CN101518736A - Desulphurization and denitration catalyst and preparation method thereof - Google Patents

Abstract

The invention discloses a desulphurization and denitration catalyst. The catalyst comprises the following components by mass percentage: 4 to 18 percent of CuO, 80 to 95 percent of gamma-Al2O3, and 1 to 2 percent of promoter. A method for preparing the catalyst comprises the following steps: (1) adding aluminum isopropoxide into distilled water, stirring the mixture, adding a nitric acid solution into the mixture dropwise, and carrying out the evaporation in the air to obtain a boehmite sol; (2) adding the promoter into a copper nitrate solution, then adding the mixture into the boehmite sol, then adding the nitric acid solution dropwise, stirring the mixed solution for ageing, and aggregating the mixed solution into a semi-gel; and (3) adding the semi-gel dropwise into a gel pool containing ammonia water and liquid paraffin through a dropper, and obtaining the catalyst after ageing, drying and baking. The prepared catalyst can be used for synchronous desulphurization and denitration, and can be regenerated and used cyclically with low raw material cost. As the byproducts can be reutilized, the catalyst brings about no secondary pollution.

Description

A kind of desulphurization denitration Catalysts and its preparation method

Technical field

The present invention relates to the air contaminant treatment field, particularly relate to a kind of SO in the flue gas that removes simultaneously ₂And NO _XThe catalyst of gas and preparation technology thereof, wherein NO _XRepresent the various forms of nitrogen oxide.

Background technology

Industries such as the energy, chemical industry, metallurgy, traffic use in the flue gas that fossil fuel (coal, oil, natural gas etc.) discharged and contain a large amount of SO ₂And NO _XGas.Along with sending out fast of Chinese national economy opened SO ₂And NO _XThe gas purging amount constantly increases, and atmospheric environment is caused severe contamination, and environmental problem has become the key issue that influences the Chinese national economy sustainable development.Therefore, under situation with limited economic strength, the pollution prevention technique of greatly developing low expense is the task of top priority.The desulphurization denitration technology has huge advantage on economy simultaneously, is a smoke gas treatment technology that tallies with the national condition, and bright development prospect is arranged.

In recent years the practical experience of countries in the world shows, the stack gas cleaning technology is coal-burning power plant's control SO ₂And NO _XThe effective way of discharging.Traditional independent flue gas desulfurization, denitration technology investment and operating cost are very high, if two technology are used simultaneously, even developed country also is difficult to bear fully.Therefore have compact conformation, the desulphurization denitration technology is subjected to increasing attention in the time of advantages such as low expense.At present, common flue gas desulfurization and denitrification technology mainly contains Fuel and Energy Abstracts, 1997,38 (3): 189, the electronic beam method of 97/02388 report, FuelandEnergyAbstracts, 1998,39 (3): 216,98/02396 and Fuel, 1997,76 (6): the activated carbon method of 549-560 report, CuO/ γ-Al2O3 method that Ind.Eng.Chem.Res.2000,39:3868-3874 report for work.Although electronic beam method has been realized industrialization, because its operating cost height is difficult to large-scale promotion at home, and existing catalyst (comprises active carbon and CuO/ γ-Al ₂O ₃), the industrialization because the problem that exists at aspects such as Sulfur capacity, the wear-resisting property of catalyst is unrealized so far.Based on this, be necessary to research and develop a kind of cost is low, efficient is high, sulfur capacity is big, wearability is high catalyst and new preparation process thereof to satisfy the commercial Application demand.

Summary of the invention

The object of the present invention is to provide a kind of desulphurization denitration catalyst, cost of material is low, and the denitrification efficiency height can regeneration cycle use the recyclable utilization of byproduct, non-secondary pollution.

Another object of the present invention is to provide a kind of method that is used to prepare above-mentioned desulphurization denitration catalyst, adopt the catalyst sulfur capacity of this method preparation big, wear-resistant, can regeneration cycle use the recyclable utilization of byproduct, non-secondary pollution.

A kind of desulphurization denitration catalyst comprises 4～18%CuO according to mass percent, 80～95% γ-Al ₂O ₃, 1～2% co-catalyst.

A kind of method for preparing the described catalyst of claim 1 may further comprise the steps:

Step 1 adds aluminium isopropoxide in 70～90 ℃ the distilled water, stirs simultaneously in the adition process until the liquid suspension that is white in color, and splashes into salpeter solution then and becomes colourless sticking shape liquid until suspension, to sky evaporation 1～3 hour, makes boehmite sol;

Step 2 adds co-catalyst in copper nitrate solution, in the boehmite sol that its adding is made, splash into salpeter solution more then, splashes into to stir simultaneously until in the pasty state, aging 10～60 minutes, is gathered into semigel;

Step 3 adopts dropper the semigel that makes to be splashed in the gel pond that includes ammoniacal liquor and atoleine, makes wet gel in aging 1～2 hour, and with the wet gel oven dry, roasting obtained catalyst in 4～6 hours in 300～600 ℃ of temperature ranges again.

Described co-catalyst is Na ₂O, MnO ₂, CeO ₂And V ₂O ₅In a kind of or its combination.

Technique effect of the present invention is embodied in:

(1) the present invention adopts aluminium isopropoxide, copper nitrate and co-catalyst as raw material, and these raw material sources are extensive, obtain easily, and cost is low.

(2) Zhi Bei catalyst activity is strong, and sulfur capacity is big, and specific area is big, therefore has desulfurization off sulfide effect preferably, and in the simulated flue gas experiment, denitrification efficiency all can reach more than 90%.

(3) catalyst is stable, and is wear-resisting, can keep certain activity in a long time.

(4) catalyst is a dry state, does not need the aqueous solution during use, has reduced the water consumption.

(5) in the course of reaction, catalyst can promote NO on the one hand _XWith NH ₃Reaction absorbs SO on the other hand to play denitration ₂Generate copper sulphate and reach the desulfurization purpose.After the desulfurization, will contain a large amount of SO ₂Catalyst transfer to regenerative system and regenerate, under 450～800 ℃ of temperature, carry out following reaction: 2CuSO ₄→ 2CuO+SO ₃+ SO ₂+ 1/2O ₂Catalyst after the regeneration is transferred to reactor with transmission mechanism, continues to participate in desulfurization and denitrification reaction.The SO that regenerative process produces ₂, SO ₃Mist is sent into the byproduct for treatment part, and through catalysis, conversion and absorption, acquisition concentration is the concentrated sulfuric acid byproduct more than 92%, to reach the purpose of recycling, minimizing secondary pollution.

The specific embodiment

Enumerate embodiment below:

Embodiment 1:

Measure the distilled water of 100mL, place 75 ℃ of oil baths to be incubated, the aluminium isopropoxide powder that takes by weighing 20g then slowly adds wherein, stir simultaneously in the adition process until the liquid suspension that is white in color, the salpeter solution that splashes into 1mol/L afterwards becomes colourless sticking shape liquid until suspension, to sky evaporation 1 hour, make boehmite sol.Measure the 1mol/L copper nitrate solution of 2.7mL, and to the Na that wherein adds 0.086g ₂O and CeO ₂Powder adds the boehmite sol that makes with mixed liquor, splashes into the salpeter solution of 1mol/L, stirs simultaneously until in the pasty state, aging 20 minutes, is gathered into semigel; Adopt dropper to splash into the semigel that makes in the gel pond that includes ammoniacal liquor and atoleine with the 3mm diameter, made wet gel in aging 1 hour, the vacuum drying chamber of wet gel being put into 40 ℃ is dried, obtained catalyst in 5 hours at 350 ℃ of roasting temperatures again, wherein make catalyst and consist of 5% CuO, 93% γ-Al ₂O ₃. and 2% Na ₂O, CeO ₂Being characterized as of catalyst: specific area 269.45m ²/ g, pore volume 0.466cm ³/ g, the aperture

Embodiment 2

Measure the distilled water of 100mL, place 80 ℃ of oil baths to be incubated, the aluminium isopropoxide powder that takes by weighing 15g then slowly adds wherein, stir simultaneously in the adition process until the liquid suspension that is white in color, the salpeter solution that splashes into 1mol/L afterwards becomes colourless sticking shape liquid until suspension, to sky evaporation 2 hours, make boehmite sol.Measure the 1mol/L copper nitrate solution of 5.3mL, and to the MnO that wherein adds 0.052g ₂And CeO ₂Powder adds the boehmite sol that makes with mixed liquor, splashes into the salpeter solution of 1mol/L, stirs simultaneously until in the pasty state, aging 30 minutes, is gathered into semigel; Adopt dropper to splash into the semigel that makes in the gel pond that includes ammoniacal liquor and atoleine with the 4mm diameter, made wet gel in aging 2 hours, the vacuum drying chamber of wet gel being put into 60 ℃ is dried, obtained catalyst in 4 hours at 400 ℃ of roasting temperatures again, wherein make catalyst and consist of 12% CuO, 86.5% γ-Al ₂O ₃And account for the MnO of the above two gross weights 1.5% ₂, CeO ₂Being characterized as of catalyst: specific area 237.96m2/g, pore volume 0.442cm3/g, aperture

Embodiment 3

Measure the distilled water of 100mL, place 85 ℃ of oil baths to be incubated, the aluminium isopropoxide powder that takes by weighing 10g then slowly adds wherein, stir simultaneously in the adition process until the liquid suspension that is white in color, the salpeter solution that splashes into 1mol/L afterwards becomes colourless sticking shape liquid until suspension, to sky evaporation 1 hour, make boehmite sol.Measure the 1mol/L copper nitrate solution of 4.5mL, and to the V that wherein adds 0.040g ₂O ₅Powder adds the boehmite sol that makes with mixed liquor, splashes into the salpeter solution of 1mol/L, stirs simultaneously until in the pasty state, aging 50 minutes, is gathered into semigel; Adopt dropper to splash into the semigel that makes in the gel pond that includes ammoniacal liquor and atoleine with the 5mm diameter, made wet gel in aging 1 hour, the vacuum drying chamber of wet gel being put into 80 ℃ is dried, obtained catalyst in 6 hours at 450 ℃ of roasting temperatures again, wherein make catalyst and consist of 15% CuO, 84% γ-Al ₂O ₃And account for the V of the above two gross weights 1% ₂O ₅Being characterized as of catalyst: specific area 213.62m2/g, pore volume 0.410cm3/g, aperture

With the chamber small-sized heating furnace simulated flue gas experiment that experimentizes of above-mentioned desulphurization denitration catalyst, the technology and equipment of " regenerable metal oxide desulfur technology and the system " that employing is applied for simultaneously by the applicant (number of patent application is 01133521.1), under normal pressure, operating temperature is the SO that feeds 2500ppm under 400 ℃ the condition in the experiment ₂, the NO of 750ppm, and with N ₂As balance gas, press NH ₃/ NO mol ratio 1～1.2 sprays into NH3 as reducing agent, carries out the while desulphurization denitration.Adopt flue gas analyzer (KM900) and portable infrared radiation detection apparatus (GASMET FT-IR Dx4000) that the smoke components before and after the desulphurization denitration is measured.Desulfurization and denitrification reaction device and regeneration reactor all adopt electrical heating tubular type stove, to keep stable reaction temperature.Experimental result shows:

(1) at NH ₃/ NO mol ratio be 1.0,1.1 and 1.2 3 kind of simulated flue gas situation under, experience the desulphurization denitration and the regeneration tests in 12 cycles respectively, denitrification efficiency still can maintain more than 90%;

(2) specific surface is measured and is shown that the specific surface area of catalyst behind the desulphurization denitration reduces (reducing 8～10% approximately) to some extent than fresh catalyst, and through after the regeneration, specific area and pore volume are restored substantially;

(3) the renewable performance of catalyst is good, can be recycling.

(4) SO in the regeneration gas ₂Concentration can reach 6% (volume ratio), be convenient to byproduct processing and utilizing in addition, thereby avoid secondary pollution.

(5) adopt this desulphurization denitration catalyst, can reach industrial application requirements.

Claims (4)

1, a kind of desulphurization denitration catalyst comprises 4～18%CuO according to mass percent, 80～95% γ-Al ₂O ₃, 1～2% co-catalyst.

2, desulphurization denitration catalyst according to claim 1 is characterized in that, described co-catalyst is Na ₂O, MnO ₂, CeO ₂And V ₂O ₅In a kind of or its combination.

3, a kind of method for preparing the described catalyst of claim 1 may further comprise the steps:

Step 1 adds aluminium isopropoxide in 70～90 ℃ the distilled water, stirs simultaneously in the adition process until the liquid suspension that is white in color, and splashes into salpeter solution then and becomes colourless sticking shape liquid until suspension, to sky evaporation 1～3 hour, makes boehmite sol;

Step 2 adds co-catalyst in copper nitrate solution, in the boehmite sol that its adding is made, splash into salpeter solution more then, splashes into to stir simultaneously until in the pasty state, aging 10～60 minutes, is gathered into semigel;

Step 3 adopts dropper the semigel that makes to be splashed in the gel pond that includes ammoniacal liquor and atoleine, makes wet gel in aging 1～2 hour, and with the wet gel oven dry, roasting obtained catalyst in 4～6 hours in 300～600 ℃ of temperature ranges again.

4, method for preparing catalyst according to claim 3 is characterized in that, described co-catalyst is Na ₂O, MnO ₂, CeO ₂And V ₂O ₅In a kind of or its combination.