Hydrogen from Methane - and no CO2 emissions
08 April 2013
The Karlsruhe Institute of Technology (KIT) is a major partner in a project that hopes to produce hydrogen from methane without carbon dioxide emissions.
At the Karlsruhe Liquid-metal Laboratory (KALLA), researchers are setting up a novel liquid-metal bubble column reactor, in which methane is decomposed into hydrogen and elemental carbon at high temperature. This is a co-operative project with the Institute for Advanced Sustainability Studies (IASS).
Today (April 8), the initiator of the project and scientific director of IASS, the Nobel Prize laureate Professor Carlo Rubbia, met KIT scientists working at KALLA. Energy production from fossil fuels without greenhouse gas emissions is the goal of this research programme.
Hydrogen represents a promising medium for the storage and transport of energy in the future. However, it is bound in water (H2O) or hydrocarbons, such as petroleum, natural gas or coal. Consequently, it requires separation and inn the course of conventional separation processes, carbon dioxide is emitted. Indeed, today’s worldwide hydrogen production causes about 5% of the global CO2 emissions.
The CO2-free hydrogen production at KIT will be achieved by thermal decomposition of methane in a high-temperature bubble column reactor. “With this project, we have the opportunity to participate in the development of fundamentals for a completely new energy technology,” says KALLA head, Professor Thomas Wetzel.
The liquid-metal bubble column reactor to be built at KALLA over the coming months is a vertical column of about half a metre in height and a few centimetres in diameter. The column is filled with liquid metal that is heated up to 1000°C. Fine methane bubbles enter the column through a porous filling at the bottom, and rise to the surface. “At such high temperatures, the ascending methane bubbles are increasingly decomposed into hydrogen and carbon,” explains Professor Wetzel.
The KIT liquid-metal bubble column reactor is based on previous work by Professor Rubbia and Professor Alberto Abánades from IASS. They studied thermal decomposition of methane in a gas-phase reactor. During this gas-phase reaction, however, carbon deposited on the reactor walls and the gas channels were plugged after a short time; no continuous process was possible.
“In the reactor planned to be built in cooperation with IASS, the shell of the bubbles assumes the role of the wall,” explains Thomas Wetzel. “Only when the bubbles burst at the surface of the liquid metal, is carbon released. The reactor wall is constantly renewed.” A similar approach was described by researchers in Manuela Serban's team at the Argonne National Lab, USA, about ten years ago. Since then, however, this process has not been developed any further.
Following the set-up of the test reactor, KIT scientists will study various parameters influencing the process and the potential hydrogen yield. Work at KIT will also focus on fundamental scientific aspects, for example, on the identification of reaction paths influencing the composition of the product gas flow and on possibilities of removing carbon from the reactor. In parallel, the scientists will select materials for potential future industrial reactors, study filter technology, and develop probes for a continuous process application.