Skip to Content
Frank Hannemann, 44, of Erlangen, Germany, has refined the process used for CO2-free power generation from coal, with the aim of improving its overall efficiency. Hannemann’s invention could also play an important role in the use of renewable energy sources such as biomass which could be used more efficiently.
Frank Hannemann, 44, from Siemens Power Generation in Erlangen is at least ten years ahead of his time. That, the engineer estimates, is how long it will take until his latest innovation can be realized. Hannemann has refined the process known as the Integrated Gasification Combined Cycle (IGCC) an innovative and environmentally friendly technology for the CO2-free generation of power from fossil fuels. And his efforts have improved the efficiency of the process.
Construction of the first commercial IGCC power plants is now being planned at various locations around the world. The major advantage of this process is that the carbon dioxide produced when fossil fuels are combusted can be removed and stored underground. In the IGCC process, fossil fuels such as brown coal are not combusted but rather gasified. “That’s what makes it such a good method for producing energy from dirty fuels,” Hannemann explains. The basic byproduct of the gasification process is a mixture of hydrogen and carbon monoxide known as “synthesis gas,” along with various other environmentally harmful compounds, including sulfur, chlorine, and alkaline compounds. The synthesis gas must first be purified of these undesirable substances before the carbon monoxide can be oxidized to carbon dioxide and the latter can then be removed. All that remains is pure hydrogen, which combusts without producing any harmful substances. One drawback of this process, however, is that lots of chemical energy is sacrificed in the conversion of carbon monoxide to carbon dioxide, which thus reduces the overall efficiency of the previously used IGCC process where carbon dioxide wasn’t removed. Hannemann’s innovation is designed to remedy this shortcoming.
In Hannemann’s process, separation does not take place before gasification. Before being combusted in a gas turbine, the synthesis gas is mixed with oxygen diluted with carbon dioxide rather than air, as is customary. The resulting exhaust consists of merely steam and carbon dioxide. The steam is condensed to water, and part of the carbon dioxide is fed back into the turbine. The rest is compressed and then separated, as in the conventional IGCC processes. The advantage of Hannemann’s process is that the full energy of the synthesis gas gets used in the gas turbine, boosting the overall efficiency.
What’s more, overall efficiency can be further increased by means of another effect. In conventional IGCC power plants the gasification must take place at a very high temperature in order to prevent formation of methane instead of hydrogen. Unlike carbon dioxide, methane cannot be separated. With Hannemann’s process, the fact that methane combusts to produce carbon dioxide does not pose a problem, since the carbon dioxide is only separated after combustion of the synthesis gas. As a result, the temperature of gasification is significantly lower in Hannemann’s process, so it is more efficient. Hannemann’s innovation could also play an important role in the use of renewable energy sources such as biomass. “The process used to convert biomass into electricity is still very inefficient,” he explains. His process, by contrast, uses biomass much more efficiently and also offers the option of removing the carbon dioxide.
The idea, which Hannemann himself describes as “very radical,” already functions as a simulation. However, as he admits, there is still “a very long way to go” before someone develops a gas turbine that can reliably combust hydrogen along with carbon dioxide and oxygen. Hannemann has been developing new concepts for IGCC power plants for the last ten years. His latest innovation is one of a series of 14 inventions to his credit in the field of IGCC technology. Six of these have been patented. “IGCC power plants utilize an interesting process that goes some way toward meeting our requirements in the future,” he says. For example, their efficiency is high compared to today’s power plants, and they also prevent many harmful emissions, especially carbon dioxide. The RWE utility company is planning to commission its first IGCC power plant in 2014. Hannemann is involved in many of the developments in this field that could well be realized in the coming years. His excellent invention provides us with a glimpse of things to come in the future.