Researchers achieve sustainable energy production by improving electrochemical reduction technology

In the vision of sustainable fuel and chemical production in the future, the storage of small amounts of biomass such as sewage, kitchen waste, and sawdust is often overlooked. The reason is that transporting these materials to large-scale centralized biorefineries requires more energy than the energy they produce. However, there is sufficient carbon retention in these materials, which theoretically can provide 25% of the transportation fuel demand in the United States.OlMTextile Testing Instruments, Testing Equipment Manufacturer

A new review led by researchers from the Pacific Northwest National Laboratory (PNNL) provides a solution to capture these unused materials: mini refineries located near waste sources, and electrochemical reduction reactions driven by renewable energy to treat these seemingly difficult to utilize substances.OlMTextile Testing Instruments, Testing Equipment Manufacturer

In a recent paper published in Chemical Review, researchers collected information on the theories, materials, and reactor designs required for efficient processing of industrial substances in mini refineries from over 100 years of chemical theory. Over the past four years, the program has been studying the basic electrochemistry, catalyst design, and reactor design required for functional mini refineries.OlMTextile Testing Instruments, Testing Equipment Manufacturer

The challenge of converting sewage, kitchen waste, and plant waste into fuel lies in the necessary molecular transformation. The first step of this conversion is to decompose biomass at high temperatures to produce crude bio oil. This oil contains molecules such as aldehydes, ketones, esters, acids, and phenols, which contain many oxygen atoms. However, fuel is composed of various hydrocarbon molecules, which contain more hydrogen than oxygen. Adding hydrogen gas to molecules rich in oxygen requires a chemical transformation, known as a reduction reaction. In order to carry out these reactions on bio oil, existing industrial processes bombard bio crude oil with hydrogen gas under high temperature and pressure.OlMTextile Testing Instruments, Testing Equipment Manufacturer

On a large scale, the heat generated during these reaction processes is collected and reused for other refining steps. This maximizes the overall energy efficiency of the process. However, in small-scale situations, this heat will be lost and cannot be reused. This means that other reduction reaction methods are needed for local treatment of small-scale waste.OlMTextile Testing Instruments, Testing Equipment Manufacturer

The well-known electrochemical reduction reaction is a way to achieve the mild conditions required for energy-saving small-scale refineries. In these reactions, electricity and metal catalysts, rather than hydrogen and heat, drive molecular conversion. Other molecules in the mixture can also be removed simultaneously, providing hydrogen atoms during the reaction process.OlMTextile Testing Instruments, Testing Equipment Manufacturer

Compared with thermochemical reduction using hydrogen, electrochemical reduction of specific molecules in bio oil can occur faster and produce fewer by-products without increasing the reaction temperature. This means that fewer purification steps are required in future production processes, thereby improving the energy efficiency of the entire process.OlMTextile Testing Instruments, Testing Equipment Manufacturer

The basic electrochemistry required for electrochemical conversion has been known for hundreds of years. However, most of the work involves laboratory research on model compounds representing molecules from biomass. In this review, researchers outlined the existing information that these reactions still need to be taken out of the laboratory. This information includes research and development of new catalysts capable of handling complex molecular mixtures found in bio oils, as well as electrochemical analysis to develop energy-saving processes.OlMTextile Testing Instruments, Testing Equipment Manufacturer

The quot;Chemical Conversion Programquot; of PNNL provides a rare opportunity to advance this work, as it combines researchers with catalytic expertise with those skilled in electrochemistry. These different perspectives collectively bring knowledge about the basic principles guiding each step of electrocatalytic reactions. Then, researchers can drive existing science towards application based on this broad foundation and match specific reactions with specific production steps.OlMTextile Testing Instruments, Testing Equipment Manufacturer