Investigation on drying of middle distillate by Pervaporation

The drying of middle distillate (MD), from which diesel fuel is made, by Pervaporation (PV) was experimentally investigated in a laboratory plant applying organic membranes. The work was conducted in cooperation with a refinery in which MD is catalytically desulphurized by hydrogenation. The H2S formed is separated by steam stripping. The resulting water content in the MD is removed by decanting and subsequent vacuum drying. The objective was to investigate whether drying to low ppm water content is technically possible by the process of PV and to find out about the feasibility of replacing the vacuum drying by PV to save energy. The drying to low ppm water content was accomplished successfully. Permeate total and pure water fluxes are reported. Economic estimations compared vacuum drying costs taken from an existing plant with a design for a full scale multi-module PV plant. The run time of a plant for the point, at which energy savings make up for higher investment costs is estimated.