In-furnace and post-furnace alkali injection desulfurization device for waste fluidized bed incinerator

Abstract

The utility model relates to a kind of waste fluidized bed incinerator's in-furnace and furnace rear alkali solution desulfurization device including upper cylinder section, lower conical section and reducing diameter cylinder section successively connected to form an integrated body, air cap is equipped in the body in the junction of lower conical section and reducing diameter cylinder section, there is a primary air input pipeline in the side of reducing diameter cylinder section, to form primary air wind chamber in the body of reducing diameter cylinder section, form combustion chamber dense phase zone in the body of conical section and above it;The circumference of the upper cylinder section is densely covered with secondary air inlet, to form combustion chamber dilute phase zone in the body of upper cylinder section and above secondary air inlet;The waste fluidized bed incinerator's in-furnace and furnace rear alkali solution desulfurization device design is reasonable, while realizing double guarantee of desulfurization system, reduce the generation amount of solid waste, can also synergistically control a part of nitrogen oxides, reduce subsequent ammonia water consumption, reduce the degree of corrosion to equipment.

Description

Technical Field

[0001] This utility model relates to fluidized bed incinerator devices, and particularly to in-furnace and post-furnace alkaline desulfurization devices for waste fluidized bed incinerators. Background Technology

[0002] Fluidized bed incinerators for waste have been expanded into the incineration of industrial waste due to their low nitrogen oxide emissions and complete combustion. Fluidized bed incinerators for special waste can employ in-furnace desulfurization (FBD) to simultaneously control nitrogen oxides. However, using in-furnace limestone FBD increases auxiliary fuel consumption and generates a large amount of solid waste, resulting in high costs. Furthermore, with increasingly stringent environmental regulations, in-furnace FBD alone is insufficient to meet nitrogen oxide emission requirements, necessitating the simultaneous use of non-linear recirculation (SNCR) denitrification. To reduce solid waste generation, the amount of limestone added to the furnace must be reduced. However, using SNCR combined with post-furnace desulfurization alone requires increasing ammonia usage, leading to increased ammonia escape and significant damage to downstream equipment. SCR denitrification, on the other hand, is too expensive. In this case, flue gas recirculation combined with SNCR coupled denitrification could be used, but due to site and space limitations, rebuilding a flue gas recirculation system is not suitable.

[0003] Currently, a Chinese patent, "A Sludge Fluidized Bed Incinerator Device with Flue Gas Recirculation Structure," publication number CN114484470A, has been found. This device includes an incineration assembly, a diversion device, a drying device, a primary dust collector, a hot air blower, a secondary dust collector, a desulfurization tower, and a waste heat boiler. The incineration assembly, waste heat boiler, and primary dust collector are sequentially connected via flue pipes. A secondary dust collector and a hot air blower are located at the outlet of the primary dust collector, and a desulfurization tower is located at the tail end of the secondary dust collector. The secondary dust collector and the desulfurization tower are connected via flue pipes. The outlet of the hot air blower is connected to the drying device via a flue pipe, and the drying device is connected to the incineration assembly via a pipeline. The incineration assembly includes a furnace body with a combustion chamber. The drying device includes a casing, which is intermittently connected to the combustion chamber via a pipeline. The furnace body has a slag outlet connected to the combustion chamber, and the casing has a flue gas outlet intermittently connected to the combustion chamber. This device generates a large amount of solid waste, and the large amount of nitrogen oxides produced can easily corrode the equipment. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of this utility model is to propose an in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator. The in-furnace and post-furnace alkaline desulfurization device for the waste fluidized bed incinerator is reasonably designed, which can reduce the amount of solid waste generated while achieving dual protection of the desulfurization system. At the same time, it can also control a portion of nitrogen oxides, reduce the amount of subsequent ammonia water used, and reduce the degree of corrosion to the equipment.

[0005] This utility model is implemented using the following solution.

[0006] This utility model relates to an in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator. Its features include: an upper cylindrical section, a lower conical section, and a reduced-diameter cylindrical section connected sequentially to form a single unit; a wind cap is provided at the junction of the lower conical section and the reduced-diameter cylindrical section; a primary air input pipe is provided on the side of the reduced-diameter cylindrical section to form a primary air chamber within the reduced-diameter cylindrical section; and a dense phase combustion chamber zone is formed within and above the conical section. The upper cylindrical section has numerous secondary air inlets distributed along its circumference to form a dilute phase combustion chamber zone within the upper cylindrical section and above the secondary air inlets. The lower conical section has several limestone injection inlets, and a limestone silo is connected to these inlets via a Roots blower and pipelines. The flue gas output end of the upper cylindrical section is sequentially connected to a waste heat recovery mechanism, a desulfurization tower, a bag filter, an induced draft fan, and a chimney.

[0007] Preferably, the desulfurization tower is connected in sequence to a first spray gun and a mixer, and the mixer is connected to a water tank and an alkali tank through pipelines.

[0008] Preferably, the bottom ash hopper of the bag filter is connected to the inlet pipe of the desulfurization tower via a pipeline.

[0009] Preferably, a second spray gun and a liquid mixing metering distributor are sequentially connected to the pipeline between the flue gas output end on the upper side of the upper cylindrical section and the waste heat recovery mechanism. The liquid mixing metering distributor is connected to an ammonia storage tank and a deoxygenated water tank through pipelines.

[0010] Preferably, the lower conical section is provided with multiple limestone injection ports evenly distributed in the circumferential direction.

[0011] Preferably, secondary air inlets are evenly distributed along the circumference of the upper cylindrical section.

[0012] The advantages of the in-furnace and post-furnace alkaline desulfurization device of this utility model are: 1. The combination of limestone desulfurization in the incinerator and semi-dry desulfurization by alkaline spraying after the furnace provides dual protection for the desulfurization system, and can ensure that sulfur dioxide emissions meet the standards even when incinerating waste with complex composition.

[0013] 2. By adding a small amount of limestone into the incinerator, the generation of nitrogen oxides can be suppressed, the amount of ammonia water used in subsequent SNCR can be reduced, the service life of subsequent equipment can be extended, and the generation of subsequent solid waste can be reduced.

[0014] 3. The incinerator is equipped with a desulfurization tower and bag filter after the furnace, which only produces solid waste and no wastewater. It also requires little space and has a simple process. Attached Figure Description

[0015] The present invention will be further described below with reference to the accompanying drawings;

[0016] Figure 1 This is a schematic diagram illustrating the working principle of this utility model;

[0017] Figure 2 , 3 yes Figure 1 A partial view;

[0018] Figure 4 This is a partial schematic diagram illustrating the working principle of an embodiment of this utility model. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0020] The fluidized bed incinerator 3 of this utility model, comprising an upper cylindrical section 301, a lower conical section 302, and a reduced-diameter cylindrical section 303 connected in sequence, is integrated with the upper cylindrical section 301, the lower conical section 302, and the reduced-diameter cylindrical section 303. An air cap 304 (an existing component with small holes through which high-speed airflow is ejected to agitate the bed material and promote fluidized combustion; this air cap is mounted on an air distribution plate, which is not shown in the diagram) is installed at the junction of the lower conical section and the reduced-diameter cylindrical section. The side of the cylindrical section is provided with a primary air inlet pipe 305 to form a primary air chamber 306 in the cylindrical section and a dense phase combustion chamber 1 in and above the conical section. The upper cylindrical section 301 is densely distributed with secondary air inlets 307 in the circumferential direction to form a dilute phase combustion chamber 2 in the upper cylindrical section and above the secondary air inlets. Specifically, the dense phase combustion chamber is located above the air cap and below the secondary air inlet in the fluidized bed incinerator. The discharge end of the screw feeder A1 is connected to the feed port below the secondary air inlet 307 on the fluidized bed incinerator 3.

[0021] Several limestone injection inlets 308 are provided on the lower conical section 302, and the limestone silo 6 is connected to the limestone injection inlets 308 through a Roots blower 7 and pipelines.

[0022] The flue gas outlet end of the upper cylindrical section 301 is connected in sequence to the waste heat recovery mechanism 8, the desulfurization tower 9, the bag filter 10, the induced draft fan 11 and the chimney 12; the desulfurization tower 9 is connected in sequence to the first spray gun 13 and the mixer 14, and the mixer 14 is connected to the water tank 15 and the alkali tank 16 (containing 30% alkali solution) through pipelines.

[0023] The bottom ash hopper 17 of the bag filter 10 is connected to the inlet pipe 901 of the desulfurization tower 9 through an inclined pipe. The inclined pipe facilitates the input of ash into the inlet pipe 901.

[0024] A second spray gun 17 and a liquid mixing metering distributor 18 are sequentially connected to the pipeline between the flue gas output end of the upper cylindrical section 301 and the waste heat recovery mechanism 8. The liquid mixing metering distributor is connected to an ammonia storage tank 19 and a deoxygenated water tank 20 through pipelines.

[0025] The specific working principle of the fluidized bed incinerator 3 with the above structure is as follows: Primary air is evenly distributed through primary air input pipe 305, primary air chamber 306, and air cap 304 and enters the dense phase zone 1 of the combustion chamber to assist in the incineration of waste; limestone in limestone bin 6 is introduced into the dense phase zone 1 of the combustion chamber through pipeline and limestone injection inlet 308 under the action of Roots blower 7. Limestone is heated and decomposed in the dense phase zone 1 of the combustion chamber, producing calcium oxide and carbon dioxide, which aggravates the oxygen-deficient combustion state in the dense phase zone 1 of the combustion chamber and inhibits the generation of nitrogen oxides. Among them, calcium oxide plays the role of removing part of sulfur dioxide.

[0026] Unburned portions in the fluidized bed incinerator 3 enter the dilute phase zone 2 of the upper combustion chamber, where they are further burned completely by secondary air entering through the secondary air inlet 307. The flue gas generated by combustion enters the desulfurization tower 9 after passing through the waste heat recovery mechanism 8 (or after passing through a superheater). Before passing through the waste heat recovery mechanism 8, the flue gas passes through the second spray gun 17, where ammonia water from the ammonia water storage tank 19 and deoxygenated water from the deoxygenated water tank 20 are evenly distributed by the liquid mixing metering distributor 18 (via the second spray gun 17) to remove nitrogen oxides from the flue gas. After passing through the waste heat recovery mechanism 8, the flue gas enters the desulfurization tower 9. Fresh water from the water tank 15 and 30% alkaline solution prepared from the alkaline solution tank 16 are mixed by the mixer 14 and atomized by the first spray gun 13 before being sprayed into the desulfurization tower 9. In the desulfurization tower 9, acidic gases such as sulfur dioxide in the flue gas react with the diluted alkaline solution atomized water to further remove sulfur dioxide and other acidic gases. The desulfurized flue gas enters the bag filter 10, where solid dust is removed from the flue gas through the filter bags. The clean flue gas is then led to the chimney 12 by the induced draft fan 11 for discharge.

[0027] Advantages of the in-furnace and post-furnace alkaline desulfurization device for this utility model of a waste fluidized bed incinerator:

[0028] 1. The combination of limestone desulfurization inside the incinerator and semi-dry desulfurization by spraying alkaline solution after the furnace provides dual protection for the desulfurization system, ensuring that sulfur dioxide emissions from complex waste materials meet emission standards.

[0029] 2. By adding a small amount of limestone into the incinerator, the generation of nitrogen oxides can be suppressed, the amount of ammonia water used in the subsequent process can be reduced, which helps to extend the service life of subsequent equipment and at the same time reduces the generation of subsequent solid waste.

[0030] 3. The incinerator is equipped with a desulfurization tower 9 and a bag filter 10, which only produces solid waste and no wastewater. It also requires little space and has a simple process.

[0031] One embodiment of the above-mentioned fluidized bed waste incinerator:

[0032] A screw feeder A1, a belt conveyor A2, a crusher A3, and a freezing chamber A4 for freezing oil sludge are sequentially connected in the upper part of the dense phase zone 1 of the combustion chamber of the fluidized bed incinerator, so that the oil sludge is fed into the upper part of the dense phase zone 1 of the combustion chamber of the fluidized bed incinerator 3 after being frozen and crushed.

[0033] The output end of the screw feeder A1 is connected to the upper part of the dense phase zone 1 of the combustion chamber, rather than to the dilute phase zone 2 of the combustion chamber. This is because the crushed oil residue forms a solid powder that can be used as an auxiliary fuel for combustion in the incinerator, which can reduce the amount of auxiliary coal used in the incinerator. If the oil residue powder is fed into the dilute phase zone 2 of the combustion chamber, it cannot be used as an auxiliary fuel, and the combustion will be incomplete.

[0034] The method of this embodiment involves freezing the viscous oil residue at low temperature in a freezing room until it becomes brittle and hard, then crushing it into powder using a pulverizer. The powder is then fed into the furnace via a screw feeder and incinerated. Since the crushed powder is fed into the dense phase zone 1 of the combustion chamber of the incinerator via a screw conveyor, the amount of auxiliary coal used in the incinerator can be reduced. Furthermore, the screw conveyor ensures a relatively stable amount of oil residue powder, which can stabilize the flue gas generated during combustion. This helps to ensure the uniformity of emissions such as sulfur dioxide, nitrogen oxides, and carbon monoxide from the flue gas, preventing the need for frequent adjustments to the control of the fluidized bed flue gas. In other words, it eliminates the need for frequent adjustments to the amount of desulfurizing agent added, thus avoiding waste caused by frequent adjustments to the desulfurizing agent.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. An in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator, characterized in that: The system comprises an upper cylindrical section, a lower conical section, and a reduced-diameter cylindrical section connected in sequence. A wind cap is installed at the junction of the lower conical section and the reduced-diameter cylindrical section. A primary air inlet pipe is located on the side of the reduced-diameter cylindrical section to form a primary air chamber within the reduced-diameter cylindrical section and a dense phase combustion chamber zone within and above the conical section. The upper cylindrical section has numerous secondary air inlets distributed along its circumference to form a dilute phase combustion chamber zone within the upper cylindrical section and above the secondary air inlets. The lower conical section has several limestone injection inlets, and a limestone silo is connected to these inlets via a Roots blower and piping. The flue gas outlet on the upper side of the upper cylindrical section is sequentially connected to a waste heat recovery mechanism, a desulfurization tower, a bag filter, an induced draft fan, and a chimney.

2. The in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator according to claim 1, characterized in that: The desulfurization tower is connected in sequence to a first spray gun and a mixer, and the mixer is connected to a water tank and an alkali tank through pipelines.

3. The in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator according to claim 2, characterized in that: The bottom ash hopper of the bag filter is connected to the inlet pipe of the desulfurization tower via a pipeline.

4. The in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator according to claim 3, characterized in that: A second spray gun and a liquid mixing metering distributor are sequentially connected to the pipeline between the flue gas output end on the upper side of the upper cylindrical section and the waste heat recovery mechanism. The liquid mixing metering distributor is connected to an ammonia storage tank and a deoxygenated water tank through pipelines.

5. The in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator according to claim 1, characterized in that: The lower conical section has multiple limestone injection ports evenly distributed along its circumference.

6. The in-furnace and post-furnace alkaline desulfurization device for a waste fluidized bed incinerator according to claim 1, characterized in that: The upper cylindrical section is provided with secondary air inlets evenly distributed along its circumference.

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