Hydrogen sulfide (H2S) is produced from the decomposition of plant and animal matter, with around 90 percent of H2S emissions being naturally sourced. Hot springs and volcanoes also release substantial amounts of H2S. Natural gas containing significant levels of sulfur is termed “sour” and requires treatment before it can be distributed to residential, commercial, and industrial customers. Untreated H₂S is typically flared for safety reasons and to convert it into less dangerous pollutants, but the practice still generates emissions.
How Sour is Sour?
Natural gas produced from oil and gas wells is approximately 70-90 percent methane and contains up to 20 percent of heavier hydrocarbons, including ethane, butane, and propane. Gas produced from an oil or gas well typically contains other contaminants, too, including water vapor, sand, oxygen, carbon dioxide, nitrogen, and in many cases, hydrogen sulfide.
There is no one set definition of what constitutes “sour” gas, because concentration levels can vary widely from area to area. The Texas Railroad Commission, however, defines sour gas as having an H2S concentration of 100 ppm or more as noted in Statewide Rule 36, which provides provides sour gas operating requirements to safeguard worker and community safety (source: Statewide Rule 36).
READ MORE: What Makes an H2S Treating Solution “Green”?
How Does Sour Gas Cause Emissions?
Sour gas presents a threat to both human health and infrastructure. Sour gas production must be produced and transported using equipment specialized for “sour service,” treated and coated to withstand the corrosive effects of sour gas and is subject to stringent maintenance regimes. In some cases, very high levels of H2S contamination (10,000 ppm or greater) may require onsite gas treatment to reduce H2S to lower levels suitable for sour service handling. Otherwise, these assets cannot be produced.
Traditionally, sour gas has been flared or combusted to transform the contaminated gas into less harmful substances. However, flaring sour gas produces other pollutants such as sulfur dioxide (SO₂), which contributes to acid rain; volatile organic compounds (VOCs); and nitrogen oxides (NOx), which can react with particulates and sunlight to form ozone. Additionally, incomplete combustion may release raw H2S into the atmosphere.
Restrictions on flaring are increasingly stringent due to both regulatory mandates and voluntary industry efforts. For instance, the North Dakota Industrial Commission, which regulates the Oil and Gas industry in that state, requires operators to capture 90% of produced gas and reduce flaring. In New Mexico, the Oil Conservation Commission requires upstream and midstream operators to reduce routine natural gas flaring and venting by 98% by 2026.
The U.S. Environmental Protection Agency has also recently revised its emissions regulations in NSPS OOOOb and EG OOOOc, aiming to phase out all non-emergency flaring in the future.
Many operators have committed to voluntary emissions reduction programs. The Oil and Gas Methane Partnership 2.0 (OGMP 2.0) has emerged as an influential industry group who members include many large operators with producing assets in the United States and worldwide. OGMP 2.0 has developed a framework for estimating and reporting emissions from oil and gas operations, including emissions from tank venting, purging, and flaring.
Gas Sweetening
The process of treating sour natural gas to remove H2S so it can be sold instead of flared, generating emissions, is called “sweetening.”
In our article, Gas Sweetening, Sour Gas Treatment Strategies by Volume, we identified the three primary categories of traditional gas treating methods for removing H₂S from produced gas, including (a) scavengers and adsorbents, (b) catalytic reactions, and (c) mechanical destruction or injection. These methods, however, have numerous downsides, including:
- Create negative downstream processing effects.
- Require the use of chemicals that can be expensive and present a safety risk.
- Require the disposal of contaminated media, creating environmental and safety risks.
- Operational complexity, requiring frequent oversight on location and problem solving.
Valkyries Reduce Oil & Gas Emissions Using Next Generation Liquid Redox for H2S Treating
The Liquid Redox (Reduction-Oxidation) process converts H₂S into elemental sulfur and water vapor byproducts using chemistry (Reduction) that can be regenerated and used again with exposure to air (Oxidation).
Using a Next Generation Liquid Redox process, sour gas is directed into a treating vessel containing specialized chemistry and then exits the system sweet (without H₂S) into a gas sales line. The elemental sulfur byproduct is filtered out of the liquid, and the chemistry is then regenerated with exposure to oxygen. The regenerated chemistry is then recirculated back into the treating vessel to perform the reaction again. The regenerative nature of the chemistry reduces media changes, disposal costs and reduces chemical handling requirements on the well site.
The VALKYRIE® H₂S treating solution from Streamline Innovations utilizes relatively recent technological advances in automation control to create the “Next Generation Liquid Redox” system. The VALKYRIE system utilizes TALON® chemistry, our non-toxic, biodegradable Redox chemistry.
VALKYRIE technology is a true green solution, by reducing the flaring of sour gas and related emissions at oil and gas production sites by converting H₂S into harmless byproducts, including elemental sulfur certified for use in food production.
READ MORE: Streamline’s Sulfur from H2S Receives Listing as an input for Organic Food Production
The Streamline VALKYRIE H₂S removal system is the next generation of Liquid Redox (Reduction-Oxidation) to cost-efficiently help oil and gas operators unlock the value of sour gas resources and reduce emissions from oil and gas operations.
VALKYRIE Technology Applications
VALKYRIE H₂S treating units for sour gas sweetening and reducing emissions from oil and gas operations are suitable for a variety of oil and gas applications, including:
- De-bottlenecking sour gas takeaway constraints with onsite H₂S treating.
- Fuel gas conditioning for Gas Lift to minimize sweet gas buyback.
- Tail Gas treating.
VALKYRIE gas treating units have been operating reliably for oil and gas producers in the Permian Basin and elsewhere, including Chevron Corporation, Franklin Mountain Energy, and Taprock Energy, among others.
Benefits of the VALKRYIE gas treating system:
- A green solution that converts H₂S into benign substances including water and elemental sulfur.
- Universal application for biogas, landfill gas and oil and gas production.
- Widest operating envelope of any H₂S gas treating method extending across the full spectrum of pressures, flow rates and H₂S concentrations.
- Treating to established specifications for sales pipelines, gas lift and fuel gas.
- Flexibility of placement along the production stream whether at the anaerobic digester, at a landfill, wellhead, refinery, in a direct or tail gas treating configuration.
- Meets the most stringent outlet specifications.
In our 2023 Sustainability Scorecard, the VALKYRIE fleet helped operators avoid 39.7 million pounds of SO2 emissions, among other benefits.
READ MORE: Streamline Innovations 2023 Sustainability Scorecard
Contact us today to learn how VALKYRIE H₂S treating technology can help you reduce emissions from your oil and gas production operations.
About Streamline Innovations
Streamline Innovation’s vision is Reducing Emissions Through Technology. We help heavy industry around the world achieve environmental performance objectives, improve sustainability, and transition to a sustainable, low-carbon economy. Streamline Innovations Leads TIME’s List of America’s Top GreenTech Companies of 2024.
H2S is present in almost every industrial process in the world. Our technology can be applied across industries, delivering a sustainable solution that eliminates H2S, the leading cause of acid rain, a deadly greenhouse gas dangerous for work and living environments.
Streamline believes that achieving the E (“Environmental”) in ESG requires data. Creating intelligent systems that operate effectively and efficiently without human intervention is critical to reducing emissions that harm the environment. We integrate advanced data collection, process control, and analytics in our technologies to provide a total solution for customers.
We serve organizations in multiple sectors, including Energy/Oil & Gas, Biogas, Landfill Gas & Renewable Fuels, Municipal Wastewater and Industrial Air & Water.
