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

Abstract

The invention relates to a preparation method for a low-temperature porous SCR denitration catalyst for a gas turbine unit, and belongs to the field of preparation of flue gas denitration catalysts. A large amount of pore forming agents and mechanical strengthening agent are required to be added in the preparation of a porous catalyst, so that the viscosity of a material is increased, and the filtering difficulty when the porous catalyst is formed is increased. Because the flue gas exhaust temperature of the gas turbine unit is high, the afterheat in the range from the flue gas exhaust temperature to the maximal active temperature of the catalyst can be recycled and the energy utilization rate can be improved if the active temperature of the catalyst can be reduced. The invention discloses the preparation method for the low-temperature porous SCR denitration catalyst for the gas turbine unit. The preparation method comprises the following steps: mixing, forming, drying and calcining; the step of mixing comprises the modes of dry mixing, wet mixing and dehumidifying; continuous material discharging time of filtering can be prolonged by changing the modes of the mixing; the elements, namely, praseodymium and cerium, are added into the formula, so that the catalyst is endowed with low-temperature denitration performance; an SCR porous catalyst wet embryo extruding filtering plate device is adopted, so that the catalyst is hard to damage, and the filtering effect can be improved.

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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