Urea hydrolytic and pyrolytic compound ammonia preparation system for denitration in thermal power plant

Abstract

The invention discloses a urea hydrolytic and pyrolytic compound ammonia preparation system for the denitration in a thermal power plant. The urea hydrolytic and pyrolytic compound ammonia preparation system comprises a urea solution inlet pipe, a hydrolytic reactor, a decarbonization tank, a desalted water pipe and an exhaust fan, wherein the urea solution inlet pipe is communicated with an inlet in the side surface of the hydrolytic reactor; the bottom of the hydrolytic reactor is provided with a steam heater for heating a urea solution in the hydrolytic reactor; a top outlet of the hydrolytic reactor is communicated with a bottom inlet of the decarbonization tank; a desalted water inlet in the side surface of the decarbonization tank is communicated with the desalted water pipe; the exhaust fan is located at a top opening of the decarbonization tank; a bottom outlet of the decarbonization tank is communicated with an ammonia water pipe. The system is low in energy consumption; a product cannot block a pipeline; moreover, the cost is low.

Description

technical field [0001] The invention relates to an ammonia production system, in particular to a urea hydrolysis pyrolysis composite ammonia production system for denitrification in a thermal power plant. Background technique [0002] The flue gas emitted by coal-fired power plants contains a large amount of nitrogen oxides and needs to be purified. At present, the flue gas denitrification technology widely used is based on ammonia (NH 3 ) as a reducing agent, reducing NOx to non-toxic and harmless nitrogen (N 2 ). For safety considerations, the preparation of ammonia in thermal power plants is based on urea (CO(NH 2 ) 2 ) as raw materials, divided into two technical routes of low-temperature hydrolysis and high-temperature pyrolysis. The urea solution undergoes a hydrolysis reaction below 200°C, and the reaction equation is: [0003] NH 2 CONH 2 +(1+X)H 2 O→2NH 3 ↑+CO 2 ↑+(X)H 2 O↑ [0004] In practical engineering applications, the product gas only contains 28...

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Problems solved by technology

[0007] Compared with the two processes, urea hydrolysis has the advantage of low energy consumption (low reaction temperature), but the product pipeline has the risk of corrosion and clogging, and requires full heat tracing, which increases energy consumption; urea pyrolysis has rapid response, and the pipeline does not need heat preservation , no pipeline blockage, etc., but the cost of the pyrolysis furnace is high, and additional fuel will be consumed to reach the reaction temperature. After a long time of use, impurities will agglomerate in the lower part of the furnace, which will affect the stability of use.

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