Condensable particulate matter efficient removal system and method based on low-temperature condensation coupling adsorption

Abstract

The invention belongs to the field of pollutant control, and particularly discloses a low-temperature condensation coupling adsorption condensable particulate matter efficient removal system and method.The system comprises a low-temperature condensation unit and a heat-carrying adsorption unit, the adsorption device is used for adsorbing condensable particulate matters in the to-be-treated flue gas to form a liquid condensate; the heat-carrying adsorption unit comprises an adsorption chamber as well as an induced draft fan, a heat carrier and an adsorbent layer which are sequentially arranged in the adsorption chamber from bottom to top, and a flue gas inlet of the adsorption chamber is formed between the induced draft fan and the heat carrier and is used for feeding the condensed flue gas into the adsorption chamber and enabling the flue gas to flow upwards under the driving of the induced draft fan; after being heated by the heat carrier, the flue gas is conveyed to the adsorbent layer, so that the condensable particulate matter precursor in the heated flue gas is adsorbed by using an adsorbent. According to the application, comprehensive removal of the condensable particulate matters can be realized by utilizing low-temperature condensation coupling adsorption, so that the emission control effect of the condensable particulate matters is further improved.

Description

Technical Field

[0001] The present application belongs to the field of pollutant control, and more specifically, to a system and method for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption. Background Art

[0002] Pollutants emitted during the coal combustion process are one of the important causes of severe air pollution in my country. In recent years, my country has made major breakthroughs in the theory and technology of pollutant removal from coal-fired stationary sources. Conventional pollutants, such as filterable particulate matter, sulfur dioxide, and nitrogen oxides, have been reduced to less than 10 mg / m 3 , 35mg / m 3 and 50 mg / m 3 Ultra-low emission standards. Condensable particulate matter is defined as liquid or solid particulate matter (generally <2.5μm) that is in a gaseous state in the flue and is discharged into the atmosphere through cooling, condensation or reaction to form. Due to its complex formation mechanism, condensable particulate matter contains a wealth of harmful substances, mainly inorganic components such as SO3 and organic components such as hydrocarbons, which seriously endanger the natural environment and human health. Studies have shown that the actual emission concentration of condensable particulate matter from fixed sources far exceeds the emission standards for filterable particulate matter. At present, the proportion of condensable particulate matter discharged into the atmosphere is higher than that of filterable particulate matter.

[0003] Existing particulate matter control technologies can be divided into two categories: joint control and adsorption removal. Both are developed for filterable particulate matter, and can only achieve synergistic removal for condensable particulate matter. Among them, joint control includes electrostatic precipitator, bag filter, wet desulfurization device, etc., which mainly relies on load charge, inertial filtration, spray slurry and other methods to remove filterable particulate matter with larger particle size, and the removal efficiency of condensable particulate matter is limited; adsorption removal, such as activated carbon adsorption, has low removal efficiency for condensable particulate matter. Existing studies have shown that at 90°C, the adsorption removal efficiency of activated carbon for condensable particulate matter is only 19-22%. Due to the huge differences in chemical composition and physical form between condensable particulate matter and filterable particulate matter, the existing particulate matter control technology has a low removal efficiency for condensable particulate matter, and it is urgent to develop emission control technology specifically for condensable particulate matter.

[0004] In the prior art, CN115715921A discloses a highly efficient removal device and method for condensable particulate matter in a coal-fired power plant. The patent adopts an absorption solution spray to reduce the generation of SO3 at the SCR to achieve the removal of condensable particulate matter. However, the removal device is located at the front end of the combined pollution control device, and the generation and control of other components of condensable particulate matter in the combined removal process are not considered. CN113144867A discloses a system and method for efficient removal of fine particulate matter in conjunction with flue gas desulfurization. The system adopts the recycling of spray slurry to form particle agglomerates to achieve the removal of fine particulate matter in coal-fired power plants. However, the removal strategy of the patent does not consider the pollution problems that may be caused by the desulfurization slurry being discharged into the atmosphere with the flue gas. CN111632764A discloses a highly efficient cooling coupled pre-charged SO3 enhanced agglomeration device and method thereof. The patent adopts cooling and charging to remove SO3 to achieve the reduction of blue smoke plume emissions from coal-fired power plants. However, the removal objects in this patent document are only for some gaseous precursors of condensable particulate matter, and the removal efficiency for other condensable particulate matter precursors is low, and the actual emission capacity of the flue gas after cooling is not considered. Summary of the invention

[0005] In view of the defects of the prior art, the present application provides a system and method for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption, aiming to solve the problem that the existing particulate matter control devices can only achieve collaborative removal of condensable particulate matter and the removal efficiency is not high.

[0006] According to one aspect of the present application, a system for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption is provided, which specifically comprises a low-temperature condensation unit and a heat carrier adsorption unit, wherein:

[0007] The low-temperature condensation unit is used to construct a supersaturated steam environment, so that water vapor condenses with ultrafine particles as nuclei to form embryo droplets, so as to adsorb condensable particles in the flue gas to be treated to form liquid condensate, and the flue gas after condensation treatment is sent to the heat-carrying adsorption unit;

[0008] The heat carrier adsorption unit includes an adsorption chamber and an induced draft fan, a heat carrier and an adsorbent layer which are sequentially arranged inside the adsorption chamber from bottom to top. The flue gas inlet of the adsorption chamber is opened between the induced draft fan and the heat carrier, and is used to send the flue gas after condensation treatment into the adsorption chamber, and flow upward under the drive of the induced draft fan, and then be sent to the adsorbent layer after being heated by the heat carrier, so as to use the adsorbent to adsorb the condensable particulate matter precursors in the heated flue gas, and finally directly discharge the flue gas after adsorption treatment.

[0009] Through the above technical scheme conceived by the present application, compared with the prior art, the present application can efficiently remove various types of condensable particulate matter including inorganic components and organic components by setting up a low-temperature condensation unit and a heat carrier adsorption unit, and the treated flue gas can be directly discharged.

[0010] As further preferred, the low-temperature condensation unit includes a condensation chamber, at least one water mist generator and at least one heat exchanger, the condensation chamber having a smoke inlet at the left end and a smoke outlet at the right end and connected to the adsorption chamber through a smoke duct; each of the water mist generators is arranged at intervals along the smoke flow direction at the top of the condensation chamber and connected to the heat exchanger, for providing condensed water or steam to the condensation chamber to construct a supersaturated steam environment.

[0011] As a further preferred embodiment, the efficient removal system of condensable particulate matter also includes a liquid storage unit, which includes at least one liquid storage tank, each of which is arranged at intervals along the flue gas flow direction and is respectively connected to the low-temperature condensation unit for collecting liquid condensate from the low-temperature condensation unit.

[0012] As further preferred, the low-temperature condensation unit further includes at least one liquid accumulation plate, each of which is arranged inside the condensation chamber at intervals along the flue gas flow direction, and the liquid accumulation plate is arranged below the flue gas inlet for collecting liquid condensate.

[0013] As further preferred, the spray angle of the water mist generator is 45° to 135°.

[0014] As a further preferred embodiment, the surface of the effusion plate is opened with a porosity of 25% to 45%, an inclination angle of the holes is 30° to 60°, and a hole diameter of the holes is 10 mm to 30 mm.

[0015] As a further preference, the diameter of the condensation chamber gradually decreases from top to bottom, and the diameter of the adsorption chamber gradually increases from top to bottom.

[0016] As further preferred, the adsorbent is a sodium-based adsorbent, a calcium-based adsorbent, a magnesium-based adsorbent or activated carbon.

[0017] As further preferred, the heat carrier adsorption unit further comprises an air volume regulating component, which is connected to the induced draft fan and is used to regulate the air flow rate of the induced draft fan according to the temperature and flow rate of the adsorption chamber.

[0018] According to another aspect of the present application, a method for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption is provided. The method adopts the above-mentioned efficient removal system for condensable particulate matter, specifically: the flue gas is sent into a low-temperature condensation unit, and water vapor is used to condense ultrafine particles as nuclei to form embryo droplets, thereby adsorbing the condensable particulate matter in the flue gas to be treated, and the flue gas after condensation treatment is sent to a heat-carrying adsorption unit for heating, and discharged after adsorption by an adsorbent.

[0019] In general, the above technical solutions conceived by this application have the following technical advantages compared with the prior art:

[0020] 1. The present application provides a system specifically for removing condensable particulate matter, wherein by setting a low-temperature condensation unit and a heat carrier adsorption unit, the low-temperature condensation coupled adsorption can be used to achieve comprehensive removal of condensable particulate matter. In addition to SO3 and various inorganic salts, which are important components of condensable particulate matter, the removal objects also include organic components of condensable particulate matter such as hydrocarbons, lipids, and desulfurization slurry remaining during actual smoke exhaust, thereby further improving the emission control effect of condensable particulate matter, and using a heat carrier to heat the condensed flue gas, it can be directly discharged into the atmosphere;

[0021] 2. At the same time, the present application can collect the liquid condensate in the low-temperature condensation unit by setting up a liquid storage unit to realize the reuse of water resources, thereby achieving water-saving effect;

[0022] 3. In addition, the present application can further improve the removal effect of condensable particulate matter by optimizing the parameters of each component in the low-temperature condensation unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the efficient removal system of condensable particulate matter by low-temperature condensation coupled adsorption provided in an embodiment of the present application.

[0024] Throughout the drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0025] 1-heat exchanger, 2-water mist generator, 3-condensation chamber, 4-liquid accumulation plate, 5-sensing valve, 6-liquid storage tank, 7-flue gas duct, 8-induced draft fan, 9-heat carrier, 10-adsorbent conveyor belt, 11-air volume adjustment component, 12-adsorption chamber. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0027] like Figure 1 As shown, the present application provides a system for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption, which specifically includes a low-temperature condensation unit and a heat carrier adsorption unit, wherein:

[0028] The low-temperature condensation unit is used to construct a supersaturated steam environment, so that water vapor condenses with ultrafine particles as nuclei to form embryo droplets, thereby adsorbing condensable particles in the flue gas to be treated to form liquid condensate, and the condensed flue gas is sent to the heat-carrying adsorption unit;

[0029] The heat carrier adsorption unit includes an adsorption chamber 12 and an induced draft fan 8, a heat carrier 9 and an adsorbent layer 10 which are sequentially arranged inside the adsorption chamber 12 from bottom to top. The flue gas inlet of the adsorption chamber 12 is opened between the induced draft fan 8 and the heat carrier 9 to send the condensed flue gas into the adsorption chamber 12, and flow upward under the drive of the induced draft fan 8, and be sent to the adsorbent layer 10 after being heated by the heat carrier 9, so as to utilize the adsorbent to adsorb the condensable particulate matter precursors in the heated flue gas, and finally discharge the adsorbed flue gas directly into the atmosphere. The heat carrier adsorption unit heats the condensed flue gas, and while removing the residual pollutants in the flue gas, the flue gas temperature is increased, so that the flue gas has an autonomous upward momentum and is smoothly discharged into the atmosphere.

[0030] Specifically, the induced draft fan 8 is used to provide dry air to mix the flue gas after condensation with the dry air and provide upward momentum for it. The specific number of the induced draft fans 8 can be determined according to the actual flue gas volume. When multiple induced draft fans are provided according to actual needs, the connection mode between the multiple induced draft fans can be set to parallel; the heat carrier 9 is used to provide thermal energy to provide thermal energy for heating the flue gas after condensation, and at the same time heat the adsorbent to activate it, thereby improving the adsorption capacity of the adsorbent; the adsorbent layer 10 can be provided with a conveyor belt for transporting the adsorbent to ensure that the adsorbent is always in motion, so that the flue gas and the adsorbent contact and react with each other, so as to increase the contact area between the adsorbent and the flue gas, and fully adsorb the organic components and possible residual slurry in the condensable particulate matter remaining in the flue gas.

[0031] In view of the problem that existing particulate matter control devices can only achieve synergistic removal of condensable particulate matter and have poor control effects, the present application proposes a high-efficiency removal system specifically for condensable particulate matter, which fills the current technical gap. By setting a low-temperature condensation unit and a heat carrier adsorption unit, the removal objects include not only SO3 and various inorganic salts, which are important components of condensable particulate matter, but also organic components of condensable particulate matter such as hydrocarbons, lipids and desulfurization slurry remaining during actual smoke exhaust. The supersaturated steam environment constructed by the low-temperature condensation unit allows water vapor to condense with ultrafine particles as nuclei to form embryo droplets, which will achieve effective adsorption of SO3 and various inorganic salts in the above-mentioned objects; the adsorbent is activated by heating the adsorbent, so as to achieve removal of hydrocarbons, lipids, and desulfurization slurry remaining during actual smoke exhaust, thereby achieving efficient removal of condensable particulate matter. In practical applications, the low-temperature condensation coupled adsorption condensable particulate matter efficient removal system provided in the present application can be set at the very end of the flue gas treatment system of a power plant, and the condensable particulate matter can be efficiently removed separately before the flue gas is discharged, effectively solving the current problem of high condensable particulate matter emissions.

[0032] Furthermore, the low-temperature condensation unit includes a condensation chamber 3, at least one water mist generator 2 and at least one heat exchanger 1, wherein: the condensation chamber 3 is used to provide a space for mixing and condensing the flue gas and the condensing steam, the left end of the condensation chamber 3 is provided with a flue gas inlet, the right end is provided with a flue gas outlet and is connected to the adsorption chamber 12 through a flue gas duct 7, so that the flue gas flows from left to right in the condensation chamber 3, thereby effectively increasing the residence time of the flue gas in the condensation chamber 3, ensuring that the condensable particles in the flue gas can fully contact with the embryo droplets, so as to increase the condensable particles. The removal rate of particulate matter; each water mist generator 2 is arranged at intervals along the direction of flue gas flow at the top of the condensation chamber 3 and connected to the heat exchanger 1, which is used to provide condensed water or steam to the condensation chamber 12 to construct a supersaturated steam environment, so that the saturated steam value of the condensation chamber 12 is stabilized at 1.1-1.2, and the heat exchanger 1 is used to accurately adjust the temperature of the liquid sprayed by the water mist generator 2, wherein the temperature of the condensed water is preferably 30°C-50°C, so as to achieve the effect of synergistic removal of multiple pollutants, and the spray angle of the water mist generator 2 is 45°-135°. The water mist generator 2 is provided with an electronic flow regulating valve with adjustable spray amount, and the steam generation flow rate of the water mist generator 2 can be determined according to the actual flue gas volume. The specific number of water mist generators 2 can be determined according to the actual flue gas volume. The water mist generator 2 is arranged at the top of the condensation chamber 3, and the spray direction of its nozzle can be downward or along the flue gas flow, or other spray angles between the two, and the nozzle can be a pressure atomization nozzle or a dual-fluid atomization nozzle.

[0033] Preferably, a plurality of sets of parallel temperature detectors and humidity detectors are provided inside the condensation chamber 3, and the temperature detectors and humidity detectors are connected to the water mist generator 2 and the heat exchanger 1 through a control module to adjust the saturated steam value of the condensation chamber 12 and the temperature of the liquid sprayed by the water mist generator 2 in real time.

[0034] Furthermore, the efficient removal system for condensable particulate matter also includes a liquid storage unit, which includes at least one liquid storage tank 6. Each liquid storage tank 6 is arranged at intervals along the direction of flue gas flow and is respectively connected to the condensation chamber 3 to collect liquid condensate in the condensation chamber 3. The liquid condensate can be sent back to the water mist generator 2 for secondary use to achieve the reuse of water resources. The specific number of condensate storage tanks 6 and sensing valves 5 can be determined according to the actual amount of liquid condensate generated. When multiple liquid storage tanks 6 are provided in the liquid storage unit according to actual needs, the connection mode between the multiple liquid storage tanks 6 can be set to parallel. In this parallel mode, the opening and closing of different liquid storage tanks 6 can be determined according to actual needs. When a fault occurs and maintenance is performed, only the corresponding liquid storage tank 6 needs to be closed, which does not affect the operation of the entire system and has a high fault tolerance rate.

[0035] Preferably, a sensing valve 5 is provided between the liquid storage tank 6 and the condensation chamber 3. The sensing valve 5 is used to quantitatively transport liquid condensate to the liquid storage tank 6. During operation, the sensing valve 5 is in a normally closed state. When the liquid condensate in the condensation chamber 3 accumulates to a certain weight, the sensing valve 5 opens and transports the liquid condensate to the liquid storage tank 6. The weight sensing value of the sensing valve 5 is 1 / 4 to 1 / 5 of the storage capacity of the liquid storage tank.

[0036] Further, the low-temperature condensation unit also includes at least one liquid accumulation plate 4, each of which is arranged in the condensation chamber 3 at intervals along the flue gas flow direction, and the liquid accumulation plate 4 is arranged below the flue gas inlet for collecting liquid condensate. The surface of the liquid accumulation plate 4 is perforated, the porosity is 25% to 45%, the inclination angle of the hole is 30° to 60°, and the aperture of the hole is 10mm to 30mm. The liquid accumulation plate 4 can make the flue gas distribution more uniform, drive the airflow to the central area of ​​the condensation chamber 3, reduce the scouring of the wall by the spray, and improve the deviation phenomenon. The spray is from top to bottom, forming a certain liquid film height on the liquid accumulation plate 4, and the flue gas passes through the liquid holding layer on the multi-liquid plate 4 from top to bottom, which increases the gas-liquid contact time. The parameter settings of the porosity, aperture, and inclination angle will affect the formation of the liquid accumulation layer. By optimizing the above three parameters, the liquid holding layer on the liquid accumulation plate 4 can be guaranteed to be stable and of moderate height.

[0037] Furthermore, the diameter of the condensation chamber 3 gradually decreases from top to bottom, so that the liquid condensate can more conveniently gather at the bottom by inertia or gravity, which is convenient for collecting the liquid condensate; the diameter of the adsorption chamber 12 gradually increases from top to bottom, so as to better fit the shape of the chimney flue, and the adsorption chamber 12 can be set in the chimney during operation.

[0038] Furthermore, the heat carrier 9 includes one or more constant temperature heating elements placed in parallel, and the temperature of the heat carrier 9 is maintained at 130°C to 150°C.

[0039] Furthermore, the adsorbent is a sodium-based adsorbent, a calcium-based adsorbent, a magnesium-based adsorbent or activated carbon, so that it can adsorb a variety of condensable particulate matter precursors including inorganic components and organic components. The adsorbent layer 10 is made of corrosion-resistant material to improve its stability.

[0040] Furthermore, the heat carrier adsorption unit also includes an air volume regulating component, which is arranged at the outlet position of the adsorption chamber 12 and connected to the induced draft fan 8, and is used to adjust the power of the induced draft fan 8 according to the temperature and flow of the adsorption chamber 12 to adjust the air supply flow.

[0041] According to another aspect of the present application, a method for efficiently removing condensable particulate matter by low-temperature condensation coupled with adsorption is provided. The method adopts the above-mentioned efficient removal system for condensable particulate matter, specifically: the flue gas is sent into a low-temperature condensation unit, and water vapor is used to condense ultrafine particles as nuclei to form embryo droplets, thereby adsorbing the condensable particulate matter in the flue gas to be treated, and the flue gas after condensation treatment is sent to a heat-carrying adsorption unit for heating, and discharged after adsorption by an adsorbent.

[0042] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A low-temperature condensation coupled adsorption system for efficient removal of condensable particles, characterized in that: It includes a low temperature condensation unit and a heat carrier adsorption unit, wherein: The low-temperature condensation unit is used to construct a supersaturated steam environment, so that water vapor condenses with ultrafine particles as nuclei to form embryo droplets, so as to adsorb condensable particles in the flue gas to be treated to form liquid condensate, and the flue gas after condensation treatment is sent to the heat-carrying adsorption unit; The heat carrier adsorption unit comprises an adsorption chamber (12) and an induced draft fan (8), a heat carrier (9) and an adsorbent layer (10) which are sequentially arranged inside the adsorption chamber (12) from bottom to top. The flue gas inlet of the adsorption chamber (12) is opened between the induced draft fan (8) and the heat carrier (9) for sending the flue gas after condensation treatment into the adsorption chamber (12), and flowing upward under the drive of the induced draft fan (8), and then being sent to the adsorbent layer (10) after being heated by the heat carrier (9), so as to use the adsorbent to adsorb the condensable particulate matter precursor in the heated flue gas, and finally directly discharge the flue gas after adsorption treatment.

2. The system for efficiently removing condensable particulate matter according to claim 1, characterized in that: The low-temperature condensation unit comprises a condensation chamber (3), at least one water mist generator (2) and at least one heat exchanger (1); the condensation chamber (3) has a smoke inlet at the left end and a smoke outlet at the right end and is connected to an adsorption chamber (12) via a smoke duct (7); each of the water mist generators (2) is arranged at intervals at the top of the condensation chamber (3) along the direction of smoke flow and is connected to the heat exchanger (1) for providing condensed water or steam to the condensation chamber (12) to construct a supersaturated steam environment.

3. The system for efficiently removing condensable particulate matter according to claim 1, characterized in that: The high-efficiency removal system for condensable particulate matter also includes a liquid storage unit, which includes at least one liquid storage tank (6), each of which is arranged at intervals along the flue gas flow direction and is respectively connected to a low-temperature condensation unit for collecting liquid condensate from the low-temperature condensation unit.

4. The system for efficiently removing condensable particulate matter according to claim 1, characterized in that: The low-temperature condensation unit further comprises at least one liquid accumulation plate (4), each of the liquid accumulation plates (4) being arranged inside the condensation chamber (3) at intervals along the flue gas flow direction, and the liquid accumulation plates (4) being arranged below the flue gas inlet for collecting liquid condensate.

5. The system for efficiently removing condensable particulate matter according to claim 2, characterized in that: The spray angle of the water mist generator (2) is 45° to 135°.

6. The system for efficiently removing condensable particulate matter according to claim 4, characterized in that: The surface of the liquid accumulation plate (4) is perforated, the perforation rate is 25% to 45%, the inclination angle of the holes is 30° to 60°, and the hole diameter is 10 mm to 30 mm.

7. The system for efficiently removing condensable particulate matter according to claim 2, characterized in that: The diameter of the condensation chamber (3) gradually decreases from top to bottom, and the diameter of the adsorption chamber (12) gradually increases from top to bottom.

8. The system for efficiently removing condensable particulate matter according to claim 1, characterized in that: The adsorbent is a sodium-based adsorbent, a calcium-based adsorbent, a magnesium-based adsorbent or activated carbon.

9. The system for efficiently removing condensable particulate matter according to any one of claims 1 to 8, characterized in that: The heat-carrying adsorption unit further comprises an air volume regulating component, wherein the air volume regulating component (11) is connected to the induced draft fan (8) and is used to regulate the air flow rate of the induced draft fan (8) according to the temperature and flow rate of the adsorption chamber (12).

10. A method for efficiently removing condensable particles by low-temperature condensation coupled with adsorption, characterized in that: The method for efficiently removing condensable particulate matter adopts the efficient condensable particulate matter removal system as described in any one of claims 1 to 9, specifically: sending the flue gas into a low-temperature condensation unit, using water vapor to condense with ultrafine particles as nuclei to form embryo droplets, thereby adsorbing the condensable particulate matter in the flue gas to be treated, and sending the condensed flue gas into a heat-carrying adsorption unit for heating, and then discharging it after adsorption by an adsorbent.

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