Industrial Gases, Cryogenic Distillation & Steel/Gasification Utilities
Cryogenic Air Separation Unit (ASU) Oxygen & Power Formula
Calculate Cryogenic ASU Dry-Air Intake Flow (Nm³/hr), Daily Pure Oxygen Tonnage (t/day), Main Air Compressor Power (MW), and Total Pipeline GOX Electrical Load (MW).
Account for 20.95% dry-air oxygen fraction AND distillation recovery—never 100% O2 capture!
In a Linde-type double-column cryogenic Air Separation Unit (ASU) supplying 99.6% gaseous oxygen (GOX) to basic oxygen steelmaking, oxy-combustion, or autothermal reforming, dry CO2-free air enters the cold box containing 20.95 vol% O2 (78.12% N2, 0.93% Ar). Because side-draw argon rectification and low-pressure nitrogen regeneration vent 3%–8% of incoming oxygen, Required Dry Air Intake is Q_air = Q_GOX / (0.2095 * O2_Recovery_Fraction)! Sizing the Main Air Compressor (MAC) on 100% stoichiometric capture starves the high-pressure column!
Verify on a Large Steelworks ASU—Pure_GOX_Output = 40,224 Nm³/hr (0°C, 1 atm, B2), Column_O2_Recovery = 0.96 (96.0%, B3 -> Dry Air Feed = 40,224 / (0.2095 * 0.96) = 200,000.00 Nm³/hr in E2), ColdBox_MAC_Specific_Power = 0.40 kWh/Nm³ O2 (B4), and GOX_Pipeline_Booster_Power = 0.15 kWh/Nm³ O2 at O2 density 1.429 kg/Nm³ (B5): Daily Pure Oxygen Production equals 40,224 * 1.429 * 24 / 1,000 = 1,379.52 metric tons/day (E3), Main Air Compressor Power is 16.09 MW (E4), and Total ASU + Pipeline Booster Load hits 22.12 MW (E5)!
| Cryogenic ASU Plant KPI (40,224 Nm³/hr GOX, 96% Recovery, 0.40+0.15 kWh/Nm³) | Formula | Verified Output |
|---|---|---|
| Dry Air Intake Required (Nm³/hr) | GOX_Nm3_hr / (0.2095 * O2_Recovery) | 200,000.00 Nm³/hr (213,333.33 @ 90%) |
| Daily Oxygen Tonnage (t/day) | GOX_Nm3_hr * 1.429 * 24 / 1000 | 1,379.52 t/day |
| Main Air Compressor Load (MW) | GOX_Nm3_hr * MAC_kWh_Nm3 / 1000 | 16.09 MW |
| Total ASU + Booster Power (MW) | GOX_Nm3_hr * (MAC_kWh + Boost_kWh) / 1000 | 22.12 MW |
Cryogenic ASU Dry-Air Intake & Compressor MW Formula
Validate GOX_Flow > 0, O2_Recovery in (0.50, 1.0], MAC_Specific_Power > 0, and Booster_Specific_Power >= 0!
=LET(gx_q, B2, rc_o, B3, mc_k, B4, bs_k, B5, IF(OR(gx_q <= 0, rc_o <= 0.5, rc_o > 1, mc_k <= 0, bs_k < 0), "Invalid ASU Plant Input", ROUND(gx_q / (0.2095 * rc_o), 2)))High-Argon Recovery O2 Slippage Check (Set Column O2 Recovery = 0.90)
Lower Column_O2_Recovery B3 from 0.96 to 0.90 (pushing argon recovery or operating with maldistributed structured packing): Required Dry Air Intake E2 climbs by +13,333.33 Nm³/hr to 213,333.33 Nm³/hr!
=IF(ISTEXT(E2), E2, ROUND(B2 * (B4 + B5) / 1000, 2))Try the example
Use the original values or change them to test your understanding.