Sootblower

Soot-blowers are mechanical devices used for on-line cleaning of gas side boiler ash and slag deposits on a periodic basis. They direct a cleaning medium through nozzles against the soot or ash accumulated on the heat transfer surface of boilers to remove the deposits and maintain the heat transfer efficiency.

Steam for soot-blowing may be taken from intermediate super-heater headers, cold reheat inlet headers, secondary super-heater outlet headers or hot re-heat outlet headers. Each source has advantages and disadvantages, often complicated by the boiler operating mode, i.e., constant, hybrid or variable pressure.

Wall Sootblower
For some lignite and subitominous coal having severe slagging or reflective ash deposit.The blowing element retract from the boiler when not in use to protect it from the effect of flue gases at high temperature.



Retracting wallblowers are used to control the build-up of slag and ash deposits on furnace water wall tubes. The control of slag and ash deposits on the furnace water walls is very important, because most of the steam is generated in the furnace water walls. Water wall tube cleanliness must be kept in the normal range to ensure that the design performance of the boiler is not affected.

The retracting wallblowers are short travel, retracting blowers, rotating 360º and blowing through a predetermined arc controlled by the length of a cam.



Long Retract Sootblower.
The pendant superheater and reheater sections, as well the convection section of horizontal tubes, are cleaned by long retractable sootblowers.
This sootblower is designed for the removal of slag and deposit from furnace tubes and superheater
This sootblower is designed for effective cleaning of heating surface in elevated gas temperature zones of boiler and other heat exchanger.

The retractable and extended lance sootblowers are used to remove smelt, slag and ash deposits from generating tubes, slag screens, superheaters, reheaters, and economizers. They are also used to clean deposits from the underside of the furnace arches.

The retractable and extended lance sootblowers clean the heating surfaces by multiple impacts of high-pressure steam from nozzle openings located at the end of a long lance tube. During operation this lance is rotating while being extended and retracted through the cleaning area.


The sootblowing cycle begins with the blower in the retracted position. When power is supplied to the drive motor, it moves the carriage along the guide rails located on each side of the beam to project the lance tube into the boiler. When the nozzle is inside the boiler, the carriage will trip a linkage that opens the poppet valve to begin the cleaning cycle. The carriage will continue to extend and rotate the lance tube into the boiler until it reaches the extreme forward travel. At this point, the carriage will reverse its direction and at the same time index the lance tube to return on a different nozzle path.

The carriage will continue to retract until the nozzle is near the boiler wall at which point the poppet valve is closed thereby stopping the steam flow. The carriage then continues to the retracted position and stops.


Picture below describe soot-blower system completed with set pressure control valve and thermal drain control valve. Pressure control valve maintain line soot-blower to 34Barg and line temperature 260C. Also T-s diagram to see soot-blower process.