Catalytic flue gas desulfurization device and catalytic flue gas desulfurization method

Abstract

The invention relates to an improved catalytic flue gas desulfurization device and a catalytic flue gas desulfurization method, and aims to solve the technical problem that actual sulfur dioxide emission exceeds the standard due to fluctuation of the content of sulfur dioxide in desulfurized flue gas during operation of the catalytic flue gas desulfurization device. Comprising a first-stage catalytic flue gas desulfurization device used for receiving to-be-desulfurized flue gas, absorbing sulfur dioxide in the to-be-desulfurized flue gas through a catalyst, converting the sulfur dioxide into sulfuric acid existing on the catalyst, and outputting first-stage desulfurized flue gas; the second-stage catalytic flue gas desulfurization device is used for receiving the first-stage desulfurized flue gas, absorbing residual sulfur dioxide in the first-stage desulfurized flue gas through a catalyst, converting the residual sulfur dioxide into sulfuric acid existing on the catalyst, and outputting second-stage desulfurized flue gas; wherein the designed desulfurization amount of the first-stage catalytic flue gas desulfurization device is more than 90% of the overall desulfurization amount of the first-stage catalytic flue gas desulfurization device.

Description

Technical Field

[0001] The invention relates to the technical field of catalytic flue gas desulfurization, and in particular to a catalytic flue gas desulfurization device and a catalytic flue gas desulfurization method. Background Art

[0002] The basic principle of catalytic flue gas desulfurization technology is: sulfur dioxide, water, and oxygen in the flue gas to be desulfurized are adsorbed on the desulfurization catalyst (specifically, an activated carbon-based desulfurization catalyst) and react to generate sulfuric acid under the catalytic action of the active components; when the sulfuric acid attached to the desulfurization catalyst reaches a certain level, the desulfurization catalyst can be washed with a regeneration liquid (usually dilute sulfuric acid and / or water) to remove the attached sulfuric acid on the desulfurization catalyst and release the active sites of the desulfurization catalyst; the used regeneration liquid can be reused as a by-product (usually dilute sulfuric acid).

[0003] When catalytic flue gas desulfurization technology is applied to actual projects, it is usually necessary to build a special catalytic flue gas desulfurization tower, in which a desulfurization reactor is provided. The applicant has made a detailed introduction to the self-developed catalytic flue gas desulfurization equipment in patent documents such as publication numbers CN214764545U, CN114653202A, and CN114797450A. In general, the existing catalytic flue gas desulfurization equipment (such as a catalytic flue gas desulfurization tower) mainly includes a desulfurization reaction system, a regeneration liquid circulation system, and a flue gas conveying system. Of course, in order to achieve control over the operation process of the catalytic flue gas desulfurization equipment, the catalytic flue gas desulfurization equipment is usually also provided with a control system, which is connected to the instruments and meters in the catalytic flue gas desulfurization equipment.

[0004] Wherein, the desulfurization reaction system comprises a plurality of desulfurization reactors, each of which has an air inlet, an exhaust port, a liquid discharge port and the catalyst located in the desulfurization reactor, and the desulfurization reactor is provided with a regeneration liquid spraying device for washing and regenerating the catalyst. During operation, the flue gas to be desulfurized enters the desulfurization reactor from the air inlet of the desulfurization reactor, is desulfurized by the catalyst, and is then discharged from the exhaust port of the desulfurization reactor to become desulfurized flue gas. The sulfur dioxide in the flue gas to be desulfurized reacts on the catalyst when passing through the catalyst to form sulfuric acid. When the catalyst is washed and regenerated, the sulfuric acid enters the regeneration liquid sprayed on the catalyst and is then discharged from the liquid discharge port of the desulfurization reactor.

[0005] Wherein, the regeneration liquid circulation system comprises at least one regeneration liquid tank and a regeneration liquid circulation control pipeline network connected between the at least one regeneration liquid tank and each desulfurization reactor, the regeneration liquid circulation control pipeline network comprises an output side control pipeline network, an input side control pipeline network and a regeneration liquid driving device, the output side control pipeline network can introduce the regeneration liquid in the selected regeneration liquid tank into the regeneration liquid spraying device of the selected desulfurization reactor, the input side control pipeline network can introduce the regeneration liquid output from the discharge port of the selected desulfurization reactor into the selected regeneration liquid tank, and the regeneration liquid driving device can provide the required power to the regeneration liquid.

[0006] The flue gas delivery system includes an air intake network and an exhaust network, wherein the air intake network includes an air intake main pipe and air intake branches respectively connecting the air intake main pipe to the air intake ports of the desulfurization reactors, and the exhaust network includes an exhaust main pipe and exhaust branches respectively connecting the exhaust main pipe to the exhaust ports of the desulfurization reactors. Since the industrial-grade catalytic flue gas desulfurization equipment has a large flue gas treatment capacity, the diameter of each air intake branch pipe is also designed to be relatively large. In order to realize the on-off control of each air intake branch pipe, generally speaking, each air intake branch pipe has a curved portion extending downward, then turning back and extending upward. When it is necessary to cut off the air intake of the flue gas in the selected air intake branch pipe, a liquid sealing liquid is injected into the corresponding curved portion through a liquid inlet structure arranged on the corresponding curved portion to form a liquid seal for the curved portion. When it is necessary to conduct the air intake of the flue gas in the selected air intake branch pipe, the liquid sealing liquid in the corresponding curved portion is discharged through a liquid discharge structure arranged on the corresponding curved portion.

[0007] At present, during the implementation of the industrialization project of catalytic flue gas desulfurization equipment, the inventors have found that there is such a technical problem: when the sulfur dioxide content in the flue gas to be desulfurized is high (for example, the volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%), although the designed desulfurization efficiency of the catalytic flue gas desulfurization tower can theoretically enable the desulfurized flue gas to meet the sulfur dioxide emission requirements, but in the actual operation process, the sulfuric acid accumulated on the catalyst surface will gradually increase, resulting in the occupation of active sites, so that the catalytic desulfurization efficiency gradually decreases, and then causes the sulfur dioxide content in the desulfurized flue gas to show an increasing trend from low to high. This trend will change periodically with the switching of the desulfurization reactor in the catalyst washing and regeneration state. Such fluctuations in the sulfur dioxide content in the desulfurized flue gas may cause the actual sulfur dioxide emissions to exceed the standard. Summary of the invention

[0008] The purpose of the present invention is to provide an improved catalytic flue gas desulfurization device and a catalytic flue gas desulfurization method to solve the technical problem that the actual sulfur dioxide emission exceeds the standard due to the fluctuation of the sulfur dioxide content in the desulfurized flue gas during the operation of the catalytic flue gas desulfurization device.

[0009] In the first aspect, a catalytic flue gas desulfurization device is provided, characterized in that it comprises: a first-stage catalytic flue gas desulfurization device, wherein the first-stage catalytic flue gas desulfurization device is used to receive the flue gas to be desulfurized, and absorb the sulfur dioxide in the flue gas to be desulfurized through a catalyst and convert it into sulfuric acid present on the catalyst, and then output a first-stage desulfurized flue gas; a second-stage catalytic flue gas desulfurization device, wherein the second-stage catalytic flue gas desulfurization device is used to receive the first-stage desulfurized flue gas, and absorb the remaining sulfur dioxide in the first-stage desulfurized flue gas through a catalyst and convert it into sulfuric acid present on the catalyst, and then output a second-stage desulfurized flue gas; wherein the designed desulfurization amount of the first-stage catalytic flue gas desulfurization device is more than 90% of the overall desulfurization amount of the catalytic flue gas desulfurization device.

[0010] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: the volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%.

[0011] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: a catalytic flue gas desulfurization tower is used, and the catalytic flue gas desulfurization tower performs flue gas desulfurization through multiple desulfurization reactors; each desulfurization reactor has an air inlet, an exhaust port, a liquid discharge port and a catalyst located in the desulfurization reactor, and each desulfurization reactor is provided with a spray device for a regeneration liquid for washing and regenerating the catalyst. During desulfurization, the flue gas enters the desulfurization reactor from the air inlet and is discharged from the exhaust port after being desulfurized by the catalyst. The sulfur dioxide in the flue gas reacts on the catalyst to form sulfuric acid. When the catalyst is washed and regenerated, the sulfuric acid is passed through the exhaust port. The regeneration liquid oversprayed on the catalyst is recovered and discharged from the drain port; the multiple desulfurization reactors include a primary desulfurization reactor used as the primary catalytic flue gas desulfurization device and a secondary desulfurization reactor used as the secondary catalytic flue gas desulfurization device, the number of the primary desulfurization reactors is multiple, and the number of the secondary desulfurization reactors is at least two; the catalytic flue gas desulfurization tower includes a vertical column of desulfurization reactors, a first air intake network, a first exhaust network, a second air intake network, a second exhaust network and a regeneration liquid circulation system; the vertical column of desulfurization reactors includes a tower support structure, and the multiple desulfurization reactors are distributed in The tower support structure is provided on the tower support structure; the first air intake pipe network includes a first air intake main pipe and first air intake branches respectively connecting the first air intake main pipe to the air intake ports of the first-stage desulfurization reactors; the first exhaust pipe network includes a first exhaust main pipe and first exhaust branches respectively connecting the first exhaust main pipe to the air intake ports of the first-stage desulfurization reactors; the second air intake pipe network includes second air intake branches respectively connecting the first exhaust main pipe to the air intake ports of the second-stage desulfurization reactors; the second exhaust pipe network includes a second exhaust main pipe and first exhaust branches respectively connecting the second exhaust main pipe to the air intake ports of the second-stage desulfurization reactors. Each second exhaust branch pipe; a regeneration liquid circulation system, the regeneration liquid circulation system comprises at least one regeneration liquid tank and a regeneration liquid circulation control pipeline network connected between the at least one regeneration liquid tank and each desulfurization reactor, the regeneration liquid circulation control pipeline network comprises an output side control pipeline network, an input side control pipeline network and a regeneration liquid driving device, the output side control pipeline network can introduce the regeneration liquid in the selected regeneration liquid tank into the regeneration liquid spraying device of the selected desulfurization reactor, the input side control pipeline network can introduce the regeneration liquid output from the discharge port of the selected desulfurization reactor into the selected regeneration liquid tank, and the regeneration liquid driving device can provide the required power to the regeneration liquid.

[0012] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: the first pipeline on-off control mechanism corresponding to each first intake branch pipe and the second pipeline on-off control mechanism corresponding to each second intake branch pipe both adopt U-shaped liquid sealing devices.

[0013] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: during the normal operation of the catalytic flue gas desulfurization tower, there are always M primary desulfurization reactors operating in the desulfurization state and one primary desulfurization reactor operating in the catalyst washing and regeneration state, and at the same time, there are always N secondary desulfurization reactors operating in the desulfurization state and one secondary desulfurization reactor operating in the catalyst washing and regeneration state, wherein M>N, N is an integer ≥1; and when N≥2, the first-level desulfurized flue gas discharged from the M first-level desulfurization reactors operating in the desulfurization state is evenly distributed to the N secondary desulfurization reactors operating in the desulfurization state through the second air intake network.

[0014] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: the catalytic flue gas desulfurization tower has a total of six desulfurization reactors, four of the six desulfurization reactors are primary desulfurization reactors, and the other two desulfurization reactors are secondary desulfurization reactors; during the normal operation of the catalytic flue gas desulfurization tower, there are always three primary desulfurization reactors operating in the desulfurization state, and there is always one secondary desulfurization reactor operating in the desulfurization state.

[0015] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: the six desulfurization reactors are distributed in the upper and lower three floors of the tower support structure and two desulfurization reactors are arranged on the left and right sides of each floor of the tower support structure, the lower four desulfurization reactors of the catalytic flue gas desulfurization tower are respectively primary desulfurization reactors, and the upper two desulfurization reactors are respectively secondary desulfurization reactors.

[0016] As an optimization and / or instantiation of the above-mentioned catalytic flue gas desulfurization device, further: the catalyst is an activated carbon-based catalytic flue gas desulfurization catalyst.

[0017] In a second aspect, a catalytic flue gas desulfurization method is provided, comprising: inputting the flue gas to be desulfurized into a first-level catalytic flue gas desulfurization device for desulfurization, wherein the first-level catalytic flue gas desulfurization device absorbs sulfur dioxide in the flue gas to be desulfurized through a catalyst and converts it into sulfuric acid on the catalyst, and then outputs a first-level desulfurized flue gas; inputting the first-level desulfurized flue gas into a second-level catalytic flue gas desulfurization device for desulfurization, wherein the second-level catalytic flue gas desulfurization device absorbs the remaining sulfur dioxide in the first-level desulfurized flue gas through a catalyst and converts it into sulfuric acid on the catalyst, and then outputs a second-level desulfurized flue gas; wherein the designed desulfurization capacity of the first-level catalytic flue gas desulfurization device is more than 90% of the overall desulfurization capacity of the catalytic flue gas desulfurization device.

[0018] As an optimization and / or instantiation of the above catalytic flue gas desulfurization method, further: the volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%.

[0019] The above-mentioned catalytic flue gas desulfurization device and catalytic flue gas desulfurization method adopt the desulfurization concept of two-stage series catalytic flue gas desulfurization devices, in which the first-stage catalytic flue gas desulfurization device bears more than 90% of the desulfurization load, and the second-stage catalytic flue gas desulfurization device serves as a "safety guarantee" to specifically handle the small amount of sulfur dioxide escaping from the first-stage catalytic flue gas desulfurization device. The series desulfurization concept adopted by the above-mentioned catalytic flue gas desulfurization device and catalytic flue gas desulfurization method has a very small increase in cost (or even no increase in cost) compared to single-stage catalytic flue gas desulfurization, and can effectively solve the technical problem that the actual sulfur dioxide emission exceeds the standard due to the fluctuation of the sulfur dioxide content in the desulfurized flue gas when using single-stage catalytic flue gas desulfurization.

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. Additional aspects and advantages provided by the present invention will be partially given in the following description, partially become apparent from the following description, or be learned through practice. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of this specification are used to assist the understanding of the present invention. The contents provided in the drawings and the related descriptions in this specification can be used to explain the present invention, but do not constitute improper limitations on the present invention.

[0022] Figure 1 The present invention is a schematic structural diagram of a catalytic flue gas desulfurization device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The present invention is described clearly and completely below in conjunction with the accompanying drawings. A person skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0024] The technical solutions and technical features provided in each section, including the following description, can be combined with each other without conflict. In addition, where possible, these technical solutions, technical features and related combinations can be assigned specific technical themes and protected by relevant patents.

[0025] The embodiments of the present invention involved in the following description are generally only a part of the embodiments rather than all the embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of patent protection.

[0026] The terms "include", "comprises", "have" and any variations thereof in this specification and the corresponding claims and related parts are intended to cover non-exclusive inclusions. Other related terms and units can be reasonably interpreted based on the relevant content provided in this specification.

[0027] The catalytic flue gas desulfurization device of the embodiment of the present invention includes: a first-stage catalytic flue gas desulfurization device, the first-stage catalytic flue gas desulfurization device is used to receive the flue gas to be desulfurized, and absorb the sulfur dioxide in the flue gas to be desulfurized through a catalyst and convert it into sulfuric acid on the catalyst, and then output the first-stage desulfurized flue gas; a second-stage catalytic flue gas desulfurization device, the second-stage catalytic flue gas desulfurization device is used to receive the first-stage desulfurized flue gas, and absorb the remaining sulfur dioxide in the first-stage desulfurized flue gas through a catalyst and convert it into sulfuric acid on the catalyst, and then output the second-stage desulfurized flue gas. In addition, and most importantly, according to the design, the designed desulfurization amount of the first-stage catalytic flue gas desulfurization device is more than 90% of the overall desulfurization amount of the catalytic flue gas desulfurization device.

[0028] Specifically, if Figure 1As shown, the catalytic flue gas desulfurization device adopts a catalytic flue gas desulfurization tower, which performs flue gas desulfurization through multiple desulfurization reactors; each desulfurization reactor has an air inlet, an exhaust port, a liquid discharge port and a catalyst located in the desulfurization reactor, and each desulfurization reactor is provided with a spraying device for a regeneration liquid for washing and regenerating the catalyst. During desulfurization, the flue gas enters the desulfurization reactor from the air inlet and is desulfurized by the catalyst and then discharged from the exhaust port. The sulfur dioxide in the flue gas reacts on the catalyst to form sulfuric acid. When the catalyst is washed and regenerated, the sulfuric acid is recovered by the regeneration liquid sprayed on the catalyst and then discharged from the liquid discharge port; the multiple desulfurization reactors are provided with a spraying device for a regeneration liquid for washing and regenerating the catalyst. The sulfur reactor includes a primary desulfurization reactor 11 used as the primary catalytic flue gas desulfurization device and a secondary desulfurization reactor 12 used as the secondary catalytic flue gas desulfurization device. The number of the primary desulfurization reactors 11 is multiple, and the number of the secondary desulfurization reactors 12 is at least two; the catalytic flue gas desulfurization tower includes a desulfurization reactor vertical column, a first air intake network 21, a first exhaust network 31, a second air intake network 22, a second exhaust network 32 and a regeneration liquid circulation system 41; the desulfurization reactor vertical column includes a tower support structure, and the multiple desulfurization reactors are distributed on the tower support structure; the first air intake network 21 includes a first air intake network 21, a first exhaust network 31, a second air intake network 22, a second exhaust network 32 and a regeneration liquid circulation system 41. The first exhaust pipe network 31 includes a first exhaust main pipe 311 and first exhaust branch pipes 312 that connect the first exhaust main pipe 311 to the exhaust ports of the first desulfurization reactors 11; the second exhaust pipe network 22 includes second exhaust branch pipes 221 that connect the first exhaust main pipe 311 to the exhaust ports of the second desulfurization reactors 12; the second exhaust pipe network 32 includes a second exhaust main pipe 321 and second exhaust branch pipes 221 that connect the second exhaust main pipe 321 to the exhaust ports of the second desulfurization reactors 12. The second exhaust branch pipes 322 connected to the exhaust port of the desulfurization reactor 12; the regeneration liquid circulation system 41 includes at least one regeneration liquid tank 411 and a regeneration liquid circulation control pipe network connected between the at least one regeneration liquid tank 411 and each desulfurization reactor, the regeneration liquid circulation control pipe network has an output side control pipe network, an input side control pipe network and a regeneration liquid driving device, the output side control pipe network can introduce the regeneration liquid in the selected regeneration liquid tank into the regeneration liquid spraying device of the selected desulfurization reactor, the input side control pipe network can introduce the regeneration liquid output from the discharge port of the selected desulfurization reactor into the selected regeneration liquid tank, and the regeneration liquid driving device can provide the required power to the regeneration liquid. In addition, the first pipeline on-off control mechanism correspondingly arranged on each first air inlet branch pipe 212 and the second pipeline on-off control mechanism correspondingly arranged on each second air inlet branch pipe 221 both adopt U-shaped liquid sealing devices.

[0029] Regarding the specific working principles of the above-mentioned desulfurization reactors (primary desulfurization reactor 11 and secondary desulfurization reactor 12), regeneration liquid circulation system 41, and U-shaped liquid seal device, you can directly refer to the relevant content provided by the applicant in patent documents with publication numbers CN214764545U, CN114653202A, CN114797450A, etc. If the contents of these patent documents are regarded as prior art, then the main difference of the catalytic flue gas desulfurization device of the embodiment of the present invention is that the original multiple desulfurization reactors are divided into a first-level desulfurization reactor 11 used as the first-level catalytic flue gas desulfurization device and a second-level desulfurization reactor 12 used as the second-level catalytic flue gas desulfurization device, and the structures of the intake pipe network and the exhaust pipe network are adjusted accordingly (the most important thing is to connect the first exhaust main pipe 311 to the air inlet of each second-level desulfurization reactor 12 through each second intake branch pipe 221), so that the flue gas to be desulfurized can be first input into the first-level catalytic flue gas desulfurization device for desulfurization and then output the first-level desulfurized flue gas, and then the first-level desulfurized flue gas is input into the second-level catalytic flue gas desulfurization device for desulfurization and then output the second-level desulfurized flue gas.

[0030] During the normal operation of the above-mentioned catalytic flue gas desulfurization tower, it is ensured that there are always M primary desulfurization reactors 11 operating in the desulfurization state and one primary desulfurization reactor 11 operating in the catalyst washing and regeneration state, and at the same time, there are always N secondary desulfurization reactors 12 operating in the desulfurization state and one secondary desulfurization reactor 12 operating in the catalyst washing and regeneration state, wherein M>N, N is an integer ≥1; and when N≥2, the primary desulfurized flue gas discharged from the M primary desulfurization reactors operating in the desulfurization state is evenly distributed to the N secondary desulfurization reactors operating in the desulfurization state through the second air intake network. In this way, it can be ensured that the regeneration cycles of the primary desulfurization reactor 11 and the secondary desulfurization reactor 12 are staggered, and even if the overall desulfurization efficiency of the primary desulfurization reactor 11 fluctuates slightly, the fluctuation of the overall desulfurization efficiency of the secondary desulfurization reactor 12 can be staggered with the trough of the overall desulfurization efficiency of the primary desulfurization reactor 11.

[0031] Specifically, in this embodiment, the catalytic flue gas desulfurization tower has a total of six desulfurization reactors, four of the six desulfurization reactors are respectively primary desulfurization reactors 11, and the other two desulfurization reactors are respectively secondary desulfurization reactors 12; during the normal operation of the catalytic flue gas desulfurization tower, there are always three primary desulfurization reactors 11 operating in the desulfurization state ("3+1" mode, i.e., 3 operating in the desulfurization state, and 1 operating in the catalyst washing and regeneration state), and there is always one secondary desulfurization reactor 12 operating in the desulfurization state ("1+1" mode, i.e., 1 operating in the desulfurization state, and 1 operating in the catalyst washing and regeneration state).

[0032] It can be seen that the catalytic flue gas desulfurization device of the embodiment of the present invention can be based on the original catalytic flue gas desulfurization tower of six desulfurization reactors, by dividing the first-level desulfurization reactor 11 and the second-level desulfurization reactor 12 and simply adjusting the structure of the intake pipe network and the exhaust pipe network, and then changing the working mode of the original catalytic flue gas desulfurization tower of six desulfurization reactors, so as to obtain the catalytic flue gas desulfurization device of the embodiment of the present invention. The cost of this transformation is very low, and it hardly increases the operating cost, but it can solve the problem well. When the sulfur dioxide content in the flue gas to be desulfurized is high (for example, the volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%), although the designed desulfurization efficiency of the catalytic flue gas desulfurization tower can theoretically make the desulfurized flue gas meet the sulfur dioxide emission requirements, but in the actual operation process, the sulfuric acid accumulated on the catalyst surface will gradually increase, resulting in the occupation of active sites, so that the catalytic desulfurization efficiency gradually decreases, and then the sulfur dioxide content in the desulfurized flue gas shows an increasing trend from low to high. This trend will change periodically with the switching of the desulfurization reactor in the catalyst washing and regeneration state. The fluctuation of the sulfur dioxide content in the desulfurized flue gas may lead to the problem of actual sulfur dioxide emissions exceeding the standard.

[0033] The above-mentioned catalytic flue gas desulfurization device adopts the desulfurization concept of two-stage series catalytic flue gas desulfurization devices, in which the first-stage catalytic flue gas desulfurization device bears more than 90% of the desulfurization load, and the second-stage catalytic flue gas desulfurization device serves as a "safety guarantee" to specifically handle the small amount of sulfur dioxide escaping from the first-stage catalytic flue gas desulfurization device. The series desulfurization concept adopted by the above-mentioned catalytic flue gas desulfurization device and catalytic flue gas desulfurization method has a very small increase in cost (or even no increase in cost) compared to single-stage catalytic flue gas desulfurization, and can effectively solve the technical problem that the actual sulfur dioxide emission exceeds the standard due to the fluctuation of the sulfur dioxide content in the desulfurized flue gas when using single-stage catalytic flue gas desulfurization.

[0034] In addition, although the catalytic flue gas desulfurization device of the embodiment of the present invention is provided with a first-stage catalytic flue gas desulfurization device and a second-stage catalytic flue gas desulfurization device, the amount of catalyst used may not increase or only increase slightly, thereby reducing the operating cost of the catalytic flue gas desulfurization device.

[0035] For example, if a catalytic flue gas desulfurization tower originally used four desulfurization reactors, and the embodiment of the present invention is adjusted to a catalytic flue gas desulfurization tower with six desulfurization reactors, the total amount of catalyst used in the six desulfurization reactors can be substantially the same as the total amount of catalyst used in the catalytic flue gas desulfurization tower originally using four desulfurization reactors. Specifically, the flue gas treatment capacity to be desulfurized is 2400000Nm 3 / h, the catalytic flue gas desulfurization tower originally used four desulfurization reactors, according to the "3+1" mode (that is, 3 are running in the desulfurization state, and 1 is running in the catalyst washing and regeneration state), the catalyst consumption of each desulfurization reactor is 230m 3 (Catalyst bed thickness is 2.8m-3.2m), total catalyst volume: 228.57m 3 ×4=914.28m 3 After the embodiment of the present invention is adjusted to a catalytic flue gas desulfurization tower with six desulfurization reactors, four desulfurization reactors are respectively the primary desulfurization reactor 11, and the other two desulfurization reactors are respectively the secondary desulfurization reactor 12. At this time, the amount of catalyst used in each primary desulfurization reactor 11 can be reduced to 180m 3 (The catalyst bed thickness can usually be set to 2m-2.5m), and the catalyst dosage of each secondary desulfurization reactor 12 can be set to 100m 3 (The thickness of the catalyst bed can usually be set to 1m-1.5m). Thus, the total amount of catalyst used in the catalytic flue gas desulfurization tower adjusted to six desulfurization reactors in the embodiment of the present invention is the same as that used in the catalytic flue gas desulfurization tower originally using four desulfurization reactors.

[0036] In this embodiment, the content of sulfur dioxide in the flue gas to be desulfurized is as high as 34000 mg / Nm 3 The sulfur dioxide content in the first-stage desulfurized flue gas is reduced to 2000 mg / Nm 3 The sulfur dioxide content in the secondary desulfurized flue gas can be stabilized at 30 mg / Nm 3 the following.

[0037] The above is a description of the relevant contents of the present invention. A person skilled in the art will be able to implement the present invention based on these descriptions. Based on the above contents of this specification, all other embodiments obtained by a person skilled in the art without making creative work should fall within the scope of the present invention.

Claims

1. Catalytic flue gas desulfurization device, characterized in that: include: A primary catalytic flue gas desulfurization device, which is used to receive the flue gas to be desulfurized, absorb the sulfur dioxide in the flue gas to be desulfurized through a catalyst and convert it into sulfuric acid on the catalyst, and then output the primary desulfurized flue gas; A secondary catalytic flue gas desulfurization device, which is used to receive the primary desulfurized flue gas, absorb the remaining sulfur dioxide in the primary desulfurized flue gas through a catalyst and convert it into sulfuric acid on the catalyst, and then output the secondary desulfurized flue gas; Wherein, the designed desulfurization capacity of the first-stage catalytic flue gas desulfurization device is more than 90% of the overall desulfurization capacity of the catalytic flue gas desulfurization device.

2. The catalytic flue gas desulfurization device according to claim 1, characterized in that: The volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%.

3. The catalytic flue gas desulfurization device according to claim 1, characterized in that: A catalytic flue gas desulfurization tower is used, which desulfurizes flue gas through multiple desulfurization reactors; Each desulfurization reactor has an air inlet, an exhaust port, a liquid discharge port, and a catalyst located in the desulfurization reactor. Each desulfurization reactor is provided with a spraying device for a regeneration liquid for washing and regenerating the catalyst. During desulfurization, flue gas enters the desulfurization reactor from the air inlet and is discharged from the exhaust port after being desulfurized by the catalyst. The sulfur dioxide in the flue gas reacts on the catalyst to form sulfuric acid. When the catalyst is washed and regenerated, the sulfuric acid is recovered by the regeneration liquid sprayed on the catalyst and then discharged from the liquid discharge port. The multiple desulfurization reactors include a primary desulfurization reactor used as the primary catalytic flue gas desulfurization device and a secondary desulfurization reactor used as the secondary catalytic flue gas desulfurization device, the number of the primary desulfurization reactors is multiple, and the number of the secondary desulfurization reactors is at least two; The catalytic flue gas desulfurization tower comprises a vertical row of desulfurization reactors, a first air intake pipe network, a first exhaust pipe network, a second air intake pipe network, a second exhaust pipe network and a regeneration liquid circulation system; The vertical row of desulfurization reactors comprises a tower support structure, and the plurality of desulfurization reactors are distributed on the tower support structure; The first air intake pipe network comprises a first air intake main pipe and first air intake branch pipes respectively connecting the first air intake main pipe to the air intake ports of the first-stage desulfurization reactors; The first exhaust pipe network comprises a first exhaust main pipe and first exhaust branch pipes respectively connecting the first exhaust main pipe to the exhaust ports of the first-level desulfurization reactors; The second air intake pipe network comprises second air intake branches which respectively connect the first exhaust manifold to the air intakes of the secondary desulfurization reactors; The second exhaust pipe network comprises a second exhaust main pipe and second exhaust branch pipes respectively connecting the second exhaust main pipe to the exhaust ports of the secondary desulfurization reactors; The regeneration liquid circulation system comprises at least one regeneration liquid tank and a regeneration liquid circulation control pipeline network connected between the at least one regeneration liquid tank and each desulfurization reactor, the regeneration liquid circulation control pipeline network comprises an output side control pipeline network, an input side control pipeline network and a regeneration liquid driving device, the output side control pipeline network can introduce the regeneration liquid in the selected regeneration liquid tank into the regeneration liquid spraying device of the selected desulfurization reactor, the input side control pipeline network can introduce the regeneration liquid output from the discharge port of the selected desulfurization reactor into the selected regeneration liquid tank, and the regeneration liquid driving device can provide the required power to the regeneration liquid.

4. The catalytic flue gas desulfurization device according to claim 3, characterized in that: The first pipeline on-off control mechanism correspondingly arranged on each first air intake branch pipe and the second pipeline on-off control mechanism correspondingly arranged on each second air intake branch pipe both adopt a U-shaped liquid sealing device.

5. The catalytic flue gas desulfurization device according to claim 3, characterized in that: During the normal operation of the catalytic flue gas desulfurization tower, there are always M primary desulfurization reactors operating in the desulfurization state and one primary desulfurization reactor operating in the catalyst washing and regeneration state. At the same time, there are always N secondary desulfurization reactors operating in the desulfurization state and one secondary desulfurization reactor operating in the catalyst washing and regeneration state, wherein M>N, N is an integer ≥1; and when N≥2, the first-stage desulfurized flue gas discharged from the M first-stage desulfurization reactors operating in the desulfurization state is evenly distributed to the N secondary desulfurization reactors operating in the desulfurization state through the second air inlet network.

6. The catalytic flue gas desulfurization device according to claim 5, characterized in that: The catalytic flue gas desulfurization tower has a total of six desulfurization reactors, four of which are primary desulfurization reactors, and the other two are secondary desulfurization reactors; during the normal operation of the catalytic flue gas desulfurization tower, there are always three primary desulfurization reactors operating in the desulfurization state, and there is always one secondary desulfurization reactor operating in the desulfurization state.

7. The catalytic flue gas desulfurization device according to claim 6, characterized in that: The six desulfurization reactors are distributed in the upper and lower three floors of the tower support structure, and two desulfurization reactors are arranged on the left and right sides of each floor of the tower support structure. The lower four desulfurization reactors of the catalytic flue gas desulfurization tower are respectively primary desulfurization reactors, and the upper two desulfurization reactors are respectively secondary desulfurization reactors.

8. The catalytic flue gas desulfurization device according to claim 1, characterized in that: The catalyst is an activated carbon-based catalytic flue gas desulfurization catalyst.

9. A catalytic flue gas desulfurization method, characterized in that: include: The flue gas to be desulfurized is input into a primary catalytic flue gas desulfurization device for desulfurization, wherein the primary catalytic flue gas desulfurization device absorbs sulfur dioxide in the flue gas to be desulfurized through a catalyst and converts it into sulfuric acid present on the catalyst, and then outputs a primary desulfurized flue gas; The primary desulfurized flue gas is input into a secondary catalytic flue gas desulfurization device for desulfurization, wherein the secondary catalytic flue gas desulfurization device absorbs the remaining sulfur dioxide in the primary desulfurized flue gas through a catalyst and converts it into sulfuric acid present on the catalyst, and then outputs the secondary desulfurized flue gas; Wherein, the designed desulfurization capacity of the first-stage catalytic flue gas desulfurization device is more than 90% of the overall desulfurization capacity of the catalytic flue gas desulfurization device.

10. The catalytic flue gas desulfurization method according to claim 1, characterized in that: The volume fraction of sulfur dioxide in the flue gas to be desulfurized is 0.1%-3%.

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