Synergistic carbon removal system and method for sintering flue gas pollutants

Abstract

The invention provides a collaborative carbon removal system for sintering flue gas pollutants. The collaborative carbon removal system comprises a primary dust remover, a desulfurization device, a secondary dust remover, a flue gas heat exchanger, a carbon monoxide catalytic oxidation device, an ammonia spraying device, a mixing device, an SCR (Selective Catalytic Reduction) denitration reactor and a carbon dioxide trapping device, the primary dust remover, the desulfurization device and the dust remover are sequentially connected with a desulfurized flue gas inlet of the flue gas heat exchanger, and a desulfurized flue gas outlet of the flue gas heat exchanger is sequentially connected with the carbon monoxide catalytic oxidation device, the ammonia spraying device, the mixing device, the SCR denitration reactor and a denitrated flue gas inlet of the flue gas heat exchanger; and a denitrified flue gas outlet of the flue gas heat exchanger is sequentially connected with the carbon dioxide trapping device. While conventional pollutants in the sintering flue gas are removed, carbon monoxide in the flue gas is oxidized into carbon dioxide through the carbon monoxide catalytic oxidation device, the temperature of the flue gas is increased through heat released in the oxidation process, then the denitration efficiency is improved, and extra energy consumption for flue gas temperature rise and heat compensation is reduced.

Description

Technical Field

[0001] The present invention relates to a sintering flue gas treatment system and method, and in particular to a sintering flue gas pollutant coordinated carbon removal system and method, belonging to the technical field of sintering flue gas pollution reduction and carbon reduction. Background Art

[0002] Sintering is one of the main processes in the steel industry. The pollutants SO 2 , NOx and particulate matter are the main sources of flue gas pollutants in the steel industry. The sintering flue gas control standards in the steel industry are getting higher and higher, especially when ultra-low emission requirements are implemented (SO 2 ≤35mg / Nm 3 , NOx≤50mg / Nm 3 , particulate matter ≤10mg / Nm 3 ), pollutant control technology needs to be continuously improved. At the same time, the sintering process in the steel industry is also one of the main sources of CO emissions, with a concentration of 5000-10000 mg / m 3 , which accounts for about 70% of the steel mill's CO emissions.

[0003] In the ultra-low emission technology of sintering flue gas pollutants, denitrification generally adopts an SCR denitrification reactor with a built-in medium-temperature denitrification catalyst. The reaction temperature is generally required to be around 280°C. After the sintering flue gas has passed through the flue gas heat exchanger after dust removal and desulfurization, the flue gas temperature is generally around 250°C. In order to improve the denitrification efficiency, it is necessary to supplement the flue gas after heat exchange to increase the flue gas temperature by about 30°C, which will consume a lot of heat energy.

[0004] Therefore, a system and method for synergistically treating pollutants and carbon in sintering flue gas is developed to synergistically remove CO and CO while making the sintering flue gas pollutant emissions reach ultra-low emission standards. 2 , and improving the denitrification efficiency while reducing the system energy consumption is very necessary for the environmental protection development in this field. Summary of the invention

[0005] Based on the above background, the purpose of the present invention is to provide a system and method for coordinated carbon removal of sintering flue gas pollutants to solve the problems described in the background technology.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A sintering flue gas pollutant coordinated carbon removal system comprises a primary dust collector, a desulfurization device, a secondary dust collector, a flue gas heat exchanger, a carbon monoxide catalytic oxidation device, an ammonia injection device, a mixing device, an SCR denitration reactor and a carbon dioxide capture device; the primary dust collector and the secondary dust collector are both used for dust removal of flue gas, the desulfurization device is used for desulfurization of flue gas, the flue gas heat exchanger is provided with a desulfurization flue gas inlet, a desulfurization flue gas outlet, a denitration flue gas inlet and a denitration flue gas outlet, the flue gas heat exchanger is used for heat exchange between desulfurization flue gas and denitration flue gas, the ammonia injection device is used for injecting a reducing agent ammonia into the flue gas after catalytic oxidation of carbon monoxide, and the The mixing device is used to mix nitrogen oxides in the flue gas with the reducing agent ammonia, the SCR denitrification reactor is used to denitrify the flue gas, and the carbon dioxide capture device is used to capture and remove carbon dioxide in the flue gas; the primary dust collector, the desulfurization device, the dust collector and the desulfurization flue gas inlet of the flue gas heat exchanger are connected in sequence, the desulfurization flue gas outlet of the flue gas heat exchanger is connected in sequence with the carbon monoxide catalytic oxidation device, the ammonia injection device, the mixing device, the SCR denitrification reactor and the denitrification flue gas inlet of the flue gas heat exchanger, and the denitrification flue gas outlet of the flue gas heat exchanger is connected in sequence.

[0008] Preferably, the sintering flue gas pollutant coordinated carbon removal system also includes a flue gas heat supplement device, a first regulating valve and a second regulating valve. The flue gas heat supplement device is arranged between the desulfurization flue gas outlet of the flue gas heat exchanger and the ammonia injection device. The flue gas heat supplement device is configured as a parallel bypass of the carbon monoxide catalytic oxidation device. The first regulating valve is arranged between the desulfurization flue gas outlet of the flue gas heat exchanger and the carbon monoxide catalytic oxidation device. The second regulating valve is arranged between the desulfurization flue gas outlet of the flue gas heat exchanger and the flue gas heat supplement device.

[0009] Preferably, the flue gas heat supplement device is used to supplement heat for part of the flue gas discharged from the desulfurization flue gas outlet of the flue gas heat exchanger, so that the temperature of this part of the flue gas after mixing with another part of the flue gas heated by the carbon monoxide catalytic oxidation device reaches above 280°C, the first regulating valve is used to adjust the amount of flue gas entering the carbon monoxide catalytic oxidation device, and the second regulating valve is used to adjust the amount of flue gas entering the flue gas heat supplement device.

[0010] Preferably, the flue gas heating device is a gas hot air furnace.

[0011] Preferably, the carbon monoxide catalytic oxidation device is loaded with a precious metal carbon monoxide catalyst, the ammonia injection device is a zoned adjustable ammonia injection device, the volume content of ammonia in its injection medium is less than 5%, the mixing device is a large-scale blade mixer, the SCR denitrification reactor is loaded with a medium-temperature denitrification catalyst, and the carbon dioxide capture device is a chemical absorption carbon dioxide capture device.

[0012] A method for sintering flue gas pollutant coordinated carbon removal using the sintering flue gas pollutant coordinated carbon removal system as described above, the method comprising the following steps:

[0013] The sintering flue gas is passed through a primary dust collector for preliminary dust removal;

[0014] The flue gas after preliminary dust removal is desulfurized by passing it through a desulfurization device;

[0015] The desulfurized flue gas is passed through a secondary dust collector for dust removal again;

[0016] The desulfurized flue gas after dust removal is passed through the flue gas heat exchanger to heat the desulfurized flue gas to increase its temperature to 250-252°C;

[0017] The heated flue gas is passed through a carbon monoxide catalytic oxidation device to oxidize the carbon monoxide in the flue gas into carbon dioxide and release heat, thereby further increasing the flue gas temperature by 28 to 55°C;

[0018] The flue gas after further heating is sprayed with reducing agent ammonia through an ammonia spraying device, and the nitrogen oxides in the flue gas and the reducing agent ammonia are uniformly mixed through a mixing device;

[0019] The uniformly mixed flue gas is passed through an SCR denitration reactor to remove nitrogen oxides in the flue gas, thereby obtaining denitration flue gas whose pollutant particulate matter content, sulfur dioxide content and nitrogen oxide content meet the emission standards;

[0020] The denitrified flue gas is passed through a flue gas heat exchanger for heat exchange and cooling, providing heat for the desulfurized flue gas in the flue gas heat exchanger;

[0021] The cooled flue gas is passed through a carbon dioxide capture device to capture and remove carbon dioxide from the flue gas.

[0022] Preferably, the method further comprises the following steps:

[0023] A parallel bypass having a second regulating valve and a flue gas heat supplement device is provided for the carbon monoxide catalytic oxidation device, and a first regulating valve is provided between the desulfurized flue gas outlet of the flue gas heat exchanger and the carbon monoxide catalytic oxidation device;

[0024] Monitor the flue gas temperature before entering the SCR denitrification reactor;

[0025] When the flue gas temperature before entering the SCR denitration reactor is monitored to be above 280°C, the second regulating valve and the flue gas heating device are closed;

[0026] When it is monitored that the flue gas temperature before entering the SCR denitrification reactor has not reached 280°C, the opening of the first regulating valve and the opening of the second regulating valve are adjusted to respectively adjust the amount of flue gas entering the carbon monoxide catalytic oxidation device and the amount of flue gas entering the flue gas heating device, and the flue gas in the parallel bypass is heated by the flue gas heating device, and the heated flue gas is mixed with the flue gas passing through the carbon monoxide catalytic oxidation device and the reducing agent ammonia injected by the ammonia injection device through a mixing device, so that the flue gas temperature before entering the SCR denitrification reactor reaches above 280°C.

[0027] Preferably, the adjusting the opening of the first regulating valve and the opening of the second regulating valve specifically comprises the following steps:

[0028] The target temperature of the opening control is set to 280°C, which is the target flue gas temperature before entering the SCR denitration reactor;

[0029] Measuring the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device, the carbon monoxide concentration of the flue gas at the outlet of the carbon monoxide catalytic oxidation device and the outlet flue gas temperature;

[0030] Based on the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device, the heat released by the carbon monoxide catalytic oxidation Q and the expected flue gas temperature rise ΔT are calculated by the following calculation formula: p ,

[0031] Q=ΔH·F·(CO in -CO out );

[0032]

[0033] In the formula, ΔH represents the reaction heat of carbon monoxide oxidation, F represents the flue gas flow rate, CO in Indicates the carbon monoxide concentration in the flue gas at the inlet of the carbon monoxide catalytic oxidation device, CO out Indicates the carbon monoxide concentration in the flue gas at the outlet of the carbon monoxide catalytic oxidation device, C p represents the molar heat capacity of flue gas;

[0034] The feedforward control term FF of the valve opening is calculated by the following formula:

[0035] FF=K f ΔT p ;

[0036] In the formula, K f represents the feedforward gain coefficient;

[0037] Calculate the difference between the target temperature and the actual flue gas temperature before entering the SCR denitration reactor as the temperature error e(t);

[0038] Use the PID controller to calculate the opening fine-tuning control term u of the first regulating valve by the following calculation formula: 1 (t) and the second regulating valve opening fine-tuning control term u 2 (t),

[0039]

[0040] In the formula, K p1 , K p2 is the proportionality coefficient, K i1 , K i2 is the integration coefficient, K d1 , K d2 is the differential coefficient;

[0041] Combine the feedforward control term with the opening fine-tuning control term to calculate the final opening Z of the first regulating valve by the following calculation formula: 1 and the final opening Z of the second regulating valve 2 ,

[0042] Z 1 =FF+u 1 (t);

[0043] Z 2 =100%-FF+u 1 (t);

[0044] In the formula, Z 1 and Z 2 The minimum value of Z is 0. 1 and Z 2 The maximum value of is 100%.

[0045] Compared with the prior art, the present invention has the following advantages:

[0046] A sintering flue gas pollutant coordinated carbon removal system of the present invention, while removing conventional pollutants in the sintering flue gas, oxidizes the carbon monoxide in the flue gas into carbon dioxide through a carbon monoxide catalytic oxidation device, and uses the heat released in the oxidation process to increase the flue gas temperature, thereby improving the denitrification efficiency and saving additional energy consumption for flue gas heating; the carbon dioxide generated by oxidation and the original carbon dioxide in the sintering flue gas are removed together in a subsequent carbon dioxide capture device, effectively reducing greenhouse gas emissions and achieving the purpose of energy saving and carbon reduction; the present invention realizes the coordinated carbon removal of pollutants in the whole process of sintering flue gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0048] Figure 1 is a schematic diagram of a sintering flue gas pollutant coordinated carbon removal system of the present invention;

[0049] Figure 2 It is a flow chart of a method for collaborative carbon removal of sintering flue gas pollutants according to the present invention;

[0050] Figure 3 This is a flue gas heat supplementation flow chart of a method for collaborative carbon removal of sintering flue gas pollutants according to the present invention;

[0051] In the figure: 1. primary dust collector; 2. desulfurization device; 3. secondary dust collector; 4. flue gas heat exchanger; 5. carbon monoxide catalytic oxidation device; 6. flue gas heat supplement device; 7. ammonia injection device; 8. mixing device; 9. SCR denitrification reactor; 10. carbon dioxide capture device; 11. chimney; Z1, first regulating valve; Z2, second regulating valve. DETAILED DESCRIPTION

[0052] The technical solution of the present invention is further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any form of modification and / or change made to the present invention will fall within the protection scope of the present invention.

[0053] In the present invention, unless otherwise specified, all parts and percentages are weight units, and the equipment and raw materials used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are universal standard parts or components known to those skilled in the art, and their structures and principles are known to those skilled in the art through technical manuals or conventional experimental methods.

[0054] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention. However, one or more embodiments may also be implemented by those skilled in the art without these specific details.

[0055] like Figure 1A sintering flue gas pollutant coordinated carbon removal system is shown, comprising a primary dust collector 1, a desulfurization device 2, a secondary dust collector 3, a flue gas heat exchanger 4, a carbon monoxide catalytic oxidation device 5, an ammonia injection device 7, a mixing device 8, an SCR denitrification reactor 9 and a carbon dioxide capture device 10.

[0056] The primary dust collector 1 and the secondary dust collector 3 are both used for removing dust from the flue gas, the desulfurization device 2 is used for desulfurizing the flue gas, the flue gas heat exchanger 4 is provided with a desulfurization flue gas inlet, a desulfurization flue gas outlet, a denitrification flue gas inlet and a denitrification flue gas outlet, the flue gas heat exchanger 4 is used for heat exchange between the desulfurization flue gas and the denitrification flue gas, the ammonia injection device 7 is used for injecting reducing agent ammonia into the flue gas after catalytic oxidation of carbon monoxide, the mixing device 8 is used for mixing nitrogen oxides in the flue gas with reducing agent ammonia, the SCR denitrification reactor 9 is used for denitrifying the flue gas, and the carbon dioxide capture device 10 is used for capturing and removing carbon dioxide in the flue gas.

[0057] The primary dust collector 1, the desulfurization device 2, the dust collector and the desulfurization flue gas inlet of the flue gas heat exchanger 4 are connected in sequence, the desulfurization flue gas outlet of the flue gas heat exchanger 4 is connected in sequence with the carbon monoxide catalytic oxidation device 5, the ammonia injection device 7, the mixing device 8, the SCR denitrification reactor 9 and the denitrification flue gas inlet of the flue gas heat exchanger 4, and the denitrification flue gas outlet of the flue gas heat exchanger 4 is connected in sequence with the carbon dioxide capture device 10.

[0058] In the prior art, the SCR denitration reactor 9 is equipped with a medium-temperature denitration catalyst, and the reaction temperature is generally required to be about 280°C. After the sintering flue gas passes through the flue gas heat exchanger 4 after dust removal and desulfurization, the flue gas temperature is generally about 250°C. In order to improve the denitration efficiency, it is necessary to supplement the heat of the flue gas after heat exchange to increase the flue gas temperature by about 30°C, which will consume a lot of heat energy. Since the oxidation of carbon monoxide is an exothermic reaction, the complete oxidation of carbon monoxide can increase the flue gas temperature by 28 to 55°C. The carbon monoxide catalytic oxidation device 5 is arranged upstream of the SCR denitration reactor 9, which can effectively increase the flue gas temperature, reduce the energy consumption of supplementary heat, save energy and reduce carbon emissions, and improve the denitration efficiency.

[0059] If the concentration of carbon monoxide in the flue gas is high enough, there is no need to add additional heat to the flue gas. However, considering the low concentration of carbon monoxide in the flue gas and the low flue gas temperature at the start of the sintering process that cannot reach the catalytic oxidation temperature of carbon monoxide, which easily leads to carbon monoxide catalyst poisoning, the sintering flue gas pollutant coordinated carbon removal system is also equipped with a flue gas heat supplement bypass.

[0060] Specifically, the sintering flue gas pollutant coordinated carbon removal system also includes a flue gas heat supplement device 6, a first regulating valve Z1 and a second regulating valve Z2. The flue gas heat supplement device 6 is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger 4 and the ammonia injection device 7. The flue gas heat supplement device 6 is configured as a parallel bypass of the carbon monoxide catalytic oxidation device 5. The first regulating valve Z1 is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger 4 and the carbon monoxide catalytic oxidation device 5. The second regulating valve Z2 is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger 4 and the flue gas heat supplement device 6. At this time, the mixing device 8 is also used to mix the flue gas heated by the flue gas heat supplement device 6 with the flue gas catalytically oxidized by the carbon monoxide catalytic oxidation device 5. In addition, the sintering flue gas pollutant coordinated carbon removal system also includes a chimney 11, which is used to discharge the clean flue gas after the capture and removal of carbon dioxide.

[0061] Among them, the flue gas heat supplement device 6 is used to supplement heat for part of the flue gas discharged from the desulfurization flue gas outlet of the flue gas heat exchanger 4, so that the temperature of this part of the flue gas after mixing with another part of the flue gas heated by the carbon monoxide catalytic oxidation device 5 reaches above 280°C, the first regulating valve Z1 is used to adjust the amount of flue gas entering the carbon monoxide catalytic oxidation device 5, and the second regulating valve Z2 is used to adjust the amount of flue gas entering the flue gas heat supplement device 6.

[0062] Specifically, the flue gas heating device 6 is a gas hot air furnace. Of course, an electric heater can also be used.

[0063] Specifically, the carbon monoxide catalytic oxidation device 5 is loaded with a precious metal carbon monoxide catalyst. Of course, a transition metal carbon monoxide catalyst can also be used. The ammonia injection device 7 is a zoned adjustable ammonia injection device 7, and the volume content of ammonia in its injection medium is less than 5%. The mixing device 8 is a large-scale blade mixer. Of course, a static mixing device 8 such as a tubular mixer can also be used. The SCR denitration reactor 9 is loaded with 2+1 or 3+1 layers of denitration catalyst, specifically a medium-temperature denitration catalyst. Of course, a low-temperature denitration catalyst can also be used. The carbon dioxide capture device 10 is a chemical absorption carbon dioxide capture device, such as a chemical absorption carbon dioxide capture device using an amine method, an alkali solution washing method, or a thermally activated potassium carbonate method. Of course, other types of carbon dioxide capture devices can also be used, for example, physical absorption carbon dioxide capture devices using low-temperature methanol method, polyethylene glycol dimethyl ether method, and propylene carbonate method, adsorption separation carbon dioxide capture devices using pressure swing adsorption method, temperature swing adsorption method, and vacuum swing adsorption method, and membrane separation carbon dioxide capture devices using polymer membrane method, inorganic membrane method, and mixed matrix membrane method.

[0064] The sintering flue gas pollutant and carbon removal system removes conventional pollutants from the sintering flue gas, and oxidizes the carbon monoxide in the flue gas into carbon dioxide through the carbon monoxide catalytic oxidation device 5, and uses the heat released during the oxidation process to increase the flue gas temperature, thereby improving the denitrification efficiency and saving the additional energy consumption for heating the flue gas. The carbon dioxide generated by oxidation and the original carbon dioxide in the sintering flue gas are removed together in the subsequent carbon dioxide capture device 10, effectively reducing greenhouse gas emissions and achieving the purpose of energy saving and carbon reduction.

[0065] like Figure 2 As shown, a method for synergistic carbon removal of sintering flue gas pollutants using the above-mentioned synergistic carbon removal system for sintering flue gas pollutants comprises the following steps:

[0066] The sintering flue gas is passed through a primary dust collector 1 for preliminary dust removal;

[0067] The flue gas after preliminary dust removal is desulfurized by passing it through a desulfurization device 2;

[0068] The desulfurized flue gas is passed through a secondary dust collector 3 for dust removal again;

[0069] The desulfurized flue gas after the dust removal is passed through the flue gas heat exchanger 4 to exchange heat, so that the temperature of the desulfurized flue gas is increased to 250-252°C;

[0070] The heated flue gas passes through the carbon monoxide catalytic oxidation device 5, so that the carbon monoxide in the flue gas is oxidized into carbon dioxide and releases heat, thereby further increasing the flue gas temperature by 28 to 55°C;

[0071] The flue gas after further heating is sprayed with reducing agent ammonia through the ammonia spraying device 7, and the nitrogen oxides in the flue gas and the reducing agent ammonia are uniformly mixed through the mixing device 8;

[0072] The uniformly mixed flue gas is passed through an SCR denitration reactor 9 to remove nitrogen oxides in the flue gas, thereby obtaining a denitration flue gas whose pollutant particulate matter content, sulfur dioxide content and nitrogen oxide content meet the emission standards;

[0073] The denitrified flue gas is passed through the flue gas heat exchanger 4 for heat exchange and cooling, thereby providing heat for the desulfurized flue gas in the flue gas heat exchanger 4;

[0074] The flue gas after cooling is passed through the carbon dioxide capture device 10 to capture and remove carbon dioxide in the flue gas.

[0075] like Figure 3 As shown, the method further comprises the following steps:

[0076] A parallel bypass having a second regulating valve Z2 and a flue gas heat supplement device 6 is provided for the carbon monoxide catalytic oxidation device 5, and a first regulating valve Z1 is provided between the desulfurized flue gas outlet of the flue gas heat exchanger 4 and the carbon monoxide catalytic oxidation device 5;

[0077] Monitor the flue gas temperature before entering the SCR denitration reactor 9;

[0078] When it is monitored that the flue gas temperature before entering the SCR denitration reactor 9 reaches above 280°C, the second regulating valve Z2 and the flue gas heating device 6 are closed;

[0079] When it is monitored that the flue gas temperature before entering the SCR denitration reactor 9 has not reached 280°C, the opening of the first regulating valve Z1 and the opening of the second regulating valve Z2 are adjusted, so as to adjust the flue gas amount entering the carbon monoxide catalytic oxidation device 5 and the flue gas amount entering the flue gas heating device 6 respectively, and the flue gas in the parallel bypass is heated by the flue gas heating device 6, and the heated flue gas is mixed with the flue gas passing through the carbon monoxide catalytic oxidation device 5 and the reducing agent ammonia injected by the ammonia injection device 7 through the mixing device 8, so that the flue gas temperature before entering the SCR denitration reactor 9 reaches above 280°C.

[0080] The step of adjusting the opening of the first regulating valve Z1 and the opening of the second regulating valve Z2 specifically includes the following steps:

[0081] The target temperature of the opening control is set to 280°C, which is the target flue gas temperature before entering the SCR denitration reactor 9;

[0082] Measuring the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device 5, the carbon monoxide concentration of the flue gas at the outlet of the carbon monoxide catalytic oxidation device 5, and the outlet flue gas temperature;

[0083] Based on the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device 5, the heat released by the carbon monoxide catalytic oxidation Q and the expected flue gas temperature rise ΔT are calculated by the following calculation formula: p ,

[0084] Q=ΔH·F·(CO in -CO out );

[0085]

[0086] In the formula, ΔH represents the reaction heat of carbon monoxide oxidation, F represents the flue gas flow rate, CO in represents the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device 5, CO out represents the carbon monoxide concentration of the flue gas at the outlet of the carbon monoxide catalytic oxidation device 5, C p represents the molar heat capacity of flue gas;

[0087] The feedforward control term FF of the valve opening is calculated by the following formula:

[0088] FF=K f ΔT p ;

[0089] In the formula, K f represents the feedforward gain coefficient;

[0090] Calculate the difference between the target temperature and the actual flue gas temperature before entering the SCR denitration reactor 9 as the temperature error e(t);

[0091] Use the PID controller to calculate the opening fine-tuning control term u of the first regulating valve Z1 by the following calculation formula: 1 (t) and the opening fine-tuning control term u of the second regulating valve Z2 2 (t),

[0092]

[0093] In the formula, K p1 , K p2 is the proportionality coefficient, K i1 , K i2 is the integration coefficient, K d1 , K d2 is the differential coefficient;

[0094] Combine the feedforward control term with the opening fine-tuning control term to calculate the final opening Z of the first regulating valve Z1 by the following calculation formula: 1 and the final opening Z of the second regulating valve Z2 2 ,

[0095] Z 1 =FF+u 1 (t);

[0096] Z 2 =100%-FF+u 1 (t);

[0097] In the formula, Z 1 and Z 2 The minimum value of Z is 0. 1 and Z 2 The maximum value of is 100%.

[0098] Application Example 1

[0099] A sintering flue gas pollutant coordinated carbon removal system and method, used in a steel enterprise 450m 2 Synergistic carbon removal of sintering machine flue gas pollutants.

[0100] Flue gas parameters: Flue gas volume 2010000Nm3 / h (standard state), flue gas temperature 150℃, SO 2 Concentration 1200mg / Nm 3 、NOx concentration 200mg / Nm 3 、Particle concentration 2.5g / Nm 3 、CO concentration is 7000mg / Nm 3 .

[0101] During normal operation, the sintering flue gas first enters the electric bag composite dust collector for primary dust removal, and the particle concentration is 30mg / Nm 3 Then, a semi-dry desulfurization system is used to remove SO from the flue gas. 2 After desulfurization, the secondary dust removal is carried out by the bag filter. At this time, the flue gas temperature in the sintering flue gas is about 90℃, SO 2 Concentration 30mg / Nm 3 , the particle concentration is about 8mg / Nm 3 .

[0102] The flue gas after desulfurization and dust removal enters the rotary flue gas heat exchanger 4. After heat exchange, the flue gas temperature rises to 252°C, and then passes through the first regulating valve Z1 and enters the carbon monoxide catalytic oxidation device 5. The carbon monoxide catalytic oxidation device 5 has two layers of precious metal catalysts built in it to catalytically oxidize CO into CO 2 Heat is released, and the CO concentration is 1400 at this time. The flue gas temperature is raised by 31°C to about 283°C, and then mixed with the reducing agent ammonia sprayed by the ammonia spray device 7. Ammonia is produced by pyrolysis of urea, and then mixed with air at room temperature and enters the ammonia spray device 7.

[0103] After the ammonia and flue gas are mixed, they flow through a large-scale swirl blade static mixer to evenly mix the ammonia and nitrogen oxides in the flue gas, ensuring that the ammonia nitrogen molar ratio concentration is less than 5%. The flue gas temperature drops to about 282°C and enters the SCR denitration reactor 9. The SCR denitration reactor has a built-in "2+1" layer of medium-temperature denitration catalyst. The NOx concentration in the flue gas after denitration is 40mg / Nm 3 .

[0104] The flue gas after pollutant removal enters the rotary flue gas heat exchanger 4 again for heat exchange. At this time, the flue gas temperature drops to 120℃. After passing through the pre-spray tower, the flue gas temperature drops to 50℃ before entering the chemical absorption carbon dioxide capture device. The absorbent is organic amine. 2 The removal efficiency is 80%, and the decarbonized flue gas enters the chimney 11 and is discharged into the atmosphere.

[0105] In this application example, when starting the furnace, the desulfurization and dust removal processes are consistent with the normal operating conditions. After passing through the rotary flue gas heat exchanger 4, it is necessary to close the first regulating valve Z1 to prevent the flue gas from entering the carbon monoxide catalytic oxidation device 5, and open the second regulating valve Z2 to allow the flue gas to pass completely through the bypass, and pass through the gas hot blast furnace for supplementary heat. The low-temperature flue gas is heated by burning blast furnace gas. The heated flue gas passes through the ammonia injection device 7 and the large-size blade cyclone static mixer to ensure that the flue gas temperature and the ammonia nitrogen molar ratio are evenly mixed, and then the minimum flue gas temperature at the inlet section of the first catalyst of the SCR denitration device reaches 280°C, and then the flue gas denitration and subsequent decarbonization processes are carried out. After normal operation, open the first regulating valve Z1, close the second regulating valve Z2, and then carry out the normal operation process.

[0106] Application Example 2

[0107] A sintering flue gas pollutant coordinated carbon removal system and method, used in a steel enterprise 240m 2 Synergistic carbon removal of sintering machine flue gas pollutants.

[0108] Smoke parameters: Smoke volume 1000000Nm 3 / h (standard state), flue gas temperature 135℃, SO 2 Concentration 1150mg / Nm 3 、NOx concentration 280mg / Nm 3 、Particle concentration 3g / Nm 3 、CO concentration is 6000mg / Nm 3 .

[0109] During normal operation, the sintering flue gas first enters the dry electrostatic precipitator for primary dust removal, and the particle concentration is 50mg / Nm 3 Then, a wet desulfurization system is used to remove SO from the flue gas. 2 After desulfurization, the flue gas is subjected to secondary dust removal in a wet dust collector. At this time, the flue gas temperature in the sintering flue gas is about 55°C, and SO 2 Concentration 28mg / Nm 3 , the particle concentration is about 10mg / Nm 3 .

[0110] The flue gas after desulfurization and dust removal enters the rotary flue gas heat exchanger 4. After heat exchange, the flue gas temperature rises to 250°C. Then, after the opening of the first regulating valve Z1 and the second regulating valve Z2 is adjusted, about 90% of the flue gas enters the carbon monoxide catalytic oxidation device 5. The carbon monoxide catalytic oxidation device 5 has two layers of precious metal catalysts built in to catalytically oxidize CO into CO 2And release heat, at this time the CO concentration is 1000, the flue gas temperature is about 278°C after rising by 28°C, so that about 10% of the flue gas enters the flue gas supplementary heating device 6, the flue gas supplementary heating device 6 is an electric heating furnace, and the bypass flue gas is heated to 308°C. After the two parts of the flue gas are mixed, they are mixed with the reducing agent ammonia sprayed by the ammonia spraying device 7. Ammonia is produced by pyrolysis of urea, and then mixed with air at room temperature and enters the ammonia spraying device 7.

[0111] After the ammonia and flue gas are mixed, they flow through a tubular static mixer to evenly mix the ammonia and nitrogen oxides in the flue gas, ensuring that the molar ratio of ammonia and nitrogen is less than 5%. The flue gas temperature drops to about 280°C and enters the SCR denitration reactor 9. The SCR denitration reactor has a built-in "3+1" layer of medium-temperature denitration catalyst. The NOx concentration in the flue gas after denitration is 38mg / Nm 3 .

[0112] The flue gas after pollutant removal enters the rotary flue gas heat exchanger 4 again for heat exchange. At this time, the flue gas temperature drops to 87°C. After passing through the pre-spray tower, the flue gas temperature drops to below 40°C, and then enters the physical adsorption carbon dioxide capture device. The adsorbent is activated carbon. 2 The removal efficiency is 90%, and the decarbonized flue gas enters the chimney 11 and is discharged into the atmosphere.

[0113] In this application example, when starting the furnace, the desulfurization and dust removal processes are consistent with the normal operating conditions. After passing through the rotary flue gas heat exchanger 4, it is necessary to close the first regulating valve Z1 to prevent the flue gas from entering the carbon monoxide catalytic oxidation device 5, and open the second regulating valve Z2 to allow the flue gas to pass completely through the bypass and pass through the electric heating furnace for supplementary heat. The low-temperature flue gas is heated to 281°C by electric heating. The heated flue gas passes through the ammonia injection device 7 and the tubular static mixer, and the temperature is reduced to 280°C, and then enters the SCR denitration reactor 9 for denitration and subsequent processes. Although the entire process of this application example requires electric heating, the supplementary heat energy consumption is greatly reduced compared to the system energy consumption of the prior art without the carbon monoxide catalytic oxidation device 5.

[0114] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A sintering flue gas pollutant coordinated carbon removal system, characterized in that: The sintering flue gas pollutant coordinated carbon removal system comprises a primary dust collector (1), a desulfurization device (2), a secondary dust collector (3), a flue gas heat exchanger (4), a carbon monoxide catalytic oxidation device (5), an ammonia injection device (7), a mixing device (8), an SCR denitration reactor (9) and a carbon dioxide capture device (10); the primary dust collector (1) and the secondary dust collector (3) are both used for dust removal of flue gas, the desulfurization device (2) is used for desulfurization of flue gas, the flue gas heat exchanger (4) is provided with a desulfurization flue gas inlet, a desulfurization flue gas outlet, a denitration flue gas inlet and a denitration flue gas outlet, the flue gas heat exchanger (4) is used for heat exchange between desulfurization flue gas and denitration flue gas, the ammonia injection device (7) is used for injecting a reducing agent ammonia into the flue gas after carbon monoxide catalytic oxidation, and the The mixing device (8) is used to mix nitrogen oxides in the flue gas with ammonia as a reducing agent, the SCR denitrification reactor (9) is used to denitrify the flue gas, and the carbon dioxide capture device (10) is used to capture and remove carbon dioxide in the flue gas; the primary dust collector (1), the desulfurization device (2), the dust collector and the desulfurization flue gas inlet of the flue gas heat exchanger (4) are connected in sequence, the desulfurization flue gas outlet of the flue gas heat exchanger (4) is connected in sequence with the carbon monoxide catalytic oxidation device (5), the ammonia injection device (7), the mixing device (8), the SCR denitrification reactor (9) and the denitrification flue gas inlet of the flue gas heat exchanger (4), and the denitrification flue gas outlet of the flue gas heat exchanger (4) is connected in sequence.

2. The sintering flue gas pollutant coordinated carbon removal system according to claim 1 is characterized by: The sintering flue gas pollutant coordinated carbon removal system also includes a flue gas heat supplement device (6), a first regulating valve (Z1) and a second regulating valve (Z2). The flue gas heat supplement device (6) is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger (4) and the ammonia injection device (7). The flue gas heat supplement device (6) is configured as a parallel bypass of the carbon monoxide catalytic oxidation device (5). The first regulating valve (Z1) is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger (4) and the carbon monoxide catalytic oxidation device (5). The second regulating valve (Z2) is arranged between the desulfurized flue gas outlet of the flue gas heat exchanger (4) and the flue gas heat supplement device (6).

3. The sintering flue gas pollutant coordinated carbon removal system according to claim 2 is characterized by: The flue gas reheating device (6) is used to reheat part of the flue gas discharged from the desulfurized flue gas outlet of the flue gas heat exchanger (4), so that the temperature of the flue gas mixed with another part of the flue gas heated by the carbon monoxide catalytic oxidation device (5) reaches above 280°C, the first regulating valve (Z1) is used to regulate the amount of flue gas entering the carbon monoxide catalytic oxidation device (5), and the second regulating valve (Z2) is used to regulate the amount of flue gas entering the flue gas reheating device (6).

4. A sintering flue gas pollutant coordinated carbon removal system according to claim 3, characterized in that: The flue gas heat supplement device (6) is a gas hot air furnace.

5. The sintering flue gas pollutant coordinated carbon removal system according to claim 1 is characterized by: The carbon monoxide catalytic oxidation device (5) is loaded with a precious metal carbon monoxide catalyst, the ammonia injection device (7) is a zoned adjustable ammonia injection device (7), and the volume content of ammonia in the injection medium is less than 5%, the mixing device (8) is a large-scale blade mixer, the SCR denitration reactor (9) is loaded with a medium-temperature denitration catalyst, and the carbon dioxide capture device (10) is a chemical absorption carbon dioxide capture device.

6. A method for synergistic carbon removal of sintering flue gas pollutants using the synergistic carbon removal system for sintering flue gas pollutants as claimed in any one of claims 1 to 5, characterized in that: The method comprises the following steps: The sintering flue gas is passed through a primary dust collector (1) for preliminary dust removal; Passing the flue gas after preliminary dust removal through a desulfurization device (2) for desulfurization; The desulfurized flue gas is passed through a secondary dust collector (3) for dust removal again; The desulfurized flue gas after the dust removal is passed through a flue gas heat exchanger (4) for heat exchange, so that the temperature of the desulfurized flue gas is increased to 250-252° C.; Passing the heated flue gas through a carbon monoxide catalytic oxidation device (5) to oxidize the carbon monoxide in the flue gas into carbon dioxide and release heat, thereby further increasing the flue gas temperature by 28 to 55°C; The flue gas after further heating is sprayed with reducing agent ammonia through an ammonia spraying device (7), and the nitrogen oxides in the flue gas and the reducing agent ammonia are uniformly mixed through a mixing device (8); Passing the uniformly mixed flue gas through an SCR denitration reactor (9) to remove nitrogen oxides in the flue gas, thereby obtaining denitration flue gas whose pollutant particulate matter content, sulfur dioxide content and nitrogen oxide content meet emission standards; The denitrified flue gas is passed through a flue gas heat exchanger (4) for heat exchange and cooling, thereby providing heat for the desulfurized flue gas in the flue gas heat exchanger (4); The flue gas after cooling is passed through a carbon dioxide capture device (10) to capture and remove carbon dioxide in the flue gas.

7. The method for removing sintering flue gas pollutants in a coordinated manner according to claim 6, characterized in that: The method further comprises the following steps: A parallel bypass having a second regulating valve (Z2) and a flue gas heat supplement device (6) is provided for the carbon monoxide catalytic oxidation device (5), and a first regulating valve (Z1) is provided between the desulfurized flue gas outlet of the flue gas heat exchanger (4) and the carbon monoxide catalytic oxidation device (5); Monitoring the flue gas temperature before entering the SCR denitration reactor (9); When it is monitored that the flue gas temperature before entering the SCR denitration reactor (9) reaches above 280°C, the second regulating valve (Z2) and the flue gas reheating device (6) are closed; When it is monitored that the flue gas temperature before entering the SCR denitration reactor (9) has not reached 280°C, the opening of the first regulating valve (Z1) and the opening of the second regulating valve (Z2) are adjusted, thereby respectively adjusting the amount of flue gas entering the carbon monoxide catalytic oxidation device (5) and the amount of flue gas entering the flue gas supplementary heating device (6), and heating the flue gas in the parallel bypass through the flue gas supplementary heating device (6), and mixing the heated flue gas with the flue gas passing through the carbon monoxide catalytic oxidation device (5) and the reducing agent ammonia injected by the ammonia injection device (7) through the mixing device (8), so that the flue gas temperature before entering the SCR denitration reactor (9) reaches above 280°C.

8. The method for removing sintering flue gas pollutants in coordination with carbon according to claim 7, characterized in that: The step of adjusting the opening of the first regulating valve (Z1) and the opening of the second regulating valve (Z2) specifically comprises the following steps: The target temperature of the opening control is set to 280° C., which is the target flue gas temperature before entering the SCR denitration reactor (9); Measuring the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device (5), the carbon monoxide concentration of the flue gas at the outlet of the carbon monoxide catalytic oxidation device (5), and the outlet flue gas temperature; Based on the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device (5), the heat released by the carbon monoxide catalytic oxidation Q and the expected flue gas temperature rise ΔT are calculated by the following calculation formula: p , Q=ΔH·F·(CO in -CO out ); In the formula, ΔH represents the reaction heat of carbon monoxide oxidation, F represents the flue gas flow rate, CO in represents the carbon monoxide concentration of the flue gas at the inlet of the carbon monoxide catalytic oxidation device (5), CO out represents the carbon monoxide concentration of the flue gas at the outlet of the carbon monoxide catalytic oxidation device (5), C p represents the molar heat capacity of flue gas; The feedforward control term FF of the valve opening is calculated by the following formula: FF=K f ·ΔT p ; In the formula, K f represents the feedforward gain coefficient; Calculate the difference between the target temperature and the actual flue gas temperature before entering the SCR denitration reactor (9) as the temperature error e(t); The PID controller is used to calculate the opening fine-tuning control term u1(t) of the first regulating valve (Z1) and the opening fine-tuning control term u2(t) of the second regulating valve (Z2) by the following calculation formula: In the formula, K p1 , K p2 is the proportionality coefficient, K i1 , K i2 is the integration coefficient, K d1 , K d2 is the differential coefficient; The feedforward control term is combined with the opening fine-tuning control term to calculate the final opening of the first regulating valve (Z1) by the following calculation formula: The opening degree Z1 and the final opening degree Z2 of the second regulating valve (Z2), Z1=FF+u1(t); Z2 = 100% - FF + u1 (t); Wherein, the minimum value of Z1 and Z2 is 0, and the maximum value of Z1 and Z2 is 100%.

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