CN112058050A

CN112058050A - Desulfurization and denitrification system device and method adopting ozone oxidation and semidry method

Info

Publication number: CN112058050A
Application number: CN202010976226.0A
Authority: CN
Inventors: 杨森林; 刘勇; 胡小吐; 钟璐; 胡静龄; 杨颖欣
Original assignee: Guangdong Jiade Environmental Protection Technology Co Ltd
Current assignee: Guangdong Jiade Environmental Protection Technology Co Ltd
Priority date: 2020-09-16
Filing date: 2020-09-16
Publication date: 2020-12-11

Abstract

The invention provides a desulfurization and denitrification system device and a desulfurization and denitrification method based on an ozone oxidation synergistic semidry method, wherein the desulfurization and denitrification system device comprises an ozone oxidation unit, an absorbent feeding unit, a fluidized bed reaction unit and a separation and dust removal unit; the ozone oxidation unit and the absorbent feeding unit are respectively and independently connected into the fluidized bed reaction unit, and the fluidized bed reaction unit is circularly connected with the separation and dust removal unit. The desulfurization and denitrification system device provided by the invention is reasonable in configuration, is combined with ozone oxidation, realizes synchronous desulfurization and denitrification, ensures that the absorbent obtains high circulation rate and utilization rate, does not have the problems of wall adhesion, scaling and bed collapse, obviously reduces the dust content of the outlet flue gas, greatly lightens the load of a rear dust removal device, ensures that the device runs safely, stably and for a long period, and effectively solves the technical problem in the semi-dry flue gas desulfurization technology.

Description

Desulfurization and denitrification system device and method adopting ozone oxidation and semidry method

Technical Field

The invention belongs to the technical field of flue gas desulfurization and denitration, and relates to a desulfurization and denitration system device and a method, in particular to a desulfurization and denitration system device and a method adopting an ozone oxidation and semi-dry method.

Background

The circulating fluidized bed flue gas desulfurization system mainly comprises the following systems: (1) absorbent storage, dry digestion and transport; (2) smoke atomization, humidification and temperature regulation; (3) the desulfurizer fully contacts and mixes with the wet flue gas containing atomized particles; (4) absorbing sulfur dioxide; (5) humidifying and activating; (6) circulating ash; (7) and (5) removing waste residues. The method adopts a circulating fluidized bed as a principle, and through the internal circulation of materials in the bed and the external circulation with high multiplying power, the heat and mass transfer exchange between the absorbent and SO2 is strong, the mass transfer process in the absorbent is strong, the retention time of solid materials in the bed is as long as 30-60 minutes, and the operation temperature can be reduced to be close to the dew point, SO that the utilization rate and the desulfurization rate of the absorbent are greatly improved. Under the condition of a low Ca/S ratio (Ca/S is 1.1-1.3), the desulfurization rate can be comparable to that of a limestone wet process, namely, the desulfurization rate is more than 90%. The specific semi-dry desulfurization principle of the circulating fluidized bed (taking Yiteng environmental protection as an example) is as follows:

through the multiple recirculation of the absorbent, the contact time of the absorbent and the flue gas is prolonged in the desulfurizing tower, so that the aim of high-efficiency desulfurization is fulfilled, and meanwhile, the utilization rate of the absorbent is greatly improved. Through chemical reaction, the acidic gases such as SO2, SO3, HF and HCl in the flue gas can be effectively removed, and the desulfurization end product desulfurization slag is a free-flowing dry powder mixture, has no secondary pollution and can be further comprehensively utilized. The process is mainly applied to the flue gas desulfurization of power station boilers, and the flue gas treatment capacity of a single tower can be suitable for boilers with the evaporation capacity of 75 t/h-1025 t/h, namely SO₂The removal rate can reach 90-98%, and the method is the method with the largest single-tower processing capacity and the highest comprehensive desulfurization benefit in the prior dry-method and semi-dry-method desulfurization technologies and the like.

CN208032310U discloses a semi-dry desulfurization ash-removing system, which comprises an absorption tower system, a dust-removing system, an ash conveying system and an ash-removing system, wherein the ash-removing system comprises an ash bin and a bin pump; the absorption tower system comprises a desulfurizer feeding pool and a semi-dry desulfurization absorption tower, the dust removal system comprises a pre-dust remover and a bag-type dust remover, and the ash conveying system comprises a desulfurizer conveying device and a circulating ash conveying device; the desulfurizer feeding tank is connected with an inlet of the pre-deduster, an outlet of the pre-deduster is connected with an inlet of the desulfurizer conveying device, and an outlet of the desulfurizer conveying device is connected with the lower part of the semi-dry desulfurization absorption tower; the upper part of the semi-dry desulfurization absorption tower is connected with an inlet of a bag-type dust remover, the bottom of the semi-dry desulfurization absorption tower is connected with an inlet of an ash bin, an outlet of the bag-type dust remover is connected with an inlet of a circulating ash conveying device, and an outlet of the circulating ash conveying device is connected to the lower part of the semi-dry desulfurization absorption tower; the ash bin is connected with the desulfurizer conveying device through a bin pump.

CN101066523A discloses a semi-dry desulfurization process of a double-feed-back circulating fluidized bed, which relates to the improvement of a desulfurization and purification process of coal-fired flue gas; the process comprises the following steps: a. the method comprises the following steps that flue gas enters a dust remover for pre-dedusting, 70-80% of fly ash in the flue gas is directly separated, the flue gas is sent to a reaction tower for desulfurization after the pre-dedusting of the dust remover, and the flue gas desulfurized from the reaction tower is dedusted by the dust remover and discharged by a draught fan and a chimney; b. part of the purified flue gas is recycled and is merged with the flue gas subjected to pre-dedusting and sent into a reaction tower; c. the desulfurized ash can be sent to the reaction tower through a fan; d. one part of the flue gas is separated by the cyclone separator and is sent back to the bottom inlet of the dust remover, and the fly ash is sent into the hopper and the reaction tower through the feeder.

CN104941435A discloses a flue gas desulfurization method for a normal-temperature semi-dry circulating fluidized bed, which adopts a desulfurization system comprising a circulating fluidized bed reactor and a desulfurizer slurry preparation and conveying system; the circulating fluidized bed reactor comprises a riser, a cyclone separator, a circulating material feeding device and a nozzle; the desulfurizer slurry preparation and conveying system comprises a quicklime bin, a metering control device, a slurry making pool, a water adding pipe, a slurry filter and a slurry pump; the quick lime bin is sequentially connected with the metering control device, the pulping pool, the slurry filter (8), the slurry pump and the nozzle, the nozzle is arranged in the dense-phase region of the ascending pipe, and the material outlet of the circulating material adding device (3) is connected with the ascending pipe.

However, the problem of wall-hanging scaling can occur in the existing semidry process, so that the system can not work normally, and the removal rate of nitrogen oxides in the flue gas is low.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a platform gate control system and a platform gate control method, the desulfurization and denitrification system device provided by the invention is reasonable in configuration and combined with ozone oxidation, the synchronous proceeding of desulfurization and denitrification is realized, the high circulation rate and the utilization rate of an absorbent are obtained, the problems of wall adhesion, scaling and bed collapse are avoided, the dust content of outlet flue gas is obviously reduced, the load of a rear dust removal device is greatly reduced, the safe, stable and long-period operation of the device is ensured, and the technical problem in the semi-dry flue gas desulfurization technology is effectively solved.

In order to achieve the purpose, the invention adopts the following technical scheme:

in a first aspect, the invention provides a desulfurization and denitrification system device adopting an ozone oxidation and semidry method, which comprises an ozone oxidation unit, an absorbent feeding unit, a fluidized bed reaction unit and a separation and dust removal unit;

the ozone oxidation unit and the absorbent feeding unit are respectively and independently connected into the fluidized bed reaction unit, and the fluidized bed reaction unit is circularly connected with the separation and dust removal unit.

The desulfurization and denitrification system device provided by the invention is reasonable in configuration, is combined with ozone oxidation, realizes synchronous desulfurization and denitrification, ensures that the absorbent obtains high circulation rate and utilization rate, does not have the problems of wall adhesion, scaling and bed collapse, obviously reduces the dust content of the outlet flue gas, greatly lightens the load of a rear dust removal device, ensures that the device runs safely, stably and for a long period, and effectively solves the technical problem in the semi-dry flue gas desulfurization technology.

As a preferable technical scheme of the invention, the fluidized bed reaction unit comprises a fluidized bed reaction device.

Preferably, the fluidized bed reaction device comprises a shell, an inner cylinder with two open ends is coaxially arranged below the inside of the shell, and an annular cavity is reserved between the shell and the inner cylinder; the inner wall of the shell is provided with a first air inlet point position, and the inner wall of the inner barrel is provided with a second air inlet point position.

Preferably, the outlet end of the air inlet flue of the fluidized bed reaction device is divided into two paths, the two paths are respectively connected with the first air inlet point position and the second air inlet point position, the flue gas is divided into first flue gas and second flue gas, the first flue gas and the second flue gas respectively enter the fluidized bed reaction device, the first flue gas enters the annular cavity through the first air inlet point position in the tangential direction, the second flue gas enters the inner cylinder through the second air inlet point position in the tangential direction, and the tangential air inlet directions of the first flue gas and the second flue gas are opposite.

In the invention, the inner cylinder is arranged, so that the first flue gas flow and the second flue gas flow can be separated below the fluidized bed reaction device, and the two flue gas flows are mixed above the inner cylinder in an opposite rotational flow state. The first flue gas flow can prevent the inner wall surface of the shell from accumulating dust and promote the mixing of the air flow ascending from the bottom

Preferably, the inner cylinder is internally provided with a slurry absorbing nozzle close to the smoke inlet end.

Preferably, at least one ozone spraying layer, at least one oxidant spraying layer and one absorption slurry spraying layer are arranged above the inner cylinder along the flow direction of the flue gas, and the oxidant spraying layers are respectively and independently connected with an oxidant storage tank externally.

Preferably, the ozone spraying layer and the oxidant spraying layer are alternately distributed.

Preferably, the ozone injection layer comprises an annular injection main pipe and a nozzle arranged on the annular injection main pipe;

preferably, the oxidant sprays the layer and includes that the annular sprays the main pipe and sets up the shower nozzle on the annular sprays the main pipe.

NO in the flue gas can be sprayed on the one hand by arranging the oxidant spraying layer_xDeep oxidation is carried out, and simultaneously, the oxidation can be further carried outThe flue gas is cooled to achieve the aim of controlling the temperature of the flue gas. In fluidized bed reactors, flue gas temperature control is extremely important because: (1) limestone absorption of SO in flue gas₂The capacity of the flue gas is improved along with the reduction of the temperature of the flue gas; on the other hand, however, too low a flue gas temperature increases the viscosity of the circulating material in the fluidized-bed reactor. According to the invention, the annular spraying main pipe is arranged, the oxidant is sprayed to the inner wall surface of the fluidized bed reaction device, a high-strength turbulent flow zone is formed on the inner wall surface of the fluidized bed reaction device, the aggregation of absorption slurry particles near the inner wall of the tower body is reduced, the wall-sticking scaling phenomenon is reduced, the system operation stability is improved, and meanwhile, the absorbent particles near the wall surface can enter the central area in the tower to be efficiently utilized.

Preferably, a first oxidant spraying layer, a first ozone spraying layer, a second oxidant spraying layer, a second ozone spraying layer and an absorption slurry spraying layer are arranged above the inner cylinder along the flow direction of the flue gas. .

As a preferable technical scheme of the invention, the ozone oxidation unit comprises a mixing device and an ozone generating device, the mixing device is connected to the inlet flue, the ozone generating device is connected to the inlet flue through an ozone injection pipeline, flue gas is contacted with ozone input by the ozone generating device after entering the inlet flue, and then enters the mixing device to be uniformly mixed and fully oxidized.

Preferably, the outlet end of the ozone injection pipeline extends into the inlet flue.

Preferably, the outlet end of the ozone injection pipeline is provided with an ozone injection device.

Preferably, the spraying direction of the ozone spraying device is opposite to the flow direction of the flue gas.

Preferably, the ozone generating devices are respectively and independently connected with the ozone spraying layer.

As a preferable technical scheme of the invention, the absorbent feeding unit comprises an absorbent bin, a stirring device and a buffer tank which are sequentially connected along a feeding direction.

Preferably, the absorbent feeding unit further comprises a process water storage tank and a conveying device, the process water storage tank is respectively and independently connected to the stirring device and the buffer tank, and the absorbent bin is in butt joint with the stirring device through the conveying device.

Preferably, the buffer tank is respectively and independently connected with the absorption slurry nozzle and the absorption slurry spraying layer.

As a preferable technical scheme of the invention, the separation and dust removal unit is a separation device and a dust removal device which are sequentially connected along the smoke discharge direction.

Preferably, a discharge port at the bottom of the separation device is connected to the absorption slurry nozzle through a return pipeline, and the desulfurized fly ash separated by the separation device is sprayed into the fluidized bed reaction device through the return pipeline and the absorption slurry nozzle.

Preferably, a steam activation device is arranged on the feed back pipeline, and the steam activation device is externally connected with a steam pipeline.

The steam activation device is arranged on the material return pipeline, the residual absorbent in the desulfurized fly ash is physically adsorbed with water vapor and chemically reacted with water molecules to further excite and improve the sulfur fixing capacity of the desulfurized fly ash, the physical and chemical properties of the absorbent particles are changed after the steam activation, and the reaction product layer formed on the surfaces of the particles is further crushed to expose the unreacted fresh absorbent component inside the particles. In addition, under the action of steam, the absorbent and SiO in the desulfurized fly ash₂Or Al₂O₃The mixing reaction also forms calcium-containing sol-gel particles with strong desulfurization activity. Thereby further enhancing the sulfur fixation activity of the absorbent and obtaining maximum utilization through further residual desulfurization reaction in the process of repeated circulation of materials in the bed; meanwhile, the flue gas desulfurization efficiency is further improved. In addition, because the steam is supplied, the fluidized bed reaction device has no liquid water and is always kept dry, and acid corrosion does not exist. After the activation treatment, the temperature change of the suspension fluidized bed layer is small, so that additional heat loss caused by cooling flue gas and the suspension fluidized bed layer does not exist.

Preferably, the bottom discharge port of the dust removal device is connected to the return pipe, and the desulfurized fly ash collected at the bottom of the dust removal device and the desulfurized fly ash collected at the bottom of the separation device are mixed and then flow into the steam activation device through the return pipe.

Preferably, the outlet end of the dust removal device is connected with a chimney.

In a second aspect, the invention provides a desulfurization and denitrification method by ozone oxidation in cooperation with a semi-dry method, wherein the desulfurization and denitrification system device of the first aspect is adopted to perform desulfurization and denitrification on flue gas; the desulfurization and denitrification method comprises the following steps:

the flue gas is introduced into the fluidized bed reaction unit after being subjected to contact oxidation by the ozone oxidation unit and ozone, the absorbent feeding unit sprays absorption slurry to the fluidized bed reaction unit to absorb slurry particles to form a suspension fluidized bed, the oxidized flue gas passes through the suspension fluidized bed to be subjected to desulfurization and denitrification, and the flue gas after desulfurization and denitrification is discharged to enter the separation dust removal unit to be separated to obtain desulfurization ash in the flue gas to be returned to the fluidized bed reaction unit for recycling.

As a preferred technical solution of the present invention, the desulfurization and denitrification method specifically includes:

the method comprises the following steps that (I) flue gas is introduced into an inlet flue to contact with ozone and then is mixed and oxidized, the oxidized flue gas is divided into first flue gas and second flue gas, the first flue gas and the second flue gas are introduced into an annular cavity and an inner cylinder respectively by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in a fluidized bed reaction device;

(II) mixing and stirring an absorbent and process water in a stirring device to obtain absorbent thick slurry, diluting the absorbent thick slurry with the process water in a buffer tank to obtain absorption slurry, respectively spraying the absorption slurry into a fluidized bed reaction device through an absorption slurry nozzle and an absorption slurry spraying layer, forming a suspended fluidized bed layer in the fluidized bed reaction device by the absorption slurry, and respectively spraying ozone and an oxidant into the suspended fluidized bed layer through an ozone spraying layer and an oxidant spraying layer by an ozone generating device and an oxidant storage tank;

(III) the first flue gas and the second flue gas pass through a suspension fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device, the desulfurized ash in the flue gas is obtained through separation, and the flue gas after the desulfurized ash is removed is emptied after dedusting; the desulfurized ash collected by the separation device and the desulfurized ash recovered after the flue gas is dedusted are mixed and then fall into a steam activation device to be contacted with steam, and the mixture is returned to the fluidized bed reaction device for cyclic utilization after being activated.

The absorbent bin and the process water storage tank respectively convey quicklime and process water into the stirring device, absorption slurry is generated through reaction in the stirring process, the absorption slurry is sprayed into hot flue gas by utilizing the spray drying principle, after the process water is atomized into water drops and enters the fluidized bed reaction device, a part of water drops capture calcium hydroxide particles to form slurry drops, the evaporation speed of water in the slurry drops is reduced, the desulfurization reaction in the initial stage of the slurry drops is an ionic reaction, the desulfurization reaction gradually transits from the ionic reaction to a gas-solid reaction along with the evaporation of water, the water drops without the absorbent slurry drops are quickly evaporated in the flue gas, the temperature of the flue gas is reduced, the effective volume of the cooled flue gas is reduced, and SO removal is also realized₂And dust removal is more effective.

The reaction steps are as follows:

(1) SO in flue gas₂Absorption of sprayed process water droplets: SO (SO)₂+H₂O→H₂SO₃；

(2) Absorbed SO₂Reaction with absorbent slurry particles: ca (OH)₂+H₂SO₃→CaSO₃+2H₂O；

(3) CaSO in liquid droplets₃Crystallizing and separating out after saturation is achieved;

(4) CaSO in partial solution₃Reacting with oxygen in the solution to oxidize into calcium sulfate;

(5)CaSO₄low solubility and crystallization.

In a preferred embodiment of the present invention, in step (I), the mass flow rate of ozone sprayed into the inlet flue by the ozone generator is 2 to 10kg/h, for example, 2kg/h, 3kg/h, 4kg/h, 5kg/h, 6kg/h, 7kg/h, 8kg/h, 9kg/h or 10kg/h, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the ozone generating device sprays ozone and NO in the flue gas into the inlet flue_xThe molar ratio of (1: 0.8) to (0.80: 1) may be, for example, 0.82:1, 0.84:1, 0.86:1, 0.88:1, 0.9:1, 0.92:1, 0.94:1, 0.96:1, 0.98:1 or 1:1, but is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned range are also applicable.

Preferably, the contact time of the flue gas and ozone in the mixing device is 0.5 to 1.5s, for example 0.5s, 0.6s, 0.7s, 0.8s, 0.9s, 1.0s, 1.1s, 1.2s, 1.3s, 1.4s or 1.5s, but not limited to the values listed, and other values not listed in this range of values are equally applicable.

Preferably, the volumetric flow ratio of the first flue gas to the second flue gas is (2-3): 1, and may be, for example, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1, 2.7:1, 2.8:1, 2.9:1, or 3.0:1, but is not limited to the recited values, and other values not recited within this range of values are equally applicable.

In a preferred embodiment of the present invention, in step (ii), the absorbent is calcium oxide.

Preferably, the particle size of the calcium oxide is 1 to 100mm, and may be, for example, 1mm, 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm, 80mm, 90mm or 100mm, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the calcium oxide is mixed with the process water and stirred to obtain a concentrated calcium hydroxide slurry with a solid content of 40-50%, for example, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49% or 50%, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the molar ratio of calcium oxide to process water is (5-20): 1, and may be, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1 or 20:1, but is not limited to the recited values, and other values not recited within the range of values are equally applicable.

Preferably, the quicklime and the process water are mixed, stirred and then left standing for 5-30 min, such as 5min, 6min, 7min, 8min, 9min, 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min, 20min, 21min, 22min, 23min, 24min, 25min, 26min, 27min, 28min, 29min or 30min, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the calcium hydroxide slurry is diluted with process water to obtain a calcium hydroxide slurry with a solid content of 20-30%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, but not limited to the recited values, and other values not recited in the range of the recited values are also applicable.

Preferably, the molar ratio of Ca in the calcium hydroxide slurry to the sulfur nitrate in the flue gas is (1-2): 1, and may be, for example, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, or 2.0:1, but is not limited to the recited values, and other values not recited in the range of values are equally applicable.

Preferably, the mass flow of ozone introduced into each ozone injection layer by the ozone generating device is gradually reduced along the flow direction of the flue gas.

Preferably, the mass flow rate of ozone introduced into each ozone injection layer by the ozone generating device is gradually reduced along the flow direction of the flue gas according to a reduction ratio of 20-30%, for example, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29% or 30%, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the ozone generator injects ozone into the first ozone injection layer at a mass flow rate of 2 to 10kg/h, such as 2kg/h, 3kg/h, 4kg/h, 5kg/h, 6kg/h, 7kg/h, 8kg/h, 9kg/h or 10kg/h, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the molar ratio of the ozone sprayed by the first ozone spraying layer to the NO in the flue gas is (0.8-1): 1, and may be, for example, 0.8:1, 0.81:1, 0.82:1, 0.83:1, 0.84:1, 0.85:1, 0.86:1, 0.87:1, 0.88:1, 0.89:1, 0.9:1 or 1:1, but is not limited to the enumerated values, and other non-enumerated values within the numerical range are also applicable.

Preferably, the ozone generator injects ozone into the second ozone injection layer at a mass flow rate of 1.5-8 kg/h, such as 1.5kg/h, 2kg/h, 2.5kg/h, 3kg/h, 3.5kg/h, 4kg/h, 4.5kg/h, 5kg/h, 5.5kg/h, 6kg/h, 6.5kg/h, 7kg/h, 7.5kg/h or 8kg/h, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the molar ratio of the ozone sprayed by the second ozone spraying layer to the NO in the flue gas is (0.5-0.8): 1, and may be, for example, 0.5:1, 0.55:1, 0.6:1, 0.65:1, 0.7:1, 0.75:1 or 0.8:1, but is not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the oxidant is sodium chlorite solution.

Preferably, the pH of the oxidizing agent is 3 to 6, for example, 3, 4, 5 or 6, but not limited to the recited values, and other values not recited within the range of values are also applicable.

Preferably, the oxidant and NO in the flue gas_xThe molar ratio of (1 to 2):1 may be, for example, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2.0:1, but is not limited to the enumerated values, and other values not enumerated within the numerical range are also applicable.

Preferably, the reaction temperature in the fluidized bed reactor is 160 to 180 ℃, for example 160 ℃, 162 ℃, 164 ℃, 166 ℃, 168 ℃, 170 ℃, 172 ℃, 174 ℃, 176 ℃, 178 ℃ or 180 ℃, but not limited to the values listed, and other values not listed in the range of the values are also applicable.

Preferably, the residence time of the flue gas in the fluidized bed reactor is 3 to 8s, for example 3s, 4s, 5s, 6s, 7s or 8s, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

Preferably, the flow rate of the flue gas in the fluidized bed reactor is 15-20 m/s, such as 15m/s, 16m/s, 17m/s, 18m/s, 19m/s or 20m/s, but not limited to the values listed, and other values not listed in the range of values are equally applicable.

In a preferred embodiment of the present invention, in the step (iii), the separation device separates and collects 80 to 90% of the desulfurized fly ash in the flue gas, and the separated and collected desulfurized fly ash may be, for example, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, or 90%, and the dust removal device recovers the remaining desulfurized fly ash in the flue gas.

Preferably, the steam is 1.5-3 kg/cm²The pressure of (2) is introduced into the steam activation apparatus, and may be, for example, 1.5kg/cm²、1.6kg/cm²、1.7kg/cm²、1.8kg/cm²、1.9kg/cm²、2.0kg/cm²、2.1kg/cm²、2.2kg/cm²、2.3kg/cm²、2.4kg/cm²、2.5kg/cm²、2.6kg/cm²、2.7kg/cm²、2.8kg/cm²、2.9kg/cm²Or 3.0kg/cm²However, the numerical values recited are not intended to be limiting, and other numerical values not recited within the numerical range may be equally applicable.

Preferably, the steam temperature is 50 to 60 ℃, for example, 50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃ or 60 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

The system refers to an equipment system, or a production equipment.

Compared with the prior art, the invention has the beneficial effects that:

Drawings

Fig. 1 is a schematic structural diagram of a desulfurization and denitrification system apparatus according to an embodiment of the present invention.

Wherein, 1-an absorbent silo; 2-a conveying device; 3-a process water storage tank; 4-a stirring device; 5-a buffer tank; 6-an ozone generating device; 7-a mixing device; 8-a fluidized bed reaction unit; 9-inner cylinder; 10-first air intake site; 11-a second air intake site; 12-an absorption slurry nozzle; 13-a first oxidant spray layer; 14-a first ozone sparging layer; 15-a second oxidant spray layer; 16-a second ozone sparging layer; 17-absorbing the slurry spray layer; 18-an oxidant reservoir; 19-a separation device; 20-a steam activation device; 21-a dust removal device; 22-chimney.

Detailed Description

It is to be understood that in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are used only for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be taken as limiting the present invention. Furthermore, the terms "first", "second", etc. are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first," "second," etc. may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

It should be noted that, in the description of the present invention, unless otherwise explicitly specified or limited, the terms "disposed," "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art through specific situations.

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In one embodiment, the invention provides a desulfurization and denitrification system device adopting an ozone oxidation and semidry method, which is shown in fig. 1 and comprises an ozone oxidation unit, an absorbent feeding unit, a fluidized bed reaction unit and a separation and dust removal unit. The ozone oxidation unit and the absorbent feeding unit are respectively and independently connected to the fluidized bed reaction unit, and the fluidized bed reaction unit is circularly connected with the separation and dust removal unit.

The fluidized bed reaction unit comprises a fluidized bed reaction device 8, the fluidized bed reaction device 8 comprises a shell, an inner cylinder 9 with two open ends is coaxially arranged below the inside of the shell, and an annular cavity is reserved between the shell and the inner cylinder 9. The inner wall of the shell is provided with a first air inlet point position 10, and the inner wall of the inner cylinder 9 is provided with a second air inlet point position 11. The outlet end of an air inlet flue of the fluidized bed reaction device 8 is divided into two paths and is respectively connected with a first air inlet point position 10 and a second air inlet point position 11, the flue gas is divided into first flue gas and second flue gas which respectively enter the fluidized bed reaction device 8, the first flue gas enters the annular cavity through the first air inlet point position 10 in the tangential direction, the second flue gas enters the inner barrel 9 through the second air inlet point position 11 in the tangential direction, and the tangential air inlet directions of the first flue gas and the second flue gas are opposite. The inner cylinder 9 is provided with a slurry absorbing nozzle 12 inside and close to the smoke inlet end. At least one ozone spraying layer, at least one oxidant spraying layer and one absorbing slurry spraying layer 17 are arranged above the inner cylinder 9 along the flow direction of the flue gas, the ozone spraying layer and the oxidant spraying layer are alternately distributed, and the oxidant spraying layers are respectively and independently connected with an oxidant storage tank 18 externally. Specifically, a first oxidant spraying layer 13, a first ozone spraying layer 14, a second oxidant spraying layer 15, a second ozone spraying layer 16 and an absorption slurry spraying layer 17 are arranged above the inner cylinder 9 along the flow direction of the flue gas. The first ozone spraying layer 14 and the second ozone spraying layer 16 each include an annular spraying main pipe and a nozzle provided on the annular spraying main pipe. The first oxidant sprays layer 13 and the second oxidant sprays layer 15 and all includes that the annular sprays the person in charge and sets up the shower nozzle on the person in charge that sprays in the annular.

The ozone oxidation unit comprises a mixing device 7 and an ozone generating device 6, the mixing device 7 is connected into an inlet flue, the ozone generating device 6 is connected into the inlet flue through an ozone injection pipeline, flue gas is contacted with ozone input by the ozone generating device 6 after entering the inlet flue, and then enters the mixing device 7 to be uniformly mixed and fully oxidized. Inside ozone injection pipeline's exit end stretched into the import flue, ozone injection pipeline's exit end was provided with ozone injection apparatus, ozone injection apparatus's injection direction and flue gas flow direction are opposite, and ozone generating device 6 is the independent connection ozone layer respectively.

The absorbent feeding unit comprises an absorbent bin 1, a stirring device 4 and a buffer tank 5 which are connected in sequence along the feeding direction. The absorbent feeding unit further comprises a process water storage tank 3 and a conveying device 2, the process water storage tank 3 is independently connected into a stirring device 4 and a buffer tank 5 respectively, and the absorbent bin 1 is in butt joint with the stirring device 4 through the conveying device 2. The buffer tank 5 is respectively and independently connected with an absorption slurry nozzle 12 and an absorption slurry spraying layer 17.

The separation and dust removal unit is sequentially connected with a separation device 19 and a dust removal device 21 along the smoke discharge direction. The bottom discharge port of the separating device 19 is connected to the absorption slurry nozzle 12 through a return pipe, and the desulfurized fly ash separated by the separating device 19 is sprayed into the fluidized bed reaction device 8 through the return pipe and the absorption slurry nozzle 12. Further, a steam activation device 20 is arranged on the material return pipeline, and the steam activation device 20 is externally connected with a steam pipeline. The bottom discharge port of the dust removing device 21 is connected to a feed back pipeline, and the desulfurized fly ash collected at the bottom of the dust removing device 21 is mixed with the desulfurized fly ash collected at the bottom of the separating device 19 and then flows into the steam activating device 20 through the feed back pipeline. The outlet end of the dust removing device 21 is connected with a chimney 22.

In another embodiment, the invention provides a desulfurization and denitrification method by using ozone oxidation in cooperation with a semi-dry method, wherein the desulfurization and denitrification system device is used for desulfurization and denitrification of flue gas; the desulfurization and denitrification method specifically comprises the following steps:

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 2-10 kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of (0.8-1) to (1), and the contact time of the flue gas and the ozone in the mixing device 7 is 0.5-1.5 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is (2-3): 1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner barrel 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 1-100 mm and process water in a stirring device 4 according to the molar ratio of (5-20) to 1, standing for 5-30 min to obtain calcium hydroxide thick slurry with the solid content of 40-50%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 20-30% calcium hydroxide slurry, respectively spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur and nitrate in flue gas is (1-2) to 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow rate of ozone introduced into the first ozone injection layer 14 is 2-10 kg/h, and the molar ratio of the ozone injected into the first ozone injection layer 14 to NO in the flue gas is (0.8-1): 1; the mass flow rate of ozone introduced into the second ozone spraying layer 16 by the ozone generating device 6 is 1.5-8 kg/h, and the molar ratio of ozone sprayed by the second ozone spraying layer 16 to NO in the flue gas is (0.5-0.8): 1; the oxidant storage tanks 18 are respectively filled with first oxidantThe agent spraying layer 13 and the second oxidant spraying layer 15 spray a sodium chlorite solution with the pH value of 3-6 into the suspended fluidized bed layer, and the sodium chlorite solution and NO in the flue gas_xThe molar ratio of (1-2) to (1); NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 160-180 ℃, the residence time of the flue gas in the fluidized bed reaction device 8 is 3-8 s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 15-20 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19, 80-90% of desulfurization ash in the flue gas is separated and collected, the flue gas without the desulfurization ash enters a dust removal device 21 to recover residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) 1.5-3 kg/cm of steam at 50-60 deg.C²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

Example 1

The embodiment provides a flue gas desulfurization and denitrification method, which specifically comprises the following steps:

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 2kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of (1) to (2) is 0.8, and the contact time of the flue gas and the ozone in the mixing device 7 is 1.5 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 2:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner cylinder 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 1mm and process water in a stirring device 4 according to a molar ratio of 5:1, standing for 5min to obtain calcium hydroxide thick slurry with the solid content of 40%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 20% calcium hydroxide slurry, spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17 respectively, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur nitrate in flue gas is 1: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow of ozone introduced into the first ozone spraying layer 14 is 2kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 0.8: 1; the mass flow of ozone introduced into the second ozone spraying layer 16 by the ozone generating device 6 is 1.6kg/h, and the molar ratio of the ozone sprayed by the second ozone spraying layer 16 to NO in the flue gas is 0.5: 1; the oxidant storage tank 18 sprays sodium chlorite solution with pH of 3, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through the first oxidant spraying layer 13 and the second oxidant spraying layer 15 respectively_xIn a molar ratio of 1: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 160 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 3s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 15 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19, 80% of desulfurization ash in the flue gas is separated and collected, the flue gas without the desulfurization ash enters a dust removal device 21 to recover residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 50 deg.C at 1.5kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

The flue gas discharged from the chimney is sampled and detected, and the desulfurization rate is calculated to be 93.5 percent, and the denitration rate is calculated to be 92.6 percent.

Example 2

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 4kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of (1) to (2) is 0.84, the contact time of the flue gas and the ozone in the mixing device 7 is 1.3 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 2.2:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner barrel 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 20mm and process water in a stirring device 4 according to a molar ratio of 8:1, standing for 10min to obtain calcium hydroxide thick slurry with the solid content of 42%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 22% calcium hydroxide slurry, spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17 respectively, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur and nitrate in flue gas is 1.2: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generator 6 is respectively arranged in the suspended fluidized bed layer through the first ozone spraying layer 14 and the second ozone spraying layer 16Introducing ozone; the mass flow of ozone introduced into the first ozone spraying layer 14 is 4kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 0.84: 1; the mass flow of ozone introduced into the second ozone injection layer 16 by the ozone generating device 6 is 3kg/h, and the molar ratio of the ozone injected by the second ozone injection layer 16 to NO in the flue gas is 0.56: 1; the oxidant storage tank 18 sprays sodium chlorite solution with pH of 3.5, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through the first oxidant spraying layer 13 and the second oxidant spraying layer 15 respectively_xIn a molar ratio of 1.2: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 164 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 4s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 16 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19 to separate and collect 82% of desulfurization ash in the flue gas, the flue gas without the desulfurization ash enters a dust removal device 21 to recover the residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 52 ℃ at 1.8kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

The flue gas discharged from the chimney is sampled and detected, and the calculated desulfurization rate is 94.8 percent and the calculated denitration rate is 93.2 percent.

Example 3

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 5kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone, then is mixed and oxidized, and is in the inlet flueOzone and NO in flue gas_xThe molar ratio of the flue gas to the ozone is 0.88:1, and the contact time of the flue gas and the ozone in the mixing device 7 is 1.1 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 2.4:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner barrel 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 40mm and process water in a stirring device 4 according to a molar ratio of 11:1, standing for 15min to obtain calcium hydroxide thick slurry with the solid content of 44%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 24% calcium hydroxide slurry, respectively spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur nitrate in flue gas is 1.4: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow of the ozone introduced into the first ozone spraying layer 14 is 5kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 0.88: 1; the mass flow rate of ozone introduced into the second ozone spraying layer 16 by the ozone generating device 6 is 3.5kg/h, and the molar ratio of the ozone sprayed by the second ozone spraying layer 16 to NO in the flue gas is 0.62: 1; the oxidant storage tank 18 sprays sodium chlorite solution with pH of 4, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through the first oxidant spraying layer 13 and the second oxidant spraying layer 15 respectively_xIn a molar ratio of 1.4: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 168 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 5s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 17 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19, 84% of desulfurization ash in the flue gas is separated and collected, the flue gas without the desulfurization ash enters a dust removal device 21 to recover residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 54 deg.C at 2.1kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

The flue gas discharged from the chimney is sampled and detected, and the calculated desulfurization rate is 95.3 percent and the calculated denitration rate is 94.6 percent.

Example 4

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 6kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of the flue gas to the ozone is 0.92:1, and the contact time of the flue gas and the ozone in the mixing device 7 is 0.9 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 2.6:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner barrel 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 60mm and process water in a stirring device 4 according to a molar ratio of 14:1, standing for 20min to obtain calcium hydroxide thick slurry with the solid content of 46%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 26% calcium hydroxide slurry, spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17 respectively, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur nitrate in flue gas is 1.6: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow of ozone introduced into the first ozone spraying layer 14 is 6kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 0.92: 1; the mass flow of ozone introduced into the second ozone spraying layer 16 by the ozone generating device 6 is 4.2kg/h, and the molar ratio of the ozone sprayed by the second ozone spraying layer 16 to NO in the flue gas is 0.68: 1; the oxidant storage tank 18 sprays sodium chlorite solution with pH of 4.5, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through the first oxidant spraying layer 13 and the second oxidant spraying layer 15 respectively_xIn a molar ratio of 1.6: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 172 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 6s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 18 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19, 86% of desulfurization ash in the flue gas is separated and collected, the flue gas without the desulfurization ash enters a dust removal device 21 to recover residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 56 deg.C at 2.4kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

Sampling and detecting the flue gas discharged from the chimney, and calculating that the desulfurization rate is 94.2 percent and the denitration rate is 92.8 percent.

Example 5

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 8kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of the flue gas to the ozone is 0.96:1, and the contact time of the flue gas and the ozone in the mixing device 7 is 0.7 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 2.8:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner cylinder 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 80mm and process water in a stirring device 4 according to a molar ratio of 17:1, standing for 25min to obtain calcium hydroxide thick slurry with the solid content of 48%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 28% calcium hydroxide slurry, respectively spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur nitrate in flue gas is 1.8: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow of ozone introduced into the first ozone spraying layer 14 is 8kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 0.96: 1; the mass flow of ozone introduced into the second ozone spraying layer 16 by the ozone generating device 6 is 6.4kg/h, and the molar ratio of the ozone sprayed by the second ozone spraying layer 16 to NO in the flue gas is 0.74: 1; oxidant storage tank 18 respectively spraying a sodium chlorite solution with pH of 5, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through a first oxidant spraying layer 13 and a second oxidant spraying layer 15_xIn a molar ratio of 1.8: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 176 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 7s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 19 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19, 88 percent of desulfurization ash in the flue gas is separated and collected, the flue gas without the desulfurization ash enters a dust removal device 21 to recover the residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 58 deg.C at 2.7kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

The flue gas discharged from the chimney is sampled and detected, and the calculated desulfurization rate is 93.8 percent and the calculated denitration rate is 85.6 percent.

Example 6

(1) the mass flow of the ozone sprayed into the inlet flue by the ozone generating device 6 is 10kg/h, the flue gas is introduced into the inlet flue to be contacted with the ozone and then is mixed and oxidized, and in the inlet flue, the ozone and NO in the flue gas_xThe molar ratio of (1: 1) and the contact time of the flue gas and the ozone in the mixing device 7 is 0.5 s;

(2) the oxidized flue gas is divided into a first flue gas and a second flue gas, the volume flow ratio of the first flue gas to the second flue gas is 3:1, the first flue gas and the second flue gas are respectively introduced into the annular cavity and the inner cylinder 9 by adopting tangential air inlet, the air inlet directions of the first flue gas and the second flue gas are opposite, and rotational flows with opposite flow directions are formed in the fluidized bed reaction device 8;

(3) mixing and stirring calcium oxide with the particle size of 100mm and process water in a stirring device 4 according to a molar ratio of 20:1, standing for 30min to obtain calcium hydroxide thick slurry with the solid content of 50%, diluting the calcium hydroxide thick slurry with the process water in a buffer tank 5 to obtain 30% calcium hydroxide slurry, spraying the absorption slurry into a fluidized bed reaction device 8 through an absorption slurry nozzle 12 and an absorption slurry spraying layer 17 respectively, wherein the molar ratio of Ca in the calcium hydroxide slurry sprayed into the fluidized bed reaction device 8 to sulfur nitrate in flue gas is 2: 1; the absorption slurry forms a suspension fluidized bed layer in the fluidized bed reaction device 8, and SO2 in the flue gas reacts with calcium hydroxide in the suspension fluidized bed layer to realize desulfurization when the flue gas passes through the suspension fluidized bed layer;

(4) the ozone generating device 6 respectively injects ozone into the suspended fluidized bed layer through the first ozone injection layer 14 and the second ozone injection layer 16; the mass flow of ozone introduced into the first ozone spraying layer 14 is 10kg/h, and the molar ratio of the ozone sprayed by the first ozone spraying layer 14 to NO in the flue gas is 1: 1; the mass flow of ozone introduced into the second ozone injection layer 16 by the ozone generating device 6 is 8kg/h, and the molar ratio of the ozone injected by the second ozone injection layer 16 to NO in the flue gas is 0.8: 1; the oxidant storage tank 18 sprays sodium chlorite solution with pH of 6, the sodium chlorite solution and NO in the flue gas into the suspended fluidized bed layer through the first oxidant spraying layer 13 and the second oxidant spraying layer 15 respectively_xIn a molar ratio of 2: 1; NO in the flue gas when the flue gas passes through the suspended fluidized bed layer_xThe sulfur is reacted with oxidant and ozone in the suspension fluidized bed layer to realize desulfurization;

(5) the reaction temperature in the fluidized bed reaction device 8 is 180 ℃, the retention time of the flue gas in the fluidized bed reaction device 8 is 8s, and the flow velocity of the flue gas in the fluidized bed reaction device 8 is 20 m/s;

(6) the first flue gas and the second flue gas pass through the suspended fluidized bed layer for desulfurization, and contact with ozone and an oxidant for oxidation and denitration; the flue gas after desulfurization and denitrification is discharged and then enters a separation device 19 to separate and collect 90% of desulfurization ash in the flue gas, the flue gas without the desulfurization ash enters a dust removal device 21 to recover residual desulfurization ash in the flue gas, and the flue gas after dust removal is exhausted through a chimney 22;

(7) steam at 60 deg.C in a volume of 3kg/cm²The pressure of the gas is introduced into the steam activation device 20, the desulfurized fly ash collected by the separation device 19 and the desulfurized fly ash recovered after the flue gas is dedusted are mixed and fall into the steam activation device 20 to be contacted with the steam, and the activated desulfurized fly ash returns to the fluidized bed reaction device 8 for recycling.

The flue gas discharged from the chimney is sampled and detected, and the calculated desulfurization rate is 93.3 percent and the calculated denitration rate is 91.5 percent.

The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims

1. The desulfurization and denitrification system device is characterized by comprising an ozone oxidation unit, an absorbent feeding unit, a fluidized bed reaction unit and a separation and dust removal unit;

2. The SOx/NOx control system of claim 1, wherein the fluidized bed reaction unit comprises a fluidized bed reaction device;

preferably, the fluidized bed reaction device comprises a shell, an inner cylinder with two open ends is coaxially arranged below the inside of the shell, and an annular cavity is reserved between the shell and the inner cylinder; a first air inlet point position is arranged on the inner wall of the shell, and a second air inlet point position is arranged on the inner wall of the inner barrel;

preferably, the outlet end of the air inlet flue of the fluidized bed reaction device is divided into two paths, the two paths are respectively connected with the first air inlet point position and the second air inlet point position, the flue gas is divided into first flue gas and second flue gas, the first flue gas and the second flue gas respectively enter the fluidized bed reaction device, the first flue gas enters the annular cavity through the first air inlet point position in the tangential direction, the second flue gas enters the inner cylinder through the second air inlet point position in the tangential direction, and the tangential air inlet directions of the first flue gas and the second flue gas are opposite;

preferably, a nozzle for absorbing slurry is arranged in the inner cylinder and close to the smoke inlet end;

preferably, at least one ozone spraying layer, at least one oxidant spraying layer and one absorption slurry spraying layer are arranged above the inner cylinder along the flow direction of the flue gas, and the oxidant spraying layers are respectively and independently connected with an oxidant storage tank externally;

preferably, the ozone spraying layer and the oxidant spraying layer are alternately distributed;

preferably, the oxidant spraying layer comprises an annular spraying main pipe and a spray head arranged on the annular spraying main pipe;

preferably, a first oxidant spraying layer, a first ozone spraying layer, a second oxidant spraying layer, a second ozone spraying layer and an absorption slurry spraying layer are arranged above the inner cylinder along the flow direction of the flue gas.

3. The desulfurization and denitrification system device according to claim 1 or 2, wherein the ozone oxidation unit comprises a mixing device and an ozone generating device, the mixing device is connected to the inlet flue, the ozone generating device is connected to the inlet flue through an ozone injection pipeline, flue gas enters the inlet flue and then contacts with ozone input by the ozone generating device, and then enters the mixing device to be uniformly mixed and fully oxidized;

preferably, the outlet end of the ozone injection pipeline extends into the inlet flue;

preferably, the outlet end of the ozone injection pipeline is provided with an ozone injection device;

preferably, the spraying direction of the ozone spraying device is opposite to the flow direction of the flue gas;

4. The desulfurization and denitrification system device according to any one of claims 1-3, wherein the absorbent feeding unit comprises an absorbent bin, a stirring device and a buffer tank which are connected in sequence along a feeding direction;

preferably, the absorbent feeding unit further comprises a process water storage tank and a conveying device, wherein the process water storage tank is respectively and independently connected to the stirring device and the buffer tank, and the absorbent bin is in butt joint with the stirring device through the conveying device;

5. The desulfurization and denitrification system apparatus according to any one of claims 1 to 4, wherein the separation and dust removal unit comprises a separation apparatus and a dust removal apparatus which are connected in sequence along a flue gas discharge direction;

preferably, a discharge port at the bottom of the separation device is connected to the absorption slurry nozzle through a return pipeline, and the desulfurized ash separated by the separation device is sprayed into the fluidized bed reaction device through the return pipeline and the absorption slurry nozzle;

preferably, a steam activation device is arranged on the feed back pipeline, and the steam activation device is externally connected with a steam pipeline;

preferably, a discharge port at the bottom of the dust removal device is connected to the return pipeline, and the desulfurized fly ash collected at the bottom of the dust removal device is mixed with the desulfurized fly ash collected at the bottom of the separation device and then flows into the steam activation device through the return pipeline;

6. A desulfurization and denitrification method by using an ozone oxidation synergistic semidry method is characterized in that desulfurization and denitrification are carried out on flue gas by adopting the desulfurization and denitrification system device of any one of claims 1-5; the desulfurization and denitrification method comprises the following steps:

7. The desulfurization and denitrification method according to claim 6, which specifically comprises:

8. The desulfurization and denitrification method as claimed in claim 7, wherein in step (I), the mass flow rate of ozone sprayed into the inlet flue by the ozone generator is 2-10 kg/h;

preferably, the ozone generating device sprays ozone and NO in the flue gas into the inlet flue_xThe molar ratio of (0.8-1) to (1);

preferably, the contact time of the flue gas and the ozone in the mixing device is 0.5-1.5 s;

preferably, the volume flow ratio of the first flue gas to the second flue gas is (2-3): 1.

9. The desulfurization and denitrification method according to claim 7 or 8, wherein in the step (II), the absorbent is calcium oxide;

preferably, the particle size of the calcium oxide is 1-100 mm;

preferably, the calcium hydroxide thick slurry with the solid content of 40-50% is obtained after the calcium oxide and the process water are mixed and stirred;

preferably, the molar ratio of the calcium oxide to the process water is (5-20): 1;

preferably, mixing and stirring quicklime and process water, and standing for 5-30 min;

preferably, the calcium hydroxide thick slurry is diluted with process water to obtain calcium hydroxide slurry with the solid content of 20-30%;

preferably, the molar ratio of Ca in the calcium hydroxide slurry to the sulfur and nitrate in the flue gas is (1-2): 1;

preferably, the mass flow of ozone introduced into each ozone injection layer by the ozone generating device is gradually reduced along the flow direction of the flue gas;

preferably, the mass flow of ozone introduced into each ozone injection layer by the ozone generating device is gradually reduced along the flow direction of the flue gas according to a reduction ratio of 20-30%;

preferably, the mass flow of the ozone introduced into the first ozone injection layer by the ozone generating device is 2-10 kg/h;

preferably, the molar ratio of the ozone sprayed by the first ozone spraying layer to NO in the flue gas is (0.8-1): 1;

preferably, the mass flow rate of ozone introduced into the second ozone injection layer by the ozone generating device is 1.5-8 kg/h;

preferably, the molar ratio of the ozone sprayed by the second ozone spraying layer to NO in the flue gas is (0.5-0.8): 1;

preferably, the oxidant is sodium chlorite solution;

preferably, the pH value of the oxidant is 3-6;

preferably, the oxidant and NO in the flue gas_xThe molar ratio of (1-2) to (1);

preferably, the reaction temperature in the fluidized bed reaction device is 160-180 ℃;

preferably, the residence time of the flue gas in the fluidized bed reaction device is 3-8 s;

preferably, the flow speed of the flue gas in the fluidized bed reaction device is 15-20 m/s.

10. The desulfurization and denitrification method according to any one of claims 7-9, wherein in step (III), 80-90% of the desulfurization ash in the flue gas is separated and collected by a separation device, and the rest of the desulfurization ash in the flue gas is recovered by a dust removal device;

preferably, the steam is 1.5-3 kg/cm²The pressure of the steam is introduced into a steam activation device;

preferably, the steam temperature is 50-60 ℃.