A kind of denitrification catalyst and its preparation method and low temperature denitrification process

Abstract

The invention discloses a denitration catalyst, a preparation method and a low temperature denitration process. Denitration catalyst, based on catalyst weight, including: 75%~94% carbon-containing alumina carrier, 3%~20% Fe 2 O 3 and 3%~20%MnO 2 ; Based on the weight of the carbon-containing alumina carrier, the carbon content is 5wt%-35wt%, preferably 10wt%~30wt%, and the specific surface area is 250-750m 2 / g, the crushing strength is 100‑200N / cm. The denitration catalyst of the invention has larger pore volume, specific surface and mechanical strength, and can be used in low temperature denitration reaction, can effectively remove nitrogen oxides and sulfur oxides in flue gas, and will not cause ammonium hydrogen sulfate to block the bed The problem of the layer prolongs the operation cycle of the device.

Description

technical field [0001] The invention belongs to the technical field of flue gas denitration, and in particular relates to a denitration catalyst, a preparation method and a denitration process. Background technique [0002] Nitrogen oxides, collectively referred to as NOx, are one of the main sources of air pollution. The most harmful ones are: NO, NO 2 . The main hazards of NOx are as follows: (1) toxic to the human body; (2) toxic to plants; (3) can form acid rain and acid fog; (4) form photochemical smog with hydrocarbons; (5) destroy the ozone layer . [0003] Flue gas denitrification refers to the removal of NOx in flue gas. According to the treatment process, it can be divided into wet denitrification and dry denitrification. Mainly include: acid absorption method, alkali absorption method, selective catalytic reduction method, non-selective catalytic reduction method, adsorption method, plasma activation method, etc. Some researchers at home and abroad have also ...

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Problems solved by technology

[0006] There are following problems in prior art: 1, because generally contain SO in flue gas 2 , SO 3 , O 2 With water vapor, when there is excess ammonia in the reaction zone (ammonia escape) it will combine with SO 3 The reaction generates ammonium salt, and the ammonium salt (NH 4 HSO 4 ), in a liquid state at a temperature of 180-240 ° C, with viscosity, and is easy to adhere to the heat exchange tube of the economizer, a downstream device of the SCR denitrification reactor, and stick to the dust in the flue gas, causing scaling and blockage of the heat exchange tube layer Corrosion, affecting the operating cycle of the device

2. The NOx content in the flue gas is related to the process conditions of the main device, and the fluctuation range is relatively large. However, the catalyst amount of the SCR fixed bed reactor is fixed. Once the NOx concentration range exceeds the design value, the NOx of the purified flue gas cannot Discharge

Therefore, the operating flexibility of the fixed bed is less

[0007] 3. During the operation of the fixed-bed reactor, the activity of the catalyst gradually decreases. When the NOx at the outlet of the reactor cannot meet the standard discharge, the catalyst needs to be replaced

It can be seen that the utilization rate of the catalyst in the fixed bed SCR reactor is too low

4. After denitrification of flue gas, wet scrubbing and dust removal should be used together with desulfurization. The desulfurization waste liquid generated in the desulfurization and dust removal process also needs to be separated from liquid to solid. The process is long, the operation is complicated, and the investment and operation costs are high.

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