Value Extraction and Protein Recycle from Liquid Acid Whey Using Catalytic Electrolysis

Greek (strained) yogurt represents nearly half of the $5B U.S. yogurt industry and has grown at a rate of more than 60 percent per year for the past eight years. For every pound of milk used in the manufacture of Greek yogurt, only one-quarter to one-third ends up in the final product. The remaining waste is liquid acid whey, which contains more than 93 percent water, along with minerals, protein, lactose-based compounds. Acid whey is environmentally hazardous and there are few cash-positive options for disposal or reuse. Waste Hub LLC, under an exclusive sublicense from Catalytic Innovations LLC, has filed a patent application for an electrolysis process that will recover neutral water and separated proteins for recycle while generating fuel-cell electricity and pure carbon dioxide for sale. The process will use the award-winning, heterogenized, iridium-based, molecular oxidation catalyst, developed at Yale University, to selectively oxidize the organics using a fraction of the energy required for state-of-the-art electrolysis processes. Waste Hub will assemble and test a solids-separation and electrolysis unit to refine the Waste Hub process and verify technical and economic viability. We will further develop physics-based predictive models and use them for full-scale system design, economic forecasting, and preparation for a Phase II pilot with a major producer of Greek yogurt. This application is in response to Topic Area 8.4 - Air, Water, and Soils and addresses the cross-cutting USDA priority of Energy Efficiency and Alternative and Renewable Energy from agricultural waste.The hypothesis behind this project is that electrolysis using an iridium-based, heterogenized molecular oxidation catalyst on the anode and a platinum catalyst on the cathode will readily and durably oxidize the organic content of liquid acid whey with relatively low overpotential and will comprise an economically-sound alternative energy technology for processing liquid acid whey. The technical objectives are to confirm this hypothesis, namely:To demonstrate experimentally that acceptable rates of reaction and current density can be achieved using a continuous feed of liquid acid whey with low potential (<2 V).To determine the most cost-effective method of separating suspended solids (protein) and asses the ability to recycle the protein to the processTo collect samples and analyze the flow rates and composition of all outlet streams (H2, O2/CO2, water, solids) and use this information in the development and validation of a process simulation model of the entire Waste Hub system, including the fuel cell and CO2 liquefaction process.To produce designs and economic assessments of a scaled-up pilot and a full-scale system using the validated process model.The key research questions to be addressed in this Phase I project are as follows:What method of solids separation maximizes separation and prevents electrolysis performance degradation while preserving and recovering solids for reuse?What is the effect of solids loading on performance (outlet streams, durability, energy consumption) of the electrolysis system?What is the effect of applied potential on performance (outlet streams, durability, energy consumption) of the electrolysis system?Based on Phase I results, what would be the design, mass balance, energy balance, cost, and financial return of a pilot-scale Waste Hub system to be implemented in Phase II at Stonyfield, and of a complete commercial-scale Waste Hub system at 25,000 gal/day of liquid acid whey?Waste Hub will use samples of liquid acid whey provided by Stonyfield Farm in Londonderry, NH to conduct experiments in 1) suspended solids and protein separation and 2) electrolysis of filtered and non-filtered acid whey in which the anode catalyst, membrane material, and applied voltage will be varied to determine the operating conditions for best performance. Composition of inputs and outputs will be measured in each experiment, including