CN103157480B

CN103157480B - Vanadium oxide/iron oxide denitration catalyst, preparation method and application thereof

Info

Publication number: CN103157480B
Application number: CN201310042930.9A
Authority: CN
Inventors: 张萍; 陈天虎; 邹雪华; 陈冬; 刘海波
Original assignee: Hefei University of Technology
Current assignee: Hefei University of Technology
Priority date: 2013-02-04
Filing date: 2013-02-04
Publication date: 2015-02-18
Anticipated expiration: 2033-02-04
Also published as: CN103157480A

Abstract

The invention discloses a vanadium oxide/ iron oxide denitration catalyst, a preparation method of the vanadium oxide/ iron oxide denitration catalyst and application of the vanadium oxide/ iron oxide denitration catalyst. The catalyst is characterized in that the surface of iron oxide is immobilized with vanadium oxide nanometer particles, and the iron oxide cooperates with the nanometer vanadium oxide to catalyze ammonia to conduct reduction and denitration. The quality percentage of vanadium in the catalyst is 0.1-10%. The preparation method includes that after being measured with an oxalic acid solution of metavanadate, natural goethite particles or composite goethite powder which is prepared in a smashing mode is mixed with the oxalic acid solution of the metavanadate, and catalyst particle materials or powder is obtained through processes of stirring, aging, drying, and hot treating. The catalyst is used as a particle-shaped static bed or is used by being coated on other multi-hole structural materials. The vanadium oxide/ iron oxide denitration catalyst has high activity of reaction of catalyzing the ammonia to conduct the reduction and the denitration within the temperature range of 150-450 DEG C.

Description

A kind of vanadium oxide/iron oxide denitrating catalyst and its preparation method and application

Technical field

The invention belongs to Air Pollution Control Engineering field, especially for denitrifying catalyst with selective catalytic reduction and preparation method thereof.

Background technology

All types of industries kiln and the motor vehicles etc. such as thermal power plant, sintering plant, cement kiln, produce a large amount of NOx in high-temp combustion process.Discharged nitrous oxides not only causes acid rain, also can cause the Regional Environmental Pollution such as photochemical fog and depletion of the ozone layer problem.The technology reducing nitrogen oxides in effluent now mainly contains two classes: the first kind is Combustion Process Control, namely improves combustion system, reduces the generation (comprising low oxygen combustion technology, multi-section-combustion technology etc.) of nitrogen oxide in combustion; Equations of The Second Kind is end treatment, i.e. denitrating flue gas, comprises absorption process, absorption method, non-selective catalytic reduction (SNCR) and SCR (SCR) etc.

The research of SCR denitration receives great concern in recent years.Know net literature retrieval according to China, since two thousand deliver about the Chinese Papers of denitration is up to 1930 sections.Web of Science searches for as descriptor with Selective Catalytic Reduction and NOx, since two thousand delivers relevant catalytic-reduction denitrified paper up to 1384 sections.Up to now, Chinese invention patent application 153 is disclosed.Show that denitrating catalyst is the hot fields of research both at home and abroad always.These denitrating catalysts, from mainly TiO carrier ₂, Al ₂o ₃, active carbon, clay mineral etc., catalytic active component is VO mainly _x, MnO _x, CeO ₂, SnO ₂, in some catalyst, also add auxiliary catalysis component.

Based on V ₂o ₅/ TiO ₂the SCR technology of catalyst has higher denitration efficiency with it and abroad Flue Gas Denitrification Engineering obtains applying more widely, and Some Domestic power plant has introduced this technology and carried out denitrating flue gas.SCR method be using ammonia or urea as reducing agent under catalyst action by NOx catalytic reduction, ammonia can be reacted and generate N by the NOx selectively and in flue gas ₂and H ₂o.

Catalyst V ₂o ₅/ TiO ₂, there is the advantages such as denitration efficiency is high, good stability, add auxiliary agent WO simultaneously ₃its heat endurance can be improved.V ₂o ₅/ TiO ₂denitrating catalyst weak point is: one is that catalysis preparation cost is higher; Two is that catalyst preparation conditions is comparatively strictly wayward; Three is that operating temperature is higher 350 ~ 400 DEG C, and controls strict, is not suitable for the actual conditions that temperature after the existing means of flue gas desulfurization of power plant of China, dedusting is on the low side.

Exploitation low temperature catalyst can make reaction at a lower temperature (about 200 DEG C) carry out, this not only can reduce energy consumption of reaction, reduce costs; It is also conceivable to take SCR device to be placed on ESP(electric precipitation) reduce afterwards or get rid of SO completely ₂on the impact of catalyst.The low temperature SCR denitration catalyst mentioned in domestic and foreign literature is the MnO for preparing of infusion process mainly _x/ TiO ₂, MnO _x/ AC, MnO _x/ Al ₂o ₃, MnO _x, MnO _x/ attapulgite, has higher activity and the activity influence of steam to catalyst is less, but SO in flue gas ₂can produce larger side effect to reactivity, although manganese-based catalyst has the high feature of low temperature active, easily inactivation, the life-span is short.It is the preparation of carrier impregnation load Mn, V, Cu, Co, Fe oxide low-temperature SCR catalyst that domestic publication (CN101352681) discloses with activated carbon; It is carrier impregnation load MnO that publication (CN101011659) discloses with activated carbon _x/ CeO ₂the preparation of low-temperature SCR catalyst.Be that catalytic benefits prepared by carrier is that specific area that absorbent charcoal carrier enriches is conducive to the dispersion of active component with activated carbon, and there is certain anti-SO ₂performance, but in activating and regenerating process, active carbon high-temp ablation is too serious, causes catalyst attrition excessive.

Summary of the invention

The present invention overcomes weak point in prior art, thering is provided a kind of convenient for production, with low cost, vanadium oxide/iron oxide nano-composite catalyst that long service life, low-temperature catalytic activity are high, is take ferriferous oxide as the composite of carrier, loaded with nano barium oxide.

Technical solution problem of the present invention adopts following technical scheme

The feature of vanadium oxide/iron oxide nano-composite catalyst of the present invention take goethite as raw material, by nano combined, is less than the barium oxide particle of 10nm at the diameter goethite crystals area load particle diameter that is 80-150nm.

The feature of vanadium oxide/iron oxide nano-composite catalyst of the present invention is also:

Described barium oxide content is in the composite not more than 10% by vanadium mass percent.

In described goethite raw material, in Hydrothermal Synthesis goethite, goethite content is not less than 98% by mass percentage; In natural goethite ore, goethite content is not less than 80% by mass percentage.

Vanadium oxide/iron oxide Nano-composite materials method of the present invention operates as follows:

(1) select natural goethite ore to be raw material, wherein the content of goethite is greater than 80%, and all the other are quartz, clay mineral impurity composition;

(2) goethite ore reduction is obtained the particle of 0.2-1mm, or grinding becomes 200 object powders;

Or select Hydrothermal Synthesis goethite to be raw material, in raw material, the content of goethite is greater than 98%;

(3) ammonium metavanadate being dissolved into mass concentration is in the oxalic acid aqueous solution of 3-10%, and in solution, vanadium concentration calculates according to the load capacity of vanadium in prepared catalyst;

(4) the isopyknic metavanadate solution impregnation of goethite particle, spend the night aging, then dry;

Or goethite powder and isopyknic metavanadate solution mixing 0.5h, spend the night aging, then dry;

(5) dried material at 250-700 DEG C, Static Calcination 0.5-2h;

Or at 250-700 DEG C, fluosolids roasting;

(6) barium oxide/ferriferous oxide nano composite material after calcining being pulverized is the powder of below 200 orders, the suspension that mass concentration is 10-50% is deployed into water, by the mode of spraying or dipping, the barium oxide/silicon/iron oxide composite material of preparation is coated in the porous structure material surface of voidage more than 80%, obtains catalyst article and be used for catalytic unit;

Or being different grades with 0.1-1mm graininess goethite dipping, material screening that is dry, calcining acquisition, as 0.1-0.3mm, 0.3-0.6mm, 0.6-1.0mm, for particles filled fixed bed catalytic reactor.

Good effect of the present invention is embodied in:

1, with synthesis TiO ₂compare, goethite source is abundanter, price is cheaper, and environmental pollution is light, prepares as carrier cost and the environmental pollution that denitrating catalyst is conducive to reducing catalyst.

2, goethite is in air atmosphere in 250-400 DEG C of calcining, and due to thermal decomposition dehydration, the bloodstone of product nano pore structure, specific area improves 7-10 doubly.

3, with synthesis TiO ₂compare, the bloodstone of goethite phase-change product nano-pore structure has stronger compatibility to the micromolecular polar gas such as ammonia, nitrogen oxide, thus shows higher adsorption activity, larger adsorption capacity to ammonia, nitrogen oxide.

4, ferriferous oxide has facilitation as denitration catalyst carrier to raising denitration activity and efficiency.

5, the bloodstone of goethite phase-change product nano-pore structure has higher acid and alkali-resistance, heat endurance, and the catalyst of preparation has the little feature of loss in application process.

Accompanying drawing explanation

Fig. 1: the field emission scanning electron microscope image of Hydrothermal Synthesis goethite, goethite presents needle-like, diameter 80-150nm.

Fig. 2: the specific area of heat treatment goethite, with the change of heat treatment temperature, shows that heat treated goethite has higher specific area between 250-400 DEG C..

Fig. 3: 300 DEG C of heat treatment goethite images of transmissive electron microscope, show because Dehydration is the bloodstone with nano-pore structure.

Fig. 4: embodiment 1 Kaolinite Preparation of Catalyst images of transmissive electron microscope.

Fig. 5: 300 DEG C of different vanadium load capacity catalyst denitration efficiencies of calcining preparation are with reaction temperature change curve.

Fig. 6: 500 DEG C of different vanadium load capacity catalyst denitration efficiencies of calcining preparation are with reaction temperature change curve.

Embodiment 1:

It is in the oxalic acid aqueous solution of 6% that 0.1g ammonium metavanadate is dissolved into 10ml mass concentration respectively;

Natural goethite ore reduction screening, obtain the particle of 0.3-0.6mm;

Take above-mentioned goethite particle 10g to join in above-mentioned metavanadate solution and flood 1-10h, then 105 DEG C of oven dry;

Dried material at 300 DEG C of calcining 0.5h;

The catalyst material of preparation is seated in micro-reaction fixed bed catalytic reactor, with air speed 9000 h ^-1gas speed, carry out at different temperature catalyze ammonia selective reduction NO denitration experiment, in 250-400 DEG C of interval, NO conversion ratio is greater than 95%(and sees Fig. 5).

Embodiment 2:

It is in the oxalic acid aqueous solution of 6% that 0.3g ammonium metavanadate is dissolved into 10ml mass concentration respectively;

Natural goethite ore reduction screening, obtain the particle of 0.3-0.6mm;

Dried material at 300 DEG C of calcining 0.5h;

Embodiment 3:

It is in the oxalic acid aqueous solution of 6% that 0.7g ammonium metavanadate is dissolved into 10ml mass concentration respectively;

Natural goethite ore reduction screening, obtain the particle of 0.3-0.6mm;

Dried material at 300 DEG C of calcining 0.5h;

Embodiment 4:

Natural goethite ore reduction screening, obtain the particle of 0.3-0.6mm;

Dried material at 500 DEG C of calcining 0.5h;

The catalyst material of preparation is seated in micro-reaction fixed bed catalytic reactor, with air speed 9000 h ^-1gas speed, carry out at different temperature catalyze ammonia selective reduction NO denitration experiment, in 250-400 DEG C of interval, NO conversion ratio is greater than 95%(and sees Fig. 6).

Embodiment 5:

Natural goethite ore reduction screening, obtain the particle of 0.3-0.6mm;

Dried material at 500 DEG C of calcining 0.5h;

The catalyst material of preparation is seated in micro-reaction fixed bed catalytic reactor, at air speed 12000 h ^-1condition under, carry out at different temperature catalyze ammonia selective reduction NO denitration experiment, in 250-400 DEG C of interval, NO conversion ratio is greater than 95%(and sees Fig. 6).

Embodiment 6:

It is in the oxalic acid aqueous solution of 6% that 0.3g ammonium metavanadate is dissolved into 20ml mass concentration respectively;

Claim synthesis goethite powder 10g to join in above-mentioned metavanadate solution to stir, become suspension;

Above-mentioned suspension on foam nickel material surface, obtain catalyst article;

The catalyst material of preparation is seated in micro-reaction fixed bed catalytic reactor, at air speed 12000 h ^-1condition under, carry out at different temperature catalyze ammonia selective reduction NO denitration experiment, in 250-400 DEG C of interval, NO conversion ratio is greater than 95%.

Embodiment 7:

200 object powders were worn in natural goethite ore reduction;

Take above-mentioned goethite powder 10g to join in above-mentioned metavanadate solution and be made into suspension;

Above-mentioned suspension on Extruded Monolithic Celluar Ceramics surface, obtain catalyst article;

The catalyst material of preparation is seated in catalytic reactor, at air speed 12000 h ^-1condition under, carry out at different temperature catalyze ammonia selective reduction NO denitration experiment, in 250-400 DEG C of interval, NO conversion ratio is greater than 95%.

Claims

1. a vanadium oxide/iron oxide denitrifying catalyst with selective catalytic reduction, it is characterized in that at nano-iron oxide area load nano vanadium oxide, in catalyst, vanadium load capacity counts 0.1 ~ 10% by vanadium mass percent, nano-iron oxide diameter 80-200nm, barium oxide diameter 2-10nm, its concrete operation step is:

(5) dried material at 250-700 DEG C, Static Calcination 0.5-2h;

Or at 250-700 DEG C, fluosolids roasting;

(6) barium oxide/ferriferous oxide nano composite material after calcining being pulverized is the powder of below 200 orders, the suspension that mass concentration is 10-50% is deployed into water, by the mode of spraying or dipping, the barium oxide/silicon/iron oxide composite material of preparation is coated in the porous structure material surface of porosity more than 80%, obtains catalyst article and be used for catalytic unit;

Or the material obtained with 0.1-1mm graininess goethite dipping, drying, calcining, sieve as 0.1-0.3mm, 0.3-0.6mm, 0.6-1.0mm, for fixed bed catalytic reactor.