Fatty acid methyl esters were prepared by esterification in a fixed bed reactor from methanol and fatty acids in palm oil deodorizer distillate (PODD) using a cation exchange resin as catalyst.

The working process of resin bed and working principle of acid purification unit and flowchart are described particularly. Making comparison of acid consumption of using it before and after.

Another problem with demineralizers is that small resin particles are often dislodged from the bed and enter the water stream.