Exhaust heat boiler and method for cleaning ash of exhaust heat boiler by using steam

The invention relates to an exhaust heat boiler and a method for cleaning ash of the exhaust heat boiler by using steam. The exhaust heat boiler comprises an observation door, a ventilation opening, a blower and a fume extractor, wherein 2 to 4 steaming vents are formed in front of a slag stopping screen at the inlet of the boiler; the steaming vents are communicated through steaming pipes; and each steaming pipe is provided with a valve. The method for cleaning ash by using steam of the exhaust heat boiler comprises the following steps of: a, controlling the temperature of the exhaust heat boiler to be between 100 and 200 DEG C, and closing all the observation door, the ventilation opening, the blower and the fume extractor; b, introducing steam from the steaming vents 2 in front of the slag stopping screen at the inlet of the boiler, wherein the steam is low pressure steam of between 0.4 and 0.8 MPa, and the flow per hour is between 3 and 6 t/h; and c, vibrating for 5 to 10 minutes when the steam is introduced at intervals of 1 hour, observing ash deposit conditions in the boiler, and introducing the steam for 20 hours. The exhaust heat boiler has reasonable structure and is insusceptible to secondary ash deposit. By the method for cleaning the ash, the problems of incomplete cleaning by manual and vibration ash cleaning methods, and quick ash deposition after secondary boiler opening, are solved, and the operating cycle of the boiler is prolonged.