A sludge incineration flue gas treatment coupled drying system

Abstract

The present invention discloses a sludge incineration flue gas treatment and coupling drying system, which includes a sludge fluidized bed incinerator, an air preheater, an evaporator, an electrostatic precipitator, an acid removal tower, a dryer, an adsorption tower, a bag filter, a flue gas heat exchanger, a chimney, a desulfurization tower and a lime slurry tank. The present invention couples sludge drying with flue gas treatment, improves the utilization rate of high-temperature heat in the flue gas, greatly improves the economy, and the treated flue gas meets the national emission standards.

Description

Technical Field

[0001] The present invention belongs to the technical field of sludge treatment and disposal, and particularly relates to a sludge incineration flue gas treatment coupled with a drying system. Background Art

[0002] With the continuous improvement of national environmental protection requirements, the treatment and disposal of sludge have received more and more attention. Incinerating sludge after deep dehydration has the characteristics of "reduction, harmlessness, and resource utilization", so it is widely adopted. At the same time, a large amount of high-temperature flue gas is generated during the incineration process. How to maximize its treatment and make full use of it is a key issue for incinerating sludge after deep dehydration.

[0003] The patent with the publication number CN108613198A is a sludge incineration flue gas treatment process. The flue gas from sludge incineration passes through a heat exchanger, absorbs heat energy and then enters a water film dust collector to remove large particles of dust and continue to cool down, and then enters a condenser and an electrostatic precipitator in sequence, and finally a high-pressure blower is used to press the flue gas into a biochemical reaction tank.

[0004] The patent with the publication number CN108613198A only considers the flue gas disposal alone, fails to make full use of the high-temperature flue gas, resulting in certain heat losses in this process. At the same time, it separates the flue gas treatment from the sludge drying, fails to utilize the coupling advantages of the two, and there is room for optimization in the system. Summary of the Invention

[0005] Technical problems to be solved: In view of the above technical problems, the present invention provides a sludge incineration flue gas treatment coupled with a drying system, which can effectively solve the deficiencies of heat loss and poor economic benefits of the flue gas in the above sludge treatment process.

[0006] Technical solution: A sludge incineration flue gas treatment coupled with a drying system includes a sludge fluidized bed incinerator, an air preheater, an evaporator, an electrostatic precipitator, an acid removal tower, a dryer, an adsorption tower, a bag filter, a flue gas heat exchanger, a chimney, a desulfurization tower, and a lime slurry tank. An SNCR device is provided at the top of the furnace of the sludge fluidized bed incinerator. The flue gas outlet of the sludge fluidized bed incinerator is sequentially connected to the flue gas inlet of the acid removal tower through the air preheater, the evaporator, and the electrostatic precipitator. The flue gas outlet of the acid removal tower is connected to the flue gas inlet of the dryer. The flue gas outlet of the dryer is connected to the flue gas inlet of the adsorption tower. The flue gas outlet of the adsorption tower is connected to the first flue gas inlet of the flue gas heat exchanger through the bag filter. The flue gas outlet of the desulfurization tower is connected to the second flue gas inlet of the flue gas heat exchanger. The flue gas outlet of the flue gas heat exchanger is connected to the chimney. The liquid injection port of the acid removal tower is connected to the lime slurry tank. The sludge outlet of the dryer is connected to the sludge inlet of the sludge fluidized bed incinerator. The water outlet of the flue gas heat exchanger is connected to the lime slurry tank.

[0007] Preferably, a diversion pump is provided on the pipeline connecting the liquid injection port of the acid removal tower to the lime slurry tank.

[0008] Preferably, the adsorption tower uses activated carbon as an adsorbent.

[0009] Preferably, induced draft fans are provided on the pipelines connecting the smoke outlet of the sludge fluidized bed incinerator to the smoke inlet of the air preheater, the smoke outlet of the acid removal tower to the smoke inlet of the dryer, the smoke outlet of the dryer to the smoke inlet of the adsorption tower, the pipeline connecting the bag filter to the first smoke inlet of the flue gas heat exchanger, and the pipeline connecting the smoke outlet of the desulfurization tower to the second smoke inlet of the flue gas heat exchanger.

[0010] Preferably, gas flow meters are provided on the pipeline connecting the bag filter to the first smoke inlet of the flue gas heat exchanger and the pipeline connecting the smoke outlet of the desulfurization tower to the second smoke inlet of the flue gas heat exchanger.

[0011] Preferably, the ammonia consumption of the SNCR device is adjusted in a timely manner according to the NOx concentration in the flue gas.

[0012] Beneficial effects: First, the flue gas treatment is coupled with sludge drying, and the high-temperature heat in the flue gas is fully utilized to complete the drying of the sludge. Second, the sludge is dried by the hot flue gas between the dry method and the semi-dry method. A certain amount of lime brought in during the semi-dry method of purifying the flue gas can effectively inhibit the acidic gas generated during the sludge drying process. At the same time, the dry method can further remove the acidic gas generated during the drying process, effectively solving the problem of flue gas treatment during drying. Third, the hot flue gas from the bag filter and the cold flue gas from the desulfurization tower are heat-exchanged through the flue gas heat exchanger, which is beneficial to flue gas emission. Fourth, since the flue gas contains a large amount of waste steam generated during the sludge drying process, after being cooled by the flue gas heat exchanger, this part of the steam condenses into condensate, and the condensate is used to prepare the semi-dry method lime slurry, which can effectively reduce the amount of wastewater treatment in the later stage and achieve the purpose of energy conservation. Description of the Drawings

[0013] Figure 1 is a schematic diagram of the sludge incineration flue gas treatment and coupling drying system of the present invention;

[0014] Numbers in the figure: 1, sludge fluidized bed incinerator; 2, air preheater; 3, evaporator; 4, electrostatic precipitator; 5, acid removal tower; 6, dryer; 7, adsorption tower; 8, bag filter; 9, flue gas heat exchanger; 10, chimney; 11, desulfurization tower; 12, SNCR device; 13, lime slurry tank. Detailed Embodiments

[0015] The present invention will be described in detail below with reference to the drawings and specific embodiments:

[0016] Example 1

[0017] As shown Figure 1 , a sludge incineration flue gas treatment and coupling drying system includes a sludge fluidized bed incinerator 1, an air preheater 2, an evaporator 3, an electrostatic precipitator 4, an acid removal tower 5, a dryer 6, an adsorption tower 7, a bag filter 8, a flue gas heat exchanger 9, a chimney 10, a desulfurization tower 11 and a lime slurry tank 13. An SNCR device 12 is provided at the top of the furnace chamber of the sludge fluidized bed incinerator 1. The flue gas outlet of the sludge fluidized bed incinerator 1 is sequentially connected to the flue gas inlet of the acid removal tower 5 through the air preheater 2, the evaporator 3, and the electrostatic precipitator 4. The flue gas outlet of the acid removal tower 5 is connected to the flue gas inlet of the dryer 6. The flue gas outlet of the dryer 6 is connected to the flue gas inlet of the adsorption tower 7. The flue gas outlet of the adsorption tower 7 is connected to the first flue gas inlet of the flue gas heat exchanger 9 through the bag filter 8. The flue gas outlet of the desulfurization tower 11 is connected to the second flue gas inlet of the flue gas heat exchanger 9. The flue gas outlet of the flue gas heat exchanger 9 is connected to the chimney 10. The liquid injection port of the acid removal tower 5 is connected to the lime slurry tank 13. The sludge outlet of the dryer 6 is connected to the sludge inlet of the sludge fluidized bed incinerator 1. The water outlet of the flue gas heat exchanger 9 is connected to the lime slurry tank 13.

[0018] A diversion pump is provided on the pipeline connecting the liquid injection port of the above-mentioned acid removal tower 5 and the lime slurry tank 13.

[0019] The above-mentioned adsorption tower 7 uses activated carbon as an adsorbent.

[0020] On the pipeline connecting the flue gas outlet of the above-mentioned sludge fluidized bed incinerator 1 and the flue gas inlet of the air preheater 2, on the pipeline connecting the flue gas outlet of the acid removal tower 5 and the flue gas inlet of the dryer 6, on the pipeline connecting the flue gas outlet of the dryer 6 and the flue gas inlet of the adsorption tower 7, on the pipeline connecting the bag filter 8 and the first flue gas inlet of the flue gas heat exchanger 9, and on the pipeline connecting the flue gas outlet of the desulfurization tower 11 and the second flue gas inlet of the flue gas heat exchanger 9, induced draft fans are provided.

[0021] On the pipeline connecting the bag filter 8 and the first flue gas inlet of the flue gas heat exchanger 9, and on the pipeline connecting the flue gas outlet of the desulfurization tower 11 and the second flue gas inlet of the flue gas heat exchanger 9, gas flow meters are provided.

[0022] The ammonia consumption of the above-mentioned SNCR device 12 is adjusted in a timely manner according to the NOx concentration in the flue gas.

[0023] The dry sludge is incinerated in the sludge fluidized bed incinerator 1, and SNCR denitration is carried out at the top simultaneously; the hot flue gas generated by incineration successively passes through the air preheater 2, the evaporator 3, the electrostatic precipitator 4, and the acid removal tower 5, and then enters the dryer 6 to dry the wet sludge. The high-temperature flue gas after drying first passes through the activated carbon in the adsorption tower 7 to remove the acid gas and dioxin therein, and then passes through the bag filter 8 and exchanges heat with the flue gas generated by the desulfurization tower 11 in the flue gas heat exchanger 9, reducing the temperature of the hot flue gas and at the same time increasing the temperature of the low-temperature flue gas generated by the desulfurization tower 11, so that the discharged flue gas meets the national standards; since the hot flue gas passes through the sludge dryer 6 and carries a large amount of moisture, after the temperature is reduced in the flue gas heat exchanger 9, the wastewater is condensed, and this part of the wastewater can be used as the preparation water for the semi-dry lime slurry to achieve the purpose of reuse; the dry sludge dried in the dryer 6 is sent to the sludge fluidized bed incinerator 1 for incineration treatment; the whole system realizes the purpose of making full use of the high-temperature flue gas.

[0024] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sludge incineration flue gas treatment coupled drying system, characterized in that: It includes a sludge fluidized bed incinerator (1), an air preheater (2), an evaporator (3), an electrostatic precipitator (4), an acid removal tower (5), a dryer (6), an adsorption tower (7), a bag filter (8), a flue gas heat exchanger (9), a chimney (10), a desulfurization tower (11) and a lime slurry tank (13). An SNCR device (12) is provided at the top of the furnace chamber of the sludge fluidized bed incinerator (1). The flue gas outlet of the sludge fluidized bed incinerator (1) is sequentially communicated with the flue gas inlet of the acid removal tower (5) through the air preheater (2), the evaporator (3) and the electrostatic precipitator (4). The flue gas outlet of the acid removal tower (5) is communicated with the flue gas inlet of the dryer (6). The flue gas outlet of the dryer (6) is communicated with the flue gas inlet of the adsorption tower (7). The flue gas outlet of the adsorption tower (7) is communicated with the first flue gas inlet of the flue gas heat exchanger (9) through the bag filter (8). The flue gas outlet of the desulfurization tower (11) is communicated with the second flue gas inlet of the flue gas heat exchanger (9). The flue gas outlet of the flue gas heat exchanger (9) is communicated with the chimney (10). The liquid injection port of the acid removal tower (5) is connected to the lime slurry tank (13). The sludge outlet of the dryer (6) is communicated with the sludge inlet of the sludge fluidized bed incinerator (1). The water outlet of the flue gas heat exchanger (9) is communicated with the lime slurry tank (13).

2. The sludge incineration flue gas treatment coupled drying system according to claim 1, wherein: A diversion pump is provided on the pipeline where the liquid injection port of the acid removal tower (5) is communicated with the lime slurry tank (13).

3. The sludge incineration flue gas treatment coupled drying system according to claim 1, characterized in that: The adsorption tower (7) uses activated carbon as an adsorbent.

4. A sludge incineration flue gas treatment coupled drying system according to claim 1, characterized in that: Induced draft fans are provided on the pipeline where the flue gas outlet of the sludge fluidized bed incinerator (1) is communicated with the flue gas inlet of the air preheater (2), on the pipeline where the flue gas outlet of the acid removal tower (5) is communicated with the flue gas inlet of the dryer (6), on the pipeline where the flue gas outlet of the dryer (6) is communicated with the flue gas inlet of the adsorption tower (7), on the pipeline where the bag filter (8) is communicated with the first flue gas inlet of the flue gas heat exchanger (9), and on the pipeline where the flue gas outlet of the desulfurization tower (11) is communicated with the second flue gas inlet of the flue gas heat exchanger (9).

5. A sludge incineration flue gas treatment coupled drying system according to claim 4, characterized in that: Gas flow meters are provided on the pipeline where the bag filter (8) is communicated with the first flue gas inlet of the flue gas heat exchanger (9) and on the pipeline where the flue gas outlet of the desulfurization tower (11) is communicated with the second flue gas inlet of the flue gas heat exchanger (9).

6. The sludge incineration flue gas treatment coupled drying system according to claim 1, wherein: The ammonia consumption of the SNCR device (12) is adjusted in a timely manner according to the NOx concentration in the flue gas.

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