Catalytic adsorbent, preparation method thereof and coal-fired flue gas demercuration system

Abstract

The invention relates to the field of coal-fired flue gas demercuration, and provides a catalytic adsorbent, a preparation method thereof and a coal-fired flue gas demercuration system. The catalytic adsorbent comprises a metal oxide, a porous adsorption material, titanium dioxide and activated aluminum oxide; the metal oxides comprise copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide. The coal-fired flue gas demercuration system comprises an adsorbent injection device, a magnetic suction sorting device and a mercury analysis device. The adsorbent spraying device is used for spraying a catalytic adsorbent into the coal-fired flue gas based on a preset spraying point position, so that mercury in the coal-fired flue gas is adsorbed through the catalytic adsorbent. The magnetic attraction sorting device is used for adsorbing the catalytic adsorbent adsorbing mercury in the coal-fired flue gas and conveying the catalytic adsorbent to the mercury analysis device. And the mercury desorption device is used for desorbing the catalytic adsorbent adsorbed with mercury into elemental mercury and the desorbed catalytic adsorbent. The catalyst has high mercury adsorption capacity under different temperature and humidity conditions, and recycling of the catalytic adsorbent can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mercury removal from coal-fired flue gas, and in particular to a catalytic adsorbent and a preparation method thereof, and a coal-fired flue gas mercury removal system. Background Art

[0002] Mercury usually exists in three forms in coal-fired flue gas: elemental mercury Hg 0 , Oxidized mercury Hg 2+ and particulate mercury Hg p Among them, elemental mercury Hg 0 It is insoluble in water, highly volatile, difficult to capture and remove, but it can be partially oxidized to oxidized mercury Hg in a selective catalytic reduction (SCR) reactor. 2+ . Oxidized mercury Hg 2+ Easily absorbed by the slurry of the desulfurization system. Particle-state mercury Hg p Most of it is captured in the fly ash when passing through the dust collector. Therefore, it is necessary to remove the elemental mercury Hg in the coal-fired flue gas as much as possible. 0 , which can effectively reduce the concentration of mercury finally emitted from coal-fired flue gas.

[0003] At present, the existing technology mainly focuses on the removal of elemental mercury Hg in coal-fired flue gas. 0 Converted to oxidized mercury Hg 2+ Or particulate mercury Hg p. Among them, the activated carbon flue gas injection demercuration method is widely used. This demercuration method usually injects modified activated carbon as an adsorbent into the flue after the boiler air preheater to efficiently adsorb and remove flue gas mercury. The demercured adsorbent is effectively captured by a particulate matter control device such as a bag filter (Fabric Filter, FF) or an electrostatic precipitator (Electrostatic Precipitator, ESP) along with the fly ash. Studies have shown that the lower the adsorption temperature and the smaller the adsorbent particle size, the more conducive to the removal of mercury in coal-fired flue gas, but the outlet temperature of the boiler air preheater is usually high, which is not conducive to the removal of mercury in coal-fired flue gas. Some activated carbon flue gas injection demercuration methods will also inject adsorbents in the tail flue, such as after ESP and before FF. The temperature here is relatively low, but the flue gas flow rate is low, and the adsorbent is uneven after injection, affecting the demercuration effect. There is also an activated carbon flue gas injection mercury removal method that injects adsorbent at the wet electrostatic precipitator (WESP). The temperature at the WESP is the lowest, but the influence of moisture will also cause a certain degree of decrease in mercury removal efficiency. Studies have shown that when the amount of adsorbent is low, as the amount of adsorbent increases, its ability to adsorb mercury also increases accordingly. When the amount of adsorbent increases to a certain extent, its adsorption capacity becomes slow or even remains unchanged.

[0004] In addition, although activated carbon captures mercury and is removed along with fly ash by particulate matter capture equipment, some of the activated carbon that captures mercury still exists in the fly ash, and it must be evaluated when selling fly ash. In addition, fly ash is the main raw material for concrete, and if it is not demercured, it will cause secondary pollution of mercury. At the same time, if you want to reuse activated carbon, you also need to analyze the mercury in the activated carbon, but the cost is high.

[0005] Obviously, the existing activated carbon adsorbents not only have the problem of low mercury removal performance, but also have the problem of being unable to be recycled. Summary of the invention

[0006] The present disclosure aims to solve at least one of the problems existing in the prior art, and provides a catalytic adsorbent and a preparation method thereof, and a coal-fired flue gas mercury removal system.

[0007] In one aspect of the present disclosure, a catalytic adsorbent is provided, the catalytic adsorbent comprising a metal oxide, a porous adsorbent material, titanium dioxide and activated alumina;

[0008] The mass fraction of the metal oxide is 42.3% to 42.9%;

[0009] The mass fraction of the porous adsorption material is 30.8% to 35.7%;

[0010] The mass fraction of the titanium dioxide is 7.1% to 11.5%;

[0011] The mass fraction of the activated alumina is 14.3% to 15.4%;

[0012] The metal oxides include copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide;

[0013] Among them, the mass fraction of the copper oxide is 6.2% to 7.1%, the mass fraction of the manganese oxide is 4.3% to 4.6%, the mass fraction of the magnesium oxide is 7.7% to 8.6%, the mass fraction of the calcium oxide is 6.2% to 7.1%, the mass fraction of the iron oxide is 7.1% to 7.7%, and the mass fraction of the cerium oxide is 8.6% to 10%.

[0014] Optionally, the porous adsorption material includes activated carbon and zeolite; wherein the mass fraction of the activated carbon is 19.2% to 21.4%, and the mass fraction of the zeolite is 11.5% to 14.3%.

[0015] In one aspect of the present disclosure, a method for preparing a catalytic adsorbent is provided, which is used to prepare the catalytic adsorbent described above, and the preparation method comprises:

[0016] The copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide are uniformly mixed and then put into a grinding device for grinding to obtain a metal oxide mixture;

[0017] Mixing the porous adsorbent material with the metal oxide mixture, adding deionized water, and stirring at a first preset temperature for a first preset time to form a slurry; the first preset temperature ranges from 55° C. to 60° C.;

[0018] Adding titanium dioxide and activated alumina to the slurry, stirring at a preset speed for a second preset time to obtain a mixed agitation;

[0019] Placing the mixed mixture in an oven and drying it at a second preset temperature until the water is completely evaporated to obtain a dry mixture; the second preset temperature ranges from 80° C. to 90° C.;

[0020] The dry mixture is heated to a third preset temperature at a preset heating rate under a nitrogen atmosphere, and then naturally cooled to room temperature after being kept warm for a third preset time to obtain a catalytic adsorbent; the third preset temperature ranges from 280°C to 300°C.

[0021] Optionally, when the porous adsorption material comprises activated carbon and zeolite,

[0022] The mixing of the porous adsorbent material with the metal oxide mixture comprises: mixing the zeolite with the metal oxide mixture;

[0023] The adding titanium dioxide and activated alumina into the slurry comprises: adding pretreated activated carbon, the titanium dioxide and the activated alumina into the slurry.

[0024] Optionally, before adding the pretreated activated carbon, the titanium dioxide and the activated alumina to the slurry, the preparation method further comprises:

[0025] Pre-treating the activated carbon, placing the activated carbon in deionized water, stirring and soaking it, and then filtering it to obtain cleaned activated carbon;

[0026] Putting the cleaned activated carbon into an oven and maintaining it at a fourth preset temperature for a fourth preset time to obtain dried activated carbon; the fourth preset temperature ranges from 100° C. to 110° C.;

[0027] The dried activated carbon is heated to a fifth preset temperature in a nitrogen atmosphere and maintained for a fifth preset time to obtain the pretreated activated carbon; the fifth preset temperature ranges from 480°C to 500°C.

[0028] Another aspect of the present disclosure provides a coal-fired flue gas mercury removal system, the coal-fired flue gas mercury removal system comprising an adsorbent injection device, a magnetic separation device and a mercury analysis device; wherein:

[0029] The adsorbent injection device is used to inject the catalytic adsorbent described above or the catalytic adsorbent prepared by the preparation method described above into the coal-fired flue gas based on a preset injection point position, so as to adsorb mercury in the coal-fired flue gas through the catalytic adsorbent;

[0030] The magnetic separation device is used to absorb the catalytic adsorbent adsorbed with mercury in the coal-fired flue gas, and transport the catalytic adsorbent adsorbed with mercury to the mercury analysis device;

[0031] The mercury analysis device is used to analyze the catalytic adsorbent adsorbed with mercury into elemental mercury and the analyzed catalytic adsorbent.

[0032] Optionally, the mercury desorption device is further used to transport the desorbed catalytic adsorbent back to the adsorbent injection device.

[0033] Optionally, the mercury analysis device includes a drying box and a condensing device;

[0034] The drying box is used to volatilize the mercury and water in the catalytic adsorbent adsorbing mercury by heating to obtain the volatilized mercury and the desorbed catalytic adsorbent;

[0035] The condensing device is used to condense the volatilized mercury to obtain the elemental mercury.

[0036] Optionally, when the coal-fired flue gas passes through an electrostatic precipitator and a wet electrostatic precipitator in sequence, the preset injection point position includes an inlet position of the electrostatic precipitator and an inlet position of the wet electrostatic precipitator.

[0037] Optionally, the magnetic separation device is arranged at the fly ash outlet of the wet electrostatic precipitator.

[0038] Compared with the prior art, the present disclosure selects a variety of metal oxides and porous adsorption materials with different characteristics as components of the catalytic adsorbent. These metal oxides with different characteristics can play their respective catalytic and adsorption roles under different temperature and humidity conditions, so that the catalytic adsorbent can have a high catalytic adsorption capacity under different temperature and humidity conditions. In addition, the present disclosure also selects a magnetic substance as a component of the catalytic adsorbent, which enables the catalytic adsorbent to be magnetically separated, thereby realizing the recycling of the catalytic adsorbent. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0040] Figure 1 A flow chart of a method for preparing a catalytic adsorbent provided in one embodiment of the present disclosure;

[0041] Figure 2 A schematic diagram of the working principle of a coal-fired flue gas mercury removal system provided in another embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the embodiments of the present disclosure will be described in detail below in conjunction with the accompanying drawings. However, it can be understood by those skilled in the art that in each embodiment of the present disclosure, many technical details are proposed in order to enable readers to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical scheme claimed for protection in the present disclosure can also be implemented. The division of the following embodiments is for the convenience of description and should not constitute any limitation on the specific implementation of the present disclosure. The various embodiments can be combined and referenced with each other without contradiction.

[0043] One embodiment of the present disclosure relates to a catalytic adsorbent, which includes a metal oxide, a porous adsorbent material, titanium dioxide, and activated alumina. The mass fraction of the metal oxide is 42.3% to 42.9%. The mass fraction of the porous adsorbent material is 30.8% to 35.7%. The mass fraction of titanium dioxide is 7.1% to 11.5%. The mass fraction of activated alumina is 14.3% to 15.4%.

[0044] The metal oxides in the catalytic adsorbent include copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide. The mass fraction of copper oxide is 6.2% to 7.1%. The mass fraction of manganese oxide is 4.3% to 4.6%. The mass fraction of magnesium oxide is 7.7% to 8.6%. The mass fraction of calcium oxide is 6.2% to 7.1%. The mass fraction of iron oxide is 7.1% to 7.7%. The mass fraction of cerium oxide is 8.6% to 10%.

[0045] Specifically, copper oxide and iron oxide have certain catalytic activity at high temperatures, while cerium oxide can store and release oxygen at low temperatures and has better low-temperature activity. This enables the catalytic adsorbent provided in this embodiment to exert corresponding catalytic and adsorption effects through different components in the metal oxides under different temperature and humidity conditions. When it is used to remove mercury from coal-fired flue gas, it can have a high mercury adsorption capacity in both electrostatic precipitators and wet electrostatic precipitators.

[0046] In addition, iron oxide is also a magnetic substance, which enables the catalytic adsorbent provided in this embodiment to be magnetically separated. On this basis, the catalytic adsorbent after separation can be recycled and reapplied to related adsorption work such as mercury removal from coal flue gas, thereby realizing the recycling of the catalytic adsorbent.

[0047] The use of porous adsorption materials increases the specific surface area and pore structure of the catalytic adsorbent, which can effectively capture and adsorb pollutants at different temperatures and humidities.

[0048] Exemplarily, the porous adsorption material includes activated carbon and zeolite, wherein the mass fraction of the activated carbon is 19.2% to 21.4%, and the mass fraction of the zeolite is 11.5% to 14.3%.

[0049] Specifically, this embodiment uses activated carbon and zeolite as porous adsorption materials, which can enable the catalytic adsorbent to adapt to more temperature and humidity conditions, and can further improve the adsorption capacity of the catalytic adsorbent under different temperature and humidity conditions.

[0050] Compared with the prior art, the catalytic adsorbent provided in the embodiment of the present disclosure selects a variety of metal oxides and porous adsorption materials with different characteristics as the components of the catalytic adsorbent. These metal oxides with different characteristics can play their respective catalytic and adsorption effects under different temperature and humidity conditions, so that the catalytic adsorbent can have a high catalytic adsorption capacity under different temperature and humidity conditions. In addition, the catalytic adsorbent provided in the embodiment of the present disclosure also selects a magnetic substance, which enables the catalytic adsorbent to be magnetically separated, thereby realizing the recycling of the catalytic adsorbent.

[0051] Another embodiment of the present disclosure relates to a method for preparing a catalytic adsorbent, which is used to prepare the catalytic adsorbent described in the above embodiment. Figure 1 As shown, the method for preparing the catalytic adsorbent provided in this embodiment includes steps S110 to S150.

[0052] Step S110, copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide are mixed evenly and then put into a grinding device for grinding to obtain a metal oxide mixture.

[0053] Specifically, the present embodiment does not limit the specific type and model of the grinding equipment, and those skilled in the art can select it according to actual needs. For example, step S110 can use a ball mill to grind the mixed metal oxides at a speed of 300 rpm for 2 hours to obtain a metal oxide mixture.

[0054] Step S120, mixing the porous adsorption material with the metal oxide mixture, adding deionized water, stirring at a first preset temperature for a first preset time to form a slurry. The first preset temperature ranges from 55°C to 60°C.

[0055] Specifically, the first preset time can be set according to actual needs. For example, in step S120, the porous adsorption material, the metal oxide mixture and deionized water can be stirred at 55° C. to 60° C. for 1 hour to obtain a slurry.

[0056] Step S130, adding titanium dioxide and activated alumina to the slurry, stirring at a preset speed for a second preset time to obtain a mixed agitated product.

[0057] For example, in step S130 , the mixture of titanium dioxide, activated alumina and slurry may be stirred at a preset rotation speed of 200 rpm for 3 hours to obtain a mixed agitation.

[0058] Step S140, placing the mixed mixture in an oven and drying it at a second preset temperature until the water is completely evaporated to obtain a dry mixture. The second preset temperature ranges from 80°C to 90°C.

[0059] Specifically, step S140 is mainly to perform a drying process. For example, step S140 can use an oven at 80° C. to 90° C. to dry the mixed mixture for 4 hours until the water is completely evaporated to obtain a dry mixture.

[0060] Step S150, heating the dry mixture to a third preset temperature at a preset heating rate under a nitrogen atmosphere, keeping the temperature for a third preset time and then naturally cooling to room temperature to obtain a catalytic adsorbent. The third preset temperature ranges from 280°C to 300°C.

[0061] Specifically, step S150 can heat the dry mixture to 280° C. to 300° C. at a preset heating rate of 2° C. / min under a nitrogen atmosphere, keep the mixture warm for 3 hours, and then naturally cool the mixture to room temperature to obtain a catalytic adsorbent.

[0062] Exemplarily, when the porous adsorbent material includes activated carbon and zeolite, in step S120, the porous adsorbent material is mixed with the metal oxide mixture, including: mixing the zeolite with the metal oxide mixture. In step S130, titanium dioxide and activated alumina are added to the slurry, including: adding pretreated activated carbon, titanium dioxide and activated alumina to the slurry.

[0063] Specifically, since activated carbon and zeolite have different characteristics, activated carbon and zeolite can be added in different steps to improve the catalytic adsorption capacity of the finally obtained catalytic adsorbent.

[0064] Exemplarily, before adding the pretreated activated carbon, titanium dioxide and activated alumina to the slurry, the method for preparing the catalytic adsorbent further includes: pretreating the activated carbon, placing the activated carbon in deionized water, stirring and soaking it, and filtering it to obtain washed activated carbon. The washed activated carbon is placed in an oven and maintained at a fourth preset temperature for a fourth preset time to obtain dried activated carbon. The fourth preset temperature ranges from 100°C to 110°C. The dried activated carbon is heated to a fifth preset temperature under a nitrogen atmosphere and maintained for a fifth preset time to obtain pretreated activated carbon. The fifth preset temperature ranges from 480°C to 500°C.

[0065] Specifically, the pretreatment of activated carbon is mainly to remove surface impurities and dust on the activated carbon. For example, when pretreating activated carbon, the activated carbon can be first placed in a large amount of deionized water and stirred and soaked to remove surface impurities and dust on the activated carbon, and then filtered to obtain cleaned activated carbon. After that, the cleaned activated carbon is placed in an oven and dried at 100°C to 110°C for 3 hours to obtain dried activated carbon. Finally, the dried activated carbon is heated to 480°C to 500°C in a nitrogen atmosphere and maintained for 1 hour to obtain pretreated activated carbon.

[0066] It should be noted that the present embodiment does not limit the specific durations corresponding to the first preset duration, the second preset duration, the third preset duration, the fourth preset duration, and the fifth preset duration, respectively, and those skilled in the art may select and set them according to actual needs.

[0067] Compared with the prior art, the preparation method of the catalytic adsorbent provided in the embodiment of the present disclosure can enable the prepared catalytic adsorbent to play corresponding catalytic and adsorption effects under different temperature and humidity conditions through metal oxides and porous adsorption materials with different characteristics, thereby improving the catalytic adsorption capacity of the catalytic adsorbent under different temperature and humidity conditions. The catalytic adsorbent can also be recovered by magnetic separation to achieve the recycling of the catalytic adsorbent.

[0068] Another embodiment of the present disclosure relates to a coal-fired flue gas mercury removal system, which includes an adsorbent injection device, a magnetic separation device and a mercury analysis device.

[0069] The adsorbent injection device is used to inject the catalytic adsorbent described in the above embodiment or the catalytic adsorbent prepared by the preparation method of the catalytic adsorbent described in the above embodiment into the coal-fired flue gas based on a preset injection point position, so as to adsorb mercury in the coal-fired flue gas through the catalytic adsorbent.

[0070] Specifically, in the prior art, when coal-fired power plants use activated carbon flue gas injection to remove mercury from coal-fired flue gas, there are many optional adsorbent injection points, but each position has its corresponding disadvantages. Therefore, when the coal-fired flue gas passes through the electrostatic precipitator, the wet flue gas desulfurization device, and the wet electrostatic precipitator in sequence, Figure 2 In this embodiment, the preset injection point position is set to include the inlet position of the electrostatic precipitator and the inlet position of the wet electrostatic precipitator, so that the adsorbent injection device sprays an appropriate amount of catalytic adsorbent into the flue where the coal-fired flue gas is located at the inlet position of the electrostatic precipitator and the inlet position of the wet electrostatic precipitator. Since the adsorbent's adsorption capacity for mercury increases with the increase of its dosage when the dosage is low, and when the dosage of the adsorbent reaches a certain level, its adsorption capacity for mercury remains basically unchanged, therefore, by spraying an appropriate amount of catalytic adsorbent at the inlet position of the electrostatic precipitator and the inlet position of the wet electrostatic precipitator, not only the total amount of catalytic adsorbent can be reduced, but also the use efficiency of the catalytic adsorbent can be effectively improved.

[0071] The magnetic separation device is used for adsorbing the catalytic adsorbent adsorbed with mercury in the coal-fired flue gas, and transporting the catalytic adsorbent adsorbed with mercury to the mercury analysis device.

[0072] Specifically, the magnetic separation device is mainly used to recover the catalytic adsorbent adsorbed with mercury through magnetic separation.

[0073] For example, Figure 2 As shown, when the preset injection point position includes the inlet position of the electrostatic precipitator and the inlet position of the wet electrostatic precipitator, the magnetic separation device can be arranged at the fly ash outlet of the wet electrostatic precipitator.

[0074] Specifically, the catalytic adsorbent injected into the coal-fired flue gas by the adsorbent injection device will adsorb mercury in the coal-fired flue gas, and the catalytic adsorbent adsorbed with mercury will be captured by the wet electrostatic precipitator together with the fly ash, and then transported to the ash silo by the ash conveying system in the wet electrostatic precipitator. Therefore, the magnetic separation device can be arranged above the ash hopper for collecting fly ash in the ash silo to adsorb the catalytic adsorbent adsorbed with mercury mixed in the fly ash, thereby improving the recovery efficiency of the catalytic adsorbent. The coal-fired flue gas is demercured after passing through the wet electrostatic precipitator, and can then be discharged into the atmosphere through the chimney.

[0075] The mercury analysis device is used to analyze the catalytic adsorbent adsorbed with mercury into elemental mercury and the analyzed catalytic adsorbent.

[0076] Specifically, the mercury adsorbed in the catalytic adsorbent is usually particulate mercury, and the mercury analysis device mainly analyzes and separates the mercury adsorbed by the catalytic adsorbent from the catalytic adsorbent itself to obtain elemental mercury and the analyzed catalytic adsorbent. Among them, the elemental mercury can be sold separately, and the analyzed catalytic adsorbent can be reused for mercury removal from coal-fired flue gas, thereby realizing the recycling of the catalytic adsorbent.

[0077] Exemplarily, the mercury analysis device includes a drying box and a condensing device. The drying box is used to volatilize the mercury and water in the catalytic adsorbent adsorbed with mercury by heating to obtain the volatilized mercury and the analyzed catalytic adsorbent. The condensing device is used to condense the volatilized mercury to obtain elemental mercury.

[0078] Specifically, the drying box can play two roles: first, by heating, the mercury in the catalytic adsorbent adsorbed with mercury is volatilized, so that the volatilized mercury enters the condensation device for condensation, and the condensed mercury is elemental mercury; second, by heating, the water in the micropores of the catalytic adsorbent adsorbed with mercury is volatilized. After the water and mercury are volatilized, the analyzed catalytic adsorbent can be obtained, and the analyzed catalytic adsorbent can be reused for demercurization of coal-fired flue gas to achieve recycling.

[0079] Exemplarily, the mercury desorption device is further configured to transport the desorbed catalytic sorbent back to the sorbent injection device.

[0080] Specifically, since moisture is not conducive to the adsorption of mercury by the catalytic adsorbent, the catalytic adsorbent after analysis has completed the volatilization of moisture. Therefore, the catalytic adsorbent after analysis can be restored to its initial mercury adsorption capacity. The mercury analysis device can use the conveying device to convey the analyzed catalytic adsorbent back to the adsorbent injection device, thereby realizing the recycling of the catalytic adsorbent.

[0081] In order to enable those skilled in the art to better understand the coal-fired flue gas mercury removal system provided by the above embodiment, Figure 2 The working principle of the coal-fired flue gas mercury removal system is explained.

[0082] like Figure 2 As shown, the coal-fired flue gas passes through the electrostatic precipitator, the wet flue gas desulfurization device, the wet electrostatic precipitator and the chimney in sequence. Therefore, the preset injection point position is set at the entrance position of the electrostatic precipitator and the entrance position of the wet electrostatic precipitator, and the adsorbent injection device is used to inject an appropriate amount of the catalytic adsorbent described in the above embodiment or the catalytic adsorbent prepared by the preparation method of the catalytic adsorbent described in the above embodiment into the coal-fired flue gas at these two positions. The magnetic suction sorting device is set at the fly ash outlet of the wet electrostatic precipitator to adsorb the catalytic adsorbent adsorbed with mercury captured by the wet electrostatic precipitator along with the fly ash, and the adsorbed catalytic adsorbent adsorbed with mercury is transported to the mercury analysis device. The mercury analysis device analyzes the catalytic adsorbent adsorbed with mercury into elemental mercury and the analyzed catalytic adsorbent, and the analyzed catalytic adsorbent is transported back to the adsorbent injection device, thereby realizing the recycling of the catalytic adsorbent.

[0083] Compared with the prior art, the coal-fired flue gas mercury removal system provided in the embodiment of the present disclosure not only has a higher mercury adsorption capacity under different temperature and humidity conditions, but also can realize the recycling of catalytic adsorbents.

[0084] Those skilled in the art will appreciate that the above-mentioned embodiments are specific embodiments for implementing the present disclosure, and in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present disclosure.

Claims

1. A catalytic adsorbent, characterized in that: The catalytic adsorbent includes metal oxides, porous adsorbent materials, titanium dioxide and activated alumina; The mass fraction of the metal oxide is 42.3% to 42.9%; The mass fraction of the porous adsorption material is 30.8% to 35.7%; The mass fraction of the titanium dioxide is 7.1% to 11.5%; The mass fraction of the activated alumina is 14.3% to 15.4%; The metal oxides include copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide; Among them, the mass fraction of the copper oxide is 6.2% to 7.1%, the mass fraction of the manganese oxide is 4.3% to 4.6%, the mass fraction of the magnesium oxide is 7.7% to 8.6%, the mass fraction of the calcium oxide is 6.2% to 7.1%, the mass fraction of the iron oxide is 7.1% to 7.7%, and the mass fraction of the cerium oxide is 8.6% to 10%.

2. The catalytic adsorbent according to claim 1, characterized in that: The porous adsorption material comprises activated carbon and zeolite; wherein the mass fraction of the activated carbon is 19.2% to 21.4%, and the mass fraction of the zeolite is 11.5% to 14.3%.

3. A method for preparing a catalytic adsorbent, characterized in that: For preparing the catalytic adsorbent according to any one of claims 1 or 2, the preparation method comprises: The copper oxide, manganese oxide, magnesium oxide, calcium oxide, iron oxide and cerium oxide are uniformly mixed and then put into a grinding device for grinding to obtain a metal oxide mixture; Mixing the porous adsorbent material with the metal oxide mixture, adding deionized water, and stirring at a first preset temperature for a first preset time to form a slurry; the first preset temperature ranges from 55° C. to 60° C.; Adding titanium dioxide and activated alumina to the slurry, stirring at a preset speed for a second preset time to obtain a mixed agitation; Placing the mixed mixture in an oven and drying it at a second preset temperature until the water is completely evaporated to obtain a dry mixture; the second preset temperature ranges from 80° C. to 90° C.; The dry mixture is heated to a third preset temperature at a preset heating rate under a nitrogen atmosphere, and then naturally cooled to room temperature after being kept warm for a third preset time to obtain a catalytic adsorbent; the third preset temperature ranges from 280°C to 300°C.

4. The preparation method according to claim 3, characterized in that: When the porous adsorbent material includes activated carbon and zeolite, The mixing of the porous adsorbent material with the metal oxide mixture comprises: mixing the zeolite with the metal oxide mixture; The adding titanium dioxide and activated alumina into the slurry comprises: adding pretreated activated carbon, the titanium dioxide and the activated alumina into the slurry.

5. The preparation method according to claim 4, characterized in that: Before adding the pretreated activated carbon, the titanium dioxide and the activated alumina to the slurry, the preparation method further comprises: Pre-treating the activated carbon, placing the activated carbon in deionized water, stirring and soaking it, and then filtering it to obtain cleaned activated carbon; Putting the cleaned activated carbon into an oven and maintaining it at a fourth preset temperature for a fourth preset time to obtain dried activated carbon; the fourth preset temperature ranges from 100° C. to 110° C.; The dried activated carbon is heated to a fifth preset temperature in a nitrogen atmosphere and maintained for a fifth preset time to obtain the pretreated activated carbon; the fifth preset temperature ranges from 480°C to 500°C.

6. A coal-fired flue gas mercury removal system, characterized in that: The coal-fired flue gas mercury removal system comprises an adsorbent injection device, a magnetic separation device and a mercury analysis device; wherein, The adsorbent injection device is used to inject the catalytic adsorbent according to claim 1 or 2 or the catalytic adsorbent prepared by the preparation method according to any one of claims 3 to 5 into the coal-fired flue gas based on a preset injection point position, so as to adsorb mercury in the coal-fired flue gas through the catalytic adsorbent; The magnetic separation device is used to absorb the catalytic adsorbent adsorbed with mercury in the coal-fired flue gas, and transport the catalytic adsorbent adsorbed with mercury to the mercury analysis device; The mercury analysis device is used to analyze the catalytic adsorbent adsorbed with mercury into elemental mercury and the analyzed catalytic adsorbent.

7. The coal-fired flue gas mercury removal system according to claim 6, characterized in that: The mercury desorption device is also used to transport the desorbed catalytic adsorbent back to the adsorbent injection device.

8. The coal-fired flue gas mercury removal system according to claim 6, characterized in that: The mercury analysis device includes a drying box and a condensing device; The drying box is used to volatilize the mercury and water in the catalytic adsorbent adsorbing mercury by heating to obtain the volatilized mercury and the desorbed catalytic adsorbent; The condensing device is used to condense the volatilized mercury to obtain the elemental mercury.

9. The coal-fired flue gas mercury removal system according to any one of claims 6 to 8, characterized in that: When the coal-fired flue gas passes through the electrostatic precipitator and the wet electrostatic precipitator in sequence, the preset injection point position includes the inlet position of the electrostatic precipitator and the inlet position of the wet electrostatic precipitator.

10. The coal-fired flue gas mercury removal system according to claim 9, characterized in that: The magnetic separation device is arranged at the fly ash outlet of the wet electrostatic precipitator.

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