CN104329676A - Fluidized bed sludge incineration system and processing method - Google Patents

Abstract

The invention discloses a fluidized bed sludge incineration system and a treatment method. The fluidized bed sludge incineration system includes a sludge incineration device, a two-stage heat exchange device, a washing and dust removal device, a secondary combustion device, and a sludge incineration device Including the fluidized bed incinerator, the two-stage heat exchange device includes a primary heat exchanger and a secondary heat exchanger, the heat channel of the primary heat exchanger communicates with the top gas outlet of the fluidized bed incinerator, and the primary heat exchanger The heat channel of the secondary heat exchanger is also connected in series with the heat channel of the secondary heat exchanger. It communicates with the fluidized bed incinerator, and the cold channel of the secondary heat exchanger communicates with the secondary combustion device. It is equipped with multi-stage heat exchange to achieve heat recovery and utilization. At the same time, the heat recovery heating system is used to solidify and absorb the exhaust gas first, and then burn it secondary, so that the cost and volume of the secondary combustion device are minimized.

Description

Fluidized bed sludge incineration system and treatment method

technical field

The invention relates to a sorting treatment device and a treatment method for garbage, and belongs to the technical field of environmental protection sludge treatment.

Background technique

At present, the discharge of urban industrial wastewater and domestic sewage is increasing day by day, the amount of sewage treatment is increasing, and the sludge output of sewage treatment plants is also increasing sharply. While using physical, chemical and biological methods to treat sewage, a large amount of excess sludge will be produced. Among them, the sludge with high organic content must be treated and disposed of in time, otherwise it will cause secondary pollution. The final solution of sludge is mainly used: landfill , agricultural, drying and incineration. Due to industrial development, the content of heavy metals in sludge has exceeded the standard in most cases and cannot be directly used for agriculture. At the same time, due to the continuous reduction of landfill area, the distance of sludge transportation is getting farther and farther. Although the sludge has been dehydrated, its moisture content is still high, which makes it difficult for landfills to accept, which in turn leads to the inability to landfill or the continuous increase in landfill costs. The traditional sludge treatment method, that is, simply performing mechanical concentration and dehydration treatment in the sewage treatment plant, can no longer meet the treatment requirements and standards at the present stage.

In the traditional technology, there is a patent document titled sludge and waste co-incineration thermoelectric treatment system. The sludge and waste co-incineration thermoelectric treatment system includes a waste incineration system, a sludge incineration system, and an exhaust gas treatment system. Among them, the waste incineration system includes Grate furnace, the hot gas discharge channel of the grate furnace is connected to the boiler, and the steam outlet of the boiler is connected to the steam header, and the steam output port of the steam header is divided into steam output port A, steam output port B, steam output port C, steam output port Output port D, steam output port A is connected back to the boiler after passing through the deaerator, steam output port B is connected to the deaerator through the steam condenser and then connected to the boiler, and steam output port C is connected to the deaerator after passing through the steam turbine generator. Oxygenator, the steam output port D is connected to the deaerator after passing through the waste heat utilization device; the sludge incineration system includes a wet sludge bin, a sludge rotary dryer, a fluidized bed sludge incinerator, and a sludge rotary dryer connected in sequence. The heat supply end of the dryer is connected to the waste heat utilization device, the sludge output port of the sludge rotary dryer is connected to the fluidized bed sludge incinerator and the wet sludge bin, and the hot exhaust gas of the fluidized bed sludge incinerator is separated After that, hot flue gas and waste dust gas are formed. The hot flue gas enters the boiler, and the waste dust gas enters the waste gas treatment system. fan, chimney; the connecting pipeline between the evaporation reaction tower and the bag reactor is connected with a dosing device, the steam flue gas heater is connected with an ammonia addition device, and the solidified product outlet of the evaporation reaction tower and the solidified product outlet of the bag reactor are connected to the fly The ash solidification bin, the waste gas of the fluidized bed sludge incinerator enters the bag reactor, and the waste gas of the boiler enters the evaporation reaction tower.

The composition of sewage sludge is very complex. In addition to containing a large amount of water, it also contains a large amount of useful resources. After drying, the sludge can be used for land improvement, building materials utilization, etc., but the moisture content is generally required to be below 55%. Sludge drying methods include: natural air drying, direct heating and indirect heating. How to reduce the moisture content of sludge, reduce energy consumption, and reduce secondary pollution are the key technologies for sludge treatment. The traditional method of sludge incineration is: first dehydrate and concentrate the sludge with a moisture content of more than 99%, and then make the moisture content of the sludge below 80%. At this time, the dehydration and concentration method cannot further reduce the moisture content of the sludge. At this time, it is necessary to use a drying machine to evaporate the moisture in the sludge by means of electric heating or natural gas heating, so that the moisture content of the sludge can be further reduced to below 60%. At this time, the sludge can be burned by high temperature heating The substances in the sludge are burned, and the flue gas to be treated is directly or indirectly treated and discharged. Therefore, in the traditional sludge incineration technology, an independent flue gas treatment equipment is required, which will undoubtedly increase equipment costs and maintenance costs. , Sometimes the owner directly discharges the generated flue gas in order to reduce the cost, causing secondary pollution, which does not meet the country's environmental protection needs.

Contents of the invention

The purpose of the present invention is to provide a fluidized bed sludge incineration system and treatment method, which is equipped with multi-stage heat exchange to achieve heat recovery and utilization. At the same time, the heat recovery heating system is used to solidify and absorb the waste gas first, and then secondly Combustion minimizes the cost and volume of the secondary combustion device, reducing input and operating costs.

The purpose of the present invention is mainly achieved through the following technical solutions: a fluidized bed sludge incineration system, including a sludge incineration device, a two-stage heat exchange device, a washing and dust removal device, and a secondary combustion device, and the sludge incineration device includes a fluidized bed incinerator The two-stage heat exchange device includes a primary heat exchanger and a secondary heat exchanger. The heat channel of the primary heat exchanger is connected with the top gas outlet of the fluidized bed incinerator, and the heat channel of the primary heat exchanger is also connected with the secondary heat exchanger. The heat channels of the primary heat exchanger are connected in series, the heat channels of the secondary heat exchanger are connected with the scrubbing and dust removal device, and the scrubbing and dust removal device is also connected with the secondary combustion device, and the cold channel of the primary heat exchanger is connected with the fluidized bed incinerator In communication, the cooling channel of the secondary heat exchanger communicates with the secondary combustion device.

The structural principle of the present invention is as follows: the sludge with high humidity is dried in the early stage of the sludge incinerator, and then burned by the fluidized bed incinerator in the sludge incinerator to form a mixture of exhaust gas particles, and then passed through the two-stage exchange process. The primary heat exchanger of the thermal device recovers the heat in the mixture of exhaust gas particles to the fluidized bed incinerator to provide heat for the fluidized bed incinerator. Carry out heat recovery, and at the same time input heat into the secondary combustion device to preheat the secondary combustion device to recover heat and save energy. The acid gas and dust particles in the gas are washed into solid matter and discharged, and the remaining gas enters the secondary combustion device, and the preheated gas is reburned and absorbed before being discharged into the atmosphere. The system set up in this way has little air pollution, no particulate matter is discharged into the atmosphere, and effectively alleviates the generation of smog.

Preferably, the sludge incinerator also includes a sludge tank, a sludge dehydrator, and a sludge dryer connected in sequence, and the fluidized bed incinerator includes a preheater connected to the inside of the fluidized bed incinerator, and the preheater and sludge The dryer is connected, the preheater is connected with the cooling passage of the primary heat exchanger, and the fluidized bed incinerator is also connected with a sand storage tank.

The sludge stored in the sludge tank is first dehydrated by the sludge dewatering machine to remove most of the water in the sludge, and then dried by the sludge dryer to finally form sludge with less water content. The sludge is sent to the fluidized bed incinerator for combustion treatment, so that the combustible substances in the sludge are decomposed to form heat, and the heat is recycled by the cold passage of the primary heat exchanger, and the preheater is used to absorb the cold passage for recovery The heat, and then heat the sludge, so that the sludge entering the fluidized bed incinerator is easily ignited.

Preferably, in order to provide sufficient oxygen, the fluidized bed incinerator is connected with an air compressor.

Preferably, the washing and dedusting device includes a Venturi scrubber, a tray scrubber, and a wet electrostatic precipitator connected in sequence, and the Venturi scrubber communicates with the heat channel of the secondary heat exchanger, and also includes a caustic supply that communicates with the caustic storage Pump, caustic feed pump communicates with venturi scrubber and wet electrostatic precipitator simultaneously, bottom of tray scrubber and wet electrostatic precipitator communicates with ash hopper simultaneously, top of wet electrostatic precipitator communicates with secondary burner .

The exhaust gas particulate mixture output by the secondary heat exchanger enters the Venturi scrubber, tray scrubber, and wet electrostatic precipitator for exhaust gas and particulate matter washing and precipitation. The caustic is blown into the Venturi scrubber and the wet electrostatic precipitator to react with the exhaust gas and absorb the acid gas in it. The caustic soda powder can be evenly distributed into the Venturi scrubber and the wet electrostatic precipitator by using the caustic soda feed pump , can greatly absorb acid gas, and particulate matter can also be absorbed, and at the same time too much particulate matter can be absorbed by the wet electrostatic precipitator, and finally the gas output from the wet electrostatic precipitator no longer contains acid gas and particulate matter. Effective separation of acid gases and particulate matter.

The top of the wet electrostatic precipitator is connected with a cleaning fan.

The separated exhaust gas enters the secondary combustion device for secondary combustion treatment. The secondary combustion device includes a burner, a carbon absorber, and a chimney connected in sequence. The burner is connected to the washing and dust removal device. The cold channel is connected. The burner ignites its gas, burns the unburned substances in the exhaust gas, and then is absorbed by the carbon absorber, and finally the exhaust gas is discharged.

Preferably, it also includes a preheating fan and a fluidization fan connected to each other. The fluidization fan is connected to the input end of the cold capacity channel of the primary heat exchanger, and the fluidization fan is connected to the output end of the cold capacity channel of the primary heat exchanger. The preheating fan is communicated with the output end of the cold channel of the primary heat exchanger, and the preheating fan is communicated with the fluidized bed incinerator.

The treatment method based on the above-mentioned fluidized bed sludge incineration system includes the following steps:

A. Sludge drying step: the sludge in the sludge tank is dried after passing through a sludge dehydrator and a sludge dryer;

B. Sludge incineration step: send the dried sludge in the previous step into the fluidized bed incinerator for combustion;

C. Heat exchange step: input the exhaust gas particle mixture output from the top outlet of the fluidized bed incinerator into the heat channel of the primary heat exchanger, and exchange heat between the heat channel and the cold channel of the primary heat exchanger to convert the The heat absorbed by the exhaust gas particle mixture, the absorbed heat flows back into the fluidized bed incinerator, the cooled exhaust gas particle mixture flows into the heat channel of the next secondary heat exchanger, and passes through the heat channel of the secondary heat exchanger and the cooling The heat exchange of the measuring channel absorbs the heat of the mixture of exhaust gas particles, and the absorbed heat flows into the secondary combustion device;

D. Washing and dust removal step: input the exhaust gas particle mixture in the heat channel of the secondary heat exchanger into the washing and dust removal device, and go through the washing and dust removal treatment of Venturi scrubber, tray scrubber, and wet electrostatic precipitator;

E. Secondary combustion step: input the exhaust gas output from the wet electrostatic precipitator into the secondary combustion device for combustion again.

In the scrubbing and dedusting step, both the Venturi scrubber and the wet electrostatic precipitator will introduce dusty caustic alkali to mix with the waste gas particle mixture to absorb the acid gas in the waste gas particle mixture.

To sum up, the beneficial effects of the present invention are: effective and large-scale treatment of sludge, effective separation of combusted waste gas, good separation effect, low cost, and low-carbon and environmentally friendly emissions.

Description of drawings

Fig. 1 is a structural schematic diagram of the present invention.

The names corresponding to the reference signs in the attached drawings are: 1. Sludge tank, 2. Sludge dehydrator, 3. Sludge dryer, 4. Fluidized bed incinerator, 5. Gas, 6. Preheater, 7. Sand storage tank, 8. Air compressor, 9. Preheating fan, 10. Fluidizing fan, 11. Primary heat exchanger, 12. Secondary heat exchanger, 13. Reheating fan, 14. Burner , 15. Carbon absorber, 16. Chimney, 17. Venturi scrubber, 18. Tray scrubber, 19. Wet electrostatic precipitator, 20. Cleaning fan, 21. Caustic storage, 22. Caustic feeding pump , 23, ash bucket.

Detailed ways

The present invention will be further described in detail below in conjunction with the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

Example 1:

As shown in Figure 1,

The fluidized bed sludge incineration system includes a sludge incineration device, a two-stage heat exchange device, a washing and dust removal device, and a secondary combustion device. The sludge incineration device includes a fluidized bed incinerator 4, and the two-stage heat exchange device includes a primary exchange Heater 11 and secondary heat exchanger, the heat passage of primary heat exchanger 11 communicates with the top gas outlet of fluidized bed incinerator 4, the heat passage of primary heat exchanger 11 is also connected with the heat of secondary heat exchanger The channels are connected in series, the heat channel of the secondary heat exchanger is connected with the washing and dust removal device, and the washing and dust removal device is also connected with the secondary combustion device, the cold channel of the primary heat exchanger 11 is connected with the fluidized bed incinerator 4, and the secondary The cooling channel of the heat exchanger communicates with the secondary combustion device.

The structural principle of the present invention is: the sludge with high humidity is dried in the early stage of the sludge incinerator, and then burned by the fluidized bed incinerator 4 in the sludge incinerator to form a mixture of exhaust gas particles, and then passed through two stages The primary heat exchanger 11 of the heat exchange device recovers the heat in the exhaust gas particle mixture to the fluidized bed incinerator 4 to provide heat for the fluidized bed incinerator 4, and at the same time, the secondary heat exchanger of the two-stage heat exchange device again Heat recovery is carried out on the mixture of exhaust gas particles, and at the same time, the heat is input to the secondary combustion device for preheating, so as to recover heat and save energy. The acid gas and dust particles in the exhaust gas particle mixture are washed into solid matter and discharged, and the remaining gas enters the secondary combustion device, and the preheated gas is reburned and absorbed before being discharged into the atmosphere. The system set up in this way has little air pollution, no particulate matter is discharged into the atmosphere, and effectively alleviates the generation of smog.

Preferably, the sludge incinerator also includes a sludge tank 1, a sludge dewaterer 2, and a sludge dryer 3 connected in sequence, and the fluidized bed incinerator 4 includes a preheater 6 connected to the inside of the fluidized bed incinerator 4, The preheater 6 is in communication with the sludge dryer 3 , the preheater 6 is in communication with the cooling channel of the primary heat exchanger 11 , and the fluidized bed incinerator 4 is also in communication with a sand storage tank 7 .

The sludge stored in the sludge tank is first dehydrated by the sludge dehydrator 2 to remove most of the water in the sludge, and then dried by the sludge dryer 3 to finally form sludge with less water content. The sludge is sent to the fluidized bed incinerator 4 for combustion treatment, so that the combustible substances in the sludge are decomposed to form heat, and the heat is recycled by the cold channel of the primary heat exchanger 11. Using the preheater 6 Absorb the heat recovered by the cold channel, and then heat the sludge, so that the sludge entering the fluidized bed incinerator 4 is easily ignited.

Preferably, in order to provide sufficient oxygen, the fluidized bed incinerator 4 is connected with an air compressor 8 .

Preferably, the washing and dedusting device includes a Venturi scrubber 17, a tray scrubber 18, and a wet electrostatic precipitator 19 connected in sequence. The Venturi scrubber 17 communicates with the heat channel of the secondary heat exchanger, and also includes a caustic alkali tank 21. The caustic alkali feed pump 22, the caustic alkali feed pump 22 communicates with the Venturi scrubber 17 and the wet electrostatic precipitator 19 at the same time, and the bottom of the tray scrubber 18 and the wet electrostatic precipitator 19 communicate with the ash hopper 23 at the same time, The top of the wet electrostatic precipitator 19 communicates with the secondary combustion device.

The exhaust gas particle mixture output by the secondary heat exchanger enters the Venturi scrubber 17, the tray scrubber 18, and the wet electrostatic precipitator 19 for washing and sedimentation of the exhaust gas and particulate matter. The caustic in the alkali tank 21 is blown into the Venturi scrubber 17 and the wet electrostatic precipitator 19 to react with the waste gas and absorb the acid gas therein, and the caustic in powder form can be evenly distributed into the Venturi by using the caustic soda feed pump 22 In the scrubber 17 and the wet electrostatic precipitator 19, the acid gas can be greatly absorbed, and the particulate matter can also be absorbed. No more acid gas and particulate matter. Effective separation of acid gases and particulate matter.

The top of the wet electrostatic precipitator 19 is connected with a cleaning fan 20 .

The separated exhaust gas enters the secondary combustion device for secondary combustion treatment. The secondary combustion device includes a burner 14, a carbon absorber 15, and a chimney 16 connected in sequence. The burner 14 communicates with the washing and dust removal device. The cooling channel of the stage heat exchanger is connected. The burner 14 ignites its gas, burns the unburned substances in the waste gas, and then passes through the carbon absorber 15 for adsorption, and finally the waste gas is discharged.

Preferably, it also includes a preheating blower 9 and a fluidizing blower 10 communicated with each other, the fluidizing blower 10 communicates with the input end of the cold capacity channel of the primary heat exchanger 11, and the fluidizing blower 10 communicates with the cooling capacity of the primary heat exchanger 11 The output end of the channel is connected, the preheating fan 9 is connected with the output end of the cooling channel of the primary heat exchanger 11 , and the preheating fan 9 is connected with the fluidized bed incinerator 4 .

Example 2

The treatment method based on the above-mentioned fluidized bed sludge incineration system includes the following steps:

A. Sludge drying step: the sludge in the sludge tank is dried after passing through a sludge dehydrator and a sludge dryer;

B, sludge incineration step: send the dried sludge in the previous step into the fluidized bed incinerator 4 for combustion;

C. Heat exchange step: input the waste gas particle mixture output from the top outlet of the fluidized bed incinerator 4 into the heat channel of the primary heat exchanger 11, and pass the heat through the heat channel and the cold channel of the primary heat exchanger 11 Exchange, absorb the heat of the waste gas particle mixture, and the absorbed heat flows back into the fluidized bed incinerator 4, and the cooled waste gas particle mixture flows into the heat channel of the next secondary heat exchanger, and passes through the heat channel of the secondary heat exchanger. The heat exchange between the heat channel and the cold channel absorbs the heat of the mixture of exhaust gas particles, and the absorbed heat flows into the secondary combustion device;

D. Washing and dust removal step: input the exhaust gas particle mixture in the heat channel of the secondary heat exchanger into the washing and dust removal device, and go through the washing and dust removal treatment of Venturi scrubber, tray scrubber, and wet electrostatic precipitator;

E. Secondary combustion step: input the exhaust gas output from the wet electrostatic precipitator into the secondary combustion device for combustion again.

In the scrubbing and dedusting step, both the Venturi scrubber and the wet electrostatic precipitator will introduce dusty caustic alkali to mix with the waste gas particle mixture to absorb the acid gas in the waste gas particle mixture.

As described above, the present invention can be well realized.

Claims (9)

1. The fluidized bed sludge incineration system is characterized in that it includes a sludge incineration device, a two-stage heat exchange device, a washing and dust removal device, and a secondary combustion device. The sludge incineration device includes a fluidized bed incinerator (4), two The first-stage heat exchange device includes a first-stage heat exchanger (11) and a second-stage heat exchanger. The heat channel of the first-stage heat exchanger (11) communicates with the top gas outlet of the fluidized bed incinerator (4). The heat channel of the heat exchanger (11) is also connected in series with the heat channel of the secondary heat exchanger, the heat channel of the secondary heat exchanger is connected with the washing and dust removal device, and the washing and dust removal device is also connected with the secondary combustion device The cooling channel of (11) communicates with the fluidized bed incinerator (4), and the cooling channel of the secondary heat exchanger communicates with the secondary combustion device. 2. The fluidized bed sludge incineration system according to claim 1, characterized in that: the sludge incineration device also includes a sludge tank (1), a sludge dehydrator (2), and a sludge dryer ( 3), the fluidized bed incinerator (4) includes a preheater (6) connected to the interior of the fluidized bed incinerator (4), the preheater (6) is connected to the sludge dryer (3), and the preheater ( 6) It is connected with the cooling channel of the primary heat exchanger (11), and the fluidized bed incinerator (4) is also connected with a sand storage tank (7). 3. The fluidized bed sludge incineration system according to claim 2, characterized in that: the fluidized bed incinerator (4) is connected with an air compressor (8). 4. The fluidized bed sludge incineration system according to claim 1, characterized in that: the washing and dust removal device includes a Venturi scrubber (17), a tray scrubber (18), and a wet electrostatic precipitator (19) connected in sequence , the venturi scrubber (17) communicates with the heat channel of the secondary heat exchanger, and also includes the caustic soda feed pump (22) connected to the caustic soda tank (21), and the caustic soda supply pump (22) is connected with the venturi at the same time The scrubber (17) communicates with the wet electrostatic precipitator (19), the bottom of the tray scrubber (18) and the wet electrostatic precipitator (19) are simultaneously connected to the ash hopper (23), and the wet electrostatic precipitator (19) The top communicates with the secondary combustion device. 5. The fluidized bed sludge incineration system according to claim 4, characterized in that: a cleaning fan (20) is connected to the top of the wet electrostatic precipitator (19). 6. The fluidized bed sludge incineration system according to claim 1, characterized in that: the secondary combustion device includes a burner (14), a carbon absorber (15), a chimney (16), and a burner ( 14) It communicates with the washing and dust removal device, and the burner (14) communicates with the cooling channel of the secondary heat exchanger. 7. The fluidized bed sludge incineration system according to claim 1, characterized in that it also includes a preheating fan (9) and a fluidizing fan (10) connected to each other, and the fluidizing fan (10) is connected to the first stage The input end of the cooling channel of the heat exchanger (11) is connected, the fluidization fan (10) is connected with the output end of the cooling channel of the primary heat exchanger (11), the preheating fan (9) is connected with the primary heat exchanger (11 ) is connected to the output end of the cooling channel, and the preheating fan (9) is connected to the fluidized bed incinerator (4). 8. Based on the processing method of any fluidized bed sludge incineration system in claims 1 to 7, it is characterized in that: comprise the steps: A. Sludge drying step: the sludge in the sludge tank is dried after passing through a sludge dehydrator and a sludge dryer; B. Sludge incineration step: send the dried sludge in the previous step into the fluidized bed incinerator (4) for combustion; C. Heat exchange step: input the exhaust gas particle mixture output from the top outlet of the fluidized bed incinerator (4) into the heat channel of the primary heat exchanger (11), and pass through the heat channel of the primary heat exchanger (11) The heat exchange with the cold channel absorbs the heat of the waste gas particle mixture, and the absorbed heat flows back into the fluidized bed incinerator (4), and the cooled waste gas particle mixture flows into the heat channel of the next secondary heat exchanger , through the heat exchange between the heat channel and the cold channel of the secondary heat exchanger, the heat of the exhaust gas particle mixture is absorbed, and the absorbed heat flows into the secondary combustion device; D. Washing and dust removal step: input the exhaust gas particle mixture in the heat channel of the secondary heat exchanger into the washing and dust removal device, and go through the washing and dust removal treatment of Venturi scrubber, tray scrubber, and wet electrostatic precipitator; E. Secondary combustion step: input the exhaust gas output from the wet electrostatic precipitator into the secondary combustion device for combustion again. 9. The treatment method according to claim 8, characterized in that: in the washing and dedusting step, both the Venturi scrubber and the wet electrostatic precipitator will introduce dust-type caustic soda to mix with the waste gas particle mixture to absorb the dust in the waste gas particle mixture. Acid gas.