Sunlight Ancient and Modern: the Relative Energy Efficiency of Hydrogen from Coal and Current Biomass

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Please use this identifier to cite or link to this item: http://hdl.handle.net/1853/4786

Title: Sunlight Ancient and Modern: the Relative Energy Efficiency of Hydrogen from Coal and Current Biomass
Author: Zhang, Ling
Abstract: The significance of hydrogen production is increasing as fossil fuels are being depleted and energy security is of increasing importance to the United States. Furthermore, its production offers the potential to alleviate concerns regarding global warming and air pollution. In this thesis we focused on examining the efficiency of hydrogen production from current biomass compared to that from fossil fuel coal. We explored the efficiencies of maximum hydrogen production from biomass and from coal under current technology, namely coal gasification and biomass pyrolysis, together with following-up technologies such as steam reforming (SR). Bio-oil, product from pyrolysis and precursor for steam reforming, is hard to define. We proposed a simulation tool to estimate the pyrolytic bio-oil composition from various biomasses. The results helped us understand the accuracy that is needed for bio-oil composition prediction in the case it is converted to hydrogen. Hydrogen production is energy intensive. Therefore, heat integration is necessary to raise the overall thermodynamic efficiencies for both coal gasification and biomass pyrolysis. The results showed that considering the ultimate energy source, sunlight, about 6-fold more sunlight would be required for the coal to hydrogen than that for biomass to hydrogen. The main difference is in the efficiency of conversion of the ancient biomass to coal and therefore, for modern mankind, this loss has already been incurred.
Type: Thesis
URI: http://hdl.handle.net/1853/4786
Date: 2004-08-23
Publisher: Georgia Institute of Technology
Subject: Biomass
Coal
Pyrolysis
Gasification
Steam reformation
Hydrogen production
Sunlight
Heat integration
Pyrolysis
Biomass energy
Coal gasification
Hydrogen as fuel
Department: Chemical Engineering
Advisor: Committee Chair: Realff, Matthew; Committee Member: Jones, Christopher; Committee Member: Teja, Amyn; Committee Member: White, David
Degree: M.S.

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