Hybrid coal technology proposal could double power output

Coal-fired energy producers may gain access to a way to boost efficiency and halve their carbon emissions, thanks to a new hybrid coal gasification system developed by US scientists.

Researchers at the Massachusetts Institute of Technology (MIT) will soon publish a paperwhich describes a combined system for coal gasification, called an indirect carbon fuel cell (ICFC) system.

The study by doctoral student Katherine Ong and Professor Ahmed Ghoniem coupled coal gasification to a solid oxide fuel cell, suggesting this was a promising candidate for high efficiency stationary power with the potential to enable a 50 per cent reduction in carbon dioxide emissions for a given amount of power produced.

The concept was originally described by Ong, then a doctoral student, with Ronald C. Crane in the Journal of Power Sources in 1972.

Coal gasification is already used for the commercial manufacture of hydrogen gas (as well as the controversial technique of Underground Coal Gasification used by Linc Energy in Queensland), while fuel cells produce electricity by causing gas to react electrochemically with oxygen.

Ong explained that the two system both operate at high temperatures, around 800 degrees Celcius, meaning they can exchange heat with minimal energy loss.

This means that the heat generated by the fuel cell can help to sustain the gasification of coal, eliminating the need for a separate heating system, which is usually the conventional combustion of coal.

Without any burning, the system produces less ash and air pollutants that would otherwise be generated by coal combustion, and carbon dioxide is produced in a pure form that is not mixed with air as in a conventional coal power plant, which would make the process of carbon capture far easier than for present technologies.

So far the research has been conducted by simulations rather than lab experiments in order to determine that steam is more efficient for reacting with coal particles in the system, generating two to three times more power output than when carbon dioxide is used.

Ong said the next step will be to build a small-scale pilot plant to measure performance in real-world conditions, which could be achieved in a only a few years due to present availability of technology.

“This system requires no new technologies”, Ong said.

“It’s just a matter of coupling these existing technologies together well.”

Ong admitted the new system would be more expensive than conventional power plants, but capital outlays would be paid off in a short time frame due to superior efficiency and power generation capacity.