PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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No Is i between process times ? Factor = Stor x Timesteps / FeedUse No No No No Gas = Pyr = Char = CH4 = H2 = CO = CO2 = Methanol = 0 No Yes Is process 24 hrs ? Yes No No Outputs No Is Stor >= Min Yes / Timesteps ? Yes Yes Yes Is Stor >= FeedUse / Timesteps ? Yes Factor = 1 Stor = Stor - ( Factor x FeedUse / Timesteps) Elec = Elec + ElecUse Heat = Heat + ( Factor x Heat Use ) Pyr = Factor x 1 000 x PyrMade / PyrDensity Char = Factor x CharMade Gas = Factor x GasMade / GasDensity Keep as low heating value biogas ? Keep as medium heating value biogas ? Separate hydrogen and methane components ? Process methane to hydrogen via steam reforming ? Process biogas to methanol via catalytic synthesis Yes Is electricity required to compress gas for storage ? Yes Is electricity required to compress gas for storage ? Yes H2 = Gas x Hyd / 100 CH4 = Gas x Meth / 100 Is electricity required to compress CH4 ? Yes H2 = Gas x Hyd x 0.08988 / 100 CH4 = Gas x Meth x 0.714 / 100 CO = Gas x Monox x 1.25 / 100 CO2 = Gas x Diox x 1.964 / 100 Methanol = Percent x 1 .1 43 x CO / ( 0.79 x 1 00) H2 = H2 - Percent x 0.143 x CO / 100 Is CO2 >= 7.33 x H2 ? No Yes Methanol = Methanol + Percent x 0.727 x CO / ( 0.79 x 1 00) H2 = H2 - Percent x 0.136 x CO / 100 No Biogaslow = Low Heating Value Biogas Production Rate (kW) Biogasmed = Medium Heating Value Biogas Production Rate (kW) CH4 = 95% Methane Production Rate (kW) H2 = Hydrogen Production Rate (kW) CO = Carbon Monoxide Production Rate (kg/hr) CO2 = Carbon Dioxide Production Rate (kg/hr) Methanol = Methanol Production Rate (litres) FeedUse = Maximum Feedstock Feed Rate (kg/hr) Min = Minimum Feedstock Feed Rate (kg/hr) Timesteps = Number of Timesteps per Hour ElecUse = Electricity Required for the Process (kW) HeatUse = Heat Required for the Process (kW) PyrMade = Pyrolysis Oil Production Rate (at Max) (kg/hr) CharMade = Charcoal Production Rate (at Max) (kg/hr) GasMade = Biogas Production Rate (at Max) (kg/hr) PyrDensity = Pyrolysis Oil Density (kg/m3) GasDensity = BiogasDensity (kg/m3) GasLHV = Lower Heating Value of Biogas (kJ/m3) ElecComp = Electricity Required to Compress Biogas or Methane for Storage (kWh/m3) ElecComp2 = Electricity Required to Compress Hydrogen for Storage (kWh/m3) Hyd = % volume of Hydrogen in Biogas Mixture Meth = % volume of Methane in Biogas Mixture Monox = % volume of Carbon Monoxide in Biogas Mixture Diox = % volume of Carbon Dioxide in Biogas Mixture Percent = Percentage Completion of Catalytic Synthesis Reaction PercentSR = Percentage Completion of Steam Reforming Reaction Elec = Elec + ElecComp x Gas No Elec = Elec + ElecComp x Gas No 184 Gas = Gas x GasLHV / 361 0.3 Gas = Gas x GasLHV / 3610.3 Is electricity required to compress H2 ? Elec = Elec + ElecComp x CH4 Yes No Elec = Elec + ElecComp2 x H2 H2 = Gas x Hyd x 0.08988 / 100 CH4 = Gas x Meth x 0.714 / 100 H2 = ( H2 - PercentSR x CH4 x 0.446 / 100 ) / 0.08988 CH4 = ( CH4 - PercentSR x CH4 / 100 ) / 0.714 No Is steam Yes reforming taking place ? No Is CO >= 7 x H2 ? Can extra CO2 be used ? Figure 6.3 Gasification and Pyrolysis Algorithm No Yes Biogaslow = Gas Biogasmed = Gas H2 = H2 x 12600 / 3610.3 CH4 = CH4 x 35800 / 3610.3 H2 = H2 + PercentSR x CH4 x 0.446 / 1 00 CO = CO + PercentSR x CH4 x 0.878 / 1 00 CO2 = CO2 + PercentSR x CH4 x 1.378 / 100 CH4 = CH4 - PercentSR x CH4 / 1 00 Methanol = Percent x 8 x H2 / ( 0.79 x 100) H2 = H2 - Percent x H2 / 1 00 Yes LHV of H2 = 12600 kJ/ m3 LHV of CH4 = 35800 kJ/ m3 Density of H2 = 0.08988 kg/ m3 Density of CH4 = 0.714 kg/ m3 Density of CO = 1.25 kg/ m3 Density of CO2 = 1.964 kg/ m3 Density of Methanol = 0.79 kg/ litre Methanol = Methanol + Percent x 5.33 x H2 / ( 0.79 x 100) H2 = H2 - Percent x H2 / 1 00
6.1.3 Use of Biogas Various options are available for the use of the biogas produced. The algorithms described are shown graphically in Figure 6.3. 1. Keep as a low or medium heating value biogas The biogas production rate is calculated using Equation 6.4 (applying the partial production factor as necessary), which calculates the rate of production of biogas by measuring its energy content (kW). If this gas is to be put into storage, the electricity required to do this is calculated using, Electricity Required (kW) = Biogas x Elec (6.7) GasDensity Where Biogas = Biogas production rate (kg/hr) Elec = Electricity to compress or liquefy biogas (kWh/Nm 3 ) GasDensity = Density of biogas (kg/Nm 3 ). 2. Separate the hydrogen and methane components The composition of the biogas produced from a specific process and feedstock is generally quoted as the percentage, by volume, of specific important gases in the total mixture. The amount of a specified gas in the mixture is, therefore, calculated using Equation 6.8, and the electricity required to put either or both gases into storage, if required, is calculated using Equation 6.9. The partial production factor is applied as necessary. Specified Gas = Biogas x Percentage x LHV (6.8) Production Rate (kW) GasDensity x 100 x 3610.3 Electricity Required (kW) = Biogas x Percentage x Elec (6.9) GasDensity x 100 Where Biogas = Biogas production rate (kg/hr) Percentage = Percentage of specified gas in mixture (by volume) 185
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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
Page 133 and 134: Is PL < Min ? No Is PL = 0 ? No Is
Page 135 and 136: where Max = maximum energy availabl
Page 137 and 138: where Ratiopart = heat to electrici
Page 139 and 140: (including following heat demand wh
Page 141 and 142: where SFC = specific fuel consumpti
Page 143 and 144: engines running respectively). If t
Page 145 and 146: (continued) Is Fuel Available > (4
Page 147 and 148: of the definition window for a Stir
Page 149 and 150: and continuous operation. Again, mu
Page 151 and 152: The performance of a fuel cell is n
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: Where Biogas = Biogas production ra
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 and 200: (continued) Keep as medium heating
Page 201 and 202: Yes Feed1 = Yield1 x Land1 / No. of
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
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Figure 7.16 Anaerobic Digestion Par
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Figure 7.19 Fermentation System Inp
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clarity. A constant supply rate of
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Figure 7.25 Heat Demand Profile Fig
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Figure 7.28 Effect of Minimum Load
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esidual heat demand as this would r
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Figure 7.35 Second Engine: Followin
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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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