Techno-economic assessment of adsorption processes to recover oxygen from ozonizers

Abstract

Industrial ozonizers are normally fed with high-purity oxygen and can reach conversions to ozone in the range of 6–15 wt%. Because of these low conversion values, adsorption technology has been proposed to recover most of the unreacted oxygen for recycling to the ozonizer and substantially improve the overall process economics. In this work, it was aimed to design and assess two adsorption processes, a 3-bed 3-step system and a 3-bed, 4-step system, with the purpose of recovering an oxygen stream with a purity of 98.5%, as to not adversely affect the ozonizer performance. Both systems achieved the target oxygen purity with oxygen recoveries >90% for various adsorption pressures ranging 1.5–3.0 bar. Furthermore, an in-depth economic analysis taking into account both CAPEX and OPEX contributions revealed that the 3-bed, 3-step system was marginally more profitable than the 3-bed, 4-step system. Given that the total annualized cost associated with the adsorption systems was considerably lower than the cost of the recovered high-purity oxygen, the integrated ozonizer-adsorption process led to net savings of 85–89% compared to the standalone ozonizer.