Development of a Real-Time Flare Combustion Efficiency MonitorEPA Contract Number: EPD15012
Title: Development of a Real-Time Flare Combustion Efficiency Monitor
Investigators: Zeng, Yousheng
Small Business: Providence Photonics, LLC
EPA Contact: Richards, April
Project Period: November 1, 2014 through October 31, 2016 (Extended to October 31, 2017)
Project Amount: $299,877
RFA: Small Business Innovation Research (SBIR) - Phase II (2014) Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Air
There are approximately 7,000 flares in operation at industrial facilities across the United States. Flares are one of the largest volatile organic compounds (VOC) and air toxics emission sources. Based on a special emission inventory required by the Texas Commission on Environmental Quality in 2007, highly reactive VOC emissions from 28 flares located in Harris County, Texas were 1469.5 tons in a year, which accounts for 60 percent of emissions from these facilities. Currently, there are no practical methods available to measure emission rate or control efficiency of flares. For air emissions inventories, flares are assumed to have an efficiency of 98 percent when their operations meet conditions codified in federal regulations (40 CFR §60.18). Many studies have shown that this 98 percent efficiency assumption may not be valid, even when flares meet these regulatory requirements. If actual flare efficiency varies, it can cause large errors in emission inventories, affecting air quality planning, compliance, health impact assessments, and associated decisionmaking.
The proposed Flare Efficiency Monitoring System (FEMS) uses a 9-band “staring” multi-spectral infrared (IR) imager to determine relative concentrations of CO2, CO, and hydrocarbons (HC) in the flare plume, then calculate flare combustion efficiency (CE) in real-time. The successful Phase I proof of concept demonstrated that this method is technically feasible. The experiments performed during Phase I established a very strong correlation (r2=0.9852) between known CE values and CE values measured with the FEMS technology. In addition to calculating flare CE in real-time, Phase I work also demonstrated that the FEMS technology can calculate CE and temperature at the pixel level, thereby producing a complete CE and temperature map of the flare plume. This feature can be valuable to flare operators and combustion engineers for analysis of spatial variability and temporal dynamics in flare combustion.
In Phase II, Providence will produce a working prototype of the FEMS and a calibration device. The prototype will be field tested on a large-scale industrial flare alongside other (less practical) methods of measuring flare CE (e.g., extractive method, PFTIR). The FEMS prototype will be capable of measuring flare CE at the pixel level and performing spatial and temporal averaging to provide an overall representation of flare CE in real-time. The real-time flare CE can then be supplied to a flare operator or control device through an industrial interface, providing a method to optimize flare operation and reduce overall emissions from flaring activities.