1 Introduction
2 Methodology
2.1 Process description and simulation
Fig. 1 Schematic diagram of the BECCS-PS for the co-production of green electricity and methanol |
2.1.1 The BIGCC unit
Fig. 2 Process flowsheet of the BIGCC |
Table 1 Proximate and ultimate analysis results of OPEFB [44] |
Component | Value |
---|---|
Proximate Analysis (%wt) | |
Moisture content | 5.18 |
Volatile matter | 82.58 |
Fixed carbon | 8.79 |
Ash | 3.45 |
Ultimate Analysis (%wt) | |
C | 46.62 |
H | 6.45 |
N | 1.21 |
S | 0.035 |
O | 45.66 |
Caloric Value (MJ/kg) | 17.02 |
2.1.2 Hydrogen production
Fig. 3 Process flowsheet of the PEM electrolyser |
2.1.2.1 Solar photovoltaics
Table 2 PV-battery system specifications |
Parameter | Value | Reference |
---|---|---|
PV efficiency (%) | 19.38 | [59] |
PV dimension (mm) | 2008 × 1002 × 40 | [59] |
PV capacity factor (%) | 12.7 | [60] |
Global horizontal irradiation (kWh/m2/day) | 4.96 | [61] |
Battery voltage | 380-505 | [62] |
Round-trip efficiency (%) | 90 | [62] |
Depth of discharge (%) | 100 | [62] |
Battery dimension (mm) | 7168 × 1659 × 2522 | [62] |
2.1.2.2 Geothermal power plant
2.1.3 Methanol synthesis
Fig. 4 Process flowsheet of methanol synthesis |
Table 4 Design parameters of the two-step methanol distillation process |
Parameter | Distillation I | Distillation II |
---|---|---|
Number of stages | 30 | 30 |
Feed stage | 15 | 15 |
Recycle stage | 1 | - |
Condenser type | Partial-vapor | Partial-vapor-liquid |
Reboiler type | Kettle | Kettle |
Reflux ratio (mole) | 1.1 | 6.8 |
Boil-up ratio (mole) | 2 | 5 |
Pressure (bar) | 1 | 1 |
Distillate vapor fraction (mass) | - | 0.01 |
2.1.4 Carbon capture and storage
Fig. 5 Flowsheet of the CCS unit: a absorption, b dehydration, and c compression and transport |
Table 5 The input operating parameters for CO2 capture |
Operating parameters | Value |
---|---|
Absorber | |
Column diameter (m) | 2.5 |
Height of packing (m) | 18 |
Structured packing | Mellapak 250Y |
Operating pressure (atm) | 1 |
Number of stages | 15 |
Stripper | |
Column diameter (m) | 4.3 |
Height of packing (m) | 20 |
Structured packing | Mellapak 250Y |
Operating pressure (atm) | 2 |
Number of stages | 10 |
Fig. 6 BECCS-PS plant area |
2.2 System evaluation
2.2.1 Technical assessment
2.2.2 Life cycle assessment
Table 6 LCA inventory data |
Activity | Value | Reference |
---|---|---|
OPEFB production | 0.168 kg CO2-eq/kg OPEFB | [79] |
Biomass transportation | 29 g CO2-eq/km/ton | [80] |
Deionized water production | 1.43 kg CO2-eq/m3 water | [81] |
Mono-cSi PV manufacturing | 45 g CO2-eq/kWh | [82] |
Li-ion battery manufacturing | 56.3 g CO2-eq/kWh | [83] |
Geothermal power plant emission | 3.88 g CO2-eq/kWh | [84] |
BIGCC electricity production | Simulation result | |
Hydrogen production | Simulation result | |
Methanol production | Simulation result | |
CCS unit | Simulation result |
2.2.3 Economic assessment
3 Results and discussion
3.1 Technical analysis
3.1.1 The BIGCC and CCS unit
Table 8 Technical performance of the BIGCC unit |
Parameter | Unit | Value |
---|---|---|
Ash content in syngas | mg/m3 | 0 |
H2S content in syngas | ppmv | 18.15 |
Tar content in syngas | mg/m3 | 0 |
Carbon conversion efficiency (CCE) | % | 99% |
Cold gas efficiency (CGE) | % | 60.40% |
H2/CO ratio of syngas | - | 0.59 |
LHV of syngas | Btu/scf | 277.13 |
Gas turbine efficiency | % | 35.63% |
Combined cycle total efficiency | % | 49.14% |
Overall efficiency | % | 29.68% |
Table 9 The final CO2 specification for pipeline |
Component | Unit | Value |
---|---|---|
CO2 | %v/v | 99.7 |
SO2 | ppmv | 1661.10 |
Nitrogen | %v/v | 0.006 |
Oxygen | ppmv | 1.22 |
H2O | ppmv | 37.63 |
3.1.2 Hydrogen production and methanol synthesis
Table 10 Technical performances of the hydrogen production and methanol synthesis processes |
Parameter | Unit | Value |
---|---|---|
Hydrogen production | ||
Energy usage | kWh/kg H2 | 53.75 |
H2O usage | kg/kg H2 | 9.39 |
Energy efficiency | % | 62 |
PV capacity | MWp | 1,894 |
Battery capacity | MWh/day | 3,496 |
PV land requirement | m2/kWp | 6.33 |
Geothermal heat requirement | MW | 2,072.46 |
Methanol production | ||
Electricity usage | kWh/kg MeOH | 0.218 |
CO2 usage | kg/kg MeOH | 1.41 |
H2 usage | kg/kg MeOH | 0.193 |
Overall CO2 conversion | % | 97.64 |
Overall H2 conversion | % | 100 |
Energy efficiency | % | 82.93 |
3.1.3 Overall technical performance
Fig. 7 Sankey diagram of the energy flow for all scenarios |
3.2 Life cycle analysis
Fig. 8 The CO2-eq emissions from different power plants |
Fig. 9 The CO2-eq emissions for methanol synthesis in all scenarios |
Fig. 10 Sankey diagrams of the carbon flow through the polygeneration system |
3.3 Economic analysis
3.3.1 The LCOE and CAC
Fig. 11 Levelized cost of electricity for all cases in the BIGCC unit |
Fig. 12 The CAC for both cases in the BIGCC unit |
3.3.2 LCOM
Fig. 13 Levelized cost of methanol in all scenarios |
3.3.3 Projection of levelized cost
Fig. 14 Projected levelized cost of methanol |