DMT to supply desulfurization process to California AD facility

By Erin Voegele | September 06, 2017

DMT Clear Gas Solutions recently announced that Calgren Dairy Fuels LLC is going to install DMT’s desulfurization technology, Sulfurex BR. The anaerobic digestion (AD) facility is located adjacent to Calgren Renewable Fuels LLC, a 55 MMgy ethanol plant located in Pixley, California. The AD facility provides heat and power to the ethanol plant.

According to DMT, its project with Calgren supports the production of renewable natural gas for use in vehicles. DMT explained that biogas used to make transportation fuel contains approximately 60-70 percent methane, 30-40 percent carbon dioxide and 3,000 parts per million hydrogen sulfide (H2S). In order to meet California’s air emissions standards, the H2S needs to be removed from the biogas.

DMT said the H2S is removed in a two-step process. The first step is a caustic absorption, followed by a second step of biological regeneration of the caustic liquid. The company said the only byproduct of the discharged slurry is approximately 5 percent elemental sulfur, which can be used as a fertilizer enhancement.

In a statement, DMT said when compared to complete biological desulfurization, its Sulfurex BR technology is unique in that it doesn’t add oxygen to the biogas that is being desulfurized. As a result, the technology makes it possible for a future expansion project at the Calgren facility to inject renewable natural gas (RNG) without worrying about meeting the stringent oxygen requirements of gas utilities in California. In addition, DMT said the plant will meet near future environmental standards and requirements.