Preparation method of semi-coke flue gas denitrfying agent used in low-temperature catalytic oxidation

Abstract

The invention discloses a preparation method of a semi-coke flue gas denitrfying agent used in the low-temperature catalytic oxidation. The method is characterized in that the denitrfying agent is prepared from semi-coke through acid activation, alkali activation and high-temperature activation; the acid activation process comprises the following steps: mixing semi-coke particles with an acidic solution with the mass concentration of 5-85% in the liquid solid ratio of 0.5-5.0, processing the mixture at 30-100 DEG C for 0.5-8h, rinsing the product to be neutral and drying at 110 DEG C for 6h; the alkali activation process comprises the following steps: mixing the product of the acid activation process with an alkaline solution with the mass concentration of 5-85% in the liquid solid ratio of 0.5-5.0, processing the mixture at 30-100 DEG C for 0.5-8h, rinsing the product to be neutral and drying at 110 DEG C for 6h; and the high-temperature activation process comprises the following steps: roasting the product of the alkali activation process in N2 atmosphere with 0-10% of O2 for 1-8h under the conditions that the temperature is 500-800 DEG C, the airspeed is 50-1000h<-1> and the moisture content is 0-90%. The invention is characterized in that semi-coke has wide sources and cheap price and the prepared catalyst can be used in the low-temperature (not more than 110 DEG C) catalytic oxidation for removing NOx in the flue gas.

Description

Technical field [0001] The invention relates to a low-temperature catalytic oxidation method for removing NO in flue gas X The preparation method of the denitrification agent, more specifically, is a preparation method of the active semi-coke flue gas denitrification agent capable of supporting metal oxides. Background technique [0002] The NOx in coal-fired flue gas is one of the main pollutants in the atmospheric environment. Judging from the year-by-year inspections in my country, since the 1990s, the concentration and precipitation of nitrate in rainfall are gradually increasing, and the ratio of nitrate to sulfate in precipitation is changing. Acid rain in China is heading towards H 2 SO 4 With HNO 3 Mixed acid rain transformation. In Beijing, Guangzhou, the Pearl River Delta, Hong Kong and other places, the concentration of NOx has exceeded SO 2 . According to statistics from the National Bureau of Statistics of China, my country’s coal-fired flue gas NOx emissions in 200...

AI Technical Summary

Problems solved by technology

This method has the following disadvantages: (1) the catalyst is expensive and economically unreasonable; (2) the NH must be strictly controlled 3 stoichiometric ratio to NO, otherwise unreacted NH 3 Will cause secondary pollution, in addition to NH 3 The equipment corrosion problem caused by leakage is difficult to avoid and overcome; (3) SCR reaction temperature must generally be above 200°C, and NSCR technology must be above 700°C, which is not well matched with the temperature of the electrostatic precipitator, resulting in serious wear and tear on the catalyst by dust. Higher energy consumption; (4) SO 2 It can promote the removal of NOx, and the removal of NOx should be set before desulfurization, causing the equipment to be easily corroded; (5) The operating conditions are harsh, and the gas source needs to be pretreated to prevent catalyst poisoning

At present, the biggest problem of catalytic oxidation of NO by activated carbon catalysts is that the catalytic activity decreases rapidly with the increase of temperature; the existence of water vapor in the flue gas makes it difficult to increase the conversion rate of catalytic oxidation of NO by activated carbon; the cost of activated carbon is expensive, which limits the promotion of activated carbon-based catalysts