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Patrick A. Topper Robert E. Graves Agricultural and Biological Engineering. BIOGAS 101: On-Farm Anaerobic Digestion (AD). This presentation is an introductory informational tool on biomass renewable energy with emphasis on Biogas.
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Patrick A. Topper Robert E. Graves Agricultural and Biological Engineering
BIOGAS 101:On-Farm Anaerobic Digestion (AD) This presentation is an introductory informational tool on biomass renewable energy with emphasis on Biogas. Comments on how this material can be made more useful for extension education are appreciated.
What’s Biogas? It’s a gaseousBiofuel made up of a mixture of methane (60%) and carbon dioxide (40%) – with trace amounts of hydrogen sulfide and water vapor (contaminants). • What Biogas is NOT … • Biogas is NOT pure methane (natural gas). • Biogas is NOT biodiesel. • Biogas is NOT bioethanol.
Compare Fuel BTU Values… GASES Biogas : Impure; expensive to compress and very expensive to liquefy; 600 BTU/ft3 or 80.2 BTU/gal. (vol.) @ atmospheric pressure Methane : Higher energy content than biogas (no CO2); expensive to compress and very expensive to liquefy; 1031 BTU/ ft3 or 137.8 BTU/gal. (vol.) @ atmospheric pressure Gaseous Propane (LP Gas) : 2570 BTU/ft3 or 343.6 BTU/gal. (vol.) @ atmospheric pressure LIQUIDS Liquefied Propane (LP Gas) : Concentrated, high energy liquid fuel 91,600 BTU/gal. Petroleum Gasoline : High energy, compact liquid fuel 124,000 BTU/gal. #1 Diesel Fuel : High energy, compact liquid fuel 136,000 BTU/gal.
= 1700 Gal. of Biogas 1 Gal. Liquid Petroleum THE BOTTOM LINE… Biogas is low in BTUs/gal. (vol.), so it isn’t feasible to use as a motor fuel. It needs to be used as a stationary fuel, such as in an electrical power-generating plant or boiler.
How Are Biofuels Produced? Anaerobic Digestion Biogas: • Manure • Microbes Fermentation and Distillation Bioethanol: • Yeast / Sugar • Alcohol Extraction, Blending, and Refining Biodiesel: • Refined Diesel Fuel • Refined Ag-Based Oils Distiller Ag- Based Oil(s) Biogas Liquid Refine / Blend Liquid Diesel Oil
Keep in Mind… • Biogas can be burned and used as a heat source (produce hot air, hot water or steam). • Biogas can be used to operate an engine generator set that produces electricity and if the waste heat is captured and used, (Combined Heat & Power-CHP), plant efficiency improves. • The monetary benefit occurs when the electricity generated is used to replace electricity that’s normally bought at retail. • A Combined Heat & Power (CHP) unit increases the cost of an anaerobic digester system. • You can store gas – but can’t store electricity. • PA Net Metering – power company must buy electricity generated, but you must meet their requirements.
Summary • Biofuels: Biogas, Bioethanol, Biodiesel • Use of Biogas: Heat or Electricity • AD Costs to Consider: Design, Materials, Temperature, Location, Permits, CHP Unit, Grid Interconnection, Extra Management and Knowledge • Feed Stocks: Manure and / or Food Waste • AD is for ODOR REDUCTION OF MANURE ! The energy is a bonus !
THANK YOU! With additional project support funding provided by: