Vanadium/Titania Catalyst Comprising Natural Manganese Ore for Removing Nitrogen Oxides and Dioxin in Wide Operating Temperature Range and Method of Using the Same

Abstract

Disclosed is a vanadium / titania-based catalyst including natural manganese ore for removing nitrogen oxides and dioxin in a wide operating temperature range and a method of using the same. Specifically, this invention pertains to a vanadium / titania (V / TiO2)-based catalyst including natural manganese ore for removing nitrogen oxides and dioxin in a wide operating temperature range, in which the WTiO2 catalyst for selective catalytic reduction of nitrogen oxides and removal of dioxin contained in flue gas includes 5-30 wt % of natural manganese ore, thus exhibiting excellent activity of removing nitrogen oxides even in the low temperature range and of removing dioxin at the same time, and to a method of using the same. The catalyst of this invention has good thermal stability and thus can simultaneously manifest nitrogen oxides removal performance and dioxin removal performance superior to conventional vanadium / titania catalysts in a wide temperature range (150˜450° C.) including not only a high temperature range but also a low temperature range. As well, since unreacted ammonia emissions can be reduced, the formation of an ammonium salt is prevented and ammonium nitrate is decomposed at low temperatures, thus solving the problems of inactivation of the catalyst due to catalytic poisoning and of a shortened lifetime thereof, leading to economic benefits.

Description

TECHNICAL FIELD[0001]The present invention relates to a vanadium / titania-based (V / TiO2) catalysts comprising natural manganese ore (NMO) for removing nitrogen oxides and dioxin in a wide operating temperature range and a method of using the same. More particularly, the present invention relates to a V / TiO2 catalyst comprising NMO for removal of nitrogen oxides and dioxin in a wide operating temperature range, in which the V / TiO2 catalyst is mixed with NMO to increase the activity of removal of nitrogen oxides in the low temperature range so as to effectively remove nitrogen oxides and dioxin not only at high temperatures but also at low temperatures, and to a method of using the same.BACKGROUND ART[0002]Generally, fossil fuels are burned to produce energy for thermal power plants and industrial complexes, and also are burned in incinerators to decrease the volume of waste and to increase the chemical stability thereof. In such cases, various hazardous flue gases, such as carbon diox...

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Benefits of technology

[0024]Leading to the present invention, intensive and thorough research into the effective removal of dioxin, as well as nitrogen oxides through SCR using an ammonia reducing agent not only at low temperatures of 250° C. or less but also at high temperatures of 300˜400° C., carried out by the present inventors, aiming to overcome the problems encountered in the prior art, resulted in the finding that a predetermined amount of NMO can be added to a V / TiO2 catalyst to form a novel composite oxide, which thus can exhibit excellent denitrification performance not only at high temperatures but also at low temperatures and which furthermore can remove dioxin.

[0025]Accordingly, an object of the present invention is to provide a vanadium / titania catalyst comprising NMO for removing nitrogen oxides and dioxin in a wide operating temperature range, capable of exhibiting excellent activity of removal of nitrogen oxides and dioxin not only at high temperatures but also at low temperatures.

Problems solved by technology

Among these flue gases, nitrogen oxides function as an environmental pollutant, which is harmful to the human body and causes photochemical smog or decreases a visibility distance.

The V / TiO2 catalyst typically has high activity at 300˜400° C., but is decreased with respect to nitrogen oxides removal efficiency due to low activation energy at temperatures lower than the above temperature.

On the other hand, at temperatures higher than the above temperature, the ammonia reducing agent is oxidized, thus the stoichiometric ratio of the reaction becomes inappropriate, undesirably decreasing the efficiency.

Further, the thermal fatigue of the catalyst is increased, leading to a shortened catalyst lifetime.

In addition, sulfuric acid produced in Reaction 8 corrodes a catalyst bed and equipment in the subsequent stage of the system.

Generally, for efficient SCR in the presence of the V / TiO2 catalyst, since the temperature of the flue gas should be maintained high in the range of 300˜400° C., a process capable of supporting SCR is limited in the flue gas disposal process.

However, due to dust and / or sulfur dioxide having high concentration, the active sites of the denitrification catalyst may be lessened, and also the denitrification catalyst may be abraded.

Further, ammonium sulfate may be formed in equipment in the subsequent stage of the system due to the oxidation of sulfur trioxide (SO3), leading to corrosion of such equipment.

In this way, flue gas denitrification using a conventional commercially available V / TiO2 catalyst is a process that consumes a large amount of energy depending on the high-temperature activity of a denitrification catalyst.

That is, when the amount of the catalyst is increased, not only the catalyst cost but also the costs related to a catalyst reactor, a duct, the amount of reducing agent and the reducing agent supply are increased, and as well, the pressure loss of the flue gas is increased, negatively affecting the total system.

The high-temperature operation facilitates thermal fatigue of the catalyst bed, undesirably shortening the lifetime of the catalyst.

Further, since sulfur dioxide is highly oxidized ammonium sulfate, acting as a cause of corrosion, is formed in equipment in the subsequent stage of the system for SCR.

Furthermore, dioxin is nobiodegradable, stable even at 700° C., and accumulates in the body and thus negatively affects the human body, causing side effects too numerous to be completely listed, and including cancers, reproduction toxicity, malformation, liver toxicity, thyroid gland disorders, cardiac disorders, etc.

3) turbulence due to the geometry of the incinerator and second air injection.

However, due to the problems with techniques and performance of the catalyst bed, the control of dioxin is mainly dependent on adsorption using an adsorbent, such as activated carbon and calcium hydroxide.

Moreover, the reproduction or disposal of the adsorbent having dioxin adsorbed thereon is technically difficult, and thus an economic burden may be imposed.

That is, presently available methods of adsorbing dioxin in the flue gas using activated carbon suffer because the activated carbon on which dioxin is adsorbed is difficult to reproduce or dispose, and thus economic benefits are negated.

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