JOURNAL OF APPLIED ELECTROCHEMISTRY 17 (1987) 773-778 Performance of a pressurized electrochemical ozone generator S. STUCKI, H. BAUMANN, H. J. CHRISTEN, R. KOTZ Brown Boveri Research Center, CH-5405 Baden, Switzerland Received 17 September t986; 10 November 1986 The performance of a novel electrolytic ozone generator using a solid polymer electrolyte and a PbO2 anode is described. The operating parameters studied were: current density, water flow, temperature and pressure. Optimum current yields in the order of 20% are reached with a 30 cm 2 cell at a current of 40A, a temperature of 30~ and a volume feed rate of water > 301 h ~. T h e system pressure does not influence the current efficiency or the cell voltage. The specific power consumption of a state-of-the-art cell is in the order of 65 W h g 1. The technique has been applied commercially in the field of disinfection of purified water for more than 3 years. 1. Introduction 2. Experimental details Ozone is applied as an effective oxidant in water treatment for disinfection, decolouration and deodorization of drinking and industrial process water. An increasingly important aspect of ozone application in water treatment is its use as a disinfectant in purified water loops for the pharmaceutical and electronic industries [1 -3]. In these applications ozone is added to the pure water stream in very low concentrations in the order of 0.01 0.06gm -3, and guarantees full disinfection of the product water and the loop hardware. A new type of electrochemical ozone generator using a solid polymer electrolyte, instead of a liquid electrolyte, and lead dioxide anodes [4] has proved particularly useful in these applications: BBC-Membrel cells have accumu- lated more than 3 years of industrial application since their first introduction into pure water disinfection. First performance data of a cell of this type in a laboratory pure-water loop at atmospheric pressure were published previously [4]. The following article describes measure- ments which were obtained in a pressurized sys- tem which provided detailed information about the performance of the cell as a function of the operating parameters temperature, current den- sity, pressure and water flow. 0021-891X/87 $03.00 + .12 2.1. The cell A cell design similar to that previously described [4] was used for the present study. To allow pressure operation the cell was incorporated into an autoclave housing. Fig. 1 shows a sche- matic cross-section of the pressurized cell. The central element was formed by the membrane electrode assembly described elsewhere [4]. The active area of the cell was 30cm 2. The elec- trodes were held together by a solid cell hous- ing made of titanium and stainless steel. Lead dioxide was used as the ozone-evolving anode material throughout all the experiments. The cell components (electrodes and membrane) were exchanged for different experimental runs. 2.2. Control and instrumentation scheme The apparatus (see Fig. 2) was fed with deminer- alized water from a high pressure membrane metering pump. The water flowed through the anode compartment, taking up the anodically ~formed gases (ozone and oxygen). In a subse- quent static mixer the gas was dissolved in the water and fed to the UV absorption cell for analysis of the ozone concentration. The system 9 1987 Chapman and Hall Ltd. 773