Hydrogen-gas combustor could cut carbon emissions from gas-fired plants

The Korea Institute of Machinery and Materials (KIMM) has unveiled a hydrogen co-firing combustor for gas turbines used in power generation.

Hydrogen is highly reactive fuel which increases the risk of high temperatures and flashback, which is where the flame propagates upstream against the gas stream.

In order to prevent such risks, KIMM improved a fuel injection method which was then applied to heavy-duty gas turbine. It suppressed instability of the combustion to the same level of the original gas turbine while burning a mixture of 30 per cent hydrogen fuel.

While developed in South Korea, the new combustor needed to be transferred to the German Aerospace Center in Cologne for testing.

There, conditions mimicking the actual operating conditions of the gas turbine were replicated so that its performance could be verified.

When gas turbines use fuel blended with 30 per cent hydrogen, CO2 emissions can be reduced by over 10 per cent. KIMM eventually plans to increase the percentage of hydrogen contents in fuel to over 50 per cent, which would achieve an average 21.4 per cent reduction of CO2.

In addition, the team is a focusing its research efforts with the goal of developing a 100% carbon-free hydrogen combustion technology by 2030.

Commercially available hydrogen is typically demarcated into green hydrogen and blue hydrogen. Green hydrogen is produced by splitting water by electrolysis, while blue hydrogen is produced by splitting natural gas.

While green hydrogen can be a zero-emission fuel when electrolysis is powered by renewables, blue hydrogen can only be described as a net-zero carbon fuel when used in conjunction with carbon capture and storage.

While not specifying the origin of the hydrogen in their experiments, to achieve carbon reductions, the combustor would have to burn green hydrogen. Recent studies have suggested blue hydrogen could have a carbon footprint significantly greater than natural gas, coal and diesel.

KIMM president Sang Jin Park said: “In order to transition to an eco-friendly and carbon-free energy society, it is essential to develop hydrogen fuel conversion technology for medium and large-sized gas turbines and to conduct demonstrations at power plants.”