CN101351259A - Lower temperature CO promoters for FCC with low NOx - Google Patents

Abstract

A carbon monoxide oxidation promoter for use in an FCC regenerator comprises a mixture of base metal oxides, which are present in an amount so as to have a CO oxidation activity substantially less than a precious metal catalyst and which consequently reduces the amount of NOx contained in the regenerator flue gas. Typically, the carbon monoxide oxidation promoter will comprise a mixture of base metal oxides which are present on a support in amounts of less than 5 wt. % of the catalyst.

Description

The low temperature CO promoter that is used for FCC with low NOx

The cross reference of related application

The application requires the provisional application U.S.60/742 of submission on December 1st, 2005,213 priority.

Invention field

The present invention relates to be used for CO is changed into CO ₂Make the new catalyst composition of the NOx minimum emissions of part and the FCC regenerated device of completing combustion simultaneously

Background of invention

A main industrial problem relates to and is used to reduce air pollutants, for example from the exploitation of the effective ways of the concentration of carbon monoxide, oxysulfide and nitrogen oxide in the waste gas stream of the processing of the fuel of sulfur-bearing, carbon and nitrogen and burning.Being emitted under oxysulfide, carbon monoxide and the nitrous oxides concentration that these waste gas stream is often run in routine operation in atmosphere do not expected aspect the environment.In the catalytic cracking of the hydrocarbon of sulfur-bearing and nitrogen, be a typical process example that can produce the waste gas stream of the carbon monoxide, oxysulfide and the nitrogen oxide that contain relative high-load by the regeneration of the Cracking catalyst of deposits of coke inactivation.

The catalytic cracking of heavier petroleum fraction is one of main refining operation used in crude oil being changed into useful products (fuel that uses as internal combustion engine).In fluid catalytic cracking (FCC) technology, high-molecular-weight hydrocarbons liquid and steam are contacted in fluidized-bed reactor or in elongated carrier pipe reactor with the subdivided solids catalyst particle of heat, and keep fluidisation or dispersity to reach being enough to realizing being cracked into the time of the required cracking degree of the sort of lower molecular weight hydro carbons that exists usually in engine gasoline and the distillate fuel at elevated temperatures.

In the catalytic cracking of hydro carbons, some nonvolatile carbonaceous materials or coke laydown are on catalyst particle.Coke comprises highly condensed aromatic hydrocarbons.When this hydrocarbon feed contained organic sulfur and nitrogen compound, this coke also contained sulphur and nitrogen.Because coke build-up is on Cracking catalyst, the cracking activity of catalyst and this catalyst are used to produce the selectivity reduction of gasoline blending stock.From reaction zone, discharge continuously catalyst because of the basic inactivation of coke laydown.This decaying catalyst is sent to stripping zone, removes the volatility deposit at this at elevated temperatures with inert gas.Then by in the regeneration technology that is fit to, removing deposits of coke substantially, with the basic reactivation of catalyst particle to its initial ability.Send the catalyst of regeneration back to reaction zone continuously to repeat this circulation then.

By using oxygen-containing gas, for example the deposits of coke of air burning catalyst surface realizes the regeneration of catalyst.The burning of these deposits of coke can be regarded C as with simplified way _nH _nOxidation.The product of this type of burning is water, carbon monoxide and carbon dioxide.

The waste gas stream of this combustion process is known as flue gas.High residual concentration from carbon monoxide in the flue gas of regenerator has constituted problem at the very start from catalytic cracking process.The development of FCC causes using in the FCC regenerator more and more higher temperature to realize required low carbon content in the catalyst of regeneration.Usually, regenerator of today moves under about 1100 to 1400 temperature.When not using the CO oxidation accelerator, the CO of flue gas ₂/ CO ratio may be 1-3.The oxidation of carbon monoxide is strong heat release, and can cause so-called carbon monoxide " after-burning ", and this may be in rare catalyst phase (dilute-phase zone), take place in cyclone separator or in flue gas line.After-burning causes severe impairment to shop equipment.On the other hand, be discharged in the flue gas of atmosphere unburned carbon monoxide and represent the loss of fuel value, and aspect ecological, do not expect.

The technological advantage that the more complete oxidation that can be discharged into carbon monoxide quantitative limitation in the atmosphere and carbon monoxide is brought has inspired many schemes to realize whole burnings (complete combustion) of carbon monoxide in the regenerator---be also referred to as " completing combustion (full burn) ".

Suggestion is used in the method that obtains carbon monoxide completing combustion in the FCC regeneration and comprises: (1) increases the amount of the oxygen of introducing regenerator with respect to standard regeneration; Or the average operation temperature in (2) raising regenerator, or (3) comprise that in Cracking catalyst various carbon monoxide oxidation accelerators are to promote CO burning.For carbon monoxide after-burning problem, multiple solution has also been proposed, for example add external combustible or make water or heat absorbing solid to absorb the combustion heat of carbon monoxide.

Comprise with the instantiation of the applied processing of regeneration of full-burn mode operation and to add CO combustion improver metal to catalyst or in regenerator.In the regenerator of FCC apparatus, use the oxidation of precious metal catalyst carbon monoxide to obtain the wide range of commercial approval.In U.S. Patent No. 4,171, enumerated the part history of this section development in 286 and No.4,222,856.At the commitment of this development, with noble metal loading on the particle of Cracking catalyst.Present way normally can fluidized bed form be supplied promoter with the solid that contains noble metal, and this type of particle separates physically with the Cracking catalyst particle.Noble metal or its are compound loaded on the particle of suitable carriers material, and this promoter particle separates with the Cracking catalyst particle usually and introduces in the regenerator.In cracking/stripping/regeneration cycle process, the promoter particle is not removed from system as fines, but circulates altogether with the Cracking catalyst particle.

The commercial promoter product that is used in the FCC apparatus comprises the carrier material through calcining, spray-dired kaolin porous microsphere with a small amount of (for example 100 to 1500ppm) platinum dipping.The promoter of most of commercial uses is by obtaining on the microballoon that the platinum source is immersed in high-purity Woelm Alumina (normally transition alumina).Select platinum as if to reflect preferential selection to this metal as the noble metal in the various commercial products, this with think that platinum is that the prior art disclosure of the most effective VIII family metal is consistent for the promotion of the carbon monoxide oxidation in the FCC regenerator.

Judge the CO efficiency of combustion of promoter by the ability of the close temperature difference Δ T between mutually of control (heat) dilute phase, cyclone separator or flue gas line and (colder).Most of FCC apparatus use Pt CO combustion improvers, but use mainly the non-Pt promoter based on Pd recently more and more widely.

U.S. Patent No. 4,608,357 have instructed when on the silica-alumina that palladium is loaded on particular form (being the mullite of the leaching) particle, and palladium is promoting carbon monoxide to effective unusually aspect the oxidation of carbon dioxide under as the common condition in the regenerator of FCC apparatus.Palladium can be unique metal component with catalytic activity in this promoter, or its can with other metal mixed as platinum.

At EPA agree court verdict (consent decrees) wait a large amount of technology of carrying out and obviously all business exercises all concentrate on and be used to develop the noble metal that hangs down NOx CO promoter.So in practice, noble metal is the material that uses in the industry.Yet, be known by the CO oxidation of non-precious metal catalyst, they see patent documentation to the purposes of FCC regeneration.Usually the purpose of these work is to make the CO activity of conversion maximum of per unit weight reactive metal and/or additive, to compete mutually with the agent of high activity noble metal promoted better.In history, selecting the major impetus of CO promoter is its convenience and cost for refinery, but NO _xDischarging has become even more important recently.

When using as the combustion improver of platinum reduces the CO discharging, this minimizing that CO discharges is accompanied by not desired effects usually---the increase of nitrogen oxide in the regenerator flue gas (NOx).The use of having reported the CO promoter of prior art can cause the rapid increase (for example＞300%) of NOx.In catalyst regenerator, be difficult to completing combustion coke and CO under the situation of NOx content in not increasing regenerator flue gas.Because with discharged nitrous oxides not environmental protection and be subjected to strict control in the atmosphere, the consequence of using these promoter is that a kind of emission of not expecting is replaced by the another kind of emission of not expecting.The concern of response environment aspect in order to seek the method that reduces the NOx discharging in control after-burning and flue gas CO concentration, has been paid many effort.

Used several different methods to reduce the formation of NOx or after it forms, handled.Most typically be, used additive as the part of FCC catalyst particle or as with the independent particle of FCC catalyst mix.

Developed at control NO _xPlay the multiple additives of CO oxidation facilitation in the time of discharging.

U.S. Patent No. 4,350,614,4,072,600 and 4,088,568 disclose rare earth have been added in the Pt base CO promoter.An example is the 4%REO that shows certain advantage.It does not instruct REO to reducing any effect from the NOx discharging of FCC.

U.S. Patent No. 4,199,435 have instructed the combustion improver that is selected from Pt, Pd, Ir, Os, Ru, Rh, Re and copper on inorganic carrier.

U.S. Patent No. 4,290,878 have instructed and have compared the Pt-Ir and the Pt-Rh bimetallic promoter of having reduced NOx with conventional Pt promoter.

U.S. Patent No. 4,300,997 have instructed the purposes of Pd-Ru promoter in the CO oxidation, and this promoter can not cause excessive NOx to generate.

U.S. Patent No. 4,544,645 have described the bimetallic of Pd with each other metal of VIII family except that Ru.

U.S. Patent No. 6,165,933 and 6,358,881 have described the composition that comprises following component, this component contain (i) acidic oxide support, (ii) alkali metal and/or alkaline-earth metal or its mixture, (iii) have the transition metal oxide of oxygen storage capacity and a (iv) palladium; Thereby in FCC technology, promote the CO burning and make NO simultaneously _xGeneration minimum.

U.S. Patent No. 6,117, the CO promoter that 813 instructions are made of VIII group 4 transition metal oxide, IIIB group 4 transition metal oxide and IIA family metal oxide.

Opposite with complete CO burning, the FCC catalyst regenerator can move under the imperfect combustion pattern, and this is commonly referred to " partial combustion " device.Incomplete CO burning stays a large amount of relatively coke at the regenerated catalyst that is sent to the FCC reaction zone from the FCC renewing zone.The relative amount of CO is higher relatively in regenerator flue gas, promptly about 1 to 10 volume %.The key feature of partial combustion model F CC is, owing to suppressed the CO combustion reaction of heat release, has reduced the fuel factor of the coke burning of every weight coke.This can realize higher oily production capacity and lower regenerator temperature, and keeps these benefits to be absolutely necessary for the economy of FCC technology.Under partial-burn operation, in regenerator flue gas, may not observe NOx, but in flue gas, have the ammonia and the HCN of a great deal of usually.

Although prior art concentrates on the influence that additive generates NOx in the completing combustion operation, when much lower discharge standard occurring, these known additives are just becoming and more and more are being not suitable for.In addition, do not prove that also these additives are effective in the partial combustion operation.The partial combustion operation makes CO to CO ₂Conversion minimize, but it is characterized in that in flue gas, existing HCN and NH as mentioned above ₃Partially combusted chemism shows HCN and NH ₃Be N ₂With the intermediate product in the NOx generative process.But no matter be with the mid portion burning or with the operation of completing combustion form, CO promoter is all used in most of FCC operations.The problem of this area is, uses known CO promoter simultaneously with HCN and NH ₃Change into NOx, increased the discharging of NOx in the partial combustion operation.

Nowadays the great majority from principal manufacturer of Shi Yonging (even not being whole) CO promoter is based on noble metal.Pd is preferably to reduce NO recently _xSelectivity.Research to the noble metal promoted agent is still continuing (6,358,881; Or US 2004/0074809 A1).Although not general in practice, generally be used for the CO oxidation and particularly in the base metal catalysts field at FCC, quite a large amount of prior aries arranged still.

Engine exhaust gas catalyst needs noble metal to have competitiveness on market.Still carrying out big quantity research managing substituting them, thereby reducing cost with base metal batching.People such as Voorhoeve (Science 177 354, on July 28th, 1972) expression, lanthanum cabalt glance and praseodymium cabalt glance with perovskite structure are the active catalysts that is used for the CO oxidation, and with CO, H ₂And H ₂Can be when O mixes with NO _xBe catalysed and reduced into N ₂(and N ₂O).They propose this catalyst and can be used for waste gas purification.

Whelan is at US 3,885, and proposing in 020 with Zr, Sn or Th and optional alkali-earth metal modified rare earth and transition metal perovskite catalyst is effective for big quantitative response, is included in those reactions in combustion product and the NOx related compound.Sets forth in detail the theory of perovskite, but do not have to disclose their application in FCC.U.S.3,897,367 provide the more useful argumentation of perovskite theory.The application of perovskite is at waste gas in this patent, particularly engine exhaust but not the cleaning of FCC.This material also contains noble metal.US 5,093, and 301 disclose the La-Sr-Fe-Cu-Mn perovskite of the one deck at least that is used for general burn application.Do not mention FCC.This catalyst also may comprise the layer of mixture of the same metal of oxide form, is spinel structure A now ₁B ₂O ₄Cu with the perovskite combination ₁Fe ₂O ₄And FeMn ₂O ₄Spinelle is a therefore known CO oxidation catalyst, but it is said that its hole size will make can not limit mass transfer.

At US 4,102, in 777, Wheelock discloses by at first preparing the carrier material of spinelle coating, flood then the perovskite precursor salt and 600-1000 °F down calcining prepare " high surface perovskite catalyst ".Use La, Fe, Mn and Cu but get rid of silicon as carrier or adulterant.At US 4,446, in 011, Wheelock discloses and used the burning of perovskite with auxiliary coke in FCC.Perovskite can be used as additive not load or load and uses, or it can be sneaked in the main FCC catalyst.Preferred material is barium zirconate or hafnium acid barium.The perovskite of proposition 0.1 weight % to 20 weight % in the FCC catalyst mixture.The purpose of this invention is to use perovskite to improve the coke burn rate, and an embodiment shows the CO that improves in regeneration ₂/ CO ratio, but NOx result is not disclosed, and in this patent, do not discuss NOx.

Gladrow is at US 4,208, described the Cracking catalyst that contains at least a transition metal that comprises 0.5-10 weight % perovskite under 3-20% zeolite, inorganic oxide gel and the wide region in 269, and the processing of relevant hydrocarbon.LaCoO ₃Be preferred perovskite, and the perovskite of 1.5-4% is preferred.The inventor finds that surprisingly CO is promoted to form CO effectively ₂, but in this patent not mentioned NO _x

Vasalos is at US 4,440, in 632 by with O ₂Join and reduce SOx discharging in the FCC dead catalyst stripper, compare its S in the combustion of coke slightly preferentially of C in the coke.Its detailed Description Of The Invention is partly described, and can choose wantonly in the method to add the SO of water-gas shift catalyst to promote that the S selective combustion produces in stripper ₂Be reduced into H ₂S leaves from the riser side.The definite character of this conversion catalyst metal it is said not crucial, can comprise 0.01-10 weight %, and it can be dispersed in the whole FCC catalyst or independently additive existence of conduct.Compare with many other catalyst, listed appropriate conversion catalyst is Fe ₂O ₃With CuO and composition thereof.Many carriers have been proposed.Carry out the regeneration of coke catalyst, but do not reported CO ₂/ CO, and in this patent not mentioned NO _x

People such as Dieckmann (US 5,364, and 517; 5,565,181) the FCC NOx reduction additive based on spinelle/perovskite structure that it is said the maintenance activity and tolerate sulphur is disclosed.This perovskite contains at least a transition metal, and preferred embodiment is that the load capacity in this additive itself is 1-40%, the Ln-Cu-Mn-Fe perovskite of preferred 10-30%.Example is about 15% or 25% carrying capacity.This additive also comprises IIA/IIIA family spinelle, for example MgAl ₂O ₄, and optional stabilizing agent, as copper.This patent proposes, and this additive can be used as independently microballoon use or is dispersed in the whole FCC catalyst.But, in this patent, be not given in the whole FCC catalyst dispersing additive or promote active preparation additive at NO with low carrying capacity and CO _xThe theory of the concrete application of aspect or advantage, explanation or preferred as a result.It is compatible with the CO oxidation accelerator that this additive also is considered to, and this CO oxidation accelerator can be considered to be meant the noble metal (being essentially capacity) that keeps being equal to or less than 1ppm.

Tang and Lin (US 5,242, and 881; CO oxidation activity and stable further improvement when 5,443,807) proposing in FCC regeneration, to use mullite as carrier.An embodiment shows with standard 500ppm Pt CO promoter and compares NO _xReduce simultaneously, but the main center of this patent be to realize with the equal or higher CO activity of conversion of typical Pt promoter to reduce cost.Use perovskite carrying capacity of 5-20% on the additive of mullite load realizes high activity and stability.Do not point out that this may be harmful in the NOx selectivity.

McCauley (US 6,117,813) attempts to solve identical activity and cost problem with mixed-metal oxides system (for example La-Sr-Co oxide) in the alumina support outside using mullite.Guidance be not provided aspect phase, component ratio or the carrying capacity, but the metal oxide of embodiment and claim suggestion 8-10 weight %.The main points of this patent be make can with as 500ppmPt/Al ₂O ₃And so on the high activity base metal CO promoter of noble metal promoted agent competition.

People such as Lin (US 6,596,249) disclose a kind of base metal promoter based on Cu-Al on alumina support and Ce-Al composite oxides.The promoter that the load generation of these two kinds of composite oxides is suitable with the 500ppm Pt on the aluminium oxide with high catalytic activity and stability.Pilot plant test shows that obviously 50% NOx reduces.

People such as Yoo (US 4,790,982) propose a kind of and third and fourth metal (is used for SO _xOxidation and reduction) (be used for SO in conjunction with containing metal spinelle as the SOx additive among the FCC ₃Absorb).This patent has been enumerated many mixed-metal oxides with spinel structure, comprises CuFe ₂O ₄, MnFe ₂O ₄, NiFe ₂O ₄And Fe ^IIFe ^III ₂O ₄These spinel oxides use with high carrying capacity, and serve as carrier usually.Most preferred form (the Ce/V/MgAl that it is said this technology ₂O ₄) NOx is reduced, but the purposes of these spinelles as low NOx CO oxidation accelerator is not discussed in these patents.

Therefore, the use of base metal CO oxidation accelerator (especially perovskite) is known in FCC.It is reported that some prescriptions show NOx really and optionally improve, and pass through the optimization of prescription and catalytic chemistry thereof, this is possible really, even they are in overheated operation down.In the known technology and unexposed following notion, promptly noble metal or base metal promoter may be subjected to diffusion-restricted and heat transfer limitations, and this is important for the NOx selectivity.Therefore, the prior art low activity base metal CO promoter that all can not obtain not to be subjected to heat transfer limitations and therefore under temperature more, work near the mean temperature of regenerator dense bed.The use of colder CO promoter microballoon is accompanied by the lower defective of intrinsic CO oxidation rate, but as unexpected benefit, the same colder operation of imagination has the NO of reduction _xSelectivity.

One object of the present invention is in the presence of SOx and steam, makes HCN and NH in completing combustion or mid portion burning FCC regenerator ₃(NOx precursor) is oxidized to side by side that the situation of NOx is minimized to be converted into CO with CO simultaneously ₂

One object of the present invention is to replace fully and eliminates in the FCC apparatus needs to noble metal CO promoter, thereby avoids their high NOx output.

One object of the present invention is to make in completing combustion or mid portion burning FCC regenerative process NOx in the dense bed and NOx precursor to N ₂Conversion maximization.

Summary of the invention

The invention describes the mixing base metal CO oxidation accelerator that is used for FCC, it makes HCN and NH ₃Simultaneous oxidation becomes the situation of NOx to minimize, and already present NOx is reduced into N ₂Example is the mixing base metal oxide that was known as water-gas shift or CO oxidation catalyst in the past and was known as the CO promoter among the FCC to a certain extent.The improvement of this paper is, preparation on carrier with low carrying capacity base metal CO promoter or mix in the FCC catalyst, thereby make the promoter activity of per unit weight additive be lower than the standard 500ppm Pt/Al that under the FCC condition, uses ₂O ₃About 10% of the activity of CO promoter.This low activity is considered to alleviate mass transfer and heat transfer limitations, and this allows microballoon more working under the colder temperature near average bed temperature according to inferring.The promoter of prior art has so high active so that they are in use obviously overheated, has improved the NOx selectivity under the situation of base metal promoter.But the Pt promoter made from low carrying capacity almost or does not fully show optionally improvement under colder operation, so SA noble metal promoted agent is not within the scope of the invention.

Have highly active base metal CO promoter and compare also not remarkable the improvement with the noble metal promoted agent NO _XSelectivity.But, surprisingly, have been found that if these base metal promoter prepare under low concentration equally, they under constant CO conversion ratio to NO _XSelectivity significantly reduce.Infer in theory, the optimization of the CO activity of conversion of per unit base metal in the past so success so that gained promoter because conduct heat and mass transfer limit also in use overheated, and thisly overheatedly make its selectivity variation and increase NO _XSurpassed 30 years because base metal CO oxidation catalyst is known, can conclude, this area is not obviously considered this restriction that caused by high activity as yet.

The accompanying drawing summary

Fig. 1 is that temperature is to NH ₃Mars-van Krevelen is oxidized to NO _XThe figure of influence of free energy, wherein key be the explanation metal oxidation before with afterwards oxidation state.

Fig. 2 utilizes λ scanning, gets around the CO that reaction directly enters the simulation regenerator reactor feed of analyzer ₂, CO and O ₂The figure of material, wherein charging transforms between rich fuel and poor fuel state.

Fig. 3 utilizes λ scanning, gets around the figure of nitrogen material that reaction directly enters the simulation regenerator reactor feed of analyzer, and wherein charging transforms between rich fuel and poor fuel state.

Fig. 4 is contrast noble metal catalyst and the poor fuel-side NO of base metal oxidation catalyst under high and low carrying capacity as described in example 4 above _XThe figure that forms.

Fig. 5 is to use as described in example 4 above the base metal oxide catalyst under various carrying capacity to remove NO _XThe figure of performance.

Fig. 6 represents to use as described in example 5 above not the catalyst that promotes and the nitrogen compound output found according to the catalyst of various promotions of the present invention and the bar chart of CO2/CO ratio.

Fig. 7 A, B and C show each catalyst NO separately in three λ circulations _XWith the formation of N2, wherein for each λ circulation and as described in example 5 above, charging transforms between rich fuel and poor fuel.

Fig. 8 is that expression is used various contrasts and oxidation accelerator of the present invention and as described in example 6 above at the total nitrogen compound output of λ scan operation integration and the bar chart of CO2/CO ratio.

Fig. 9 shows the CO2/CO curve that various oxidation accelerators are more as described in example 6 above found in the λ scanning process.

Figure 10 A, 10B and 10C are to use various oxidation accelerators and the N in the λ scanning process as described in example 6 above respectively ₂, NOx and NH ₃The figure of transient response.

Figure 11 is the figure that relatively has the poor fuel-side NOx generation of constant CO oxidation activity and various CO oxidation accelerators as described in example 7 above.

Figure 12 is the bar chart to the influence of nitrogen material that is illustrated under the various OTRs and finds when moving regenerator as described in example 8 above.

Figure 13 A-13D is the various simulation OTRs CO in three λ circulations down and as described in example 8 above that is illustrated in the regenerator ₂, CO, O ₂, N ₂And NO _XThe figure of transient state content.

Figure 14 is that contrast noble metal CO oxidation catalyst and two kinds of CO oxidation catalysts of the present invention are with respect to CO ₂/ CO and total NO as described in example 9 above _XThe figure of output.

Figure 15 is the schematic design that the regenerator of particle flux wherein is shown.

Figure 16 is the schematic design that is used to move the testing arrangement of λ sweep test as be shown in the examples.

Invention is described

Do not wish to be limited by any theory, but propose the NH based on Mars-van Krevelen selective oxidation mechanism now₃The approximate model of oxidation. This mechanisms known supposition body Lattice Oxygen is the oxidant source in these reactions. We infer in theory, can be at NH₃And metal oxide draws similitude between the stoichiometric reaction under 1300 °F and selective catalytic oxidation. If generate N₂The Gibbs free energy of stoichiometric reaction for negative, then generate N₂Catalytic reaction can suppose with rational speed and carry out. If generate NO_XThe Gibbs free energy of stoichiometric reaction also for negative, then generate NO_XCatalytic reaction also may carry out, potential increase is to NO_XSelective. We have estimated the Gibbs free energy as temperature funtion, find that platinum oxide can make NH by stoichiometric reaction under all rational temperature₃Generate NO_X On the other hand, the free energy of base metal has less negative value, near 0, or or even positive number, this is hinting NO_XUnlikely generate by catalytic reaction by supposition. This is shown among Fig. 1. From Fig. 1, also know and find out along with temperature raises, generate NO by stoichiometric reaction_XPossibility improve. Although only cautiously this is extrapolated to catalysis, because calculating occurs unusually really, general trend can be used as guidance, and its hint is along with temperature rising, NH₃Be oxidized to NO_XSelectively may reduce. Therefore, we assert, and are unexpected and surprisingly so far, and the activity that only weakens the CO promoter made from base metal advantageously reduces NO_XSelective, simultaneously can the agent of appreciable impact noble metal promoted.

On current material, with regard to NH₃Become N with the HCN selective oxidation₂, obtain significantly improved selective: to NO_XPoor fuel-side selectivity ratios generally be used for the low 60-70% of noble metal of regenerator CO oxidation. The per unit weight CO activity of reactive metal is in fact much lower than noble metal. But, have been found that surprising result, namely noble metal so active so that they in the promoter hole, seem to conduct heat when freshly tested under regenerator conditions limited limited with mass transfer. Usually, the noble metal promoted agent contains Pt or the Pd of 300-500ppm.

Used base metal material comprises the transition metal of the periodic table of elements except that noble metal in the mixed oxide promoter of the present invention.Some transition metal may be because its toxicity and not preferred.Available mixing base metal material comprises following Fe ₂Cu1 and Mn ₂The Cu1 based formulas, in the clean reducing gas environment of rich fuel and under the clean oxidizing condition at poor fuel all to NH ₃, HCN and NO _XTo N ₂Conversion have especially high activity and selectivity.Current material is included in the noble metal that contains on the Ce carrier, has much higher to NO on poor fuel-side _XConversion ratio and output.This is quite meaningful, mainly comprises (if not including only) poor fuel condition because account on market than great share and as the main user's of CO promoter completing combustion regenerator.Poor fuel-side NOx is difficult to reduce in the past.Surprisingly, the N of material of the present invention ₂In fact selectivity becomes more and more poorer fuel along with condition and improves.

In brief, disclose the base metal CO oxidation accelerator that is used for FCC, it makes HCN and NH ₃Simultaneous oxidation becomes the situation of NOx to minimize, and already present NOx is reduced into N ₂This mixing base metal oxide was known as Water gas shift/WGS or CO oxidation catalyst (also being known as the CO promoter among the FCC to a certain extent) in the past.Improvement among the present invention is with low mixed-metal oxides carrying capacity and active preparation.This mixed-metal oxides loads on the carrier or mixes in the FCC catalyst, so that the CO oxidation activity of per unit weight additive is less than the standard 500ppmPt/Al that uses under the FCC condition ₂O ₃CO promoter activity about 10% is preferably less than 1%.The CO oxidation activity of promoter additive of the present invention should be standard 500ppmPt/Al ₂O ₃At least 0.2% of CO oxidation accelerator activity, preferably at least 0.5%.Although other explanation is also possible, be considered to alleviate mass transfer and heat transfer limitations than low activity, and this allows microballoon more working under the colder temperature near average bed temperature according to inferring.It is in use obviously overheated that the promoter of prior art has so high active so that this class promoter, improved the selectivity to NOx under the situation of base metal promoter.But the Pt promoter made from low carrying capacity almost or does not fully show the optionally reduction to NOx under colder operation, so SA noble metal promoted agent is not within the scope of the invention.

In preferred embodiments, with base metal promoter of the present invention and high activity Cracking catalyst, the particularly common U.S. Patent No. of transferring the possession of 6,656, the catalyst premixing described in 347 and.Preferably, this mixture is as additive, thereby exceedingly do not weaken the cracking activity of the total materials of FCC catalyst (inventory), and any FCC apparatus all can benefit from this technology, and regardless of the source of supply of main FCC catalyst.

Typical CO oxidation accelerator prescription of the present invention contains and is less than 5 weight %, is less than about 3 weight % usually, and the further base metal of the oxide form of about at the most 1 or 2 weight % carrying capacity for example.The limiting examples of mixing base metal oxide is included in the Fe on the alumina support ₂Cu ₁O ₄Or Mn ₂Cu ₂O ₄, may contain promoter such as Ni, La, alkaline-earth metal, rare earth.Other metal oxide carrier can use and be as known in the art.The limiting examples that in the following example, provides available base metal oxide to fill a prescription.

Generally speaking, suggestion can be used and not contain noble metal, and in the past known be more than 500 ℃, water-gas shift " WGS " or CO oxidation catalyst or promoter under the preferred temperature more than 600 ℃, and the activity of its significant quantity is not to come from Cu ^o, Cu ₂Any good catalyst of O or CuO.Importantly, when making FCC CO promoter, the CO oxidation activity that effective catalyst records at least under the FCC of 1100 of temperature regenerator conditions should be than 500ppm Pt/Al ₂O ₃Low less than about 10 times, preferably less than 100 times, generate thereby reduce NOx.The present invention does not relate to any specific ratios or combined any particular combinations with the metal oxide that forms WGS or CO oxidation catalyst.In addition, the carrier (the oxide deposition is mixed thereon or with it) and the method for these catalyst of manufacturing are all inessential to the present invention.The low NO of the catalyst that is proposed conduct in FCC _XThe use of promoter looks like new, as long as promoter is enough low to the activity of CO oxidation.

As mentioning separately, paid close attention in a large number and used the hybrid metal perovskite as oxidation catalyst in the prior art part.Before this technology is traced back to 30 years.Determine it is LaCoO in early days especially ₃Henceforth, it is effective containing that the combination of La, Co, Cu, Fe, Mn, Ni, Sr, Ca and other element and element-specific is suggested with other material that produces structural vacancy.Tang and Lin (U.S.5,242,881; 5,443,807) CO oxidation activity and stable further improvement when using mullite as the carrier in the FCC regeneration are proposed.But these patentees have ignored basic low activity and the low carrying capacity aspect of the present invention.

Some technology about perovskite have required to add noble metal in these catalyst.We think, for obtaining optimum, should get rid of noble metal.For the present invention, noble metal is meant Ru, Rh, Pd, Ag, Os, Ir and Pt.No matter base metal oxide catalyst of the present invention is perovskite or any other structure, all should be suitable for this eliminating.Certainly, under enough low carrying capacity, trace, for example less than 75ppm or less than 5ppm and even the noble metal of 1ppm may be unimportant.

Also get rid of the catalyst that its quite a large amount of activity derives from fine copper or its oxide.CuO on aluminium oxide or Cu/Al ₂O ₃Test be found in the catalyst regeneration process in poor fuel-side and produced NOx, and its Gibbs free energy allows CuO with NH ₃Make NOx.Copper still is the main pillar that prior art is used for the NOx additive.But, copper and some other oxide, particularly Fe and Mn, and generally the combination of the base metal oxide of other except that ceria it is found that quite favourable.This is surprising, and we can not predict this result.But, infer that according to the selective oxidation document intensity of the Cu-O-M key that exists in mixed copper Base Metal (M) oxide and the activity of oxygen atom are for N ₂Form more effective or be not suitable for NOx and form.According to this supposition, preferably copper and other oxide-metal combinations to be being formed on mixed-metal oxides stable under the regenerator conditions mutually, rather than form cupric oxide and the analog that is separated.At present and do not know which base metal is the most suitable and mix with Cu.The content of Cu oxide should be less than the 40 weight % that mix the base metal oxide batching.

The prescription that experimental development goes out comes from known water-gas shift catalyst.Because the oxidation of hydrogen is easy, we infer, reaction CO+H ₂O=CO ₂+ H ₂And H ₂+ O ₂=H ₂The summation of O is CO+O ₂=CO ₂, so water can become the co-catalyst that carries out the CO oxidation by the water-gas shift catalyst.It is active low NOx promoter that the high temperature shift catalysts that only contains base metal is inferred thereupon.K.Kochloefl is at " Handbook of Heterogeneous Catalysis " Ertl, G.Knozinger, and H., and Weitkamp, J., Eds. lists the Chrome-free batching based on Co-Mn, Cu-Mn, Fe-Mn that promotes with alkali in (1997).Because environment and health problem, chromium is not preferred ingredient.We have prepared this class catalyst and have found that they change into CO for CO under regenerator conditions ₂Normally active, but their specific activity noble metal is much lower.Opposite with prior art, nowadays this result is regarded as favourable.

Believe that now the WGS reaction on the high temperature Fe-Cr catalyst is by taking place with the similar OR mechanism of the Mars-van Krevelen mechanism of selective oxidation.We confirm that it is active that high temperature WGS catalyst transforms the CO in the regenerator, according to this confirmation, nowadays we can be used as the prior art of high-temperature water gas conversion catalyst the guidance that is used for high activity (per unit mixed-metal oxides) the CO promoter of FCC about preparation.So scope of the present invention comprises the instruction of high temperature WGS (" HT the WGS ") technology that is used for FCC promoter, its improvement is its active restriction is not higher than in regenerator conditions, for example at least 1100 following every weight activity about 10% of 500ppm Pt reference standard sample (USP-500) additives of test preferably are not higher than about 1%.

The NOx selectivity is not always successfully analogized prediction by Gibbs free energy.Mn and Cu are strong oxidants, the selectivity to NOx that improves in the time of can expecting them as independent component.Although the discovery raising to NO when using CuO separately _XSelectivity, but the Mn on aluminium oxide ₈Cu ₄When preparing, have with about 2 weight % or lower carrying capacity very big reduction to NO _XSelectivity.Therefore, the performance of this mixture is unpredictable.The HT WGS catalyst made from about 2 weight % mixed-metal oxides or lower carrying capacity all has the selectivity to NOx of good reduction, but still may producing, at least some known HT WGS technology have the CO promoter that higher NOx optionally is used for FCC, even they are made under enough low activity.

Can in the following example 4, further find the limiting examples of useful catalyst of the present invention.Best sample is to produce high CO ₂/ CO ratio has low NO simultaneously _X-Log (CO ₂/ CO) slope, promptly low NO _XForm optionally those.1%Fe ₆Cu ₂Mn ₂La ₂O _x, 0.5%Fe ₈Cu ₄, 0.5-2%Mn8Cu ₄And 1%Mn ₈Cu ₃Ni ₁Attractive especially.The most promising sample among the comfortable embodiment 3 of sample source in the table 2 under the high carrying capacity.If therefore batching makes under low carrying capacity among the embodiment 3, just may be extremely successful.Similar promising batching also may be derived from still unexplored WGS or perovskite prior art.

The successful sample of embodiment 4 all prepares on the Puralox alumina support.Other carrier also can be suitable for, for example the Puralox carrier of Si modification, mullite and calcined kaolin carrier.Preferred vector is a micro-ball gamma aluminum oxide.

The Puralox alumina support is the microspheroidal material that only contains transitional alumina.Can infer, can be by using adhesive, for example silica colloidal, silica-alumina, aluminium oxide, aluminium chlorine hydrol (chlorohydrol) etc. may be come the aluminium oxide of the granular or peptization of spray-drying by kaolin or other fillers dilute and effectively replace.It is valuable reducing the carrier cost, because may need a large amount of promoter.

Generally speaking, successful FCC CO promoter should have other FCC catalyst and the typical physical property of additive.This class specification is known, but generally, their average particle size particle size should be about 50-150 millimeter, usually about 70-85 micron, the falling bodies bulk density is about 0.7 to 1.1 gram/cubic centimetre, and their wearability should be with suitable by the standard of any appointment in several wear tests.

Diluting under the situation of promoter by forming microballoon with the filler spray-drying attempting, may be favourable forming before the microballoon the metal oxide pre-deposition on particulate alumina or other catalyst carrier.It is active and stable that this may be improved.This within the scope of the invention.

The deposition of reactive metal oxides on carrier can be by any known mode, and the method for the WGS catalyst that especially known preparation is successful is carried out.For the WGS Preparation of catalysts, metal nitrate is dissolved into dipping, drying and calcining are preferred then in the water.Deposition-precipitation is another the most suitable mode that is used to prepare the WGS catalyst.Calcining in oxygen or air under at least 800 temperature changes into oxide with slaine.Have been found that it is useful calcining 2 hours under 1400 °F in opening wide pallet.

About the preparation of perovskite oxidation catalyst, many prior aries are arranged.Under the early stage situation of majority, by with pure-oxide, carbonate or hydroxide ball milling together, then in the temperature that raises, at least 600 ℃ of following calcinings prepare perovskite usually.Usually by the co-precipitation of mixing water gel, calcining is carried out to make the perovskite of not load then in preparation afterwards.Recently, preformed carrier is flooded dry and calcining with mixing salt solution.The program of this nearest use mullite carrier is the most attractive, and just this material should prepare under enough low CO oxidation activity to obtain lower NOx formation selectivity.

Whelan (3,885,020) and other people provide and can be used for optimizing the rare earth metal of performance and the theory of transition metal perovskite catalyst operation.Structural vacancy is considered to improve oxygen-ion conductive, and these can use the metallic atom with special diameter to come further modification.This just has long inventory, for example Zr, Sn or Th, alkaline-earth metal, and the transition metal that uses.But, be not that the particular combinations of element in perovskite or other structure constitutes basis of the present invention.The invention reside in, these known base metal oxide combinations and structure are used to form has the CO promoter that the CO that is lower than appointment promotes activity.

Do not determine definite limit as yet to best operation promoter activity or reactive metal carrying capacity.The underlying parameter that decision is speculated as the superheating process of this improved root is the kinetic rate constant of promoter diameter of micro ball, per unit weight promoter microballoon, CO and the O in the microballoon ₂The heat transfer coefficient of the thermal diffusion coefficient of diffusion coefficient, catalyst inside and catalyst outside, and reaction heat.Particle diameter is subjected to the specification limits of FCC catalyst.Diffusion coefficient has less relatively flexibility under process conditions, but can make slight improvements by change pore size distribution under the wearability constraint.In fact, this makes the kinetic rate constant of per unit weight promoter microballoon become the unique channel that influences problems of excessive heat.The speed constant that reduces the per unit weight additive can be by making additive under than low activity metal carrying capacity or by using active lower batching to realize under constant carrying capacity.

Some tests about Pt promoter show that 80ppm Pt has than 8ppm or the higher per unit Pt activity of 800ppmPt.This efficiency factor that is hinting 80ppm Pt is greater than 1, and this microballoon is overheated.The efficiency factor of 8ppm Pt is doubted to being 1, thus this catalyst do not have overheated.The 800ppmPt sample has been owing to eliminated mass transfer limit under overheated kinetic effect, has the activity with the similar per unit Pt of 8ppm Pt, and has the efficiency factor near 1.This approximate showing, the kinetic rate constant of per unit weight promoter microballoon that is used for the CO promoter of FCC should be approximately less than 10% of the Pt promoter activity that contains 500-800ppmPt on aluminium oxide, even less than 1%.Under the supposition that we use, must have certain limitation to activity, even do not determine definite qualification as yet.

Do not need to determine that accurate speed constant is suitable for this activity constraint.Therefore, this CO oxidation additive must with in the FCC catalyst as 500ppm Pt/Al ₂O ₃Promoter is given at least 10 times amount of amount, and preferred about at least 100 times amount is used to obtain identical or suitable CO conversion ratio or CO ₂/ CO ratio.These two kinds of additives will carry out comparison on fresh active basis.It is about 1-50 weight % of the total materials of FCC catalyst that this regulation causes base metal oxide promoter to give the magnitude of amount.Can use nearly 20 weight %, giving of preferred 5-10 weight % measured.10% give the amount additive for what have 1 weight % base metal oxide carrying capacity, equilibrium catalyst has the base metal oxide that adds through promoter of about 1000ppm.

If must use the CO promoter of 10 weight % in the total materials of FCC catalyst to give amount so that the NOx selectivity minimizes, this brings the challenge that reduces the carrier cost thereupon.By with active base metal oxide pre-deposition to aluminium oxide, and with this aluminium oxide kaolin, the optional adhesive spray-drying of use, the low-cost SA promoter of calcining formation can be made not expensive promoter.Can follow FCC catalyst or additive that identical flow scheme manufacturing is contained zeolite and other Cracking catalyst composition.At last, this metal salt solution can be mixed with colloidal alumina, and the cheap carrier of dipping altogether, for example kaolin microsphere or FCC catalyst, aluminium oxide makes metal oxide stabilityization better than independent carrier.With alumina sol pre-preg kaolin microsphere is attractive especially.

Standard reaction engineering practice indication under the situation that has diffusion and heat transfer limitations, must be measured under the actual process condition conversion ratio and optionally influence.For example the danger of relaxing these restrictions is being emitted in test at a lower temperature, may produce incorrect conclusion.Therefore must under representative regenerator temperature, carry out suitable test.We have used 1300 °F, but 1200-1400 temperature also may be suitable for the analysis of specific FCC apparatus.If FCC apparatus moves under low regenerator temperature, the influence of overheating effect is lower, and can use more highly active base metal oxide to hang down NOx promoter.On the other hand, if a device has the regenerator of heat, problems of excessive heat can be more serious, and even may need lower metal oxide carrying capacity to improve selectivity.Because temperature is to forming NO _XThe systematic influence of Gibbs free energy of stoichiometric reaction, can infer, higher regenerator temperature also may require to change the promoter batching.The NO of given metal oxide batching under 1350 _XSelectivity may be improper, even this class batching is suitable under 1300 °F.

The 1000ppm base metal oxide expectation of adding in the FCC catalyst should be to the coke and the H of riser side ₂Output has influence.The CO that preferred formulations has higher per unit metal oxide promotes activity, thereby makes STRENGTH ON COKE and H ₂The output influence can minimize.If use this class greater activity mixed-metal oxides, then this should not make the activity of per unit weight promoter be increased to exceed desired limit, because this can increase NO _XOn the contrary, the benefit than high specific acitivity of mixing base metal be considered to additive originally on one's body base metal oxide carrying capacity reduce, wherein in the total materials of FCC catalyst, use identical additive to give and measure.At last, what deserves to be mentioned is, long catalyst contact-time test, for example MAT or FFB have amplified metal generation H ₂Activity with the pollutant coke.Circulation pilot-plant result more can represent the industry influence.

Embodiment

By the provisional application U.S.60/741 that submitted on December 1st, 2005, the U.S.60/782 that on March 15th, 331 and 2006 submitted to, 501 and U.S. serial (Docket 5187B) described in method, test CO combustion improver of the present invention and contrast property promoter, their full content is incorporated herein by this reference.Generally speaking, the test gas that in the described method of above-mentioned application, makes promoter and distribute with time dependent air/fuel (being characterized by λ scanning) to send into contacts with air.In various conditions, measure combustion product.

Find experimental basis in particle in the FCC regenerator and the gas stream.Figure 15 represents FCC regenerator and particle flux wherein.Label 10 is represented the FCC regenerator.In practice, the coke catalyst that will give up is discharged and to be delivered in the regenerator fluid bed 12, sometimes in container 10 edges that have as the tangent line inlet shown in 14 that enters the mouth, uses sometimes to make material more be dispersed in the center that device on the bed is delivered to bed 12.Usually, introduce air via near the grid bed 12 bottoms 16.Grid 16 supply oxygens are so that the coke burning on the catalyst.Usually, regenerator 10 can hold about 300 tons of fluidized catalysts, the bed 12 can for about 10 feet dark.For the bed under turbulent flow fluidisation situation, superficial gas velocity can be about 3 feet per seconds.The air that enters at air grid 16 places forms big bubble or even streamline in catalyst bed 12.These bubbles or streamline are along with bubble rises catalyst entrainment to the surface 15 of bed 12.Can fully mix in vertical direction owing to bubble and streamline mutually although have been found that catalyst, catalyst is radially or may fully not mix on the angle, so that may have composition gradient any depths in the plane at bed 12 tops 15.

The inventor believes, gas phase can take place when catalyst moves up and down in zone of regenerator form circulation.This circulation is represented with arrow 18.16 places begin at the air grid, and catalyst entrainment is shifted to the top 15 of bed 12 in bubble and in about 1 second, at this, be rich in combustion product in the atmosphere.More be rich in oxygen along with gas phase becomes, catalyst is downward through the dense newborn phase of bed 12 from here.According to the superficial velocity of regenerator, the actual time of returning the air grid may be less to 3 seconds.But we are with operating the fluidizing velocity (part is because the instrument restriction) that this representative is much lower 3 minute circulation timei.When catalyst is finally got back to air grid 16, repeat this circulation.This circulation repeats indefinitely, and irrelevant with the regenerator time of staying (total materials/external circulation rate).This internal oxidation reduction circulates in the design of former test method and is left in the basket.The device of test usefulness is shown among Figure 16.

With reference to Figure 16,, use the design of glass bushing gas syringe for fluidized-bed reactor 20.At reactor 20 tops, air is flowed through and is introduced central tube by pipeline 22, and with CO ₂/ CO/SO ₂/ H ₂O flows through by the annular space (not shown) between pipeline 24 inlet tubes.Gas syringe is inserted in the fluid bed, preferably be inserted into the fluid bed bottom, to prevent that entering bed 20 reacted between the admixture of gas in the past.As shown in the figure, the bottom of reactor 20 is to have the cone of little perforate but not frit.Via the pipe (not shown) of reactor 20 bottoms, provide via pipeline 26 and contain HCN, NH via pipeline 28 and 30 ₃, NO _XAnd H ₂Fluidizing gas stream (the N of O ₂Or Ar).Four port switch valves 32,33,34 and 35 can make reactant import reactor 20 by the bypass line 36 that heats with argon gas.Air, CO ₂/ CO/H ₂O/SO ₂Mixture and HCN/NH ₃/ NOx/H ₂The O injection point closely is arranged in together, in about 1 centimetre of the preferred each interval, thereby gas can be mixed under fluid bed covers.Realize gas analysis by FTIR gas analyzer 40 and mass spectrograph.This process gas requires dilution before analyzing, but these analyzers have enough detection limits usually.But the mass spectral analysis difficulty of burning gases is especially for N ₂And NH ₃Mensuration.Use and oxygen analyser 42 the FTIR gas analyzer that joins of coupling mutually with the air chamber that can under 450 or higher temperature, move.But the analyzer of these types can not measuring N ₂, H ₂And H ₂S, and can not be SO ₃Calibration is provided.

Use post-reactor catalytic converter 50 to help gas analysis.For example can form H with the percentage level by water-gas shift reaction ₂, but H ₂Can not analyze by FTIR.In order to overcome this point, with reactor stream via pipeline 52 and 53 and N ₂Or at N ₂In 0.5%O ₂Mixing diluents, and with this mixture via pipeline 56 by the Pt oxidation catalyst 58 under 1300.Diluent at first passes through cross valve 57 via pipeline 54, and can lead and mix with reactor stream 53 and via pipeline 56 guiding catalyst 58, maybe diluent can be led purging (flush) catalyst 58 via valve 57, and make from the reactor stream of pipeline 53 and walk around catalyst 58.Oxygen in the diluent is enough to any H ₂Change into H ₂O and with H ₂S changes into SO ₂/ SO ₃(major part is SO ₂).The pipeline and the accessory that are used to make up reactor 50 be glass or use protective coating, for example Sulfinert SiO ₂Preliminary treatment is to prevent absorption and high temperature vulcanized.NH ₃Also mainly change into NO with HCN _XTherefore, with pipe-line system the use of this class reactor of the online and off-line of reactor can reasonably be measured completely, even use standard C O ₂-CO-SO _X-NO _XThe continuous blow-down monitor.

Generally speaking, make and to contain 20% experimental supplement and 80% standard zeolite FCC mixture of catalysts and 1500 following steam treatment 2 hours.The mixture that steam treatment is crossed further mixes steam treatment FCC catalyst and the 10% undiluted fresh additive as 50% steam treatment additive agent mixture, 40% no any additives subsequently.Therefore the mixture of each recombination contains additive and 10% additive without steam treatment that 10% steam treatment is crossed, without any the zeolite FCC catalyst without steam treatment.Then 2 gram gained 50-40-10 mixtures are further restrained the FCC catalyst dilution that steam treatment are crossed with 18, and be placed on reaction zone and be in 1300 the above-mentioned fluid bed experimental rig.Make the CO that contains the representative amount ₂, CO, H ₂O, O ₂, SO ₂, NO, HCN, NH ₃With the test gas of inert diluent with the FCC regenerator of the E-cat operation that contains 2% additive typically with respect to the air speed of additive (about 107,000 hours ^-1) enter into the catalyst mixture place in the reactor.After operation about 30-60 minute, catch the effluent analysis and be used for report.

The noble metal promoted agent is tested under the situation that does not have the steam treatment additive usually, on the contrary fresh additive is sneaked into and above restrains chargings to form 20 in the used identical steam treatment FCC catalyst.

Fluid bed performance test reactor 20 be have conical base and do not have frit 1 " the diameter quartz ampoule.Gas manifold supply NO/H ₂O, NH ₃With the independent materials flow of HCN in diluent Ar, these materials flows mixing are carried by the bottom fluidization pipe with constant 165STP cc/min then.CO ₂/ CO/SO ₂/ Ar and air velocity summation are constant in 95STP cc/min, but these independently materials flow systematically change.The cleaning gas that also uses some kinds of number cc/min is to keep-up pressure and Other Instruments does not have condensate and corrosion thing.20 grams are tried catalyst be contained in the reactor, and around the feed gas injection point.These three kinds of feed gas are being tried mixing under the catalyst covering, and bubbling passes through this bed, and leaves reactor via Guartz filter.Three district's heaters are centered around around the reactor, and the zone that wherein is higher than the fluid bed top is 800 operations down, and the zone that is lower than it is 1300 operations down.Can use a thermocouple, and hold it in the air syringe pipe interior, extend to injector tip but do not exceed.Downstream line is a stainless steel.Hot pursuit high temperature GC switch valve and pipeline under 450 or higher temperature.The N that adds 2LPM ₂Or at N ₂In 0.5%O ₂Be heated to response time and the linearity of 230 ℃-240 ℃ FTIR equally with improvement as diluent.The downstream is gas-drying apparatus and oxygen analyzer again.

With air and CO ₂/ CO (fuel) gas is not sent into reactor with stable state.On the contrary, the method for following aforementioned U.S. Provisional Application is carried out ratio circulations such as air/fuel.Normally used parameter is 97% OTR, 3 minute circulation timei, the 2%CO/ under λ=1 ₂%CO ₂/ 4%H ₂O (stoichiometric mixture), and about 279ppm SO ₂, 389ppm NO, 391ppm NH ₃With 448ppm HCN.This group parameter finishes to produce about 7.5%O in circulation ₂About at the beginning of the cycle 2.3%CO and CO ₂For security consideration, keep low CO concentration.

Embodiment 1 test method

In this embodiment, directly get around the concentration that three air/fuels (λ) circulation is measured in reaction when entering analyzer in reactor feed, referring to Fig. 2 and 3.CO/100 show with fluid bed in the exponential shape of the similar fuel gas of combustion product.O ₂Have the shape opposite with CO.Vertical dotted line is represented the charging time that (be respectively λ＜1 or＞1) transforms between rich fuel and poor fuel.Measured HCN, NH ₃With NO constant in time.These concentration that record are (260/2260) dilution, so reactor level is much higher.Calculate the material balance of nitrogen, the result is about 0-5ppm N ₂, show the accuracy of this method.SO ₂Follow CO concentration, and the well extremely about 5ppm of sulphur material balance, but N ₂All higher with the S balance to 0.Below some results provide as integration output in three λ circulation.Under the situation that can separate poor fuel and rich fuel data, they provide separately.

Embodiment 2. contains comparative catalyst's goods of noble metal

By using 500ppm platinum, prepare CO promoter as the metal impregnation calcined kaolin microspheres.Do not have under the steam treatment by with this promoter with separately in 4 hours FCC catalyst mix of 1500 following steam treatment, test this and other noble metal promoted agent.Sneak into promoter so that the Pt concentration in the mixture is about 0.5ppm Pt.

The USP-500 CO promoter that BASF Catalysts LLC (predecessor is Engelhard Corp.) sells is contained 500ppm Pt on the Puralox alumina support.

By with 8ppm Pt dipping Puralox carrier, make Pt promoter.

By with 500ppm Pd dipping Puralox carrier, make palladium promoter.

With the earth solution dipping Puralox that contains cerium, dry then, calcining with 500ppm Pt, Pd or Rh dipping, are made rare earth modified noble metal (PM) CO promoter then by at first as known in the art.

The all fresh use of all these PM promoter also mixes as in the kaolinic situation of Pt/ to about 0.4ppm PM.

The comparative catalyst that embodiment 3. usefulness base metal oxides are made

By mixed solution is impregnated into as above the identical Puralox that uses microsphere supported on, dry then, then 1400 calcinings down, make the base metal catalysts of two series.Hydrated metal nitrate is dissolved in the water together to be formed on the pore volume of integer number volume available in the carrier, because solubility has limited desired multiple dipping sometimes.These two series all contain the mixed-metal oxides that 10 weight % add.First series is at A ₁Fe ₂O ₄On version, second series is A ₁Mn ₂O _xThe variation of basic recipe.The metal atomic ratio and the metal oxide stoichiometry that are used for carrying capacity calculating are shown in table 1.These only are at NO under constant CO promotion level _XThe output aspect quite maybe may slightly good comparative sample.These base metal promoter are tested as aforesaid 50-40-10 mixture, but minority is more being moved to be provided at low CO under the high-speed ₂Data under the/CO ratio.

Carry out the λ scan test, and find NO from poor fuel-side (corresponding to the gaseous environment of the bottom of regenerator dense bed) _XThe highest, and improve along with the raising of promoter activity.For the poor fuel meat of this circulation, the NO of integration in time _XOutput and L0g (CO ₂/ CO) roughly be linear, so slope is quite constant under air speed, is the characteristic of promoter.Table 1 is listed the result and the non-additive benchmark that can get and is given amount with typical platinum.Fully the equilibrium catalyst that promotes produces the CO of 10-20 ₂/ CO result.The per unit metal active of base metal promoter that contains the 2000ppm base metal oxide in mixture is than low at least 4 magnitudes of platinum additive, but NO _XSlope of a curve (NO _XSelection rate) still similar with platinum.

Table 1. is at 10 weight %MO _XUnder the carrying capacity and with respect to additive at 107,000 hours ^-1The contrast water-gas shift carbon monoxide-olefin polymeric of following test

Contrast	Fe	Ni	Cu	Zn	Co	Mg	Ca	Mn	Integration CO 2/CO	Integration NOx/Log (CO 2/CO)
											1	8	3							18.1	12.3
2	8	4							21	13
											3	8	5							16	14
4	8		4						162	9.4
											5	8			4
6	8				4
											7	8	2	2						20	12.6
8	8	2			2
											9	8	2				2
10	8	2					2		13	19
											11	8	1					3
12	8						4		9	17
											13					1			1
14					2			1	4	19
											15					3			1
16					1			2
											17	1							2	10	12.6
18		1						2	5.4	13
											19			1					2	50	11
20					3		1	8
											21	3						1	8	20	9
Blank sample	---	----	---	---	---	---	---	---	1-2	---
											Pt promoter	---	---	---	---	---	---	---	---	10-1000	12-18
MOx	Fe 2O 3	NiO	CuO	ZnO	CoO	MgO	CaO	MnO 3	Mol/mol	Umol

Embodiment 4 catalyst of the present invention

Aforementioned base metal oxide activity of such catalysts is more much lower than the general PM catalyst that uses.The diameter of alumina carrier particles only is about 80 microns, and fluid bed is considered to very well provide heat transfer.Therefore, do not consider to conduct heat and the possibility of mass transfer limit and any influence of this class restriction in this area.Cu ₁Fe ₂And Cu ₁Mn ₂Prescription obtains the highest CO under 10% carrying capacity ₂/ CO ratio, but still have higher relatively NO _XUse data in the past as guidance, but the total metal oxide carrying capacity is reduced to 0.5-2.0 weight %, prepare the version of these prescriptions.Also under 10 weight % carrying capacity, prepare four kinds of metal atomic ratio prescriptions, change any effect of carrying capacity with direct test.Hydrated metal nitrate is dissolved together and be impregnated on the alumina support.With these material dryings, calcining mixes, and steam treatment is also prepared to be used for test as the 50-40-10 mixture as carrying out in the past.But, under the situation of total metal oxide carrying capacity on the additive less than 10 weight %, carried out less dilution in the past at active testing, thus can be as previously used in reactor feed test 2% and 1% sample under the identical active base metal oxide of 2000ppm.(base metal that still, in the charging of 20 grams, 0.5 weight % carrying capacity additive, only has 1000ppm).

Traditional idea makes people estimate CO ₂/ CO does not change with the metal oxide carrying capacity on the promoter.But, unexpectedly, CO ₂/ CO result becomes with carrying capacity really, wherein finds to see Table 2 by maximum CO conversion ratio under medium carrying capacity.The most surprisingly, for constant metal atomic ratio and CO ₂/ CO, NO _XOutput greatly reduces under low carrying capacity.The NO of this improved reduction _XSelectivity is better than containing or not containing the noble metal promoted agent of rare-earth modifier also convincingly.

Table 2

Test number	Fe	Ni	Cu	Ca	Mn	La	Wt％MOx	CO 2/CO	NOx/ Log(CO 2/CO)
										22	8	1	3				1％	207	6.5
23	8	1	2	1			1％	35	7.1
										24	8	1	2		1		1％	40	7.6
25	8	1	2			1	1％	27	7.3
										26	6		2		2		1％	32	7.8
27	6	1	3		2	2	1％	42	8.3
										28	6		2		2	2	1％	65	3.9
29	6		3		1	2	1％	48	5.9
										30	8		4				10％	41	10.9
31	8		4				2％	282	6.6
										32	8		4				0.5％	163	4.8
33			4		8		10％	79	10.2
										34			4		8		2％	101	5
35			4		8		0.5％	35	4.9
										36	3			1	8		10％	12.6	15.5
37	3			1	8		1％	9.1	5.8
										38		1	3		8		1％	170	6.0
39	2		1	1	8		1％	40	5.6
										40	2	1		1	8		1％	10.9	4.4
41	1	1	1	1	8		10％	40,1715	10.4，7
										42	1	1	1	1	8		1％	10	3.1
43	1	1	2		8		1％	46.5	5.2

The CO oxidation is not structure sensitive allegedly, but the avtive spot structure is of crucial importance in selective oxidation reaction.Can think that this class formation sensitiveness is the NO that reduces _XThe reason that selectivity is improved.Do not wish to be limited by any theory, we believe that the additive with higher base metal oxide carrying capacity is all restricted in mass transfer and heat transfer.For very high activity or carrying capacity, because extreme mass transfer limit, efficiency factor is less than 1.Under medium activity and carrying capacity, the influence of overheated index surpasses mass transfer limit and efficiency factor greater than 1.Additive microballoon temperature may obviously surpass average bed temperature, and makes the selectivity variation and increase NO _XUnder minimum carrying capacity, additive microballoon temperature may be similar to bed temperature, and the NO to reducing _XSelectivity may be more favourable.

As above provide in the table 1 and 2, for contrast PM catalyst, contrast base metal oxidation/water-gas shift catalyst and low activity of the present invention and the low NO of carrying capacity base metal under 10 weight % carrying capacity _XCO promoter, poor fuel-side per unit integration (CO ₂+ CO) NO _XThe CO of the poor fuel-side integration of integration output vs. ₂The result of/CO ratio is plotted in figure below together.Operate like the PM additive kind: traditional 500ppm Pt additive, the low carrying capacity of the 8ppm of Pt, use Pd all after adjusting, to produce similar CO ₂/ CO result.The PM of use on rare earth modified aluminium oxide can provide the slightly good fresh NO of (reduction) poor fuel-side _XSelectivity.Some 10% carrying capacity base metal oxide prescriptions may also slightly improve, but the verified normal condition that is in.But, many 0.5%-10wt% base metal MO that are designated _XSample significantly improve.But this group drawing data among Fig. 4 is included in 10 weight %MO _XUnder four samples, this has blured the deciphering of this figure.NO among Fig. 5 _XNO optionally _X/ Log (CO ₂/ CO) measurement result confirms the importance and the practicality of the present invention of carrying capacity effect as the figure of the function of base metal oxide carrying capacity on the additive.This as if can be owing to microballoon overheated or NH ₃-HCN is oxidized to NO _XStructure sensitive property or NO _XSCR on additive of the present invention (SCR).

Embodiment 5

The performance that compares the additive of the present invention and prior art now in detail is to illustrate practicality of the present invention.

Sample is: the FCC catalyst that non-additive steam treatment is crossed and is enough to realize 22 CO ₂The fresh 500ppm Pt/Al of/CO ratio (by the integration of poor fuel-side data) ₂O ₃The identical base metal catalysts that additive mixes is enough to realize CO ₂/ CO=21 at CePr/Al ₂O ₃The 500ppm Pd that steam treatment on the additive is crossed is for making CO ₂/ CO=22 gives the Cu on the Puralox aluminium oxide under the 0.5 weight % carrying capacity of measuring ₁Mn ₂O ₇The 50-40-10 of new CO promoter is fresh/mixture of steam treatment, and new partial combustion additive FeSbCuOx (CO ₂/ CO=2) the mixture of fresh/steam treatment, and be enough to reach 18 CO ₂The CuCePr/Al that the steam treatment that the fresh Pt promoter of/CO ratio is mixed is crossed ₂O ₃The NOx additive.

Can in bar chart 6, find the general introduction of the nitrogen compound output of integration in whole λ circulation.Independent line shows CO ₂/ CO ratio is at two kinds of samples that do not promote or approaching between the sample of four kinds of promotions, so accelerant N O _XGrade can being accepted shown in them like that.New promoter of the present invention produces than the Pt that represents the prior art situation, Pd/REO or the much lower NO of Pt+CuCe additive system _XAbout promoter of the present invention, as 2*N ₂The nitrogen output that output is represented is also higher, but the ammonia accessory substance is slightly higher than the situation of Pt and Pd.In any case but, NH ₃Be possible burn into N ₂Not control gas.

Below illustrate NOx and N ₂Transient state concentration.This CONCENTRATION DISTRIBUTION is stable in three circulations, shows this technology balance.The poor fuel and the rich fuel meat of this circulation are separated by vertical dotted line, also show the λ value as the function of time.As if Fig. 7 A shows that Pt and Pd promoter produce NOx in poor fuel-side, but rare earth adds λ and the CO that is equating ₂Improved the result under the/CO slightly.But, the CO that new promoter is equating ₂/ CO and λ value produce much lower NOx down, although still find poor fuel-side NOx.Rich fuel-side NOx is all much lower in all cases.In these cases, the rich fuel-side N of these promoter ₂Output is higher, but table 7B shows that frequently the NO of rich fuel-side is reduced into NH on the contrary ₃The NOx that this new partial combustion additive and comparative catalyst have seemed to remove nearly all adding, but may be that there are some residual incendiary effect and NO+NH in the side in bed ₃Reaction generates N ₂Nitrogen balance shows that the poor fuel-side generation of NOx causes poor fuel-side N ₂Deficiency, but all promoter all produce the N of a great deal of in rich fuel-side ₂Under-supply regional similar of the top of this rich incoming mixture and partial combustion bed or the air of completing combustion dense bed.

Other nitrogen material has been shown among Fig. 7 C.Pt+CuCe/Al ₂O ₃Additive agent mixture stays a large amount of unconverted ammonia near λ=1, but Pd/Ce/Al ₂O ₃Promoter has transformed all ammonia surprisingly as the partial combustion additive.This new promoter also stays the unconverted NH of a great deal of near λ=1 ₃All additives are all removed HCN fully, and exception is Pt/Al ₂O ₃Do not remove rich fuel-side residue fully.

Near the bottom of the dense bed the air grid is the highest usually for combustion product, the generating rate that comprises nitrogen material, because oxygen concentration herein is the highest.The result shows usually, HCN and NH ₃Under these high λ values, change into NOx with peak efficiency.In fuel-rich regions, be more prone to produce nitrogen, but in the desirable regenerator of completing combustion and excess of oxygen, do not have fuel-rich regions.Therefore necessaryly for low NOx promoter be to have high in poor fuel-side to N ₂Selectivity and low NOx output.The present invention shows this valuable characteristic.

The further comparison of the detailed performance of embodiment 6. promoter of the present invention

The λ scan test of embodiment 4 is passed through CO ₂/ CO classification, and with scheming relatively to the test of four kinds of different catalysts of the present invention and to fresh 500ppm Pd/Al ₂O ₃Test, also comprise the CO of catalyst of the present invention ₂/ CO ratio.It is being 107,000 hours with respect to additive ^-1GHSV under, test fresh Mn ₈Cu ₄Catalyst, but other base metal catalysts is tested as the 50-40-10 mixture.Bar chart Fig. 8 shows the total nitrogen compound output and the CO of integration ₂/ CO ratio.From this figure, know and find out that catalyst of the present invention is at constant integration CO ₂Have the NOx more much lower under the/CO than the noble metal of prior art.

Although CO ₂/ CO integration is similar, but the detailed CO shown in Fig. 9 ₂The shape difference of/CO curve shows that in fact the base metal oxide catalyst gos deep into poor fuel environment and have higher CO promotion activity.NOx advantage of the present invention therefore may than its seem big.

A pair of figure subsequently, Figure 10 A and 10B show N ₂Detailed transient response with NOx.Although the overall shape of these curves is similar, be clear that catalyst of the present invention is compared the more N of generation with prior art Pd in poor fuel environment ₂NOx still less far away.This shows near higher N dense bed bottom and air grid ₂Generating rate, wherein the generating rate of NOx precursor is the highest.Bar chart Fig. 8 shows that another main matter is NH ₃Detailed NH among Figure 10 C ₃Transient data shows NH ₃Reaction rate depend on λ value and catalyst.These transient datas are rich in dynamic information and connotation.All additives are all removed HCN.

Embodiment 7

New promoter the seeming of embodiment 4 has excellent (reduction) poor fuel-side NOx selectivity.Carry out GHSV research to confirm low NOx performance to two kinds in these promising additives.Also show contrast Pt under different GHSV and the test of Pd base promoter carried out side by side with new promoter.PM promoter all is fresh.The mixture test of the fresh and steam treatment additive of the Chang Zuowei 50-40-10 of new promoter sample, but several tests that additive fresh to all or that all steam treatment are crossed carries out seem and have identical selectivity, therefore are also included among the figure.Promoter of the present invention significantly lower NOx under constant CO oxidation activity is used in data acknowledgement among Figure 11.

Embodiment 8. OTR effects: partial combustion, completing combustion and excess air

OTR parameter in the λ scan model has determined the boundary between poor fuel and the rich fuel condition, and this compares the operation of regenerator under various burning degrees.

Using 1%Fe of the present invention ₆Cu ₂Mn ₂La ₂O _xChange the OTR parameter in the time of the single charging of catalyst.In table 3, be given under the highest CO feed rate this parameter to excessive %CO in the test reactor or excessive %O ₂Influence.This gas composition is intended to simulate the gas that leaves regenerator dense bed top.

Table 3

O 2Conversion ratio	99％	97％	86.7％	75.7％	65％
						Excessive CO	2.28％	1.91％	0％	---	---
Excessive O 2	---	---	0％	1％	2％
						Operation	Partial combustion	Partial combustion	Stoichiometry	Completing combustion	Completing combustion

Bar chart Figure 12 has summarized the influence to nitrogen material.It is found that the operation in the dense bed reactor model under high OTR causes NH ₃Wash-out.This is intended to simulate the clean reducing condition that exists at the dense bed top in partial combustion.Under the oxygen consumption that is lower than stoichiometric point 86.7% conversion ratio, under the degree of depth of all λ sweep times or regenerator dense bed, there is excessive oxygen, this is completing combustion.Under these conditions, ammonia and HCN selection rate are lower than 1%, and N ₂Total amount and output and partial combustion operation compare in fact and improve.Quite surprisingly, the NOx output of catalyst of the present invention is in fact littler under completing combustion model condition.But this additive also reduces for the activity that CO transforms.

As finding out in the CONCENTRATION DISTRIBUTION below, change the OTR parameter and cause CO ₂The relative quantity of/CO and air changes.Figure 13 A-D confirms this surprising result, catalyst promptly of the present invention at reactor with more air with still less during fuel handling, at excessive O ₂Under the condition, in fact produce more N ₂NOx still less.

Embodiment 9. is by the performance verification of coke burning

As the final checking of this novel low NOx promoter, at Fe ₆Cu ₂Mn ₂La ₂Carry out the coke burning under promoter exists, and compare with USP-500 platinum CO promoter.The FCC catalyst diluent of 2 gram 50-40-10 base metal additives and the 16 gram steam treatment of in fluid bed, packing into earlier.2 grams in 1300 fluid beds, pack then into by gas-oil cracking and the coking steam treatment catalyst to about 0.8 weight % coke.Combustion product gas directly generates, and promoter changes into CO with them ₂, NOx etc.Time adding 2 gram chargings repeatedly, this moment, coke contained the fresh promoter of further increase.The CO that obtains in gained NOx output and the coke burning ₂The curved line relation of/CO is plotted in 14.Data acknowledgement, low activity base metal promoter of the present invention under the actual coke burning condition and the NOx that under constant promotion level, produces be Pt promoter only about half of of prior art.

After-burning influences refining operation, and our device has been designed to eliminate any influence of after-burning to the result.In the end in the test, re-use promoter of the present invention, the current top area heater that is set to 1300 of using on fluid bed is with can after-burning.This is tested, and as was expected produces higher CO ₂/ CO, but NOx seems constant.The high and NH at the CO conversion ratio ₃Under the low situation of concentration, the possibility that after-burning influences total result is little.

Claims (10)

1. one kind is used to handle FCC regenerator flue gas to promote CO burning, reduce the CO oxidation catalyst of the NOx content in the flue gas simultaneously, it comprises: the mixture of base metal oxide, the carbon monoxide oxidation activity of described CO oxidation catalyst per unit weight catalyst under at least 1100 temperature comprise on aluminium oxide less than per unit weight 500ppm platinum catalyst the CO oxidation activity 10%, and be at least 0.2%.

2. the catalyst of claim 1, wherein said CO oxidation catalyst per unit weight activity of such catalysts under at least 1100 temperature less than per unit weight on aluminium oxide, comprise 500ppm platinum catalyst the CO oxidation activity 1%.

3. the catalyst of claim 1, the mixture of wherein said base metal oxide is provided on the metal oxide carrier.

4. the catalyst of claim 4, wherein said metal oxide carrier comprises the FCC Cracking catalyst.

5. the catalyst of claim 1, the mixture of wherein said base metal oxide constitutes the 5 weight % that are less than of described CO oxidation catalyst.

6. the catalyst of claim 1 contains the noble metal that is less than 75ppm.

7. the catalyst of claim 1, wherein the mixture of base metal oxide is not the perovskite form.

8. the catalyst of claim 1, wherein said CO oxidation catalyst comprises the hopcalite of Fe or Mn and Cu and inessential X, and wherein X is selected from base metal, rare earth metal, alkaline-earth metal and composition thereof.

One kind in regenerator regeneration FCC Cracking catalyst comprise flue gas is contacted with the CO oxidation catalyst of claim 1 with the coke on the burn off FCC catalyst and promote the carbon monoxide oxidation in the flue gas and can not form the method for excessive NO x.

10. the method for claim 9, wherein the CO oxidation catalyst is the particle that separates with the FCC Cracking catalyst.

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