Feed stocks that are used in the Second Generation are biomass which consists of
1) Residual non-food parts of current crops that are left behind after the food has been extracted:
· Hunks
· leaves
· stems
2) Non-food crops like:
· Switch grass
· Jatropha
3) Industry waste such as
· Pulp from paper making industry
· Skin and pulp from fruit pressing
· Forestry residues
· Restaurant wastes
· Wood chips
Production of Biodiesel from Renewable Resources
The increasing concerns over the sustainability issue of many First Generation Bio-fuels have raised attention to the so called Second Generation Bio-fuel. Generally, second generation of biodiesel is produced from lignocellulosic materials. This kind of raw materials can be considered as sustainable as it does not compete directly with our food. Furthermore, it has higher yields per hectare of land and requires lesser chemical and energy input in harvesting and production processes. However, there are still some debates over the non-food crops might compete with the food crops for arable lands and also fertilizer. Depending on the feedstock choice and the extraction method, Second Generation Bio-fuel offers a lot of benefits such as turn waste into resources and consumes lesser land. In this way, it promotes rural development and also improves the economy of developing country directly.
Second Generation Bio-fuel applies the concept of whole crop utilization. The large amount of agricultural waste after harvesting process such as stems, leaves and the hunks of the crops can be used as biomass and eventually being converted into Bio-diesel. By this method, not only we can make full use of the waste materials, the Bio-diesel produced also can be used to decrease the rate of depletion of natural resources. However, only one-third of the biomass can be harvested as the remaining portion needs to be kept on the field to maintain the fertility and prevent soil erosion. In addition to that, growing energy crops for the production of Bio-diesel prevent displacement from food chain and would have the effect of stabilizing the price of food as well as fuel in years to come. For certain industries like paper manufacturing factories, integrated use of waste to resource method can be implemented. For example, the pulp that is rich in cellulose can be converted to Bio-diesel and it can be channel back to the power plant for energy production for paper making process.
Jatropha Curcas-Feedstock for Bio-fuel in Future
Jatropha curcas has been put under intense spotlight due to its potential to solve the world’s energy crisis. Jatropha curcas is able to grow on arid or semi-arid land, especially on degraded lands which are usually considered as ‘lifeless land’. It is a hardy plant which is well adapted to harsh environment like deserted margins. Besides that, growing in harsh weather condition like drought is not a big challenge to Jatropha curcas. The seed of this plant consists of more than 30% oil which can be used for Bio-diesel production. It starts producing fruit after 4 or 5 years after establishment.
However, it is quite difficult to estimate the yield of the Jatropha Curcas that is able to grow in very different of conditions. Yield is a function of nutrients, water, sunlight and many more. For Jatropha Curcas, it seems that the intensity of rainfall is crucial in determining the yield. Generally, the yield is between 2 to 12.5 Metric Tons/hectare/year.
The graph below shows the yield of Jatropha Curcas with /without irrigation.
http://www.jatrophabiodiesel.org/jatrophaPlantation.php
http://www.jatrophabiodiesel.org/jatrophaPlantation.php
Below are the methods which can be used to extract Jatropha oil from seeds:
1. Oil Presses
2. Oil Expellers
3. Traditional Method
4. Hot Oil Extraction
5. Modern concepts
Oil content that has been extracted from the seeds is sending for further treatment which is also named as Jatropha Extraction Process. Jatropha Biodiesel uses the same principle as the First Generation Bio-fuel that is converting plant oil into biodiesel through Transesterification process.
The chart below shows more about the Jatropha Extraction Process.
Furthermore, the oil cake left after the extraction process is very rich in nutrients and is a very good bio-fertilizer for soil that is deficient in carbon and nutrients. We can produce electricity by burning the oil cake too!
In conclusion, Jatropha is a feedstock that can be used sustainably to produce Bio-diesel. This is because it has the performance characteristic comparable to fuel diesel can car can run on Jatropha oil without requiring much in modification in engines. The oil content is around 30% in the seeds and 50-60% in the kernel. This oil contains 21% saturated fatty acids and 79% unsaturated fatty acids. Jatropha oil brings hope to those developing countries which have a lot of degraded land. It can be used to prevent soil erosion too. By planting this Jatropha, not only the quality of land can be improved, the Bio-diesel produces can be either sold to other country or use in production of energy in own country. It increases rural incomes and alleviate poverty tribal communities and small farmers.
By substitute fuel diesel with Jatropha oil, it will bring us a lot of benefits such as:
ü Used as an alternative for diesel as a renewable source.
ü Have the properties that are similar to diesel fuel.
ü It is an oxygenated fuel and is also eco friendly.
ü Contains less sulphur.
ü Can be used in the diesel engine with little modification in the engines.
ü Emission of exhaust gas is reduced.
Can be used as Jet fuel and Light Hydrocarbon fuel
In addition, Jatropha is considered the cheapest among all the Bio-fuel. It has a price of $43 per gallon. The process of extracting oil from Jatropha is technologically simple and has high potential to be commercialised in years to come. Currently, India and Africa are the countries which produce the most Bio-diesel by using Jatropha. There is no doubt about the sustainability of Jatropha oil as you are planting a tree shrub that has a long lifespan and will continually does its job, producing oil and removing GHGs from the atmosphere.
Sustainability of Second Generation
In conclusion, Second Generation Biodiesel is generally a more sustainable source of fuel if compared to the first generation as it causes less impact to our food supply and environment. Besides that, its yield is relatively high when compared with yield of First Generation when using the same amount of land. Whole crop utilization method increases the yield and at the same time reduces the waste products from agricultural sectors as the wastes are being turned into Bio-Diesel as well! One of the distinct advantages of the Second Generation Bio-diesel is that the energy crops are able to grow on marginal land which helps to improve the condition of the land. However, undesirable conditions will have an effect on the yield of the crops. As such, living conditions of these energy crops need to be monitored so that the production of Bio-Diesel will be more economical. In addition, energy crops can be genetically engineered to increase the oil content in the plant which also increases the amount of fuel produced.
