CN105664978A - Moulding preparation method for composite-carrier-supported acidified Mn-Co-Ce sulfur-tolerant catalyst for low temperature flue gas denitration - Google Patents

Abstract

The invention relates to a moulding preparation method for a composite-carrier-supported acidified Mn-Co-Ce sulfur-tolerant catalyst for low temperature flue gas denitration and particularly provides the moulding preparation method for a low temperature flue gas NH3-SCR denitration acidified catalyst. The catalyst is a multi-component supported metal oxide-type catalyst which is prepared by supporting nitrates of Mn, Co and Ce in an impregnation manner onto a TiO2/SiO2 composite carrier prepared through a sol-gel method, and sulfating and roasting the catalyst. A honeycomb moulding preparation method is employed for moulding the powder catalyst. The catalyst has large specific surface area and low wall thickness and is improved in sulfur resistance. The invention also provides the preparation method of the catalyst.

Description

The low-temperature denitration of flue gas sulfur resistant catalyst molding method for preparing of composite carrier load type acidifying manganese cobalt cerium

Technical field

The present invention relates to the sulfur resistant catalyst molding method for preparing of a kind of low-temperature denitration of flue gas composite carrier load type acidifying manganese cobalt cerium, be specially a kind of low-temperature flue gas NH₃The molding method for preparing of-SCR denitration acidifying catalyst, forming technique adopts cellular forming preparation process, belongs to environmental technology field.

Background technology

The thermal power plant of China still adopts coal as fuel mostly, especially thermal power plant, the north, containing substantial amounts of NO in coal fuel flame_x. SCR method is the denitration technology that current commercial Application is the widest and effect is best. SCR catalyst is applied in industrial smoke passage so that flue gas passes through catalyst, so catalyst must be shaped design so that catalyst has a definite shape, and has certain physical characteristic, chemical characteristic and certain mechanical strength. But current industrial board-like shaping of catalyst preparation method, corrugated preformed catalyst preparation method increase the flue gas resistance by catalyst, it is under the washing away of flue gas and flying dust, its active component ratio that can run off is more serious, the ratio that catalyst activity reduces is very fast, service life is substantially reduced, the economic cost of raising.

Mn is catalyst based is one of current Low-temperature catalyst study hotspot. Substantial amounts of research work has been carried out in recent years about the catalyst based Chinese scholars of Mn. The d orbital electron of Mn is in underfill state, MnO_xThere is multiple oxidation state, in redox cycle can effectively activated gas mutually in O₂, therefore there is efficient catalysis activity in SCR reacts. With MnO_xFor active constituent loading in TiO₂、Al₂O₃Deng on carrier, active specy is mainly MnO₂, and a small amount of Mn₂O₃. The NO of SCR reaction_xClearance is main and MnO₂Relevant, and to N₂Selectivity mainly by Mn₂O₃Determine. It addition, with Mn for main active component, usually through adding other metal-oxides, thus improving the physical property of catalyst, improve the activity of catalyst or stability and resistance to SO_2. Conventional metal adds auxiliary agent Cu, Fe, Ce, Ni etc. Ce is conventional metal promoter, and Ce has stronger storage oxygen and the ability of release oxygen, adds, by Ce, the Mn-Ce-O metal composite oxide formed or is carried on TiO₂Mn-Ce loaded catalyst on carrier, all to NO under low temperature_xConvert and there is significantly high activity.Such as MnO_x-CeO₂Can to the denitration effect of nearly 98% at 200 DEG C. It addition, the interpolation of Fe and Co can also improve the activity that catalyst is at about 200 DEG C. By the doping of metal, the specific surface area of catalyst, pore volume, oxygen storage capacity, surface acid center and acidic site quantity all change, thus changing the catalysis activity of catalyst.

After low temperature catalyst is placed in desulfurization and dust removing units, the therefore SO in flue gas₂Concentration is relatively low, but due to SO₂At low temperatures that the poisoning effect of SCR catalyst is even more serious, therefore the resistance to SO_2 of catalyst is also the problem that must take into. Although TiO₂As carrier to SO₂There is certain resistance, but Mn/TiO₂The resistance to SO_2 of catalyst is still that relatively low. Research shows can be improved the resistance to SO_2 of catalyst by the doping of some metallic elements, such as Ce, Sb, Fe etc. Ce metal-oxide adds the resistance to SO_2 that can significantly improve catalyst, and principle is SO₂Preferential and Ce forms cerous sulfate, thus suppressing generation and the deposition of catalyst surface ammonium sulfate and ammonium hydrogen sulfate. It addition, its resistance to SO_2 is also had material impact by the geometric configuration of catalyst, research shows, by adding SiO in carrier₂Form TiO₂-SiO₂Composite oxides, the V active constituent catalyst of load is to SO₂Significantly improve the resistances of 300～400 DEG C. SO₂Catalytic reaction is had simultaneously the impact of positive negative side, on the one hand, SO₂It is SO by catalytic oxidation₃, generate ammonium sulfate with ammonia or ammonium hydrogen sulfate be deposited on catalyst surface, thus covering catalytic active site and blocking catalyst hole. On the other hand, SO₂Process can improve the Bronsted acidic site of catalyst surface, thus promoting NH₃Absorption and NO_xConversion, therefore, a degree of sulphation can promote NO_xThe raising of conversion ratio.

One difficult point of Mn base low-temperature SCR catalyst practical application is that resistance to SO_2 is poor, therefore, improves the catalyst based resistance to SO_2 at low temperatures of Mn very necessary.

Prior art CN104289227A discloses a kind of low-temperature denitration of flue gas four component NH₃-SCR load type metal catalyst and preparation method thereof, it is that the nitrate with elements such as Mn, Co, Ce is carried on nanoscale TiO with infusion process₂-P₂₅, forming what multicomponent metal composite oxide obtained through roasting, catalyst has acidity and oxidisability, is conducive to NH₃At catalyst surface adsorption activation, improve the efficiency of denitration. But, resistance to SO_2 effect is poor at low temperatures for this catalyst.

Summary of the invention

For solving above-mentioned technical problem, it is an object of the invention to provide the sulfur resistant catalyst molding method for preparing of a kind of low-temperature denitration of flue gas composite carrier load type acidifying manganese cobalt cerium, be specially a kind of low-temperature flue gas NH₃The molding method for preparing of-SCR denitration acidifying catalyst, using transition metal as main component, with composite Ti O₂/SiO₂As carrier. Honeycomb moulding technology is adopted to prepare preformed catalyst.

Specifically, the present invention is achieved through the following technical solutions, including:

A kind of low-temperature flue gas NH₃-SCR denitration acidifying shaping of catalyst preparation method, it is characterised in that: adopt cellular molding method for preparing to sulphation support type Mn-Co-Ce/TiO₂-SiO₂Powder catalyst is shaped, and needs interpolation to need the auxiliary agents such as glass fibre, binding agent, water in forming process, carries out uniform temperature and dries extruded with roasting.

Wherein, glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent, binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

Find can promote the tensile ductility of preformed catalyst by adding a certain amount of glass fibre by substantial amounts of experiment; Powder catalyst is loose and mechanical intensity, makes catalyst form jelly by adding binding agent and water, is formed fine and close and has the moulding material of good mechanical strength.

Wherein, auxiliary agent contains effect that glycerol and ammonium hydrogen carbonate, glycerol and ammonium hydrogen carbonate play respectively further: glycerol: lubricant, ammonium hydrogen carbonate: pore creating material.

Due to add binding agent can not with beaded catalyst Homogeneous phase mixing to together with, (glass fiber addition is the 15% of catalyst gross mass, content of binder is the 20% of catalyst gross mass, water addition is the 25% of catalyst gross mass preferably further to add a certain amount of extrusion aid, glycerol add add that mass ratio is catalyst gross mass 5% for catalyst gross mass, the mass ratio that adds of ammonium hydrogen carbonate is the 5% of catalyst gross mass) so that catalyst has certain mechanical strength.

Experiment finds that when preformed catalyst goes out to grind after suppressing, catalyst bonds with grinding tool contact surface, can cause the breakage of catalyst after depanning, it is preferable that adds lubricant (glycerol: lubricant 5%) and makes catalyst completely go out mill smoothly.

Preferred version of the present invention be add a certain amount of pore creating material (the interpolations quality of glycerol be catalyst gross mass be 5%, ammonium hydrogen carbonate interpolation mass ratio be the 5% of total catalyst quality. ), it is greatly increased the specific surface area of molding rear catalyst.

Wherein, it is preferable that drying temperature described in described drying temperature is 80 DEG C of dry 3h, 100 DEG C of dry 3h, and 115 DEG C of dry 3h, altogether 12h, after molding, sintering temperature is at 300 DEG C.

Catalyst chemical of the present invention consists of SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂, wherein Mn, Ce and Ce mass fraction for being not 5%, 2% and 1%, TiO₂/SiO₂Middle SiO₂Mass fraction be 30～50%, utilize when preparing catalyst 0.1mol/L dilute sulfuric acid dipping 12h.

Aforesaid molding method for preparing, more specifically, comprises the following steps:

After catalyst and auxiliary agent mix homogeneously according to the above ratio, adding in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming, extrusion time controlled in 20～30min time.

Sulphation support type Mn-Co-Ce/TiO of the present invention₂-SiO₂Powder catalyst is prepared by following preferred preparation method, including: it is carried on TiO prepared by sol-gal process with the soluble-salt of Mn, Co and Ce metal with infusion process₂/SiO₂Complex carrier, after sulphation, the multicomponent load metal oxide type catalyst that roasting obtains.

More specifically, the preparation method of described concrete catalyst, including following preparation process:

(1): by dehydrated alcohol, acetic acid, deionized water 10:2:(0.5～1.0 by volume) mixing, stirring obtains solution A; Butyl titanate and dehydrated alcohol 5:13 by volume are mixed to get solution B; Then solution B is dropwise instilled in solution A, initially form to colloidal sol by magnetic stirrer, then according to SiO₂/TiO₂Middle SiO₂Mass fraction 30～50% weigh the spherosil SiO of a certain amount of 60～100 orders₂Add solution, continue stirring to forming gel;

(2): the aging 24～48h in the colloidal sol obtained ventilation under room temperature, form gel, then at 80～100 DEG C of drying in oven 12h, obtain white powder;

(3): by the white powder that obtains at tube furnace with 400～550 DEG C of roasting 2h, obtain TiO₂/SiO₂Complex carrier;

(4): the presoma of a certain amount of Mn, Co and Ce is dissolved mix homogeneously in proportion, adds a certain amount of TiO₂/SiO₂Carrier, continues stirring 1, active component Mn, Co and Ce load capacity respectively 5%, 2% and 1%, obtain pasty solid;

(5): the pasty solid at room temperature aging 24h in ventilation that will obtain, then at 90～110 DEG C of drying in oven 8～12h, with 500 DEG C of roasting 3h in tube furnace, black solid granule is obtained;

(6): black solid granule is impregnated in the sulfuric acid solution of 0.05～0.15mol/L 12h, then in 90～110 DEG C of drying in oven 6～12h, finally at tube furnace with 300 DEG C of roasting 2h, then pass through screening and obtain 60～100 final SO of purpose₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Solid catalyst.

The present invention relative to prior art, the technique effect played, including:

The present invention also aims to the preparation method that above-mentioned catalyst is provided. Carrier adopts sol-gal process to prepare, and active component adopts simultaneously infusion process to be carried on complex carrier, and carries out sulphation, and strictly controls sintering temperature, obtains the catalyst that high activity, sulfur resistance are excellent.

First the present invention have chosen low-temperature space and has the Mn-Co-Ce trimetallic catalyst of outstanding catalytic effect as the basis optimized, and uses composite Ti O₂/SiO₂As carrier, by optimizing TiO in carrier₂With SiO₂Ratio, it is determined that TiO₂/SiO₂Middle SiO₂Mass fraction be 30～50%. This catalyst 90ppmSO in reacting gas₂At low-temperature space, there is good NO under existence condition_xClearance. Further catalyst is carried out sulphation, define SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Catalyst system and catalyzing, further increases the resistance to SO_2 of catalyst.

At SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂In catalyst, Mn is primary activity component, and the interpolation of Co and Ce improves the reactivity of catalyst and widened reaction temperature window. TiO₂/SiO₂In complex carrier, by microsphere silica gel SiO₂Addition, improve the specific surface area of catalyst, it is suppressed that the crystal grain of catalyst generates, and is equivalent to reduce the unit volume load capacity of active metal component, reduces the wall thickness of catalyst, thus improving its resistance to SO_2.

When showing that glass fibre addition 15%, content of binder 20%, water addition are 25% by above experiment of single factor, the mechanical performance of preformed catalyst is best.

Accompanying drawing explanation

Fig. 1 is SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂The XRD of support type preformed catalyst characterizes spectrogram;

Fig. 2 is SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Support type preformed catalyst SCR circulates the impact of ramp cycle activity;

Detailed description of the invention

Introduce the realization of the present invention below by way of specific embodiments and the drawings and had the advantage that, but accordingly the practical range of the present invention should do not constituted any restriction.

The evaluation methodology of catalyst activity:

Detection method: use fixed-bed micro-reactor-nitrogen-oxide analyzer, detection system. Nitrogen-oxide analyzer, is T200H, adopts chemoluminescence method detection NO, NO₂、NO_x。

Concrete steps: put in fixed bed reaction pipe by the catalyst sample 100mg weighed up, pass into reacting gas, gas flow is 100ml/min. Reaction tube is the quartz ampoule of 9mm internal diameter. Adopting temperature-programmed reaction, heating rate is 1 DEG C/min.

Evaluation methodology: the catalysis activity of prepared catalyst can be passed through NO_xPercent reduction and corresponding active temperature are evaluated, and reduction conversion ratio computational methods are:

${\mathrm{NO}}_x\left(100\%\right)=\frac{C_0-C_1}{C_0}\×100$

In formula, C₀For nitrogen oxides porch concentration (mL/m³); C₁For nitrogen oxides exit concentration (mL/m³)。

1 one kinds of low-temperature flue gas NH of embodiment₃-SCR denitration acidifying Catalysts and its preparation method

A kind of low-temperature flue gas NH₃-SCR denitration acidifying catalyst, described catalyst is that the soluble-salt with Mn, Co and Ce metal is carried on TiO prepared by sol-gal process with infusion process₂/SiO₂Complex carrier, after sulphation, the multicomponent load metal oxide type catalyst that roasting obtains.

Described catalyst chemical consists of SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂, wherein Mn, Ce and Ce mass fraction for being not 5%, 2% and 1%. TiO₂/SiO₂Middle SiO₂Mass fraction be 30%. Following preparation method is adopted to obtain:

(1): mixed by dehydrated alcohol, acetic acid, deionized water 10:2:0.5 by volume, stirring obtains solution A; Butyl titanate and dehydrated alcohol 5:13 by volume are mixed to get solution B; Then solution B is dropwise instilled in solution A, initially form to colloidal sol by magnetic stirrer, then according to SiO₂/TiO₂Middle SiO₂Mass fraction 30 weigh the spherosil SiO of a certain amount of 60～100 orders₂Add solution, continue stirring to forming gel;

(2): the aging 24h in the colloidal sol obtained ventilation under room temperature, form gel, then at 80 drying in oven 12h, obtain white powder;

(3): by the white powder that obtains at tube furnace with 550 DEG C of roasting 2h, obtain TiO₂/SiO₂Complex carrier;

(4): the presoma of a certain amount of Mn, Co and Ce is dissolved mix homogeneously in proportion, adds a certain amount of TiO₂/SiO₂Carrier, continues the load capacity respectively 5%, 2% and 1% of stirring 1h, active component Mn, Co and Ce, obtains pasty solid;

(5): the pasty solid at room temperature aging 24h in ventilation that will obtain, then at 110 DEG C of drying in oven 12h, with 500 DEG C of roasting 3h in tube furnace, black solid granule is obtained;

(6): black solid granule is impregnated in the sulfuric acid solution of 0.10mol/L 12h, then in 110 DEG C of drying in oven 12h, finally at tube furnace with 300 DEG C of roasting 2h, then pass through screening and obtain 60～100 final SO of purpose₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Solid catalyst.

Wherein, the component Mn of described catalyst, Co and Ce presoma be all nitrate. Described catalyst is air atmosphere during roasting in tube furnace.

Low temperature nitrogen adsorption/desorption method is utilized to measure the specific surface area of catalyst, SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂The specific surface area of loaded catalyst is 301m²·g^-1. X-ray diffraction (XRD) is adopted to measure the average grain size of catalyst, for 9.8nm.

X-ray diffraction characterizes, and result is as it is shown in figure 1, crystalline phase corresponding to each diffraction maximum and crystal face mark in the drawings. Testing conditions: adopting Cu target K alpha ray, sweep speed is 6 °/min, scans 2 θ and ranges for 10～80 °, and voltage and current is 40kV and 200mA respectively. Titanium dioxide is Anatase, it does not have the crystalline phase of Mn, Co, Ce oxide detected, and active component is fine at catalyst surface dispersibility.

SO according to the above-mentioned variable concentrations sulfuric acid solution that embodiment is prepared by the method for catalyst activity evaluation dipping₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Catalyst carries out activity rating. The concentration of the sulfuric acid solution adopted respectively 0.05,0.10 and 0.15mol/L, and contrast with the catalyst before sulphation. Air inlet SO₂Concentration is 50ppm. Catalysis activity is as shown in Figure 2. When first set reaction, the NO of catalyst_xMaximum reduction efficiency is 99.5%. Corresponding reaction temperature is 250 DEG C. Catalyst prepared by embodiment has significantly high SO at low temperatures₂Resistance.

Catalyst SO prepared by embodiment₄ ^2--Mn-Co-Ce/TiO₂/SiO₂, the sulfuric acid solution concentration of employing is 0.10mol/L, at air inlet SO₂When concentration is 90ppm, it is circulated temperature reaction experiment, the activity of catalyst is evaluated, as shown in Figure 2. In initial program temperature reaction, NO_xMaximum reduction efficiency be 98.9%. Corresponding reaction temperature is 250 DEG C. After recycling 8 times, catalyst is at the NO of reaction temperature window 180～270 DEG C_xConversion ratio is maintained at more than 90%.

2 one kinds of low-temperature flue gas NH of embodiment₃-SCR denitration acidifying Catalysts and its preparation method

On the basis of the scheme of embodiment 1, the sulfuric acid solution being respectively adopted 0.05mol/L prepares described catalyst.

3 one kinds of low-temperature flue gas NH of embodiment₃-SCR denitration acidifying Catalysts and its preparation method

On the basis of the scheme of embodiment 1, the sulfuric acid solution being respectively adopted 0.15mol/L prepares described catalyst.

4 one kinds of low-temperature flue gas NH of embodiment₃-SCR denitration acidifying Catalysts and its preparation method

A kind of low-temperature flue gas NH₃-SCR denitration acidifying catalyst, described catalyst is that the soluble-salt with Mn, Co and Ce metal is carried on TiO prepared by sol-gal process with infusion process₂/SiO₂Complex carrier, after sulphation, the multicomponent load metal oxide type catalyst that roasting obtains.

Described catalyst chemical consists of SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂, wherein Mn, Ce and Ce mass fraction for being not 5%, 2% and 1%. TiO₂/SiO₂Middle SiO₂Mass fraction be 50%. Following preparation method is adopted to obtain:

(1): mixed by dehydrated alcohol, acetic acid, deionized water 10:2:1.0 by volume, stirring obtains solution A; Butyl titanate and dehydrated alcohol 5:13 by volume are mixed to get solution B; Then solution B is dropwise instilled in solution A, initially form to colloidal sol by magnetic stirrer, then according to SiO₂/TiO₂Middle SiO₂Mass fraction 50% weigh the spherosil SiO of a certain amount of 60～100 orders₂Add solution, continue stirring to forming gel;

(2): the aging 48h in the colloidal sol obtained ventilation under room temperature, form gel, then at 100 DEG C of drying in oven 12h, obtain white powder;

(3): by the white powder that obtains at tube furnace with 400 DEG C of roasting 2h, obtain TiO₂/SiO₂Complex carrier;

(4): the presoma of a certain amount of Mn, Co and Ce is dissolved mix homogeneously in proportion, adds a certain amount of TiO₂/SiO₂Carrier, continues stirring 1, active component Mn, Co and Ce load capacity respectively 5%, 2% and 1%, obtain pasty solid;

(5): the pasty solid at room temperature aging 24h in ventilation that will obtain, then at 90 DEG C of drying in oven 12h, with 500 DEG C of roasting 3h in tube furnace, black solid granule is obtained;

(6): black solid granule is impregnated in the sulfuric acid solution of 0.05～0.15mol/L 12h, then in 90～110 DEG C of drying in oven 6～12h, finally at tube furnace with 300 DEG C of roasting 2h, then pass through screening and obtain 60～100 final SO of purpose₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Solid catalyst.

Wherein, the component Mn of described catalyst, Co and Ce presoma be all nitrate. Described catalyst is air atmosphere during roasting in tube furnace. Gained catalyst has consistent NO with Above-mentioned catalytic agent_xClearance and resistance to SO_2.

5 one kinds of low-temperature flue gas NH of embodiment₃Prepared by the molding of-SCR denitration acidifying catalyst

Embodiment 1 is adopted to obtain low-temperature flue gas NH₃-SCR denitration acidifying catalyst, glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent, binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

Adopt following technique to be shaped preparation, after catalyst and auxiliary agent mix homogeneously according to the above ratio, add in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming. Described drying temperature is: drying temperature is 80 DEG C of dry 3h, 100 DEG C of dry 3h, 115 DEG C of dry 3h, altogether 12h, and after molding, sintering temperature is at 300 DEG C.

Extrusion time controlled in the 20min time.

6 one kinds of low-temperature flue gas NH of embodiment₃Prepared by the molding of-SCR denitration acidifying catalyst

Embodiment 2 is adopted to obtain low-temperature flue gas NH₃-SCR denitration acidifying catalyst, glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent, binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

Auxiliary agent contains glycerol and ammonium hydrogen carbonate further, the interpolation quality of glycerol be catalyst gross mass be 5%, ammonium hydrogen carbonate add mass ratio be the 5% of catalyst gross mass.

Adopt following technique to be shaped preparation, after catalyst and auxiliary agent mix homogeneously according to the above ratio, add in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming.

Extrusion time controlled in the 30min time.

7 one kinds of low-temperature flue gas NH of embodiment₃Prepared by the molding of-SCR denitration acidifying catalyst

Embodiment 3 is adopted to obtain low-temperature flue gas NH₃-SCR denitration acidifying catalyst, glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent. binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

Auxiliary agent contains glycerol and ammonium hydrogen carbonate further, the interpolation quality of glycerol be catalyst gross mass be 5%, ammonium hydrogen carbonate add mass ratio be the 5% of catalyst gross mass.

Adopt following technique to be shaped preparation, after catalyst and auxiliary agent mix homogeneously according to the above ratio, add in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming.

Extrusion time controlled in the 20min time.

8 one kinds of low-temperature flue gas NH of embodiment₃Prepared by the molding of-SCR denitration acidifying catalyst

Embodiment 4 is adopted to obtain low-temperature flue gas NH₃-SCR denitration acidifying catalyst, glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent. Binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

It is respectively the 5% of catalyst gross mass that auxiliary agent contains glycerol and ammonium hydrogen carbonate, glycerol and ammonium hydrogen carbonate further.

(glass fiber addition 15%, content of binder 20%, water addition are 25%, and the interpolation mass ratio of glycerol is 5%, and the interpolation mass ratio of ammonium hydrogen carbonate is 5% to add extrusion aid further. ), lubricant (glycerol, glycerol are respectively the 3% of catalyst gross mass), pore creating material (ammonium hydrogen carbonate is the 5% of total catalyst weight)

Adopt following technique to be shaped preparation, after catalyst and auxiliary agent mix homogeneously according to the above ratio, add in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming.

Extrusion time controlled in the 30min time.

Embodiment 9 mechanical strength test

Method of testing

The moulding material adopting embodiment 48 is tested, and test result is:

1. radial pressure utilizes omnipotent pressure testing machine, radial compression catalyst.

2. impact resistance 2.5m place is vertically lower throws, and measures catalyst breakage degree.

Radial pressure: comprcssive strength > 1MPa impact resistance: damaged degree < 15%

Above content is in conjunction with concrete preferred implementation further description made for the present invention, it is impossible to assert that specific embodiment of the invention is confined to these explanations. For general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, it is also possible to make some simple deduction or replace, protection scope of the present invention all should be considered as belonging to.

Claims (8)

1. a low-temperature flue gas NH₃-SCR denitration acidifying shaping of catalyst preparation method, it is characterised in that: adopt cellular molding method for preparing to sulphation support type Mn-Co-Ce/TiO₂-SiO₂Powder catalyst is shaped, and needs interpolation to need the auxiliary agents such as glass fibre, binding agent, water in forming process, carries out uniform temperature and dries extruded with roasting.

2. molding method for preparing as claimed in claim 1, it is characterized in that: glass fibre add mass ratio be 15%, the mixture consisting of polyethylene alcohol and water of binding agent, binding agent add mass ratio be 20%, to add mass ratio be 25% to water, surplus is powder catalyst.

3. molding method for preparing as claimed in claim 2, it is characterised in that: auxiliary agent contain glycerol and ammonium hydrogen carbonate further, glycerol add as catalyst, adding quality is the 5% of catalyst gross mass, and the interpolation mass ratio of ammonium hydrogen carbonate is the 5% of catalyst gross mass.

4. molding method for preparing as claimed in claim 1, it is characterised in that: described drying temperature is 80 DEG C of dry 3h, 100 DEG C of dry 3h, 115 DEG C of dry 3h, altogether 12h, 300 DEG C of roasting 3h.

5. molding method for preparing as claimed in claim 1, it is characterised in that: described catalyst chemical consists of SO₄ ^2--Mn-Co-Ce/TiO₂/SiO₂, wherein Mn, Ce and Ce mass fraction for being not 5%, 2% and 1%, TiO₂/SiO₂Middle SiO₂Mass fraction be 30～50%, utilize when preparing catalyst 0.1mol/L dilute sulfuric acid dipping 12h.

6. the molding method for preparing as described in claim 15 any claim, comprises the following steps:

After catalyst and auxiliary agent mix homogeneously according to the above ratio, adding in extruding grinding tool and carry out cellular molding, utilize tablet machine certain pressure to carry out squeezing out mold forming, extrusion time controlled in 20～30min time.

7. the molding method for preparing as described in claim 15 any claim, it is characterised in that wherein, sulphation support type Mn-Co-Ce/TiO₂-SiO₂Powder catalyst is prepared by method and prepares, including: it is carried on TiO prepared by sol-gal process with the soluble-salt of Mn, Co and Ce metal with infusion process₂/SiO₂Complex carrier, after sulphation, the multicomponent load metal oxide type catalyst that roasting obtains.

8. molding method for preparing as claimed in claim 7, it is characterised in that specifically include following preparation process:

(1): by dehydrated alcohol, acetic acid, deionized water 10:2:(0.5～1.0 by volume) mixing, stirring obtains solution A; Butyl titanate and dehydrated alcohol 5:13 by volume are mixed to get solution B; Then solution B is dropwise instilled in solution A, initially form to colloidal sol by magnetic stirrer, then according to SiO₂/TiO₂Middle SiO₂Mass fraction 30～50% weigh the spherosil SiO of a certain amount of 60～100 orders₂Add solution, continue stirring to forming gel;

(2): the aging 24～48h in the colloidal sol obtained ventilation under room temperature, form gel, then at 80～100 DEG C of drying in oven 12h, obtain white powder;

(3): by the white powder that obtains at tube furnace with 400～550 DEG C of roasting 2h, obtain TiO₂/SiO₂Complex carrier;

(4): the presoma of a certain amount of Mn, Co and Ce is dissolved mix homogeneously in proportion, adds a certain amount of TiO₂/SiO₂Carrier, continues stirring 1, active component Mn, Co and Ce load capacity respectively 5%, 2% and 1%, obtain pasty solid;

(5): the pasty solid at room temperature aging 24h in ventilation that will obtain, then at 90～110 DEG C of drying in oven 8～12h, with 500 DEG C of roasting 3h in tube furnace, black solid granule is obtained;

(6): black solid granule is impregnated in the sulfuric acid solution of 0.05～0.15mol/L 12h, then in 90～110 DEG C of drying in oven 6～12h, finally at tube furnace with 300 DEG C of roasting 2h, then pass through screening and obtain 60～100 final SO of purpose₄ ^2--Mn-Co-Ce/TiO₂/SiO₂Solid catalyst.