PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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6.3 Transesterification Transesterification is the production of methyl or ethyl esters (biodiesel) from animal or vegetable oils. The feedstock for this process may be continuously available (waste vegetable or animal oils), or seasonal (energy crops). Smallscale production is batch-wise, and larger scale continuous processes are being developed [7]. An example of the transesterification system definition window is given in Appendix 1, Figure A1.16. 6.3.1 Feedstock Availability Feedstock availability, for continuous and seasonal supplies, is dealt with in a similar manner to that described in Section 6.1.1. For seasonal supplies, the oil availability per day is calculated using Equation 6.3, where the crop yield is in litres of oil per hectare. The electricity and heat required for oil extraction from energy crops, if necessary, are calculated using Equation 6.1 or 6.2 (substituting the heat requirement where appropriate), and are applied during the appropriate times. As it is common to use the same equipment to process oils from different harvest crops at different times of the year, to allow a more continual use, up to five different seasonal supplies may be defined for use by the same processing equipment. These are all added into the same store, as they become available, as the performance of the processing equipment and process requirements are not significantly affected by the use of different feedstocks. This process is shown in Figure 6.5. Again, the rate of use of oil from seasonal supplies may be slower than the production rate to allow fuel production beyond the harvest periods. For seasonal supplies, if there is excess feedstock left over in the store at the end of the simulation period, and this is more than the minimum required for the fuel production process, the entire simulation period is analysed again, and the results from this second simulation period are used. 200
Yes Feed1 = Yield1 x Land1 / No. of harvest Days Feed2 = Yield2 x Land2 / No. of harvest Days Feed3 = Yield3 x Land3 / No. of harvest Days Feed4 = Yield4 x Land4 / No. of harvest Days Feed5 = Yield5 x Land5 / No. of harvest Days Residue1 = Res1 x Land1 / No. of harvest Days Residue2 = Res2 x Land2 / No. of harvest Days Residue3 = Res3 x Land3 / No. of harvest Days Residue4 = Res4 x Land4 / No. of harvest Days Residue5 = Res5 x Land5 / No. of harvest Days No No Determine date using i value Is j = TS - 1 ? Is date between or on harvest dates ? Yes St or = St or + Feed1 Residue = Residue + Residue1 Yes Yes Is feedstock availability seasonal ? No j = i Is j > TS - 1 ? No Elec = 0 Heat = 0 Yes Is feedstock availability seasonal ? Stor = Stor - ( Stor x Degrade / 1 00) Yes Elec = Feed1 x OilElec1 / 24 Heat = Feed1 x OilHeat1 / 24 Yes Is electricity for oil extraction required 24 hrs ? Is j = TS - 1 ? Elec = Feed1 x OilElec1 / No. of hours for processing per day Heat = Feed1 x OilHeat1 / No. of hours for processing per day Repeat process in dashed box for other harvest periods as appropriate, using the specific values for each different period Yes No No Is j between stated times ? No 201 j = j - TS No Feed = Amount of Feedstock Available (kg/day) (Continuous Supply) Feed1 = Amount of Feedstock Available in Time Period 1 (litres/day) Yield1 = Crop Yield (litres of oil / ha) Land1 = Land Avalable for Period 1 Crop (ha) Res1 = Crop Residue Available in Period 1 (kg / ha) Residue1 = Crop Residue Available in Time Period 1 (kg/day) OilElec1 = Electricity Required for Oil Extraction for Period 1 (kW/litre) OiHeat1 = Heat Required for Oil Extraction for Period 1 (kW/litre) Stor = Amount of Stored Oil (litres) Residue = Amount of Stored Residue (kg) Yes Is j = 0 and i > 0 ? St or = St or - ( St or x Degrade / 1 00) No Yes Stor = Stor + Feed Is Stor > MaxStor ? (Figure 6.6) Is j = 0 ? Figure 6.5 Transesterification Feedstock Availability Algorithm Yes No No MaxStor = Stor
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Decision Support for New and Renewa
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Abstract The global requirement for
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CONTENTS 1 ENERGY SYSTEMS FOR SUSTA
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5.5 Steam Turbine Model 149 5.6 Fue
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FIGURES Figure 1.1 Final Energy Con
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Figure 7.30 Following Electricity a
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on the use of fossil fuels, energy
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The general increase in energy cons
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supply is reduced or eliminated, lo
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Figure 1.3 The Electricity Supply G
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on different generation mixes depen
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Various studies have been carried o
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provision for smaller areas, and he
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1.7 References [1] The Internationa
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2 Options for New and Renewable Ene
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the amount of usable heat that is g
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the conversion of petrol cars; howe
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set times, producing a constant ele
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partial load. Fast response and sta
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2.3 The Production and Storage of H
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dedicated boiler, which runs contin
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Figure 2.3 A Typical Hydrogen Filli
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part of the natural carbon cycle (a
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Figure 2.4 Layout of a Gasification
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met by process integration and the
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Figure 2.5 The Inputs and Outputs o
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1. Scale for measuring out lye and
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feedstock being used. Sugary feedst
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carbon dioxide via steam reforming.
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• Where CHP is used, the balance
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[22] Vehicle Certification Agency (
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[55] M. A. Paisley, J. M. Irving, R
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3 Approaches to Renewable Energy Sy
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Because of the intermittent nature
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A renewable energy supply evaluatio
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the system are kept. The output of
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There are various models available
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When the use of climate dependant i
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3.5 References [1] M. Muselli, G. N
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4 A Procedure for Demand and Supply
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pumped storage and flywheels), a ba
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for the agricultural vehicle use re
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Figure 4.4 Combining Demands to Tak
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ates for vehicles, engines and othe
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Figure 4.5 Derived Fuel Production
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together if desired, and taken forw
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profiles are output from this part
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dividing the production rate at eac
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As it would be too confusing to sho
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Figure 4.12 Output of the Matching
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However, when more than one transpo
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considered, this amount is added to
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users are alerted if there is not e
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at the matching stage, along with t
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vehicles if they are increased by 1
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If biogas is being considered, the
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The number of timesteps per hour wi
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After the algorithm has been follow
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• Float Charge - once the battery
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Discharge No tank = tank fuel used
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equired (kW) = maxkWh x bulk% (5.16
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An example of the output graph prod
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5.2.1 Required Power Specifically d
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5.2.3 Engine Performance in the Con
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used for gas powered ICEs, but the
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and five times, depending on the nu
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Is PL < Min ? No Is PL = 0 ? No Is
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where Max = maximum energy availabl
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where Ratiopart = heat to electrici
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(including following heat demand wh
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where SFC = specific fuel consumpti
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engines running respectively). If t
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(continued) Is Fuel Available > (4
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of the definition window for a Stir
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Page 153 and 154: percentage loading, rather than usi
Page 155 and 156: Is Min = 0 ? No Is Min = PC1 ? No I
Page 157 and 158: 5.6.4 If Fuel Availability is Less
Page 159 and 160: 5.7 Electrolyser Model An electroly
Page 161 and 162: original calculation of the amount
Page 163 and 164: 5.8 Regenerative Fuel Cell Model A
Page 165 and 166: following the heat demand. To follo
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Page 169 and 170: As 1 kWh = 3610.3 kJ, and using lit
Page 171 and 172: Add Heat to Water Storage Tank Usin
Page 173 and 174: Use Stored Hot Water to Supply Heat
Page 175 and 176: information is given about the over
Page 177 and 178: [23] K. Foger, B. Godfrey, “Syste
Page 179 and 180: the gasification and pyrolysis defi
Page 181 and 182: eing used each day for a continuous
Page 183 and 184: Where Biogas = Biogas production ra
Page 185 and 186: 6.1.3 Use of Biogas Various options
Page 187 and 188: The amount of hydrogen that can be
Page 189 and 190: direct proportion, and the weight o
Page 191 and 192: produce in total (Nm 3 per tonne fe
Page 193 and 194: Electricity (kW) = Elec x Feed (6.1
Page 195 and 196: 3. Make hydrogen via steam reformin
Page 197 and 198: Where Methane = Methane Production
Page 199: (continued) Keep as medium heating
Page 203 and 204: production and energy use profiles
Page 205 and 206: If it is the last timestep of the p
Page 207 and 208: For each process, the process chara
Page 209 and 210: At the end of the simulation, graph
Page 211 and 212: As the time required for one batch
Page 213 and 214: Ethanol = Factor1 x Eth x Timesteps
Page 215 and 216: 6.5 Electrolysis As it is sometimes
Page 217 and 218: 6.7 Landfill Gas Processing As the
Page 219 and 220: Demand Profile Design & Profile Dat
Page 221 and 222: Figure 7.2 Degree-Days Versus Month
Page 223 and 224: Stage 1 - Sustainable Fuel Supply S
Page 225 and 226: The different profile of use graphs
Page 227 and 228: Figure 7.3 Fermentation System Inpu
Page 229 and 230: Figure 7.7 Fermentation System Info
Page 231 and 232: Figure 7.10 Fermentation System Out
Page 233 and 234: The output obtained when a second h
Page 235 and 236: Figure 7.16 Anaerobic Digestion Par
Page 237 and 238: Figure 7.19 Fermentation System Inp
Page 239 and 240: clarity. A constant supply rate of
Page 241 and 242: Figure 7.25 Heat Demand Profile Fig
Page 243 and 244: Figure 7.28 Effect of Minimum Load
Page 245 and 246: esidual heat demand as this would r
Page 247 and 248: Figure 7.35 Second Engine: Followin
Page 249 and 250: This chapter described how the over
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heat and electricity during the tou
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Figure 8.2: Overall Yearly Heat Dem
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to allow for efficient operation du
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would be incurred, and the scale of
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Figure 8.5: Electricity Supply and
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heat demand or both, or run at cons
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ut with 30% less land being require
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9 Conclusions and Recommendations T
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through these, technically viable p
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considered. The introduction of coo
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When considering larger geographica
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Appendix 1: Program Windows Figure
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Figure A1.5 CreateClimate.exe Figur
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Figure A1.9: Demand Profile Designe
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Figure A1.13: Derived Fuel Supply W
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Figure A1.17: Fermentation System D
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Figure A1.21: PV Electrolysis Syste
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Figure A1.25: Fuel Supply Profile D
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Figure A1.29: Auxilliary Supply Def
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Figure A1.33: Stirling Engine Syste
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Figure A1.37: Fuel Cell System Defi
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Figure A1.41: Electric Vehicle Syst
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Figure A1.45: Vehicle Conversion Fa
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Figure A1.49: Heating System Defini
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Figure A1.53: Pumped Hydro System D
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Figure A1.57: Auto Search Evaluatio
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PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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