PEM power plant converts by-product hydrogen to zero-emission electricity Making its contribution to a low carbon economy, DEMCOPEM-2MW uses a PEM fuel cell power plant to turn the by-product hydrogen from chlor-alkali factories, into electricity. The project is now ready to roll out at industrial scale. Energy © Jorg Coolegem Chlor-alkali (CA) production plants use electrolysis to turn brine – a solution of sodium chloride salt (NaCl) – into chlorine (Cl2) and caustic soda (NaOH). These products are important raw materials for the chemical industry, with the process relying on large amounts of electricity. As a by-product, the plants also produce high-purity hydrogen. In many CA plants, especially in China, this is simply released through venting. The DEMCOPEM-2MW project, has demonstrated that proton exchange membrane (PEM) technology can convert this hydrogen into electricity, heat and water, usable by CA power plants with environmental and economic benefits. DEMCOPEM-2MW received funding as part of the EU’s Joint Technology Initiatives – Collaborative Project initiative. Integrating PEM technology At the heart of the DEMCOPEM-2MW system lies the PEM fuel cells. These transform the chemical energy generated when hydrogen and oxygen electrochemically react with each other, into electrical energy. The critical part of the cells, where the reactions occur, is the so-called ‘triple phase boundary’ (TPB) where the electrolyte, catalyst, and reactants mix. “Installing PEM technology into factories to utilise hydrogen gas for the production of electricity, is relatively easy. The hydrogen is simply captured via a pipeline with the resulting electricity saving the CA factory up to 20 % of their electricity costs,” says scientific coordinator Mr Jorg Coolegem. The system is inherently sustainable as the only reactant is pure water – meaning no greenhouse gases, NOx, particulate matter or other harmful components are produced. The heat used during the process can also be used for example, to preheat the brine (necessary for electrolysis) and the demineralised water produced by the oxidation of hydrogen can also be used, for example to produce the brine. The installation is designed for 20 years of continuous operation. While the fuel cell stacks will be replaced several times over this period, they are designed so that most of the components can be recycled and reused. To keep manufacturing and maintenance costs down, the fuel cells, (especially membranes, electrodes and catalyst), are built for longevity and designed to minimise energy loss. The system functions automatically, running from a programmable logical controller (PLC), with monitoring (system diagnostics) and operation (for example to start/stop or change production capacity), performed remotely. Ready for roll out After the development of a 1 MW unit, the project reached another milestone with the current 2 MW system designed and built at the MTSA factory in The Netherlands. After the fuel cells, produced by Nedstack, were installed, the complete system was successfully tested. The technology is now ready to be rolled out. Indeed, a Factory Acceptance Test was successfully performed with Ynnovate in Yingkou, China, who have purchased the system. “China is the ideal market due to their high electricity prices, up to twice that of Europe, and given that they have 50 % of the world’s CA production, making efficient electricity vital,” says Mr Jan ten Have, technical coordinator. Aside from the markets where hydrogen is already a production by-product, another potential avenue could be Power to Power (P2P), where temporary renewable energy excess (e.g. from wind or solar) is stored as hydrogen. During renewable energy shortages, this hydrogen could be electrified using a PEM power plant. The technology could also be adopted by the transport sector, for example marine and rail. Keywords DEMCOPEM-2MW, energy, electricity, zero-emissions, low carbon economy, hydrogen, Proton Exchange Membrane, Chlor-alkali, brine, oxidation, renewable
