Rotary type air preheater and cleaning technique thereof

Abstract

The invention discloses a rotary type air preheater and further discloses a cleaning technique of the rotary type air preheater. The rotary type air preheater comprises a rotor with a heat storage element, a smoke channel is arranged on one side of the rotor, the upper portion of the smoke channel is used for guiding in of high-temperature smoke gas, and the lower portion of the smoke gas is usedfor guiding out of the high-temperature smoke gas. A secondary air channel and a primary air channel which are adjacent are arranged on the other side of the rotor, the lower portions of the secondaryair channel and the primary air channel are used for guiding in of cold air, and the upper portions of the secondary air channel and the primary air channel are used for guiding out of hot air. The rotor sequentially passes through the smoke channel, the secondary air channel and the primary air channel in rotating, a steam heater capable of stretching out and drawing back in the radial directionof the rotor is arranged on the lower portion of the rotor, and the steam heater is arranged at the bottom of the primary air channel and is close to the smoke channel, an inlet of the steam heater is connected with externally-arranged steam supplying equipment through a valve, a spray nozzle is arranged at an outlet of the steam heater, and the spraying direction of the spray nozzle is the sameas the flowing direction of air in the primary air channel. According to the rotary type air preheater and the cleaning technique, ammonium bisulfate online removal can be effectively achieved, and the heating efficiency and safe operation are ensured.

Description

technical field [0001] The invention relates to the field of coal-fired boiler equipment, more particularly, to a rotary air preheater and a cleaning process thereof. Background technique [0002] In thermal power plants, the emission concentration of nitrogen oxides in the flue gas of coal-fired boilers often needs to strictly comply with national standards. Therefore, thermal power plants generally need to install a denitration system to meet the emission requirements of national standards. In the denitration process, the selective catalytic reduction method (SCR method for short) refers to the use of NH3, liquid ammonia, urea and other reducing agents to selectively react with NOx in the flue gas under the action of a catalyst to generate non-toxic and non-toxic Polluted N2 and H2O) have been widely used in coal-fired power plants due to their simple process, high denitration efficiency, mature technology, and stable operation. During the use of the selective catalytic r...

AI Technical Summary

Problems solved by technology

[0004] SCR denitrification is to use ammonia and nitrogen oxides in flue gas to react under certain conditions to generate N2 and H2O and then discharge them into the atmosphere. However, during this process, the amount of ammonia injected cannot be precisely controlled, and ammonia escape is inevitable. The escaped ammonia will react with SO3 in the flue gas to form ammonium bisulfate, which is a highly viscous liquid substance in the range of 147-207°C

In this way, when the SCR denitrification flue gas passes through the air preheater, the liquid ammonium bisulfate is easily bonded to the wall plate of the low-temperature section of the heat storage element and continuously absorbs the dust in the flue gas. In this way, it is easy to cause the air preheater to If measures are not taken in time to remove the blockage, the heating efficiency of the air preheater will be reduced, the ventilation will not be smooth, and even the safe operation of the boiler will be affected in severe cases.

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