Advantages Of Bio Diesel Drywash Method
In the US, fuel-grade biodiesel must meet or exceed the purity requirements of the ASTM D6751 standard and must be legally registered with the Environmental Protection Agency (EPA). Today, the bio diesel drywash method of neutralization of contaminants in the fuel ensures the highest quality of biodiesel purity.
Methyl esters and glycerin are by-products of biodiesel manufacturing. They are detrimental to engines. They must therefore be removed from the biodiesel produced through the transesterification process.
Biodiesel was earlier purified through use of a spray of fine water mist over the biodiesel, the wet method's distinct characteristic. It had many disadvantages. Two of them were increased production time and increased cost of production.
Today, the world has mostly switched over to the drywash method of biodiesel purification. In the drywash method, the water mist is replaced by magnesium silicate powder. The latter is used to neutralize the contaminants in biodiesel. There are many advantages of the drywash method of biodiesel purification over the wetwash method. They are given below. The drywash method using magnesium silicate decreases production time. This is because in comparison with the water mist spray method, it takes just a few hours for the biodiesel to become ready for use. It further helps to lower cost of biodiesel production. This is because water is costly to remove in the wet wash method. It requires costly water removal equipment. It forms one of the largest costs of production. All this is not required to be done when the drywash method is used. Further, water removal equipment (mostly water wash tanks and water settling tanks) takes a large amount of space in the wet wash method. This space is saved in the drywash method. High quality biodiesel is produced through use of the drywash method. This is because no water is added to biodiesel in the drywash method. Therefore, the water content in purified biodiesel, produced using the drywash method, is less than 500 ppm (parts per million). This conforms to the requirements laid down in ASTM D6751. Another advantage of the drywash method is that magnesium silicate is reusable as an animal feed additive. It is also used as compost. It has potential as a source of fuel. Resin is used to purify biodiesel instead of magnesium silicate in a variant of the drywash process. However, the biodiesel yields (250 to 380 liters) are comparatively less than in the drywash method. Further, the quality of the biodiesel is not as good in the resin method as in the drywash method. It is possible to switchover from the wetwash method to the drywash method. This is made possible by a cost-effective redesigning of the water tanks used in the former to the drywash method. Even though the bio diesel drywash method of biodiesel purification is capable of meeting the biodiesel purity requirements entailed by ASTM D6751, monitoring the levels of contaminants is always recommended.
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