PhD Thesis - Energy Systems Research Unit - University of Strathclyde

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