For a continuous process, it is recommended to install two columns to eliminate downtime when replacing spent resin. Please note that introducing a second column will not impact your consumption of Amberlite BD10DRY. The two columns are switched by valves to alternate between "lead" and "lag" treatment positions.

A Rohm and Haas Technical representative will work with you to select a column design best suited to your process.

A column design sketch based on 10 MM gallons (37.8 MM liters) per year throughput is enclosed.

CAUTION! Amberlite™ BD10DRY™ technology is designed to be used in a water-free process. The polymer beads will swell to up to 3 x their original volume as they absorb water. The beads will also swell over their life cycle as they remove impurities, including methanol and glycerol. It is therefore strongly recommended to leave sufficient void space in the columns.

Extra glycerol removing capacity

Even higher capacity for glycerol can be achieved by adding one or two extra columns of Amberlite™ BD10DRY™ media dedicated exclusively to glycerol removal, as shown in the following figure.

These additional glycerol removal columns are inserted just after the phase separation step. Note that the Amberlite™ BD10DRY™ media purchased for these columns will not impact your overall resin consumption. Why? Because when the glycerolremoval columns are initially installed they will remove not only glycerol but also catalyst and soap. Therefore consumption of resin in the downstream purification columns will be saved.

When the media in a glycerol removal column is saturated with glycerol, the column can be regenerated by rinsing with methanol. The methanol solution coming off the column can then be sent back to the transesterification unit where the methanol is recycled. The interest in having two columns dedicated to glycerol removal is that the plant can continue to operate while the first column is being regenerated. These columns can thus be regenerated several times to reestablish their glycerol removing capacity. However their capacity to remove soap and catalyst is finite; in the steady state of operation they will only serve to remove glycerol. Under industrial conditions, the Amberlite™ BD10DRY™ media in the glycerol columns is usually replaced from time to time by the spent resin in the downstream purification columns.