WO2010139168A1 - Digestion circulating fluidized bed flue gas desulfurization method and device - Google Patents

Abstract

A digestion circulating fluidized bed flue gas desulfurization method and device. The device comprises a prededusting section (12), a venture tube bundle section (2) and a digestion reaction section (8). Three stage atomization sprayers are arranged in this device. The lime used in the desulfurization method satisfies the following quality terms: T60 < 4 min, the CaO content > 80%, the particle size < 0.048 mm. The desulfurization reaction temperature is controlled to 75-90°C. Mainly by controlling the water amount of the second stage atomization spraying, the outlet temperature of the second stage deduster (24) is caused to no less than 70°C. The molar ratio of Ca/S is controlled to 1.0-1.6. The dwell time of the flue gas is controlled to 1-3 seconds.

Description

 Digestion circulating fluidized bed flue gas desulfurization method and device

 The invention belongs to the technical field of environmental protection, relates to industrial flue gas treatment technology, and particularly relates to a circulating fluidized bed flue gas desulfurization method and device.

Background technique

The steel industry is the pillar industry of China's national economy. But it is also a major polluter. Sintering production is an important process unit for modern steel production, contributing to the sulfur dioxide emissions of the steel industry as high as 40% to 60%. Therefore, it is important to control the emission of sulfur dioxide during the production of the sintering machine. Generally, the S0 ₂ emission reduction and control measures for sintering flue gas mainly include three methods: low sulfur raw material blending method, high chimney diffusion dilution method, and tail sintering flue gas desulfurization method. The tail sintering flue gas desulfurization method is a practical and effective method for solving the desulfurization of sintering flue gas. At present, the sintering flue gas desulfurization process can be basically divided into three categories: wet method, dry method and semi-dry method. Wet desulfurization mainly includes limestone-gypsum method, seawater method, magnesium hydroxide method and ammonia absorption method; dry desulfurization includes furnace-injected calcium tail flue gas humidification activated desulfurization method (LIFAC), electron beam method and charged dry powder The method of semi-drying includes spray drying (SDA), humidification ash cycle desulfurization (NID), circulating fluidized bed desulfurization (CFB), and the like. Since the dry desulfurization adopts a dry desulfurizing agent, the desulfurization by-product is also a dry solid, and there is no secondary pollution, and the market potential is great.

 The main problems existing in the existing dry and semi-dry flue gas desulfurization technologies are complicated system, large floor space, high construction cost and high operating cost, relatively low desulfurization efficiency, and large amount of by-product treatment.

Summary of the invention

 In view of the shortcomings of the current flue gas desulfurization technology, especially the dry process and the semi-dry flue gas desulfurization technology, the present invention combines the advantages of various flue gas desulfurization processes, especially on the basis of the circulating fluidized bed desulfurization method. A dry desulfurization process, a digestive circulating fluidized bed flue gas desulfurization method, and a digestive circulating fluidized bed flue gas desulfurization device have been developed.

 The digestive circulating fluidized bed flue gas desulfurization device of the present invention comprises a mill, a desulfurization tower and a bag filter, and the desulfurization tower is divided into three sections: a pre-dusting section (lower section), a venturi section (middle section), and a digestion reaction section ( Upper section).

 The lower part of the desulfurization tower is a pre-dusting section, the side wall is provided with a flue gas inlet, the bottom part is provided with a ash discharge port, and the installation ash discharge is provided, and a flue gas inlet baffle is arranged above the flue gas inlet of the pre-dust remover. The pre-dusting section is mainly used to remove coarse dust from the flue gas. The pre-dusting section uses a conventional gravity dust collector or a cyclone dust collector.

 The middle part of the desulfurization tower, that is, the upper part of the pre-dusting section is the venturi tube bundle section, and the inner longitudinal direction is closely arranged with a plurality of venturi tubes, the number of which depends on the inner diameter of the desulfurization tower, and can be valued empirically. The inner diameter of the tower is determined according to the amount of smoke.

The upper part of the desulfurization tower, that is, the upper part of the venturi section, is the digestion reaction section, the inner wall of the digestion reaction section, and the venturi section The side is provided with a desulfurizing agent injection inlet and a circulating ash injection inlet (the desulfurizing agent injection inlet and the circulating ash injection inlet are connected with the air chute or the pipeline). A three-stage atomizing nozzle is used, which is a digestive water nozzle or a spray gun, a humidifying water nozzle or a spray gun, a makeup water nozzle or a spray gun. A digesting water nozzle or a spray gun, a humidifying water nozzle or a spray gun is arranged in order from the bottom to the top of the desulfurizing agent injection inlet and the circulating ash jet inlet, and a supplementary water nozzle is arranged at the top of the digestion reaction section. A flue gas outlet is arranged on the upper side wall of the digestion reaction section, and a flue gas outlet deflector is arranged above the flue gas outlet in the digestion reaction section.

 The digestive circulating fluidized bed flue gas desulfurization method of the present invention is as follows.

 The block-shaped quicklime is ground into a quicklime powder by a mill, and after being classified, the lime powder having a particle size of <0.048 mm (lime quality requirement: CaO>80%, particle size <0.048 mm) is sent to the lime silo, and the pneumatic conveying method is adopted. The desulfurization agent is injected into the desulfurization tower, and the pressure of the conveying gas is controlled to be 0.2 to 1.0 MPa.

 The clean process water is sprayed into the desulfurization tower through the digesting water nozzle, the humidifying water nozzle and the supplementary water nozzle of the reaction section by a high-pressure pump, and the pressure of the sprayed water is controlled to be 0.1 to 2.5 MPa.

 It adopts three-stage atomized water spray and one-stage atomized water spray (can pass 0.1~0.5MPa compressed air to achieve better fogging effect). It is located above the middle section of the tower and above the venturi section, mainly for digesting quicklime. The secondary atomized water spray is mainly used to humidify the surface of the particles, reduce the temperature of the flue gas to create a suitable desulfurization reaction temperature, and can be used to further digest a very small amount of undigested lime (also can pass compressed air of 0.1~0.5MPa). To achieve better atomization effect). Three-stage atomized water spray (can pass the clean flue gas after treatment of 0.1~0.5MPa, that is, the secondary dust collector outlet flue gas to achieve better atomization effect). Located at the top of the tower, the water spray direction and the rising smoke The opposite direction of gas is beneficial to the formation of turbulence, prolonging the contact time of the desulfurizing agent with the flue gas, and adding an appropriate amount of humidifying water, thereby increasing the desulfurization rate of the system, and also adjusting the exhaust gas temperature.

 The flue gas is introduced into the desulfurization tower from the flue gas inlet of the pre-dusting section, and the flue gas is removed from the pre-dusting section to reduce the load of the subsequent dedusting and purifying device, and at the same time increase the collision probability of the sulfur dioxide and the desulfurizing agent in the flue gas, which is beneficial to the flue gas. Desulfurization. After removing the large particle dust, the flue gas rises to the venturi section, and enters the digestion reaction section at high speed under the action of the venturi tube. The flow state becomes intense turbulence, and the process water and desulfurization sprayed into the desulfurization tower. Agent and circulating ash mass transfer, heat transfer, under the conditions of digestion, humidification, cooling (desulfurization reaction temperature is 75~90 °C), slaked lime reacts with sulfur dioxide in flue gas to form calcium sulfite, part of calcium sulfite It is oxidized by air to calcium sulfate, and sulfur dioxide in the flue gas is removed. The flue gas after desulfurization is discharged from the flue gas outlet at the upper part of the tower, and enters the secondary dust collector through the flue gas pipeline.

The secondary dust collector adopts electrostatic precipitator or bag filter with dust removal efficiency above 99%, and there are two outlets at the bottom of the ash bin. One circulating ash outlet is connected to the circulating ash jet inlet of the desulfurization tower through a pipeline or air chute. In the pneumatic conveying method, the pressure of the conveying gas is controlled to be 0.1 to 1.0 MPa, and the circulating ash is sprayed into the desulfurization tower, and the circulating ash is heated to 60 to 90 ° C by steam or other heating method to facilitate transportation. The other outlet of the bottom ash silo is the ash outlet, through which the ash is discharged out of the ash yard. Part of the circulating ash collected by the secondary dust collector is adjusted by the amount of recirculating feed, and the ash concentration of the flue gas outlet of the secondary dust collector is kept in the range of < 10?/!11 ³ , and the clean flue gas is discharged into the chimney through the induced draft fan and discharged. atmosphere. In the process, the secondary atomization water spray quantity is mainly controlled, so that the secondary dust collector outlet flue gas temperature can be 70 ° C. The control Ca/S molar ratio is 1.0 to 1. 6. The control flue gas residence time is 1 to 3 seconds.

 The main process features and advantages of the present invention are as follows:

 (1) The process adopts dry feeding mode to avoid problems such as corrosion and blockage caused by wet feeding mode.

(2) The desulfurization efficiency is high. When the ratio of calcium to sulfur is 1.2~1.3, the desulfurization efficiency can reach more than 90%. At the same time, most of the S0 ₃ , HCK HF and other polluting gases in the flue gas can be removed.

 (3) The digestive circulating fluidized bed desulfurization tower integrates pre-dusting, lime digestion and desulfurization functions, and integrates the pre-duster, lime digestion reactor and circulating fluidized bed desulfurization tower, which can save system land occupation and reduce equipment. investment.

 (4) Since the desulfurization powder is very fine, the particle size is <0.048mm, the tiny quicklime particles are digested with water in the tower to form finer slaked lime particles, ensuring that the lime is fully digested, and the fine slaked lime particles are split by the reaction heat. It is more conducive to desulfurization, combined with the mass transfer of the materials in the reaction section and the strengthening of the heat transfer process. The digestion and desulfurization reactions are carried out at the same time. The digestion time and reaction time are very short, which can be completed in 1~3 seconds. The height of the tower is thus greatly reduced, thereby reducing investment. The lime digestion reactor is omitted, which further reduces engineering investment and operating costs. The investment and operating costs can be saved by 10~30% compared with the current dry and semi-dry technologies.

 (5) The processing and transportation of massive lime on site ensures the activity of quicklime and creates conditions for rapid and efficient desulfurization.

 (6) The process flow is simple, the system reliability is high, the floor space is small, and the system layout is flexible. It is very suitable for the transformation of existing units and new units with tight facilities.

 (7) There is no desulfurization wastewater discharge in the process, and the desulfurization by-products are dry, which can realize the recycling of desulfurization ash.

 (8) The desulfurization powder adopts quicklime with a particle size of <0.048 mm, and the lime is digested in the desulfurization tower, thereby avoiding the problems and problems such as insufficient digestion or high water content brought by the extra-column digester.

 (9) Setting the venturi tube bundle is conducive to the formation of turbulent flow in the desulfurization tower, strengthens the internal circulation of the desulfurizer, and improves the utilization rate of the desulfurizer and the desulfurization efficiency. At the upper end of the venturi tube section (desulfurization tower digestion reaction section), the desulfurizing agent and atomized water are sprayed, which reduces the resistance loss in the tower, which is beneficial to the whole system operation and low running cost.

DRAWINGS

1 is a schematic structural view of a desulfurization tower of a flue gas desulfurization device for a digestive circulation fluidized bed according to the present invention;

2 is a process flow diagram of a digestive circulating fluidized bed flue gas desulfurization method according to the present invention;

In the picture: 1 flue gas inlet, 2 venturi tube bundle section, 3 desulfurizer injection inlet, 4 humidification water nozzle, 5 supplementary water nozzle, 6 flue gas outlet deflector, 7 flue gas outlet, 8 digestion reaction section, 9 Digestive water nozzle, 10 flue gas inlet deflector, 11 brackets, 12 pre-dusting section, 13 rows of gray pottery, 14-cycle ash jet inlet, 15 digestive water inlet, 16 humidified water inlet, 17-block lime inlet Mouth, 18 mill, 19 ultra-fine lime powder bin, 20 desulfurizer air chute, 21 supplementary water inlet, 22 flue gas outlet pipe, 23 secondary dust collector flue gas inlet, 24 secondary dust collector, 25 secondary dust removal Flue gas outlet, 26 secondary dust collector flue gas outlet pipe, 27 chimney, 28 induced draft fan, 29 secondary dust collector ash pipe, 30 ash silo, 31 ash silo ash outlet, 32 ash silo ash outlet, 33 Circulating gray air chute, 34 digestion circulating fluidized bed flue gas desulfurization tower.

Detailed ways

Example 1

 As shown in Fig. 1 and Fig. 2, the digestive circulating fluidized bed flue gas desulfurization tower of the present invention comprises three sections: a pre-dusting section (lower section), a venturi section (middle section), and a digestion reaction section (upper section).

 The lower part of the desulfurization tower is a pre-dusting section 12, the side wall is provided with a flue gas inlet 1, the bottom part is provided with a ash discharge port, and the ash discharge valve is installed. 13. The flue gas inlet baffle 10 is arranged above the flue gas inlet of the pre-duster.

 The inner section of the desulfurization tower has an inner diameter of 4 meters. The middle part of the desulfurization tower, that is, the upper part of the pre-dusting section is the venturi section 2, and the interior is vertically arranged with 7 venturi tubes.

 The upper part of the desulfurization tower, that is, the upper part of the venturi tube bundle section 2 is the digestion reaction section 8, the side wall of the digestion reaction section 8, the venturi tube bundle section is provided with the desulfurization agent injection inlet 3, and the circulating ash injection inlet 14 (the desulfurization agent injection inlet 3) The circulating ash jet inlets 14 are respectively connected to the desulfurizing agent air chute 21 and the circulating ash air chute 34). A three-stage atomizing water spout is used, which is a digestive water nozzle 9, a humidifying water nozzle 4, and a replenishing water nozzle 5. Above the inner wall of the digestion reaction section 8, the desulfurizing agent injection port 3, and the circulating ash jet inlet 14, a digesting water nozzle 9 and a humidifying water nozzle 4 are sequentially disposed from the lower side, and a replenishing water nozzle 5 is disposed at the top of the digesting reaction section 8. A flue gas outlet is arranged on the upper side wall of the digestion reaction section, and a flue gas outlet baffle 6 is arranged above the flue gas outlet 7 in the digestion reaction section.

 The desulfurization tower is mounted on the bracket 11.

Example 2

A sintering plant has a flue gas volume of 2000 m ³ /h, a sulfur dioxide content of 700 mg/Nm ³ , and a flue gas temperature of 120 ° C. The flue gas desulfurization process of the present invention is used for desulfurization treatment, and the flue gas temperature of the secondary dust collector is 70 °C.

 The operational parameters of this embodiment are as follows:

 Desulfurizer consumption 2. 5kg / h

 Digested water consumption 2. 2kg/h

 Humidification water consumption 60kg/h

 Supplemental water consumption 2kg/h

 Ca/S (mol/mol) = l. 2

5kg/h After treatment, the sulfur dioxide content was 56 mg/Nm ³ and the desulfurization rate was 92%.

 The specific process engineering is as follows.

 The massive quicklime is sent to the mill 18 through the lump lime inlet 17, and is ground into a quicklime powder by the mill 18. After the classification treatment, the lime powder having a particle size of <0.048 mm is used (the lime quality requirement: CaO>80%, particle size< 0.048mm), sent to the ultra-fine lime powder silo 19, and sprayed into the desulfurization tower through the desulfurizer air chute 20 through the desulfurizer injection tank 3 by pneumatic conveying method, and the pressure of the conveying gas is controlled to 0.5 MPa.

 The clean process water is delivered by the high pressure pump through the digested water inlet 15, the humidified water inlet 16, the supplementary water inlet 21, the digested water nozzle 9 sent to the reaction section, the humidified water nozzle 4, and the supplementary water nozzle 5 are sprayed. In the desulfurization tower, the pressure for controlling the sprayed water was 1.0 MPa.

 The flue gas is introduced into the flue gas desulfurization tower 34 of the digestive circulating fluidized bed from the flue gas inlet 1 of the pre-dusting section, and the flue gas is removed by the pre-dusting section to reduce the load of the subsequent dedusting and purifying device, and at the same time increase the sulfur dioxide in the flue gas. The probability of collision with the desulfurizer is beneficial to desulfurization. The coarse dust is discharged from the ash discharge valve 13. After removing the large particle dust, the flue gas rises to the venturi tube bundle section 2, and enters the digestion reaction section at a high speed under the action of the venturi tube, and the flow state becomes intense turbulence, and the process water sprayed into the desulfurization tower, Desulfurization agent and circulating ash mass transfer and heat transfer. Under the conditions of digestion, humidification and cooling (desulfurization reaction temperature is 80 °C), slaked lime reacts with sulfur dioxide in the flue gas to form calcium sulfite, and some calcium sulfite is The air is oxidized to calcium sulfate, and the sulfur dioxide in the flue gas is removed. The flue gas after desulfurization is discharged from the flue gas outlet 7 at the upper portion of the tower, and enters the secondary dust collector 24 through the flue gas outlet pipe 22 and the secondary dust collector flue gas inlet 23.

The secondary dust collector 24 uses an electrostatic precipitator with a dust removal efficiency of more than 99%, and the ash silo 30 under the secondary dust collector ash discharge line 29 has two outlets, one is a ash silo circulating ash outlet 32, and the ash silo circulating ash outlet 32 The circulating ash air chute 33 is connected to the circulating ash jet inlet 14 of the desulfurization tower, and the pneumatic conveying method is used to control the pressure of the conveying gas to be 0.5 MPa, and the circulating ash is sprayed into the desulfurization tower, and the circulating ash is heated to 70 by the steam heating method. °C to facilitate delivery. The other outlet of the bottom ash silo is the ash silo outlet 31 through which the ash is discharged from the outer ash yard. Part of the circulating ash collected by the secondary dust collector 24 is adjusted by the amount of recirculating feed, maintaining the ash concentration of the secondary dust collector flue gas outlet to be 60 mg/in ³ , and the clean flue gas is discharged from the secondary dust collector flue gas outlet 25 into two. The stage dust collector flue gas outlet pipe 26 is discharged into the chimney 27 via the induced draft fan 28 and discharged into the atmosphere.

 In the process, the secondary atomization water spray quantity is mainly controlled, so that the exhaust gas temperature of the secondary dust collector is 70° 0. Control the smoke retention time to 2 seconds.

Example 3

A sintering plant has a flue gas volume of 10,000 m7h, a sulfur dioxide content of 800 mg/Nm ³ , and a flue gas temperature of 120 °C. The flue gas desulfurization process of the present invention is used for desulfurization treatment, and the secondary dust collector outlet flue gas temperature is 7 CTC.

The operational parameters of this embodiment are as follows: Desulfurizer consumption 12kg/h

 Digested water consumption l lkg/h

 Humidification water consumption 320kg/h

 Supplemental water consumption 10kg/h

 Ca/S (mol/mol) =1. 3

 Circulating ash return volume 25kg/h

After the treatment, the sulfur dioxide content was 40 mg/Nm ³ and the desulfurization rate was 95%.

 The specific process is as follows.

 The block-shaped quicklime with a particle size of 80 mm is ground into a quicklime powder by a mill, and the chunks of quicklime are ground into a quicklime powder by a mill. After the classification, lime powder having a particle size of <0.0480101 is used (lime quality requirement: CaO>80%, particle size) <0.048mm), sent to the lime silo, sprayed into the desulfurization tower through the desulfurizer injection port by pneumatic conveying method, and the pressure of the conveying gas is controlled to 0.4MPa.

 The clean process water is sprayed into the desulfurization tower through the digesting water nozzle, the humidifying water nozzle and the supplementary water nozzle of the reaction section by a high-pressure pump, and the pressure of the injected water is controlled to 2.0 MPa.

 The flue gas is introduced into the desulfurization tower from the flue gas inlet of the pre-dusting section, and the flue gas is removed from the pre-dusting section to reduce the load of the subsequent dedusting and purifying device, and at the same time increase the collision probability of the sulfur dioxide and the desulfurizing agent in the flue gas, which is beneficial to the flue gas. Desulfurization. After removing the large particle dust, the flue gas rises to the venturi section, and enters the digestion reaction section at high speed under the action of the venturi tube. The flow state becomes intense turbulence, and the process water and desulfurization sprayed into the desulfurization tower. The agent and the circulating ash mass transfer and heat transfer. Under the conditions of digestion, humidification and cooling (the desulfurization reaction temperature is 75 °C), the slaked lime reacts with the sulfur dioxide in the flue gas to form calcium sulfite, and some calcium sulfite is air. Oxidation to calcium sulfate, sulfur dioxide in the flue gas is removed. The purified flue gas is discharged from the flue gas outlet at the upper part of the tower and enters the secondary dust collector through the flue gas duct.

The secondary dust collector adopts a bag type dust remover with a dust removal efficiency of more than 99%, and there are two outlets of the bottom ash bin. One circulating ash outlet is connected to the circulating ash jet inlet of the desulfurization tower through a pipeline, and the conveying gas is controlled by a pneumatic conveying method. The pressure is 0.2 MPa, and the circulating ash is sprayed into the desulfurization tower, and the circulating ash is heated to 65 ° C by steam to facilitate transportation. The other outlet of the bottom ash silo is the ash outlet, through which the ash is discharged out of the ash yard. Part of the circulating ash collected by the secondary dust collector is adjusted by the amount of recirculating feed, and the ash concentration of the flue gas outlet of the secondary dust collector is kept at 70 mg/m ³ , and the clean flue gas is discharged into the chimney through the induced draft fan and discharged into the atmosphere.

 In the process, the secondary atomization water spray quantity is mainly controlled, so that the secondary dust collector outlet flue gas temperature can be 5570 ° C. Control the smoke retention time to 1. 5 seconds.

Example 4

A sintering plant has a flue gas volume of 200,000 m ³ /h, a sulfur dioxide content of 600 mg/Nm ³ , and a flue gas temperature of 120 ° C. Using the invention The flue gas desulfurization process is subjected to desulfurization treatment, and the flue gas temperature of the precipitator outlet is 70 °C.

 The desulfurization agent monocalcium oxide powder used in this embodiment is prepared into a lime silo by using a vertical medium speed mill at the site, and other operating parameters are as follows:

 Desulfurizer consumption 240kg/h

 Digested water consumption 220kg/h

 Humidification water consumption 6000kg/h

 Supplemental water consumption 200kg/h

 Ca/S (mol/mol) =1. 1

 Circulating ash return amount 500kg/h

After the treatment, the sulfur dioxide content is 60 mg/Nm ³ and the desulfurization rate is 90%.

 The specific process engineering is as follows.

 The block-shaped quicklime with a particle size of 80 mm is ground into a quicklime powder by a mill, and the chunks of quicklime are ground into a quicklime powder by a mill. After the classification, lime powder having a particle size of <0.0480101 is used (lime quality requirement: CaO>80%, particle size) <0.048mm), sent to the lime silo, sprayed into the desulfurization tower through the desulfurizer injection port by pneumatic conveying method, and the pressure of the conveying gas is controlled to 0.5MPa.

 The clean process water is sprayed into the desulfurization tower through the digesting water nozzle, the humidifying water nozzle and the supplementary water nozzle of the reaction section by a high-pressure pump, and the pressure of the sprayed water is controlled to be 2.5 MPa.

 The flue gas is introduced into the desulfurization tower from the flue gas inlet of the pre-dusting section, and the flue gas is removed from the pre-dusting section to reduce the load of the subsequent dedusting and purifying device, and at the same time increase the collision probability of the sulfur dioxide and the desulfurizing agent in the flue gas, which is beneficial to the flue gas. Desulfurization. After removing the large particle dust, the flue gas rises to the venturi section, and enters the digestion reaction section at high speed under the action of the venturi tube. The flow state becomes intense turbulence, and the process water and desulfurization sprayed into the desulfurization tower. The agent and the circulating ash mass transfer and heat transfer. Under the conditions of digestion, humidification and cooling (desulfurization reaction temperature is 90 °C), the slaked lime reacts with sulfur dioxide in the flue gas to form calcium sulfite, and some calcium sulfite is air. Oxidation to calcium sulfate, sulfur dioxide in the flue gas is removed. The purified flue gas is discharged from the flue gas outlet at the upper part of the tower and enters the secondary dust collector through the flue gas duct.

The secondary dust collector adopts an electrostatic precipitator with a dust removal efficiency of more than 99%. There are two outlets at the bottom of the ash silo. One circulating ash outlet is connected to the circulating ash jet inlet of the desulfurization tower through a pipeline, and the pneumatic conveying method is used to control the conveying gas. The pressure is 1.0 MPa, and the circulating ash is sprayed into the desulfurization tower, and the circulating ash is heated to 90 ° C by steam to facilitate transportation. The other outlet of the bottom ash silo is the ash outlet, through which the ash is discharged out of the ash yard. Part of the circulating ash collected by the secondary dust collector is adjusted by the amount of recirculating feed, and the ash concentration of the flue gas outlet of the secondary dust collector is kept at 56 mg/m ³ , and the clean flue gas is discharged into the chimney through the induced draft fan and discharged into the atmosphere.

 In the process, the secondary atomizing water spray flow is mainly controlled, so that the secondary dust collector outlet flue gas temperature is 70. Control the smoke retention time to 3 seconds.

Claims

 Autumn ^Ka, a digestive circulating fluidized bed flue gas desulfurization device, including a mill, a desulfurization tower and a bag filter, characterized in that the device desulfurization tower is divided into three sections: a pre-dusting section (12), a venturi section (2) and the digestion reaction section (8), the lower part is the pre-dusting section (12), the upper part of the pre-dusting section is the venturi section (2), the inner longitudinal direction is closely arranged with the venturi tube, and the venturi section The upper part of (2) is the digestion reaction section (8), the side wall of the digestion reaction section (8), the venturi tube bundle section (2) is provided with a desulfurizing agent injection inlet (3), and the circulating ash injection inlet (14), in the digestion The inner wall of the reaction section (8), the desulfurizing agent injection inlet (3), and the circulating ash injection inlet (14) are provided with a digesting water nozzle (9) and a humidifying water nozzle (4) in order from the bottom to the top, in the digestion reaction section. (8) The top of the inner part is provided with a makeup water nozzle (5).  2. A digestive circulating fluidized bed flue gas desulfurization apparatus according to claim 1, characterized in that a flue gas inlet deflector (10) is arranged above the flue gas inlet in the pre-dusting section (12).  A digestive circulating fluidized bed flue gas desulfurization apparatus according to claim 1, wherein a flue gas outlet deflector (6) is disposed above the flue gas outlet in the digestion reaction section (8).  A method for treating flue gas by using the digestive-circulating fluidized bed flue gas desulfurization apparatus according to claim 1, wherein the treatment process is:  The block-shaped quicklime is ground into quicklime powder, and after being classified, the lime powder having a particle size of <0.048 mm is sent to the lime silo, and is sprayed into the desulfurization tower through the desulfurizing agent injection port by pneumatic conveying method;  The clean process water is sent by a high-pressure pump to the desulfurization tower through a digesting water nozzle, a humidifying water nozzle and a supplementary water nozzle of the reaction section of the flue gas desulfurization device of the digestion circulating fluidized bed;  The flue gas is introduced into the flue gas desulfurization device of the digestive circulating fluidized bed from the flue gas inlet of the pre-dusting section, the flue gas and the process water sprayed into the desulfurization tower, the desulfurizer and the circulating ash mass transfer, heat transfer, in the digestion and increase Desulfurization reaction is carried out under wet and cool conditions, and the flue gas after desulfurization is discharged from the flue gas outlet at the upper part of the tower, and enters the secondary dust remover through the flue gas pipeline;  In the pneumatic conveying method, the circulating ash collected by the secondary dust collector is sprayed into the desulfurization tower, and the remaining ash is discharged from the outer ash outlet, and the clean flue gas is discharged into the chimney through the induced draft fan and discharged into the atmosphere.  5. The method according to claim 4, characterized in that the temperature of the desulfurization reaction is controlled to be 75 to 90 ° C, mainly by controlling the flow rate of the secondary atomizing water spray, so that the temperature of the outlet of the secondary dust collector is 70 ° C, and is controlled. The Ca/S molar ratio is 1.0 to 1. 6. The control flue gas residence time is 1 to 3 seconds.  6. A method according to claim 4, characterized in that the mass of lime used as a desulfurizing agent is: CaO > 80%, particle size < 0.048 mm.  A method according to claim 4, wherein the gas pressure for controlling the transport of the lime powder is 0.2 to 1.0 MPa, and the pressure for controlling the sprayed water is 0.1 to 2.5 MPa.  8. A method according to claim 4, characterized in that the primary atomizing spray water is passed through a compressed air of 0.1 to 0.5 MPa, and the tertiary atomizing water spray is passed through a cleaned flue gas of 0.1 to 0.5 MPa.  9. A method according to claim 4, characterized in that the circulating ash is heated to 60 to 90 °C.