CN110252333A - A kind of preparation method and application of SCR mercury removal catalyst - Google Patents

Abstract

The invention discloses a preparation method and application of an SCR mercury removal catalyst, and relates to the technical field of flue gas purification. The preparation method includes: preparing the support by co-precipitation; the support includes TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ ; preparing the catalyst composition by impregnation; the active component of the catalyst support composition is selected from Fe , Cu, Mn, V, W, Mo, Cr, Co, or one or several metal salts; Dissolve various catalyst loading compositions in 100mL distilled water in a certain proportion, then add a certain amount of carrier, and magnetically stir 2h, stand at room temperature for 1h, dry at 120°C for 12h, then place in a muffle furnace at 200-600°C for 6h, grind and sieve catalyst particles of 40-80 meshes for use after natural cooling. The invention uses TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ carriers to immobilize the catalyst to catalyze and oxidize _NOx and mercury in the flue gas, thereby realizing denitrification and mercury removal of the flue gas.

Description

A kind of preparation method and application of SCR mercury removal catalyst

technical field

The invention belongs to the technical field of flue gas purification, and in particular relates to a preparation method and application of an SCR mercury removal catalyst.

Background technique

As the main source of air pollution problems such as acid rain, photochemical smog, and haze, the prevention and control of nitrogen oxides (NOx) has become an urgent problem to be solved. Due to the biotoxicity, persistence and bioaccumulation effect of mercury, the control of mercury pollution in coal-fired flue gas has attracted extensive attention from the international community in recent years. my country is the largest anthropogenic mercury emitter in the world. The direct combustion of a large amount of coal is the main source of anthropogenic mercury emissions in my country. It is imminent to control the emission of mercury in coal combustion flue gas.

Selective Catalytic Reduction (SCR) technology, as the most mature and effective denitrification technology, has been widely used in various coal-fired power plants. Mercury in coal-fired flue gas mainly exists in three forms: elemental mercury (Hg ^{0 )} , particulate mercury (Hg ^p ) and oxidized mercury (Hg ²⁺ ). Hg ⁰ is extremely volatile and insoluble in water, and is difficult to be burned by coal. The existing APCDs removal in the power plant, so the key to controlling coal-fired mercury emissions is to control the emission of Hg ^0. Due to the high water solubility of Hg ²⁺ , Hg0 in coal-fired flue gas is oxidized to Hg ²⁺ , and then wet desulfurization is used Systematic (WFGD) removal of Hg ²⁺ is considered to be a potential coal-fired mercury pollution control technology.

Contents of the invention

The object of the present invention is to provide a preparation method and application of an SCR mercury removal catalyst, by using TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ carriers to immobilize the catalyst to catalytically oxidize NO _x and mercury in flue gas , so as to realize flue gas denitrification and mercury removal.

In order to solve the problems of the technologies described above, the present invention is achieved through the following technical solutions:

The invention is a preparation method of an SCR demercuration catalyst, comprising:

Preparation of carrier by co-precipitation method;

Wherein, the carrier includes TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ ;

Catalyst composition is prepared by impregnation method;

Wherein, the active component of the catalyst loading composition is selected from one or more metal salts of Fe, Cu, Mn, V, W, Mo, Cr, Co;

Dissolve the catalyst-loaded composition in 100mL of distilled water in a certain proportion, and then add a certain amount of carrier, the carrier is TiO ₂ , Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.1 O ₂ carrier, stir magnetically for 2 hours, and Let it stand for 1 hour, dry at 120°C for 12 hours, then place it in a muffle furnace at 200-600°C for 6 hours, grind and sieve catalyst particles of 40-80 meshes for use after natural cooling.

Among them, Fe, Cu element, Mn element, CeO ₂ , V ₂ O ₅ , W element, Mo element, Cr element, and Co ₃ O ₄ in the above-mentioned catalyst supporting composition account for 0-10% and 0-5% of the total mass of the carrier, respectively. %, 0-40%, 0-60%, 0-9%, 0-50%, 0-15%, 0-10%, 0-30%.

An application of an SCR mercury removal catalyst, the application of the SCR mercury removal catalyst in the removal of SO ₂ , NOx, and Hg in flue gas.

The present invention has the following beneficial effects:

1. The present invention uses TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ carrier immobilized catalysts to catalyze and oxidize NO _X and mercury in flue gas, thereby realizing flue gas denitrification and mercury removal.

2. The present invention can complete denitrification and mercury removal at the same time, and is suitable for the removal of sulfur dioxide, H ₂ O, nitrogen oxides and mercury in flue gas components containing a certain amount.

Of course, any product implementing the present invention does not necessarily need to achieve all the above-mentioned advantages at the same time.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the accompanying drawings that are required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. Those of ordinary skill in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is a structural schematic diagram of an experimental device for combined catalytic removal of SO ₂ /NOx/Hg from flue gas.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

In describing the present invention, it is to be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "surrounding" etc. Indicating orientation or positional relationship is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the components or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as limiting the present invention .

The invention is a preparation method of an SCR demercuration catalyst, comprising:

Preparation of carrier by co-precipitation method;

Wherein, the carrier includes TiO _{2 ,} Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.10 O ₂ ;

Catalyst composition is prepared by impregnation method;

Wherein, the active component of the catalyst loading composition is selected from one or more metal salts of Fe, Cu, Mn, V, W, Mo, Cr, Co;

A certain amount of iron nitrate Fe(NO) ₃ , copper nitrate Cu(NO ₃ ) ₂ -3H ₂ O, manganese acetate Mn(CH ₃ COO) ₂ ·4H ₂ O, cerium nitrate Ce(NO ₃ ) ₃ ·6H ₂ O, ammonium metavanadate NH ₄ VO ₃ , ammonium tungstate, ammonium molybdate H ₈ MoN ₂ O ₄ , Cr(NO ₃ ) ₃ 9H ₂ O, Co ₃ O ₄ , Na ₂ WO ₄ 5H ₂ O( Among them, Fe, Cu, Mn, CeO ₂ , V ₂ O ₅ , W, Mo, Cr, Co ₃ O ₄ account for 5%, 3%, 20%, 30%, 5%, 0-50% of the total mass of the carrier respectively , 8%, 5%, 15%), once dissolved in 100mL distilled water, and then add a certain amount of carrier (what is the specific ratio), the carrier is TiO ₂ , Zr _0.5 Ti _0.5 O ₂ and Zr _0.45 Ti _0.45 Ce _0.1 O ₂ carrier, magnetic stirring for 2 hours, standing at room temperature for 1 hour, drying at 120°C for 12 hours, then conditioning at 200-600°C and roasting in a muffle furnace for 6 hours, after natural cooling, grinding and sieving catalyst particles of 40-80 meshes for use.

An application of an SCR mercury removal catalyst, the application of the SCR mercury removal catalyst in the removal of SO2, NOx, and Hg in flue gas.

An experimental device for catalytic combined removal of SO ₂ /NOx/Hg in flue gas;

As shown in Figure 1, it includes N ₂ steel cylinder a1, O ₂ steel cylinder 2, SO ₂ /N ₂ steel cylinder 3, NO/N ₂ steel cylinder 4, NH ₃ /N ₂ steel cylinder 5; the above steel cylinders 1-5 all have mass flow meters control gas flow,

Water vapor generating device 6, heating electric furnace 7, transformer 8 for temperature control, gas mixing cylinder 9, thermometer 10, stainless tube catalytic reactor 11, holding furnace 12, ammonia absorption bottle 13, flue gas analyzer 14, N2 cylinder a15, mercury generator 16, _KCl solution bottle 17, SnCl2 solution bottle 18, mercury analyzer 19 and tail gas treatment device 20.

The outlets of N ₂ steel cylinder a1 and O ₂ steel cylinder 2 respectively pass through the mass flowmeter connected to them and then enter the water vapor generator 6; SO ₂ /N ₂ steel cylinder 3 and NO/N ₂ steel cylinder 4 are mixed and then enter the gas mixing cylinder 9 and pass through The gas in the _N2 cylinder a1 and _O2 cylinder 2 of the water vapor generator 6 is mixed, and the _NH3 / _N2 cylinder 5 directly enters the reactor 11; the _N2 cylinder b15 carries mercury vapor through the mercury generator 16 and then enters the reaction device 11, the catalytic reactor inlet on the upper end cover of the photocatalytic reactor 11 is connected all the way, and the flue gas analyzer 14 is connected all the way;

Catalytic reactor 11, its structural schematic diagram as shown in Figure 1, comprises photocatalytic reactor entrance, the upper end cover of catalytic reactor top, insulation layer, and catalyst carrier titanium wire mesh, and titanium wire mesh is positioned at the lower end of catalytic reactor bottom.

The catalyst is placed on a wire mesh in a stainless steel tube reactor.

The catalytic reactor is made of stainless steel; the insulation layer is wrapped outside the catalytic reactor cylinder;

The upper end of the catalytic reactor 11 is provided with a catalytic reactor inlet, i.e. the inlet of the flue gas, and the lower end cover at the bottom is provided with a catalytic reactor outlet, i.e. the exhaust outlet of the flue gas, which is divided into three paths, all the way into the liquid phase absorption The reactor 13 enters the flue gas analyzer 14; one path enters the KCl solution bottle 17 and the _SnCl solution bottle 18 respectively and then enters the mercury analyzer 19 for analysis and measurement, and the computer outputs the measurement results; the other path leads to the tail gas treatment device 20.

The reactor 6 controls the temperature and controls the _H2O content through a pressure-controlled heating device 8;

The method for combined removal of NOx/Hg in flue gas by using the above-mentioned experimental device for removing NOx/Hg in flue gas with catalyst is as follows:

NO, SO ₂ , O ₂ , N ₂ gases in the simulated flue gas respectively pass through the mass flow meter, and are mixed with the Hg vapor generated in the mercury vapor generator 16 and the water vapor generated by the water vapor generator 6 in the reactor 11 The generated mixed simulated flue gas of NO, SO ₂ and Hg enters the catalytic reactor 11 from the upper part.

Different mass flowmeters can control the gas flow of different components, and the change of water vapor and Hg steam components is adjusted by controlling the gas volume passing through the water vapor generator or the mercury vapor generator 16 .

Enter flue gas analyzer ₁₄ by the gas after acidic solution absorption treatment, measure NO, SO in the gas before and after reaction and Hg concentration change, calculate removal efficiency,

This catalyst has high removal efficiency of SO ₂ /NOx/Hg in simulated flue gas,

Thus, it is shown that the combined removal of NOx/Hg in flue gas by using a catalyst of the present invention is feasible.

The catalyst has a catalytic effect on NOx and Hg, reducing it to _N2 and oxidizing it to divalent mercury. Divalent mercury is easily soluble in water and can be directly absorbed and removed by the solution. In order to express the removal effect of NO, SO ₂ and Hg after being catalyzed and oxidized and absorbed by the absorption liquid, the concentration of NO, SO ₂ and Hg at the inlet of the catalytic reactor device is set as C1, C2 and C3, and the outlet of NO is absorbed by the liquid phase. , SO ₂ and Hg concentrations are C4, C5 and C6, then the removal efficiencies of catalytic oxidation combined with liquid phase absorption to remove NO, SO ₂ and Hg are:

In the description of this specification, descriptions with reference to the terms "one embodiment", "example", "specific example" and the like mean that specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment of the present invention. In an embodiment or example. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are only to help illustrate the invention. The preferred embodiments are not exhaustive in all detail, nor are the inventions limited to specific embodiments described. Obviously, many modifications and variations can be made based on the contents of this specification. This description selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The invention is to be limited only by the claims, along with their full scope and equivalents.

Claims (2)

1. a kind of preparation method of SCR demercuration catalyst characterized by comprising

Carrier is prepared with coprecipitation；

Wherein, the carrier includes TiO_2、Zr_0.5Ti_0.5O₂And Zr_0.45Ti_0.45Ce_0.10O₂；

With preparation catalyst composition；

Wherein, catalyst load combinations object active component is selected from one of Fe, Cu, Mn, V, W, Mo, Cr, Co or several gold Belong to salt；

Catalyst load combinations object is dissolved in 100mL distilled water, a certain amount of carrier, carrier TiO are added₂, Zr_0.5Ti_0.5O₂And Zr_0.45Ti_0.45Ce_0.1O₂Carrier, magnetic agitation 2h stand lh under room temperature, then dry 12h at 120 DEG C exists It is placed in Muffle furnace at 200-600 DEG C and roasts 6h, ground and sieve after natural cooling and take the catalyst granules of 40~80 mesh spare.

2. a kind of application of SCR demercuration catalyst of preparation method preparation as described in claim 1, which is characterized in that the SCR Demercuration catalyst SO in removing flue gas₂, NOx, Hg application.