Biochemical and Thermochemical Conversion of Biomass.pptx

Unit1 - BIOMASS CHARACTERIZATION

1. KONGUNADU COLLEGE OF ENGINEERING AND TECHNOLOGY (Autonomous) Department of Agricultural Engineering Course: Biochemical and Thermo chemical Conversion of Biomass Topic : Biomass Characterization By Mr. M.Prabhu , Assistant Professor, Department of Agricultural Engineering, Kongunadu College of Engineering and Technology

2. Unit – 1 Biomass Characterization Biomass Biomass is defined as the organic matter derived from biological materials such as plants, animals, microorganisms and municipal wastes. It is a renewable form of energy as it can be replenished within a short period. It can be used as a solid fuel, or converted into liquid or gaseous forms for the production of electric power, heat, chemicals or fuels. Reasons for utilizing biomass Readily available and renewable Non-fossil forms of fixed carbon are not depletable . Biomass is available in large quantities. Combining waste disposal and energy recovery processes offers recycling opportunities as well as improved disposal technology, often at low cost. Clean and nearly pollution free combustion. Energy and capital requirement for production is low

3. Biomass conversion chart

4. TYPES OF BIOMASS Agricultural Residues These are the Biomass sources or materials that are left in an agricultural field or orchard after the cro harvesting. The residues include stubble like leaves, stems, stalks, and seed pods. Animal Waste Animal wastes are generally the excreted materials from living animals and can also include hay, straw, organic debris and wood shavings. Forestry Residues It is the residue which is left over from logging operations that may include branches, tree tops, sawdust and stumps. Wood Wastes It is the portion of the waste stream which comprises discarded wood products, stumps, whole trees or pruned branches obtained during park or street maintenance. Industrial Wastes It is defined as the waste which is generated by manufacturing or industrial processes. It includes a variety of waste including dirt, gravel, cafeteria garbage, concrete and masonry, scrap metals, oil solvents, trash, chemicals, wood, weed grass, trees, etc.

5. Municipal Solid Wastes and Sewage Also known as trash or garbage, it is the everyday items that we use and throw away such as grass clippings, furniture, clothing, newspapers, appliances, paint, batteries, product packaging, kitchen waste, etc. FUELS FROM BIOMASS The technologies to treat biomass for conversion into fuel First Generation (1G) Biofuels : First generation biofuels are the biofuels made from sugar, starch, vegetable oil, or animal fats using conventional or established technology. The primary feedstock for the production of first generation biofuels are often sugarcane juice or molasses, grains starch is fermented into bioethanol , or sunflower seeds, which are pressed to produce an oil that can be converted to biodiesel through a chemical process. Biodiesel is commonly produced through a process called transesterification which enable transformation of triglycerides (fats and oils) into biodiesel and glycerin.

6. Second Generation (2G) Biofuels

7. The second generation biofuels are produced from the non-food crops, including lignocellulosic biomass, especially crop-residue or waste biomass in the form of stalks and straw of wheat, rice, corn, and other biomass residues. Biomass feedstock can be converted into different fuels using a range of processes to generate cost-effective biofuels production such as biomethanol , Bio-DME, Fischer- tropsch diesel, biodiesel, mixed alcohols, bio-oil and biohydrogen , syngas , biogas, etc. Third Generation (3G) Biofuels The third generation biofuels are biofuels produced from algae. Algal biomass is a feedstock to reckon with, as they have potential to produce biodiesel, bioethanol , biogas, biohydrogen , etc. Production of biofuel processes or transformation of algal biomass into biodiesel through transesterification or conversion of algal biomass into bioethanol and biohydrogen (fermentation), biogas (anaerobic digestion), biooil ( pyrolysis ) and syngas (gasification)

8. Fourth Generation (4G) Biofuels Fourth generation biofuels are merely a step further from the third generation biofuels . It is mostly based on metabolic engineering, a powerful tool to improve biofuel production, either through genetic modification to increase CO2 capture and lipid production as well as to develop low-input, fastgrowing energy crops with reduced fertilizers, insecticides, and water requirements or targeted alteration of metabolic pathways into a model organism toward better biofuel yields. TERMS AND UNITS USED IN BIOMASS PRODUCTION Bagasse , Biomass, Biomass energy (or “ biopower ”) , Carbon dioxide (CO2) , Carbon monoxide (CO), Carbon neutral, Chips , Closed loop , Co-firing, Co-generation, Combustion, Combustion air, Corn stover , Dry ton, Energy Crop, Feedstock, Fixed bed, Fixed carbon , Fluidized bed, Fly ash, Forestry residues, Fossil fuel, Gasification, Gas turbine, Greenhouse gas, Grid, Herbaceous plants, Herbaceous energy crops, Hydrocarbon, Landfill gas, Methane (CH4), Moisture, Sales generating plants, Scrubber, Self-generating plants, Wet scrubber,

9. BIOMASS FUEL CHARACTERIZATION The characterization of the conversion processes of lignocellulosic biomass to biofuels . Typical biomass components Cellulose A polysaccharide in which D-glucose is linked uniformly by β- glucosidic bonds. Its molecular formula is (C6H12O6)n. The degree of polymerization, indicated by n, is broad, ranging from several thousand to several tens of thousands. Hemicellulose A polysaccharide whose units are 5-carbon monosaccharides including D- xylose and Darabinose , and 6-carbon monosaccharides including D-mannose, D- galactose , and Dglucose . The 5- carbon monosaccharides outnumber the 6-carbon monosaccharides , and the average molecular formula is (C5H8O4)n Lignin Starch Like cellulose, starch is a polysaccharide whose constituent units are D-glucose, but they are linked by α- glycosidic bonds. Proteins Other components (organic and inorganic ) Total Solids Ash Determination Structural Carbohydrates Acetyl Content Ethanol Content

10. Properties of biofuels Moisture Energy Content Mass, Volume and Density Density Particle density Bulk density Itis defined as ratio of dry material to bulk volume and is relevant for the volume needed for transportation and storage. Total ash and ash melting temperature Shape and particle size Conversion factors

11. Supply chain Introduction Bioenergy plays a key role in mitigating climate change, contributing more to the primary energy supply than any other renewable energy source. HARVESTING & COLLECTION The biomass harvesting and collection process varies greatly depending on type of feedstock, local conditions and final usage. These processes include advanced systems for collection and harvesting of timber and forest residues. Biomass from Forest Different sources and purposes of usage of the original feedstock affect how it is collected and enters the supply chain of feedstock-to-energy. Harvesting residues In slash harvesting, foilage and small branches are collected to be used as biomass fuel, residues that are otherwise often left on site after timber harvesting.

12. Tree felling systems In cut-to-length systems trees are felled and processed directly in the forest. They are generally cut to 2- 4-meter-long logs, with branches and tops removed directly after felling. These residues are left in the forest, either spread out in the harvested area or collected in rough piles. The collection of slash for energy purposes is hence a separate step in the process, with additional costs. Medium to small scale The wood is harvested and collected usually as firewood for their own use in wood boilers/wood stoves or for sale. These forests are sustainably managed where harvesting is done usually by a mechanized handheld saw. Agricultural crop residues In comparison to biomass from forests, harvesting of agricultural residues is often done in easily accessible areas and integrated with harvesting processes for conventional agricultural products, which in many cases are highly mechanized.

13. Balers A common method for collection of agricultural residues is in the form of bales. If the main product of the harvest is grain, this is harvested first, leaving the rest of the plant on the field. These are thereafter collected in rows by a machine called windrower. Thereafter, the residues are formed into bales with a machine called baler. Forage harvesters Another alternative for harvesting of whole plants is using forage harvesters. With this technology, standing plants are collected and loaded directly on trucks. Mobile Pelletizers Mobile pellet plants that are carried around on the field by tractors or trucks and can be loaded with bales, reducing cost by not having to move the bales to the pellet plant.

14. PRETREATMENT & UPGRADING Drying Moisture content Drying process Densifying STORAGE & HANDLING In most cases, biomass and biofuels have to be stored, between different stages of the supply chain and during shorter or longer periods before being used for heat or power generation. In some regions, the demand for heat and electricity varies greatly between seasons. Storage size The size of the storage is important to optimize. A larger storage unit is often preferred since it allows purchasing larger quantities at one occasion, resulting in a lower unit price. Ventilation Another important aspect when considering dry biomass is ensuring sufficient ventilation, in order to avoid condensation and prevent mold, of which spores can be a serious health hazard if inhaled, as well as to allow additional drying and minimize decomposition of biomass.

15. Drainage Drainage furthermore has to be incorporated in case water somehow gets into the storage area, and so that the area can be cleaned if necessary. Wet biomass Wet biomass such as animal slurries and liquid biofuels are stored in tanks, and can be pumped in pipelines in the same way as traditional liquid fossil fuels. TRANSPORTATION & HANDLING Biomass feedstock is often harvested from a relatively large area, not always in close proximity to a power plant or upgrading facility. There are many different options for transporting biomass and biofuel , and the most appropriate mode of transportation depends on the type, stage in the supply chain, distance of transportation as well as geographic and infrastructure conditions. Tipper trailer or truck Flatbed trailer Tanker, grain or animal feed vehicle Timber haulage wagon Container and container lorry Walking floor trailer – for transport of wood chips.

16. Chipper-truck Rail Inland waterway Ship Briquettes Briquetting is the process of densification of biomass to produce homogeneous, uniformly sized solid pieces of high bulk density which can be conveniently used as a fuel. In this process, the raw material is pressed together at an elevated temperature and forced through an orifice. Advantages of briquettes Better feed handling characteristics Higher calorific value Improved combustion characteristics Reduced particulate emissions More uniform size

17. Binder less technologies The compaction of loose biomass without any binding material is done using the technologies Die and punch technology The piston presses are also known as ram and die technology. In this case the biomass is punched into a die by a reciprocating ram with a very high pressure thereby compressing the mass to obtain a briquette. The briquette produced is 60 mm in external diameter. This machine has a 700 kg/hr capacity and the power requirement is 25 kW. The ram moves approximately 270 times per minute in this process. The merits and demerits of piston press briquetting machine are There is less relative motion between the ram and the biomass hence, the wear of the ram is considerably reduced. It is the most cost-effective technology currently offered by the Indian market. Some operational experience has now been gained using different types of biomass. The moisture content of the raw material should be less than 12% for the best results. The quality of the briquettes goes down with an increase in production for the same power. Carbonisation of the outer layer is not possible. Briquettes are somewhat brittle.

18. Screw technology In this process, the biomass is extruded continuously by one or more screws through a taper die which is heated externally to reduce the friction. The outer surface of the briquettes obtained through this process is carbonized and has a hole in the centre which promotes better combustion. Standard size of the briquette is 60 mm diameter. The main merits and demerits of this technology are : The output from the machine is continuous and not in strokes, and is also uniform in size. The bulk density is higher The outer surface of the briquette is carbonized facilitating easy ignition and combustion and also provides an impervious layer for protection against moisture ingress. The central core of the briquette is hollow which provides a passage for supplying the air necessary for combustion. The machine runs very smoothly with no shock loads. The machine is very light due to the absence of reciprocating parts and flywheel. The power consumed by this equipment is very high. The wear rate of the screw is very high. There is a limitation on the raw material that can be compacted.

19. Types of screw presses Conical screw press

20. Screw press with heated die

21. Twin screw press.

22. Hydraulic press based technology

23. Roller Press

24. Pelletization The biomass pelletization process consists of multiple steps including raw material pre-treatment, pelletization and post-treatment

25. Feedstock storage An effective feedstock storage system is necessary so as to keep biomass away from impurities and offer adequate protection from rain and moisture Removal of undesirable impurities Raw material should be filtered before grinding to remove materials such as stones or metal fragments. Size reduction The raw material must be reduced to a uniform size that is adequate for the pellet mill. The milled material going into the pellet mill has to be smaller than the die holes to prevent blocking of the holes. Material transportation Once reduction has taken place, the material must be moved on to the next process. Screw conveyors are the most commonly used systems for transporting the material through the pelletization process because of the low cost involved. Biomass drying In pelletization techniques, the moisture percentage of the raw material should be between 10% and 20% to assure high-quality pellet production. However, the exact percentage to produce quality pellets is specific to each raw material.

26. Mixing and conditioning Not all raw materials require mixing. Nevertheless, if necessary, mixers are used after the raw material has been milled and dried to: when the raw material presents significant changes in moisture percentage, binding properties or material density. Pellet production Pellets are finally made by pellet mills, also known as pellet presses or extruders, which are available in a range of sizes. Generally, every 100 horsepower provides a capacity of approximately 1 ton of pellets per hour. Types of pellet mills Flat die pellet mills,which are used for small- to medium-scale pelletindustries . Round die pellet mills, which are applied to medium- and large-scale pellet industries. Flat die mills use a flat die with slots.

27. The powder is introduced into the top of the die and, as the die rotates, a roller presses the powder through the holes in the die. A cutter on the other side of the die cuts the exposed pellet free. Round die pellet mills In the round/ring die, there are radial slots throughout the die. The die is positioned vertically, powder is fed into the centre of the die and spreaders evenly distribute the powder. Two or more rollers then compress the powder through the die holes.