Preparation method of low-temperature porous SCR denitrification catalyst for gas-fired units

Abstract

The invention relates to a method for preparing a low-temperature porous SCR denitration catalyst for gas units, and belongs to the field of flue gas denitration catalyst preparation. The preparation of porous catalysts requires the addition of more pore-forming agents and mechanical strengthening agents, which increases the viscosity of the material and increases the difficulty of filtration during molding. Since the exhaust gas temperature of the gas unit is relatively high, if the catalyst activity temperature can be reduced, the waste heat within the range from the exhaust gas temperature to the maximum activity temperature of the catalyst can be recycled and utilized to improve energy utilization. The invention discloses a method for preparing a low-temperature porous SCR denitration catalyst for gas units, which includes the steps of mixing, shaping, drying, and calcining. The mixing steps include dry mixing, wet mixing, and dehumidification steps. The change of the mixing method can increase The continuous discharge time of filtration; adding praseodymium and cerium elements to the formula gives the catalyst low-temperature denitration performance; using SCR porous catalyst wet embryo extrusion filter plate device, which is not easy to be damaged and can improve the filtration effect.

Description

technical field [0001] The invention relates to a preparation method of a low-temperature porous SCR denitrification catalyst for a gas unit, and belongs to the technical field of flue gas denitrification. Background technique [0002] In recent years, the demand for natural gas is growing at an annual rate of 8%. For a period of time in the future, natural gas will be the most important form of energy to adjust the energy structure in my country. Because the dust content in the flue gas of gas-fired units is much lower than that of coal-fired units, there are stricter requirements for the wall thickness of SCR honeycomb catalysts. Now The thickness of the inner wall of the SCR honeycomb denitration catalyst unit used in coal-fired power plants is about 0.8mm, while the thickness of the inner wall of the catalyst used in gas-fired units is less than 0.4mm. [0003] This means that the low-temperature porous SCR denitrification catalyst for gas-fired units should have larger ...

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Problems solved by technology

[0003] This means that the low-temperature porous SCR denitrification catalyst for gas-fired units should have larger pore size and higher mechanical strength. In order to increase the pore size and mechanical strength of the catalyst, more pore-forming agents and mechanical strengthening agents need to be added, resulting During the mixing stage of catalyst preparation, the viscosity of the material increases, making it difficult to filter

In addition, because the addition ratio of pore forming agent, mechanical strengthening agent and other materials is different from that of SCR denitrification catalyst used in coal-fired units, the required environmental conditions are also different in the drying stage and the cooling stage of calcination. If the control is not proper, It will cause the catalyst to crack, so that the whole batch of catalyst will be scrapped or the catalytic effect will be greatly affected

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