Flat plate type SCR catalyst for denitration of arsenic-rich high-ash flue gas and preparation method of flat plate type SCR catalyst

Abstract

The invention relates to a flat plate type SCR catalyst for denitration of arsenic-rich high-ash flue gas and a preparation method of the flat plate type SCR catalyst. The catalyst takes a nano tubular TiO2-Sb2O3-5A molecular sieve as a carrier, and the catalyst comprises the following components in parts by mass: 70 to 80 parts of a TiO2-Sb2O3-5A molecular sieve, 0.5 to 1 part of V2O5, 2 to 4 parts of Nb2O5, 10 to 12 parts of MoO3, 3 to 5 parts of SiO2, 2 to 5 parts of Al2O3 and 1 to 3.5 parts of CaO. The preparation method comprises the steps: preparing a nanotube TiO2-Sb2O3 solid through a coprecipitation method, mixing the solid with a 5A molecular sieve through a mechanical method to obtain a TiO2-Sb2O3-5A molecular sieve mixed carrier, sequentially adding a vanadium solution, a molybdenum solution, a niobium solution and a forming aid into the mixed carrier, stirring to obtain catalyst pug, and finally obtaining the flat plate type SCR catalyst through a rolling method. The preparation method is simple, the steps are easy to operate, the flat plate type denitration catalyst has excellent arsenic poisoning resistance and mechanical performance and can be applied to four-stage arsenic-containing coal for combustion and arsenic-rich high-ash flue gas with the ash concentration of 60-100 g / m<3>, and when the arsenic adsorption capacity of the catalyst reaches 8%, the denitration efficiency of the catalyst can still be stabilized to be 90% or above.

Description

technical field [0001] The invention relates to a flat-plate SCR catalyst for denitrification of arsenic-rich and high-ash flue gas and a preparation method thereof, belonging to the technical field of catalyst preparation. Background technique [0002] Coal-fired flue gas fly ash contains a large amount of alkali metals (such as sodium, potassium, etc.), alkaline earth metal elements (such as calcium), phosphorus (P), sulfur (S) and arsenic (As), which makes the denitrification catalyst chemical poisoning phenomenon in Occurs frequently during flue gas treatment of coal-fired and biomass-fired boilers. Among them, the arsenic present in the fly ash, as an inorganic highly toxic substance, can cause a strong deactivation effect on the denitrification catalyst. Studies have shown that As in flue gas 2 o 3 Molecules can not only block the pores of the catalyst, but also often be adsorbed on the carrier and react with the active site to form a stable compound without catalyt...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problems that existing SCR catalysts are prone to catalyst poisoning when used in the state of high arsenic-containing flue gas, the service life is shortened, and the use cost of the catalyst is high. Formula SCR catalyst and preparation method thereof

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