Complete Oxidation of Volatile Organic Compounds

Harris RH, Boyd VJ, Hutchings GJ, Taylor SH (2002) Water as a promoter of the complete oxidation of volatile organic compounds over uranium oxide catalysts. Catal Lett 78 369... 

Three commercial processes, complete oxidation of volatile organic compounds (VOC) for purification of industrial exhaust gases, SO2 oxidation for sulfuric acid production, and NO reduction by ammonia, have employed the periodic flow reversal concept. In all cases the reaction Idnetics, including dynamic phenomena plays a crucial role. 

Mitsui, T.,Tsutsui, K.,Matsui,T.,cta/. (2008). Support Effect on Complete Oxidation of Volatile Organic Compounds over Ru Catalysts, Appl. Catal. B Environ, 81, pp. 56-63. 

Paulis, M Gandia, LM Gil, A Sambeth, J Odriozola, JA Montes, M. Influence of the surface adsorption-desorption processes on the ignition curves of volatile organic compounds (VOCs) complete oxidation over supported catalysts, Appl. Catal, B Environmental, 2000, Volume 26, Issue 1, 37-46. 

Complete oxidation of hydrocarbons in air is a useful method for atmospheric purification, and has been sucessfully applied in automotive exhaust control. An important new area is the catalytic control of the emissions of volatile organic compounds (VOC) in a more general sense [1]. Many sources, low concentrations and wide temperature ranges can be involved. 

Catalytic oxidation reactions on noble metal surfaces are sufficiently fast and exothermic that they can be operated at contact times on the order of one millisecond with nearly adiabatic temperatures of 1000°C. At short contact times and high temperatures complete reaction of the limiting feed is observed, and highly nonequilibrium products are obtained. We summarize experiments where these processes are used to produce syngas by partial oxidation of methane, olefins by partial oxidation of higher alkanes, and combustion products by total oxidation of alkanes. The former are used to produce chemicals, while the latter is used for high temperature catalytic incineration of volatile organic compounds. 

The development of active catalysts for total combustion of volatile organic compounds (VOCs) has been desired from foe viewpoint of environmental protection. Noble metal which possess high activity for total oxidation are widely applied to foe low temperature complete oxidation [1]. Moreover, it was shown that supports play an important role in catalytic activity and zeolites were widely used as powerful catalytic support [2-4]. Therefore, zeolites FAU and BEA exchanged with different alkali metal cations were prepared and 0.5wt% of palladium was incorporated in these supports. The catalysts obtained were calcined, characterised and tested for propene total oxidation. Some of these solids were also tested for VOCs adsorption. 

Within 6 months after enactment of the Qean Air Act Amendments of 1990, and at least every 3 years thereafter, the Administrator shall review and, if necessary, revise, the methods ( emission factors ) used for purposes of this Act to estimate the quantity of emissions of carbon monoxide, volatile organic compounds, and oxides of nitrogen from sources of such air pollutants (including area sources and mobile sources). In addition, the Administrator shall permit any person to demonstrate improved emissions estimating techniques, and following approval of such techniques, the Administrator shall authorise the use of such techniques. Any such technique may be approved only after appropriate public participation. Until the Administrator has completed the revision required by this section, nothing in this section shall be construed to affect the validity of emission factors established by the Administrator before the date of the enactment of the Clean Air Act Amendments of 1990. 

Low-volatility natural organic material such as polysaccharides and higher molecular weight proteins sometimes produced low results. In the Hannaker and Buchanan method [82] these problems are overcome by using a solution-phase oxidant and enclosing the system in a sealed tube. In this way all of the constituents are fully contained and exposed to oxidation and, moreover, oxidation of the organic matter to carbon dioxide is complete for the greater majority of compounds. 

Despite the fact that the destruction of toxic organic chemicals as fuels can be as high as 99.9%, with adequate residence time, many materials are more resistant (e.g., cholorobenzenes). Total COD reduction is usually only 75-95% or lower, indicating that while the toxic compounds may satisfactorily undergo destruction, certain intermediate products remain unoxidized. Because the wet-air oxidation is not complete, the effluent from the process can contain appreciable concentrations of volatile organics and may require additional treatment such as biological oxidation or adsorption on activated carbon [31]. 

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