1) What is DW-R™ Dry Wash Resin?
DW-R™ is a dry ion exchange resin designed to remove salts, soap, catalyst, glycerin and water from raw B-100.
2) What are the physical properties of DW-R™ Dry Wash Resin?
DW-R™ consists of tough spherical beads with an average particle size of 400 microns (dry), and a range of 200 microns to 800 microns. It weighs 6.7 pounds per gallon, or 50 pounds per cubic foot (dry). Note! The individual beads will swell to more than twice their size when exposed to water or glycerin. It is very important to allow for this expansion to avoid rupture of vessels and other containers.
3) At what point in my process should DW-R™ be utilized?
DW-R™ is applied after phase separation. It can be applied before or after demethylation.
4) How do I decide whether to use DW-R™ before demethylation, or after demethylation?
You should base your decision on glycerin levels.
If glycerin is greater than 1,000 PPM (<0.1%) after demethylation, your DW-R™ will reach its maximum loading of glycerin before it reaches it maximum capacity for salt and soap. In this circumstance you should locate your DW-R™ columns before demethylation. You should then consider using a methanol wash to remove the glycerin from the DW-R™. The “dirty methanol” can be returned to the front of your process to avoid waste. (A complete procedure for a methanol wash can be found in Application Bulletin D.) By using the methanol wash procedure, you can restore your DW-R™ absorption capacity repeatedly until its salt capacity is exhausted.
If glycerin is less than 1,000 PPM (>0.1%) after demethylation, you may not be able to justify the effort required for a methanol wash. In that case, the DW-R™ is typically applied as a final polishing step after demethylation. If DW-R™ will be utilized at this location, it may prove more economical to use DW-R 8 instead of DW-R10. DW-R8 has 20% less ion exchange capacity than DW-R10, but it has the same capacity for glycerin and water. It is less expensive, and consequently may deliver a lower use cost when glycerin/water is the limiting factor.
5) What flow rate is the recommended flow rate for B-100 through my DW-R™ resin?
You should set a maximum flow rate of three bed volumes per hour for systems where the glycerin averages less than 1,000 PPM (<0.1%). If glycerin is greater than one thousand PPM (>0.1%), you should set the flow rate at 1.75 bed volumes per hour. These flow rates are for the lead column.
6) How much B-100 can I purify before my DW-R™ is exhausted?
As everyone knows there are a number of factors that affect B-100 contaminant levels. These include the completion of upstream reactions, effective phase separation and feedstock quality. For a well run system, with an average of 500 PPM of hydroscopic contaminants, you should expect to purify between 1,500 and 2,000 pounds of B-100 with each pound of DW-R™. Beyond optimizing upstream reactions and separation, there are some other measures that you can take to get the maximum production from your DW-R™ media. First you can use a lead/lag configuration to allow full exhaustion of the media without producing off-spec B-100. Second, you can use a methanol wash when your DW-R™ is applied prior to demethylation .