Methodology

1. Analysis of Biofuels as Renewable Energy AlternativeVickie Sheree Durrah, RET Fellow 2009A.O. Sexton Elementary School RET Mentor: Dr. Andreas Linninger, PhDChicago Science Teacher Research (CSTR) NSF - RET Program Introduction Background Fossil fuels,the primary energy source for the U.S. and global economies, are consumed at astronomical rates, contributing to pollution, increased greenhouse gases and global warming. Annual population growth and increased industrialization has contributed to U.S. consumption, creating a demand for renewable energy sources to eliminate reliance on crude oil. Research as shown promise in burning lignocellulosic biomass, inedible organic plant material and wastes products to production of efficient and renewable energy by extracting energy, complex carbohydrates from lignin in the cell wall to produce green liquid transportation liquids - biofuels, ethanol, methanol, hydrogen and diesel. The processes required to produce these fuels involve a highly complex conversion of biomass to liquids (BTL) and gases to liquid (GTL). This evaluative tool serves to highlight the optional biomass processing pathways to produce biofuels: biomass saccharification, pyrolysis, gasification, Fischer Tropsch Synthesis (FT), and transesterification to determine the optimal technique for sustainable energy options. • Motivation • ~ 90 of our energy needs derived from fossil fuels • More than half of the crude oil we consume is imported • ~ 7 billion barrels crude oil consumed in U.S. annually = main producer of CO2 • Decreased supply, increased demand contributes to inflated prices for oil • Global depletion of fossils fuels at a faster rate than new ones are formed Objective • Analyze biomass as sustainable alternative in the production of “green” biofuels Methodology Biomass Saccharification: extraction of sugar from cell wall; specifically, lignin and cellulose and hemicellulose; ex: energy crops, corn, and sugar cane. • Lignocellulosic Biomass: any organic material derived from plants; lignin and complex carbohydrates, or cellulose found in the cell wall; includes energy and starch crops, wood based products and residuals, animal manures and algae. • 1.3 billion tons biomass available in trees and plants • 1 acre grasses & wood crops = ~ 5 dry tons biomass • Biomass Gasification (BTL): extraction of energy to convert biomass to synthesis gas CO, H, CH4 • Pyrolysis: combustion of biomass at high temperatures to produce syngas: • C + ½ CO2 CO • Water-Gas Shift Reaction: CO + H2O ↔ CO2 + H2 • Hydrolysis: breaking down complex sugars converting them into simple sugars • C6H12O11 + H20  C12H22O11 • (starch) (amylase) (maltose) • Fermentation: the conversion of the simple sugars to ethanol when bacteria feeds on sugarC6H12O6 2 C2H5OH + 2CO2 • (sugar) (alcohol) (carbon dioxide gas) • 1 acre corn = 183 bushels = 420 gallons bioethanol • Annual U.S. Capacity: 8.2 billion gallons bioethanol = 3.0 billion bushels corn • Transesterification: conversion of triglyceride oil from soybeans or vegetable oils, animal fats to free fatty alkyl esters - diesel and glycerin by reacting with methanol • Simplified Reaction • Triglycerides + Fatty Acids (<4%) + Alcohol  Alkyl esters + glycerin • 1 acre soybeans = 42.6 bushels = 60 gallons biodiesel • Annual U.S.Capacity: 450 million gallons = ~ 275 million bushels of soybeans • Fischer Tropsch Synthesis (GTL): conversion of syngas via biomass gasification to liquid hydrocarbons in production of hydrogen for fuel cell cars and electricity; involves carbon capture and sequestration; applied with gasification: CO + 2H2 - CH2 + H2O • Alcohol Synthesis • Syngas  hydrocarbons  methanol diesel/gasoline/jet fuels • CO2 + 2H2 CH3OH • Steam Methane Reforming  hydrogen (endothermic & exothermic) • CO shift conversion: CO + H2O ↔ CO2 + H2 • FT products includes hydrocracking of CH4 for H, parrafins, olefins • Capacity: 1 million dry tons biomass per year = 4400 barrels FT fuels Gasification & Fischer Tropsch Synthesis Conclusions Teaching Module Acknowledgements • NSF Grant EEC - 0743068 • Dr. Andreas Linninger, RET Director & Mentor UIC • Dr. Gerardo Ruiz, RET Program Manager- UIC • Sukhi Basati • Deepika Govind, REU Students will… • Communicate prior knowledge of crude oil and its role in the global energy crisis. • Distinguish renewable energy and nonrenewable energy. • Define sustainability. • Identify the basic techniques employed in production of biofuels. • Conduct a laboratory experiment testing a model fuel cell car. • Discuss the pros and cons of biofuels. • Biofuel processing pathways is costly and complex. • Energy intensive processing of biomass. • Biomass is optimal in production of all “green” transportation fuels. • Biomass gasification coupled with FT synthesis is currently the optimal technology for small scale clean production of “green” fuels.