Regular Article

Ozone yield limit in low temperature plasmas based on thermodynamics

¹ Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, School of Environmental and Chemical Engineering, Nanchang University, Nanchang 330031, P.R. China
² Electrical, Electronic and Information Engineering Department, University of Bologna, Bologna 40136, Italy

^a e-mail: weilinsheng@ncu.edu.cn

Received: 14 October 2018
Received in final form: 9 March 2019
Published online: 2 July 2019

Abstract

To investigate ozone yield limit in low temperature plasmas, a detailed thermodynamic model is developed to calculate theoretical ozone yield for the first time. Theoretical ozone yield is calculated both from overall reaction and detailed reactions. In the former case, the highest theoretical ozone yield of 1211 ± 2 g kWh⁻¹ is obtained when final gas temperature equals the initial one, and all energy is effectively utilized to synthesize ozone. When final gas temperature is not equal to the initial one, theoretical ozone yield increases with the increase of oxygen admixture ratio and oxygen conversion ratio as well as the decrease of final gas temperature. Theoretical ozone yields are 921.22 g kWh⁻¹ and 487.54 g kWh⁻¹ in pure oxygen and in synthetic air respectively at final gas temperature of 400 K and oxygen conversion ratio of 10%. When detailed reactions and electron energy distribution function is considered, theoretical ozone yield rapidly increases by enhancing reduced field. Oxygen admixture ratio also has non-negligible effects on ozone yield. A higher oxygen admixture ratio leads to higher energy efficiency. The theoretical ozone yields are 238.92 g kWh⁻¹ and 191.14 g kWh⁻¹ in pure oxygen and in synthetic air at reduced field of 300 Td respectively.