Rotary air preheater

A rotary air preheater, comprising:

• a rotor rotating around a central sleeve;
• a flue gas section;
• a primary air section and a secondary air section being arranged within the rotor in a circumferential direction, wherein the flue gas section, the primary air section, and the secondary air section being spaced, and a heat exchange element being arranged on the rotor;
• and
• a steam soot-blowing device arranged in a cold secondary air inlet channel of the secondary air section, wherein the steam soot-blowing device comprises a steam sootblower, a first pipe communicating with the steam sootblower and extending in a radial direction of the rotor, and a nozzle assembly communicating with the first pipe;
• wherein the nozzle assembly comprises a first nozzle assembly and a second nozzle assembly, the first nozzle assembly located upstream of the second nozzle assembly in a rotational direction of the rotor;
• wherein the first nozzle assembly comprises a throttle pipe with one end communicating with the first pipe, and a sprayer communicating with the other end of the throttle pipe, a throttle shrinkage hole is provided inside the throttle pipe, a diameter of the throttle shrinkage hole is smaller than a diameter of the throttle pipe, and a diameter of an inlet of the sprayer is smaller than a diameter of an outlet thereof;
• wherein the second nozzle assembly comprises a distribution pipe communicating with the first pipe, and at least one nozzle communicating with the distribution pipe, and a steam jet velocity at the outlet of the sprayer is smaller than a steam jet velocity at an outlet of the at least one nozzle.