Sootblowers

Soot blowers are cleaning devices used to remove ash deposits from the heat absorbing surfaces of the boiler. They are installed at locations which are susceptible to ash deposit. Most of the ash is usually deposited in regions downstream of the radiant section.

The ash characteristics and operational needs are considered when designing a soot blowing system.

There are three primary reasons why cleaning equipment such as soot blowers are required on a boiler:

a. Soot blowers improve heat transfer. A small amount of soot on any heating surface drastically reduces the heat transfer rate, and causes more fuel to be burned in order to produce an equivalent output. Every pound of soot causes a waste of fuel and sends unclaimed BTUs out the stack. For example, a soot layer 1/32” thick can reduce the thermal conductivity of the heating surface by approximately 10%. A soot layer 1/16” thick can reduce the conductivity by approximately 25%; a soot layer 1/8” thick can reduce the conductivity by approximately 45%; and a soot layer 3/16” thick can reduce the conductivity by approximately 70%.

b. Soot blowers control draft losses. Air flow handling capability of a boiler is adversely affected by soot deposits on or between tubes. This reduces airflow through some parts of the boiler while increasing it in others, upsetting the fuel/air ratio. An improper fuel to air ratio can cause improper combustion which wastes valuable fuel, increases fan horsepower and lowers boiler efficiency.