Transcript Document
Rosalie Forest Eco Lodge ECOFEST 2009 Introduction to Biogas, May 4th, 2009 Presented by Vincent Martineau Jessica Worley Who We Are Vincent Martineau, B.Eng Bioresource Focused on sustainable technologies, water management and land development. Jessica Worley, B.Eng Civil and Applied Mechanics Specialty in geoenvironmental engineering and water resource management. Design and Construction of a Biodigester NativeSun NRG & Bellairs Research Institute Obtained biogas experience in Barbados during the Fall of 2007 Overview •Goals & Objectives •Anaerobic Digestion •Biodigesters •Biogas •Design Specifications •Recommendations Source: www.knowledgepublications.com Source: www.knowledgepublications.com Goal Design and construction of a biodigester to produce biogas Objectives • Create a source of fuel for cooking; • Provide a fertilizer from the digested waste; and • Improve health conditions by isolating wastes in a sealed container to reduce airborne pathogens from raw manure. What is a Biodigester? • A device that mimics the natural decay process of organic matter • Biogas is produced from anaerobic decay (decay that occurs without oxygen) Anaerobic Digestion in a Biodigester • Digester is fed a mixture of water and waste called a slurry • Daily, fresh slurry is added, displacing previous days load that bacteria have started to digest • First, digestible organic matter is broken down by acid-producing bacteria • By-products are then broken down by methaneproducing bacteria (journeytoforever.org/biofuel_library/) Biogas: Green Energy • 50-70% methane; • 30-40% carbon dioxide; • Insignificant amounts of oxygen and hydrogen sulfide (H2S). • Biogas burns without soot or ash being produced • Methane is a combustible gas • Biogas will be used to generate energy for the cooking needs here at Rosalie Forest Eco Lodge (plascoenergygroup) History of Biogas • One of the oldest forms of renewable energy • Marco Polo mentioned the use of the technology. Probably goes back 2000-3000 years ago in ancient Chinese literature • The earliest evidence of use in Assyria (10th century BC) History of Biogas • Jan Baptita Van Helmont determined in 1630 that flammable gases could evolve from decaying organic matter. • Anaerobic digestion first described by Benjamin Franklin 1764. • Count Alessandro Volta in 1776 found a correlation between amount of decaying organic matter and amount of flammable gas produced. • In 1808, Sir Humphrey Davy determined that methane was present in the decay process. History of Biogas Cont’d • First digestion plant was built in 1859 in Bombay, India for a leper colony • Exeter, England, in 1895: biogas used to power street lamps • 1920’s and 30’s interest in anaerobic digestion increased • Interest in Biogas has been cyclical Examples of Digesters Around the World Costa Rica Digesters Around the World (cont’d) India (ARTI) Digesters Around the World (cont’d) United States Princeton, Minnesota Digesters Around the World (cont’d) KVIC Digester (used in India and China) Work log of what we did Prototype Design Advantages Reduction in scum accumulation Temperature Control Ease of operation Durable Small footprint Low cost What Type of Waste Produces Biogas? • Any organic waste can produce biogas • Human, manure, fruit and vegetable waste What Type of Waste Does NOT Produces Biogas? • Fiber rich waste such as wood, leaves, etc. are difficult to digest • Heavy metals • Inorganic materials in high concentration (Nitrate, Sodium, Sulphate, Sodium, Potassium, Calcium, Magnesium, etc) How Much Biogas Can I Get From My Waste? • Amount of biogas depends on the waste itself and design of the digester. • Some digesters can yield 20 liters of biogas per kilogram of waste up to 800 liters per kilogram. • Factors: waste quality, digester design, temperature, system operation, presence of oxygen. How Much Energy is in Biogas? • Average fuel value of methane = 1000 BTU/ft3 • Average fuel value of propane = 2500 BTU/ft3 • 1 BTU/ft3 = 37.2589 KJ/m3 How Much Energy is in Biogas? • Therefore, using the SI system, Fuel Value units: • FV methane = 1000 * 37.2589 KJ/m3 = 37258.9 KJ/m3 • FV propane = 2500 * 37.2589 KJ/m3 = 93147.3 KJ/m3 • FV propane / FV methane = 2.5 • When both fuels are burned completely, propane produces 2.5 times more energy per unit of volume. How Much Biogas Do I Need? • For Example: We want 40 lbs of propane-equivalent per week. • Biogas is 50-70% methane, 30-50% CO2 and 5-15% N2, H2, etc. • 40 lbs propane * 2.5 = 100 lbs of methane • 100 lbs of methane / 60% = 166.67 lbs of biogas Specifications • Input: 1 kg of donkey manure, 1 kg of food waste and 15 liters of water • Volume of tank: 55 US gal (~208.2 litres, ~0.208 cubic meter) Assuming: • Total Solids (TS) ~15% • Volatile Solids (VS) ~70% • Hydraulic Retention Time: 10 days How to calculate Organic Loading Rate (OLR) • OLR = kg VS added / day / m3 reactor • OLR = Manure * TS% * VS% / Volume • Organic Loading Rate: 2.02 kg VS added / day / m3 reactor How much money did we just save? • Methane production estimated at XXX m3/day (equivalent to XXX kg of propane/day) • Economic gain of about XXX $/year if fully used • Low Cost of construction: ~250 $EC Obstacles Problem Solving • Economic: Keeping it inexpensive • Recycled materials • Time • Equipment: Limited • Weather: When it rains, it pours! • Have friends around • Borrow and buy • Work in-between the showers! Implementation Plan Research of existing technology and systems Inventory of resources Budget Design Construction Testing Cook! Resources www.journeytoforever.org www.anaerobic-digestion.com/index.php www.biogas.psu.edu www.arti-india.org/content/view/12/28 www.ruralcostarica.com/biogas.html http://www.fao.org/docrep/t0541e/T0541E00.htm#Contents Thank You! Questions?