Incineration Of Volatile Organic Compounds Research Articles

Comparative life cycle assessment of plasma-based and traditional exhaust gas treatment technologies

The emissions of airborne contaminants from various industrial processes are an important source of air pollution and presents problems for human health and the environment in general. The removal of gaseous pollutants, such of nitrogen and sulphur oxides (NOx and SOx), from exhaust gases, or volatile organic compounds (VOC) emitted from various industrial processes is of continuous challenge in the environmental engineering. Plasma-based pollutant decomposition methods emerge as promising techniques, but little is known about their overall environmental performance. We compared two plasma based technologies (Electron Beam Flue Gas Treatment (EBFGT) and Dielectric Barrier Discharge (DBD) against the conventional methods (Wet Flue Gas Desulphurization with Selective Catalytic Reduction, WFGD+SCR, biofiltration and adsorption) using life cycle analysis (LCA), which took into account the usage of materials, waste generation and energy consumption. Five main categories (Global Warming, Ozone Layer Depletion, Acidification, Euthrophication and Human Toxicity, based on the CML2001 method) were used for the environmental impact evaluation. Based on CML2001 IKP Experts weighting, WFGD+SCR technology is marginally more environmentally friendly in comparison to EBFGT (59.25 to 73.74 CML2001 IKP Experts score). The generation of byproducts (in this case gypsum waste) is the main disadvantage of the WFGD+SCR. At the same time, EBFGT enables formation of useful byproducts, which are suitable to be utilized as fertilizers in the agriculture sector. On the other hand, DBD was six times more favorable to the environment than the adsorbtion and more than two times more environmentally friendly than the biofiltration technology (4.23, 27.78 and 9.29 relative units, respectively). With respect to the adsorption/thermal incineration of VOCs, both the electricity and the material consumption, as well as the management of byproducts caused the highest impact. In case of biofiltration, the management of remaining filter material waste (in this case, landfilling) was the most significant. Relatively high electrical energy demand causes lower positioning of plasma based technologies in cases where no other materials are utilized and major waste is formed. In turn, many traditional end-of pipe technologies are associated with high amounts of process waste, which provides plasma technologies with an opportunity to establish them in the market as more efficient and in many occasions, more environment-friendly ones.

Correlation of electrical properties of nanometric copper-doped ceria materials (Ce1−xCuxO2−δ) with their catalytic activity in incineration of VOCs

The nanometric copper doped Ce1 − xCuxO2 − δ materials were obtained using a modified reverse nanoemulsion method followed by a previously optimized calcination. XRD patterns confirmed the presence of only one, fluorite-like CeO2 phase, within the range of 0 < x < 0.12, in accordance with embedding Cu ions in the CeO2 phase. High increase of catalytic activity in oxidative incineration of volatile organic compounds (VOCs) with Cu-doping was observed, equally with a high increase in the ionic conductivity related to the increase of concentration of oxygen vacancies in the ceria lattice. The impedance spectroscopy allowed to specify that the high catalytic activity of Ce1 − xCuxO2 − δ is bounded also with change of the share in ionic and electronic conductivities. Though, the active catalyst should reveal mixed ionic and electronic conductivities (MIEC), the higher share of ionic component of electrical conductivity seems to be essential. Such a conclusion is in accordance with the Mars–van Krevellen model of catalytic oxidation of VOC molecules.

Effect of Concentration by Thermal Swing Adsorption on the Catalytic Incineration of VOCs

Abstract Among the different processes for elimination of volatile organic compounds (VOCs) from gaseous effluents (mainly air streams), the frequently employed catalytic oxidation is undertaken in this contribution. With the purpose of reducing the amount of catalyst needed for incineration and the surface of recuperative heat exchangers, thermal swing adsorption can be use as a previous step for VOC concentration.By means of simulating the behavior of a conventional packed bed reactor and using kinetic expressions recently developed for the incineration of mixtures of ethyl acetate and ethanol on a laboratory catalyst based on Mn/Cu oxides, it is shown in this paper that the reduction in catalyst volume is significantly larger than the concentration factor, due to the combined effect of the lower flow rate and temperature rise.A second aspect dealt with in this contribution concern the simulation of the packed bed reactor. The intraparticle mass-transfer limitations turn out to be very strong and, consequently, the mass conservation balances of three species inside the particles should be solved numerically and iteratively at each position inside the bed. A precise approximation to circumvent such procedure is developed and shown to reduce computing time in more than one order of magnitude and to avoid convergence troubles otherwise found with the numerical procedure.

Glass-fiber catalysts: Novel oxidation catalysts, catalytic technologies for environmental protection

Novel glass-fiber based catalysts containing extra-low amounts of noble metals (0.01–0.02 mass% of Pt or Pd) demonstrate unique performance in many catalytic reactions, resulted from the ability of the glass fibers to stabilize the transient metals in the glass bulk in a highly dispersed form. Moreover, specific heat/mass transfer properties, original geometry, high flexibility and high mechanical strength of such catalysts give the way to develop really new catalytic processes and novel reactor designs. The paper is dedicated to the successful research and development (from fundamental research issues to pilot and semi-industrial tests) of different catalytic oxidation processes based on application of fiber-glass catalysts for solution of various environmental problems, namely: purification of automotive exhausts, incineration of VOCs (volatile organic compounds) in waste/vent gases, utilization of chlorinated VOCs and dioxins abatement in waste gases, sulphur dioxide oxidation for purification of waste gases and for conditioning of flue gases of coal-fired powerplants.

Application of polyol process to prepare AC-supported nanocatalyst for VOC oxidation

Abstract The purposes of this study were to prepare a transition-metal catalyst by the polyol method, and subsequently to evaluate the feasibility of the catalytic incineration of volatile organic compounds (VOCs). Activated carbon (AC) was selected as the support material, and copper, cobalt, iron, and nickel were used as the catalytic active phases. The catalyst was characterized by UV–vis, Brunauer–Emmett–Teller (BET) surface area, X-ray powder diffractometer (XRPD), and field emission scanning electron microscopy (FESEM). The catalysts prepared by the polyol process exhibited well-dispersed nanoscale metal particles. Increases in the reduction time and in the particle size led to a lower toluene conversion. The activity of metal/AC with respect to metal was observed to follow a particular order: Cu > Co > Fe > Ni. Increasing the reaction temperature and decreasing the toluene concentration and space velocity resulted in better VOC conversion. The activity of Cu/AC with respect to the VOC molecule was observed to follow the following sequence: xylene > toluene > benzene. The results indicated that the polyol process could successfully be used to manufacture nanocatalysts that could be applied to eliminate VOCs by catalytic incineration.

Thermal recuperative incineration of VOCs: CFD modelling and experimental validation

A numerical 2D model of a thermal recuperative incinerator (TRI) used to oxidise volatile organic compounds (VOCs) diluted in an air flow was developed to simulate the coupled equations for flow, heat transfer, mass transfer and progress of chemical reactions. The model was confronted with experimental values obtained on a highly instrumented half-industrial-scale pilot unit run under the same conditions. The model indicates that the flow inside the reactor is close to the ideal situation of a plug flow reactor. Nevertheless, a non-symmetric flow is retrieved despite the symmetrical arrangement of the combustion chamber. The model confirms that the most constraining phenomenon is the oxidation of CO. The formation of CO results of the combustion of the VOCs, and not from the combustion of the methane fed into the burner. The models demonstrated that the CO destruction reaction is controlled by the micro-mixing efficiency in a large part of the reactor, and not by the chemical kinetics of the reaction. This indicates the need for installing additional turbulence devices in order to enhance the turbulence level in a zone established from this modelling. The model establishes that thermal NO is formed in the flame zone of the burner, and is not due to VOC oxidation. These results together indicate that concentrating VOCs in an air flux prior to its treatment by a TRI will limit CO 2 emissions and NO emissions together.

Efficient Equipment with Special Heat Exchanger for Thermal Treatment of Polluted Air—Experiments, Computations, Applications

A quite new and unique piece of equipment for the thermal treatment of gas wastes (i.e., the incineration of volatile organic compounds contained in polluted air) has been developed. This compact equipment is characterized by a cylindrical combustion chamber placed inside a heat exchanger—a polluted air preheater. This cylindrical preheater consists of several concentric stainless sheets. Both flue gas from the combustion chamber and polluted air heated by flue gas flow in the spaces between the cylindrical sheets. Narrow distance strips placed between the sheets form helical rectangular ducts, through which we can achieve a counter-current flow of process fluids.A mathematical model for the calculation and/or simulation of the equipment consists of submodels of a heat exchanger and combustion chamber and the annular space between them. Based on the results of measurements on an industrial scale experimental facility, new correlations for the thermal and hydraulic calculations of the heat exchanger were developed. Some industrial applications are briefly mentioned.

Alternative arrangement of unit for thermal processing of wastes from polluted air

New efficient equipment for the thermal treatment of gas wastes from polluted air (incineration of volatile organic compounds and carbon monoxide) has been developed recently. This equipment can be used in various branches of industry (for the treatment of polluted air from paint shops, chemical cleaning systems, degreasing processes, printing machines, gas wastes from various chemical processes, for the thermal treatment of off-gases originating in refineries, in the production of plastic, the pharmaceutical industry, the food industry, laboratories, etc.). A principal idea of this equipment is based on placing the cylindrical combustion chamber inside a heat exchanger–polluted air preheater. Main advantages of this equipment are as follow: compactness and utilizing heat losses from the combustion chamber for additional preheating the polluted gas. Modified equipment for catalytic treatment can be used as an alternative unit. Various options of arrangement can be applied in industrial practice. This unit can be used as a compact one (minimization of space requirement owing to a convenient arrangement of fans), over pressure (only air fan), under pressure (only flue gas fan — recommended especially in cases where the polluted air is supplied by pressure). Waste to energy arrangement is that in the case of an excessive concentration of pollutants–combustibles. Then the energy of the outlet flue gas can be utilized not only for the polluted air preheating but also for steam generation, water heating or other purposes.

Fully integrated unit for thermal treatment of gas wastes

A range of methods is used for the treatment of gas or liquid organic compounds. The thermal treatment of wastes can be considered as one of the most frequently used and most efficient processes. This method is based on a high temperature oxidising organic compounds by oxygen from air when inert (i.e. not harmful) gases like CO 2 and H 2O are generated. A new equipment for the thermal treatment of gas wastes i.e. incineration of volatile organic compounds and carbon monoxide contained in polluted air has been developed. This is in fact a process for the thermal treatment of this type of wastes placed into one compact equipment consisting of a combustion chamber (incinerator) combined with heat exchanger (polluted air preheater). This equipment can be used in various branches of industry (for the treatment of polluted air from paint shops, chemical cleaning systems, degreasing processes, printing machines, gas wastes from various chemical processes, for the thermal treatment of off-gases originating in refineries, in production of plastics, pharmaceutical industry, food industry, laboratories, etc.). Principal steps in the research and development are briefly described as follows: idea and basic conception, design geometry, using simulation for setting basic process parameters, developing a computer program for thermal and hydraulic calculation of this equipment, design of a research facility in an industrial scale, experimental research and measurements, a procedure for verification mathematical models including computational fluid dynamics simulation, recommendation for industrial application.

Kinetics of Catalytic Oxidation of Benzene, n-Hexane, and Emission Gas from a Refinery Oil/Water Separator over a Chromium Oxide Catalyst

ABSTRACT With the advances made in the past decade, catalytic incineration of volatile organic compounds (VOCs) has become the technology of choice in a wide range of pollution abatement strategies. In this study, a test was undertaken for the catalytic incineration, over a chromium oxide (Cr2O3) catalyst, of n-hexane, benzene, and an emission air/vapor mixture collected from an oil/water separator of a refinery. Reactions were carried out by controlling the feed stream to constant VOC concentrations and temperatures, in the ranges of 1300–14,700 mg/m3 and 240–400 ° C, respectively. The destruction efficiency for each of the three VOCs as a function of influent gas temperature and empty bed gas residence time was obtained. Results indicate that n-hexane and the oil vapor with a composition of straight- and branch-chain aliphatic hydrocarbons exhibited similar catalytic incineration effects, while benzene required a higher incineration temperature or longer gas retention time to achieve comparable results. In the range of the VOC concentrations studied, at a given gas residence time, increasing the operating temperature of the catalyst bed increased the destruction efficiency. However, the much higher temperatures required for a destruction efficiency of over 99% may be not cost-effective and are not suggested. A first-order kinetics with respect to VOC concentration and an Arrhenius temperature dependence of the kinetic constant appeared to be an adequate representation for the catalytic oxidation of these volatile organics. Activation energy and kinetic constants were estimated for each of the VOCs. Low-temperature destruction of the target volatile organics could be achieved by using the Cr2O3 catalyst.

Catalytic incineration of VOC containing air streams at very short contact times

AbstractA short‐contact‐time catalytic combustor described here is capable of incinerating air streams with low concentrations of volatile organic compounds (VOCs) at conversions exceeding 99.5% for contact times on the order of 5 ms. This is accomplished by adding methane to the VOC‐containing air stream to increase the fuel stream value and then passing the mixture over a platinum‐coated foam ceramic monolith at 900 – 1,400°C. The incineration of air streams containing toluene, chlorobenzene, acetonitrile, and thiophene was examined at concentrations ranging from 500 to 2,000 PPM. Residence time and methane concentration do not affect strongly the outlet concentration of the VOC and conversion. Greater than 99.5% conversion is observed for all compounds examined for residence times ranging from 4 to 12 ms and methane concentrationsfrom 5.5 to 7.0% (80–40% excess air). The mechanism of reaction in this system is primarily heterogeneous, with some homogeneous reactions driven by the heat liberated by the heterogeneous reactions. A simple homogeneous model shows that homogeneous chemistry alone cannot account for complete conversion of the additional methane fuel at the reaction conditions described.

Development of the adsorption-catalytic reverse-process for incineration of volatile organic compounds in diluted waste gases

Development of adsorption-catalytic reverse-process, based on adsorption of volatile organic compounds (VOC) on the surface of oxide catalyst with periodical incineration of accumulated compounds, applying reverse-flow operation technique is described. Process fundamentals were studied on the base of mathematical model, accounting for heat and mass transfer between gas and catalyst, heat conductivity of the catalyst bed frame, physical adsorption/desorption and irreversible chemisorption of VOC and oxidation of surface compounds. Mathematical modeling showed the high purification efficiency (higher than 99.9%) combined with extremely low energy consumption of the proposed process (less than 1–3 kJ per m 3 of waste gas) in the case of processing of waste gases with low VOC content (below 0.8 g/m 3). Results of pilot tests, confirming theoretical results, are presented in the paper.

Thermal and catalytic incineration of volatile organic compounds

Abstract A major control strategy for dilute waste streams of volatile organic compounds (VOCs) in air is incineration. However, no single incineration technology will likely serve as the optimal solution for all applications. In addition, with increasing VOC regulation, more variations of incineration or oxidation systems are appearing in the marketplace. This review presents a description of the currently available incinerator systems in the light of basic combustion theory. It is intended that this overview provide potential users with sufficient background to evaluate the various technologies for application to their specific waste stream. The discussion is presented in two parts. The first deals with thermal or gas‐phase oxidation reactions and those incinerators that employ the thermal pathway for VOC destruction. Both recuperative and regenerative systems are described in this part of the review. The second part treats catalytic incinerators with the same emphasis on underlying principles. The discussion is concluded with two case studies illustrating both methods of incineration.

Kinetics and transport parameters for the fixed-bed catalytic incineration of volatile organic compounds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics and transport parameters for the fixed-bed catalytic incineration of volatile organic compoundsAlbert C. Frost, John E. Sawyer, Jerry C. Summers, Yatish T. Shah, and Carlos G. DassoriCite this: Environ. Sci. Technol. 1991, 25, 12, 2065–2070Publication Date (Print):December 1, 1991Publication History Published online1 May 2002Published inissue 1 December 1991https://doi.org/10.1021/es00024a012RIGHTS & PERMISSIONSArticle Views233Altmetric-Citations5LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts