Oxygen recovery from ozone generators by adsorption processes

• Published in: Adsorption : journal of the International Adsorption Society 2023-02, Vol.29 (2), p.73-86
• Main Author: Luberti, Mauro
• Format: Article
• Language: English
• Subjects: Adsorption; Allotropy; Chemistry; Chemistry and Materials Science; Energy consumption; Engineering Thermodynamics; Generators; Heat and Mass Transfer; Industrial Chemistry/Chemical Engineering; Nitrogen; Oxidation; Oxygen consumption; Ozone; Purity; Surfaces and Interfaces; Thin Films
• ISSN: 0929-5607; 1572-8757
• DOI: 10.1007/s10450-023-00377-z

As a triatomic allotrope of oxygen, ozone has many industrial and consumer applications because of its high oxidation potential and disinfectant properties. Most of the ozone is currently produced by corona discharge reactors using high-purity oxygen as the feed gas, where the conversion to ozone is typically 6−15 wt%. Given the high operating costs associated with the unreacted oxygen, it is essential to recover the oxygen for recycling to the ozone generator. This paper aims for the first time to design, simulate and assess cyclic adsorption processes for recovering oxygen from a mixture of ozone and oxygen (O 3 :O 2  = 10:90 wt%) produced by a commercial ozone generator. A 2-bed, 2-step cycle was first investigated in which ozone is selectively adsorbed at high pressure and then desorbed by dry air used as a sweep gas. However, it was found that the O 2 purity in the recycle stream was too low because of the nitrogen build up from air. Thus, two additional cycles, namely a 3-bed, 3-step cycle incorporating an oxygen purge step and a 3-bed, 4-step cycle incorporating a vacuum blowdown step, were evaluated with the purpose of removing nitrogen from the bed after the desorption step. Both adsorption cycles achieved a satisfactory O 2 purity of 98+% in the recycle stream with a sacrifice of O 2 recovery and an increase in energy consumption, respectively. As a result, the adsorption processes devised in this study could serve to significantly reduce the oxygen consumption in industrial ozone generators.