Energy optimisation and layout of a membrane-free OSEC system for the hypochlorite self-production in Developing Countries

The production of hypochlorite in an OSEC (On Site Electrochemical Chlorination) system occurs through electrolysis of a saline solution, with a hydrogen production that is usually discarded. The OSEC system described in this work - presently used in Gaza - has been optimised for use in Tanzania. The first approach focused on the possibility to use the OSEC System in Tanzania, by feeding it through a suitably designed photovoltaic generator allowing the energy independence of the entire process. The aim was to prove how an accurate sizing represents the basis for a good OSEC-feeding without MPPT and DC/DC converter devices, as well as how the electrolytic solution concentration is crucial. The second approach aimed at proving the possibility to exploit hydrogen in a fuel cell by recovering the hydrogen produced during the electrolysis of a saline solution in a membrane-free OSEC system, working in batch mode. Furthermore, an accurate analysis highlighted how and to what extent the presence of oxygen produced during the electrolysis process may limit the efficiency of the fuel cell (in our case, by 25%). More specifically, it was observed that if the percentage of oxygen volume is kept under 11-12%, a limited power loss is registered in the fuel cell; consequently, fuel cell efficiency may reach 40%, and the ensuing energy recovery may almost reach 13%. Finally, an indication of how to possibly limit the presence of oxygen is also provided. (C) 2013 Elsevier Ltd. All rights reserved.