Biofuels in Perspective

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Bio-based Fischer-Tropsch Diesel Production Technologies 103 Figure 6.4 Two biomass-derived gases via gasification at different temperature levels. Reproduced by permission of ECN. hydrocarbons that have to be catalytically reformed. The second route generally requires temperatures as high as 1300 ◦ C and generally involves an entrained flow gasifier. Upon high temperature gasification (>1300 ◦ C) all the biomass is completely converted into biosyngas. Biosyngas is chemically similar to syngas derived from fossil sources and can replace its fossil equivalent in all applications. The two options concern two different evolution trajectories. The following paragraphs cover the two options. 6.3.3.1 Fluidized Bed Gasification with Catalytic Reformer Fluidized bed gasification of biomass presently is a common way of converting biomass. Many different technologies are available. The air-blown circulating fluidized bed (CFB) is the most common one. Most fluidized bed applications involve close-coupled combustion with little or no intermediate gas cleaning. Power and/or heat are the usual end products. The gas produced by a fluidized bed gasifier (typically operated at 900 ◦ C) contains H2, CO, CO2, H2O, and considerable amounts of hydrocarbons like CH4, C2H4, benzene and tars. Although this so-called product gas is suitable for combustion processes, it does not meet the requirements of synthesis gas, which is needed to produce biofuels or chemicals. The product gas needs further treatment in a catalytic reformer where hydrocarbons are converted into H2 and CO (and CO2 and H2O). Since most syngas to liquid fuels conversion processes require a raw gas with very little or no inert gases, gasification and reforming should apply pure oxygen instead of air. Steam is usually added as a moderator. Another option to avoid N2 dilution is to use an allothermal or indirect gasifier. In these reactors, gas production and heat generation do not take place in the same reactor. This enables the use of air (in the heat generating reactor), without having the N2-dilution of the gas coming from the gas generation reactor. Examples of indirect gasifiers are: the SilvaGasprocess developed by Battelle in the US, 16 the MTCI-process, 17 the MILENA developed by the Energy research Centre of the Netherlands (ECN), 18,19 and the FICFB-concept developed by the Vienna University 20 and in operation at the Biomass-CHP in Güssing. The FICFB based biomass-CHP plant in Güssing is one of the facilities (as well as the Choren and Chemrec plants discussed in Sections 6.3.4.5 and 6.3.4.6) have been used in the EU-funded project RENEW. Within this project production routes for BTL fuels have
104 Biofuels been demonstrated and the full supply chain was assessed in terms of biomass potential, life-cycle, costs and technological options. Fuels were be produced and tested in order to demonstrate benefits of optimized fuels for advanced power trains. In the EU-funded project Chrisgas, the existing 18 MWth pressurized CFB-gasifier in Värnamo will be refurbished to produce syngas. 21 This includes operation on oxygen/steam instead of air, the installation of a high temperature filter, a catalytic reformer, and a shift reactor. In five years time, the plant should produce 3500 mn 3 /h H2 and CO at 10 bar. The project is carried out by the VVBGC consortium (Växjö Värnamo Biomass Gasification Centre). In the next phase, fuel synthesis will be added to the plant. Another initiative in this category is by VTT that advocates fluidized bed gasification as the process to generate clean fuel gas as well as syngas from biomass. Fuel flexibility is considered the major advantage. VTT started the UCG-programme (Ultra Clean Fuel Gas) and a 500 kWth PDU is operating. 22 It consists of a pressurized fluidized bed, catalytic reforming, and further cleaning and conditioning. The catalytic reformer is meant to reduce hydrocarbons (benzene and larger) completely and methane by over 95 %. The test unit will support RD&D focusing on methanol and FT-diesel production via syngas as well as the production of SNG, H2, and electricity by fuel cells. The present estimate of a 300 MWth plant based on above described VTT process show that FT-diesel and methanol can be produced for approximately 12 €/GJ (feedstock price 2.8 €/GJ). A plant this size can be largely constructed as a single train. The German institute CUTEC has constructed an oxygen-blown 0.4 MWth CFB gasifier connected to a catalytic reformer. Part of the gas is compressed and directed to a FTsynthesis reactor. 23 Apart from these above-mentioned initiatives to develop technology to produce syngas by fluidized bed gasification and catalytic reforming, many others apply catalytic reforming reactors for gas conditioning. This, however, generally focuses on the catalytic reduction of large hydrocarbon molecules (viz. tars). Reforming of methane usually is not one of the goals in these concepts. 6.3.3.2 Entrained Flow Gasification The non-catalytic production of syngas (H2 and CO) from biomass generally requires high temperatures, typically 1300 ◦ C. The most common reactor for this is the entrained flow gasifier. 24 Since biomass contains mineral matter (ash), a slagging entrained flow gasifier seems to be the most appropriate technology. 25 Entrained flow reactors need very small fuel particles to have sufficient conversion. This requires extensive milling of solid fuels, which is energy intensive and generally produces particles that cannot be fed by conventional pneumatic systems. 25 R&D therefore focuses on ways to technically enable the fuel feeding, as discussed in Section 6.3.4, as well as on the improvement of the economics of the whole chain. The most promising pre-treatment options are torrefaction and pyrolysis. These options enable efficient and cheap production of syngas from biomass, mainly because it is characterized by relatively cheap (long-distance) transport. Different slagging entrained flow gasifiers are operated worldwide, but only few have experience with biomass. Former Future Energy, now Siemens, in Freiberg Germany commercializes entrained flow gasifier technology for biomass, waste, and other fuels. 26 It owns a 3 MWth pilot plant that has been operated with many different biomass fuels.
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Biofuels Biofuels. Edited by Wim So
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Biofuels Edited by WIM SOETAERT Ghe
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Contents Series Preface ix Preface
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Contents vii 6.3 Biomass Gasificati
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Series Preface Renewable resources,
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Preface This volume on Biofuels fit
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Editors List of Contributors Wim So
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1 Biofuels in Perspective W. Soetae
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Table 1.1 Approximate average world
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Table 1.3 Energy yields of bio-ener
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Biofuels in Perspective 7 is burnt
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2 Sustainable Production of Cellulo
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Sustainable Production of Cellulosi
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Figure 2.9 2004 US adoption rates o
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3 Bio-Ethanol Development in the US
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Bio-Ethanol Development in the USA
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Biorefineries in Production (115) B
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Cost of Cellulosic Ethanol, $ per g
Page 68 and 69: Bio-Ethanol Development in the USA
Page 70 and 71: 4 Bio-Ethanol Development(s) in Bra
Page 72 and 73: Bio-Ethanol Development(s) in Brazi
Page 74 and 75: Share of energy consumption 100% 90
Page 80 and 81: Table 4.2 Main technological improv
Page 84 and 85: 4.7.4 Use of Fertilizers and Pestic
Page 90: Bio-Ethanol Development(s) in Brazi
Page 93 and 94: 78 Biofuels Table 5.1 Biodiesel pro
Page 95 and 96: 80 Biofuels CH 2 O CH O COR R1 + 3
Page 97 and 98: 82 Biofuels short reaction times. 9
Page 99 and 100: 84 Biofuels Table 5.4 Overview on h
Page 101 and 102: 86 Biofuels Table 5.5 Critical cond
Page 103 and 104: 88 Biofuels methoxide as catalyst u
Page 105 and 106: 90 Biofuels KOH Methano Oil/Fat Aci
Page 107 and 108: 92 Biofuels 16. J. Graille, P. Loza
Page 110 and 111: 6 Bio-based Fischer-Tropsch Diesel
Page 112 and 113: 6.2.1.2 Catalysts Bio-based Fischer
Page 114 and 115: Bio-based Fischer-Tropsch Diesel Pr
Page 132 and 133: 7 Plant Oil Biofuel: Rationale, Pro
Page 134 and 135: Table 7.1 Market milestones for pla
Page 136 and 137: Water CO 2 Figure 7.1 Closed CO 2 l
Page 138 and 139: Plant Oil Biofuel: Rationale, Produ
Page 140 and 141: Plant Oil Biofuel: Rationale, Produ
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Page 145 and 146: 130 Biofuels Among the attractive f
Page 147 and 148: 132 Biofuels Table 8.1 Enzymatic tr
Page 149 and 150: 134 Biofuels conversion was maintai
Page 151 and 152: 136 Biofuels (diglycerides) decreas
Page 153 and 154: 138 Biofuels ME content (wt.%) Reac
Page 155 and 156: 140 Biofuels Ratio of initial react
Page 157 and 158: 142 Biofuels (a) 34 kDa 31 kDa 34 k
Page 159 and 160: 144 Biofuels preparation of whole-c
Page 161 and 162: ability to reduce flocculation (% o
Page 163 and 164: 148 Biofuels 5. R. C. Strayer, J. A
Page 165 and 166: 150 Biofuels 46. H. Fukuda, Immobil
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9 Production of Biodiesel from Wast
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Production of Biodiesel from Waste
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9.3.2 Processing of Crude and Waste
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Heavy layer from alkaline neutralis
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CPO I 1 1 Heating 60°C Reaction st
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References Production of Biodiesel
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10 Biomass Digestion to Methane in
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Cow manure Pig manure Yard manure B
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Number of plants 3000 2500 2000 150
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Biomass Digestion to Methane in Agr
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Table 10.4 Alternative forms of ene
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Wet fermentation 3 - 10% TS applica
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Rel. Frequency [%] 35 30 25 20 15 1
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Steam 2 1 Energy crops (& manure) D
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198 Biofuels 11.1 Introduction Hydr
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200 Biofuels lactate 6 glucose 1 GA
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Table 11.2 Continued Organism Domai
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204 Biofuels NADH is that the react
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206 Biofuels Clostridium thermocell
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208 Biofuels in particular in Cl. p
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210 Biofuels ferredoxin-dependent m
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212 Biofuels Concentration (mM) 45
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214 Biofuels genes of the glycolysi
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216 Biofuels 11. S. Tanisho and Y.
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218 Biofuels 49. M. J. Axley, D. A.
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220 Biofuels 83. P. J. Silva, E. C.
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12 Improving Sustainability of the
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Table 12.1 Corn ethanol dry mill: e
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Table 12.2 Atmospheric CO2 (equival
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Table 12.3 Incremental CO2 equivale
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Improving Sustainability of the Cor
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Improving Sustainability of the Cor
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Index italic entries indicate refer
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iorefineries 3, 10, 11, 41 and corn
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policy (official) 59-61 production
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NADH 200-6, 207, 210 natural gas 1
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