Science Centres: Energy

Pure hydrogen stream on track

Scientists at CRL Energy are well on their way to producing high purity hydrogen from New Zealand lignite. This hydrogen would be suitable for fuel cells to generate electricity – for distributed and large-scale applications, and for running vehicles.

Technology for New Zealand conditions

Pure hydrogen stream production

At its most basic, the process is to feed coal into a gasifier to produce ‘syngas’ which is primarily hydrogen, carbon dioxide, and carbon monoxide.

The syngas is then cleaned to produce a pure hydrogen stream [see diagram].

Over the past four years, CRL Energy has built and commissioned a ‘fluidised bed’ gasifier and associated computer control system. The pilot plant is large enough to power about 20 houses. We can now generate a reliable and consistent stream of syngas of known quality from New Zealand lignite.

Compared to other advanced gasification technologies, fluidised bed gasification is relatively simple in design and construction, suitable for distributed generation and industrial scale facilities. New Zealand lignites are extremely well suited to this technology.

Breakthroughs in clean-up

Our research partner, IRL, is developing an alkaline fuel cell package which requires extremely high purity hydrogen.

We are making substantial progress in removing impurities and maximising the amount of hydrogen we produce.

• Particulates & condensables: A combination of a high efficiency cyclone and a Venturi scrubber (both well-established technologies) is working well.
• Sulphur: We have designed, built, and tested a new desulphurising system, and can now totally remove sulphur gases from the syngas (a major milestone).
• ‘Water gas shift reaction’: Syngas contains carbon monoxide (CO). This can be converted into more hydrogen and carbon dioxide (CO2) by running the syngas and steam over a catalyst bed (known as the ‘water gas shift reaction’). Our system is built and testing is in progress.
• Creating a pure hydrogen stream: To separate the hydrogen from carbon dioxide, CRL Energy is working with the Energy research Centre of the Netherlands (ECN) using new ceramic ‘membranes’ coated with the rare metal palladium. Hydrogen can pass through the membrane but CO2 cannot. We will also incorporate more proven, but less efficient, CO2 separation technology.

The IRL/CRL Energy hydrogen research programme is funded by the Foundation for Research, Science & Technology. It is overseen by an industry Governance Panel involving high-level representatives of Solid Energy, BP New Zealand, and Meridian Energy, and runs until 2008.