Powering Sustainability: Agricultural Biogas Transformed to Renewable Natural Gas with GraniteFuel Engineering
One of the largest dairy farms in the United States and a producer of milk based in Indiana, renowned for its commitment to sustainability and innovation, sought to revolutionize its waste-to-energy practices. Collaborating with GraniteFuel Engineering, a prominent biogas equipment supplier, operators embarked on a transformative journey to convert biogas derived from manure and dairy waste into pipeline-quality Renewable Natural Gas (RNG).
Biogas upgrading Challenges
Dairy farm operators encountered several challenges on its path to harnessing the potential of biogas for RNG production. The foremost hurdle was managing the variable incoming flow of unpressurized biogas, which needed to be upgraded to pipeline-quality standards for seamless injection into the local grid. The complex nature of agricultural digester-derived biogas necessitated precise treatment to meet stringent pipeline specifications and ensure compliance with industry regulations. Additionally, exceptionally high levels of Hydrogen Sulfide (H2S) posed a unique challenge, demanding innovative strategies to enhance operational efficiency and extend media lifespan.
Biogas Blending Challenges
Navigating the intricacies of biogas blending presented a distinct challenge as GraniteFuel was tasked with combing the product gas from another sources before injection into the grid. This required the GraniteFuel equipment to exceed the standard pipeline specifications, compelling the project to achieve a methane content surpassing 98% in the final product gas. To overcome this challenge, GraniteFuel Engineering executed meticulous adjustments to their upgrading system, fine-tuning its components to ensure the rigorous methane purity requirement was met. This intricate calibration and optimization underscore the dedication to innovation and precision that GraniteFuel brought to the project, successfully enabling seamless biogas blending and injection while maintaining the highest standards of quality and compliance.
GraniteFuel’s Comprehensive Solution:
GraniteFuel Engineering undertook the task of designing, engineering, and building a comprehensive RNG plant for the agricultural biogas digester, addressing every intricate detail of the biogas upgrading process. The project was custom-tailored to handle constantly varying gas flows ranging from 400 to 770 standard cubic feet per minute (scfm) of raw bioags. Key components of the supplied system included H2S removal, gas compression, biogas dehydration, biogas membrane separation, and sales gas compression. The proprietary systems designed by GraniteFuel Engineering exhibited versatility and precision, ensuring the successful conversion of raw biogas into high-quality RNG.
Challenges of H2S Hydrogen Sulfide
Hydrogen Sulfide (H2S) is a colorless, highly toxic gas with a distinctive rotten egg odor. In biogas, H2S is typically produced during the decomposition of organic matter in anaerobic conditions, such as in agricultural digesters, wastewater treatment plants, and landfills. Its presence in biogas poses several challenges. Firstly, H2S is corrosive and can cause damage to gas upgrading equipment, power generation equipment, and infrastructure like gas pipelines. Moreover, when biogas is upgraded to Renewable Natural Gas (RNG) for use as a clean energy source, the high H2S content can contaminate the end product gas, rendering it unsuitable for injection into gas pipelines or combustion in engines due to potential equipment damage and adverse environmental effects. Therefore, efficient removal of H2S from biogas is essential to ensure the safety of the upgrading process, protect equipment, and produce a high-quality RNG suitable for various applications without compromising performance, compliance, or environmental standards.
Innovative Proprietary Systems:
One of the critical challenges faced by the dairy farm operators was the exceptionally high H2S levels in the biogas, reaching around 3000 parts per million (ppm). In response, GraniteFuel Engineering introduced an innovative Oxygen (O2) injection system, a first-of-its-kind approach within their projects. By injecting O2 into the H2S removal system, the adsorbed H2S was displaced and converted into elemental sulfur, thus extending media life. This pioneering solution not only optimized operational costs but also improved the overall efficiency of the H2S removal process.
Furthermore, GraniteFuel Engineering fine-tuned the upgrading system to exceed the demanding specifications required for natural gas pipeline injection. Achieving a greater than 98% methane content in the product gas was critical, given the blending of gas from multiple sources prior to injection into the grid. Through meticulous tweaking and system optimization, GraniteFuel’s expert team ensured that the Renewable Natural Gas met or surpassed the rigorous pipeline-quality standards, resulting in a reliable and compliant energy source.
Sustainable Natural Biogas Gas (RNG)
The collaboration between Fair Oaks Farms and GraniteFuel Engineering exemplifies the potential of innovative biogas conditioning solutions in driving sustainability and energy independence. The successful conversion of agricultural waste into pipeline-quality Renewable Natural Gas not only addresses environmental concerns but also contributes to the reduction of greenhouse gas emissions and reliance on fossil fuels. Through cutting-edge proprietary systems, including the revolutionary O2 injection approach, GraniteFuel Engineering paved the way for the dairy farm to harness the power of biogas and propel the dairy industry towards a greener, more sustainable future. This project underscores the critical role of collaboration between industry pioneers in shaping a world powered by renewable energy.
