STUDY OF THE NON-CATALYTIC AND CATALYTIC OXIDATIVE DESTRUCTION OF VOCs

Abstract

In recent years, the release of volatile organic compounds (VOCs) has received much attention. Catalytic oxidation of VOCs, found in small concentration in industrial gas emissions constitutes an alternative for environmental pollution reduction. In this paper, a comparative study regarding the non-catalytic and catalytic oxidative destruction of non-halogenated or halogenated C 6 hydrocarbons (C 6 H 14 , C 6 H 12 , C 6 H 6 , Cl-C 6 H 5 , Br-C 6 H 5 ), is presented. Catalytic oxidation was studied in the presence of industrial V 2 O 5 -WO 3 /TiO 2 (0.53 %wt. V 2 O 5 ) catalyst, specific for SCR-DeNOx processes in high-dust system. Oxidative destruction was carried-out at 150 -350 0 C in dry and, respective, humid air stream (5 %vol. H 2 O), for low concentration of hydrocarbons in gas phase (< 100 ppm). The catalytic oxidation of hydrocarbons is partial, apart of CO 2 , also CO being detected at the end of the reaction. Study of noncatalytic oxidation of hydrocarbons showed that independent of the presence of water vapors, aromatic hydrocarbons do not react in gas phase. The acyclic hydrocarbons react in gas phase starting with the temperature of 300 0 C.

A Modelling Approach of the Catalytic Oxidation of Volatile Organic Compounds in the SCR-DeNOx Monolithic Reactor

“…V2O5), specific for the SCR-DeNOx process in high-dust system with low SO2/SO3 conversion. The main characteristics of the SCR-DeNOx commercial catalyst, according to the producers (CL-AS IHI-8070604/Japan), are presented in previous articles [20,21]. The commercial catalyst was used in a monolithic form, with parallel straight channels by square section (Figure 1).…”

“…https://doi.org/10.37358/RC.20.7.8227 This diagram of Figure 5 may be used for assessing at a given temperature the catalyst volume necessary for achieving a desired conversion of VOCs in a given flue gas flow rate. Considering that initial benzene concentration up to 150 ppm showed no influence on the conversion [20,21,37], the diagram may be used for benzene concentration in influent gas in the range 0 -150 ppm C6H6.…”

“…Monolithic catalysts offer a high specific geometric surface area and a low pressure drop, for use at high space velocities [4,5,13,14]. Considerable effort has been made to develop the SCR-DeNOx process for simultaneous removal of NOx and dioxine [1,7,9,[15][16][17] as well as VOC pollutants in flue gases using commercial V2O5-WO3/TiO2 catalyst [6,7,[18][19][20][21][22][23].…”

Comparative kinetics study of the catalytic oxidation of benzene and its mono-halogenated derivatives over V 2 O 5 –WO 3 /TiOLazar1, Koeser2, Balasanian3 2022Comptes Rendus. ChimieSelf Cite

“…Lazar et al [35] demonstrate that NO x selective catalytic reduction on V 2 O 5 -WO 3 /TiO 2 (0.53 wt% V 2 O 5 ) commercial catalyst can occur in parallel to benzene oxidation reaction, the presence of the latter not diminishing the efficiency of NO x reduction. Competition between VOC oxidation process and NO x selective catalytic reduction may be attributed to activities of the Lewis acid site of the SCR-DeNOx catalyst that, in the presence of water vapours, lead to formation of Brönsted acid site, responsible for nitrogen oxides conversion, but, on the other hand, may participate in benzene oxidation reaction.…”

“…Vanadia-based SCR-DeNOx catalysts show chlorine poisoning resistance [2,11,29,[32][33][34]. Researchers have demonstrating that the use of V 2 O 5 -WO 3 /TiO 2 commercial catalysts (by IHI/Japan) is a viable alternative for treatment of gas emissions with a low content of VOCs [35][36][37], and for oxidation of the mercury from gaseous emissions [38][39][40]. The most often applied SCR-DeNOx catalyst consists of vanadia on titania support, with the addition of WO 3 to increase the temperature window, SiO 2 to stabilize the structure and MoO 3 to make the catalyst more resistant towards poisoning by SO 2 [2,11,34,41].…”