(210a) Using modeling to control a chemical plant flare

In a chemical plant, a flare is often used to dispose of production waste by-products. The heating value of the waste products is often not high enough for them to burn at the target combustion temperature and supplemental fuel is required. The composition of the waste stream has to be analyzed in order to determine its heating value and this can take from a few minutes to a quarter hour. In addition, the time delays between the sample point and the analyzer and between the flow control valve position and the flare have to be considered in order to manage the heating value of the gases being flared appropriately. This presentation looks at the modeling and optimization of the flare system. The objectives are to reduce supplemental fuel use while maintaining heating value requirements.