CN101422734B - Preparation method of copper group catalyst for purifying nitrogen monoxide using propone - Google Patents

Abstract

The invention discloses a preparation method of a copper catalyst for purifying NO by adopting propylene under oxygen-enriched condition, aqueous salvolatile solution is heated, aqueous solution compound of Al(NO3)3, La(NO3)2 and/or ZrOCl2 is dropped into the aqueous salvolatile solution under agitation, and filtered solids are dried and baked, thus obtaining a composite carrier, which is steeped in Cu<2+> solution, parched and baked so as to produce the catalyst. The invention has simplified production steps, easy production technique control and smaller particles of the prepared catalyst, does not need modification by adopting SO4<2-> and has further raised catalytic activity, and the obtained catalyst can be used for the NO purification of tail gases of oil-burning or coal-burning power plants, internal-combustion engines and particularly motor vehicles.

Description

The preparation method of the nitric oxide production Cu-series catalyst of propylene purified treatment

Technical field

The present invention relates to a kind of NO (nitric oxide) is reduced into the manufacture method of the catalyst of nitrogen, more specifically relate to a kind ofly under excess oxygen, adopt NO in the propylene selective reduction fuel exhaust gas, thus the manufacture method of the nitric oxide production Cu-series catalyst of purified treatment.

Background technology

Along with the growth of industrial expansions such as thermal power generation and motor vehicle number, exhaust gas discharging is serious day by day, the nitrogen oxide (NO of discharging _x) increase day by day.In the nitrogen oxide of discharging, NO accounts for more than 90%.NO both can cause serious environmental to pollute, and also can directly endanger health of people.Simultaneously, for alleviating global energy crisis, the design and use of energy-saving poor burn engine develop day by day, though poor combustion can improve the efficiency of combustion of fuel, also cause the NO discharge capacity to rise significantly.Therefore, how effectively to eliminate the problem that NO has become domestic and international great attention.

It is one of effective ways of eliminating NO that hydro carbons is selected Reduction of NO, and the catalyst of development hydrocarbon selective reductive NO also just becomes the focus of present research.Wherein, adopt Al ₂O ₃The catalyst of loaded Cu is owing to have lower, the good hydrothermal stability of optimum activity temperature, and advantage such as cheap and easy to get, is the catalyst that causes that the researcher favors always, but the Cu/Al of bibliographical information in recent years ₂O ₃Activity of such catalysts is still lower, is difficult to make the NO conversion ratio to bring up to 50%.Find in inventor's research, adopt the synthetic La that prepared of hydro-thermal method ₂O ₃-ZrO ₂-Al ₂O ₃Composite carrier load Cu ²⁺, adopt SO again ₄ ^2-Carry out modification, prepared catalyst can make the conversion ratio of NO reach 84.33% under 275 ℃.The applicant has proposed patent application to China Intellectual Property Office for this reason, has obtained mandate on September 12nd, 2007, and the patent No. is ZL200510037084.7.But this catalyst adopts hydro-thermal method and SO ₄ ^2-Modification is prepared, and method is more loaded down with trivial details, and energy consumption is bigger, and the inventor also thinks in addition, La ₂O ₃-ZrO ₂-Al ₂O ₃Composite carrier load Cu ²⁺Activity of such catalysts also has the possibility that further improves.

Summary of the invention

It is simple to the purpose of this invention is to provide a kind of technology, has the more selecting reduction of NO by propylene of high catalytic activity, thus the preparation method of the Cu-series catalyst of purified treatment NO.

Cu-series catalyst of the present invention is by complex carrier and the active component Cu that loads on the complex carrier ²⁺Form.Complex carrier is by weight percentage by 84～96% Al ₂O ₃, 4～16% ZrO ₂And/or La ₂O ₃Form, comprise La ₂O ₃-ZrO ₂-Al ₂O ₃Complex carrier, La ₂O ₃-Al ₂O ₃Complex carrier, perhaps ZrO ₂-Al ₂O ₃Complex carrier.Active component Cu ²⁺With complex carrier weight is that the content of benchmark is 1～5%.

Above-mentioned complex carrier is La preferably ₂O ₃-ZrO ₂-Al ₂O ₃Complex carrier, wherein Al ₂O ₃Weight percentage be 90～96%, La ₂O ₃Weight percentage be 1～3%, ZrO ₂Weight percentage be 3～7%.

Above-mentioned active component Cu ²⁺Content be 2～4% of complex carrier weight.

Preparation method of the present invention in turn includes the following steps:

(1) preparation complex carrier: with concentration is that the ammonium carbonate solution of 0.01～1.0mol/L is heated under 30～40 ℃ of stirrings, splashes into Al (NO with the speed of 0.2～5ml/min ₃) ₃, La (NO ₃) ₂And/or ZrOCl ₂Aqueous solution composition, reaction back room temperature ageing 3～30 hours, the solids after the filtration in air atmosphere, 400～900 ℃ of roastings 1～3 hour, obtains complex carrier 100～150 ℃ of dryings 1～10 hour;

(2) make catalyst: will make complex carrier Cu ²⁺Solution impregnation 12～24 hours in 300～700 ℃ of roastings 1～5 hour, makes catalyst after 100～180 ℃ of oven dry.

In the above-mentioned aqueous solution composition, Al (NO ₃) ₃Concentration be preferably 0.05～1.0mol/L, La (NO ₃) ₂And/or ZrOCl ₂Concentration then by Al in the described complex carrier ₂O ₃, La ₂O ₃And/or ZrO ₂Percentage by weight, with Al (NO ₃) ₃Concentration be benchmark, press Al ³⁺, La ³⁺And/or Zr ²⁺Be completed into Al ₂O ₃, La ₂O ₃And/or ZrO ₂, the La (NO that calculates ₃) ₂And/or ZrOCl ₂Concentration.

Above-mentioned Cu ²⁺Solution is preferably Cu (NO ₃) ₂, CuCl ₂Or CuSO ₄, be more preferably the Cu (NO that adopts 0.1～2.0mol/L ₃) ₂Solution.

In the above-mentioned steps (1), the aqueous solution composition speed of splashing into is preferably 0.8～1.2ml/min.

In the above-mentioned steps (2), bake out temperature is 120～140 ℃, and the time is 2～8 hours, with the heating rate of 4～6 ℃ of per minutes, temperature is elevated to 450～550 ℃ of roastings 1～3 hour then.

The present invention adopts coprecipitation to prepare complex carrier production stage is simplified, and production technology is more easy to control, and the catalyst granules that makes diminishes, and does not need to adopt SO ₄ ^2-Modification, catalytic activity also further improve, and under the situation that does not have steam, the conversion ratio of NO reached as high as 88.9% when reaction temperature was 300 ℃; Under the situation that has 10% steam to exist in the reaction mixture gas, the conversion ratio of NO still reaches about 80% in the time of 300 ℃, show that the catalyst that the present invention obtains has fabulous catalytic activity and humidity resistance, catalyst of the present invention can be used for fuel oil or coal-burning power plant's tail gas, the exhaust gases of internal combustion engines purified treatment of NO in the motor-vehicle tail-gas particularly.

The specific embodiment

Activity of such catalysts of the present invention and study on the stability carry out in fixed bed continuous-flow reaction system.Reaction unit is made with diameter 8mm quartz ampoule, and reaction bed temperature is controlled by thermocouple.Reacted product adopts GC9790 gas chromatograph and online each components contents of detection gaseous mixture of FGA-4100 five component automobile exhaust analyzers via six-way valve.Packed column is 5A molecular sieve and Porapak-N.The former is used for detecting N ₂, CO, O ₂And NO, the latter is used for detecting C ₃H ₆, CO ₂And N ₂O.Initial concentration and N with NO ₂Generation be calculated as follows the conversion ratio (C of NO _NO), with the activity of the conversion ratio evaluate catalysts of NO.

$C_{\mathrm{NO}}=\frac{2\left[N_2\right]}{{\left[\mathrm{NO}\right]}_0}\&times;100\%$

Reaction condition: temperature 200-600 ℃, air speed 20000h ^-1, catalyst particle size 60-80 order, loading amount are 0.3g.

Be used to check the reactor feed gas of NO conversion ratio to adopt the gaseous mixture of modulating, NO and O in the gaseous mixture ₂Concentration preferably and fuel oil or coal-burning power plant's tail gas, or NO and O in the motor-vehicle tail-gas ₂Concentration close so that obtain the best serviceability temperature of catalyst.Each component of gaseous mixture that the present invention adopts controls separately with mass flowmenter that flow mixes to blender, controls the composed as follows of gaseous mixture: NO2000ppm; C ₃H ₆1200ppm; O ₂2.0%, do carrier gas with He.When investigation steam influenced catalytic activity, adding volume content was 10% steam, and by adjusting the He throughput, it is constant to keep air speed and other each reactive component concentration.

Example 1:Cu/La ₂O ₃-Al ₂O ₃The catalytic effect of catalyst

With concentration is that the ammonium carbonate solution of 0.1mol/L places 35 ℃ water-bath successively to stir, and splashes into the speed of 1ml/min to contain promising 0.1mol/L Al (NO ₃) ₃And 0.0006386mol/LLa (NO ₃) ₂Aqueous solution composition, reaction back is in room temperature ageing 12 hours, the solids after the filtration in air atmosphere, 700 ℃ of roastings 2 hours, obtains La in 130 ℃ of dryings 5 hours ₂O ₃Weight content is 2% La ₂O ₃-Al ₂O ₃Complex carrier;

With above-mentioned La ₂O ₃-Al ₂O ₃Complex carrier Cu (the NO of 0.62mol/L ₃) ₂Solution incipient impregnation 12 hours, 130 ℃ of dryings 5 hours in air atmosphere, 500 ℃ of roastings 2 hours, make and contain Cu ²⁺Amount is 3% Cu/La of complex carrier weight ₂O ₃-Al ₂O ₃Catalyst.

Above-mentioned catalyst is 100～600 ℃ in reaction temperature, and air speed is 20000h ^-1, the catalyst loading amount is to react under the condition of 0.3g.In helium atmosphere, heat up before the reaction, heating rate is 10 ℃ of per minutes, and under 500 ℃ of temperature, catalyst was carried out activation processing 2 hours with hydrogen, switch to helium then, naturally cooling, when temperature is reduced to 90 ℃, switch unstripped gas and react NO conversion data such as following table under each reaction temperature:

Reaction temperature (℃)	NO conversion ratio (%)
		200	10.2
225	29.2
		250	49.5
275	72.7
		300	82.7
325	74.5
		350	64.1
400	51.9
		450	40.1
500	30.3
		550	21.3
600	15.2

As can be seen, when reaction temperature was 300 ℃, the conversion ratio of NO reached maximum, was 82.7%.

Example 2:Cu/ZrO ₂-Al ₂O ₃The catalytic effect of catalyst

With concentration is that the ammonium carbonate solution of 0.1mol/L places 35 ℃ water-bath successively to stir, and splashing into content with the speed of 1ml/min is 0.1mol/L Al (NO ₃) ₃With 0.00218mol/L ZrOCl ₂Aqueous solution composition, reaction back is in room temperature ageing 12 hours, the solids after the filtration in air atmosphere, 700 ℃ of roastings 2 hours, obtains ZrO in 130 ℃ of dryings 5 hours ₂Weight content is 5% ZrO ₂-Al ₂O ₃Complex carrier;

With ZrO ₂-Al ₂O ₃Complex carrier Cu (the NO of 0.62mol/L ₃) ₂Solution incipient impregnation 12 hours, 130 ℃ of dryings 5 hours in air atmosphere, 500 ℃ of roastings 2 hours, make and contain Cu ²⁺Amount is 3% Cu/ZrO of complex carrier weight ₂-Al ₂O ₃Catalyst.

The reaction condition of selecting reduction of NO by propylene is with example 1, the conversion ratio of NO such as following table under each reaction temperature:

Reaction temperature (℃)	NO conversion ratio (%)
		200	9.2
225	30.5
		250	50.5
275	76.2
		300	84.1
325	73.2
		350	63.2
400	51.6
		450	40.8
500	31.7
		550	24.2
600	17.9

As can be seen, when reaction temperature was 300 ℃, the conversion ratio of NO reached maximum, was 84.1%.

Example 3:Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃The catalytic effect of catalyst

With concentration is that the ammonium carbonate solution of 0.1mol/L places 35 ℃ water-bath successively to stir, and splashes into the Al (NO that content is 0.1mol/L with the speed of 1ml/min ₃) ₃, 0.0006732mol/L La (NO ₃) ₂And the ZrOCl of 0.00223mol/L ₂Aqueous solution composition, reaction back is in room temperature ageing 12 hours, the solids after the filtration in air atmosphere, 700 ℃ of roastings 2 hours, obtains ZrO in 130 ℃ of dryings 5 hours ₂Weight content be 5%, La ₂O ₃Weight content be 2% ZrO ₂-La ₂O ₃-Al ₂O ₃Complex carrier;

With ZrO ₂-La ₂O ₃-Al ₂O ₃Complex carrier Cu (the NO of 0.62mol/L ₃) ₂Solution incipient impregnation 12 hours, 130 ℃ of dryings 5 hours in air atmosphere, 500 ℃ of roastings 2 hours, make and contain Cu ²⁺Amount is 3% Cu/ZrO of complex carrier weight ₂-La ₂O ₃-Al ₂O ₃Catalyst.

The reaction condition of selecting reduction of NO by propylene is with example 1, the conversion ratio of NO such as following table under each reaction temperature:

Reaction temperature (℃)	NO conversion ratio (%)
		200	11.9

225	34.7
		250	54.9
275	77.4
		300	88.9
325	78.3
		350	67.4
400	53.3
		450	42.3
500	32.3
		550	25.3
600	19.2

As can be seen, when reaction temperature was 300 ℃, the conversion ratio of NO reached maximum, was 88.9%.

Example 4:Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃The catalytic effect of catalyst in the presence of steam

The Cu/ZrO of the method preparation of example 3 ₂-La ₂O ₃-Al ₂O ₃Catalyst is 200～600 ℃ in reaction temperature, and air speed is 20000h ^-1, catalyst amount is 0.3g, contains in the reaction mixture gas under 10% water vapor conditions to react.In helium atmosphere, heat up before the reaction, heating rate is 10 ℃ of per minutes, and under 500 ℃ of temperature, catalyst was carried out activation processing 2 hours with hydrogen, then switch to helium, naturally cooling, when temperature is reduced to 90 ℃, switch unstripped gas and react the conversion ratio of NO such as following table under each reaction temperature:

Reaction temperature (℃)	NO conversion ratio (%)
		200	8.2
225	30.1
		250	42.1
275	60.2
		300	74.2
325	79.9

350	62.3
		400	51.2
450	39.3
		500	30.2
550	22.6
		600	15.2

As can be seen, Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Catalyst has good humidity resistance, and the maximum conversion of NO has only descended 9.0%.

Example 5: different Cu ²⁺The Cu/ZrO of load capacity ₂-La ₂O ₃-Al ₂O ₃Catalytic effect

Press example 3 preparation Catalysts Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Method, adopting concentration is the Cu (NO of 0.21mol/L and 1.03mol/L ₃) ₂Solution incipient impregnation ZrO ₂-La ₂O ₃-Al ₂O ₃Complex carrier obtains Cu ²⁺Load capacity be 1% and 5% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Catalyst, and with the same reaction condition of example 4 under, measure its catalytic activity, the conversion ratio of NO such as following table under each reaction temperature to the selecting reduction of NO by propylene reaction:

As can be seen, Cu ²⁺Load capacity is 1% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃When the catalyst optimal reaction temperature was 325 ℃, the conversion ratio maximum of NO was 83.4%; Cu ²⁺Load capacity is 5% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃When the catalyst optimal reaction temperature was 300 ℃, the conversion ratio maximum of NO was 84.7%.

Example 6: different ZrO ₂The Cu/ZrO of content ₂-La ₂O ₃-Al ₂O ₃Catalytic effect

Press example 3 preparation Catalysts Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Method, change ZrOCl in the aqueous solution composition ₂Content be 0.00141mol/L and 0.00335mol/L, Al (NO ₃) ₃And La (NO ₃) ₂Content identical, obtain ZrO ₂Content be 3% and 7% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Catalyst, and with the same reaction condition of example 3 under, measure its catalytic activity, the conversion ratio of NO such as following table under each reaction temperature to the selecting reduction of NO by propylene reaction:

As can be seen, when reaction temperature was 300 ℃, the conversion ratio of NO reached maximum, was respectively 83.3% and 84.9%.

Example 7: Different L a ₂O ₃The Cu/ZrO of content ₂-La ₂O ₃-Al ₂O ₃Catalytic effect

Press example 3 preparation Catalysts Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Method, change La (NO in the aqueous solution composition ₃) ₂Content be 0.0010862mol/L and 0.0033256mol/L, Al (NO ₃) ₃And ZrOCl ₂Content identical, obtain La ₂O ₃Content be 1% and 3% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃Catalyst, and with the same reaction condition of example 3 under, measure its catalytic activity, conversion ratio such as the following table of NO under each reaction temperature to the selecting reduction of NO by propylene conversion reaction:

As can be seen, La ₂O ₃Content is 1% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃When the catalyst optimal reaction temperature was 300 ℃, the conversion ratio maximum of NO was 82.6%; La ₂O ₃Content is 3% Cu/ZrO ₂-La ₂O ₃-Al ₂O ₃When the catalyst optimal reaction temperature was 275 ℃, the conversion ratio maximum of NO was 85.8%.

Claims (7)

1. the preparation method of the nitric oxide production Cu-series catalyst of propylene purified treatment,

This catalyst is the active component Cu on complex carrier by complex carrier and appendix ²⁺Form; Described complex carrier is by weight percentage by 84～96% Al ₂O ₃, 4～16% ZrO ₂And/or La ₂O ₃Form; Described active component Cu ²⁺With complex carrier weight is that the content of benchmark is 1～5%;

It is characterized in that, in turn include the following steps:

(1) preparation complex carrier: with concentration is that the ammonium carbonate solution of 0.01～1.0mol/L is heated under 30～40 ℃ of stirrings, splashes into Al (NO with the speed of 0.2～5ml/min ₃) ₃, La (NO ₃) ₂And/or ZrOCl ₂Aqueous solution composition, reaction back room temperature ageing 3～30 hours, the solids after the filtration in air atmosphere, 400～900 ℃ of roastings 1～3 hour, obtains complex carrier 100～150 ℃ of dryings 1～10 hour;

In the described aqueous solution composition, Al (NO ₃) ₃Concentration be 0.05～1mol/L, La (NO ₃) ₂And/or ZrOCl ₂Concentration then by Al in the described complex carrier ₂O ₃, La ₂O ₃And/or ZrO ₂Percentage by weight, with Al (NO ₃) ₃Concentration be benchmark, press Al ³⁺, La ³⁺And/or Zr ²⁺Be completed into Al ₂O ₃, La ₂O ₃And/or ZrO ₂, the La (NO that calculates ₃) ₂And/or ZrOCl ₂Concentration;

(2) make catalyst: will make complex carrier Cu ²⁺Aqueous solution dipping 12～24 hours in 300～700 ℃ of roastings 1～5 hour, makes catalyst after 100～180 ℃ of oven dry.

2. according to the described preparation method of claim 1, it is characterized in that: described Cu ²⁺The aqueous solution is Cu (NO ₃) ₂The aqueous solution, CuCl ₂The aqueous solution or CuSO ₄The aqueous solution.

3. according to the described preparation method of claim 2, it is characterized in that: described Cu ²⁺The aqueous solution is the Cu (NO of 0.1～2.0mol/L ₃) ₂Solution.

4. according to the described preparation method of claim 1, it is characterized in that: in the described step (1), the aqueous solution composition speed of splashing into is 0.8～1.2ml/min.

5. according to the described preparation method of claim 1, it is characterized in that: in the described step (2), bake out temperature is 120～140 ℃, and the time is 2～8 hours, with the heating rate of 4～6 ℃ of per minutes, temperature is elevated to 450～550 ℃ of roastings 1～3 hour then.

6. according to the described preparation method of claim 1, it is characterized in that: described complex carrier is La ₂O ₃-ZrO ₂-Al ₂O ₃Complex carrier, wherein Al ₂O ₃Weight percentage be 90～96%, La ₂O ₃Weight percentage be 1～3%, ZrO ₂Weight percentage be 3～7%.

7. according to the described preparation method of claim 1, it is characterized in that: described active component Cu ²⁺Content be 2～4% of complex carrier weight.