2. CONTENTS What is bioethanol? Bioethanol Production Feedstocks Fuel Properties Application Advantages Disadvantages and Concerns Ethanol Controversy Comparison of Bioethanol and Biodiesel Case study [Brazil] Future development
8. Bioethanol Production (1) Concentrated Acid Hydrolysis ~77% of sulfuric acid is added to the dried biomass to a 10% moisture content. Acid to be added in the ratio of 1/25 acid :1 biomass under 50°C. Dilute the acid to ~30% with water and reheat the mixture at100°C for an hour. Gel will be produced and pressed to discharge the acid sugar mixture. Separate the acid & sugar mixture by using a chromatographic column .
9. Bioethanol Production (2) Enzymatic Hydrolysis (Not popular) (3) Dilute Acid Hydrolysis oldest, simplest yet efficient method hydrolyse the bio-mass to sucrose hemi-cellulose undergo hydrolysis with the addition of 7% of sulfuric acid under the temperature 190°C. to generate the more resistant cellulose portion, 4% of sulfuric acid is added at the temperature of 215°C
10. Bioethanol Production Wet milling process corn kernel is soaked in warm water proteins broken down starch present in the corn is released (thus, softening the kernel for the milling process) microorganisms, fibre and starch products are produced. In the distillation process, ethanol is produced.
11. Bioethanol Production Dry milling process Clean and break down the corn kernel into fine particles Sugar solution is produced when the powder mixture (corn germ/starch and fibre) is broken down into sucrose by dilute acid or enzymes. Yeast is added to ferment the cooled mixture into ethanol.
12. Bioethanol Production Sugar fermentation Hydrolysis process breaks down the biomass cellulosic portion into sugar solutions which will then be fermented into ethanol. Yeast is added and heated to the solution. Invertase acts as a catalyst and convert the sucrose sugars into glucose and fructose. (both C6H12O6).
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14. Feedstocks Sugar is required to produce ethanol by fermentation. Plant materials (grain, stems and leaves) are composed mainly of sugars almost any plants can serve as feedstock for ethanol manufacture Choice of raw material depends on several factors ease of processing of the various plants available prevailing conditions of climate landscape and soil composition sugar content
15. Feedstocks R&D activities on using lignocellulosic (woody materials) as feedstock Lignocellulosic biomass is more abundant and less expensive than food crops higher net energy balance accrue up to 90% in greenhouse gas savings, much higher than the first generation of biofuel However, more difficult to convert to sugars due to their relatively inaccessible molecular structure
16. Fuel Properties Energy content Bioethanol has much lower energy content than gasoline about two-third of the energy content of gasoline on a volume base
17. Fuel Properties Octane number Octane number of ethanol is higher than petrol hence ethanol has better antiknock characteristics increases the fuel efficiency of the engine oxygen content of ethanol also leads to a higher efficiency, which results in a cleaner combustion process at relatively low temperatures
18. Fuel Properties Reid vapour pressure (measure for the volatility of a fuel) Very low for ethanol, indicates a slow evaporation Adv: the concentration of evaporative emissions in the air remains relatively low, reduces the risk of explosions Disadv: low vapour pressure of ethanol -> Cold start difficulties engines using ethanol cannot be started at temp < 20ºC w/o aids
19. Application transport fuel to replace gasoline fuel for power generation by thermal combustion fuel for fuel cells by thermochemical reaction fuel in cogeneration systems feedstock in the chemicals industry
20. Application Blending of ethanol with a small proportion of a volatile fuel such as gasoline -> more cost effective Various mixture of bioethanol with gasoline or diesel fuels E5G to E26G (5-26% ethanol, 95-74% gasoline) E85G (85% ethanol, 15% gasoline) E15D (15% ethanol, 85% diesel) E95D (95% ethanol, 5% water, with ignition improver)
21. Advantages Exhaust gases of ethanol are much cleaner it burns more cleanly as a result of more complete combustion Greenhousegases reduce ethanol-blended fuels such as E85 (85% ethanol and 15% gasoline) reduce up to 37.1% of GHGs Positive energy balance, depending on the type of raw stock output of energy during the production is more than the input Any plant can be use for production of bioethanol it only has to contain sugar and starch Carbon neutral the CO2 released in the bioethanol production process is the same amount as the one the crops previously absorbed during photosynthesis
22. Advantages Decrease in ozone formation The emissions produced by burning ethanol are less reactive with sunlight than those produced by burning gasoline, which results in a lower potential for forming ozone Renewable energy resource result of conversion of the sun's energy into usable energy Photosynthesis -> feedstocks grow -> processed into ethanol Energy security esp. Countries that do not have access to crude oil resources grow crops for energy use and gain some economic freedom Reduces the amount of high-octane additives Fuel spills are more easily biodegraded or diluted to non toxic concentrations
23. Disadvantages and Concerns Biodiversity A large amount of arable land is required to grow crops, natural habitats would be destroyed Food vs. Fuel debate due to the lucrative prices of bioethanol some farmers may sacrifice food crops for biofuel production which will increase food prices around the world Carbon emissions (controversial) During production of bioethanol, huge amount of carbon dioxide is released Emission of GHGs from production of bioethanol is comparable to the emissions of internal-combustion engines
24. Disadvantages and Concerns Not as efficient as petroleum energy content of the petrol is much higher than bioethanol its energy content is 70% of that of petrol Engines made for working on Bioethanolcannot be used for petrol or diesel Due to high octane number of bioethanol, they can be burned in the engines with much higher compression ratio Used of phosphorous and nitrogen in the production negative effect on the environment Cold start difficulties pure ethanol is difficult to vaporise
25. Disadvantages and Concerns Transportation ethanol is hygroscopic, it absorbs water from the air and thus has high corrosion aggressiveness Can only be transported by auto transport or railroad Many older cars unequipped to handle even 10% ethanol Negatively affect electric fuel pumps by increasing internal wear and undesirable spark generation
27. Is it justifiable? ..to use agriculture land to grow energy crops instead of food crops when there are so many starving people in the world. In the developed countries that is not a problem, but in the developing ones where we have a large number of people living below the poverty this may lead to a crisis.
28. Ethanol Controversy Is burning biofuel more environmentally friendly than burning oil? Fact that producing biofuel is not a "green process“ requires tractors and fertilisers and land With the increase in biofuel production, more forests will be chopped down to make room for biofuel, ↑ CO2 Better alternative suggested by scientists.. steer away from biofuel and focus on reforestation and maximising the efficiency of fossil fuels instead
30. Case study [Brazil] Brazil the first to produce the cheapest ethanol in the world. WHY BRAZIL? Favourable conditions Tradition of culturing sugarcane Sugarcane being the most efficient raw materials for production of ethanol
31. Case study [Brazil] The FACTS Brazil second biggest producer of ethanol in the world (20 billion litres) Fuel used in 45 % of Brazilian vehicles is ethanol Feedstocks: sugarcane bagasse and straw (rich in cellulose and turning entire sugarcane biomass to be used with no wastage) 1 tonne of bagasse produce 186 litres of ethanol
32. Case study [Brazil] In 1930s Brazil’s ethanol industry started Government directed sugarcane into ethanol production Made addition of ethanol to gasoline compulsory In 1973 International oil crisis doubled Brazil’s expenditure on oil imports Government was forced to consider alternative sources of energy to decrease its dependency and spending on fossil fuels. In 1975 Increase ethanol production as a substitute for gasoline Invested in increasing agricultural production Modernising and expanding distilleries Establish new production plants Introduce subsidies to lower prices and reduce taxes for ethanol producers
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35. Case study [Brazil] SOLUTIONS: Vinasse was found to be a good fertiliser. Transportation system was developed Combination of trucks, pipes and ducts to carry Vinasse from the distilleries to the fields Bagasse was collected Produce energy, building on existing methods of burning the bagasse to power steam turbines for electricity generation Developed cauldrons under greater pressure More energy could be produced allowing ethanol plants to become more autonomous in terms of energy CONTRIBUTIONS IS TO KEEP ETHANOL PRODUCTION COSTS LOW
36. Case study [Brazil] Social impacts Created jobs for locals (mainly in rural areas) Brazilian sugarcane industry has a particularly poor record in respecting worker’s rights Expansion in sugar cane cultivation may increase food prices. This would leave the poor with a harder survival. Although the ethanol industry has greatly increased the wealth of the sugar and alcohol sector’s industries, the poor have to be the one handling the negative impacts.
37. Future development For bioethanol to become more sustainable to replace petrol, production process has to be more efficient Reducing cost of conversion Increasing yields Increase the diversity of crop used As microbes are use to convert glucose into sugar which is ferment in bioethanol Microbiology and biotechnology will be helpful in the genetic engineering
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