(247aa) Review of Flare Requirements and Challenges in Implementation

Over time the EPA has increased requirements on flares through regulation, consent decrees, and additional new rules.Meeting and maintaining the flare requirements has multiple challenges in order to comply with data processing, recordkeeping, and reporting requirements that can be completed using different combinations of instruments/analyzers and data processing methods (DAHS, DCS, Microsoft Excel, Microsoft Access). Instruments often have QA/QC requirements suggested by the EPA and technical specifications, installation instructions, and operational instructions per the manufacturer. Processing and transforming the raw data collected from the instruments into data for required recordkeeping, data for determining compliance, and data for required reports also has challenges. Flare compliance requires a large volume of raw data for processing, which includes identifying bad data, whether from instrument downtime or other reasons, and following data substitution procedures. The advantages and disadvantages of the different hardware and software combinations for accomplishing the data transformation and meeting the challenges involved are discussed.

In addition, the compliance standards and limits pose their own challenges.In order to comply with the standards and limits, the process control for collaboration between instruments and analyzers becomes important to help the board operator understand and operate the flare. The process control system has to cope with a wide range of operating conditions which creates difficulty in tuning the controller to be effective. For example from zero flow while waste gas is going to a flare gas recovery system to large flows during emergency flaring or for a range of waste gas composition. Furthermore, there are timing issues to contend with, such as instrument lags, valve response times or gain, and travel time for added steam and supplemental gas to reach the flare tip (or the combustion zone). A degrees of freedom analysis and discussion of the control disturbances is presented for troubleshooting the compliance limits and standards.