Thermodynamic modelling to optimise flue gas of a refinery furnace

The effect of flue gas including O-2, CO2, H2O, CO, and NOx on the characteristics of the flame and the amounts of pollutants emission were investigated. A set of equations based on Gibbs free energy and component balance was developed and solved using Quasi-Newton method to obtain the volume percentage of the flue gas components. The validity of the proposed model was confirmed with the field data obtained from the fluid catalytic cracking (FCC) with an average absolute relative deviation (AARD) of less than 2%. The effect of pressure and temperature was investigated on the volume percentage of the flue gas components. The results revealed that increasing pressure shifted the reactions toward the reactants, which produced less moles of NOx and CO2 gases and more moles of CO gaseous. Rising temperature increased the amount of NOx and CO gaseous and reduced the volume percentage of CO2 gaseous in the flue gas. [Received: September 16, 2020; Accepted: May 28, 2021]

Automated summary

The influence of flue gas composition (including O-2, CO2, H2O, CO, and NOx) on flame characteristics and pollutant emissions was investigated. A set of equations based on Gibbs free energy and component balance was developed to determine the volume percentage of flue gas components. The study confirmed the validity of the model using field data from a fluid catalytic cracking process, with an average absolute relative deviation of less than 2%. The results showed that pressure and temperature affected the volume percentage of flue gas components, with increased pressure reducing the formation of NOx and CO2 gases and increasing the formation of CO gas, and higher temperature increasing the amount of NOx and CO gases while reducing the volume percentage of CO2 gas.