Heat exchanger with CO2 and H2O adsorption function and sintering flue gas denitration system

Abstract

The utility model relates to a heat exchanger with a CO2 and H2O adsorption function and a sintering flue gas denitration system. The heat exchanger with the CO2 and H2O adsorption function comprises a rotary flue gas heat exchanger consisting of a shell, a rotor and a driving device, the interior of the rotor is divided into a plurality of sectors, the upper layer in each sector is filled with a heat exchange element, the middle layer is filled with a CO2 adsorption material, and the lower layer is filled with an H2O adsorption material; the rotor is divided into an original flue gas side, a purified flue gas side and a desorption area; the rotary flue gas heat exchanger can adsorb water vapor and carbon dioxide in flue gas, so that the volume flow of the flue gas entering the denitration reactor is reduced by 10%-20%, the equipment scale of an SCR denitration system is effectively reduced, meanwhile, the consumption of heating coal gas is reduced, and the engineering investment and operation cost are reduced; in the desorption process of CO2 and H2O, hot flue gas blown into the desorption area is denitrated clean flue gas, so that the inter-leakage of the heat exchanger can be reduced, and the flue gas NOx discharged from the chimney is ensured to reach the standard.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, in particular to a heat exchanger with CO2 and H2O adsorption functions and a sintering flue gas denitration system using the heat exchanger. Background Art

[0002] Existing sintering flue gas treatment generally adopts the process flow of "desulfurization and dust removal first, then denitrification". Among them, the flue gas denitrification system generally adopts SCR denitrification technology with a rotary flue gas heat exchanger. That is, the flue gas after desulfurization and dust removal first enters the raw flue gas side of the rotary flue gas heat exchanger for heat exchange and temperature increase, and then is heated by an external heat source (generally 30-50°C) to the denitrification reaction temperature. Then, under the action of the denitrification catalyst, the NH3-SCR reaction is completed. The flue gas after denitrification enters the clean flue gas side of the rotary flue gas heat exchanger for heat exchange and cooling. The main function of the rotary flue gas heat exchanger is to absorb the heat of the clean flue gas after denitrification to heat the raw flue gas before denitrification. Recovering the heat in the clean flue gas can reduce the gas consumption for external heat source heating (in the SCR denitrification system with a rotary flue gas heat exchanger, the cost of gas consumption for external heat source heating can generally account for more than 40% of the total operating cost of the denitrification system).

[0003] During the sintering process, iron ore, flux, and additives generate large amounts of water vapor and carbon dioxide. Typically, the volumetric content of water vapor in sintering flue gas exceeds 10%, and the volumetric content of carbon dioxide exceeds 5%. These vapor and carbon dioxide, along with other flue gas components, enter the SCR denitrification system. This results in oversized equipment for existing SCR denitrification systems, which in turn leads to high consumption of external heating gas and increased catalyst loading, increasing project investment and operating costs.

[0004] Based on this, the utility model proposes a rotary flue gas heat exchanger with CO2 and H2O adsorption function. The application of this heat exchanger can effectively reduce the equipment scale of the SCR denitrification system and reduce the heating gas consumption, thereby achieving the purpose of reducing project investment and operating costs at the same time. Summary of the Invention

[0005] The utility model provides a heat exchanger with CO2 and H2O adsorption functions and a sintering flue gas denitrification system. The rotary flue gas heat exchanger can adsorb water vapor and carbon dioxide in the flue gas, reducing the volume flow of the flue gas entering the denitrification reactor by 10% to 20%, thereby effectively reducing the equipment scale of the SCR denitrification system, while reducing heating gas consumption, lowering project investment and operating costs; during the CO2 and H2O desorption process, the hot flue gas blown into the desorption zone is clean flue gas with a low NOx concentration after denitrification, which can reduce cross-leakage of the heat exchanger and ensure that the NOx content of the flue gas discharged from the chimney meets the standard.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A heat exchanger with CO2 and H2O adsorption function includes a rotary flue gas heat exchanger consisting of a shell, a rotor and a driving device; the shell is provided with a raw flue gas inlet and a raw flue gas outlet after desulfurization, a clean flue gas inlet and a clean flue gas outlet after denitrification, a desorption gas inlet and a desorption gas outlet; a plurality of radial partitions are arranged inside the rotor to divide the internal space of the rotor into a plurality of sectors, the upper layer of each sector is filled with heat exchange elements, the middle layer is filled with CO2 adsorption material, and the lower layer is filled with H2O adsorption material; according to the different gases passing through the sectors, the rotor is divided into a raw flue gas side, a clean flue gas side and a desorption zone along the circumferential direction; among them, the area connected with the raw flue gas inlet and the raw flue gas outlet after desulfurization is the raw flue gas side, the area connected with the clean flue gas inlet and the clean flue gas outlet after denitrification is the clean flue gas side, and the area connected with the desorption gas inlet and the desorption gas outlet is the desorption zone, and when the rotor rotates, each sector passes through the raw flue gas side, the desorption zone and the clean flue gas side in turn.

[0008] Furthermore, the CO2 adsorption material is a CO2 low-temperature adsorbent.

[0009] Furthermore, the CO2 adsorption material is one or more of carbon-based materials, molecular sieves, metal organic framework materials, and solid amine adsorbents.

[0010] A sintering flue gas denitrification system employs the heat exchanger with CO2 and H2O adsorption function; the sintering flue gas denitrification system is also provided with a gas hot blast furnace, an ammonia supply device, a denitrification reactor and a desorption fan; the raw flue gas outlet of the rotary flue gas heat exchanger is connected to the inlet of the denitrification reactor through a first flue gas duct, and the first flue gas duct is further connected to the gas hot blast furnace and the ammonia supply device; the interior of the denitrification reactor is filled with multiple layers of denitrification catalyst; the outlet of the denitrification reactor is connected to the clean flue gas inlet of the rotary flue gas heat exchanger through a second flue gas duct, and the clean flue gas outlet of the rotary flue gas heat exchanger is connected to the chimney through a third flue gas duct; the inlet of the desorption fan is connected to the second flue gas duct through a duct, and the outlet of the desorption fan is connected to the desorption gas inlet of the rotary flue gas heat exchanger through a duct.

[0011] Compared with the prior art, the beneficial effects of the present invention are:

[0012] 1) The rotary flue gas heat exchanger can adsorb water vapor and carbon dioxide in the flue gas, reducing the flue gas volume flow entering the denitrification reactor by 10% to 20%, thereby effectively reducing the equipment scale of the SCR denitrification system, while reducing heating gas consumption, lowering project investment and operating costs;

[0013] 2) During the desorption process of CO2 and H2O, the hot flue gas blown into the desorption zone is clean flue gas with a low NOx concentration after denitrification, which can reduce the cross-leakage of the heat exchanger and ensure that the NOx of the flue gas emitted from the chimney meets the standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the heat exchanger with CO2 and H2O adsorption function described in Example 1 of the present utility model.

[0015] Figure 2 This is a schematic diagram of the functional area distribution of the heat exchanger with CO2 and H2O adsorption functions described in Example 1 of the present invention.

[0016] Figure 3 This is a schematic diagram of a sintering flue gas denitrification system according to Example 2 of the present invention using the heat exchanger according to Example 1.

[0017] In the figure: 1-rotary flue gas heat exchanger; 101-housing; 102-rotor; 103-driving device; 1011-original flue gas inlet; 1012-original flue gas outlet; 1013-clean flue gas inlet after denitrification; 1014-clean flue gas outlet; 1015-desorption gas inlet; 1016-desorption gas outlet; 1021-heat exchange element; 1022-CO2 adsorption material; 1023-H2O adsorption material; 1024-original flue gas side; 1026-desorption zone; 1025-clean flue gas side; 2-denitrification reactor; 3-gas hot blast furnace; 4-ammonia supply device; 5-desorption fan; L1-first flue gas duct; L2-second flue gas duct; L3-third flue gas duct. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0019] like Figure 1 As shown, the heat exchanger with CO2 and H2O adsorption function described in the present invention includes a rotary flue gas heat exchanger 1 consisting of a shell 101, a rotor 102 and a driving device 103; the shell 101 is provided with a raw flue gas inlet 1011 after desulfurization, a raw flue gas outlet 1012, a clean flue gas inlet 1013 after denitrification, a clean flue gas outlet 1014, a desorption gas inlet 1015 and a desorption gas outlet 1016.

[0020] like Figure 2As shown, a plurality of radial partitions are provided inside the rotor 102 to divide the internal space of the rotor into a plurality of sectors. The upper layer of each sector is filled with heat exchange elements 1021, the middle layer is filled with CO2 adsorption material 1022, and the lower layer is filled with H2O adsorption material 1023. Due to the blocking effect of the radial partition, each sector passes through the air flow separately. According to the different air flows passing through the sectors, the rotor is divided into different functional areas along the circumferential direction, among which: the area connected with the original flue gas inlet 1011 and the original flue gas outlet 1012 after desulfurization is the original flue gas side 1024, the area connected with the clean flue gas inlet 1013 and the clean flue gas outlet 1014 after denitrification is the clean flue gas side 1025, and the area connected with the desorption gas inlet 1015 and the desorption gas outlet 1016 is the desorption zone 1026. The desorption zone 1026 is located between the original flue gas side 1024 and the clean flue gas side 1025. When the rotor rotates, each sector passes through the original flue gas side 1024, the desorption zone 1026 and the clean flue gas side 1025 in turn.

[0021] like Figure 3 As shown, the sintering flue gas denitrification system of the present invention includes the rotary flue gas heat exchanger 1, a denitrification reactor 2, a gas-fired hot blast furnace 3, an ammonia supply device 4, and a desorption fan 5. The raw flue gas outlet 1012 of the rotary flue gas heat exchanger 1 is connected to the inlet of the denitrification reactor 2 via a first flue gas duct L1. The denitrification reactor 2 is loaded with multiple layers of denitrification catalyst. The outlet of the denitrification reactor 2 is connected to the clean flue gas inlet 1013 of the rotary flue gas heat exchanger 1 via a second flue gas duct L2. The clean flue gas outlet 1014 of the rotary flue gas heat exchanger 1 is connected to the chimney via a third flue gas duct L3. The gas-fired hot blast furnace 3 and the ammonia supply device are each connected to the first flue gas duct L1 via a duct. The inlet of the desorption fan 5 is connected to the second flue gas duct L2 via a duct, and the outlet of the desorption fan 5 is connected to the desorption gas inlet 1015 of the rotary flue gas heat exchanger 1 via a duct.

[0022] Preferably, the CO2 adsorption material 1022 of the present invention is a CO2 low-temperature adsorbent composed of one or more substances selected from carbon-based materials, molecular sieves, metal organic framework materials, and solid amine adsorbents, with a CO2 adsorption temperature of 50-100°C and a CO2 desorption temperature of 180-300°C.

[0023] Preferably, the H2O adsorption material 1023 of the present invention is a molecular sieve or activated carbon material loaded with one or more of CaCl2, CuSO4, MgSO4, Na2CO3, KAl(SO4)2, ZnSO4, FeSO4, and Co(ClO4)2. At temperatures between 50 and 100°C, the loaded substance absorbs water vapor in the flue gas to form hydrates. At temperatures between 180 and 300°C, the hydrates decompose and dehydrate.

[0024] The utility model discloses a sintering flue gas denitrification method, which includes the following steps:

[0025] 1. CO2 and H2O adsorption process;

[0026] The desulfurized flue gas enters the raw flue gas side 1024 of the rotary flue gas heat exchanger 1 through the raw flue gas inlet 1011. The gaseous water in the flue gas is adsorbed by the H2O adsorption material 1023. Under the condition of 50-100°C, the substance loaded by the H2O adsorption material 1023 absorbs the water vapor in the flue gas to form a hydrate. Taking CaCl2 as an example, the chemical reaction that occurs is:

[0027] CaCl2+6H2O=CaCl2·6H2O

[0028] The flue gas after water vapor is absorbed and removed flows through the CO2 adsorption material 1022, and the carbon dioxide in the flue gas is adsorbed and removed. The CO2 adsorption material 1022 is a CO2 low-temperature adsorbent, with a CO2 adsorption temperature of 50-100°C and a CO2 desorption temperature of 180-300°C.

[0029] The flue gas first absorbs and removes water vapor, and then absorbs and removes carbon dioxide. The main reason is that after the water vapor in the flue gas is reduced, the competitive adsorption of water molecules and carbon dioxide molecules on the CO2 adsorption material 1022 can be reduced, the carbon dioxide capture efficiency can be improved, and the risk of pore blockage can be reduced.

[0030] After flowing through the H2O adsorption material 1023 and the CO2 adsorption material 1022, water vapor and carbon dioxide in the flue gas are adsorbed and removed, and the flue gas volume flow rate can be reduced by 10% to 20%.

[0031] 2. NOx removal process;

[0032] After the water vapor and carbon dioxide have been adsorbed, the flue gas is heated by heat exchange element 1021 and enters the first flue gas duct L1 through raw flue gas outlet 1012. The gas hot blast furnace 3 generates hot gas at a temperature of 800-1000°C, which enters the first flue gas duct L1. The flue gas is heated to the denitration reaction temperature of 180-300°C. The ammonia supply device 4 adds gaseous NH3 to the first flue gas duct L1. The flue gas and NH3 are evenly mixed and then enter the denitration reactor 2. Under the action of the denitration catalyst, NOx in the flue gas reacts with NH3, completing the flue gas denitration process.

[0033] The flue gas after denitrification enters the clean flue gas side 1025 of the rotary flue gas heat exchanger 1 through the second flue gas duct L2 and the clean flue gas inlet 1013, recovers heat through the heat exchange element 1021 and is cooled, and passes through the CO2 adsorption material 1022 and the H2O adsorption material 1023 again, and is then sent to the chimney for discharge through the third flue gas duct L3.

[0034] 3. CO2 and H2O desorption process;

[0035] After the adsorption reaction on the raw flue gas side 1024, the CO2 adsorbent material 1022 and H2O adsorbent material 1023 rotate with the rotor into the desorption zone 1026. The desorption blower 5 blows the hot flue gas at a temperature of 180-300°C from the second flue gas duct L2 into the desorption gas inlet 1015. Under the action of the high-temperature hot flue gas, the CO2 adsorbent material 1022 and H2O adsorbent material 1023 are heated and regenerated. The desorbed CO2 and H2O are discharged along with the desorption gas through the desorption gas outlet 1016 and sent to the CO2 separation device for purification and comprehensive utilization.

[0036] In the desorption zone 1026, under the condition of 180-300°C, the hydrate in the H2O adsorption material 1023 decomposes and dehydrates, completing the desorption. Taking CaCl2 as an example, the chemical reaction that occurs is:

[0037] CaCl2·6H2O=CaCl2+6H2O

[0038] During this process, the hot flue gas blown into the desorption zone 1026 by the desorption fan 5 can achieve the following functions:

[0039] (1) The CO2 adsorption material 1022 and the H2O adsorption material 1023 are heated and regenerated, and the desorbed carbon dioxide and water vapor are sent to the CO2 separation device for comprehensive utilization after purification.

[0040] (2) Under the blocking effect of multiple radial partitions inside the rotor 102, air flows through each sector separately, and the clean flue gas after denitrification is blown into the sector of the desorption zone 1026, forming a positive pressure cavity, thereby preventing the flue gas with a high NOx concentration in the original flue gas side 1024 from leaking to the clean flue gas side 1025, and ensuring that the NOx content in the exhaust gas discharged through the chimney meets the standard.

[0041] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with the examples. The following examples are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the scope of protection of the present invention.

[0042] [Example 1]

[0043] Reference Figure 1 、 Figure 2 In this embodiment, the heat exchanger with CO2 and H2O adsorption function is a rotary flue gas heat exchanger 1 composed of a shell 101, a rotor 102 and a driving device 103.

[0044] In this embodiment, the bottom of the housing 101 is provided with a desulfurized raw flue gas inlet 1011, a clean flue gas outlet 1014, and a desorbed gas outlet 1016. The top of the housing 101 is provided with a raw flue gas outlet 1012, a denitrified clean flue gas inlet 1013, and a desorbed gas inlet 1015. Multiple radial partitions are provided within the rotor 102, dividing the rotor into 36 sectors. Within each sector, the upper layer is filled with heat exchange elements 1021, the middle layer is filled with CO2 adsorption material 1022, and the lower layer is filled with H2O adsorption material 1023.

[0045] Due to the blocking effect of the radial partition, air flows through each sector separately. According to the different air flows passing through the sectors, the rotor is divided into different functional areas, among which: the area connected with the original flue gas inlet 1011 and the original flue gas outlet 1012 after desulfurization is the original flue gas side 1024, the area connected with the clean flue gas inlet 1013 and the clean flue gas outlet 1014 after denitrification is the clean flue gas side 1025, and the area connected with the desorption gas inlet 1015 and the desorption gas outlet 1016 is the desorption zone 1026. The desorption zone 1026 is located between the original flue gas side 1024 and the clean flue gas side 1025. The rotor rotates cyclically through the original flue gas side 1024, the desorption zone 1026 and the clean flue gas side 1025 in turn.

[0046] [Example 2]

[0047] Reference Figure 3 In this embodiment, the sintering flue gas denitrification system includes the rotary flue gas heat exchanger 1 in Example 1, and also includes a denitrification reactor 2, a gas hot blast furnace 3, an ammonia supply device 4 and a desorption fan 5.

[0048] The original flue gas outlet 1012 of the rotary flue gas heat exchanger 1 is connected to the inlet of the denitration reactor 2 through the first flue gas duct L1. Three layers of denitration catalyst are loaded inside the denitration reactor 2. The outlet of the denitration reactor 2 is connected to the clean flue gas inlet 1013 of the rotary flue gas heat exchanger 1 through the second flue gas duct L2. The clean flue gas outlet 1014 of the rotary flue gas heat exchanger 1 is connected to the third flue gas duct L3.

[0049] The gas hot blast furnace 3 and the ammonia supply device 4 are connected to the first flue gas duct L1 via pipes. The inlet of the desorption fan 5 is connected to the second flue gas duct L2 via pipes, and the outlet of the desorption fan 5 is connected to the desorption gas inlet 1015 of the rotary flue gas heat exchanger 1 via pipes.

[0050] In this embodiment, the CO2 adsorption material 1022 is a CO2 low-temperature adsorbent composed of a carbon-based material and a molecular sieve, the CO2 adsorption temperature is 50-100°C, and the CO2 desorption temperature is 180-300°C.

[0051] In this embodiment, the H2O adsorption material 1023 is an activated carbon material loaded with CaCl2, MgSO4, Na2CO3, and FeSO4. Under the condition of 50-100°C, the loaded substances absorb water vapor in the flue gas to form hydrates. Under the condition of 180-300°C, the hydrates decompose and dehydrate.

[0052] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any technician familiar with the technical field within the technical scope disclosed by the present invention can make equivalent replacements or changes based on the technical solution and utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A heat exchanger with CO2 and H2O adsorption function, comprising a rotary flue gas heat exchanger consisting of a housing, a rotor and a drive device; characterized in that: The shell is provided with an inlet for raw flue gas after desulfurization, an outlet for raw flue gas, an inlet for clean flue gas after denitrification, a clean flue gas outlet, an inlet for desorbed gas, and an outlet for desorbed gas; a plurality of radial partitions are provided inside the rotor to divide the internal space of the rotor into a plurality of sectors, and the upper layer of each sector is filled with heat exchange elements, the middle layer is filled with CO2 adsorption material, and the lower layer is filled with H2O adsorption material; According to the different gases passing through the sectors, the rotor is divided into the original flue gas side, the clean flue gas side and the desorption zone along the circumferential direction; among them, the area connected with the original flue gas inlet and the original flue gas outlet after desulfurization is the original flue gas side, the area connected with the clean flue gas inlet and the clean flue gas outlet after denitrification is the clean flue gas side, and the area connected with the desorption gas inlet and the desorption gas outlet is the desorption zone. When the rotor rotates, each sector passes through the original flue gas side, the desorption zone and the clean flue gas side in turn.

2. A heat exchanger with CO2 and H2O adsorption function according to claim 1, characterized in that: The CO2 adsorption material is a CO2 low-temperature adsorbent.

3. A heat exchanger with CO2 and H2O adsorption function according to claim 1 or 2, characterized in that: The CO2 adsorption material is one or more of a carbon-based material, a molecular sieve, a metal organic framework material, and a solid amine adsorbent.

4. A sintering flue gas denitrification system, characterized in that: A heat exchanger with CO2 and H2O adsorption function as described in any one of claims 1 to 3 is applied; the sintering flue gas denitrification system is also provided with a gas hot blast furnace, an ammonia supply device, a denitrification reactor and a desorption fan; the raw flue gas outlet of the rotary flue gas heat exchanger is connected to the inlet of the denitrification reactor through a first flue gas duct, and the first flue gas duct is also connected to the gas hot blast furnace and the ammonia supply device; the interior of the denitrification reactor is filled with multiple layers of denitrification catalyst; the outlet of the denitrification reactor is connected to the clean flue gas inlet of the rotary flue gas heat exchanger through a second flue gas duct, and the clean flue gas outlet of the rotary flue gas heat exchanger is connected to the chimney through a third flue gas duct; the inlet of the desorption fan is connected to the second flue gas duct through a duct, and the outlet of the desorption fan is connected to the desorption gas inlet of the rotary flue gas heat exchanger through a duct.

Images