360mm, the outer diameter is 370mm, the cylinder length is 2440mm, and the average flow velocity of the flue gas in the cylinder is 16m/s, so that the flue gas temperature is quenched from 320 ℃ to 200 ℃ in the process of passing through the lower section heat exchanger 13, the quenching time is 0.15s, in addition, the length of the connecting cylinder 12 is 1000mm, the time for the flue gas to pass through is only 0.07s, and in sum, the flue gas passing time of the test quenching boiler 5 is only 0.22+0.15+ 0.07-0.44 s, which is far less than 1.0s, and the flue gas is quenched from 550 ℃ to 200 ℃, so that the flue gas quenching requirement of the industrial incinerator is completely met, the quenching boiler 5 replaces a conventional spray quenching tower, and the problems of scaling, corrosion and the like of equipment of conventional spray quenching are solved at the same.
The number of the upper heat exchange tubes 116 in the upper heat exchanger tube bundle 115 and the number of the lower heat exchange tubes 136 in the lower heat exchanger tube bundle 135 respectively depend on the flow velocity of flue gas in respective fire tubes and the respective heat exchange areas, as shown in fig. 5 to 8, the number ratio of the upper heat exchange tubes 116 to the lower heat exchange tubes 136 is 1.2-1.8: 1, an upper heat exchanger tube bundle 115 consists of 57 upper heat exchange tubes 116, a lower heat exchanger tube bundle 135 consists of 40 lower heat exchange tubes 136, the diameters of the upper heat exchange tubes 116 and the lower heat exchange tubes 136 are 38mm, the central distance between the tubes is 47mm, the heat exchange tubes are convenient to manufacture or purchase, the cost is saved, the heat exchange tubes are distributed in a regular triangle shape or in a quadrilateral or rhombic shape, and the specific limitation is not limited;
the flue gas enters the connecting cylinder 12 through the upper heat exchange tube 116 from the flue gas inlet 112, and after redistribution in the connecting cylinder 12, the flue gas flows out from the flue gas outlet 132 through the lower heat exchange tube 136, and the saturated boiler water and the supplementary boiler water respectively flow through the shell passes of the upper heat exchanger 11 and the lower heat exchanger 13, so that the flue gas is quenched, saturated steam is generated, and heat is recovered.
Preferably, wear-resistant sleeves are sleeved at the top ends of the upper heat exchange tube 116 and the lower heat exchange tube 136 respectively, so as to protect the upper heat exchange tube 116 and the lower heat exchange tube 136 and prolong the service life of the upper heat exchange tube 116 and the lower heat exchange tube 136, and internal fins or baffling fins are embedded in the upper heat exchange tube 116 and the lower heat exchange tube 136 respectively and used for enhancing the heat transfer coefficient of the smoke side in the tubes.
Preferably, the upper tube plate 114 is a flexible tube plate, and the side of the upper tube plate 114 at the upper end close to the flue gas inlet 112 is cast with refractory castable 14, and the lower tube plate 134 is a flexible tube plate or a fixed tube plate, more preferably a fixed tube plate.
Preferably, the sum of the thicknesses of the upper tube plate 114 and the refractory castable 14 is 10-40 mm, and preferably 20-30 mm.
The application also provides a flue gas purification method using the flue gas purification system, which comprises the following steps:
s1, cooling the high-temperature flue gas of the industrial incinerator to below 560 ℃ through a waste heat boiler, and recovering heat;
s2, sequentially passing the cooled flue gas through a primary dry deacidification mixer, a primary dry deduster and a medium-high temperature SCR reactor to remove dust which may adsorb heavy metals in the flue gas, an excessively sprayed dry deacidification agent and reduce NOx in the flue gas;
s3, cooling the flue gas to be within 200 ℃ within 1 second through a quenching boiler, and simultaneously by-producing 0.5-2.0 MPaG saturated steam to recover the heat of the flue gas;
s4, further purifying the flue gas by the secondary dry deacidification reactor, the secondary dry deduster and the economizer after the temperature of the flue gas is reduced again, and preheating the boiler for water supplement;
and S5, discharging the purified flue gas to the high altitude through a draught fan and a chimney.
Preferably, in step S3, the flow velocity of the flue gas in the upper heat exchanger and the lower heat exchanger of the quenching boiler is controlled to be 10-20 m/S, so that the flue gas can be rapidly quenched (< 1.0S), the same effect as spray quenching is achieved, and the problems of equipment scaling, corrosion and the like caused by spray quenching are avoided.
The above embodiments are merely preferred embodiments of the present disclosure, which are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like, which are within the spirit and principle of the present disclosure, should be included in the scope of the present disclosure.
Claims (10)
1. A flue gas purification system of an industrial incinerator comprises a waste heat boiler, and is characterized by further comprising a primary dry processing unit, a quenching processing unit and a secondary dry processing unit which are positioned at the downstream of the waste heat boiler and sequentially processed;
the primary dry processing unit comprises a primary dry deacidification mixer, a primary dry deduster and a medium-high temperature SCR reactor which are sequentially connected;
the quenching treatment unit comprises a quenching boiler, wherein the quenching boiler is an upper section and a lower section of integrated tubular heat exchanger and comprises an upper section heat exchanger, a lower section heat exchanger and a connecting cylinder body communicated with the upper section heat exchanger and the lower section heat exchanger;
the secondary dry processing unit comprises a secondary dry deacidification reactor and a secondary dry deduster which are sequentially connected, and the downstream of the secondary dry deduster is sequentially connected with an economizer, an induced draft fan and a chimney.
2. The flue gas purification system of an industrial incinerator according to claim 1, wherein said primary dry deacidification mixer is a pipeline mixer, and said deacidification agent in said primary dry deacidification mixer is CaO dry powder or Ca (OH)2And (3) slurry.
3. The flue gas cleaning system of an industrial incinerator according to claim 1 or 2 wherein said primary dry dust collector is a ceramic filter or cyclone.
4. The flue gas purification system of an industrial incinerator according to claim 1, wherein an upper head is arranged at one end of the upper section heat exchanger away from the connecting cylinder, the upper head is provided with a flue gas inlet, the upper section heat exchanger comprises an upper cylinder and upper tube plates which are hermetically arranged at two ends of the upper cylinder, an upper heat exchanger tube bundle which is communicated with the upper head and the connecting cylinder is arranged between the upper tube plates at the two ends, the upper heat exchanger tube bundle is composed of a plurality of upper heat exchange tubes which are uniformly distributed, and the upper cylinder is provided with a saturated boiler water inlet and a saturated steam and boiler water outlet;
the lower section heat exchanger is far away from the one end of connecting the barrel is equipped with the low head, the low head is equipped with exhanst gas outlet, the lower section heat exchanger includes down the barrel and seals to be located the low tube sheet at barrel both ends down, and be equipped with the intercommunication between the low tube sheet at both ends connect the barrel with the lower heat exchanger tube bank of low head, heat exchanger tube bank comprises many evenly distributed's lower heat exchange tube down, the quantity of heat exchange tube is less than down the quantity of going up the heat exchange tube, the barrel is equipped with boiler moisturizing import and preheats back boiler moisturizing export down.
5. A flue gas purification system of an industrial incinerator according to claim 4, wherein the upper heat exchange tubes and the lower heat exchange tubes have the same tube diameter, and the number ratio of the upper heat exchange tubes to the lower heat exchange tubes is 1.2-1.8: 1.
6. a flue gas purification system of an industrial incinerator according to claim 4 or 5, wherein wear resistant sleeves are sleeved in the top ends of the upper and lower heat exchange tubes, and internal fins or baffle plates are embedded in the upper and lower heat exchange tubes.
7. A flue gas purification system of an industrial incinerator according to claim 4 or 5 wherein said upper tube sheet is a flexible tube sheet and the side of said upper tube sheet adjacent to said upper head adjacent to said flue gas inlet is cast with refractory castable and said lower tube sheet is a flexible tube sheet or a fixed tube sheet.
8. The flue gas purification system of an industrial incinerator according to claim 7, wherein the sum of the thicknesses of said upper tube plate and said castable refractory is 10 to 40 mm.
9. The flue gas purification system of an industrial incinerator according to claim 8, wherein the sum of the thicknesses of said upper tube plate and said castable refractory is 20 to 30 mm.
10. The flue gas purification system of an industrial incinerator according to claim 1, characterized in that said secondary dry deacidification reactor is a semi-dry tower, said secondary dry deduster is a bag deduster, and said semi-dry tower is sprayed with activated carbon and powdered baking soda or slaked lime.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113230880A (en) * | 2021-04-28 | 2021-08-10 | 江西浣星谷科技有限公司 | Organic volatile gases (VOCs) treatment equipment and operation method thereof |
| CN113441028A (en) * | 2021-06-16 | 2021-09-28 | 南方科技大学 | Dioxin retardant injection device, hazardous waste treatment system and method |
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2020
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113230880A (en) * | 2021-04-28 | 2021-08-10 | 江西浣星谷科技有限公司 | Organic volatile gases (VOCs) treatment equipment and operation method thereof |
| CN113230880B (en) * | 2021-04-28 | 2024-05-14 | 江西浣星谷科技有限公司 | Organic volatile gas (VOCs) treatment equipment and operation method thereof |
| CN113441028A (en) * | 2021-06-16 | 2021-09-28 | 南方科技大学 | Dioxin retardant injection device, hazardous waste treatment system and method |
| CN113441028B (en) * | 2021-06-16 | 2023-09-26 | 南方科技大学 | Dioxin retarder injection device, hazardous waste treatment system and hazardous waste treatment method |
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