Low-temperature flue gas denitration catalyst for selectively reducing NOx by using CO and application thereof

Abstract

The invention provides a low-temperature flue gas denitration catalyst for selectively reducing NOx by using CO. The low-temperature flue gas denitration catalyst comprises 20-50% of SSZ-13 molecular sieve in terms of hydrogen form, 5-12% of copper in terms of CuO and 4-8% of manganese in terms of MnO. The preparation method comprises the following steps of adding an aqueous solution of nitrates of Cu and Mn into an ammonium type SSZ-13 molecular sieve, carrying out ion exchange, filtering, washing with water, drying, and roasting at 550-580 DEG C to obtain Cu-Mn / SSZ-13 molecular sieve roasting powder which contains 2-4% of CuO and 1-2% of MnO, uniformly mixing 30-60 parts of Cu-Mn / SSZ-13 molecular sieve roasting powder, 5-12 parts of basic cupric carbonate, 4-11 parts of manganese carbonate and 30-50 parts of washed kaolin, spraying 100-130 parts of aluminum phosphate sol-pseudo-boehmite composite glue solution, kneading, extruding into strips, drying, and roasting at 500-550 DEG C, soaking the roasted strip in an acetic acid aqueous solution, drying, and roasting for 2-4 hours at 300-330 DEG C under an air isolation condition to prepare the low-temperature flue gas denitration catalyst. Under the conditions that the temperature is 120-160 DEG C, and the concentration of CO is 10-200% more than that required by the reaction with NOx to generate N2, NOx below 2000 mg / m<3> can be treated to be smaller than or equal to 60 mg / m<3>, and NOx with the concentration of 300-500 mg / m<3> can be treated to be smaller than or equal to 40 mg / m<3>.

Description

technical field [0001] The invention belongs to the technical field of NOx-containing gas treatment, and in particular relates to a low-temperature flue gas denitrification catalyst using CO to selectively reduce NOx and its application. Background technique [0002] In industrial production, there are many combustion and roasting processes with a small amount of tail gas, and the exhaust stream contains a relatively low concentration such as 300-3000mg / m 3 NOx and CO with a slightly higher concentration, the gas flow temperature is lower such as 100-160 °C, and there are generally fluctuations in temperature and gas flow. This kind of gas is treated by dry chemical denitrification agent, or wet chemical absorption denitrification treatment, which can reach 200 or 100mg / m 3 However, it is inconvenient to pass the selective catalytic reduction reaction (NH 3 -SCR) for denitrification. The dry chemical denitrification treatment has high cost of solid denitrification agent a...

AI Technical Summary

Problems solved by technology

In this study, due to the high concentration of CO, when the conversion rate is high, the catalyst particles and bed temperature will increase significantly, thereby improving the NO removal rate. If the volume concentration of CO is 0.15%, the catalyst particles and bed temperature When the temperature is at the corresponding value, the NO removal rate will drop significantly

On the other hand, when an alumina carrier calcined at a temperature below 850°C is used, because of its high activity, a nitration reaction will occur at a temperature below 180°C and oxygen-containing conditions, resulting in the gradual deactivation of the catalyst; 850°C The alumina carrier calcined at the above temperature is not suitable for the preparation of the catalyst due to its low specific surface

[0007] There is also the prior art of using noble metals as catalyst active components, which has high activity in the low-temperature reaction of CO selective reduction of NOx, but the cost is too high, and it is not easy to apply in ordinary occasions