Dr Idan Chiyanzu.

Camelina (Camelina sativa L.) is an ancient oilseed crop that has been used as a food with gigantic potential for biodiesel production and animal feeding. It originated in Central Europe and Asia, where it is well adapted to cool temperate semi-arid zones. Currently, the crop is grown in many parts of the world including Europe, Canada and the Northern USA, where farmers are generating their own energy from it.

Interestingly, this crop is low-input, high-yielding oilseed containing between 36% and 47% total oil, 34% to 36% Omega-3 oil and is high in δ-tocopherol, a vitamin E that acts as an antioxidant. Antioxidants in oils are vital because they give the oil a longer shelf life, making it a superior candidate as feedstock for biodiesel production. Furthermore, camelina has a comparatively short growing season of 80 to 100 days, requiring no specialised equipment to harvest. The leftover forage after processing is often fed to livestock, pigs and poultry.

Camelina Sativa

During its cultivation, yields of camelina seeds are in the range of 1.5-3.0 tonnes per hectare (t/ha) and can yield as much as 370 litres of oil and roughly 1 tonne of oil cake. The crop can grow in both winter and summer. Many farmers consider camelina a replacement for off-season farming periods, and the crop that can be used in rotation with other crops. Camelina is adapted to various climatic conditions (including marginal lands), has low nutrient requirements and good resistance to diseases and pests. Because of these positive agronomic and environmental features, it has contributed to an increased interest of many scientists and farmers in extending the use of camelina to other areas such as food, nutraceuticals, paints, dyes, cosmetics and biodiesel manufacturing.

Biodiesel production from Camelina sativa oil

In Europe, North America and Canada, camelina is predominantly used to generate on-farm biodiesel. Biodiesel is an alternative fuel that can be made from a variety of oils, fats and greases, and may be of interest to farmers in South Africa for a number of reasons:

  • The sale of biodiesel can provide an additional income to the farmer.
  • It can allow farmers to make the fuel they need for farm machinery; and it can decrease South Africa’s dependence on imported crude oil as fuel raw materials can be grown domestically.
  • Being a cleaner-combusting fuel, it is both user-friendly and environmentally-friendly.

Processing oil into biodiesel

Biodiesel can be made simply by activating vegetable oil or animal fat with an alcohol and a catalyst. This process is accomplished with normal heating, microwave or ultrasonic radiation coupled with mixing to yield biodiesel and crude glycerol. The chemical name for the process is ‘transesterification’ and is relatively a straight-forward process.

Ultrasonic setup for biodiesel production at the ARC-Institute for Agricultural Engineering, Silverton, Pretoria.

Transesterification is a name given to a simple process of combining a chemical compound called an ester and an alcohol to make another ester and another alcohol.

100kg Oil + 10kg Alcohol Û 100kg Biodiesel + 10kg Glycerol

  • Recommended catalyst in small amount is potassium hydroxide or sodium hydroxide
  • Recommended alcohol is methanol or ethanol

Since the biodiesel, that result from this reaction can contain numerous contaminants such as soap, catalyst and alcohol; it normally requires further processing to remove these contaminants. Washing biodiesel with hot water is the most common method of cleaning biodiesel. It normally takes several washes to clean the impurities in the biodiesel and enable it meet fuel-grade standards. However, in order for the biodiesel to be used in a diesel-powered engine, it needs to meet the South African National Standard (SANS) 342:2016 fuel quality standards for biodiesel. Using biodiesel that does not meet this standard risks damaging the diesel engine and users may lose engine manufacturer warranties.

Storage of biodiesel

Biodiesel should always be kept in a cool, clean, light-proof container that is filled to the top and semi-sealed, allowing minimal air exchange to prevent pressure build-up. Biodiesel should not be stored or transported in metal containers such as copper, brass, bronze, lead, tin or zinc as these metals will hasten degradation of the fuel. Acceptable materials and equipment for pure biodiesel storage include Teflon, Viton, fluorinated plastics and nylon or those compatible with materials used in diesel fuel systems after 1993.

Note: If biodiesel is to be stored for longer than about six months, a stability additive should be used, especially in tropical and sub-tropical regional climates, due to increased temperature and humidity. – Dr Idan Chiyanzu, ARC

For more information on biodiesel production opportunities and training, please contact:

Dr Idan Chiyanzu at chiyanzui@arc.agric.za

 

 

 

 

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