February 2, 2022 — Southwest Research Institute has upgraded its test equipment to allow for testing the effects of transporting natural gas and hydrogen blends in the same pipeline. The latest capability will help clients research hydrogen-based solutions to understand if infrastructure for climate-warming greenhouse gases can be transitioned to handle more sustainable resources.
“Hydrogen is an excellent alternative to existing fossil fuels such as natural gas and has the potential to reduce the carbon footprint of the energy sector and achieve a sustainable energy future,” said SwRI Research Engineer Swanand Bhagwat.
Natural gas is primarily composed of methane, but also contains ethane, propane, carbon dioxide and water vapor. Natural gas is considered one of the cleaner burning fossil fuels, but these benefits are cancelled out if a significant portion of the methane leaks out before it is burned. Methane itself is a very potent greenhouse gas, producing significantly more atmospheric warming than carbon dioxide over shorter timescales. Leaks in natural gas pipelines contribute to climate change.
Using hydrogen in place of methane-based natural gas in appliances or carbon dioxide-emitting fuels in combustion engines at first seems like a great solution for decarbonizing our economy and reducing potential climate effects. However, utilizing pure hydrogen in residential applications and power generation comes with many challenges. For example, hydrogen embrittlement can cause leaks and failures in metal parts. Differences in the combustion characteristics of hydrogen mean that a pure hydrogen stream cannot be used in power generation with existing equipment. Also, building new pipelines to transport pure hydrogen is not the most viable solution due to cost and safety concerns.
“To avoid the complexity of dealing with pure hydrogen, the industry is exploring alternative methods to transport hydrogen gas,” Bhagwat said. “Blending small quantities of hydrogen with natural gas is one of the most viable alternatives.”
This blend would require only minor modifications to the operation and maintenance of existing natural gas pipeline networks. Several U.S. companies are already testing the viability of transporting hydrogen blends in their pipelines.
Optical gas imaging (OGI) technologies are widely used to detect methane leaks in natural gas infrastructure. However, OGI systems are blind to hydrogen and may be less reliable for detecting the leaks of hydrogen/natural gas blends.
“To simulate the leaks of blended gas and measure the performance of leak detection systems originally developed for methane/natural gas, we decided to add a mobile flow loop to our inventory of test capabilities,” Bhagwat said.
The flow loop currently operates inside a 60,000-square-foot outdoor complex used to conduct fluid dynamics research and develop and test flow components. The facility complements a suite of test facilities and laboratories dedicated to evaluating instrumentation, equipment and devices for the oil and gas industry. SwRI also uses the facility to test a variety of solutions, including OGI-based machine vision algorithms used in its Smart LEak Detection System (SLED).
“The original test equipment was able to handle just methane or methane-dominated natural gas at one time,” Bhagwat said. “We added a second flow path and additional measurement equipment including a hydrogen-compatible flow meter and needle valves. We also added pressure and temperature transducers and safety devices such as pressure relief valves, check valves, vent lines and a mixing point to allow two gasses — hydrogen and natural gas — to mix before releasing.”
SwRI upgraded the facility’s fittings and piping to stainless steel to make them more compatible with hydrogen and reduce hydrogen embrittlement. Other additions include a purging line for leak inspection as well as a purge box around the facility’s hydrogen flow meter and nitrogen purging lines to remove traces of hydrogen from previous tests.
The updated facility can now simulate leaks of natural gas/hydrogen blends over a range of flow rates consistent with typical field conditions. The test facility can also simulate blended gas leaks for various hydrogen concentrations including 100% methane and 100% hydrogen releases. Custom modifications can also be made to meet clients’ specific needs.
SwRI has a multidisciplinary team dedicated to hydrogen energy research initiatives to deploy decarbonization technologies across a broad spectrum of industries.