We design and manufacture biodiesel polishing skid systems for biodiesel from dry wash processing. We have constructed several biodiesel polishing skids of various hydraulic capacities which are presently available for immediate sale and installation. These biodiesel polishing skids use Lanxess Sybron GF-202 resin to polish biodiesel from dry wash processing. Other capacity systems can be built to match client requirements.

The processing capacities of these stock biodiesel polishing units are 7-10, 30 and 45 million gallons per year of BD-100 product. A picture of the smallest biodiesel polishing skid can be seen here.

Typical of our biodiesel polishing skid systems, our 7 to 10 million gallon per year biodiesel polishing system has been designed and fabricated as a continuous biodiesel system in a skid-mounted configuration. The biodiesel polishing skid consists of a 2-bed adsorption system with guard filtration and controls utilizing Lanxess Sybron GF-202 polishing resin. The hydraulic capacity of this biodiesel polishing package was designed for 10 million gallons per year (7 cubic meters of resin) of biodiesel throughput.

Lanxess Sybron GF-202 resin is a mono-dispersed, homogeneous adsorption resin that comes in spherical form laden with water. Because of shipping weight considerations, the resin must be installed in the polishing system following assembly of the system on the client site. The resin is loaded into the polishing vessels via the top manway after partial water fill to assist with the packing and dispersion of the resin in a bed. Once the vessels are filled, water is drained and methanol is used to purge excess water and allow the resin to function in biodiesel service.

GF-202 resin is part of a program to process biodiesel without the use of water wash following the transesterification reaction step in the production process. Prior to polishing biodiesel, the product is neutralized to reduce catalyst activity, glycerol is physically separated from the reaction effluent and methanol is removed. In some biodiesel processes winterization is required to reduce cloud point and cold soak filtration processing issues.

During the glycerol separation process, small amounts of glycerol remain in the biodiesel product. Also remaining in the biodiesel are small amounts of soap and salt catalyst residue. As biodiesel is polished in the two polishing beds, the glycerol is adsorbed on the surface of the GF-202 resin. Soap and salt having a higher affinity for glycerol than biodiesel also adsorb on the surface of the GF-202 resin. Small amounts of trace methanol in biodiesel also are adsorbed without effecting resin performance. The biodiesel effluent from the polishing system has been polished to meet sales specifications for biodiesel in regard to sulfonated ash and glycerol content.

Once the resin is saturated with glycerol, the resin bed must be taken off-line and regenerated with methanol. The regeneration methanol is collected for reprocessing in the transesterification section of the plant. During regeneration, the biodiesel process continues to operate in a single-bed adsorption process. This feature of the skid design is the primary reason for the lead-lag configuration of the two-bed system with remote actuated valves. Following regeneration the bed is drained, purged, methanol eluded back to devolatilization and then placed back into biodiesel service as the second bed in the polishing train.

While the Lanxess Sybron GF-202 resin improves the finished quality of biodiesel, it does not remove the need to properly pretreat biodiesel raw material coming into the transesterification process. It is not intended to remove materials like proteins, sterols, starches, tocopherols, tocotrienols, sulfates, sulfonates, metals, and phospholipids that are removed by other processing steps in a properly designed biodiesel plant. It cannot improve cloud point issues caused by saturated sterol esters produced in the manufacturing process.