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CN-122006736-A - Denitration catalyst, preparation method thereof and removal of NO in sulfur-containing gas phasexIs a method of (2)

CN122006736ACN 122006736 ACN122006736 ACN 122006736ACN-122006736-A

Abstract

The invention relates to a denitration catalyst, a preparation method thereof and a method for removing NO X in a gas phase, and discloses the denitration catalyst which comprises titanium oxide and iron oxide, wherein the molar ratio of Fe element to Ti element on the surface of the catalyst is 5-10:1. The denitration catalyst has the advantages of good low-temperature denitration performance, good sulfur resistance and good operation stability.

Inventors

  • DU CHENHAO
  • CHEN HANGNING
  • LU JIE

Assignees

  • 中国石油化工股份有限公司
  • 中石化（上海）石油化工研究院有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. A denitration catalyst is characterized by comprising titanium oxide and iron oxide, wherein the molar ratio of Fe element to Ti element on the surface of the catalyst is 5-10:1.
  2. 2. The denitration catalyst according to claim 1, wherein, The mole ratio of Fe element to Ti element on the surface of the catalyst is 6-7:1, and/or In the catalyst, the molar ratio of Fe element to Ti element is 50-90:100, preferably 60-70:100.
  3. 3. The denitration catalyst according to claim 1 or 2, wherein the catalyst further contains a modifying element B and/or an element C, wherein the modifying element B is one or more selected from group VB, group VIB and group VIIB elements, and the modifying element C is one or more selected from lanthanoids; preferably, the method comprises the steps of, B element is one or more selected from V, mo, W, mn, and/or The C element is one or more selected from La, ce and Sm, and/or The molar ratio of B element to Ti element is 2-20:100, preferably 5-15:100, and/or The molar ratio of the element C to the element Ti is 1-20:100, preferably 5-15:100.
  4. 4. A denitration catalyst as claimed in any one of claims 1 to 3, wherein, The chemical formula of the catalyst is Ti 100 Fe a B b C d O z , the value range of a is 50-90, preferably 60-70:100, the value range of b is 2-20, preferably 5-15:100, the value range of d is 1-20, preferably 5-15:100, and z is the total number of oxygen atoms required for meeting the valence of each element of the composition; Wherein, the The B element is selected from one or more of VB, VIB and VIIB elements, preferably B element is selected from one or more of V, mo, W, mn, more preferably W, and/or The C element is selected from one or more of lanthanoid elements, preferably one or more of La, ce and Sm, and more preferably La.
  5. 5. A process for preparing a denitration catalyst as claimed in any one of claims 1 to 4, which comprises bringing a mixed solution containing a Ti source, a Fe source, optionally a B source and optionally a C source into contact with an amino acid and a precipitant to carry out coprecipitation, and drying and calcining the obtained precipitate, wherein the condition of coprecipitation comprises pH 5 to 9.
  6. 6. The preparation method as claimed in claim 5, wherein, PH 7-7.5, and/or The precipitant is ammonia water with concentration of 10-20wt%, and/or The total molar ratio of amino acid to metal element in the solution is 0.8-1.2, and/or The amino acid is one or more selected from glycine, alanine, valine, leucine, isoleucine, phenylalanine, tryptophan, tyrosine, aspartic acid, asparagine, glutamic acid, lysine, glutamine, methionine, serine, threonine, cysteine, proline, histidine and arginine, preferably one or more selected from isoleucine, phenylalanine, tryptophan and arginine, more preferably a mixture of isoleucine and arginine, and the dosage of each of the two is not less than 35wt%.
  7. 7. The production method according to claim 5 or 6, wherein the conditions of coprecipitation include: the temperature is 30-80 ℃, preferably 40-60 ℃, and/or the time is 2-10 hours, preferably 4-8 hours.
  8. 8. The process according to any one of claims 5 to 7, wherein the calcination temperature is 300 to 600 ℃, preferably 400 to 500 ℃, and/or the calcination time is 0.5 to 6 hours, preferably 2 to 4 hours.
  9. 9. A process for removing NO x from a sulfur-containing gas phase, which comprises contacting a reducing agent with the sulfur-containing gas phase in the presence of the catalyst according to any one of claims 1 to 4; The conditions of the contacting include: A temperature of 125-300 ℃, preferably 150-250 ℃, more preferably 175-200 ℃, and/or The space velocity of the raw material is 1000-100,000h -1 , preferably 5000-50,000h -1 , and/or The feeding mole ratio of the reducing agent to the sulfur-containing gas phase calculated by NO x is 0.9-1.1:1.
  10. 10. The method of claim 9, wherein, The reducing agent is selected from one or more of ammonia, ammonia water, urea, preferably ammonia and/or ammonia water, and/or The composition of the sulfur-containing gas phase comprises 100-5000ppm of nitrogen oxide, 1-50ppm of SO 2 , 5-20v% of O 2 and the balance of inert gas.

Description

Denitration catalyst, preparation method thereof and method for removing NO x in sulfur-containing gas phase Technical Field The invention relates to the technical field of chemical industry, in particular to a denitration catalyst, a preparation method thereof and a method for removing NO x in a sulfur-containing gas phase. Background Nitrogen oxides (NO x) are a common atmospheric contaminant, and large amounts of NO x are produced during industrial production and fuel combustion, causing serious health and environmental problems. Currently, ammonia selective catalytic reduction (NH 3 -SCR) is considered one of the most effective techniques for eliminating NO x. The technology refers to a process of selectively reducing NO x into N 2 by using a reducing agent NH 3 under the action of a catalyst. When employing NH 3 -SCR technology, it is desirable that the catalyst have a wide operating window to meet the maximum utilization of the catalyst properties under different operating conditions. At present, in the industrial flue gas denitration and purification process, a V-W-TiO 2 catalyst is most common. Generally, the optimal use temperature of the catalyst is above 300 ℃, which causes that under the working condition that the temperature of the flue gas is low, additional supplementary heat is needed to heat the flue gas to the required temperature for reaction, and a great deal of additional energy consumption is caused. In addition, the V-based catalyst has certain biotoxicity, and the country has promoted the development of novel non-vanadium-based denitration catalytic materials in recent years. Therefore, it is of great importance to develop non-vanadium based catalysts that can be used at lower temperatures (< 200 ℃). CN114713243a relates to a low-temperature high-efficiency high-sulfur-resistance long-time stable SCR denitration catalyst and a preparation method thereof. Dissolving nickel salt, manganese salt or manganous salt and a catalyst auxiliary precursor in water to obtain an impregnating solution, impregnating a carrier in the impregnating solution for 10-30min, taking out and drying, weighing after high-temperature roasting, and repeating the processes of impregnating, drying and high-temperature roasting until the total loading amount of the active components and the catalyst auxiliary is 0.001-100% of the mass of the carrier according to the mass percentage to obtain the target catalyst. Disclosure of Invention The invention aims to solve the problems that a V-based catalyst in the prior art has certain biotoxicity (in a denitration catalyst, V generally exists in a relatively high valence state (+5 valence), the valence state V has biotoxicity) and the use temperature is high (the operation temperature of the V-based catalyst is generally above 250 ℃ and the optimal operation temperature is about 300 ℃), and provides a denitration catalyst and a preparation method and application thereof. According to a first aspect of the invention, the invention provides a denitration catalyst, which comprises titanium oxide and iron oxide, wherein the molar ratio of Fe element to Ti element on the surface of the catalyst is 5-10:1. According to a second aspect of the present invention there is provided a process for the preparation of a denitration catalyst according to the present invention, which comprises co-precipitating a mixed solution comprising a Ti source, a Fe source, optionally a B source and optionally a C source by contacting the mixed solution with an amino acid and a precipitant, and drying and calcining the precipitate obtained, wherein the conditions for co-precipitation include a pH of from 5 to 9, preferably from 7 to 7.5. According to a third aspect of the present invention there is provided a process for removing NO x from a sulphur-containing gas phase, which process comprises contacting a reducing agent with the sulphur-containing gas phase in the presence of a catalyst according to the invention. The denitration catalyst has the advantages of good low-temperature denitration performance, good sulfur resistance and good operation stability. Drawings FIG. 1 is a graph showing the variation in the removal effect of nitrogen oxides by the catalyst of example 11 continuously operated for 200 hours under the evaluation test conditions (200 ℃ C.). Detailed Description The endpoints and any values of the ranges disclosed herein are not limited to the precise range or value, and are understood to encompass values approaching those ranges or values. For numerical ranges, one or more new numerical ranges may be found between the endpoints of each range, between the endpoint of each range and the individual point value, and between the individual point value, in combination with each other, and are to be considered as specifically disclosed herein. The invention provides a denitration catalyst which comprises titanium oxide and iron oxide, wherein the molar ratio of Fe element to Ti element