Denitration device and process for introducing high temperature flue gas for urea pyrolysis for ammonia production

Abstract

The invention discloses a denitration device and process for introducing high temperature flue gas for urea pyrolysis for ammonia production, part of the high temperature flue gas in a boiler rear smoke channel is introduced into pyrolyzers for pyrolysis of an atomized urea solution, after pyrolysis of the atomized urea solution, ammonia gas is generated; gases after the pyrolysis are fully mixed with flue gas discharged from the boiler rear smoke channel; and N2 and H2O are generate by reduction reaction of the nitrogen oxides and the ammonia gas contained in the mixed gas under the effect of a catalyst, and so that the nitrogen oxides in the flue gas discharged from the boiler rear smoke channel can be removed. The beneficial effects are that: same denitrification effect can be achieved without an additional electric heater and steam heating, energy consumption can be saved to the maximum extent, cost is reduced, the urea pyrolysis is full, urea crystallization on the catalyst and an air preheater can be prevented, and urea corrosion of the heating surface and the heat transfer surface of the boiler rear smoke channel caused by urea direct injection can be prevented.

Description

technical field [0001] The invention relates to the technical field of flue gas purification, in particular to a denitrification device and process for using high-temperature flue gas to produce ammonia by urea pyrolysis. Background technique [0002] Coal-fired boilers are an important means of energy production in my country. With the development of the national economy, energy consumption is increasing year by year, and the accompanying air pollution problem has gradually become prominent and has become the focus of attention. Among them, nitrogen oxides (NOx), as one of the three major air pollutants, have received more and more attention, and flue gas denitrification has become a key area of ​​national pollution control. [0003] At present, the flue gas denitrification technologies that have been practically applied in power plants in my country mainly include selective catalytic reduction (SCR) technology, selective non-catalytic reduction (SNCR) technology, and selec...

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Problems solved by technology

Urea direct injection technology also has major disadvantages: due to the lack of space at the tail of the boiler, urea is sprayed on the heating surface of the boiler before it is completely decomposed, and the urea droplets will cause corrosion on the heating surface after a long time; Affected by heat and heat exchange equipment, urea is directly injected into the flue at the end of the boiler, and cannot be uniformly mixed with flue gas, and urea cannot be completely decomposed in the flue, and is easy to crystallize on the catalyst and air preheater, resulting in blockage of the catalyst, air preheater and catalyst failure

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