[?] Subscribe To
Before we start discussing biodiesel dry wash systems, we need to categorize the various generations of washing system designs.
First-generation wash systems used water to wash the biodiesel. Water washing is a very simple and effective method of purifying biodiesel. The only disadvantages to water washing are that it takes time and that the wash water becomes contaminated. In many cases, a water wash system is the best solution. Water washing is also a lot cheaper than comparable dry wash systems.
Magnesol was one off the first dry wash systems that was introduced, and it is manufactured by the Dallas Group. Magnesol is a synthetic Magnesium Silicate and is very effective at removing soap from biodiesel. The main issue with using Magnesol is that the particle size is very small and it is quite difficult to filter the Magnesol from the biodiesel once it has been introduced
Magnesol is very easy to use. The biodiesel is settled and the glycerol drained off, a fixed amount of Magnesol is added and the biodiesel and Magnesol are mixed together. The Magnesol is then removed by settling and filtering. Any used Magnesol is then disposed of.
Second-generation wash systems typically comprise of ion exchange resins. Amberlite and Purolite are typical ion exchange systems. Both of these resins do a good job of removing soaps and trace amounts of glycerin. However, it is important when using an ion exchange resin that as much glycerin is removed as possible before it is used. Failure to do this will result in the resin becoming saturated.
Another second-generation wash system, although it is not strictly an ion exchange resin, is manufactured by Lenaxis and is designated Lewatit GF202 or SP112. This product, has the advantage of being able to be regenerated and is probably the most cost-effective option when it comes to ion exchange resins. Lenaxis manufacture an entire range of special resins which can be used from the beginning to the end of the biodiesel process.
Eco2pure is another dry wash system, which is manufactured from wood chips mixed with a molecular sieve.
All of these second and third generation biodiesel dry wash systems require specially designed columns in which to place the chemicals. In addition, unlike wet wash systems they do not remove methanol from the biodiesel. This means that provision has to be made for methanol removal before or after the dry wash.
In my experience the main reason that biodiesel, which is washed in a dry wash system fails a lab test is that the methanol is not removed adequately. This is not a failure in the dry wash chemicals but rather a failure in plant design.
There are more and more dry wash systems appearing on the market as the biodiesel industry mushrooms. It is probably not possible to keep a complete list of them.
If you are a manufacturer of dry wash chemicals, please drop me an e- mail : dry @ home-made-biodiesel.com and I will be happy to include your product on the list.