Describe the purpose and proper operation of sootblowers.

Sootblowers are devices used in boilers to remove soot and ash deposits that accumulate on heat transfer surfaces, maintaining boiler efficiency and preventing tube failures. Soot and ash deposits act as insulation, reducing heat transfer and increasing flue gas temperatures, leading to reduced boiler efficiency. These deposits can also cause corrosion and erosion of boiler tubes. Sootblowers use high-pressure steam or air to remove these deposits. There are two main types of sootblowers: retractable and stationary. Retractable sootblowers consist of a lance that extends into the boiler and rotates while discharging steam or air. Stationary sootblowers are fixed in place and direct steam or air onto the heat transfer surfaces. The proper operation of sootblowers involves several key considerations: 1) Frequency: Sootblowers should be operated frequently enough to prevent excessive buildup of deposits but not so frequently that they waste energy or cause tube erosion. The optimal frequency depends on the fuel type, boiler design, and operating conditions. 2) Sequencing: Sootblowers are typically operated in a pre-defined sequence to ensure that all heat transfer surfaces are cleaned effectively. 3) Pressure: The steam or air pressure should be high enough to dislodge the deposits but not so high that it causes tube erosion. 4) Coverage: The sootblower nozzles should be aligned and positioned to provide adequate coverage of the heat transfer surfaces. 5) Monitoring: The effectiveness of the sootblowers should be monitored by measuring flue gas temperatures and boiler efficiency. Increasing flue gas temperatures or decreasing boiler efficiency may indicate that more frequent or more effective sootblowing is needed. Regular maintenance of sootblowers is also essential to ensure their proper operation. This includes inspecting and repairing nozzles, valves, and drive mechanisms.