Lect No 1, 2, 3.pptx
- 1. Er. Piyush Ravindra kowe 8237869091 Assistant Professor of Agricultural Engineering SSWPCOA, Lakhni, Bhandara M.Tech (Farm Machinery & Power Engineering) B.Tech ( Agricultural Engineering)
- 2. Renewable energy refers to energy resources that occur naturally and repeatedly in the environmental and can be harnessed for human benefit. These energy resources are inexhaustible within the time horizonof humanity. Examples of renewable energy systems include solar, wind and geothermal energy (getting energy from the heat in the earth). We also get renewable energy from trees, plants, rivers and even from garbage. During recent years, due to the increase in fossil fuel prices and the environmental problems caused by the use of conventional fuels, we are reverting back to renewable energy sources such as solar, wind and hydraulic energies. Renewable energies are inexhaustible, clean and they can be used in a decentralized way (they can be used in the same placeas they are produced).
- 3. Stage Definition Energy source Primary energy Original source e.g. crude oil, coal not yet processed, natural uranium, solar, wind etc Final energy/secondary Energy in the form that reaches the end user, hot water or steam e.g., gas,fuel, oil, petrol, electricity Effective energy Energy in form used by the end user e.g., light, radiation heat, driving force orvehicles
- 4. A) Based on the usability of energy 1) Commercial sources of energy: The energy sources like petroleum products (diesel, petrol and kerosene oil) and electricity, which are capital intensive. Considering the fact that most of the commercial sources are also non- renewable and to some extent are imported to India, efforts are made to conserve such sources of energy. 2) Non-commercial sources of energy: Each and every energy source has some economic value. Some energy sources are available comparatively at low cost whereas others are capital intensive. The energy sources which are available cheaply are called non-commercial sources of energy whereas the ones which are capital intensive are called commercial energy sources. Ex. Human labour and bullocks. B) Based on traditional use 1) Conventional : those energy sources which have been traditional used for many decades Ex. fossil fuels, nuclear and hydro energy. 2) Non-conventional: Those energy sources which are considered for large scale use of oil crisis of 1973 are called non-conventional energy source. Ex. solar, wind, biomass etc.
- 5. C) Based on long term availability 1) Non renewable /Exhaustible: Those which are finite and do not get replenished after their consumption. Ex. Fossil fuels, nuclear, natural gas etc. 2) Renewable resources: Those which are renewed by nature again and again and their supply not affected by the rate of their consumption. Ex. Solar, Wind and Geothermal. D) Base on origin Fossil fuel Wind energy Solar energy Biomass energy Nuclear energy Solar energy Geothermal energy Tidal energy Hydro energy
- 6. Renewable Energy Source Technology / Application Solar Photovoltaic (PV) cells to produce electricity and Solar thermal system for heating water/air Wind Wind turbine to pump water, produce electricity or for any other mechanical use Water Hydro-electric, wave and tidal systems to produce electricity Biomass Direct combustion of gas produced from biomass, or biogas to generate electricity or heat - e.g. wood stoves or larger commercial operations Geothermal Using the temperature of the earth to produce
- 7. Features of comparision Renewable energy supplies Nonrenewable energy supplies Examples Wind, solar, biomass, tidal etc. Coal, oil, gas etc. Source Natural local environment Concentrated stock Normal state A current of energy Static store of energy Life time of supply Infinite Finite Cost at source Free Increasingly expensive Location for use Site and society specific General and international use Scale Small scale, economic, large scalemay present difficulties Increased scale often improvessupply costs, large scale frequently favored Skills Interdisciplinary and varied widerange of skills Strong links with electrical andmechanical engineering. Narrow range of skill Context Rural, decentralized industry Urban, centralized industry Dependence Self-sufficient system encouraged Systems dependent on outside inputs Pollution and environmental damage Usually little environmental harm, especially at moderate scale. HazardsWind, solar, biomass, tidal etc. from excessive wood burning, soil erosionfrom excessive biofuel use, largehydro reservoirs disruptive Environmental pollution common, and especially of airand water Deforestation and ecological sterilization from excessive air pollution Safety Local hazards possible in operation, usually safe when out of action May be shielded and enclosed to lessen great potential danger
- 8. Bio-diesel is a fuel, made from natural (biological) renewable resources which can be used directly in conventional diesel engines. Unlike fossil diesel, pure bio-diesel is biodegradable, non-toxic, essentially free of sulphur and aromatics and releases less emissions during combustion. Biofuels are transportation fuels like ethanol and biodiesel that are made from biomass materials. These fuels are usually blended with petroleum fuels namely with gasoline and diesel fuel, but they can also be used on their own. Biofuels has drawn significant attention due to increasing environmental concern and diminishing petroleum reserves. Bio-diesel fuel can be made from renewable vegetable oils, animal fats or recycled cooking oils by trans- esterification process. Biodiesel isthe fastest growing alternative fuel in the world. Ethanol is a alcohol fuel made from the sugars found in grains such as corn, sorghum, and wheat, as well as potato skins, rice, sugarcane, sugar beets and yard clippings by fermentation. Ethanol and biodiesel are also cleaner burning fuels,producing fewer air pollutants.
- 9. Biodiesel is commonly produced by the transesterification of thevegetable oil or animal fat feedstock. The process involves reacting vegetable oils or animal fats catalytically with a short-chain aliphatic alcohols (typically methanol or ethanol). There are several methods for carrying out this transesterification reaction including the a) common batch process b) supercritical processes c) ultrasonic methods d) microwave methods. A by-product of the transesterification process is the production of glycerol. For every 1 tonne of biodiesel that is manufactured, 100 kg ofglycerol are produced.
- 10. Preparation: care must be taken to monitor the amount of water and free fatty acids in the incoming biolipid (oil or fat). If the free fatty acid level or water level is too high it may cause problems with soap formation and the separation of the glycerin by-product. Catalyst is dissolved in the alcohol using a standard agitator or mixer. The alcohol/catalyst mix is then charged into a closed reaction vessel and the biolipid (vegetable or animal oil or fat) is added. The system from here on is totally closed to the atmosphere to prevent the loss ofalcohol. The reaction mix is kept just above the boiling point of the alcohol (around 70 属C) to speed up the reaction. Some systems recommend the reaction take place anywhere from room temperature to 55 属C for safety reasons. Recommended reaction time varies from 1 to 8 hours; under normal conditions the reaction rate will double with every 10 属C increase in reaction temperature. Excess alcohol is normally used to ensure total conversion of the fat or oil to its esters.
- 11. The glycerin phase is much denser than biodiesel phase and the two can be gravity separated with glycerin simply drawn off the bottom of the settling vessel. In some cases, a centrifuge is used to separate the two materials faster. Once the glycerin and biodiesel phases have been separated, the excess alcohol in each phase is removed with a flash evaporation process or by distillation. Care must be taken to ensure no water accumulates in the recovered alcohol stream. The by-product (i.e., glycerin) contains unused catalyst and soaps, that are neutralized with an acid and sent to storage as crude glycerin. Once separated from the glycerin, the biodiesel is sometimes purified by washing gently with warm water to remove residual catalyst or soaps, dried, and sent to storage.
- 12. It is a catalyst-free method and continuous process. In this method, transesterification process uses supercritical methanol at high temperatures and pressures. In the supercritical state, the oil and methanol are in a single phase and reaction occurs spontaneously and rapidly. The process can tolerate water in the feedstock. Also the catalyst removal step is eliminated. High temperatures and pressures are required, but energy costs of production are similar or less than catalytic production routes.
- 13. Ultra- and High Shear in-line or batch reactors allow production of biodiesel continuously, semi- continuously, and in batch-mode. This method drastically reduces production time and increases production volume. The reaction takes place in the high-energetic shear zone of the ultra- and high Shear mixer by reducing the droplet size of the immiscible liquids such as oil or fats and methanol. Therefore, the smaller the droplet size, the larger the surface area the faster the catalyst can react.
- 14. In the ultrasonic reactor method, the ultrasonic waves cause the reaction mixture to produce and collapse bubbles constantly. This cavitation provides simultaneously the mixing and heating required to carry out the transesterification process. The ultrasonic reactor method for biodiesel production drastically reduces the reaction time, reaction temperatures, and energy input. Industrial scale ultrasonic devices allow for the industrial scale processing of several thousand barrels per day.
- 15. Current research is being directed into using commercial microwave ovens to provide the heat needed in the transesterification process. The microwaves provide intense localized heating that may be higher than the recorded temperature of the reaction vessel. A continuous flow process producing 6 liters/minute at a 99% conversion rate has been developed and shown to consume only one-fourth of the energy required in the batch process. Although it is still in the lab-scale, development stage. The microwave method holds great potential to be an efficient and cost- competitive method for commercial-scale biodiesel production.
- 16. Bio-ethanol is an environmentally friendly fuel for vehicles. As a renewable source of energy, it reduces demand on fossil fuels while it burns more cleanly and with reduced emissions of CO2. As an energy source, bio-ethanol is carbon neutral so it reduces, by up to 70 %, the amount of greenhouse gas released into the atmosphere. The CO2 released during ethanol production and combustion in an engine has already been absorbed from the atmosphere during the growth of the crops due to photosynthesis. The reduction of greenhouse gases, to meet the climate change targets set by the Kyoto Protocol, is responsible for fueling the current boom in biofuels. Bio-ethanol is a versatile transportation fuel and fuel additive that offers excellent performance and reduced air pollution compared to conventional fuels.
- 17. 1.Feedstock preparation: Any plant material that contains carbohydrates. Common feedstocks include corn, sugarcane and wheat. The feedstock is cleaned and milled to create a fine powder that can be easily processed. 2.Pretreatment: Treat the feedstock with enzymes or chemicals to break down the complex carbohydrates into simple sugars. This makes it easier for microorganisms to convert the sugars into ethanol during the fermentation process. 3.Fermentation: Add yeast or other microorganisms to the feedstock. The microorganisms consume the sugars and produce ethanol as a byproduct. The fermentation process takes several days and must be carefully monitored to ensure optimal conditions for the microorganisms. 4.Distillation: After fermentation, the mixture of ethanol and water is heated to a high temperature, causing the ethanol to vaporize and separate from the water. This process is known as distillation. The resulting ethanol is then further purified using other techniques to increase its concentration and remove any impurities. 5.Dehydration: The final step is to remove any remaining water from the ethanol using molecular sieves or other techniques. This increases the concentration of ethanol and makes it suitable for use as a fuel. Once the bioethanol is produced, it can be used as a standalone fuel or blended with gasoline
- 19. Renewable and sustainable: Bioethanol is made from plant material, which is a renewable and sustainable resource. It can be produced using a variety of feedstocks, including corn, sugarcane, and cellulosic materials. Reduces greenhouse gas emissions: Bioethanol produces fewer greenhouse gas emissions than traditional fossil fuels, which can help to reduce the carbon footprint of transportation. Domestic production: Bioethanol can be produced domestically, which can help to reduce dependence on foreign oil. Better performance: Bioethanol has a higher octane rating than gasoline, which can improve engine performance and efficiency.
- 20. Lower energy density: Bioethanol has a lower energy density than gasoline, which means that it provides less energy per unit of volume. Corrosion: Bioethanol is more corrosive than gasoline, which can cause damage to engine components over time. Lower fuel efficiency: Due to its lower energy density, bioethanol typically has lower fuel efficiency than gasoline, which means that more fuel is required to travel the same distance. Availability: Bioethanol may not be widely available in all areas, which can limit its use as a fuel source.