Calculation method of active substance loading capacity in denitration catalyst regeneration and demercuration process

Abstract

The invention provides a method for calculating the active substance loading capacity in the regeneration and demercuration process of a denitration catalyst, which comprises the following steps of: determining the mercury oxidation efficiency of the catalyst and influence factors of denitration activity through a simulation test, and obtaining a fitting formula of a denitration active component V2O5 and a demercuration active component X; determining boundary conditions before catalyst regeneration: determining flue gas conditions of catalyst operation through field testing; according to a catalyst mercury oxidation efficiency target value and a denitration activity target value, in combination with the boundary conditions and the fitting formula, obtaining value ranges of a denitration active component V2O5 and a demercuration active component X; the minimum value of the denitration active component V2O5 and the minimum value of the demercuration active component X are taken as the optimal concentration ratio of the catalyst, and the active substance loading capacity is obtained by combining the initial conditions before regeneration of the catalyst. One technical effect of the invention is that the catalyst is helpful to have good denitration capability and demercuration capability at the same time.

Description

Technical Field

[0001] The present invention belongs to the technical field of flue gas denitrification, and particularly relates to a calculation method for the loading amount of active substances during the regeneration and mercury removal of denitrification catalysts. Background Art

[0002] SCR commercial denitrification catalysts have a certain mercury removal performance, but the performance is not high. Therefore, during the catalyst regeneration process, active components with strong mercury removal ability can be appropriately supplemented to improve their mercury removal performance. However, catalyst regeneration is usually carried out during the unit overhaul period, and the construction period is generally about one month. Considering the entire process of unit cooling, catalyst removal, transportation, regeneration, transportation back to the power plant, installation, etc., the catalyst regeneration construction period is very tight. At the same time, the catalyst components and performance of different plants are different, and the reaction conditions are different, so the amount of active components to be loaded is also different. How to determine the loading amount of active components within the limited overhaul period to achieve the purpose of mercury removal while ensuring the denitrification ability has become an urgent technical problem to be solved. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art, and provides a new technical solution for a calculation method for the loading amount of active substances during the regeneration and mercury removal of denitrification catalysts.

[0004] According to the first aspect of the present invention, there is provided a calculation method for the loading amount of active substances during the regeneration and mercury removal of denitrification catalysts, including the following steps:

[0005] Step S1, determining the mercury oxidation efficiency of the catalyst and the influencing factors of denitrification activity through simulation tests, and obtaining the fitting formulas of the denitrification active component V 2 O 5 and the mercury removal active component X; wherein, the influencing factors include flue gas conditions and catalyst composition;

[0006] Step S2, determining the boundary conditions before catalyst regeneration: determining the flue gas conditions under which the catalyst operates through on-site testing, and determining the initial conditions before regeneration of the catalyst through sampling and analysis; wherein, the initial conditions before regeneration of the catalyst include the denitrification activity of the catalyst and the TiO 2 / V 2 O 5 / X content;

[0007] Step S3, according to the target value of the mercury oxidation efficiency of the catalyst and the target value of denitrification activity, combining the boundary conditions with the fitting formulas, obtaining the value ranges of the denitrification active component V 2 O 5 and the mercury removal active component X;

[0008] Step S4, taking the denitrification active component V2 O 5 The minimum value of and the minimum value of the mercury removal active component X are used as the optimal concentration ratio of the catalyst, and the active substance loading amount is obtained in combination with the initial conditions before the regeneration of the catalyst.

[0009] Optionally, in step S2, the sampling analysis includes activity detection and XRD detection. The activity detection is used to obtain the denitrification activity of the catalyst, and the XRD detection is used to obtain the TiO 2 / V 2 O 5 / X content.

[0010] Optionally, in step S1, the simulation test includes the following steps:

[0011] First, a variety of catalyst samples are prepared by the impregnation method; among them, the components of the catalyst samples include a denitrification active component and a mercury removal active component, and the ratios of the denitrification active component and the mercury removal active component in different catalyst samples are different;

[0012] Then, the various catalyst samples are successively placed in a simulation reactor for a simulation test. Different simulated flue gases are introduced into the simulation reactor from the inlet of the simulation reactor, and the simulated flue gases are subjected to mercury removal and denitrification by the catalyst samples; among them, mercury concentration analyzers and flue gas concentration analyzers are provided at both the inlet and the outlet of the simulation reactor. The mercury concentration analyzer is used to measure the mercury concentration, and the flue gas concentration analyzer is used to measure the NO concentration; the flue gas component conditions of different simulated flue gases are different;

[0013] Finally, the mercury oxidation efficiency is calculated according to the measured values of the mercury concentration analyzers at the inlet and the outlet of the simulation reactor, and the denitrification efficiency is calculated according to the measured values of the flue gas concentration analyzers at the inlet and the outlet of the simulation reactor.

[0014] Optionally, the calculation formula for the mercury oxidation efficiency of the simulation test is as follows:

[0015]

[0016] In the above formula: is the elemental mercury concentration at the reactor inlet, with the unit of μg / m 3 ; is the elemental mercury concentration at the outlet of the simulation reactor, with the unit of μg / m 3 ; η Hg is the mercury oxidation efficiency, with the unit of %.

[0017] Optionally, the calculation formula for the denitrification activity K is as follows:

[0018] K = -Av × ln(1 - η NO )

[0019] In the above formula, Av is the face velocity, which is a set value; η NO is the denitrification efficiency.

[0020] Optionally, in step S1, the fitting formula of the denitrification active component V 2 O 5 is as follows:

[0021] η Hg = f(NH 3 , SO 2 , HCl, V 2 O 5 );

[0022] The fitting formula of the mercury removal active component X is as follows:

[0023] K = f(V 2 O 5 , X, S);

[0024] In the above formula, S is the specific surface area.

[0025] Optionally, the denitrification activity satisfies the following formula:

[0026] f(V 2 O 5 , X, S 设计 ) > K 1 ;

[0027] In the above formula, K 1 is the target activity, and S 设计 is the design value of the specific surface area of the catalyst.

[0028] Optionally, the calculation formula of the mercury oxidation efficiency of a coal-fired power plant is as follows:

[0029]

[0030] In the above, is the elemental mercury concentration at the reactor inlet, with the unit of μg / m 3 ; is the mercury emission concentration required by the standard, with the unit of μg / m 3 ; η Hg，目标 is the target mercury oxidation efficiency, with the unit of %.

[0031] Optionally, the mercury oxidation efficiency of a coal-fired power plant needs to satisfy:

[0032] f(NH 3 , SO 2 , HCl, V 2 O 5 , X) > η Hg，目标 .

[0033] Optionally, the simulated flue gas includes NO, NH 3 , SO 2 , HCl, O 2 and mercury vapor.

[0034] Optionally, in the simulated flue gas, O 2 is sourced from cylinder gas and mercury vapor is sourced from a mercury generator.

[0035] One technical effect of the present invention is that:

[0036] In the embodiments of the present application, the calculation method for the loading amount of active substances during the denitrification catalyst regeneration and mercury removal process is reasonably designed, and can reasonably distribute the concentrations of V 2 O 5 and X during the regeneration process, so that the catalyst has both good denitrification ability and mercury removal ability, and will not cause excessive and wasteful active components. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic flow chart of a calculation method for the loading amount of active substances during the denitrification catalyst regeneration and mercury removal process according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0039] Embodiments of the present application will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary only for explaining the present application and should not be construed as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts fall within the scope of protection of the present application.

[0040] The terms "first" and "second" in the description and claims of the present application may explicitly or implicitly include one or more of such features. In the description of the present application, unless otherwise specified, "a plurality of" means two or more. In addition, "and / or" in the description and claims means at least one of the connected objects, and the character " / " generally indicates an "or" relationship between the associated objects before and after.

[0041] According to a first aspect of the present invention, refer to Figure 1, a calculation method for the loading amount of active substances during the regeneration and mercury removal of denitration catalysts is provided, including the following steps:

[0042] Step S1, determine the mercury oxidation efficiency of the catalyst and the influencing factors of denitration activity through simulation tests, and obtain the fitting formulas of the denitration active component V 2 O 5 and the mercury removal active component X; wherein, the influencing factors include flue gas conditions and catalyst composition;

[0043] Step S2, determine the boundary conditions before catalyst regeneration: during the operation of the unit, determine the flue gas conditions under which the catalyst operates through on-site testing; after the unit shuts down and cools, determine the initial conditions before regeneration of the catalyst through sampling and analysis; wherein, the initial conditions before regeneration of the catalyst include the denitration activity K 0 of the catalyst and the TiO 2 / V 2 O 5 / X content;

[0044] Step S3, according to the target value of the mercury oxidation efficiency of the catalyst and the target value of denitration activity, combined with the boundary conditions and the fitting formulas, obtain the value ranges of the denitration active component V 2 O 5 and the mercury removal active component X;

[0045] Step S4, take the minimum value of the denitration active component V 2 O 5 and the minimum value of the mercury removal active component X as the best concentration ratio of the catalyst, and obtain the loading amount of active substances in combination with the initial conditions before regeneration of the catalyst.

[0046] It should be noted that the denitration active component of commercial SCR catalysts is V 2 O 5 , and the mercury removal active component is set as X in the present invention. Research shows that V 2 O 5 has strong denitration performance and has a certain effect on mercury oxidation, but its mercury oxidation ability is weak, while the mercury removal active component X has strong denitration performance and has a certain effect on denitration performance, but its denitration performance is weak.

[0047] In the embodiments of the present application, the calculation method for the loading amount of active substances during the regeneration and mercury removal of the denitration catalyst is reasonably designed, and can reasonably distribute the concentrations of V 2 O 5 and X during the regeneration process, so that the catalyst has good denitration ability and mercury removal ability at the same time, and will not cause excessive and waste of active components.

[0048] Specifically, the calculation method of the active substance loading during the denitrification catalyst regeneration and mercury removal process in the embodiments of the present application determines the influencing factors of the catalyst mercury oxidation efficiency and denitrification activity through simulation tests, mainly including flue gas conditions and catalyst components, etc., and obtains relevant fitting formulas. On this basis, the boundary conditions before catalyst regeneration are determined, the flue gas conditions during the operation of the catalyst are determined through on-site testing, and the initial conditions before catalyst regeneration are determined through sampling and analysis. Before regeneration, through the target values of the catalyst mercury oxidation efficiency and denitrification activity, combined with the boundary conditions and the fitting formula, the value range of the denitrification active component V 2 O 5 and the mercury removal active component X is obtained, and the minimum value is taken as the optimal concentration ratio, and the active substance loading is obtained in combination with the initial conditions.

[0049] Optionally, in step S2, the sampling and analysis includes activity detection and XRD detection. The activity detection is used to obtain the denitrification activity of the catalyst, and the XRD detection is used to obtain the TiO 2 / V 2 O 5 / X content. This helps to accurately and quickly perform activity detection and XRD detection.

[0050] Optionally, in step S1, the simulation test includes the following steps:

[0051] First, a variety of catalyst samples are prepared by the impregnation method; wherein, the components of the catalyst samples include denitrification active components and mercury removal active components, and the ratios of the denitrification active components and mercury removal active components of different catalyst samples are different;

[0052] Then, various catalyst samples are successively placed in a simulation reactor for simulation tests. Different simulated flue gases are introduced into the simulation reactor from the inlet of the simulation reactor, and the simulated flue gases are subjected to mercury removal and denitrification by the catalyst samples; wherein, mercury concentration analyzers and flue gas concentration analyzers are provided at both the inlet and the outlet of the simulation reactor. The mercury concentration analyzer is used to measure the mercury concentration, and the flue gas concentration analyzer is used to measure the NO concentration; the flue gas component conditions of different simulated flue gases are different;

[0053] Finally, the mercury oxidation efficiency is calculated according to the measured values of the mercury concentration analyzers at the inlet and the outlet of the simulation reactor, and the denitrification efficiency is calculated according to the measured values of the flue gas concentration analyzers at the inlet and the outlet of the simulation reactor.

[0054] In the above embodiment, there are many influencing factors for the mercury oxidation efficiency. According to the literature, they usually include flue gas components and catalyst components. The present invention first conducts basic experiments on the influencing factors of the catalyst mercury oxidation efficiency in the laboratory.

[0055] It should be noted that during the test, the flue gas component conditions (NO, NH 3 , SO 2 , HCl, O2) were changed, and the mercury concentration and NO concentration were simultaneously measured at the inlet and outlet of the simulated reactor to obtain the mercury oxidation efficiency and denitrification efficiency.

[0056] Optionally, the calculation formula for the mercury oxidation efficiency of the simulated test is as follows:

[0057]

[0058] In the above formula: is the elemental mercury concentration at the reactor inlet, with the unit of μg / m 3 ; is the elemental mercury concentration at the outlet of the simulated reactor, with the unit of μg / m 3 ; η Hg is the mercury oxidation efficiency, with the unit of %.

[0059] Optionally, the calculation method of the denitrification efficiency η NO is the same as the calculation formula for the mercury oxidation efficiency of the simulated test, and the denitrification activity K is further calculated. The calculation formula for the denitrification activity K is as follows:

[0060] K = -Av × ln(1 - η NO );

[0061] In the above formula, Av is the superficial velocity, which is a set value; η NO is the denitrification efficiency. This helps to accurately and quickly calculate the denitrification activity K.

[0062] It should be noted that during the test, the flue gas component conditions were simultaneously recorded, and combined with the composition of the catalyst sample used in the test, the fitting formulas for the mercury oxidation efficiency and denitrification activity can be obtained through a large number of tests.

[0063] Furthermore, the activity of the catalyst is its performance, which is independent of the reaction conditions and mainly related to the composition and the specific surface area S at the microscale.

[0064] Optionally, in step S1, the fitting formula for the denitrification active component V 2 O 5 is as follows:

[0065] η Hg = f(NH 3 , SO 2 , HCl, V 2 O 5 , X);

[0066] The fitting formula for the mercury removal active component X is as follows:

[0067] K = f(V2 O 5 , X, S);

[0068] In the above formula, S is the specific surface area at the microscale.

[0069] Obviously, in the above fitting formula, obtaining the amounts of the active components V 2 O 5 and X is the ultimate goal. However, for an unknown catalyst, the amounts of its V 2 O 5 and X are unknown (X is the mercury removal active component, which is usually not contained in commercial catalysts, but it is possible that some catalyst manufacturers add it during production), and the operating conditions are also unknown. The present invention determines the remaining parameters through on-site testing plus laboratory testing, and finally calculates the loadings of the active components V 2 O 5 and X during the regeneration process.

[0070] Optionally, the denitrification activity satisfies the following formula:

[0071] f(V 2 O 5 , X, S 设计 ) > K 1 ;

[0072] In the above formula, K 1 is the target activity, S 设计 is the designed specific surface area of the catalyst, and V 2 O 5 and X are unknowns.

[0073] When calculating the denitrification activity, since catalyst regeneration mainly includes cleaning and loading, the cleaning process is the process in which the ash in the micropores is cleaned and the specific surface area at the microscale is restored; the loading is the process of loading the active components V 2 O 5 . For the known laboratory test results of in-service catalysts, namely the initial activity K 0 and m 0 (V 2 O 5 ), m 0 (X), S 0 , and the target activity K 1 is known (regeneration is generally considered to be able to restore to 90% of the designed activity, that is, K 1 = K 设计 ×0.9).

[0074] Optionally, the mercury oxidation efficiency of a coal-fired power plant is mainly calculated based on the initial mercury concentration in the flue gas and the mercury emission concentration specified in the national air pollutant emission standards. The calculation formula for the mercury oxidation efficiency of a coal-fired power plant is as follows:

[0075]

[0076] Among the above, is the mercury concentration at the reactor inlet element, with the unit of μg / m 3 ; is the mercury emission concentration required by the standard, with the unit of μg / m 3 ; η Hg，目标 is the target mercury oxidation efficiency, with the unit of %.

[0077] In the above embodiment, it is helpful to accurately calculate the mercury oxidation efficiency of a coal-fired power plant.

[0078] Optionally, the mercury oxidation efficiency of a coal-fired power plant shall satisfy:

[0079] f(NH 3 , SO 2 , HCl, V 2 O 5 , X) > η Hg，目标 .

[0080] Through the above analysis, in η = f(NH 3 , SO 2 , HCl, V 2 O 5 , X), η 0 can be calculated, can be obtained through activity calculation, the flue gas components (NH 3 , SO 2 , HCl) are obtained through the pre-regeneration boundary condition test, and the main unknowns in the formula are X and V 2 O 5 .

[0081] Therefore, X and V 2 O 5 shall satisfy the following two inequalities:

[0082] f(V 2 O 5 , X, S 设计 ) > K1;

[0083] f(NH 3 , SO 2 , HCl, V 2 O 5 , X) > η Hg，目标

[0085] After analysis, S 设计 , K 1 , NH 3 , SO 2 , HCl, ηHg，目标 and the functional relationships are all known, and V can be solved for 2 O 5 and the concentration range of X, this concentration is the target value, taking the minimum value, i.e., m 目标,min (V 2 O 5 ), m 目标,min (X) needs to subtract the initial V of the catalyst measured in the laboratory before regeneration 2 O 5 and X values, i.e., m 0 (V 2 O 5 ), m 0 (X), then the denitrification and mercury removal performances can be satisfied simultaneously.

[0086] The final loading amount is:

[0087] m 负载 (V 2 O 5 ) = m 目标,min (V 2 O 5 ) - m 0 (V 2 O 5 );

[0088] m 负载 (X) = m 目标,min (X) - m 0 (X).

[0089] Optionally, the simulated flue gas includes NO, NH 3 , SO 2 , HCl, O 2 and mercury vapor. This helps to accurately simulate the flue gas conditions of the catalyst sample.

[0090] Optionally, in the simulated flue gas, O 2 is sourced from cylinder gas and mercury vapor is sourced from a mercury generator. This helps to accurately control the content of each component in the simulated flue gas.

[0091] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present invention. However, the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims

1. A method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process, characterized in that: The steps include: Step S1, determining the influencing factors of the mercury oxidation efficiency and denitration activity of the catalyst through simulation tests, and obtaining fitting formulas of the denitration active component V2O5 and the demercuration active component X; wherein the influencing factors include flue gas conditions and catalyst components; Step S2, determining the boundary conditions before catalyst regeneration: determining the flue gas conditions for catalyst operation through on-site testing, and determining the initial conditions before catalyst regeneration through sampling and analysis; wherein the initial conditions before catalyst regeneration include the denitration activity of the catalyst and the TiO2 / V2O5 / X content of the catalyst; Step S3, according to the target value of the mercury oxidation efficiency of the catalyst and the target value of the denitration activity, combining the boundary conditions with the fitting formula, obtaining the value ranges of the denitration active component V2O5 and the demercuration active component X; Step S4, taking the minimum value of the denitrification active component V2O5 and the minimum value of the demercuration active component X as the optimal concentration ratio of the catalyst, and combining the initial conditions before the regeneration of the catalyst to obtain the active material loading.

2. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 1, characterized in that: In step S2, the sampling analysis includes activity detection and XRD detection, wherein the activity detection is used to obtain the denitration activity of the catalyst, and the XRD detection is used to obtain the TiO2 / V2O5 / X content.

3. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 2, characterized in that: In step S1, the simulation test includes the following steps: First, a plurality of catalyst samples are prepared by an impregnation method; wherein the components of the catalyst samples include a denitration active component and a demercuration active component, and the ratios of the denitration active component and the demercuration active component of different catalyst samples are different; Then, various catalyst samples are placed in a simulation reactor in turn for simulation test, different simulated flue gases are introduced into the simulation reactor from the inlet of the simulation reactor, and the simulated flue gas is demercurized and denitrated by the catalyst samples; wherein a mercury concentration analyzer and a flue gas concentration analyzer are provided at the inlet and outlet of the simulation reactor, the mercury concentration analyzer is used to measure the mercury concentration, and the flue gas concentration analyzer is used to measure the NO concentration; different simulated flue gases have different flue gas component conditions; Finally, the mercury oxidation efficiency is calculated based on the measured values ​​of the mercury concentration analyzer at the inlet and outlet of the simulated reactor, and the denitrification efficiency is calculated based on the measured values ​​of the flue gas concentration analyzer at the inlet and outlet of the simulated reactor.

4. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 3, characterized in that: The calculation formula for mercury oxidation efficiency in the simulation test is as follows: In the above formula: is the elemental mercury concentration at the reactor inlet, in μg / m 3 ; is the elemental mercury concentration at the outlet of the simulated reactor, in μg / m 3 ; η Hg is the mercury oxidation efficiency, in %.

5. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 4, characterized in that: The calculation formula of denitrification activity K is as follows: K=-Av×ln(1-η NO ); In the above formula, Av is the surface velocity, is the set value; η NO For the denitrification efficiency.

6. The method for calculating the active material loading amount in the denitration catalyst regeneration and mercury removal process according to claim 5, characterized in that: In step S1, the fitting formula of the denitrification active component V2O5 is as follows: η Hg :f(NH3、SO2、HCl,V2O5,X)? The fitting formula of the mercury removal active component X is as follows: K = f(V2O5, X, S); In the above formula, S is the microscopic specific surface area.

7. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 6, characterized in that: The denitrification activity satisfies the following formula: f(V2O5,X,S 设计 )>K1; In the above formula, K1 is the target activity, S 设计 is the design value of the specific surface area of ​​the catalyst.

8. The method for calculating the active material loading amount in the denitration catalyst regeneration and mercury removal process according to claim 7, characterized in that: The mercury oxidation efficiency of a coal-fired power plant is calculated as follows: In the above, is the elemental mercury concentration at the reactor inlet, in μg / m 3 ; is the mercury emission concentration required by the standard, in μg / m 3 ; η Hg，目标 is the target mercury oxidation efficiency, in %.

9. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 8, characterized in that: The mercury oxidation efficiency of coal-fired power plants needs to meet: f(NH3、SO2、HCl,V2O5,X)?η Hg，目标 。 10. The method for calculating the active material loading amount in the denitration catalyst regeneration and demercuration process according to claim 9, characterized in that: The simulated flue gas includes NO, NH3, SO2, HCl, O2 and mercury vapor.

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