Gas flares are an important safety and emission control device used by the petrochemical and chemical industries to dispose of large amounts of flammable hydrocarbon gases produced in various manufacturing and industrial processes. Characterizing flare performance is based on measuring flare emissions (i.e., CO, CO2, CH4, unburnt hydrocarbons, and soot). Earlier work has focused on characterizing elevated flares using extractive sampling techniques developed for standard stack sampling (e.g., CMA 1983 and TCEQ 2010). More recent work has extended this to use various ground based optical techniques including Open-Path Fourier Transform Infra-Red Spectroscopy (OPFTIR), the SKY-LOSA technique for Black Carbon (BC) emissions, and passive FTIR (PFTIR). Tests have examined the performance of non-assisted and assisted flares with samples collected from a single region above the flare combustion zone. These measurements taken from a temporally and spatially varying plume represent an averaged data point. Until now, no techniques have been used to quantify real-time flare performance of a single point elevated flare, nor a multi-tip ground flare, due to sampling limitations (see Figure 1).
Elevated Analytics, Inc. has developed a new unmanned aircraft system (UAS) for flare emissions monitoring using spectroscopy. This technology was recently demonstrated at the Zeeco test facility in Broken Arrow, OK (see Figure 2).
Elevated Analytics is currently deploying this breakthrough monitoring system to measure real time emissions in plumes originating from industrial flare systems. The UAS monitoring system can measure CO, CO2, CH4, H2O, SO2, NO2, VOCs; as well as local gas temperature, thermal radiation flux, and soot particulate emissions. The complete system includes several technologies: high precision GPS, onboard signal processing, transmission equipment, and batteries – all in a compact, lightweight package, fit into a commercially available UAS.
The new UAS mounted flare emissions monitoring system provides several improvements over previous land-based monitoring systems:
Real time flare emissions data via sample rates, as fast as once per second
Samples are taken throughout the flare plume to accurately quantify flare performance
Rapid feedback to plant operations for better plant control, and thus optimize operations
Ability to monitor multiple locations around a flare simultaneously in real time
Ability to improve flare design – optimize flare performance at full operating rates under adverse wind conditions
Use multiple UAS mounted systems, deployed together, in order to monitor real time performance data of multi-tip ground flares
This break-through technology represents a first for full-scale flare emissions data monitoring that will allow plants to optimize performance while ensuring environmental compliance. The technology also allows environmental agencies an economical way to easily monitor flare performance during upset conditions and accurately apply potential environmental compliance penalties. Eventually, this technology allows individuals the ability to monitor local air quality and improve the quality of life.