INTRODUCTION Global warming is defined as temperature increase world wide due to green house gases emission and cause deletion to ozone layer . It mainly occurred due to the burning of fuel, Green house gases include chloro- fluorocarbon (CFC), carbon dioxide, nitrous dioxide, methane, sulphur dioxide. Carbon dioxide, sulphur dioxides are the major gases that cause global warming, co2 and so2 are mainly emitted from the burning of fossil fuel. Bio fuels are replaced for petroleum or fuels from fossils and they emit very low amount of sulphur dioxide and carbon dioxide . The bio-fuels are also used as the either partially or totally substitute in vehicle engines .
BACKGROUND Bio-fuels are the fuels obtain from plants (www.biomass.uk.com/glossary.php). And these fuels are gaseous, liquids or solids. Liquid bio fuels are categorised into bio diesel, bio alcohol and bio Ethanol.ethanol is bio-fuel, is mainly produced from corn while alcohol distillation. Ethanol is a produced more from sugar cane and maize as compare to the corn .
CRITICAL ANALYSIS OF CASE:
(Are bio-fuels a feasible option? By Jose' Goldemberg, Patricia Guardabassi) According to the case, Brazil is one of the highest producers of ethanol from sugarcane (Goldemberg, 2007).Ethanol is a good alternative for gasoline (Moreira and Goldemberg, 1999),ethanol produced in brazil from a sugar cane can be used as a substitute for gasoline(Mathews, 2007), If ethanol is from agricultural product it does not contain any impurities like sulphur dioxide which commonly found in fossil fuels and proper practices of agriculture reduce green house gases(Goldemberg, 2007), united state states producing ethanol from maize leads to deforestation (Laurence (2007) ),reduction of greenhouse gases cannot reduced only by decreasing but also decreased by environmental indicator factor like deforestation and reducing ash (Searchinger et al. (2008)).when compare with gasoline produced from maize and sugarcane ,maize emits 18%less CO2 where as from sugarcane reduce about 91%less CO2(Goldemberg, 2007).the world 6%of land is used for cultivating crops, so bio-fuels results price of crops increased(FAO, 2007).but not all bio-fuels have same impact on prices of food ,the ethanol produced from sugar in brazil have no impact on sugar prices (Goldemberg, 2007).The larger amount of ethanol is exported from southern hemisphere countries like brazil, which has good agricultural resources like land and climatic conditions suitable for sugar cane used for ethanol production(Mathews, 2007),so production from sugarcane decrease deforestation( Searchinger et al. (2008)). The use of bio-fuels decreases pollution, deforestation and also no effect on the price of crops.
Case study about Biodiesel from microalgae According to the articles biodiesel is also produced micro algae .Micro algae are driven from sunlight cell that is used for the production bio-fuels, foods by utilization of carbon dioxide (Walter et al., 2005), it produces different types of renewable fuels. micro algae can be obtained from hydro carbons, lipids (Banerjee et al., 2002; Metzger and Largeau, 2005; Guschina and Harwood, 2006), Methane is produced from algal biomass by algal digestion (Spolaore et al 2005).biodiesel from liquid algal biomass (Gavrilescuand Chisti, 2005) algal biomass can be produced majorly by two process raceway pond and photo synthesis bio reactor; the raceway ponds is 0.3m diameter circular pounds having pure water is used for biomass production and in photosynthetic bioreactor production consist of an array of glass or transparent plastic tubes and photo bioreactor is used for capture of sunlight and it produce more biomass as compare to the race pound in a hectare. The us government is sponsoring for the study of biomass production of race way pond (Sheehan et al., 1998), fuels produced from the algae government kept regulations such as ASTM bio diesel standard6751(Knothe, 2006) and EU have certain standards for biodiesel used for transportation such as STANDARD EN 14214 and STANDARD EN 14213(Knothe, 2006).the cost of production by photosynthetic bio reachtor is cheap compare to race way pound and the cost of biomass per kg is $2.9 to$3.5(Humphreys, 1991; Molina,Grima et al., 2003). So production cost can be decreased by using genetically modified and photo engineering technologies, so production of biodiesel from micro algae can be used as alternative for fossil fuels.
Comparison; Both the cases are related to production of biofuel in terms of economical and environmental factors, In the case about ethanol from and biodiesel from algae are used for the substitute for the fossil fuels. Majorly Brazil is using sugar cane for the ethanol production (Goldemberg, 2007)where as now US is developing technology for the production biodiesel from biomass(Sheehan et al., 1998).Ethanol and biodiesel reduce sulphur dioxide .ethanol from sugar cane decrease deforestation and in the case of bio diesel from algae produced from waste water treatment such as photosynthetic bioreactor and race way ponds, brazil have favorable climate for the production of sugar and for the algae is suite for all types of climates and mainly from waste water but it is in experimental level and no company producing from algae, Ethanol produced from the sugar cane decrease 91%of co2(Goldemberg, 2007), But biodiesel production from biomass by use of co 2 which is produced by power plants using fossil fuels(Sawayama et al., 1995; Yun et al., 1997). Ethanol production leading to the deforestation but in the case of biomass production only by sunlight and water, ethanol produced from sugar cane economically efficient but in case of production of biodiesel it is very costlier. Bio fuel from crops has negative effect like food prices. Ethanol produced from sugar is used as gasoline and methane is produced from biomass .ethanol can be produced by
Conclusion There are many benefits for the environment, economy and consumers in using bio-fuels. Bio-oil can be used as a substitute for fossil fuels to generate heat, power and/or chemicals. Bio-fuels are made from biomass through thermochemical processes such as pyrolysis, gasification, liquefaction and supercritical fluid extraction or biochemical processes. Biochemical conversion of biomass is completed through alcoholic fermentation to produce liquid fuels and anaerobic digestion or fermentation to produce biogas. In wood derived pyrolysis oil, specific oxygenated compounds are present in relatively large amounts. Basically, the recovery of pure compounds from the complex bio-oil is technically feasible but probably economically unattractive because of the high costs for recovery of the chemical and its low concentration in the oil. Ethanol, bio-diesel and bio-gas are the most useful fuels from agricultural sources. Ethanol demand is expected to more than double in the next ten years. For the supply to be available to meet this demand, new technologies must be moved from the laboratories to commercial reality. The world ethanol production is about 60% by feedstock from sugar crops. Most of the bio-diesel that is currently made uses soybean oil, methanol and an alkaline catalyst. The high value of soybean oil as a food product makes production of a cost effective fuel very challenging. However, there are large amounts of low cost oils and fats such as restaurant waste and animal fats that could be converted to bio-diesel.