CN105642339A

CN105642339A - Catalyst for simultaneous desulfurization and denitration without reducing gas and preparation method

Info

Publication number: CN105642339A
Application number: CN201510893704.0A
Authority: CN
Inventors: 王承学; 刘鹏举; 王海博
Original assignee: Changchun University of Technology
Current assignee: Changchun University of Technology
Priority date: 2015-12-08
Filing date: 2015-12-08
Publication date: 2016-06-08
Anticipated expiration: 2035-12-08
Also published as: CN105642339B

Abstract

The invention discloses a catalyst for simultaneous desulfurization and denitration without reducing gas and a preparation method thereof. The catalyst can directly decompose oxynitride into nitrogen gas and oxygen gas, which are discharged then, and oxidize sulfur oxides into sulfur trioxide, which can be easily removed, in the absence of reducing gas (ammonia gas). The catalyst is composed of the following components in percentage by weight: 0.5 to 2.5% of ZSM-5 molecular sieve, 0 to 1.5% of CuO, 0-1.5% of K2O, 0-1.5% of CoO, 0 to 1.5% of Ni2O3, 0.5 to 2.5% of V2O5, and 0-1.5% of WO3; wherein CuO, K2O, CoO, Ni2O3, V2O5, and WO3 are active components. The catalyst is impregnated for one time or more, and then dried and burned before using. The catalyst has the advantages of easily-available raw material, low cost, simple preparation, good activity and stability, high desulfurization rate and denitration rate, and no secondary pollution (reducing ammonia gas).

Description

A kind of simultaneous SO_2 and NO removal catalyzer without the need to reducing gas and preparation method

Technical field

The present invention relates to chemical technology field, especially commercial catalysts field, specifically provide a kind of without the need to taking off the catalyzer except sulfurous gas in coal-fired flue-gas and oxynitride and preparation method while reducing gas.

Background technology

Along with the development of economy, the demand of coal is increased by China day by day, and ecotope is caused havoc by the exploitation of coal, and people to ecotope and healthy and safe pay special attention to. China first produces coal and utilizes the big country of coal in the world, and the burning utilization of coal is the SO of main mode, thermal power plant and discharged from coal-fired boiler₂And NO_XIt is the main source of current sulfur and nitrogen oxides, also becomes the principal element of restriction China's economic social development.

At present, compare coal-fired flue gas desulfurization and denitration technology that is ripe and that generally apply both at home and abroad and it is still " desulfurization method of limestone-gypsum and NH₃Selective catalytic reduction denitration (SCR) " technology, SO₂And NO_XImprovement respectively, have that floor space is big, equipment is complicated, investment and working cost height, by-product utilization are worth reducing gas low, that need secondary pollution problems, it is difficult to meet the environmental requirement of increasingly stringent. Therefore, the simultaneous SO_2 and NO removal technology that structure is simple, efficiency height, cost are low is following developing direction, is subject to domestic and international great attention.

And the current electron beam being tending towards industrialization gradually/ammonia method (EBA) is although desulfurization degree and denitration rate can reach more than 80%, but need the electron-beam accelerator and the high-power electron gun that produce high-energy electron, and needing radiological protection facility, rumbatron is expensive, power consumption is high, maintenance workload is big, running cost height. The catalyzer of existing exploitation mostly needs reducing gas, and simultaneously de-except oxynitride and oxysulfide difficulty, active carbon adsorption often needs dry manipulation of regeneration, CuO/ ��-Al₂O₃Not good Deng sulfur poisoning-resistant and the vapour resistant performance of catalyzer, it is easy to inactivation.

Patent of invention CN105032403A discloses a kind of for flue gas low-temperature desulphurization denitration catalyzer and preparation method, it is taking Nitric Acid Modified gac as carrier, taking transition metal manganese and rare earth cerium as active ingredient, loaded catalyst has been prepared by dipping, method that is dry and roasting, 80-220 DEG C of scope, at air speed 2700h^-1, reaction for degree 80 DEG C time desulfurization degree reach 100%, at air speed 5000h^-1, ammonia nitrogen ratio when being 1.2,130 DEG C denitration rate reach more than 90%.Patent of invention CN103691476A discloses a kind of low-temperature synchronous desulphurization denitration catalyzer and preparation method, carry out mixing making by mesoporous SBA-15, nano titanium oxide (Detitanium-ore-type) and various metals oxide compound (Mn, V, Cr, Ce, W, Mo) and ammoniacal liquor and deionized water to expect at the beginning of catalyzer, adding toughener glass fibre, linking agent methacrylic acid-2-carboxylic second ester, tensio-active agent stearic acid and thermo-stabilizer again, to carry out No. two batch mixings shaping, makes porous catalyst after calcining. Being less than at 300 DEG C to react, air speed is 10000h^-1, desulfurization degree reaches more than 95%, and denitration rate reaches more than 92%.

Summary of the invention

It is an object of the invention to overcome existing technique not enough, it is provided that a kind of do not need reducing gas and can the effective catalyst of simultaneous SO_2 and NO removal and its preparation method.

The present invention provides a kind of simultaneous SO_2 and NO removal Catalysts and its preparation method without the need to reducing gas, and described catalyzer is by carrier of ZSM-5 molecular sieve, with CuO, V₂O₅��K₂O��CoO��Ni₂O₃��WO₃For active ingredient, its mass content is respectively 0.5-2.5%, 0.5-2.5%, 0-1.5%, 0-1.5%, 0-1.5%, 0-1.5%.

The technical scheme of the present invention is, with CuO and V₂O₅Be combined into master, with K₂O��CoO��Ni₂O₃��WO₃For auxiliary agent, carry out different combinations, and it is prepared by one or many dipping, method dry, roasting.

The preparation method of this simultaneous SO_2 and NO removal catalyzer is:

Step one, the carrier of catalyzer first filters after flooding 1-3h in the distilled water of 50-70 DEG C, then steams 3-6h, finally roasting 2-5h in 450-650 DEG C of air in 110-130 DEG C.

Step 2, by the mass percent of carrier, take cupric nitrate, Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES, saltpetre, nickelous nitrate, ammonium meta-vanadate and ammonium tungstate, first ammonium meta-vanadate is dissolved in acid distilled water, add cupric nitrate, Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES, saltpetre, nickelous nitrate and ammonium tungstate again, and regulate solution acidic to solution equal one with ammoniacal liquor.

Step 3, joins the carrier equal-volume of step one gained in the solution of step 2 gained, floods 2-5h at 40-60 DEG C, and after filtering, gained solid steams 8-14h at 110-130 DEG C, then in 450-650 DEG C of roasting 4-8h.

For the catalyzer repeatedly flooded, each load all to be repeated above-mentioned dipping, drying and calcination steps and condition, finally this catalyzer obtained.

The catalyzer of preparation of the present invention, it may also be useful to front do not need other gas activation just to have desulphurization denitration active, after activity decrease, can activate by improving temperature.

The catalyzer working conditions of the present invention is: temperature of reaction 300-500 DEG C, air speed 5000-10000h^-1, flue gas can contain oxynitride, oxysulfide, carbonic acid gas, oxygen, steam, nitrogen etc. simultaneously, carry out at ambient pressure.

The catalyzer of the present invention is large granular catalyst, and granularity, at 2-4 millimeter, for fixed-bed reactor, can heat outward and high-temperature gas circulation heating.

Under the above-described reaction conditions, the decreasing ratio of oxynitride can reach more than 60-70% to the catalyzer of the present invention, and the removal of nitrogen oxide rate after its absorption can reach more than 83-95%, and sulfur dioxide removal rate can reach 100%.

The catalyzer of the present invention is for producing after coal combustion in flue gas containing a large amount of SO₂With a kind of catalyzer not needing reducing gas to get final product simultaneous SO_2 and NO removal of NO pollutent exploitation, there is between 300-400 DEG C best simultaneous SO_2 and NO removal effect.

The catalyzer of the present invention has that specific surface area is big, physical strength height, cost are low, activity is high, decreasing ratio height, good stability, the feature such as simple to operate, without the need to using ammonia reduction catalysts, do not need reduction activation can reach the effect of simultaneous SO_2 and NO removal, and there is no ammonia secondary pollution and carbon dioxide greenhouse gas discharge.

Embodiment:

Below in conjunction with specific embodiment, the invention will be further described, but does not form any limitation of the invention.

Embodiment 1:

Taking 0.115g ammonium meta-vanadate and 0.23g oxalic acid is placed in the clean beaker of 100mL, adding distil water (about 20mL) dissolves, then adds 0.19g cupric nitrate, drips and add ammoniacal liquor in this turbid solution, until solution equal one. Taking the nickelous nitrate of 0.124g and the saltpetre of 0.65g more respectively, add wherein, solution still in uniform state, surveys its pH between 6-7, and adding distil water is to 60mL. Finally add the ZSM-5 molecular sieve carrier of 5g ball type, in the water-bath of 50 DEG C, flood 4h. Filter after dipping, solid be placed in crucible, then steam dry 12h prior to 120 DEG C, after in 500 DEG C of roasting 6h. Taking the beaker that 0.124g Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES is placed in 100mL, adding distil water dissolves, and is settled to 60mL, adds wherein by the solid work in-process catalyzer after roasting, floods 4h in 50 DEG C. Filter after dipping, solids be placed in crucible, then steam dry 12h prior to 120 DEG C, after in 500 DEG C of roasting 6h, obtain work in-process catalyzer.

Continue dipping more once by above-mentioned preparation process double finished catalyst, obtain finished product Cu-V-Ni-K-Co/ZSM-5 catalyzer.

Get the catalyzer prepared, join in the fixed-bed micro-reactor of diameter 1.6cm height 15cm, after guaranteeing that device each several part seals, open simulated flue gas cylinder valve, flow is regulated to be 60mL/min through under meter, the temperature being regulated reactor by temperature regulator is 500 DEG C, and after activation 30min, temperature regulating is 350 DEG C and evaluates. O₂When content is between 3.0-5.0%, average the consisting of of flue gas: SO₂1000ppm��NO1100ppm��NO₂55ppm, CO₂14.5-15.5%, balance gas is nitrogen. Evaluation result is in table 1.

Table 1

Obtaining by data shown in table 1, average denitration rate is 83.9%, and average desulfurization degree is 100%, if can reach more than 95% through alkali liquor absorption denitration rate. Denitration rate and desulfurization degree are calculated as follows:

Denitration rate=[(NO+NO₂)_{Before reaction}-(NO+NO₂)_{After reaction}]/(NO+NO₂)_{Before reaction}

Desulfurization degree=[(SO₂)_{Before reaction}-(SO₂)_{After reaction}]/(SO₂)_{Before reaction}

Embodiment 2:

With embodiment one, with same condition and preparation method, by weight 1% impregnation concentration dipping copper and vanadium while of disposable, obtain Cu-V/ZSM-5 catalyzer. This catalyzer forms at reaction unit and the unstripped gas of same embodiment one, under the same reaction conditions, records such as following table 2 result:

Table 2

Embodiment 3:

With embodiment one, with same preparation condition and preparation method, all by weight 1% impregnation concentration dipping copper, vanadium and tungsten while of disposable, obtained Cu-V-W/ZSM-5 catalyzer. This catalyzer at the reaction unit of same embodiment one and unstripped gas composition, under the same reaction conditions, reaction end gas through 5% alkali liquor absorption or after 500 DEG C under Primordial Qi atmosphere activation, reaction at 350 DEG C, records such as following table 3 result:

Table 3

Catalyzer duration of service	Desulfurization degree %	NO(ppm)	NO₂(ppm)	Denitration rate %
					115min (does not absorb and activates)	100	423	21.1	61.55
After absorption	100	128	6.4	88.36
					After absorption	100	190	9.5	82.73
Activation 0.5h, uses 15min	100	67	3.35	93.91
					Activation 0.5h, uses 82min	100	286	14.3	74.00
Activation 1h is fresh	100	130	6.5	88.18
					Activation 1h, uses 30min	100	265	12.9	75.94
Activation 2h, uses 42min	100	87	4.35	92.09
					Activation 2h, uses 113min	100	306	15.3	72.18

Embodiment 4:

With embodiment one, with same preparation condition and preparation method, the while of disposable by weight configuration impregnation concentration be 0.5% nickel, 1% tungsten, the vanadium of 1%, the potassium of 1% and 1% copper, obtained Cu-V-W-Ni-K/ZSM-5 catalyzer. This catalyzer forms at reaction unit and the unstripped gas of same embodiment one, under other same reaction conditions, changes temperature of reaction and evaluates, record such as following table 4 result:

Table 4

Temperature of reaction DEG C	Desulfurization degree %	NO(ppm)	NO₂(ppm)	Denitration rate %
					300	100	265	13.9	75.85
350	100	234	11.7	78.73
					390	100	373	18.6	66.10
430	100	514	25.7	53.27
					500	100	605	30.3	45.05

Embodiment 5:

With preparation condition and the preparation method of embodiment one, first simultaneously by weight configuration impregnation concentration be the nickel of 0.5%, the potassium of 0.5% and 0.5% cobalt, again simultaneously by weight configuration impregnation concentration be the tungsten of 1%, the vanadium of 1% and 1% copper, obtained Cu-V-W-Ni-K-Co/ZSM-5 catalyzer.This catalyzer, under the reaction unit and unstripped gas composition of same embodiment one, under other same reaction conditions, changes temperature of reaction and evaluates, record such as following table 5 result:

Table 5

Temperature of reaction DEG C	Desulfurization degree %	NO(ppm)	NO₂(ppm)	Denitration rate %
					300	100	204	10.9	81.39
370	100	280	14	74.55
					390	100	287	14.3	73.91
440	100	570	28.5	48.18

Claims

1. the simultaneous SO_2 and NO removal catalyzer without the need to reducing gas, it is characterised in that this catalyzer by molded ZSM-5 molecular sieve be carrier, with CuO, K₂O��CoO��Ni₂O₃��V₂O₅��WO₃For active ingredient, its mass content is respectively 0.5-2.5%, 0-1.5%, 0-1.5%, 0-1.5%, 0.5-2.5% and 0-1.5%.

2. catalyzer according to claim 1, it is characterised in that, with CuO and V₂O₅Be combined into master, with K₂O��CoO��Ni₂O₃��WO₃For auxiliary agent, carry out different combinations, and it is prepared by one or many dipping, method dry, roasting.

3. catalyzer according to claim 1, it is characterised in that, starting material used are ZSM-5 molecular sieve (specific surface 300-500m²/ g), cupric nitrate, Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES, saltpetre, nickelous nitrate, ammonium meta-vanadate and ammonium tungstate.

4. catalyzer according to claim 1, it is characterised in that, this catalyzer is applied when not needing reducing gas.

5. according to the requirement of claim 1,2 and 3, the preparation method of this catalyzer, it is characterised in that:

1. after the carrier of catalyzer floods 1-3h in the distilled water of 50-70 DEG C, first filter, then steam 3-6h, finally roasting 2-5h in 450-750 DEG C of air in 110-130 DEG C;

2. the mass percent of carrier is pressed, take cupric nitrate, Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES, saltpetre, nickelous nitrate, ammonium meta-vanadate and ammonium tungstate, first ammonium meta-vanadate is dissolved in acid distilled water, add cupric nitrate, Jing Ti/Bao Pian COBALT NITRATE CRYSTALS/FLAKES, saltpetre, nickelous nitrate and ammonium tungstate again, and regulate solution acidic to solution equal one with ammoniacal liquor;

3. being joined by the carrier equal-volume of step 1. gained in the solution of 2. gained, flood 2-5h at 40-60 DEG C, after filtering, gained solid steams 8-14h at 110-130 DEG C, then in 450-750 DEG C of roasting 4-8h;

4. the catalyzer repeatedly flooded, each load all to be repeated above-mentioned dipping, drying and calcination steps and condition, finally this catalyzer obtained.

6. the catalyzer prepared according to claim 5, it is characterised in that, it may also be useful to front do not need other gas activation just to have desulphurization denitration active, after activity decrease, can activate by improving temperature.

7. this catalyzer prepared to claim 5 according to claim 1 and condition, it is characterised in that, temperature of reaction 300-400 DEG C, air speed is at 5000-10000h^-1, gas group becomes NO:900-1100ppm, SO₂: 1000-1300ppm, CO₂: 2-10%, all the other be nitrogen condition of normal pressure under record removal of nitrogen oxide rate and can reach more than 60-70%, the removal of nitrogen oxide rate after its absorption can reach more than 90%, and sulfur dioxide removal rate can reach 100%.