Optical Gas Imaging (OGI): Maximizing Emission Reduction for Freeport LNG
To date, Freeport LNG on the Texas Gulf Coast is the largest privately funded construction project in the United States.
In 2017, Montrose began its second major LDAR entry into the LNG industry with Freeport LNG. To date, Freeport LNG on the Texas Gulf Coast is the largest privately funded construction project in the United States. It consists of a pretreatment plant and three liquefaction trains, with a fourth train to be added in the future. The liquefaction plant and pretreatment plant are not co-located and are permitted as separate facilities for new source review (NSR) purposes under Texas Commission on Environmental Quality (TCEQ) Permit Numbers 100114 and 104840, respectively. Both facilities are subject to LDAR requirements in accordance with TCEQ’s 28MID LDAR program. The plants began operations in early 2019.
Taking a Thorough Assessment of Potential Emission Rates
The maximum allowable emission rate tables (MAERT) in the TCEQ permits state a limit in tones of volatile organic compounds (VOC) from leaking components for the liquefaction and pretreatment plants. These limits consider the control efficiencies associated with a TCEQ 28 MID LDAR program. FreeportLNG’s limit was initially calculated based on an estimated component count of 10,000. Montrose was awarded the LDAR program development and implementation program in 2018. We quickly ascertained that the 10,000 count was a significant underestimation and prepared for a much larger count.
The LDAR component inventory included a thorough analysis of the Heat and Material Balances and P&IDs to identify streams that would meet the regulatory threshold. The final inventory was 76,000+ components. However, in order to stay under the initial MAERT limit and provide an enhanced LDAR system to FreeportLNG we recommended the use of the AWP.
Achieving Significant Emission Reduction with Alternative Work Practice (AWP)
Although Montrose was brought on to the project after the permit was completed, we helped Freeport LNG develop a strategy that maximized the emission reduction of the LDAR program. We implemented an Optical Gas Imaging (OGI) program pursuant to the EPA Alternative Work Practice (AWP) in 40 CFR Part 60, Subpart A,
§60.18, incorporated into TCEQ regulations at 30 TAC §115.358. We met directly with TCEQ staff to explain the benefits of an AWP pro- gram and outlined how it would meet or exceed the permit requirements and provide a significant total emission reduction. This resulted in the permit being modified, via a permit alteration, to include the AWP.
The benefits of the program implemented include:
- A significant reduction of total emission rates due to faster identification and repair of leaks when surveys are conducted on a more frequent basis (bi-monthly versus quarterly)
- Identification of ongoing leaks from unmonitored equipment (insulated or even non-regulated)
- Identification of potentially hazardous conditions associated with leaks from process equipment, the monitoring of which can be incorporated into Freeport’s safety program
- Identification of exact leak source, preventing leak and repair errors (i.e., eliminates “ghost leaks”)
- The ability to monitor ~2,000 components per hour (versus ~60 components per hour using Method 21)
Improving Maintenance Using OGI
Additionally, the implemented program enables Freeport LNG to confirm leaks that were previously identified using Method 21. OGI proves especially useful in areas of tight component configurations where Method 21 may have difficulty identifying—or, in some cases, can even misidentify—the source of a leak.
With OGI, Freeport LNG now detects leaks from difficult-to-monitor components, unsafe-to-monitor components, and insulated components. These components are monitored on a more frequent basis than if Method 21 were used, allowing Freeport LNG to reduce emissions from its facilities, improve site safety, and provide additional cost savings through the reduction of lost product.
Though OGI has proven more effective in leak detection than Method 21, Freeport LNG will keep Method 21-related elements of its current LDAR Monitoring Plan intact, such as using Method 21 devices to calculate emissions based on leak concentration.
Three full-time Montrose employees manage Freeport LNG’s program, and they are responsible for all aspects of monitoring, quality assurance, and quality control. This includes the annual M21 requirements, facility camera scans (performed every two months), repair confirmations, and complicated emission calculations.
The hands-on approach taken by Montrose has allowed Freeport LNG to meet all of its compliance goals with ease. Freeport LNG has provided extremely positive feedback on the performance of our staff, specifically commenting on their professionalism and efficiency. The Freeport LNG stakeholders have also informed us
that our LDAR Program Management software TARGET ONLINE has become seamlessly integrated into their workflow to ensure rapid leak repair and trusted compliance reporting.