Integrated process for pyrolyzing urea for medium- and low-temperature SCR (Selective Catalytic Reduction) denitration and regenerating catalyst

Abstract

The invention discloses an integrated process for pyrolyzing urea for medium- and low-temperature SCR (Selective Catalytic Reduction) denitration and regenerating a catalyst. A denitration reactor isadopted for SCR denitration; the denitration reactor comprises a flue; and the pyrolyzation of the urea is carried out in high-temperature fumes generated by the combustion in a combustion furnace. The integrated process is characterized by comprising the following steps of 1), extracting partial desulfurated fumes in the flue as an oxidizing agent by utilizing a blower system to combust in an afterburner system; 2), mixing the high-temperature fumes generated by the combustion with a urea solution sprayed by an urea spraying system; and 3), after an obtained product is mixed with original fumes through a fume mixing system, using the obtained mixture as a denitration reducer to enter an SCR reactor to carry out denitration. The process is small in the quantity of devices; and the energy consumption is effectively decreased.

Description

technical field [0001] The invention relates to an integrated process of urea pyrolysis and catalyst regeneration for medium and low temperature SCR denitrification. Background technique [0002] With the improvement of national environmental protection requirements, the tail gas treatment of existing iron and steel plants adopts the method of wet desulfurization + burner + urea pyrolysis (hydrolysis) + medium and low temperature SCR denitrification. Among them, urea pyrolysis usually uses electric heating or steam heating to raise the temperature of the heat medium brought by the blower to 650°C and enters the pyrolysis furnace. The urea solution is sprayed into the pyrolysis furnace through the urea injection system. When the urea solution encounters high-temperature gas After that, it is directly vaporized and pyrolyzed into ammonia gas, and the generated ammonia gas enters the flue through the pipeline, passes through the ammonia injection grid, mixes with the flue gas, ...

AI Technical Summary

Problems solved by technology

Because ammonium bisulfate will be formed in the environment of medium and low temperature (180-220°C) to adhere to the surface of the catalyst, resulting in the failure of the catalyst activity, the catalyst needs to be regenerated before it can be used, and the catalyst needs to be returned to the factory for regeneration, which seriously affects the system production

This original technology not only has the disadvantages of complex process route, many equipment, large site requirements, and high energy consumption, but also has complex catalyst regeneration process and system shutdown, which has a great impact on the production process.

Images