燃料油添加剤によるLNG船ボイラの汚損防止

-燃料油添加剤による残渣油の有効利用

抄録

Consumption of residual fuel oil in the main boiler of LNG tankers has been increasing due to a change in the design of BOR of the LNG tank or the use of a BOG re-liquefier. As a result, the ash part (Vanadium, etc.) in the residual fuel oil has also been increasing. These conditions make it easy to generate large quantities of fuel ash with a low melting point. The melt ash causes damages like sticking deposits, corrosion, etc. in the furnace and the superheater tube.
This report is intended to investigate a plan to prevent the above mentioned damage of the main boiler of LNG tankers by fuel oil additive.
The results of the comparison of fuel oil additive are as follows:
(1) As a result of having compared Si type additive with Mg type additive, Si type was confirmed to have a better effect on raising a softening point of V, Na compound in the range of 300-500 degrees Celsius than Mg type.
(2) Si type additive inhibits high temperature corrosion in the same way as the Mg type additive.
(3) When Si type additive is added to fuel oil with 1.2-3.6 times of the V, Na gross weight, the adhesion inhibition rates of fuel ash decrease by 30-70%.
These effects will be able to maintain high thermal efficiency and longer safe operation of the main boiler.