How to Remove the Dust Coking and Slag in a Thermal Fluid Heater
1. Soot Blowing
If there are fuel gas dust remains in the thermal fluid heater, it will increase the thermal resistance area and effect the thermal heat transfer efficiency. Operator should blow and clean the inside of heater from time to time.
To blow and clean the dust by steam is not recommended, because there are water contains in the steam and water will make dust into mud, mud sticks to the heaters and the situation will become worse.
We suggest operator to blow and clean the dust by compressed air, normally thermal fluid heater works with soot blower.
In the radiant heating surface, there are molten slag stains. Because this area is the hottest area in the thermal fluid heater, the coking slag is normally soft and molten condition. The coking slag is dangerous because it not only effect the thermal efficiency and also may cause explosion.
Coking slag also make the tubes weak.
Why there are coking and slag? It could caused by many reasons
1. Unreasonable furnace structure.
2. Low ash fusion point of the fuel.
3. Flame center excursion.
Operator should check the thermal fluid heater working condition to try to avoid these problems.
3. Chemical Cleaning
Coal fired thermal fluid heater normally use alkali metal nitrates mixed with combustion improver or disperser as the chemical cleaning materials.
Oil fired thermal fluid heater normally use ammonium salt mixed with activator or additive.
When the thermal fluid heater is working, the heated chemicals will release alkali metal cation to cover the heated surface, it will stop the dust deposition.
It also produce melt nitrate to active with the coking slag to make the slag loose, crisp and easy to fall off the tubes.
Chemicals also has the function of combustion supporting. It will improve the thermal efficiency and reduce the pollution.
To avoid coking and slag generated, operator should control the exhaust gas temperature under 850℃, soot blower equipment is necessary. Operator should fill the chemical dust remover every 2 weeks or as required. The tubes in thermal fluid heater must be clean.