Reducing energy consumption in sodium chlorate production by 10–20%
VTT has developed a pilot-scale power plant based on fuel cells that utilises
by-product hydrogen from the process industry. The power plant has been in
operation at Kemira Chemicals Oy’s site in Finland since January 2014. The
system produces electricity from hydrogen generated as a by-product of a
sodium chlorate process at a high electric efficiency and is the first of its
kind in the Nordic Countries.
When scaled into commercial size, the equipment enables the reduction of
energy consumption of the electrolysis process used for sodium chlorate
production by 10–20%. The Kemira site’s annual electricity consumption is
approximately 578 GWh.
A few similar plants have been built elsewhere in the world, for example in
the Netherlands and North America.
The electric power of the pilot plant is approximately 50 kW. The total
electrical efficiency of the system, including the fuel utilisation ratio and
the power losses due to auxiliary equipment and power electronics, is
approximately 44%, while the fuel cell itself is operating at an electrical
efficiency of 54%. The power plant is based on PEM fuel cells - the same
technology that is considered most promising for the fuel cell vehicles.
At the moment, the low-temperature fuel cell at the Kemira Chemicals site
operates at approximately 60 °C. In the future, utilization of the waste heat
produced by the system is expected to also improve. This is achieved through
development of fuel cell materials, which enable higher operating temperatures.
One goal of the DuraDemo project, coordinated by VTT, has been to gather user
experience of operating a fuel cell system in an actual end-user application
in an industrial environment. The system performance has been recorded and
analysed to confirm the assumed level of readiness of PEMFC from technological
and commercial point of view and dealing with potential unresolved problems
related to this in the by-product hydrogen application.
The project also provided important information on the reliability of the
auxiliary systems and components, and the impact of using industrial-quality
hydrogen in PEM fuel cells. The strict quality standards governing the
utilisation of hydrogen as traffic fuel today are an important factor in the
price formation of hydrogen. In the future, a re-evaluation of these standards
may facilitate a major drop in the producer price of hydrogen.
The two-year DuraDemo research project, now nearing its end, has been part of
Tekes’ Fuel Cell technology programme. The project has been financed by the
following corporate partners: Kemira Chemicals Oy, Cargotec Finland Oyj,
Wärtsilä Finland Oy, ABB Oy, Leppäkosken Sähkö Oy, Konecranes Plc, Woikoski
Oy, MSc Electronics Oy, and the Federation of Finnish Technology Industries.