Sugarcane ethanol: Contributions to climate change - BAFF

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Chapter 7 maximised fuel production, with little or no electricity co-production, generally performs economically somewhat better than once-through concepts. Hot (dry) gas cleaning generally improves the total e�ciency, but the economical e�ects are ambivalent, since the investments also increase. Similarly, CO 2 removal does increase the total e�ciency (and in the FT reaction also the selectivity), but due to the accompanying increase in investment costs this does not decrease the product costs. �e bulk of the capital investment is in the gasi�cation and oxygen production system, syngas processing and power generation units. �ese parts of the investment especially pro�t from cost reductions at larger scales. Also, combinations with enriched air gasi�cation (eliminating the expensive oxygen production assumed for some methanol and hydrogen concepts) may reduce costs further. Several technologies considered here are not yet fully proven or commercially available. Pressurised (oxygen) gasi�ers still need further development. At present, only a few pressurised gasi�ers, operating at relatively small scale, have proved to be reliable. Consequently, the reliability of cost data for large-scale gasi�ers is uncertain. A very critical step in all thermal systems is gas cleaning. It still has to be proven whether the (hot) gas cleaning section is able to meet the strict cleaning requirements for reforming, shi� and synthesis. Liquid phase reactors (methanol and FT) are likely to have better economies of scale. �e development of ceramic membrane technology is crucial to reach the projected hydrogen cost level. For FT diesel production, high CO conversion, either once through or a�er recycle of unconverted gas, and high C5+ selectivity are important for high overall energy e�ciencies. Several units may be realised with higher e�ciencies than considered in this paper: new catalysts and carrier liquids could improve liquid phase methanol single pass e�ciency. At larger scales, conversion and power systems (especially the combined cycle) have higher e�ciencies, further stressing the importance of achieving economies of scale for such concepts. 3.2. Production of ethanol from sugarcane Ethanol production from sugarcane has established a strong position in Brazil and increasingly in other countries in tropical regions (such as India, China and various countries in Sub- Saharan Africa). Production costs of ethanol in Brazil have steadily declined over the past few decades and have reached a point where ethanol is competitive with production costs of gasoline (Wall-Bake et al., 2008). As a result, bioethanol is no longer �nancially supported in Brazil and competes openly with gasoline. Large scale production facilities, better use of bagasse and trash residues from sugarcane production e.g. with advanced (gasi�cation based) power generation or hydrolysis techniques (see below) and further improvements in cropping systems, o�er further perspectives for sugarcane based ethanol production. 166 Sugarcane ethanol
Biofuel conversion technologies Improvement options for sugarcane based ethanol production are plentiful (Damen, 2001; Groen, 1999). It is expected that the historic cost decreases and productivity increments will continue. An analysis of historic and potential future improvements in economic performance of ethanol production in Brazil (Wall Bake et al., 2008) concludes that if improvements in sugarcane yield, logistics (e.g. green can harvesting techniques and utilisation of sugarcane trash), overall e�ciency improvement in the sugar mills and ethanol production (e.g. by full electri�cation and advanced distillation technology) as well as the use of hydrolysis technology for conversion of bagasse and trash to ethanol, ethanol yields per hectare of land may even be tripled compared to current average production. �e key limitations for sugarcane production are climatic and the required availability of good quality soils with su�cient and the right rainfall patterns. 3.3. Ethanol from (ligno)-cellulosic biomass Hydrolysis of cellulosic (e.g. straw) and lignocellulosic (woody) biomass can open the way towards low cost and e�cient production of ethanol from these abundant types of biomass. �e conversion is more di�cult than for sugar and starch because from lignocellulosic materials, �rst sugars need to be produced via hydrolysis. Lignocellulosic biomass requires pretreatment by mechanical and physical actions (e.g. steam) to clean and size the biomass, and destroy its cell structure to make it more accessible to further chemical or biological treatment. Also, the lignin part of the biomass is removed, and the hemicellulose is hydrolysed (sacchari�ed) to monomeric and oligomeric sugars. �e cellulose can then be hydrolysed to glucose. Also C5 sugars are formed, which require di�erent yeasts to be converted to ethanol. �e sugars are fermented to ethanol, which is to be puri�ed and dehydrated. Two pathways are possible towards future processes: a continuing consolidation of hydrolysis-fermentation reactions in fewer reactor vessels and with fewer micro organisms, or an optimisation of separate reactions. As only the cellulose and hemicellulose can be used in the process, the lignin is used for power production (Figure 4). Biomass Chipping Hemicellulose hydrolysis Enzyme growth Cellulose hydrolysis Fermentation Gas turbine or boiler Steam turbine Distillation Ethanol Electricity Figure 4. Generic process scheme for the production of ethanol from lignocellulosic biomass. Sugarcane ethanol 167
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Sugarcane ethanol Contributions to
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Table of contents Foreword 11 José
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Chapter 8 �e global impacts of US
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Foreword �e use of biofuels as a
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Executive summary Do biofuels help
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Executive summary 12. Projections o
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Chapter 1 Introduction to sugarcane
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Introduction to sugarcane ethanol A
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Introduction to sugarcane ethanol C
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Introduction to sugarcane ethanol F
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Introduction to sugarcane ethanol H
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Chapter 2 Production (million tons)
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Chapter 2 Table 2. Sugarcane produc
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Chapter 2 Harvested area (million h
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Chapter 2 million hectares 8 7 6 5
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Chapter 2 Table 5. Global significa
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Chapter 2 (FAOSTAT, 2008). �e lan
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Chapter 2 indicating that sugarcane
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Chapter 2 and vinasse produced duri
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Chapter 2 • • • • Harvested
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Chapter 2 2.2. AEZ assessment of la
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Chapter 2 The quantified descriptio
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Chapter 2 Table 8 summarizes by reg
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Chapter 2 Table 9. Suitability of u
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Chapter 2 Table 10. Suitability of
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Chapter 2 of bio-diversity and land
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Chapter 2 FAO, 1987. 1948-1985 Worl
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Chapter 2 Smeets, E., M. Junginger,
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Chapter 3 Considering that this deb
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Chapter 3 1,000 ha 9,000 8,000 7,00
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Chapter 3 Another source of data on
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Chapter 3 Figure 3. Different land
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Chapter 3 1-Pastureand crops expans
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Chapter 3 Given that the model is u
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Chapter 3 to the case studies; (d)
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Chapter 3 Mato Grosso do Sul in 200
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Chapter 3 the Pasture class increas
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Chapter 3 Table 5. Number of sugarc
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Chapter 3 of 12.6% from 2001 to 200
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Chapter 3 Table 6. South-Centre: ex
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Chapter 3 4.5. Options for approach
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Chapter 3 states that have lost pas
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Chapter 3 It is important to contex
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Chapter 4 Mitigation of GHG emissio
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Table 1. Basic data: sugarcane prod
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Mitigation of GHG emissions using s
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GHG emission (kg CO 2 eq/m 3 etOH)
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Table 7. Soil carbon content for di
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5. Conclusions Mitigation of GHG em
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Chapter 5 Oil reserves - Gasoline/d
Page 112 and 113: Chapter 5 in research and developme
Page 114 and 115: Chapter 5 Table 3. Summary of main
Page 116 and 117: Chapter 5 3. Environmental indicato
Page 118 and 119: Chapter 5 Table 4. Carbon stock in
Page 120 and 121: Chapter 5 3.2. Water Total carbon i
Page 122 and 123: Chapter 5 3.3. Soil and fertilizers
Page 124 and 125: Chapter 5 3.4. Management of diseas
Page 126 and 127: Chapter 5 Table 10. Sugarcane and v
Page 128 and 129: Chapter 5 in the implementation of
Page 130 and 131: Chapter 5 Table 11. Continued. Crit
Page 132 and 133: Chapter 5 Brazilian Government. Lei
Page 134 and 135: Chapter 5 São Paulo State Governme
Page 136 and 137: Chapter 6 2. Development of the eth
Page 138 and 139: Chapter 6 blends by car manufacture
Page 140 and 141: Chapter 6 Brazil have been roughly
Page 142 and 143: Chapter 6 Overall there are few di
Page 144 and 145: Chapter 6 3.2.1. The impact of exis
Page 146 and 147: Chapter 6 �e use of ethanol in he
Page 148 and 149: Chapter 6 cropping systems that pro
Page 150 and 151: Chapter 6 certainty, the supply of
Page 152 and 153: Chapter 6 De Vries, B.J.M., D.P. va
Page 155 and 156: Chapter 7 Biofuel conversion techno
Page 157 and 158: Biofuel conversion technologies �
Page 159 and 160: Biofuel conversion technologies In
Page 161: Biofuel conversion technologies the
Page 165 and 166: Biofuel conversion technologies Pro
Page 167 and 168: Investment costs (Euro/kWth input c
Page 169 and 170: 4.2. Greenhouse gas balances Biofue
Page 171 and 172: Reduction in CO equivalent emission
Page 173 and 174: Biofuel conversion technologies �
Page 175 and 176: Biofuel conversion technologies pot
Page 177 and 178: Chapter 8 The global impacts of US
Page 179 and 180: The global impacts of US and EU bio
Page 187 and 188: Table 1. Change in output due to EU
Page 191 and 192: Forest cover Pasture cover USEU 201
Page 193: The global impacts of US and EU bio
Page 196 and 197: Chapter 9 also risks and serious tr
Page 198 and 199: Chapter 9 Box 2. Bioethanol stoves
Page 200 and 201: Chapter 9 �e highest impact on po
Page 202 and 203: Chapter 9 the increased generation
Page 204 and 205: Chapter 9 o�ers to support the MD
Page 206 and 207: Chapter 9 Price variation (%) 14 12
Page 208 and 209: Chapter 9 Dufey et al., 2007a). Leg
Page 210 and 211: Chapter 9 manufactured directly fro
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Chapter 9 in mechanical aid for the
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Chapter 9 Table 1. Import tariffs o
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Chapter 9 3.8. Improving efficiency
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Chapter 9 some minimum transport in
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Chapter 9 IEA, 2004. Biofuels for T
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Chapter 10 Why are current food pri
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Why are current food prices so high
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2.4 Long-term drivers of supply Why
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3.1. Effects on the supply side Why
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3.3 Policy responses to rising food
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3.4. Other effects • Why are curr
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- - - - Why are current food prices
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18 16 14 12 10 8 6 4 2 0 5. The fut
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• • • Why are current food pr
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6.1. Policy implications Why are cu
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Why are current food prices so high
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Authors Dr. Marcos Adami, senior re
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Keyword index A Africa 204, 205, 20
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M maize 20, 83, 104, 173, 184, 187,
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