A molecular sieve-based flue gas treatment system and treatment method

Abstract

The present invention provides a flue gas treatment system and a treatment method based on molecular sieve. The system includes: a dust collector, an activated coke adsorption tower, a molecular sieve adsorption tower, a vibrating screen, a regeneration heater, a condenser and a conveying device. The dust collector, the activated coke adsorption tower and the molecular sieve adsorption tower are connected in sequence. The clean flue gas after being adsorbed by the molecular sieve adsorption tower is discharged through a chimney. The molecular sieve in the molecular sieve adsorption tower falls into the vibrating screen to screen out the dust in the molecular sieve, and then enters the regeneration heater for regeneration. The removed moisture enters the condenser for collection. The regenerated molecular sieve is sent back to the molecular sieve adsorption tower through the conveying device. This application removes the activated coke dust carried in the flue gas after being adsorbed by the activated coke, effectively solves the problem of excessive dust in flue gas emissions, and can remove and collect and utilize the moisture in the flue gas.

Description

Technical Field

[0001] The present invention relates to the field of flue gas treatment, and particularly to a flue gas treatment system and method based on molecular sieve. Background Art

[0002] The problems of SO2 and NOx emissions in flue gas are still the main environmental problems. There is also a certain correlation between the frequent haze weather in recent years and the sulfate and nitrate aerosols formed in the atmosphere. In the power industry, the vast majority of units have completed ultra-low emission transformation. In non-electric industries such as steel, coking, cement, and waste incineration, there is also an urgent need to solve the problem of pollutant removal. The water vapor content in the flue gas of coal-fired boilers is usually relatively high (10%), and a large amount of water is wasted due to flue gas discharge. With the country's emphasis on environmental protection, the proportion of gas boilers will gradually increase in the future, and the number of gas industrial boilers will also increase significantly. However, the water vapor content in gas flue gas is even higher (20%), and the amount of water wasted due to flue gas discharge will be even greater. If the moisture in the flue gas is recovered to compensate for the water used in power plants and industrial boilers, the water intake can be significantly reduced, which also means that the recovery of flue gas moisture will be an important technical approach for water conservation and emission reduction in thermal power plants and gas industrial boilers. In the existing technology, the moisture in the flue gas has not been recovered and utilized.

[0003] Activated coke is a porous carbon material mainly produced from coal. As a dry removal technology, the combined removal technology of activated coke has the advantages of integrated desulfurization, denitrification, heavy metal removal, VOCs removal, etc., and can also realize the resource utilization of sulfur, and has been commercially applied in the field of flue gas purification.

[0004] Currently, the core equipment of the combined removal technology using activated coke is the adsorption tower, which is usually arranged behind the dust collector. The dust collector is used to remove dust before the flue gas enters the adsorption tower. However, it is finally found that the dust in the flue gas still exceeds the standard when the flue gas is discharged. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, an embodiment of the present invention provides a flue gas treatment system and method based on molecular sieve, which uses molecular sieve particles to filter the activated coke dust carried in the flue gas, effectively solves the problem of excessive dust, and can also adsorb the moisture in the flue gas.

[0006] The inventors have found through research that after the flue gas is dust-removed and then enters the activated coke adsorption tower for adsorption, since the activated coke desulfurization has a certain adsorption capacity, in order to ensure the adsorption and removal effect, the activated coke needs to be continuously circulated and regenerated inside the adsorption tower. The cyclic wear and thermal regeneration process cause serious loss of activated coke particles, and the surface of the activated coke particles shows a pulverization phenomenon, resulting in the flue gas at the outlet of the adsorption tower carrying activated coke dust and causing the dust content in the flue gas at the outlet of the adsorption tower to exceed the standard again.

[0007] In one aspect of the embodiments of the present invention, a flue gas treatment system based on molecular sieve is proposed, which includes: a dust collector, an activated coke adsorption tower, a molecular sieve adsorption tower, a vibrating screen machine, a regeneration heater and a conveying device. The dust collector has a first flue gas inlet and a first flue gas outlet to remove dust from the flue gas before it enters the activated coke adsorption tower. The activated coke adsorption tower has a second flue gas inlet and a second flue gas outlet. The second flue gas inlet is connected to the first flue gas outlet. An activated coke adsorbent layer is provided inside the activated coke adsorption tower to adsorb pollutants such as SO2 and NOx in the flue gas. The molecular sieve adsorption tower has a third flue gas inlet, a third flue gas outlet, a molecular sieve inlet and a molecular sieve outlet. The third flue gas inlet is connected to the second flue gas outlet. A molecular sieve adsorbent layer is provided inside the molecular sieve adsorption tower. The molecular sieve inlet is connected to the upper end of the molecular sieve adsorbent layer, and the molecular sieve outlet is connected to the lower end of the molecular sieve adsorbent layer. The third flue gas outlet is connected to a chimney to adsorb and remove the activated coke dust and moisture in the flue gas, and the clean flue gas is discharged into the atmosphere through the chimney.

[0008] The vibrating screen machine has a vibrating screen machine inlet and a vibrating screen machine outlet. The vibrating screen machine inlet is connected to the molecular sieve outlet to screen out the dust in the molecular sieve. The regeneration heater has a shell side inlet, a shell side outlet and a water vapor outlet. A heating device is provided inside the regeneration heater. The shell side inlet is connected to the vibrating screen machine outlet to regenerate the molecular sieve. The conveying device has a conveying start end and a conveying end. The conveying start end is arranged below the shell side outlet, and the conveying end is arranged above the molecular sieve inlet to reuse the regenerated molecular sieve.

[0009] In this application, by setting up a molecular sieve adsorption tower, a vibrating screen machine and a regeneration heater, the activated coke dust carried in the flue gas after being adsorbed by the activated coke is removed, effectively solving the problem of excessive dust during flue gas emission, and the moisture in the flue gas can be removed. The scheme is simple, with low cost, and is not limited by the quality of the activated coke.

[0010] In this application, the circulation amount of the molecular sieve in the molecular sieve adsorption tower can be adjusted according to the dust amount at the outlet of the activated coke adsorption tower, with high flexibility, and can adapt to flue gases with various different pollutant components and different pollutant contents.

[0011] In this application, the molecular sieve is heated and regenerated by the regeneration heater, so that the molecular sieve can be recycled, and the adsorbed moisture in the molecular sieve can be removed after heating. Since the molecular sieve has a large water absorption capacity, the number of molecular sieves that need to be heated is small, the consumption of hot flue gas is small, the energy saving for moisture recovery is efficient, and the quality of the recovered moisture is high, which can be reused.

[0012] In some embodiments, the molecular sieve-based flue gas treatment system further includes a condenser, which has a water vapor inlet and a condensed water outlet, and the water vapor inlet is connected to the water vapor outlet.

[0013] By connecting a condenser at the water vapor outlet of the regeneration heater in this application, and utilizing the characteristics of molecular sieve for high-temperature adsorption and dehydration and high reversible regeneration and utilization, the recovery and utilization of moisture in the flue gas can be realized, and the operating cost is low.

[0014] In some embodiments, the heating device is a heating pipe, and a high-temperature medium is introduced into the heating pipe.

[0015] In some embodiments, the high-temperature medium is hot flue gas. The heat of the hot flue gas is used to heat the molecular sieve, so that the hot flue gas is effectively utilized.

[0016] In some embodiments, an induced draft fan is provided on the pipeline connecting the third flue gas outlet of the molecular sieve adsorption tower and the chimney. So that the clean flue gas after adsorption can be quickly discharged into the chimney.

[0017] Another embodiment of the present invention proposes a molecular sieve-based flue gas treatment method, which uses the above-mentioned molecular sieve-based flue gas treatment system, and includes the following steps: the flue gas after being dust-removed by the dust collector enters the activated coke adsorption tower for flue gas purification treatment; the flue gas after being flue gas purification treatment enters the molecular sieve adsorption tower to remove the activated coke dust and moisture in the flue gas, and the clean flue gas is discharged through the chimney; the molecular sieve in the molecular sieve adsorption tower enters the vibrating screen to remove the activated coke dust adsorbed by the molecular sieve, and then the molecular sieve enters the regeneration heater for heating and regeneration, and the regenerated molecular sieve is sent back to the molecular sieve adsorption tower through the conveying device for recycling.

[0018] This application removes the activated coke dust carried in the flue gas after being adsorbed by the activated coke, effectively solves the problem of excessive dust during flue gas emission, and can also remove the moisture in the flue gas. The scheme is simple, the cost is low, and it is not limited by the quality of the activated coke.

[0019] In this application, the molecular sieve is heated and regenerated by the regeneration heater, so that the molecular sieve can be recycled, and the adsorbed moisture in the molecular sieve can be removed after heating. Since the molecular sieve has a large water absorption capacity, the number of molecular sieves that need to be heated is small, the consumption of hot flue gas is small, the energy-saving and high-efficiency of moisture recovery, and at the same time the quality of the recovered moisture is high, and it can be reused.

[0020] In some embodiments, it further includes a condenser, and the moisture in the regeneration heater enters the condenser to be condensed into water for collection.

[0021] This application utilizes the characteristics of molecular sieve for high-temperature adsorption dehydration and highly reversible recycling, enabling the recovery and utilization of moisture in flue gas with low operating costs.

[0022] In some embodiments, the temperature of the flue gas in the molecular sieve adsorption tower is lower than 150°C.

[0023] In some embodiments, the molecular sieve is heated to 200°C - 400°C in the regeneration heater.

[0024] In some embodiments, the diameter of the molecular sieve is greater than or equal to 3 mm, and the compressive strength is greater than or equal to 80 N. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the drawings.

[0026] Wherein:

[0027] Figure 1 is a schematic structural diagram of a flue gas treatment system based on molecular sieve in an embodiment of the present application;

[0028] REFERENCE SIGNS:

[0029] 1 - Dust collector, 2 - Activated coke adsorption tower, 3 - Molecular sieve adsorption tower, 4 - Bunker, 5 - Conveyor, 6 - Induced draft fan, 7 - Chimney, 8 - Condenser, 9 - Regeneration heater, 10 - Vibrating screen, 11 - High-temperature flue gas inlet, 12 - High-temperature flue gas outlet, 13 - Steam outlet pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] The molecular sieve-based flue gas treatment system according to the embodiments of the present invention will be described below with reference to the drawings.

[0032] As Figure 1As shown in the figure, on the one hand, an embodiment of the present application provides a flue gas treatment system based on molecular sieve, including: a dust collector 1, an activated coke adsorption tower 2, a molecular sieve adsorption tower 3, a vibrating screen machine 10, a regeneration heater 9, and a conveying device 5. The dust collector 1 has a first flue gas inlet and a first flue gas outlet to remove dust from the flue gas before it enters the activated coke adsorption tower 2. The activated coke adsorption tower 2 has a second flue gas inlet and a second flue gas outlet. The second flue gas inlet is connected to the first flue gas outlet. An activated coke adsorbent layer is provided inside the activated coke adsorption tower 2 to adsorb pollutants such as SO2 and NOx in the flue gas. The molecular sieve adsorption tower 3 has a third flue gas inlet, a third flue gas outlet, a molecular sieve inlet, and a molecular sieve outlet. The third flue gas inlet is connected to the second flue gas outlet. A molecular sieve adsorbent layer is provided inside the molecular sieve adsorption tower 3. The molecular sieve inlet is connected to the upper end of the molecular sieve adsorbent layer, and the molecular sieve outlet is connected to the lower end of the molecular sieve adsorbent layer. The third flue gas outlet is connected to a chimney 7 to adsorb and remove the activated coke dust and moisture in the flue gas, and the clean flue gas is discharged into the atmosphere through the chimney 7.

[0033] The vibrating screen machine 10 has a vibrating screen machine 10 inlet and a vibrating screen machine 10 outlet. The vibrating screen machine 10 inlet is connected to the molecular sieve outlet to screen out the dust in the molecular sieve. The regeneration heater 9 has a shell side inlet, a shell side outlet, and a steam outlet. A heating device is provided inside the regeneration heater 9. The shell side inlet is connected to the vibrating screen machine 10 outlet to regenerate the molecular sieve. The conveying device 5 has a conveying start end and a conveying end. The conveying start end is arranged below the shell side outlet, and the conveying end is arranged above the molecular sieve inlet to reuse the regenerated molecular sieve.

[0034] By setting the molecular sieve adsorption tower 3, the vibrating screen machine 10, and the regeneration heater 9, the present application removes the activated coke dust carried in the flue gas after activated coke adsorption, effectively solves the problem of excessive dust during flue gas emission, and can also remove the moisture in the flue gas. The solution is simple, with low cost, and is not limited by the quality of activated coke.

[0035] In the present application, the circulation amount of the molecular sieve in the molecular sieve adsorption tower 3 can be adjusted according to the dust amount at the outlet of the activated coke adsorption tower 2, with high flexibility, and it is adaptable to flue gases with various different pollutant components and different pollutant contents.

[0036] The present application heats and regenerates the molecular sieve through the regeneration heater 9, which can make the molecular sieve recycled, and the adsorbed moisture in the molecular sieve can be removed after heating. Since the molecular sieve has a large water absorption capacity, the number of molecular sieves that need to be heated is small, the consumption of hot flue gas is small, the moisture recovery is energy-saving and efficient, and at the same time, the quality of the recovered moisture is high and can be reused.

[0037] In some embodiments, the molecular sieve-based flue gas treatment system further includes a condenser 8, which has a water vapor inlet and a condensate outlet. The water vapor inlet is connected to the water vapor outlet through a steam outlet pipe 13.

[0038] In this application, by connecting the condenser 8 at the water vapor outlet of the regeneration heater 9 and utilizing the characteristics of the molecular sieve to adsorb and dehydrate at high temperature and be highly reversibly regenerated and reused, the recovery and utilization of moisture in the flue gas can be achieved, and the operating cost is low.

[0039] The water molecules adsorbed by the molecular sieve are stored inside the molecular sieve lattice. The molecular sieve is heated to above 200 °C to release the water molecules inside the molecular sieve, and then the water recovery is achieved through the condenser 8.

[0040] In some embodiments, the heating device is a heating pipe, and a high-temperature medium is introduced into the heating pipe.

[0041] In some embodiments, the high-temperature medium is hot flue gas. The heat of the hot flue gas is used to heat the molecular sieve, enabling the effective utilization of the hot flue gas. One end of the heating pipe is a high-temperature flue gas inlet 11, and the other end is a high-temperature flue gas outlet 12.

[0042] In some embodiments, an induced draft fan 6 is provided on the pipeline connecting the third flue gas outlet of the molecular sieve adsorption tower 3 and the chimney 7. The clean flue gas after adsorption is quickly discharged into the chimney 7.

[0043] In some embodiments, the conveying device 5 is a hoist.

[0044] In some embodiments, a feed bin 4 is provided at the top of the molecular sieve adsorption tower 3 for supplying molecular sieve pellets to the inside of the molecular sieve adsorption tower 3. The conveying tail end of the hoist is arranged above the feed bin 4.

[0045] In another embodiment of the present invention, a molecular sieve-based flue gas treatment method is proposed. Using the above-mentioned molecular sieve-based flue gas treatment system, it includes the following steps:

[0046] S1, the flue gas after being dust-removed by the dust collector 1 enters the activated coke adsorption tower 2 for flue gas purification treatment;

[0047] S2, the flue gas after being purified enters the molecular sieve adsorption tower 3 to remove the activated coke dust and moisture in the flue gas, and the clean flue gas is discharged through the chimney 7;

[0048] In S3, after the molecular sieve in the molecular sieve adsorption tower 3 adsorbs dust and moisture for a certain period of time, problems such as an increase in bed resistance and a decrease in the adsorption capacity of the molecular sieve occur. The molecular sieve adsorption tower 3 gradually discharges the molecular sieve pellets, and the molecular sieve pellets enter the vibrating sieve 10 to remove the activated coke dust adsorbed by the molecular sieve. Then, the dedusted molecular sieve enters the regeneration heater 9 and undergoes indirect heat exchange with high-temperature flue gas to achieve the heating regeneration of the molecular sieve, release the moisture in the molecular sieve, and the regenerated molecular sieve is sent back into the molecular sieve adsorption tower 3 through a hoist for recycling.

[0049] This application removes the activated coke dust carried in the flue gas after being adsorbed by the activated coke, effectively solves the problem of excessive dust emissions during flue gas discharge, and can remove the moisture in the flue gas. The scheme is simple, the cost is low, and it is not limited by the quality of the activated coke.

[0050] This application heats and regenerates the molecular sieve through the regeneration heater 9, enabling the molecular sieve to be recycled, and the adsorbed moisture in the molecular sieve can be removed after heating. Since the molecular sieve has a large water absorption capacity, the number of molecular sieves that need to be heated is small, the consumption of hot flue gas is small, the moisture recovery is energy-efficient, and at the same time, the quality of the recovered moisture is high and can be reused.

[0051] In some embodiments, a condenser 8 is further included, and the moisture in the regeneration heater 9 enters the condenser 8 and condenses into water for collection.

[0052] This application utilizes the characteristics of the molecular sieve for high-temperature adsorption and dehydration and high reversible recycling, can realize the recycling of moisture in the flue gas, and has a low operating cost.

[0053] In some embodiments, the temperature of the flue gas in the molecular sieve adsorption tower 3 is lower than 150 °C.

[0054] In some embodiments, the molecular sieve in the regeneration heater 9 is heated to 200 °C to 400 °C.

[0055] In some embodiments, the diameter of the molecular sieve is greater than or equal to 3 mm, and the compressive strength is greater than or equal to 80 N.

[0056] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0057] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0058] In the present invention, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection, an electrical connection, or communicable with each other; it may be directly connected, or indirectly connected through an intermediate medium, and may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention may be understood according to specific circumstances.

[0059] In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0060] In the present invention, terms such as "some embodiments" mean that the specific features, structures, materials or characteristics described in connection with the embodiments are included in at least one embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments in a suitable manner. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments and the features of different embodiments described in this specification.

[0061] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A flue gas treatment system based on molecular sieve, characterized in that, Comprising: A dust collector having a first flue gas inlet and a first flue gas outlet; An activated coke adsorption tower having a second flue gas inlet and a second flue gas outlet, the second flue gas inlet being connected to the first flue gas outlet, and an activated coke adsorbent layer being provided in the activated coke adsorption tower; A molecular sieve adsorption tower having a third flue gas inlet, a third flue gas outlet, a molecular sieve inlet and a molecular sieve outlet, the third flue gas inlet being connected to the second flue gas outlet, a molecular sieve adsorbent layer being provided in the molecular sieve adsorption tower, the molecular sieve inlet being connected to the upper end of the molecular sieve adsorbent layer, the molecular sieve outlet being connected to the lower end of the molecular sieve adsorbent layer, and the third flue gas outlet being connected to a chimney; A vibrating screen machine having a vibrating screen machine inlet and a vibrating screen machine outlet, the vibrating screen machine inlet being connected to the molecular sieve outlet; A regeneration heater having a shell side inlet, a shell side outlet and a steam outlet, a heating device being provided in the regeneration heater, the shell side inlet being connected to the vibrating screen machine outlet; A conveying device having a conveying start end and a conveying end, the conveying start end being provided below the shell side outlet, and the conveying end being provided above the molecular sieve inlet.

2. The molecular sieve-based flue gas treatment system according to claim 1, characterized in that, It further includes a condenser having a steam inlet and a condensate outlet, the steam inlet being connected to the steam outlet.

3. The flue gas treatment system based on molecular sieve according to claim 1, wherein, The heating device is a heating tube, and a high-temperature medium is introduced into the heating tube.

4. The molecular sieve-based flue gas treatment system according to claim 3, wherein, The high-temperature medium is hot flue gas.

5. The flue gas treatment system based on molecular sieve according to claim 1, characterized in that, An induced draft fan is provided on the pipeline connecting the third flue gas outlet of the molecular sieve adsorption tower and the chimney.

6. A flue gas treatment method based on molecular sieve, characterized in that, Using the molecular sieve-based flue gas treatment system according to any one of claims 1-5, comprising the following steps: The flue gas after being dust-removed by the dust collector enters the activated coke adsorption tower for flue gas purification treatment; The flue gas after being subjected to flue gas purification treatment enters the molecular sieve adsorption tower to remove the activated coke dust and moisture in the flue gas, and clean flue gas is obtained and discharged through the chimney; The molecular sieve in the molecular sieve adsorption tower enters the vibrating screen machine to remove the activated coke dust adsorbed by the molecular sieve, and then the molecular sieve enters the regeneration heater for heating and regeneration, and the regenerated molecular sieve is sent back to the molecular sieve adsorption tower through the conveying device for recycling.

7. The method for flue gas treatment based on molecular sieve according to claim 6, wherein It further includes a condenser, and the moisture in the regeneration heater enters the condenser to be condensed into water for collection.

8. The method for flue gas treatment based on molecular sieve according to claim 6, characterized in that, The flue gas temperature in the molecular sieve adsorption tower is lower than 150°C.

9. The method for flue gas treatment based on molecular sieve according to claim 6, characterized in that, The molecular sieve in the regeneration heater is heated to 200°C - 400°C.

10. The method for flue gas treatment based on molecular sieve according to claim 6, wherein, The diameter of the molecular sieve is greater than or equal to 3 mm, and the compressive strength is greater than or equal to 80 N.

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