Fatty acids Esterification
The Davy esterification system is a simple continuous process that is used for esterification of natural and petrochemical acids. the process uses reactive distillation to produce an ester product that can be hydrogenated directly without any further processing. The solid resin catalyst is retained on the reaction trays, and so does not contaminate the methyl ester product. The catalyst can also be replaced while the plant is online.
Methyl esters are pumped to the hydrogenation reaction pressure of around 40 bar and fed into the hydrogenation vaporiser. The feed liquid is vaporised by a hydrogen-rich gas stream which passes up through the vaporiser.
The overheads from the hydrogenation vaporiser are fed to the hydrogenation reactor containing a fixed bed of catalyst. The reaction occurs in the vapour phase in a stream of excess hydrogen. The mild operating conditions of the Davy hydro-genation process along with uniform temperature and short residence in the reactor results in a very highly selective process. This high process selectivity results in minimal byproduct formation and hence high quality endproducts.
Fatty Alcohol Refining
Unconverted esters are separated and recycled back to the hydrogenation section. Residual methanol is recovered and recycled, and a light ends purge is taken if necessary to achieve the required product alkane specification. The column is run under vacuum and a falling film vaporiser used for the reboiler to prevent thermal degradation of the product. Heavy boiling bottom stream is recycled back to the hydrogenation section.
Post-Hydrogenation of Fatty Alcohols
The post-hydrogenation system converts any trace carbonyls that are present in refined product to alcohol. The continuous plant operates with a fixed bed catalyst reactor fed with the refined product and hydrogen. The proper design of the reactor system ensures uniform operating conditions and long catalyst lifetime.
Fractional Distillation of Fatty Alcohols
Fractional distillation systems for Fatty Alcohols are typically designed as add-on unit operations to produce high purity single alcohol cuts. The single or two tower systems are fitted with high performance structured packings for minimal pressure drop and highest product quality. Condensation is performed by internal shell and tube condensers or pump around internal packed section with external cooler. Canned pumps with falling film reboilers or centrifugal pumps with suppressed vaporization reboilers are used for heat input.