(Credit: Kemira Chemicals)
VTT Technical Research Center of Finland has developed a pilot-scale power plant based on fuel cells that utilizes by-product hydrogen from sodium chlorate production. The power plant has been in operation at Kemira Chemicals Oy’s site in Finland since January 2014.
Sodium chlorate is an inorganic compound used mainly for applications in bleaching paper. Several hundred million tons of this chemical are produced annually. Industrially, sodium chlorate is produced by the electrolysis of a hot sodium chloride solution, with hydrogen as a by-product. The pilot plant now uses this hydrogen to produce electricity.
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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 GW·h.
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 utilization 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 (polymer electrolyte membrane) 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 (140 °F). 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 analyzed 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 utilization 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 program. 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.