New process cracks methane to produce hydrogen without emitting carbon dioxide

Natural gas accounts for more than 28% of the U.S. energy consumption. The main component of natural gas is methane, which is a widely used fossil fuel, and it is the main cause of the rise in global carbon dioxide levels and the resulting climate change. To solve this problem, researchers at the Institute for Advanced Sustainable Development (IASS) and Karlsruhe Institute of Technology (KIT) have developed a method for extracting the energy part of methane, ie hydrogen, which does not produce carbon dioxide. This process is called "methane cracking." Methane molecules are cracked into hydrogen and carbon at temperatures above 750°C without harmful emissions. The concept of methane cracking has existed for several decades, but the conversion rate is low, and the equipment will cause carbon blockage.

The researchers used a new 1.2-meter-high (4-foot) reactor design based on liquid metal technology in the cracking process, made of quartz and stainless steel. Fine methane bubbles are injected into the molten tin column. As they rise to the surface, carbon is separated and deposited as a powder at the top of the reactor, avoiding the formation of particulate carbon powder to clog the equipment, while the reactor is designed to be more corrosion resistant.

Tests have shown that at 1200°C, the reactor produces a hydrogen conversion of 78% and operates continuously for two weeks, so the final reactor is expected to reach an industrial scale, which will be powered by the generated hydrogen. Studies have shown that methane cracking is equivalent to the electrolysis of water, with carbon dioxide emissions per unit of hydrogen, and is more than 50% lower than steam methane reforming technology. Preliminary calculations show that the cost of this technology per kilogram of hydrogen is 2-3.5 US dollars (currently the price of natural gas in Germany). The next phase of this study will focus on optimizing the reactor design and gradually extending it to increase hydrogen flow.