Reducing Fugitive Gas Emissions in Existing Natural Gas Analyzer Installations

How to enhance the efficiency of natural gas instruments while keeping sustainability goals on track 

The broad commitment across industries to minimize fugitive gas emissions has highlighted a growing need to adapt existing natural gas sampling systems for efficiency and environmental sustainability. We propose modifications, specifically to systems for critical parameter measurement such as water and hydrocarbon dew points (Wdp and HCdp). These changes aim to enhance the efficiency of natural gas instrumentation systems while aligning with environmental sustainability goals.

Why focus on reducing fugitive gas emissions?

Fugitive gas emissions – in particular, methane (CH4) – are a significant environmental concern due to the potency of methane as a greenhouse gas. Industries handling natural gas recognize the following key reasons for minimizing these emissions:

1. Climate Change Mitigation: Methane is approximately 25 times more effective than carbon dioxide at trapping heat over a period of 100 years. By reducing methane emissions, industries play a critical role in mitigating climate change.

2. Environmental Responsibility: Reducing emissions demonstrates active commitment to sustainability and environmental stewardship, helping companies comply with regulatory requirements while enhancing their public image.

3. Resource Efficiency: Minimizing fugitive emissions means conserving valuable natural gas, ensuring more of it reaches consumers, and improving resource utilization.

4. Economic Benefits: Implementing energy-efficient practices can lead to cost savings and operational efficiencies while meeting the growing demand for cleaner energy sources.

Suggested modifications to natural gas sampling systems

Many natural gas sampling systems operate with independent measurement channels and continuous flow processes, resulting in gas wastage. Adjusting the flow setup can significantly reduce the amount of natural gas consumed and vented as emissions, without compromising system performance.

The proposed changes involve modifying the flow of gas samples through dew-point sensors to operate in a series, using full-line pressure for water dew-point measurement and cricondentherm conditions for hydrocarbon dew-point measurement. This allows for discontinuous sample flows, reducing the gas consumed during each measurement cycle.

Additionally, downsizing the sample transport lines and optimizing filter systems can maintain gas flow velocity while minimizing the wetted surface area, reducing the volume of gas lost during sampling. For transmission-quality natural gas, replacing continuous-flow filters with manual-drain filters offers another opportunity to limit gas consumption.

What is the rationale for the modifications?

These modifications target the unnecessary continuous flow of gas that typically results in vented emissions. By measuring multiple parameters from a single stream and using smaller tubing, the lost transport time and volume of gas can be minimized, leading to a more efficient sampling process. Maintaining gas velocity through smaller tubing and optimizing the filter system ensures that the analyzer's dynamic response to changes in gas conditions is preserved.

Eliminating the continuous bypass flow from coalescing filters can further reduce emissions for applications where liquid filtration is not critical. However, if condensation is a concern, maintaining some filtration with a bypass may still be necessary.

What impact will this reduction in emissions have?

By implementing these measures, natural gas consumption during sampling can be reduced from typical levels (5 Nl/min) to much lower rates (such as 0.6 Nl/min), significantly reducing fugitive gas emissions. All proposed modifications must be applied together, as omitting any may counteract the overall emission reduction goal.

As the industry works to meet global emissions targets, these practical modifications provide a pathway for reducing environmental impact without compromising operational efficiency.

Did you know?

Fugitive gas emissions, often referred to as ‘invisible leaks,’ can account for a significant portion of greenhouse gases released during natural gas production and transportation. Even in well-maintained systems, tiny leaks from valves, connections, and equipment like natural gas analyzers can add up to considerable emissions over time. By proactively addressing these leaks, operators can reduce environmental impact and increase efficiency.

Advanced monitoring systems, including optical gas imaging and gas analyzers with improved sealing technologies, play a crucial role in detecting and minimizing fugitive emissions. In fact, according to recent studies, implementing regular leak detection and repair (LDAR) programs can cut emissions by as much as 60 % – a win for both the planet and operational costs.