Emission monitoring and control of flare systems

A system for controlling a flare, comprising:

• a memory configured to maintain:
• a first model configured to estimate a net heating value of a combustion gas within a combustion zone of a flare based on one or more operating parameters comprising measured volumetric flow rates of a flare gas, a supplemental fuel gas, and an assist gas;
• a second model configured to estimate a combustion efficiency of the combustion gas based on the one or more operating parameters;
• and
• a third model configured to estimate a smoke yield resulting from combustion of the combustion gas based on the one or more operating parameters;
• and
• at least one processor in communication with the memory and configured to perform a plurality of operations including:
• receiving the one or more operating parameters;
• receiving the first, second, and third models from the memory;
• determining a set point for respective volumetric flow rates of at least one of the supplemental fuel gas or the assist gas, based upon the first model, the second model, and the third model, that achieves a target combustion efficiency;
• and
• determining a difference between each determined set point and its corresponding measured volumetric flow rate for the supplemental fuel gas and the assist gas,
• wherein, responsive to the difference being greater than a predetermined tolerance amount, the at least one processor is further configured to output at least one command signal operative to command a flow regulator to adjust the volumetric flow rate of at least one of the supplemental fuel gas or the assist gas to reduce the difference below the predetermined tolerance amount.