Hydrogen Engineering, Chemical Process Synthesis & Carbon Capture
Steam-Methane Reforming (SMR) H2 & Blue CO2 Intensity Formula
Calculate SMR Hydrogen Plant Total Methane Demand (t/day), Net Specific CO2 Intensity (kg CO2 / kg H2), Daily Captured CO2 Sequestered (t/day), and Residual Stack Emissions (t/day).
Grey SMR emits ~9.9 kg CO2/kg H2—not stoichiometric 5.5—because of radiant-box burner fuel!
Students writing overall Steam-Methane Reforming + Water-Gas Shift stoichiometry (CH4 + 2 H2O -> CO2 + 4 H2; 16 kg CH4 -> 44 kg CO2 + 8 kg H2, or 2.75 kg CO2 per kg CH4) often claim grey hydrogen emits only 44 / 8 = 5.50 kg CO2/kg H2! In a real industrial SMR + Pressure-Swing Adsorption (PSA) plant, non-ideal conversion requires ~2.40 kg Process Feed CH4/kg H2 (6.60 kg process CO2/kg H2) AND the strongly endothermic reforming tubes (+206 kJ/mol) require ~1.20 kg Burner Fuel CH4/kg H2 (3.30 kg low-pressure furnace flue CO2/kg H2)—totalling 9.90 kg CO2/kg H2! Crucially, pre-combustion amine capture on high-pressure shifted syngas captures ONLY the 6.60 kg process stream, leaving 3.96 kg CO2/kg H2 unless post-combustion flue-gas capture is added!
Verify on a 200 t/day Grey SMR Baseline—Plant_H2_Output = 200 t/day (B2), Process_Feed_CH4 = 2.40 kg/kg H2 (B3), Furnace_Fuel_CH4 = 1.20 kg/kg H2 (B4 -> Total Methane = 200 * 3.60 = 720.00 t/day in E2), Syngas_Amine_Capture = 0.00 (B5), and FlueGas_Capture = 0.00 (B6): Specific Carbon Intensity equals (2.40 + 1.20) * 2.75 = 9.90 kg CO2/kg H2 (E3), Captured CO2 is 0.00 t/day (E4), and Stack Emissions hit 1,980.00 t/day (E5)!
| SMR Hydrogen Carbon-Balance KPI (200 t/d H2, 2.40 Feed + 1.20 Fuel CH4) | Formula | Verified Output |
|---|---|---|
| Total Methane Feed + Fuel (t/d) | H2_t_day * (Feed_CH4 + Fuel_CH4) | 720.00 t/d |
| Net Carbon Intensity (kg CO2/kg H2) | 2.75 * (Feed*(1-Cap_Syn) + Fuel*(1-Cap_Flue)) | 9.90 (3.96 Syngas CCS; 0.99 Dual) |
| Captured CO2 Sequestered (t/d) | H2_t_day * 2.75 * (Feed*Cap_Syn + Fuel*Cap_Flue) | 0.00 t/d (1,188.00 Syngas; 1,782 Dual) |
| Residual Stack CO2 Emitted (t/d) | H2_t_day * Net_Carbon_Intensity | 1,980.00 t/d (792.00; 198.00) |
Dual-Stream SMR Process + Furnace Carbon Intensity Formula
Validate H2_Output > 0, Process_CH4 >= 2.0 (stoichiometric floor 16/8!), Furnace_CH4 >= 0, and both Capture_Fractions in [0, 0.99]!
=LET(h2_t, B2, ch_p, B3, ch_f, B4, cp_s, B5, cp_g, B6, IF(OR(h2_t <= 0, ch_p < 2, ch_f < 0, cp_s < 0, cp_s > 0.99, cp_g < 0, cp_g > 0.99), "Invalid SMR Plant Input", ROUND(2.75 * (ch_p * (1 - cp_s) + ch_f * (1 - cp_g)), 2)))Syngas-Only Amine Capture vs Full Dual-Stream Blue-H2 Checks
Enable 90% pre-combustion syngas capture alone (B5 = 0.90, B6 = 0.00): Intensity E3 drops from 9.90 to 3.96 kg CO2/kg H2 (1,188.00 t/d captured E4)—still missing strict < 2.0 clean-hydrogen tax thresholds! Now add 90% post-combustion flue capture (B5 = 0.90, B6 = 0.90): Intensity E3 plunges to 0.99 kg CO2/kg H2 (1,782.00 t/d captured E4, 198.00 t/d emitted E5)!
=IF(ISTEXT(E3), E3, ROUND(B2 * 2.75 * (B3 * B5 + B4 * B6), 2))Try the example
Use the original values or change them to test your understanding.