Liquid ammonia evaporator and liquid ammonia evaporation system for flue gas denitration

Abstract

The invention discloses a liquid ammonia evaporator and a liquid ammonia evaporation system for flue gas denitration, wherein the liquid ammonia evaporator comprises a heat exchange chamber and a stainless steel heat exchange pipe which is arranged in the heat exchange chamber; the heat exchange chamber consists of a lower heat exchange chamber and an upper heat exchange chamber; a denitrated flue gas inlet is arranged at the top of the lower heat exchange chamber and a denitrated flue gas outlet is arranged at the bottom of the lower heat exchange chamber; a hot air inlet is arranged at the bottom of the upper heat exchange chamber and a hot air outlet is arranged at the top of the upper heat exchange chamber; the stainless steel heat exchange pipe comprises a primary heat exchange pipe which is arranged in the lower heat exchange chamber and a secondary evaporator heat exchange pipe which is arranged in the upper heat exchange chamber; the pipe wall of the secondary evaporator heat exchange pipe consists of an inner wall and an outer wall; evenly distributed millimeter-level small holes are arranged on the inner wall; and evenly distributed micron-level micro holes are arranged on the outer wall, according to the liquid ammonia evaporator, the heat exchange efficiency of liquid ammonia is greatly improved and an ammonia evaporation supply system is simplified; and the liquid ammonia evaporation system has a compact structure and is capable of fully utilizing the waste heat of flue gas and the heat of preheated air.

Description

technical field [0001] The invention relates to a liquid ammonia evaporator and an ammonia evaporation supply system applied in the field of flue gas denitrification. Background technique [0002] Selective catalytic reduction (selective catalytic reduction) denitrification process is currently the main denitrification process in coal-fired power plants. Its principle is that under the action of a certain temperature and catalyst, the reducing agent selectively reduces NOx in the flue gas to non-polluting N2 and water. At present, the reducing agent used in industry is mainly ammonia, followed by urea. The use of ammonia as the reducing agent requires the use of an ammonia evaporation supply system, that is, the liquid ammonia is first evaporated into ammonia gas, then passes through the ammonia buffer tank, and then combined with air ( Conveyed by a dilution fan) mixed in the mixer, then enters the ammonia injection grid, and finally enters the catalytic reactor for reacti...

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Problems solved by technology

[0004] The purpose of the present invention is to provide a liquid ammonia evaporator and liquid ammonia evaporation system for flue gas denitrification with simple process and high heat exchange efficiency. Technical issues requiring additional steam or heat

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