Progress on LDAR Innovation - Report on Research Under CRADA #914-16
Citation:
Thoma, E., H. Lane, M. MacDonald, C. Smith, B. Kelley, M. Clausewitz, D. Cartwright, K. Anderson, W. Peng, L. Lin, A. Chernyshov, M. Xu, AND D. Massner. Progress on LDAR Innovation - Report on Research Under CRADA #914-16. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-20/422, 2021.
Impact/Purpose:
Energy production operations, refineries, chemical plants, and other industries and waste facilities can emit air pollutants and odorous compounds from fugitive leaks, process malfunctions, and area sources that are hard to detect and manage. From the shared perspective of industries, regulators, and communities, improved understanding of these stochastic industrial sources (SIS) can yield many benefits such as safer working environments, cost savings through reduced product loss, lower airshed impacts, and improved community relations. The emergence of lower-cost sensors and inverse modeling approaches is enabling new cost-effective ways to detect and analyze SIS emissions. Under its next generation emissions measurement (NGEM) program, EPA ORD is working with a range of partners to develop and test NGEM tools that can assist facilities in detection and management of SIS sources. As described in the below abstract, the following product contributes to the general advancement and communication of NGEM concepts.
Description:
In the U.S., fugitive emissions (leaks) of VOC and HAPs from process components have traditionally been managed using scheduled manual inspection of individual components with U.S. EPA Method 21 (M21) as part of facility LDAR programs. Although sensitive and flexible, M21 is resource intensive, requiring equipment-laden operators to physically inspect and document a vast number of components, searching for the approximate 1-2% that are leaking. Due to the implementation burden of M21-based LDAR, it is conducted infrequently (quarterly to annually), creating the potential for emissions to go undetected for extended periods of time. Additionally, M21 LDAR programs are not designed to comprehensively monitor all potential fugitive SIS emission points in a facility. This likely increases the risk that unintended emissions can go undiscovered indefinitely, or until worsening to the point of human detection by audio-visual-olfactory procedures or safety monitors in more serious cases. In 2017 EPA ORD initiated a CRADA with Flint Hills Resources (FHR), a refinery operator, and Molex, a connector and sensor company. The “Leak Detection and Repair (LDAR) Innovation CRADA” (#914-16) has a goal to develop, test, and deploy new sensor network-based solutions for fugitive SIS detection that will enable the emissions management strategies of the future. The LDAR Innovation CRADA, has successfully developed and tested a first-of-its-kind refinery leak detection sensor network (LDSN) that operates with specialized facility procedures defined in a detection response framework (DRF) to produce an integrated emission monitoring and documentation system. The automated and continuous LDSN system, along with optimized DRF protocols, enables leaks to be detected and repaired faster and more efficiently than with quarterly or annually executed M21. This report reviews the strengths and weaknesses of sensor-based leak detection approaches and describes the development and testing process that culminated in long-term trials in working FHR refinery process units. The real-time analytics of Molex’s mSyte™ sensor information system helped the facility repair team discover and assess a range of leak sizes, many with emission levels well below that routinely detectable with other next-gen survey approaches, such as optical gas imaging. In addition to leaks associated with routinely monitored components, unexpected emission sources not detectable by other approaches were also found, illustrating the value of the 24/7 area-monitoring concept. Multiyear simulated emission modeling based on real-world leak detection data showed that the new sensor-based approach can provide equivalent or better emissions control to M21 for cost-realizable sensor network node densities. In addition to development, testing, and emission modeling results this report describes quality assurance advantages of the developed approach and outlines areas for potential future research.