Saturday, May 17, 2008

General Information on Crude Glycerin Byproduct

Excerpted from Renewable Energy Online:
Crude glycerol is not a valuable product and currently sells for about 1 to 2 cents per gallon. For every 100 pounds of biodiesel produced, 10 pounds of glycerol is also created.

...Traditionally, glycerin has been used to produce nitro-glycerin and soap. But crude glycerin can also be burnt, composted or fed to ruminants. Research on turning glycerin into an alternative to antifreeze is also within grasp.

Burning glycerin for heat and power can render positive effects, however, temperature is a significant concern. Burning [ed: crude] glycerin at temperatures between 200 and 300°C (392-572°F) emits toxic acrolein fumes so temperatures beyond 1,000°C (1832°F) are necessary.

As a sugar, glycerin can be a considerable addition to compost. This is a much simpler option. However, it is important to make sure the glycerin does not cut out oxygen and negatively affect pH, which harms the composting bacteria. Glycerin is also a liquid and therefore hard to contain. Since it can be harmful to ground and surface water, it is vital to prevent leakage.

...A third option is to feed the crude glycerin to ruminants. In actuality, there are no regulations that affect the use of glycerol as a feed additive. The overall consensus is that crude glycerol can comprise up to 15 percent of a ruminant animals diet and 15 percent of pelleted feed mix. Dairy cows are the exception where a study found the limit to be 1 to 5% with an improvement in energy balance when glycerol comprised 2% of their diet.

Assuming the crude glycerin is 80% pure glycerin, Brett Hess from the University of Wyoming thinks that crude glycerol should sell at 89% of the price of cornstarch. This would give it a price of 1 to 2 cents per pound or 10 times current market value. However in most cases, crude glycerin is 50 to 60% pure and thus should be discounted 33%.

The two other product options for glycerin, making hydrogen or propylene glycol, are still in the research phases. Since the process is complicated, when and if it becomes technologically mature, it will likely be done in centralized plants. This basically means small biodiesel producers will probably only need to invest in storage and sell their glycerin much like a lot of restaurants are selling their waste oil.

The other upcoming use for glycerin is propylene glycol. It can be used as a non-toxic anti-freeze, coolant, or deicer. Although petroleum based ethylene glycol is currently much cheaper, it remains a non-renewable resource that is highly toxic and as such is bound to lose popularity.

More information in the "resources" section here.

As the quantity of produced biodiesel is ramped up, it will be more important to find profitable uses for byproducts such as glycerin, which are up to 10% of biodiesel production by weight. If the value of crude glycerin is to go up between 5 and 10 times its current price, that would represent a significant price adjustment, and should be accounted for by all business interests contemplating using glycerin as a feedstock.



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