The exhaust gas cleaning device (closed-loop fresh water SCRUBBER) and the NOx reduction apparatus of EGR (Exaust Gas Recirculation) the sulfate contained in the contaminated wash water (H ₂ SO ₄₎ and sodium hydroxide (2NaOH) of SCRUBBER a chemical reaction for the ship's engine If by sodium sulfate (Na ₂ SO ₄₎ salt is generated continues for a washing cycle the salt concentration increases, thereby increasing the amount of residue, such as soot.
This there is a precipitate when the wash water contaminated in order to increase the cleaning effect to cause the tree to fall the cleaning effect of SCRUBBER 1, second cooling 10 beard sodium sulfate _{(Na 2 SO 4. 10H 2} O) to the more the temperature is lowered solubility suddenly a large amount of low sodium (Na ₂ SO ₄₎ the salt is precipitated.
Separating the precipitated salt and agglomerated combustion residues by centrifugation over sodium sulfate of the wash water (Na ₂ SO ₄₎ can be taken out by reducing the salt concentration and contamination (Bleed off water) as makeup water to reduce the amount of (Make-up water) there is an advantage that reduces the economic advantages and problems of the limited space available on ships.