CN111346656A - Regular structure catalyst, preparation method and application thereof, and treatment method of incomplete regenerated flue gas - Google Patents

Regular structure catalyst, preparation method and application thereof, and treatment method of incomplete regenerated flue gas Download PDF

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CN111346656A
CN111346656A CN201811565814.4A CN201811565814A CN111346656A CN 111346656 A CN111346656 A CN 111346656A CN 201811565814 A CN201811565814 A CN 201811565814A CN 111346656 A CN111346656 A CN 111346656A
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catalyst
metal element
regular structure
carrier
content
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CN111346656B (en
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宋海涛
潘罗其
陈正朝
姜秋桥
曹双武
聂白球
杜建文
谭勇
林伟
田辉平
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
Sinopec Baling Co
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Sinopec Research Institute of Petroleum Processing
China Petroleum and Chemical Corp
Sinopec Baling Co
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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/20Carbon compounds
    • B01J27/22Carbides
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/74General processes for purification of waste gases; Apparatus or devices specially adapted therefor
    • B01D53/86Catalytic processes
    • B01D53/8621Removing nitrogen compounds
    • B01D53/8625Nitrogen oxides
    • B01D53/8628Processes characterised by a specific catalyst
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2258/00Sources of waste gases
    • B01D2258/02Other waste gases
    • B01D2258/0283Flue gases
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02CCAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
    • Y02C20/00Capture or disposal of greenhouse gases
    • Y02C20/20Capture or disposal of greenhouse gases of methane

Abstract

The invention relates to the field of catalytic cracking, and discloses a regular structure catalyst for reducing NOx emission in flue gas, a preparation method and application thereof, and a treatment method of incompletely regenerated flue gas, wherein the catalyst comprises the following components in parts by weight: the active component coating comprises an active metal component and a matrix, the active metal component comprises a first metal element and a second metal element, the first metal element is selected from a VIII group non-noble metal element, the first metal element comprises Fe and Co, and the weight ratio of Fe to Co is 1: (0.1-10), and the second metal element is at least one selected from group IA and/or IIA metal elements. The catalyst provided by the invention has high catalytic conversion activity on reduced nitrides, is simple in preparation method, and can effectively reduce the emission of NOx in incompletely regenerated flue gas in catalytic cracking process.

Description

Regular structure catalyst, preparation method and application thereof, and treatment method of incomplete regenerated flue gas
Technical Field
The invention relates to the field of catalytic cracking, in particular to a regular structure catalyst for reducing NOx emission in flue gas, a preparation method and application thereof, and a treatment method of incompletely regenerated flue gas.
Background
The continuous rise of the price of the crude oil greatly increases the processing cost of a refinery, and the refinery reduces the cost by purchasing low-price inferior oil on one hand; on the other hand, the economic benefit is increased by deep processing of heavy oil. Catalytic cracking plays a major role in refineries as an important means for processing heavy oil in refineries, and is not only a main means for balancing heavy oil in refineries and producing clean fuel, but also an attention point for energy conservation and efficiency improvement of refineries. Catalytic cracking is a rapid catalytic reaction system with a catalyst rapidly deactivated, and the problem of catalyst regeneration is always the main line of catalytic cracking development.
In the process of Fluid Catalytic Cracking (FCC), raw oil and a regenerated catalyst are in rapid contact in a riser to carry out catalytic cracking reaction, coke generated by the reaction is deposited on the catalyst to cause the deactivation of the catalyst, the coke-formed deactivated catalyst enters a regenerator after being stripped and contacts with regenerated air or air rich in oxygen entering the bottom of the regenerator to carry out coke-burning regeneration. The regenerated catalyst is circulated back to the reactor to participate in the catalytic cracking reaction again. According to the content of the surplus oxygen in the flue gas in the regeneration process or the sufficient degree of CO oxidation, the catalytic cracking device can be divided into complete regeneration operation and incomplete regeneration operation.
In the complete regeneration process, the coke and the nitrogen-containing compounds in the coke generate CO under the action of regeneration air2And N2And also produces pollutants such as CO and NOx. The use of catalytic promoters is an important technical measure for controlling CO and NOx emission pollution.
An aid for controlling NOx emissions in flue gas regeneration flue gases, commonly referred to as a NOx emission reduction aid or NOx reduction aid, for example CN102371150A discloses a non-noble metal composition for reducing NOx emissions from catalytic cracking regeneration flue gases, said composition having a bulk ratio of not more than 0.65 g/ml and comprising, in terms of oxides based on the weight of the composition: (1)50-99 wt% of inorganic oxide carrier, (2)0.5-40 wt% of one or more non-noble metal elements selected from IIA, IIB, IVB and VIB, and (3)0.5-30 wt% of rare earth elements. The composition is used for fluidized catalytic cracking, and can remarkably reduce the emission of NOx in regeneration flue gas.
During incomplete regeneration, the flue gas from the regenerator has a very low NOx concentration and reduced nitrides such as NH due to low excess oxygen content and high CO concentration3And higher concentration of HCN and the like. These reduced nitrides flow downstream with the flue gas, and if sufficiently oxidized, NO is produced in the CO boiler for energy recoveryx; if not sufficiently oxidized, residual NH3The ammonia nitrogen content of the wastewater of the downstream washing tower exceeds the standard or is easy to cause the SO in the flue gasxThe ammonium salt generated by the reaction is separated out, so that salt deposition is caused in a waste boiler or other flue gas post-treatment equipment (such as SCR), and the long-period operation of the device is influenced. Thus, the incomplete regeneration process catalytically converts NH in the regenerator using a catalyst promoter3And the NOx emission in the flue gas can be reduced, and the operation period of the device is prolonged.
US5021144 discloses a method for reducing NH in flue gas of incomplete regeneration FCC device3The method of discharging is to add excess CO combustion improver into the regenerator in an amount 2-3 times the minimum addition to prevent lean bed afterburning. The method can reduce NH in flue gas of incomplete regeneration FCC device3But the emission is large, the energy consumption is high, and the environmental protection is not facilitated.
US4755282 discloses a process for reducing NH in flue gas of a partially or incompletely regenerated FCC unit3A method of venting. The method comprises adding ammonia decomposition catalyst with particle size of 10-40 μm into regenerator, maintaining the catalyst in dilute phase bed layer at a certain concentration, and adding NH3Conversion to N2And water. The active component of the ammonia decomposition catalyst may be a noble metal dispersed on an inorganic oxide support.
CN101024179A discloses a NOx reducing composition for use in FCC processes comprising (i) an acidic metal oxide substantially free of zeolite, (ii) an alkali metal, an alkaline earth metal and mixtures thereof and (iii) an oxygen storage component. The prepared composition is impregnated by noble metal to convert gas phase reduced nitrogen substances in the flue gas of an incomplete regeneration catalytic cracking unit and reduce the emission of NOx in the flue gas.
Currently, for controlling the flue gas NH of incomplete regenerators3And NOx emission catalyst technology research and application reports are relatively few, and because the difference between the smoke composition of an incomplete regeneration device and a complete regeneration device is obvious, the existing catalytic auxiliary agent suitable for the complete regeneration device has an undesirable application effect on the incomplete regeneration device. The adjuvant compositions disclosed in the above-mentioned techniques can be used to some extentCatalytic conversion of NH in flue gas3Nitride in reduced state, but for NH in flue gas3The catalytic conversion activity of the nitride in reduced state is still to be improved to slow down NH3And the influence of deposited salt on the operation of equipment is avoided, so that a flue gas pollutant emission reduction catalyst system suitable for an incomplete regeneration device needs to be developed, and the emission of flue gas NOx is further reduced.
Disclosure of Invention
Aiming at NH in the regeneration process, particularly in the incomplete regeneration process in the prior art3The invention provides a regular structure catalyst for reducing NOx emission in flue gas, a preparation method and application thereof, and a treatment method of incompletely regenerated flue gas. The regular structure catalyst for reducing the NOx emission in the flue gas provided by the invention has high catalytic conversion activity on reduced nitrides, is simple in preparation method, and can effectively reduce the NOx emission in the incompletely regenerated flue gas in the catalytic cracking process.
In order to achieve the above object, a first aspect of the present invention provides a structured catalyst for reducing NOx emissions in flue gas, the catalyst comprising: the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier, wherein the content of the active component coating is 10-50 wt% based on the total weight of the catalyst; the active component coating contains an active metal component and a substrate, the active metal component comprises a first metal element and a second metal element, the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the weight ratio of Fe to Co is 1: (0.1-10), and the second metal element is at least one selected from group IA and/or IIA metal elements.
A second aspect of the invention provides a method of preparing a structured catalyst for reducing NOx emissions in flue gases, the method comprising:
(1) mixing and pulping a substrate source, a first metal element precursor, a second metal element precursor and water to obtain active component coating slurry;
(2) coating a regular structure carrier with the active component coating slurry, and drying and roasting to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier;
the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the second metal element is selected from at least one of metal elements in IA and/or IIA groups;
in the first metal element precursor, the use amounts of the precursor of Fe and the precursor of Co are such that, in the prepared catalyst, the weight ratio of Fe to Co is 1: (0.1-10).
According to a third aspect of the present invention, there is provided a structured catalyst for reducing NOx emissions in flue gases made by the above method.
According to a fourth aspect of the present invention, there is provided the use of the above structured catalyst for reducing NOx emissions in flue gas in catalytic cracking incompletely regenerated flue gas treatment.
According to a fifth aspect of the present invention, there is provided a method for treating incomplete regeneration flue gas, the method comprising: the incompletely regenerated flue gas is contacted with a catalyst, and the catalyst is the regular structure catalyst for reducing the emission of NOx in the flue gas.
Preferably, the contacting is performed in a flue gas channel provided in front of the CO incinerator and/or the CO incinerator, further preferably in a flue gas channel provided in front of the CO incinerator.
Compared with the prior art, the regular structure catalyst for reducing the NOx emission in the flue gas provided by the invention has the following technical effects:
(1) in the regular structure catalyst, the specific kind of active components are distributed on the inner/outer surface of the regular structure catalyst in a coating mode, the dispersion degree of active metals in the coating is higher, and the catalyst has high activity on NH3The catalytic conversion activity of the nitride in the reduced state is obviously improved;
(2) the method for treating the incomplete regeneration flue gas can effectively reduce the emission of NOx in the incomplete regeneration flue gas by adopting the catalyst with the regular structure,preferably, the catalyst and the incompletely regenerated flue gas are carried out in a flue gas channel arranged in front of the CO incinerator and/or the CO incinerator, and further preferably in a flue gas channel arranged in front of the CO incinerator, so that NH is more favorably treated3The catalytic conversion activity of the reduced nitrides is improved, and the distribution of FCC products is not influenced at all.
Drawings
FIG. 1 is an XRD pattern of the structured catalyst for reducing NOx emissions in flue gas prepared in examples 1 and 4.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In the present invention, the term "structured catalyst" is used to mean a catalyst comprising a structured carrier and a coating of an active component distributed on the inner and/or outer surface of the carrier; a "regular structure vector" is a vector having a regular structure.
In a first aspect, the present invention provides a structured catalyst for reducing NOx emissions in flue gas, the catalyst comprising: the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier, wherein the content of the active component coating is 10-50 wt% based on the total weight of the catalyst; the active component coating contains an active metal component and a substrate, the active metal component comprises a first metal element and a second metal element, the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the weight ratio of Fe to Co is 1: (0.1-10), and the second metal element is at least one selected from group IA and/or IIA metal elements.
The invention provides a regular knotIn the structured catalyst, active component first metal elements (including Fe and Co) and second metal elements exist on the inner surface and/or the outer surface of a carrier with a regular structure in the form of active metal component coatings, the dispersity of active metals in the coatings is high, and NH is treated3The catalytic conversion activity of the nitride in the reduced state is obviously improved.
According to a preferred embodiment of the present invention, the active component coating is present in an amount of 15 to 40 wt. -%, preferably 20 to 35 wt. -%, most preferably 20 to 30 wt. -%, based on the total weight of the catalyst.
According to the structured catalyst provided by the invention, preferably, the content of the matrix is 50-90 wt% based on the total weight of the active component coating, the content of the first metal element is 3-30 wt% and the content of the second metal element is 1-20 wt% calculated by oxide.
Further preferably, the content of the substrate is 60 to 90 wt%, the content of the first metal element is 5 to 25 wt%, and the content of the second metal element is 2 to 15 wt%, calculated as an oxide, based on the total weight of the active component coating.
Still more preferably, the content of the substrate is 72 to 85 wt%, the content of the first metal element is 10 to 16 wt%, and the content of the second metal element is 5 to 12 wt%, calculated as an oxide, based on the total weight of the active component coating layer.
In the invention, the contents of all components in the catalyst with the regular structure are measured by adopting an X-ray fluorescence spectrum analysis method (a petrochemical engineering analysis method (RIPP experimental method), compilation of Yangcui and the like, published by scientific publishing company in 1990).
The first metal element comprises Fe and Co, and the invention does not exclude that the first metal element also comprises elements other than Fe and Co in the VIII group non-noble metal elements, such as Ni.
In the present invention, the first metal element may contain Fe and Co as long as it can increase NH content of the catalyst3The catalytic conversion activity of the nitride in an isoreduced state is preferably such that the synergistic effect of Fe and Co is further exhibitedAnd the weight ratio of Fe to Co calculated by oxide is 1: (0.3-3), more preferably 1: (0.4-2).
In the present invention, unless otherwise specified, Fe in terms of oxide means Fe in terms of Fe2O3In terms of Co in oxide, Co means Co in Co2O3And (6) counting.
According to a preferred embodiment of the invention, the Fe in the catalyst is at least partially present in the form of iron carbide, preferably Fe3C and/or Fe7C3. The amount of iron carbide present is not particularly limited in the present invention, and the performance of the structured catalyst can be effectively improved as long as part of the iron carbide is present.
According to a preferred embodiment of the invention, the Co of the catalyst is at least partly present in the form of elemental cobalt. The invention has no special limitation on the existing amount of the simple substance cobalt, and the performance of the regular structure catalyst can be effectively improved as long as part of the simple substance cobalt is present.
It should be noted that the prior art provides catalysts in which the metal element is mostly present in the form of oxidation state. In the preparation process of the catalyst, a roasting mode is preferably adopted in a carbon-containing atmosphere, so that part of FeO is converted into iron carbide, and part of CoO is converted into simple substance cobalt. The inventor of the invention finds that the existence of the iron carbide and/or the simple substance cobalt can enable the catalyst to better promote the decomposition of the nitrogen-containing compound in a reduction state, reduce the generation of nitrogen oxides and promote the reduction of the nitrogen oxides to a certain extent.
According to the structured catalyst provided by the invention, preferably, the XRD pattern of the catalyst has diffraction peaks at 42.6 degrees, 44.2 degrees and 44.9 degrees of 2 theta.
Specifically, diffraction peaks of iron carbide at 42.6 ° and 44.9 ° of 2 θ; the diffraction peak of the simple substance cobalt is at 44.2 degrees 2 theta.
According to a preferred embodiment of the present invention, the catalyst provided by the present invention has an XRD pattern in which the diffraction peak at 44.9 ° 2 θ is stronger than the diffraction peak at 42.6 ° 2 θ.
In the invention, the structured catalyst adopts an X-ray diffractometer (Siemens company D5005 type) to obtain an XRD spectrogram and carry out structure determination, and the specific conditions comprise a Cu target, K α radiation, a solid detector, a tube voltage of 40kV and a tube current of 40 mA.
In the present invention, the group IA metal elements include, but are not limited to, Na and/or K; the group IIA metal element includes, but is not limited to, at least one of Mg, Ca, Sr, and Ba.
According to the structured catalyst provided by the present invention, preferably, the second metal element is at least one selected from Na, K, Mg and Ca, more preferably K and/or Mg, and most preferably Mg.
According to a most preferred embodiment of the present invention, the NH content of the catalyst with a regular structure can be greatly increased by using Fe, Co and Mg as active components3The catalytic conversion activity of the reduced nitrides is equal, and the regular structure catalyst has more excellent hydrothermal stability.
According to a most preferred embodiment of the present invention, the catalyst comprises: the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier, wherein the content of the active component coating is 10-50 wt% based on the total weight of the catalyst; the active component coating contains Fe, Co, Mg and alumina, and the weight ratio of Fe to Co is 1: (0.4-2), based on the total weight of the active component coating, the content of alumina is 72-85 wt%, the total content of Fe and Co is 10-16 wt% and the content of Mg is 5-12 wt% calculated by oxide.
According to the regular structure catalyst provided by the invention, preferably, the matrix is selected from at least one of alumina, silica-alumina, zeolite, spinel, kaolin, diatomite, perlite and perovskite, preferably at least one of alumina, spinel and perovskite, and is further preferably alumina.
The structured catalyst according to the present invention, wherein the structured carrier can be used in a catalyst bed provided in a fixed bed reactor. The regular structure carrier can be a whole carrier block, a hollow pore channel structure is formed inside the regular structure carrier, a catalyst coating can be distributed on the inner wall of a pore channel, and the pore channel space can be used as a flowing space of fluid. Preferably, the structured support is selected from monolithic supports having a parallel cell structure with open ends. The regular structure carrier can be a honeycomb type regular carrier (honeycomb carrier for short) with honeycomb-shaped open pores on the cross section.
According to the structured catalyst of the present invention, the structured carrier preferably has a pore density of 20 to 900 pores per square inch, preferably 20 to 300 pores per square inch, in cross section; the open porosity of the cross section of the structured carrier is 20 to 80%, preferably 50 to 80%. The holes can be regular or irregular, and the holes can be the same or different in shape and can be independent of each other and can be one of square, regular triangle, regular hexagon, circle and ripple.
According to the structured catalyst of the present invention, preferably, the structured carrier may be at least one selected from the group consisting of cordierite honeycomb carrier, mullite honeycomb carrier, diamond honeycomb carrier, corundum honeycomb carrier, zircon corundum honeycomb carrier, quartz honeycomb carrier, nepheline honeycomb carrier, feldspar honeycomb carrier, alumina honeycomb carrier and metal alloy honeycomb carrier.
In a second aspect, the present invention provides a method for preparing a structured catalyst for reducing NOx emissions in flue gases, the method comprising:
(1) mixing and pulping a substrate source, a first metal element precursor, a second metal element precursor and water to obtain active component coating slurry;
(2) coating a regular structure carrier with the active component coating slurry, and drying and roasting to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier;
the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the second metal element is selected from at least one of metal elements in IA and/or IIA groups;
in the first metal element precursor, the use amounts of the precursor of Fe and the precursor of Co are such that, in the prepared catalyst, the weight ratio of Fe to Co is 1: (0.1-10).
In the present invention, specifically, the matrix source is a substance that can be converted into a matrix under the conditions of the firing in step (2). The present invention is not particularly limited in this regard. The kind of the substrate is as described above, and is not described in detail herein. When the substrate is preferably alumina, the substrate source may be a precursor to alumina, for example the substrate source is selected from at least one of gibbsite, surge dawsonite, nordstrandite, diaspore, boehmite and pseudoboehmite, most preferably pseudoboehmite.
According to the method provided by the invention, before pulping, the matrix source is preferably subjected to acidification peptization treatment, the acidification peptization treatment can be carried out according to the conventional technical means in the field, and further preferably, the acid used in the acidification peptization treatment is hydrochloric acid.
The selection range of the acidification peptization conditions is wide, and preferably, the acidification peptization conditions comprise: the acid-aluminum ratio is 0.12-0.22: 1, the time is 10-40 min.
In the present invention, the aluminum acid ratio refers to a mass ratio of hydrochloric acid calculated as 36% by weight of concentrated hydrochloric acid to a precursor of alumina on a dry basis, unless otherwise specified.
According to the present invention, the first metal element precursor and the second metal element precursor are respectively selected from water-soluble salts of the first metal element and the second metal element, such as nitrate, chloride, chlorate, sulfate, and the like, and the present invention is not particularly limited thereto.
According to the method provided by the present invention, the structured carrier and the first metal element and the second metal element are selected as described above, and are not described herein again.
In the present invention, preferably, the solid content of the active component coating slurry of step (1) is 8 to 30% by weight.
According to the method provided by the present invention, there is no particular limitation on the method for mixing and beating the substrate source, the first metal element precursor, the second metal element precursor and water, and the order of adding the substrate source, the first metal element precursor and the second metal element precursor is also not limited as long as the substrate source, the first metal element precursor, the second metal element precursor and water are contacted, preferably, the first metal element precursor is dissolved in water, then the substrate source (preferably, an acidified substrate source) is added to obtain the first solution, the second metal element precursor is mixed with water to obtain the second solution, finally, the first solution and the second solution are mixed, and then beating is performed to obtain the slurry.
In the invention, the roasting can effectively improve the NH of the catalyst with the regular structure by adopting the conventional technical means in the field3The catalytic conversion activity of the reduced nitrides is equal, but in order to further increase the NH of the catalysts with regular structures3The catalytic conversion activity and hydrothermal stability of the nitride in an isoreduced state, and preferably the calcination is carried out in a carbon-containing atmosphere. The inventor of the invention unexpectedly discovers in the research process that the calcination is carried out in a carbon-containing atmosphere, so that the regular structure catalyst can react on NH3The catalytic conversion activity and the hydrothermal stability of the nitride in the reduced state are both obviously improved. The improvement of activity may be related to the conversion of active components from oxides to carbides and to the reduction state, while the improvement of hydrothermal stability may be related to the fact that the high temperature treatment further promotes the adhesion, fusion and crosslinking of the active components in the catalyst. It can be seen from the XRD contrast spectrum that the obvious iron carbide peak pattern and the peak pattern of the simple substance cobalt appear after the treatment. Specifically, as shown in FIG. 1, the XRD spectrum of the regular structure catalyst S-4 which has not been subjected to the carbon-containing atmosphere treatment has a diffraction peak of MgO at about 43.0 degrees and Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4The XRD spectrum of the regular structure catalyst S-1 treated by the carbon-containing atmosphere has a diffraction peak of MgO at about 43.0 degrees and Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And diffraction peaks at about 43.0 ° and at about 45.0 ° are significantly stronger and shifted to the left, due to the gauge treated in a carbon-containing atmosphereThe diffraction peaks of the catalyst S-1 with the whole structure appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-1 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4. In the regular structure catalyst S-1 treated by the carbon-containing atmosphere, part of cobalt oxide is converted into simple substance cobalt.
It should be noted that FIG. 1 shows only XRD patterns in the range of 41 to 50, which is mainly used to illustrate the presence of Fe and Co in the structured catalyst. Outside the range of 41 ° to 50 °, other diffraction peaks are present, for example, diffraction peaks for FeO (at 37 °, 65 ° and 59 ° for 2 θ) and CoO (at 37 °, 65 ° and 31 ° for 2 θ), which are not further explained by the present invention.
According to a preferred embodiment of the present invention, the conditions of the calcination include: the reaction is carried out in a carbon-containing atmosphere at the temperature of 400-1000 ℃, preferably 450-650 ℃ and the time of 0.1-10h, preferably 1-3 h.
In the present invention, the pressure for the calcination is not particularly limited, and the calcination may be carried out under normal pressure. For example, it can be carried out at 0.01 to 1MPa (absolute pressure).
In the present invention, the carbon-containing atmosphere is provided by a gas containing a carbon-containing element, and the carbon-containing gas is preferably selected from carbon-containing gases having reducing properties, further preferably at least one of CO, methane and ethane, and most preferably CO.
According to the present invention, the gas containing carbon element may further contain a part of inert gas, and the inert gas may be various inert gases conventionally used in the art, and is preferably at least one selected from nitrogen, argon and helium, and is further preferably nitrogen.
According to a preferred embodiment of the present invention, the carbon-containing atmosphere is provided by a mixed gas containing CO and nitrogen, and the volume concentration of CO in the carbon-containing atmosphere is preferably 1 to 20%, and more preferably 4 to 10%. By adopting the preferred embodiment of the invention, the treatment requirements can be better met, and the safety of operators can be ensured.
In the present invention, the calcination may be performed in a calciner, which may be a rotary calciner used in the production of catalytic cracking catalysts and promoters. The gas containing carbon element is in countercurrent contact with the solid material in the roasting furnace.
The drying conditions in step (2) are not particularly limited in the present invention, and may be performed according to the conventional techniques in the art, for example, the drying conditions in step (2) may include: the temperature is 60-150 ℃ and the time is 2-10 h.
According to the method of the present invention, preferably, the coating is performed such that the catalyst is obtained in an amount of 10 to 50 wt%, preferably 15 to 40 wt%, more preferably 20 to 35 wt%, and most preferably 20 to 30 wt%, based on the total amount of the catalyst. On the basis of the content, the content of the active component coating can be adjusted by controlling parameters in the coating process by the skilled person, for example, the amount of the active component coating slurry and the structured carrier in the coating process.
The coating in the method provided by the invention can be realized by coating the active component coating slurry on the inner surface and/or the outer surface of the regular structure carrier by adopting various coating methods; the coating method may be a water coating method, a dipping method or a spraying method. The specific operation of coating can be carried out with reference to the method described in CN 1199733C. Preferably, the coating is a water coating method, one end of the regular structure carrier is immersed in the active component coating slurry in the coating process, and the other end of the regular structure carrier is subjected to vacuum so that the active component coating slurry continuously passes through the pore channels of the regular structure carrier. The volume of the active component coating slurry passing through the pore channel of the regular structure carrier can be 2-20 times of the volume of the regular structure carrier, the applied vacuum pressure can be-0.1 MPa (MPa) to-0.01 MPa (MPa), the coating temperature can be 10-70 ℃, and the coating time can be 0.1-300 seconds. And drying the regular structure carrier coated with the active component coating slurry to obtain the active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier.
The selection range of the use amounts of the substrate source, the first metal element precursor and the second metal element precursor is wide, and preferably, the use amounts of the substrate source, the first metal element precursor and the second metal element precursor are such that the content of the substrate in the prepared catalyst is 50-90 wt%, the content of the first metal element is 3-30 wt% and the content of the second metal element is 1-20 wt% in terms of oxide, based on the total weight of the active component coating; preferably, the content of the substrate is 60-90 wt%, the content of the first metal element is 5-25 wt% and the content of the second metal element is 2-15 wt% calculated by oxide, based on the total weight of the active component coating; further preferably, the content of the substrate is 72 to 85 wt%, the content of the first metal element is 10 to 16 wt%, and the content of the second metal element is 5 to 12 wt%, calculated as an oxide, based on the total weight of the active component coating.
According to the method provided by the invention, preferably, the mass ratio of the matrix source calculated by oxide, the first metal element precursor calculated by VIII group non-noble metal element oxide and the second metal element precursor calculated by IA and/or IIA group metal element oxide is 50-90: 3-30: 1 to 20; further, it may be 60 to 90: 5-25: 2-15; still further, it may be 72-85: 10-16: 5-12.
According to a preferred embodiment of the present invention, the Fe precursor and the Co precursor are used in amounts such that, in the resulting catalyst, the weight ratio of Fe to Co, calculated as oxides, is preferably 1: (0.3-3), more preferably 1: (0.4-2).
In a third aspect, the invention provides a structured catalyst prepared by the method for reducing NOx emission in flue gas. The catalyst comprises: the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier, wherein the content of the active component coating is 10-50 wt% based on the total weight of the catalyst; the active component coating contains an active metal component and a substrate, the active metal component comprises a first metal element and a second metal element, the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the weight ratio of Fe to Co is 1: (0.1-10), and the second metal element is at least one selected from group IA and/or IIA metal elements. The structured catalyst prepared by the method of the present invention has the same technical features as the structured catalyst claimed in the present invention, and the specific contents refer to the previous description of the structured catalyst of the present invention.
The regular structure catalyst for reducing NOx emission in flue gas provided by the invention is suitable for various working conditions, the catalytic conversion activity of reduced nitride is high, the hydrothermal stability is good, the preparation method is simple, and the regular structure catalyst is used in a catalytic cracking process and can effectively reduce the NOx emission in incompletely regenerated flue gas of catalytic cracking. Therefore, the fourth aspect of the present invention provides the use of the above structured catalyst for reducing NOx emissions in flue gas in the treatment of catalytic cracking incompletely regenerated flue gas.
The fifth aspect of the invention provides a method for treating incomplete regeneration flue gas, which comprises the following steps: the incomplete regeneration flue gas is contacted with a catalyst, and the catalyst is a regular structure catalyst for reducing the emission of NOx in the incomplete regeneration flue gas.
The composition of the incomplete regeneration flue gas is not particularly limited, and the incomplete regeneration flue gas can be obtained by an incomplete regeneration catalytic cracking unit, preferably, O in the incomplete regeneration flue gas2Is not more than 0.1% by volume, CO is not less than 4% by volume, NH3Is not less than 200ppm, and the NOx content is not more than 10 ppm. During incomplete regeneration, the flue gas from the regenerator has a very low NOx concentration and reduced nitrides such as NH due to low excess oxygen content and high CO concentration3And higher concentration of HCN and the like. These reduced nitrides flow downstream along with the flue gas, and are sufficiently oxidized in the CO incinerator for energy recovery, resulting in the formation of NOx. Based on this, preferably, the contact of the incompletely regenerated flue gas with the catalyst is carried out before the CO incinerator and/or the CO incineratorThe flue gas channel is arranged to remove the reduced nitride before it is oxidized. In the CO incinerator, air supply is generally performed, reduced nitrides are easily oxidized without using a catalyst to generate NOx, and in order to prevent the reduced nitrides from being oxidized, it is preferable that the contact is performed at the front of the CO incinerator when the contact is performed in the CO incinerator. Most preferably, the contact between the incompletely regenerated flue gas and the catalyst is carried out in a flue gas channel arranged in front of the CO incinerator, namely, the catalyst is placed in the flue gas channel arranged in front of the CO incinerator, the incompletely regenerated flue gas is in an oxygen-deficient state in the flue gas channel, and the contact between the incompletely regenerated flue gas and the catalyst in the flue gas channel is more favorable for NH3Catalytic conversion of the iso-reduced nitrides.
The catalyst for incompletely regenerated flue gas provided in the prior art exists in a fluidized bed layer of a catalytic cracking regenerator in the form of catalyst promoter microspheres, and the flue gas is fully contacted with the catalyst to realize the effect of reducing NOx emission.
In the present invention, the ppm refers to a volume concentration unless otherwise specified.
The CO incinerator is not particularly limited, and various types of CO incinerators conventionally used in the art, such as a vertical type CO incinerator or a horizontal type CO incinerator, may be used.
According to the present invention, preferably, the conditions of the contacting include: the temperature is 600-1000 ℃, the reaction pressure is 0-0.5MPa and the mass space velocity of the flue gas is 10-1000h based on gauge pressure-1Further preferably, the contacting conditions include: the temperature is 650 plus one year, the pressure is 0.1-0.3MPa, the mass space velocity of the flue gas is 30-500h-1. In the present invention, the mass space velocity of the flue gas is, without particular limitation, the mass of the flue gas passing through the active component coating per unit mass per unit time, in terms of the active component coating of the structured catalyst.
Preferably, the structured catalyst is present in the form of a catalyst bed. In the method for treating the incompletely regenerated flue gas, the regular structure catalyst can be used as a fixed catalyst bed layer to be arranged in a flue gas channel arranged in front of a CO incinerator and/or a CO incinerator, and the flowing incompletely regenerated flue gas can flow through the regular structure catalyst bed layer, namely can flow through a pore channel in a regular structure carrier and react with an active component coating distributed on the wall of the pore channel.
According to the method provided by the invention, an energy recovery process can be further included, the energy recovery process can be carried out according to conventional technical means in the field, and specifically, partial catalyst fine powder carried by incomplete regeneration flue gas obtained by an incomplete regeneration catalytic cracking device is separated by a cyclone separator (preferably sequentially passing through a secondary cyclone separator and a tertiary cyclone separator), and then the incomplete regeneration flue gas is sent to a flue gas turbine, the flue gas turbine is connected with a main fan, the flue gas turbine expands to do work to drive the main fan to recover pressure energy and heat energy in the incomplete regeneration flue gas, and the incomplete regeneration flue gas after energy recovery by the flue gas turbine is sent to a CO incinerator.
The following detailed description is provided for the purpose of illustrating the embodiments and the advantageous effects thereof, and is intended to help the reader to clearly understand the spirit of the present invention, but not to limit the scope of the present invention.
In the following examples, the contents of the components in the structured catalyst for reducing NOx emission in flue gas were measured by X-ray fluorescence spectroscopy (XRF), which is specifically described in the literature of petrochemical analysis (RIPP test), and published by the scientific press in 1990, compiled by yangchini et al.
In the embodiment, the regular structure catalyst for reducing NOx emission in flue gas is subjected to structure measurement by adopting an X-ray diffractometer (Siemens company D5005 type), and an XRD spectrogram is obtained, specifically, 1g of the active component coating on the outer surface of the regular structure catalyst is taken and ground to be used as a sample, a Cu target, K α radiation, a solid detector, a tube voltage of 40kV and a tube current of 40 mA.
The raw materials used in the examples and comparative examples: cobalt nitrate [ Co (NO)3)2·6H2O]For analytical purposes, ferric nitrate [ Fe (NO)3)3·9H2O]For analytical purity, magnesium oxide [ MgO]For analytical purification, it is made by the group of national medicineManufactured by reagent limited; pseudo-boehmite is an industrial grade product, the content of alumina is 64 weight percent, and the pore volume is 0.31 ml/g, which is produced by Shandong aluminum company; hydrochloric acid with the concentration of 36.5 weight percent, and the product is analytically pure and produced by Beijing chemical plants; carbon monoxide with a concentration of 10 vol%, nitrogen as a balance gas, produced by Beijing helium Pubei gas industries, Ltd.
The coating method in the following examples and comparative examples is a water coating method, and the specific process method comprises the following steps: in each coating process, one end of the regular structure carrier is immersed in the active component coating slurry, and the other end of the regular structure carrier is vacuumized, so that the active component coating slurry continuously passes through the pore channel of the regular structure carrier; the vacuum pressure applied was-0.03 MPa (MPa) and the temperature of coating was 35 ℃.
Example 1
(1) Adding 265g of pseudo-boehmite into 1.42kg of deionized water, pulping and dispersing, then adding 23.8mL of hydrochloric acid, acidifying for 15min to obtain aluminum-aluminum colloid, and adding ferric nitrate (calculated as Fe) calculated by metal oxide2O3Calculated as Co) 10g, cobalt nitrate (calculated as Co)2O3Metering) 10g of the aluminum-based composite material is added into 350mL of water and stirred until the aluminum-based composite material is fully dissolved, and the aluminum-based composite material is added into the water and stirred for 15min to obtain a first solution; adding 10g of MgO into 36g of water, stirring for 10min, adding into the first solution, and stirring for 20min to obtain active component coating slurry;
(2) coating a cordierite honeycomb carrier (the carrier has a pore density of 400 pores/square inch, an open porosity of a cross section of 70% and a square shape) with the active component coating slurry obtained in the step (1), drying (100 ℃, 4 hours), transferring the carrier into a tube furnace, and introducing CO/N with a CO concentration of 10 vol% at a flow rate of 100mL/min2And treating the mixed gas at 600 ℃ for 1.5h to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier to obtain the regular structure catalyst S-1, wherein the content of the active component coating is 25 wt% based on the total weight of the regular structure catalyst.
The measurement results of the contents of the components in the active component coating of the catalyst S-1 with the regular structure are shown in Table 1.
X for catalyst S-1 of regular structureThe XRD spectrum is shown in FIG. 1, and it can be seen from FIG. 1 that the XRD spectrum of the regular structure catalyst S-4 which has not been treated with the carbon-containing atmosphere has a diffraction peak of MgO at about 43.0 DEG and Al at about 45.0 DEG2O3、Co2AlO4And MgAl2O4The XRD spectrum of the regular structure catalyst S-1 treated by the carbon-containing atmosphere has a diffraction peak of MgO at about 43.0 degrees and Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-1 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-1 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4. In the regular structure catalyst S-1 treated by the carbon-containing atmosphere, part of cobalt oxide is converted into simple substance cobalt.
It should be noted that FIG. 1 shows only XRD patterns in the range of 41 to 50, which is mainly used to illustrate the presence of Fe and Co in the structured catalyst. Outside the range of 41-50 degrees, other diffraction peaks exist, for example, diffraction peaks of FeO (2 theta is at 37 degrees, 65 degrees and 59 degrees) and CoO (2 theta is at 37 degrees, 65 degrees and 31 degrees), and diffraction peaks outside the range of 41-50 degrees are not related to diffraction peaks of FeC and simple substance Co, and the invention does not carry out further spectrum analysis.
Example 2
(1) Adding 256g of pseudo-boehmite into 1.39kg of deionized water, pulping and dispersing, then adding 23.2mL of hydrochloric acid, acidifying for 15min to obtain an aluminum-aluminum colloid, and adding ferric nitrate (calculated as Fe) calculated by metal oxide2O3Calculated as Co) 14g, cobalt nitrate (calculated as Co)2O3Metering) 6g of the aluminum oxide colloid is added into 350mL of water and stirred until the aluminum oxide colloid is fully dissolved, and the aluminum oxide colloid is added into the water and stirred for 15min to obtain a first solution; adding 16g MgO into 48g water, stirring for 10min, adding into the first solution, stirring for 20min to obtain active component coatingLayer slurry;
(2) coating a cordierite honeycomb carrier (the carrier has a pore density of 400 pores/square inch, an open porosity of a cross section of 70% and a square shape) with the active component coating slurry obtained in the step (1), drying (100 ℃, 4 hours), transferring the carrier into a tube furnace, and introducing CO/N with a CO concentration of 10 vol% at a flow rate of 100mL/min2And treating the mixed gas at 500 ℃ for 3h to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier to obtain the regular structure catalyst S-2, wherein the content of the active component coating is 30 wt% based on the total weight of the regular structure catalyst.
The measurement results of the contents of the components in the active component coating of the catalyst S-2 with the regular structure are shown in Table 1.
XRD analysis of the regular structure catalyst S-2 was similar to that of example 1. In XRD spectrogram of regular structure catalyst S-2 treated by carbon-containing atmosphere, there are not only MgO diffraction peak at about 43.0 degrees, but also Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-2 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-2 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Example 3
(1) Adding 225g of pseudo-boehmite into 1.39kg of deionized water, pulping and dispersing, then adding 20.4mL of hydrochloric acid, acidifying for 15min to obtain aluminum-aluminum colloid, and adding ferric nitrate (calculated as Fe) calculated as metal oxide2O3Calculated as Co) 20g, cobalt nitrate (calculated as Co)2O3Metering) 12g of the aluminum-based composite material is added into 350mL of water and stirred until the aluminum-based composite material is fully dissolved, and the aluminum-based composite material is added into the water and stirred for 15min to obtain a first solution; adding 24g MgO into 72g water, stirring for 10min, adding into the first solution, and stirring for 20min to obtain activityA component coating slurry;
(2) coating a cordierite honeycomb carrier (the carrier has a pore density of 400 pores/square inch, an open porosity of a cross section of 70% and a square shape) with the active component coating slurry obtained in the step (1), drying (100 ℃, 4 hours), transferring the carrier into a tube furnace, and introducing CO/N with a CO concentration of 10 vol% at a flow rate of 100mL/min2And treating the mixed gas at 650 ℃ for 1h to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier to obtain the regular structure catalyst S-3, wherein the content of the active component coating is 20 wt% based on the total weight of the regular structure catalyst.
The measurement results of the contents of the components in the active component coating of the catalyst S-3 with the regular structure are shown in Table 1.
XRD analysis of the regular structure catalyst S-3 showed a similarity to that of example 1. In XRD spectrogram of regular structure catalyst S-3 treated in carbon-containing atmosphere, there are not only MgO diffraction peak at about 43.0 degrees, but also Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-3 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-3 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Example 4
The procedure is as in example 1, except that the CO concentration is 10% by volume CO/N2And replacing the mixed gas with air to obtain the catalyst S-4 with a regular structure.
The results of measuring the contents of the respective components in the regular structure catalyst S-4 are shown in Table 1. XRD analysis is carried out on the regular structure catalyst S-4, and from an XRD spectrogram (shown in figure 1), no obvious diffraction peaks exist at positions with 2 theta of 42.6 degrees, 44.2 degrees and 44.9 degrees, which proves that both Fe and Co in the regular structure catalyst S-4 exist in an oxide form.
Example 5
A structured catalyst S-5 was obtained by following the procedure of example 1, except that MgO was replaced with CaO of the same mass.
The results of measuring the contents of the respective components in the regular structure catalyst S-5 are shown in Table 1. XRD analysis of the regular structure catalyst S-5 was similar to that of example 1. In XRD spectrogram of regular structure catalyst S-5 treated by carbon-containing atmosphere, diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-5 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Example 6
A regular structure catalyst S-6 was obtained in the same manner as in example 1 except that iron nitrate was used in an amount of 5g and cobalt nitrate was used in an amount of 15g, based on the metal oxide.
The results of measuring the contents of the respective components in the regular structure catalyst S-6 are shown in Table 1. XRD analysis of the regular structure catalyst S-6 showed a similarity to that of example 1. In XRD spectrogram of regular structure catalyst S-6 treated in carbon-containing atmosphere, there are not only MgO diffraction peak at about 43.0 deg. but also Al at about 45.0 deg2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-6 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-6 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Example 7
A regular structure catalyst S-7 was obtained in the same manner as in example 1 except that the amount of iron nitrate was 15g and the amount of cobalt nitrate was 5g, in terms of metal oxide.
The results of measuring the contents of the respective components in the regular structure catalyst S-7 are shown in Table 1. XRD analysis of the regular structure catalyst S-7 showed a similarity to that of example 1. In XRD spectrogram of regular structure catalyst S-7 treated in carbon-containing atmosphere, there are not only MgO diffraction peak at about 43.0 degrees, but also Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-7 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-7 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Example 8
The procedure of example 1 was followed except that the CO/N concentration of 10 vol% was replaced with an ethane/nitrogen mixed gas having an ethane concentration of 10 vol%2Mixing the gases to obtain the catalyst S-8 with a regular structure.
The results of measuring the contents of the respective components in the regular structure catalyst S-8 are shown in Table 1. XRD analysis of the regular structure catalyst S-8 was similar to that of example 1. In XRD spectrogram of regular structure catalyst S-8 treated in carbon-containing atmosphere, there are not only MgO diffraction peak at about 43.0 degrees, but also Al at about 45.0 degrees2O3、Co2AlO4And MgAl2O4And the diffraction peaks at about 43.0 degrees and about 45.0 degrees are obviously strengthened and shifted to the left, and due to the fact that the catalyst S-8 with the regular structure is treated by the carbon-containing atmosphere, the diffraction peaks appear at 42.6 degrees and 44.9 degrees of 2 theta, and the diffraction peaks at 42.6 degrees and 44.9 degrees of 2 theta are FeC (Fe)3C and Fe7C3) The diffraction peak of (1). In addition, the regular structure catalyst S-8 showed a diffraction peak at 44.2 ℃ and a diffraction peak at 44.2 ℃ 2. theta. was a diffraction peak of elemental cobalt, as compared with the regular structure catalyst S-4.
Comparative example 1
Regular structure catalyst D-1 was obtained by following the procedure of example 1 except that the cobalt nitrate was replaced with the same mass of iron nitrate based on the metal oxide.
The results of measuring the contents of the respective components in the regular structure catalyst D-1 are shown in Table 1.
Comparative example 2
Regular structure catalyst D-2 was obtained by following the procedure of example 1 except that the iron nitrate was replaced with the same mass of cobalt nitrate based on the metal oxide.
The results of measuring the contents of the respective components in the regular structure catalyst D-2 are shown in Table 1.
Comparative example 3
Catalyst precursors were prepared as described in reference to US6800586 and structured catalysts were prepared as described in reference to CN 1199733C. Specifically, 34.4 g of dried gamma-alumina microsphere carrier is taken, alumina microspheres are impregnated by a solution prepared from 10.09g of cerium nitrate, 2.13g of lanthanum nitrate, 2.7g of copper nitrate and 18mL of water, and after impregnation, the catalyst precursor is obtained after drying at 120 ℃ and roasting at 600 ℃ for 1 hour. 10g of catalyst precursor and 30g of alumina sol (with a solid content of 21.5%) are mixed and then coated on a cordierite-coated honeycomb carrier (with a carrier pore density of 400 pores per square inch, a cross-sectional open porosity of 70% and a square pore shape), and the catalyst D-3 with a regular structure is obtained by drying (100 ℃, 4 hours) and calcining (400 ℃, 2 hours), wherein the content of an active component coating is 25 wt% based on the total weight of the catalyst with a regular structure.
TABLE 1
Figure BDA0001914496560000231
Note: the content of the first metal element and the second metal element is calculated by oxide, and the unit is weight percent.
Test example 1
The experimental example is used for reducing the NOx emission in the incomplete regeneration smoke under the aerobic condition of the catalysts provided by the example and the comparative example. Specifically, the regular structure catalyst is aged for 12 hours at 800 ℃ under the atmosphere of 100% water vapor, and then the evaluation of the incompletely regenerated flue gas of the simulated catalytic cracking is carried out.
The evaluation of the incompletely regenerated flue gas is carried out on a fixed bed simulated flue gas NOx reduction device, the catalyst with a regular structure is filled in a catalyst bed layer, the filling amount of the catalyst with the regular structure is 10g, the reaction temperature is 700 ℃, and the volume flow of the raw material gas is 1500mL/min (under the standard condition). The feed gas contained 3.7 vol.% CO, 0.5 vol.% oxygen, 800ppm NH3The balance being N2. Analyzing the gas product by an on-line infrared analyzer to obtain reacted NH3NOx and CO concentrations, and the results are shown in table 2.
TABLE 2
Numbering NOx concentration, ppm NH3Concentration, ppm CO concentration, vol%
Example 1 S-1 79 113 2.88
Comparative example 1 D-1 220 211 2.86
Comparative example 2 D-2 210 210 2.89
Comparative example 3 D-3 159 342 3.15
Example 2 S-2 80 117 2.87
Example 3 S-3 65 100 2.81
Example 4 S-4 85 119 2.82
Example 5 S-5 86 121 2.89
Example 6 S-6 89 115 2.89
Example 7 S-7 87 119 2.87
Example 8 S-8 81 111 2.87
As can be seen from the data in Table 2, the use of the structured catalyst provided by the present invention in the incomplete regeneration process of the catalytic cracking process under the aerobic condition has better NH reduction than the catalyst provided by the comparative example3And NOx emission performance, and the aged regular structure catalyst is used in the evaluation process, and NH is removed from the aged regular structure catalyst3And the NOx activity is still higher, so that the regular structure catalyst provided by the invention has better hydrothermal stability.
In the invention, test example 1 is adopted to simulate the effect of contact between the incompletely regenerated flue gas and the regular structure catalyst in the CO incinerator in the treatment process of the incompletely regenerated flue gas, and because air supplement exists in the CO incinerator and oxygen exists in the contact process, the flue gas provided by test example 1 of the invention has a certain amount of oxygen, and the effect of test example 1 of the invention can show that when the regular structure catalyst provided by the invention is used for being contacted with the incompletely regenerated flue gas in the CO incinerator, the regular structure catalyst provided by the invention has better NH (NH) resistance than the prior art3Catalytic conversion activity of reduced nitrides.
Test example 2
The experimental example is used for reducing the effect of NOx emission in incomplete regeneration smoke under the condition of oxygen deficiency on the catalysts provided by the example and the comparative example. Specifically, the regular structure catalyst is aged for 12 hours at 800 ℃ under the atmosphere of 100% water vapor, and then the evaluation of the incompletely regenerated flue gas of the simulated catalytic cracking is carried out.
The evaluation of the incompletely regenerated flue gas is carried out on a fixed bed simulated flue gas NOx reduction device, the catalyst with a regular structure is filled in a catalyst bed layer, the filling amount of the catalyst with the regular structure is 10g, the reaction temperature is 650 ℃, and the volume flow of the raw material gas is 1500mL/min (under the standard condition). The feed gas contained 3.7 vol.% CO, 800ppm NH3The balance being N2. Analyzing the gas product by an on-line infrared analyzer to obtain reacted NH3NOx and CO concentrations, and the results are shown in table 3.
TABLE 3
Numbering NOx concentration, ppm NH3Concentration, ppm CO concentration, vol%
Example 1 S-1 0 197 3.7
Comparative example 1 D-1 0 412 3.7
Comparative example 2 D-2 0 409 3.7
Comparative example 3 D-3 0 523 3.7
Example 2 S-2 0 191 3.7
Example 3 S-3 0 163 3.7
Example 4 S-4 0 219 3.7
Example 5 S-5 0 221 3.7
Example 6 S-6 0 215 3.7
Example 7 S-7 0 219 3.7
Example 8 S-8 0 199 3.7
As can be seen from the data in Table 3, the use of the structured catalyst provided by the invention in the incomplete regeneration process of the catalytic cracking process under the oxygen-free condition has better NH reduction than the catalyst provided by the comparative example3The emission performance is evaluated by using an aged regular structure catalyst, and NH is removed from the aged regular structure catalyst3The activity is still higher, so the regular structure catalyst provided by the invention has better hydrothermal stability.
The invention adopts the test example 2 to simulate the effect of the contact of the incompletely regenerated flue gas and the catalyst with the regular structure in the flue gas channel arranged in front of the CO incinerator in the treatment process of the incompletely regenerated flue gas, and because the flue gas channel arranged in front of the CO incinerator is in an oxygen-deficient state, a plurality of flue gas channels are in the contact processThe flue gas provided by the test example 2 of the invention does not contain oxygen, and the effect of the test example 2 of the invention can show that when the regular structure catalyst provided by the invention is used for contacting with the incompletely regenerated flue gas in a flue gas channel arranged in front of a CO incinerator, the regular structure catalyst provided by the invention has better NH (hydrogen) resistance than the prior art3Catalytic conversion activity of reduced nitrides.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (16)

1. A structured catalyst for reducing NOx emissions in flue gases, the catalyst comprising: the catalyst comprises a regular structure carrier and an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier, wherein the content of the active component coating is 10-50 wt% based on the total weight of the catalyst; the active component coating contains an active metal component and a substrate, the active metal component comprises a first metal element and a second metal element, the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the weight ratio of Fe to Co is 1: (0.1-10), and the second metal element is at least one selected from group IA and/or IIA metal elements.
2. Structured catalyst according to claim 1, wherein the active component coating is present in an amount of 15 to 40 wt. -%, preferably 20 to 35 wt. -%, based on the total weight of the catalyst.
3. The structured catalyst of claim 1, wherein,
the content of the substrate is 50-90 wt% based on the total weight of the active component coating, the content of the first metal element is 3-30 wt% and the content of the second metal element is 1-20 wt% calculated by oxide;
preferably, the content of the substrate is 60-90 wt%, the content of the first metal element is 5-25 wt% and the content of the second metal element is 2-15 wt% calculated by oxide, based on the total weight of the active component coating;
further preferably, the content of the substrate is 72 to 85 wt%, the content of the first metal element is 10 to 16 wt%, and the content of the second metal element is 5 to 12 wt%, calculated as an oxide, based on the total weight of the active component coating.
4. A structured catalyst according to any of claims 1-3, wherein the weight ratio Fe to Co, calculated as oxides, is 1: (0.3-3), preferably 1: (0.4-2).
5. A structured catalyst according to any of claims 1-4, wherein the Fe in the catalyst is at least partly present in the form of iron carbide; at least part of Co in the catalyst exists in the form of elementary cobalt;
preferably, the catalyst has an XRD pattern with diffraction peaks at 42.6 °, 44.2 ° and 44.9 ° 2 θ.
6. Structured catalyst according to any of claims 1-5, wherein the second metal element is selected from at least one of Na, K, Mg and Ca, preferably K and/or Mg, most preferably Mg.
7. Structured catalyst according to any of claims 1-6, wherein the matrix is selected from at least one of alumina, silica-alumina, zeolite, spinel, kaolin, diatomaceous earth, perlite and perovskite, preferably from at least one of alumina, spinel and perovskite, further preferably alumina;
preferably, the regular structure carrier is selected from a monolithic carrier with a parallel pore channel structure with two open ends;
preferably, the pore density of the section of the regular structure carrier is 20-900 pores/square inch, and the aperture ratio is 20-80%;
preferably, the carrier of the regular structure is at least one selected from the group consisting of a cordierite honeycomb carrier, a mullite honeycomb carrier, a diamond honeycomb carrier, a corundum honeycomb carrier, a zircon corundum honeycomb carrier, a quartz honeycomb carrier, a nepheline honeycomb carrier, a feldspar honeycomb carrier, an alumina honeycomb carrier and a metal alloy honeycomb carrier.
8. A method of preparing a structured catalyst for reducing NOx emissions in flue gases, the method comprising:
(1) mixing and pulping a substrate source, a first metal element precursor, a second metal element precursor and water to obtain active component coating slurry;
(2) coating a regular structure carrier with the active component coating slurry, and drying and roasting to obtain an active component coating distributed on the inner surface and/or the outer surface of the regular structure carrier;
the first metal element is selected from non-noble metal elements in a VIII group, the first metal element comprises Fe and Co, and the second metal element is selected from at least one of metal elements in IA and/or IIA groups;
in the first metal element precursor, the use amounts of the precursor of Fe and the precursor of Co are such that, in the prepared catalyst, the weight ratio of Fe to Co is 1: (0.1-10).
9. The method of claim 8, wherein the firing conditions include: the reaction is carried out in a carbon-containing atmosphere at the temperature of 400-1000 ℃, preferably 450-650 ℃ and the time of 0.1-10h, preferably 1-3 h;
preferably, the carbon-containing atmosphere is provided by a gas containing carbon-containing elements selected from at least one of CO, methane and ethane, preferably CO;
preferably, the volume concentration of CO in the carbon-containing atmosphere is between 1 and 20%, preferably between 4 and 10%.
10. The method according to claim 8 or 9, wherein the coating is such that the catalyst is obtained in a content of the active component coating of 10-50 wt. -%, preferably 15-40 wt. -%, further preferably 20-35 wt. -%, based on the total amount of the catalyst;
preferably, the matrix source, the first metal element precursor and the second metal element precursor are used in an amount such that the catalyst is obtained in which the matrix content is 50 to 90 wt%, the first metal element content is 3 to 30 wt% and the second metal element content is 1 to 20 wt%, in terms of oxide, based on the total weight of the active component coating layer; preferably, the content of the substrate is 60-90 wt%, the content of the first metal element is 5-25 wt% and the content of the second metal element is 2-15 wt% calculated by oxide, based on the total weight of the active component coating; further preferably, the content of the substrate is 72 to 85 wt%, the content of the first metal element is 10 to 16 wt%, and the content of the second metal element is 5 to 12 wt%, calculated as an oxide, based on the total weight of the active component coating.
11. A process according to any one of claims 8 to 10, wherein the Fe and Co precursors are used in amounts such that the resulting catalyst has a weight ratio of Fe to Co, calculated as oxides, of 1: (0.3-3), preferably 1: (0.4-2).
12. The method according to any one of claims 8-11, wherein the second metal element is selected from at least one of Na, K, Mg and Ca, preferably K and/or Mg, most preferably Mg;
the first metal element precursor and the second metal element precursor are respectively selected from water-soluble salts of a first metal element and a second metal element.
13. The method of any one of claims 8-12, wherein the substrate source is a substance that is convertible to a substrate under the conditions of the firing of step (2);
the matrix is selected from at least one of alumina, silica-alumina, zeolite, spinel, kaolin, diatomite, perlite and perovskite, preferably at least one of alumina, spinel and perovskite, and is further preferably alumina;
preferably, the regular structure carrier is selected from a monolithic carrier with a parallel pore channel structure with two open ends;
preferably, the pore density of the section of the regular structure carrier is 20-900 pores/square inch, and the aperture ratio is 20-80%;
preferably, the carrier of the regular structure is at least one selected from the group consisting of a cordierite honeycomb carrier, a mullite honeycomb carrier, a diamond honeycomb carrier, a corundum honeycomb carrier, a zircon corundum honeycomb carrier, a quartz honeycomb carrier, a nepheline honeycomb carrier, a feldspar honeycomb carrier, an alumina honeycomb carrier and a metal alloy honeycomb carrier.
14. Structured catalyst for reducing NOx emissions in flue gases, obtainable by a process according to any one of claims 8 to 13.
15. Use of a structured catalyst according to any one of claims 1 to 7 and 14 for reducing NOx emissions in flue gases in the treatment of catalytic cracking incompletely regenerated flue gases.
16. A method for treating incomplete regeneration flue gas comprises the following steps: contacting incomplete regeneration flue gas with a catalyst, wherein the catalyst is the structured catalyst for reducing NOx emission in incomplete regeneration flue gas in any one of claims 1 to 7 and 14;
preferably, the contacting is performed in a flue gas channel provided in front of the CO incinerator and/or the CO incinerator, further preferably in a flue gas channel provided in front of the CO incinerator;
preference is given toThe contacting conditions include: the temperature is 600-1000 ℃, the reaction pressure is 0-0.5MPa and the mass space velocity of the flue gas is 10-1000h based on gauge pressure-1
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