Novozymes has launched Eversa Transform, the first commercially available enzymatic solution (a liquid lipase) to convert both glycerides and free fatty acids (FFA) into biodiesel. Biodiesel producers can thereby use cooking oil or other lower grade oils as biodiesel feedstock, reducing their raw material costs. The resulting enzymatic biodiesel is sold to the same trade specification as biodiesel created through traditional chemical processing.
Growing demand for vegetable oil in the food industry has resulted in increased prices, causing biodiesel producers to search for alternative—and more sustainable—feedstocks. Most of the oils currently used in biodiesel production are sourced from soybeans, palm or rapeseed, and typically contain less than 0.5% free fatty acids (FFA). Existing biodiesel process designs have difficulty handling oils containing more than 0.5% FFA—i.e., waste oils with high FFAs have not been a viable feedstock option.
The Eversa Transform reaction is carried out in a mixed batch tank operation. By controlling the reaction conditions, it is possible to ensure a minimum of FFA (typically around 2%) which is eliminated by a polishing step—e.g., a caustic wash step or a resin-catalyzed esterification.
|This figure shows the basic layout of the Novozymes enzymatic process. Recommended conditions for the enzyme reactor: 0.7% enzyme, 1.5 equivalent MeOH, 35°C/95°F, 2% water and 20 to 24 hours reaction time. Source: Novozymes. Click to enlarge.|
The enzymatic process eliminates the need for sodium methoxide, one of the most hazardous chemicals in traditional biodiesel plants. The significant reduction of harsh chemicals and by-products enhances safety for both personnel and the environment. The Eversa process does not use high pressure or temperature.
Eversa can work with a broad range of fatty materials as feedstock, but initial focus has been on used cooking oil, DDGS corn oil and fatty acid distillates.
The idea of enzymatic biodiesel is not new, but the costs involved have been too high for commercial viability,. Eversa changes this and enables biodiesel producers to finally work with waste oils and enjoy feedstock flexibility to avoid the pinch of volatile pricing.
The enzymatic process uses less energy, and the cost of waste oil as a feedstock is significantly lower than refined oils. A small number of plants have been producing biodiesel from waste oils using existing technologies. But this has not been cost-efficient until now, broadly speaking, as the waste oils have had to be refined before being processed using chemicals. We hope that our technology can unleash more of the potential in these lower grade feedstocks.—Frederik Mejlby, marketing director for Novozymes’ Grain Processing division
Two plants in the US—owned by Blue Sun Energy and Viesel Fuel—are using Novozymes enzymatic solutions for biodiesel production.
The process developed by Blue Sun for enzymatic transesterification improves the bottom line through lower costs and higher revenue.—Sean Lafferty, Vice President of Blue Sun Technology & New Business
Making the change from a chemical catalyst to the enzymatic process requires retrofitting in existing plants. Biodiesel producers looking to utilize Eversa will therefore have to invest time and resources to make the switch to the enzymatic process.
Novozymes’ engineering partners estimate that the resulting improved process economy indicates a payback time of three years or less, depending on the plant setup and feedstock savings potential in that region.