GPS-X Technical Reference

199 Suspended Growth Models
Estimate Airflow rate at Field Conditions
The airflow at standard conditions is converted to field conditions using the ideal gas law:
Equation 6.16
where:
T standard
T field
= air temperature at standard conditions (°C)
= air temperature at field conditions (°C)
Estimate the SAE
The SAE is estimated based on the correlation provided by Praxair. The expression is
valid for SOTE in the range of 86% to 100%. If the user specified SOTE is less than
80%, then SAE is bounded at 7.11 kg/kWh.
Equation 6.63
where:
SAE = Specific aerator energy (wire), kgO 2/kW-hr
SOTE = Standard oxygen transfer rate (%)
The mechanical power requirement is estimated using the following expression:
Equation 6.64
where:
P mechanical
SAE
= mechanical power (kW)
= mechanical aerator oxygen transfer rate (kg O2/kW·h)
CF 2 = conversion factor (24,000)
ηmotor
= motor efficiency
GPS-X Technical Reference