Cooperative treatment system and method for solid waste and sintering flue gas based on circulating fluidized bed

Abstract

The invention provides a solid waste and sintering flue gas cooperative treatment system and method based on a circulating fluidized bed, and belongs to the field of flue gas purification and solid waste resource utilization. According to the system, an air distribution plate is arranged at the bottommost part of a hearth, a secondary air flue is arranged on one side of the middle part of the hearth, a bed material supplementing inlet is formed in the position, higher than the secondary air flue, of the other side of the hearth, a horizontal flue is arranged on the uppermost part of the hearth, and an SNCR device is arranged on the horizontal flue and then communicated with a cyclone separator; the gas fuel inlet of the primary fan is directly connected with the air distribution plate; an air chamber and a deslagging system are arranged at the bottom of the air distribution plate; the secondary air flue is communicated with a secondary fan through an air preheater; the solid waste bed material rich in free calcium comprises pretreated steel slag, blast furnace slag and / or carbide slag; and free calcium in the solid waste bed material reacts with SO2 in the high-temperature flue gas in the hearth to generate CaSO4, so that the removal of SO2 is realized. According to the invention, cooperative treatment of solid waste and flue gas is realized, and treatment of waste with waste is realized.

Description

Technical Field

[0001] The present invention belongs to the field of industrial flue gas purification and solid waste resource utilization, and particularly relates to a collaborative treatment system and method for solid waste and sintering flue gas based on a circulating fluidized bed. Background Art

[0002] A large amount of solid waste such as blast furnace slag and steel slag, as well as gaseous waste such as sintering flue gas, is generated during the iron and steel smelting process. Among them, blast furnace slag contains a large amount of oxides such as CaO, SiO2, Al2O3, MgO, MnO, and Fe2O3, as well as a small amount of sulfides, etc. Steel slag is composed of various oxides and salts formed by the oxidation of impurities such as silicon, manganese, phosphorus, and sulfur in pig iron during the smelting process. The long-term stacking of solid waste occupies a large amount of land resources and there is a risk of heavy metal leaching; while sintering flue gas contains high concentrations of sulfur dioxide (SO2), nitrogen oxides (NO X )), dioxins, and particulate matter and other pollutants, which are one of the main causes of atmospheric acid rain, haze, and photochemical smog. The direct discharge of solid waste and gaseous waste will not only cause environmental pollution, but also lead to a waste of resources. Therefore, it is necessary to develop resource utilization methods for solid waste and gaseous waste to reduce pollution while realizing the recycling of resources.

[0003] To meet the emission standards, sintering flue gas needs to be desulfurized and denitrified before discharge.

[0004] Traditional flue gas desulfurization technologies mainly include three categories: wet desulfurization, dry desulfurization, and semi-dry desulfurization. Among them, although wet desulfurization can achieve a high desulfurization efficiency, its equipment investment is large, energy consumption is high, wastewater treatment is complex, and operation and maintenance costs are relatively high, and it is only applicable to large-scale coal-fired power plants; while dry and semi-dry desulfurization have certain advantages in energy conservation and operation and maintenance, but there are deficiencies in aspects such as gas-solid contact, mass transfer and heat transfer, and absorbent reuse, and their overall desulfurization efficiency and system stability are still difficult to meet the strict requirements of ultra-low emissions in the iron and steel industry.

[0005] Flue gas denitrification technologies are mainly selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR). The SCR technology reduces NO under the conditions of 280 - 400°C and with a catalyst XReduced to N2, the denitration efficiency can reach 80% - 90%. However, the catalyst is expensive, the equipment investment cost is high, and the catalyst is prone to poisoning and inactivation under the conditions of high dust and high sulfur in sintering flue gas, and needs to be replaced regularly; the SNCR technology does not require a catalyst and directly sprays the reducing agent into the high-temperature flue, with less initial investment cost. However, due to the high temperature required for the reaction, the design requirements for the injection system and furnace structure are extremely strict; if the design is unreasonable, it may lead to low denitration efficiency and the risk of ammonia escape.

[0006] In the prior art, the circulating fluidized bed technology can be used to realize the desulfurization and denitration treatment of sintering flue gas. For example, the Chinese invention patent with the authorized publication number CN104107626B proposes a sintering flue gas circulating fluidized bed semi-dry combined desulfurization and denitration device and method. The device mainly includes an ozone generator, a dilution fan, a mixing buffer tank, an ozone distributor, and a CFB reaction tower. The generated ozone is evenly mixed in the mixing buffer tank and then sprayed into the flue through the ozone distributor; the oxidized flue gas is sent into the circulating fluidized bed reaction tower, and NO X , SO2 and SO3 in the flue gas react with the calcium-based absorbent under the action of atomized water in the reaction tower to realize simultaneous desulfurization and denitrification of the flue gas. Although this solution avoids the problem of wastewater discharge, reduces the calcium-sulfur ratio through material circulation, maintains a high desulfurization efficiency, and takes into account denitration and mercury removal at the same time, however, in this method, the system complexity and energy consumption increase significantly, the preparation cost of ozone and the consumption cost of activated carbon are relatively high, and the activated carbon is prone to failure after use and needs to be replaced frequently, with a low resource recycling rate. It can be seen that for the flue gas and solid waste treatment based on the circulating fluidized bed, there are still problems such as high cost and high complexity, and at the same time, the resource utilization of solid waste and flue gas cannot be realized simultaneously. Summary of the Invention

[0007] In view of the above defects or deficiencies in the prior art, the present invention aims to provide a collaborative treatment system and method for solid waste and sintering flue gas based on a circulating fluidized bed, which can simultaneously realize the resource utilization of solid waste and the desulfurization and denitration treatment of sintering flue gas in the circulating fluidized bed, and solve the problems of low resource utilization rate, complex process flow, high operation cost, and environmental pollution in the process of sintering flue gas purification and solid waste treatment in the steel industry.

[0008] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

[0009] In the first aspect, the embodiments of the present invention provide a collaborative treatment system for solid waste and sintering flue gas based on a circulating fluidized bed. The system includes a circulating fluidized bed CFB furnace 7, a primary fan 1, a secondary fan 2, a gas fuel inlet 3, a distributor plate 4, a secondary air flue 5, a bed material supplement inlet 6, an SNCR device 8, a cyclone separator 9, a return valve 10, an air preheater 11, and a solid waste bed material rich in free calcium; wherein,

[0010] At the bottommost part of the furnace chamber 7, there is an air distribution plate 4 provided. On one side of the middle part, there is a secondary air flue 5. At a position on the other side higher than the secondary air flue 5, there is a bed material replenishment inlet 6. At the uppermost part, there is a horizontal flue, and an SNCR device 8 is provided on the horizontal flue and then communicates with a cyclone separator 9;

[0011] The primary air blower 1 and the gas fuel inlet 3 are directly connected to the air distribution plate 4; an air chamber and a slag discharge system are provided at the bottom of the air distribution plate 4;

[0012] The secondary air flue 5 communicates with the secondary air blower 2 through an air preheater 11;

[0013] The lower end outlet of the cyclone separator 9 is connected to a return valve 10, and the return valve 10 is then connected to the bottom of the furnace chamber 7, and a flue gas outlet is provided at the upper part.

[0014] As a preferred embodiment of the present invention, the SNCR device 8 is arranged in the high-temperature flue gas area at the inlet of the cyclone separator 9, so that the reducing agent can fully react with NO in the flue gas before entering the cyclone separator X and thus smoothly achieve the efficient removal of NO X .

[0015] As a preferred embodiment of the present invention, the SNCR device 8 is an atomizing spraying device, which can atomize the denitration reducing agent and spray it into the horizontal flue to convert NO in the flue gas X into harmless N2 and water vapor to achieve flue gas denitration.

[0016] As a preferred embodiment of the present invention, the denitration reducing agent is urea solution or ammonia water.

[0017] As a preferred embodiment of the present invention, the solid waste bed material rich in free calcium includes pretreated steel slag, blast furnace slag and / or carbide slag.

[0018] As a preferred embodiment of the present invention, the pretreatment of the steel slag, blast furnace slag and / or carbide slag includes: crushing and screening the steel slag, blast furnace slag and / or carbide slag rich in free calcium to obtain materials with a predetermined particle size and storing them in a silo.

[0019] As a preferred embodiment of the present invention, the fuel gas includes coke oven gas, blast furnace gas and / or converter gas generated in the steel production process.

[0020] As a preferred embodiment of the present invention, the primary air blower 1 and the secondary air blower 2 are used to introduce combustion-supporting gas; the combustion-supporting gas is an oxygen-containing mixed gas.

[0021] As a preferred embodiment of the present invention, the connection between the side wall of the furnace 7 and the secondary air flue 5 is the secondary air inlet, and the position of the secondary air inlet is slightly higher than the bed height of the bed material inside the furnace 7. <> <>

[0022] In a second aspect, an embodiment of the present invention further provides a method for co-processing solid waste and sintering flue gas based on a circulating fluidized bed, and the method is implemented based on the co-processing system provided above; the method includes: <> <>

[0023] Crush and screen the industrial solid waste rich in free calcium to a predetermined particle size, store it in a silo, and use it as the absorbent bed material of the CFB; at the same time, quantitatively add it into the furnace interior through the bed material supplement inlet during the operation of the CFB, and continuously supplement the pre-treated solid waste bed material into the furnace to maintain the bed activity and fluidization state; <> <>

[0024] The primary air fan and the gas fuel inlet directly introduce the combustion-supporting gas and the gas fuel into the air chamber of the air distribution plate. After uniform air distribution and mixing through the air distribution plate, the fuel gas and the combustion-supporting gas enter the furnace interior together to participate in combustion; <> <>

[0025] The temperature in the furnace is maintained within the range of 800 - 900 °C to enable the fuel to burn fully to generate high-temperature flue gas, and ensure that the high-temperature flue gas is fully mixed and contacted with the bed material in the furnace; supplement the oxygen-containing combustion-supporting gas through the secondary air fan to maintain the required oxygen content in the furnace; at this time, the solid waste bed material and SO2 in the flue gas undergo a chemical reaction under the intense gas-solid turbulence state of the CFB, and the free calcium in the bed material reacts with SO2 in the flue gas to form CaSO4, thereby realizing the removal of SO2; <> <>

[0026] When the high-temperature flue gas is discharged from the top of the furnace through the horizontal flue, atomized denitrification reducing agent is sprayed into the flue gas through the SNCR device to convert NO <> X in the flue gas into harmless N2 and water vapor to achieve flue gas denitrification; <> <>

[0027] The high-temperature flue gas and solid particle mixture after desulfurization and denitrification enter the cyclone separator, and gas-solid separation is achieved through the cyclone separator; the flue gas is discharged from the flue gas outlet, and the solid particles flow back to the bottom of the furnace through the return valve at the bottom of the cyclone separator and continue to participate in the cyclic reaction as bed material; <> <>

[0028] The flue gas discharged from the flue gas outlet enters the subsequent dust removal system in sequence to remove fine particulate matter, ensuring that the particulate matter concentration in the finally discharged flue gas is lower than 10 mg / Nm <> 3 to achieve ultra-low pollution emission of the flue gas; <> <>

[0029] The bed material in the furnace with sufficient reaction and reduced activity is discharged outside the furnace through the slag discharge system of the air distribution plate. <> <>

[0030] The technical solution provided by the embodiment of the present invention has the following beneficial effects:

[0031] The collaborative treatment system and method for solid waste and sintering flue gas based on a circulating fluidized bed provided by the embodiments of the present invention replace traditional desulfurizing agents with industrial solid wastes such as steel slag and blast furnace slag, significantly reducing the absorbent cost and solid waste treatment cost in sintering flue gas treatment, and effectively reducing the overall operation cost of the system; based on the efficient gas-solid mixing method of the circulating fluidized bed and through a finely controlled flue gas desulfurization and denitrification process, the SO2 removal rate can be further stably achieved above 95%, and NO X The removal rate reaches above 85%; the by-product calcium sulfate produced in the production process, as a high-value-added product, can be used as a cement retarder or building material raw material, realizing the recycling of by-products and maximizing economic value, and significantly improving the resource recycling efficiency.

[0032] Of course, it is not necessary for any product or method of implementing the present invention to achieve all the above-mentioned advantages simultaneously. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0034] Figure 1 It is a schematic structural diagram of the collaborative treatment system for solid waste and sintering flue gas based on a circulating fluidized bed described in the embodiments of the present invention.

[0035] Description of the reference numerals:

[0036] 1 - primary air blower, 2 - secondary air blower, 3 - gas fuel inlet, 4 - air distribution plate, 5 - secondary air flue, 6 - bed material replenishment inlet, 7 - furnace, 8 - SNCR device, 9 - cyclone separator, 10 - return valve, 11 - air preheater. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] After discovering the above problems, the inventors of the present application conducted a detailed study on the existing solid waste and flue gas treatment technologies based on circulating fluidized beds. The study found that in the flue gas treatment process based on circulating fluidized beds, high requirements are imposed on the desulfurization and denitrification catalysts, resulting in the dependence on the continuous addition of chemical agents in the solution, leading to high operating costs. Moreover, the problem of resource utilization of by-products has not been solved, and the steel slag still needs secondary treatment after desulfurization, further increasing the costs of desulfurizer procurement and waste treatment. At the same time, traditional processes often carry out flue gas purification and solid waste treatment separately, resulting in large equipment investment, high operating costs, and high energy consumption. The circulating fluidized bed (CFB) technology has the characteristics of high gas-solid reaction efficiency, strong system flexibility, good mass and heat transfer, and continuous recyclability of absorbents. In a circulating fluidized bed, gas and solid can be fully mixed and contacted, strengthening the mass transfer reaction between pollutants and absorbents, enabling efficient desulfurization and denitrification to be achieved simultaneously in a single reactor. The high temperature condition of the flue gas itself can effectively avoid the need for catalysts in denitrification. At the same time, industrial solid wastes such as steel slag are used as desulfurization absorbents for resource utilization, achieving multi-pollutant synergistic purification by treating waste with waste. Based on the circulating fluidized bed, it is expected to build an integrated system for the collaborative treatment of multiple pollutants in sintering flue gas, promoting the leapfrog development of the iron and steel industry towards a low-carbon cycle direction.

[0038] It should be noted that all the defects existing in the above solutions of the prior art are the results obtained by the inventors through practice and careful research. Therefore, the process of discovering the above problems and the solutions proposed by the embodiments of the present invention below for the above problems should be the contributions made by the inventors to the present invention during the process of the present invention.

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Usually, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0040] It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. In the description of the present invention, the terms "first", "second", "third", "fourth", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0041] Based on the above in-depth analysis, the embodiments of the present invention provide a collaborative treatment system and method for solid waste and sintering flue gas based on a circulating fluidized bed. This system innovatively uses calcium-rich industrial solid wastes such as steel slag and blast furnace slag as both the bed material and desulfurization absorbent of the CFB, which not only realizes the resource utilization of solid wastes, reduces the environmental impact of solid waste stacking, but also reduces the operating cost during the desulfurization process. At the same time, by optimizing the layout of the purification system, efficient collaborative removal of SO2 and NO X in the flue gas is achieved, the process flow is simplified, and the treatment efficiency is improved. In addition, the free calcium content in the bed material after the reaction is significantly reduced, and it can be used in cement production or other building material fields after treatment, further reflecting the comprehensive utilization value of resources. Based on this, the present invention is expected to construct a multi-pollutant collaborative treatment system for sintering flue gas of "treating waste with waste" and promote the leapfrog development of the iron and steel industry towards the low-carbon cycle direction.

[0042] As Figure 1 shown, the collaborative treatment system for solid waste and sintering flue gas based on a circulating fluidized bed includes a CFB furnace 7, a primary air blower 1, a secondary air blower 2, a gas fuel inlet 3, a wind distribution plate 4, a secondary air flue 5, a bed material supplement inlet 6, an SNCR device 8, a cyclone separator 9, a return valve 10, an air preheater 11, and a solid waste bed material rich in free calcium.

[0043] Among them, a wind distribution plate 4 is arranged at the bottom of the furnace 7, a secondary air flue 5 is arranged on one side in the middle, a bed material supplement inlet 6 is arranged at a position on the other side higher than the secondary air flue 5, a horizontal flue is arranged at the top, and an SNCR device is arranged on the horizontal flue and then communicated with a cyclone separator 9.

[0044] The primary air blower inlet 1 and the gas fuel inlet 3 are directly connected to the wind distribution plate 4 to ensure that the combustion-supporting gas and the gas fuel are evenly mixed and then enter the furnace 7 for combustion. A wind chamber is arranged at the bottom of the wind distribution plate 4 for evenly mixing the combustion-supporting gas introduced by the primary air blower and the gas fuel. A slag discharge system is arranged on the wind distribution plate 4 to ensure the smooth discharge of furnace slag.

[0045] The secondary air flue 5 is communicated with the secondary air blower 2 through the air preheater 11. The air preheater 11 is used to send the combustion-supporting gas preheated by the air preheater 11 and introduced from the secondary air blower 2 into the furnace 7 through the secondary air flue 5. The combustion-supporting gas is an oxygen-containing combustion-supporting gas.

[0046] The bed material supplement inlet 6 is used to supplement the bed material obtained after the pretreatment of solid waste during the operation of the boiler, so that the pretreated solid waste bed material can be timely supplemented into the furnace to participate in the desulfurization reaction, maintaining the activity of the bed layer and a stable circulating fluidized state.

[0047] The cyclone separator 9 is used for gas-solid separation. The lower end outlet is connected to a return valve 10, and the return valve 10 is further connected to the bottom of the furnace 7. The upper part is provided with a flue gas outlet. The high-temperature flue gas from the furnace 7 is desulfurized and denitrified at the SNCR device 8 at the horizontal flue, and the flue gas separated by the cyclone separator is discharged from the flue gas outlet and enters the next stage of dust removal and purification treatment; the unreacted solid bed material separated is returned to the furnace 7 through the return valve 10 for recycling.

[0048] In a specific application example, preferably, the connection between the side wall of the furnace 7 and the secondary air flue 5 is the secondary air inlet, and the position of the secondary air inlet is slightly higher than the bed height of the bed material inside the furnace 7. By introducing the secondary air of the oxygen-containing combustion-supporting gas from the side wall, the oxygen supply in the middle and upper parts of the furnace can be strengthened to ensure the oxygen content required for combustion and reaction.

[0049] The bed material in the CFB furnace 7 is industrial solid waste rich in free calcium such as steel slag, blast furnace slag, and carbide slag.

[0050] Furthermore, the fuel gas includes but is not limited to industrial by-product fuel gases such as coke oven gas, blast furnace gas, and converter gas generated during the steel production process; among them, the industrial by-product gas fuel is coke oven gas or converter gas.

[0051] Furthermore, the combustion-supporting gas is an oxygen-containing mixed gas; preferably, the oxygen-containing mixed gas is sintering flue gas.

[0052] Furthermore, the denitrification reducing agent is urea or ammonia water.

[0053] Based on the same idea, the embodiment of the present invention also provides a method for co-processing solid waste and sintering flue gas based on a circulating fluidized bed. The method includes the following steps:

[0054] Step S1, crushing and screening the industrial solid waste rich in free calcium to a suitable particle size for pretreatment and storing it in a silo as the absorbent bed material of the CFB; at the same time, during the operation of the CFB, the pretreated industrial solid waste bed material is quantitatively added into the furnace 7 through the bed material supplement inlet 6 to continuously supplement the furnace with the pretreated industrial solid waste bed material to maintain the bed activity and fluidization state.

[0055] Step S2, the primary air blower 1 and the gas fuel inlet 3 directly introduce the oxygen-containing combustion-supporting gas and the gas fuel into the air chamber of the air distribution plate 4. After being evenly distributed and mixed by the air distribution plate 4, the fuel gas and the combustion-supporting gas enter the furnace 7 together to participate in combustion.

[0056] In step S3, the temperature in the furnace 7 is maintained within the range of 800 - 900 °C, enabling the fuel to burn fully to generate high-temperature flue gas and ensuring that the high-temperature flue gas is fully mixed and contacted with the bed material in the furnace 7; oxygen-containing combustion-supporting gas is supplemented through the secondary air blower to maintain the required oxygen content in the furnace. At this time, a chemical reaction occurs between the solid waste bed material and SO2 in the flue gas under the intense gas-solid turbulence state of the CFB. The free calcium in the bed material reacts with SO2 in the flue gas to form CaSO4, thereby achieving the removal of SO2.

[0057] In step S4, when the high-temperature flue gas is discharged from the top of the furnace 7 through the horizontal flue, an atomized denitrification reducing agent (urea solution or ammonia water) is sprayed into the flue gas through the SNCR device 8 to convert NO X in the flue gas into harmless N2 and water vapor, achieving flue gas denitrification.

[0058] In step S5, the high-temperature flue gas and the solid particle mixture after desulfurization and denitrification enter the cyclone separator 9, and gas-solid separation is achieved through the cyclone separator 9; the flue gas is discharged from the flue gas outlet, and the solid particles (unreacted bed material and generated solid products) flow back to the bottom of the furnace 7 from the bottom of the cyclone separator 9 through the return valve 10 and continue to participate in the cyclic reaction as bed material.

[0059] In step S6, the flue gas separated from the cyclone separator 9 enters the subsequent dust removal system in sequence to remove fine particulate matter, ensuring that the particulate matter concentration in the finally discharged flue gas is lower than 10 mg / Nm 3 , achieving ultra-low pollution emission of the flue gas.

[0060] In step S7, the bed material with sufficient reaction and reduced activity in the furnace is discharged outside the furnace through the slag discharge system of the air distribution plate. The main component of the discharged reaction product is still CaSO4. This by-product can be used as a cement retarder or for preparing 3D printing building materials, etc. after simple treatments such as drying, grinding, and screening, realizing the high-value utilization of industrial by-products.

[0061] It should be noted that the above steps do not have a strict chronological relationship and only represent the normal treatment process in the CFB boiler.

[0062] From the above technical solutions, it can be seen that the collaborative treatment system and method for solid waste and sintering flue gas based on the circulating fluidized bed provided by the embodiments of the present invention use industrial solid waste to replace traditional desulfurizing agents. Innovatively, industrial solid wastes such as steel slag, blast furnace slag, and carbide slag are crushed and their particle sizes are regulated and then used as the absorption bed material of the circulating fluidized bed to remove SO2 in the flue gas, designing and constructing a two-way resource recycling system of "treating waste with waste", effectively solving the collaborative problem of steel slag stacking and flue gas pollution control; realizing the removal of SO2 and NO in a single circulating fluidized bed for the industrial solid waste generated in the iron and steel production process and the sintering flue gas X, Simultaneous and efficient removal of particulate matter. Compared with traditional flue gas treatment processes, this co-treatment method improves the gas-solid reaction efficiency, enhances the multi-pollutant removal capacity, significantly reduces the overall process complexity and operating costs, and achieves the efficient co-treatment of multi-pollutants. At the same time, through the fine design of the circulating fluidized bed air distribution device and the scientific layout of the SNCR ammonia injection system, SO2 and NO in the flue gas X can be efficiently co-removed in a single device, and high-efficiency removal of NO can be achieved without an external catalyst X , significantly reducing the energy consumption of denitrification and the risk of ammonia escape, and further reducing the operating costs and equipment investment.

[0063] The above description is only the preferred embodiments of the present invention and the explanation of the applied technical principles, and is not intended to limit the scope of the present invention claimed, but only represents the preferred embodiments of the present invention. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the scope of protection of the present invention.

Claims

1. A collaborative treatment system for solid waste and sintering flue gas based on a circulating fluidized bed, characterized in that, The system includes a circulating fluidized bed (CFB) furnace (7), a primary air blower (1), a secondary air blower (2), a gas fuel inlet (3), a wind distribution plate (4), a secondary air flue (5), a bed material replenishment inlet (6), a selective non-catalytic reduction (SNCR) device (8), a cyclone separator (9), a return valve (10), an air preheater (11), and solid waste bed material rich in free calcium; wherein, A wind distribution plate (4) is provided at the bottommost part of the furnace (7), a secondary air flue (5) is provided on one side of the middle part, a bed material replenishment inlet (6) is provided at a position on the other side higher than the secondary air flue (5), a horizontal flue is provided at the uppermost part, and an SNCR device (8) is provided on the horizontal flue, and then it is connected to the cyclone separator (9); The primary air blower (1) and the gas fuel inlet (3) are directly connected to the wind distribution plate (4); a wind chamber and a slag discharge system are provided at the bottom of the wind distribution plate (4); The secondary air flue (5) is connected to the secondary air blower (2) through the air preheater (11); The lower end outlet of the cyclone separator (9) is connected to a return valve (10), and the return valve (10) is then connected to the bottom of the furnace (7), and a flue gas outlet is provided at the upper part.

2. The collaborative processing system according to claim 1, wherein The SNCR device (8) is arranged in the high-temperature flue gas area at the inlet of the cyclone separator (9), enabling the reducing agent to fully react with NO in the flue gas before entering the cyclone separator, so as to smoothly achieve the efficient removal of NO. X reaction, thus smoothly achieving the X efficient removal of NO.

3. The collaborative processing system according to claim 2, wherein The SNCR device (8) is an atomizing spray device, which can atomize the denitrification reducing agent and spray it into the horizontal flue to convert NO in the flue gas X into harmless N2 and water vapor, realizing flue gas denitrification.

4. The collaborative processing system according to claim 3, wherein The denitrification reducing agent is urea solution or ammonia water.

5. The collaborative processing system according to claim 1, wherein The solid waste bed material rich in free calcium includes pretreated steel slag, blast furnace slag, and / or carbide slag.

6. The collaborative processing system according to claim 5, wherein The pretreatment of steel slag, blast furnace slag, and / or carbide slag includes: crushing and screening the steel slag, blast furnace slag, and / or carbide slag rich in free calcium to obtain materials with a predetermined particle size, and storing them in a silo.

7. The collaborative processing system according to claim 1, wherein The fuel gas includes coke oven gas, blast furnace gas, and / or converter gas generated during the iron and steel production process.

8. The collaborative processing system according to claim 1, wherein The primary air blower (1) and the secondary air blower (2) are used to introduce combustion-supporting gas; the combustion-supporting gas is an oxygen-containing mixed gas.

9. The collaborative processing system according to claim 1, wherein The connection between the side wall of the furnace (7) and the secondary air flue (5) is the secondary air inlet, and the position of the secondary air inlet is slightly higher than the bed height of the bed material inside the furnace (7).

10. A collaborative treatment method for solid waste and sintering flue gas based on a circulating fluidized bed, characterized in that, The method is implemented based on the co-processing system provided in any one of claims 1-9; the method includes: Crushing and screening the industrial solid waste rich in free calcium to a predetermined particle size for pretreatment, and storing it in a silo as the absorbent bed material of the CFB; at the same time, during the operation of the CFB, quantitatively add it into the furnace interior through the bed material replenishment inlet, and continuously replenish the pretreated solid waste bed material into the furnace to maintain the bed layer activity and fluidization state; The primary air blower and the gas fuel inlet directly introduce the combustion-supporting gas and the gas fuel into the wind chamber of the wind distribution plate. After uniform air distribution and mixing through the wind distribution plate, the fuel gas and the combustion-supporting gas enter the furnace interior together to participate in combustion; The temperature inside the furnace is maintained within the range of 800-900 °C to enable the fuel to burn fully to generate high-temperature flue gas, and ensure that the high-temperature flue gas is fully mixed and contacted with the bed material inside the furnace; supplement the oxygen-containing combustion-supporting gas through the secondary air blower to maintain the required oxygen content inside the furnace; at this time, a chemical reaction occurs between the solid waste bed material and SO2 in the flue gas under the intense gas-solid turbulence state of the CFB, and the free calcium in the bed material reacts with SO2 in the flue gas to generate CaSO4, thereby achieving the removal of SO2; When the high-temperature flue gas is discharged from the top of the furnace through the horizontal flue, the atomized denitration reducing agent is injected into the flue gas through the SNCR device to convert NO in the flue gas X into harmless N2 and water vapor, realizing flue gas denitration; The high-temperature flue gas and solid particle mixture after desulfurization and denitrification enters a cyclone separator, where gas-solid separation is achieved; the flue gas is discharged from the flue gas outlet, and the solid particles flow back to the bottom of the furnace through a return valve at the bottom of the cyclone separator and continue to participate in the circulating reaction as bed material; The flue gas discharged from the flue gas outlet successively enters the subsequent dust removal system to remove fine particulate matter, ensuring that the particulate matter concentration in the finally discharged flue gas is lower than 10 mg / Nm 3 , achieving ultra-low pollution emission of the flue gas; The bed material with sufficient reaction and reduced activity in the furnace is discharged out of the furnace through the slag discharge system of the air distribution plate.

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