How Byproducts of the Biogas Purification Process Create a Muddied Field
Not all RNG is created equal. “Created” being the critical word.
Renewable Natural Gas, (RNG or biomethane) is generated through a sometimes lengthy and complicated biogas upgrading process. Biogas, in its raw form, contains contaminants that can be harmful to the environment and have negative effects on pipelines, storage facilities and other infrastructure. As a result, biogas, whether it is produced from an agricultural operation or a landfill, must be purified of contaminants including H2S, oxygen, CO2, N2, siloxanes and other elements before it can be sold commercially as highly valuable “Green Power” RNG.
Although the green concept is rooted in decarbonizing energy systems by reducing Greenhouse Gas emissions, the true “greenness” of an energy operation is called into question if it generates byproducts harmful to the environment and/or simply replaces one type of emissions with another.
With this context in mind, not all H2S treatment solutions are created equal. For an RNG operation to live up to its sustainability promise, the issue of byproduct generation, especially in H2S treatment, must be addressed to ensure the holistic sustainability of energy production.
This article covers various methods for treating H2S for upgrading biogas and landfill gas to RNG and the benefits of using a green H2S solution.
The H2S Problem
Hydrogen sulfide is a common impurity in various energy sources, including fossil fuels, biogas and Landfill Gas. Treating sour gas (natural gas containing H2S) in oil and gas operations has been a priority for many decades for protecting infrastructure and ensuring operational safety (H2S presents a serious health threat to workers). H2S presents a similar challenge in upgrading biogas and landfill gas to RNG, so it can be injected into commercial pipelines for sale.
Solutions for Dealing with H2S
Various methods exist to remove H2S from gas streams, ranging from traditional techniques to innovative green solutions:
Traditional H2S Treating Methods
In our article, Gas Treating Solutions for Renewable Natural Gas, we covered the primary categories of gas treating to remove H2S from landfill gas, biogas and geologic sources. Conventional H2S treatment methods, including scavengers, adsorbents and catalytic reactions are plagued with a variety of downsides:
- 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 system maintenance
Solid Media: Activated carbon and Iron Sponge are commonly used for H2S treating in RNG operations. These materials absorb H2S, effectively removing it from the gas stream. However, they have limitations such as saturation issues, resulting in downtime for changing out spent media and the cost of disposal. Because these methods, like Triazine, create spent media cannot be recycled and must be disposed of in a landfill or other facility, they do not deserve a “green” rating.
Green H2S Treating Methods
Biologics and Next Generation Liquid Redox are significantly more green than traditional methods of treating H2S, primarily because they do not create negative byproducts.
Biological Systems: Biological processes are green because they utilize microorganisms to convert H2S into non-harmful compounds. While biological H2S treating methods are eco-friendly because most commercially available biologic H2S treating processes extract elemental sulfur from biogas, they typically require long start-up times to allow a critical mass of microorganisms to grow and are highly sensitive to changes in gas flow, temperatures, and H2S Concentrations, which can result in unplanned downtime and lengthy restarts. In addition, biologic systems typically require additional equipment to maintain a steady state, increasing the cost of these systems and adding operational complexity.
Next Generation Liquid Redox (VALKYRIE™): The next generation of liquid redox solutions, such as VALKYRIE Biogas-to-RNG technology, provide biogas and Landfill Gas operators a H2S purification solution that is not only green, but operationally robust. This innovative technology has proven itself in the fossil fuel industry and offers RNG operators an efficient and effective means of eliminating H2S from biogas and Landfill Gas without harmful byproducts. The process involves using non-toxic and environmentally friendly chemicals to oxidize H2S into Simple Elemental Sulfur™, a valuable byproduct certified by OMRI for use in organic food production. VALKYRIE technology is energy efficient, produces no harmful emissions, facilitates quick startups, and resistant to variability in gas flow rates and temperature.
These green H2S treating methods help promote and facilitate the longer-range vision of a Circular Economy where the outputs of one industrial process become the inputs of another, helping us realize a Green Future sooner than imagined. By extracting elemental sulfur from H2S, it can be returned to the soil and used for organic food production.
Learn more about our vision for A Green Future.
Benefits of VALKYRIE H2S for Biogas-to-RNG Upgrading
The adoption of the VALKYRIE ECO or VALKYRIE ECO FLEX H2S treating solutions provide biogas and Landfill Gas producers a robust, efficient and green H2S removal solution for upgrading their gas to RNG.
Benefits of VALKYRIE technology include:
- Recyclability and reusability of byproducts like Simple Elemental Sulfur™ enhances resource utilization and create a true green solution with no harmful byproducts.
- Treats H2S down to non-detect levels from a single skid.
- Reliable and robust – insensitive to variability in biogas H2S concentrations and temperatures.
- No additional conditioning equipment is needed.
- Use of non-toxic and eco-friendly chemicals ensures minimal environmental impact.
- Utilization of renewable or low-impact resources aligns with sustainable practices.
- Faster startup and higher uptime when compared to biologic treating alternatives.
- Energy efficiency is maintained, reducing operational costs and resource consumption.
- Reduced waste generation and the generation of harmful byproducts contribute to cleaner operations.
- Cost-effectiveness is achieved through efficient and optimized processes.
Learn more about Streamline’s VALKRYIE ECO and ECO FLEX Biogas-to-RNG Upgrading Technology.
Summary
The transition to a decarbonized global energy system is accelerating and RNG has an essential role to play, but a energy source is only as green as the byproducts it generates. Addressing the H2S problem in biogas and Landfill Gas is a significant step towards producing cleaner, upgraded RNG suitable for commercial pipelines. Traditional methods have significant limitations, but VALKYRIE technology offers RNG operators a reliable, robust, efficient, clean and holistic option aligned with green energy goals.
About Streamline Innovations
Streamline Innovations’ vision is Eliminating 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’s environmentally forward H2S treating solutions help our customers achieve the “E” in ESG. H2S is present in many industrial processes throughout the world, and our technology can be applied across industries, delivering a sustainable solution that eliminates H2S, a leading cause of human inhalation accidents, corrosion and SO2 emissions, a primary cause of acid rain.
We also believe that achieving climate-improving directives requires data. Creating intelligent systems that operate effectively and efficiently without human intervention is critical to measuring and reducing emissions that harm the environment. We integrate advanced process control, data collection 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.
Contacts
General Inquiries:
Randy Rohlfs
Chief Commercial Officer
Randy.Rohlfs@StreamlineInnovations.com
Sales Inquiries:
Jacob Pratt
SVP – Sales
Jacob.Pratt@StreamlineInnovations.com
