Fire from ordinary water
Water electrolysis and electrolyser technologies are not new. However, their widespread adoption in brazing metals has been limited by the high costs of membranes and catalysts containing platinum or other precious metals needed for the electrolysers to operate. The SAFEFLAME (Development of oxy-hydrogen flame for welding, cutting and brazing) project has used the funding to make this technology affordable. The aim was to develop an attractive alternative to the commonly used brazing torches and gas cylinders. The pressurised gas in cylinders is highly flammable. The cylinders are heavy which raises safety concerns about storage and transportation. Project chemists formulated new membranes to increase the performance of the electrolyser. They also investigated new catalysts and different ways to form the structure of the catalysts in an effort to reduce the amount of platinum and replace it with lower cost alternatives. Research work carried out during the SAFEFLAME project resulted in a significant reduction in the cost of electrolyser systems. It has been calculated that the running cost for the new unit could be 20 times cheaper, when considering the elimination of gas cylinder hire and transport charges. The SafeFlame system works using electricity and water. It’s an on-demand low pressure system, there are no stored gases. An electrical current is applied to demineralised water to separate hydrogen from oxygen. The gases produced are ignited at the torch's nozzle. By adjusting the proportions of the two gases, different types of flames can be obtained. Because the gases are recombined at the torch nozzle the flame produced is safe and easy to work with. Less heat is transferred to the torch therefore skin burns are less likely and “lightback” is eliminated. As the flame is controllable and the work piece remains highly visible, it is also possible to process high and low melting point metals safely. Prototype SAFEFLAME units have been developed and tested on brazing metal joins such as: radiator coils, pipework, copper and aluminium systems, a commercial roll-out is planned for the near future.
Keywords
Electrolyser, hydrogen, metal brazing, water electrolysis, oxygen-acetylene
