Download or read book Simultaneous Control of NOx and Organic Particles Using Plasma Assisted Catalysis written by and published by . This book was released on 2001 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water and higher concentrations of oxygen present in diesel and turbine combustion exhausts inhibit and deactivate selective reduction (SCR) catalysts that are effective in removing NOx from internal combustion engine exhausts. Ox idation of NO to NO2, the slow step in SCR treatment, is accomplished rapidly as a competing process during plasma-catalyzed oxidation of hydrocarbon (HO) fuels in exhausts. Reduction of NO2 so formed is effected by passage of the heated stream through a bed of alumina of practically any configuration. Two-stage reactors to perform these steps were assembled and tested at bench-, pilot- and full-scale on exhaust from a 5.9-L Cummins diesel engine. The process, called plasma-assisted catalytic reduction (PACR), removed 95% of NOx at pilot scale using propene as the HO. Diesel fuel was used in the three sets of engine tests, and under these conditions PACR consistently achieved 50-55% reduction of NOx at a net fuel penalty of 5% to operate the control. Fuel sulfur did not affect the PACR process, and SO2 was not oxidized. Conduction across the high-voltage insulator was observed as a problem, but oxidation of deposited soot by the plasma was also observed and the system could be reconfigured using the plasma to prevent soot accumulation. Fuel cracking to enhance NO2 reduction was proposed but not tested.

Download or read book Nox Reduction for Lean Exhaust Using Plasma Assisted Catalysis written by and published by . This book was released on 2000 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Currently CARB estimates on road diesel vehicles contribute 50% of the NOX and 78% of the particulates being discharged from mobile sources. Diesel emissions obviously must be reduced if future air quality targets are to be met. A critical technological barrier exists because there are no commercial technologies available, which can reduce NOX from diesel (lean), exhaust containing 5-15% O2 concentration. One promising approach to reducing NOX and particulates from diesel exhaust is to use a combination of plasma with catalyst. Plasma can be generated thermally or non-thermally. Thermal plasma is formed by heating the system to an exceedingly high temperature (>2000 C). High temperature requirements for plasma makes thermal plasma inefficient and requires skillful thermal management and hence is considered impractical for mobile applications. Non-thermal plasma directs electrical energy into the creation of free electrons, which in turn react with gaseous species thus creating plasma. A combination of non-thermal plasma with catalysts can be referred to Plasma Assisted Catalysts or PAC. PAC technology has been demonstrated in stationary sources where non-thermal plasma catalysis is carried out in presence of NH3 as a reductant. In stationary applications NO is oxidized to HNO3 and then into ammonium nitrate where it is condensed and removed. This approach is impractical for mobile application because of the ammonia requirement and the ultimate mechanism by which NOX is removed. However, if a suitable catalyst can be found which can use onboard fuel as reductant then the technology holds a considerable promise. NOX REDUCTION FOR LEAN EXHAUST USING PLASMA ASSISTED CATALYSIS Ralph Slone, B. Bhatt and Victor Puchkarev NOXTECH INC. In addition to the development of an effective catalyst, a non-thermal plasma reactor needs be scaled and demonstrated along with a reliable and cost effective plasma power source and onboard HC source needs to be proven. Under the work sponsored by DOE and SCAQMD Noxtech is developing a cost effective and reliable PAC system for mobile applications. The goal of the program is to develop a suitable catalyst with the ability to remove high levels of NOx at reasonable space velocities. This new catalyst will then be used to scale the technology to treat exhaust from 80Hp engine and eventually to demonstrate the technology on 200 and 400 Hp engine applications. Using the 2004 EPA proposed regulation as a standard, it is clear in order for PAC system to be commercially viable it needs to remove NOX by 70% or better. It is further assumed from past experience that 30,000 HR-1 space velocities are necessary to ensure a good compact design.

Download or read book Plasma Chemistry and Catalysis in Gases and Liquids written by Vasile I. Parvulescu and published by John Wiley & Sons. This book was released on 2013-03-19 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filling the gap for a book that covers not only plasma in gases but also in liquids, this is all set to become the standard reference for this topic. It provides a broad-based overview of plasma-chemical and plasmacatalytic processes generated by electrical discharges in gases, liquids and gas/liquid environments in both fundamental and applied aspects by focusing on their environmental and green applications and also taking into account their practical and economic viability. With the topics addressed by an international group of major experts, this is a must-have for scientists, engineers, students and postdoctoral researchers specializing in this field.

Download or read book Plasma Aftertreatment for Simultaneous Control of NOx and Particulates written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma reactors can be operated as a particulate trap or as a NO(subscript x) converter. The soluble organic fraction (SOF) of the trapped particulates can be utilized for the oxidation of NO to NO2. The NO2 can then be used to non-thermally oxidize the carbon fraction of the particulates. This paper examines the energy density required for oxidation of the SOF hydrocarbons and the fate of NO2 during the oxidation of the particulate carbon. The energy density required for complete oxidation of the SOF hydrocarbons is shown to be unacceptably large. The reaction of NO2 with carbon is shown to lead mainly to backconversion of NO2 to NO. These results suggest that the use of a catalyst in combination with the plasma will be required to efficiently reduce the NO(subscript x) and oxidize the SOF hydrocarbons.

Download or read book Nitrogen oxides NOx why and how they are controlled written by and published by DIANE Publishing. This book was released on 1999 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Feasibility of Plasma Aftertreatment for Simultaneous Control of NOx and Particulates written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma reactors can be operated as a particulate trap or as a NOx converter. Particulate trapping in a plasma reactor can be accomplished by electrostatic precipitation. The soluble organic fraction of the trapped particulates can be utilized for the hydrocarbon- enhanced oxidation of NO to NO2. The NO2 can then be used to non-thermally oxidize the carbon fraction of the particulates. The oxidation of the carbon fraction by NO2 can lead to reduction of NOx or backconversion of NO2 to NO. This paper examines the hydrocarbon and electrical energy density requirements in a plasma for maximum NOx conversion in both heavy-duty and light-duty diesel engine exhaust. The energy density required for complete oxidation of hydrocarbons is also examined and shown to be much greater than that required for maximum NOx conversion. The reaction of NO2 with carbon is shown to lead mainly to backconversion of NO2 to NO. These results suggest that the combination of the plasma with a catalyst will be required to reduce the NOx and oxidize the hydrocarbons. The plasma reactor can be operated occasionally in the arc mode to thermally oxidize the carbon fraction of the particulates.

Download or read book SELECTIVE REDUCTION OF NOX IN OXYGEN RICH ENVIRONMENTS WITH PLASMA ASSISTED CATALYSIS written by and published by . This book was released on 2003 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: The control of NOx (NO and NO2) emissions from so-called ''lean-burn'' vehicle engines remains a challenge. In recent years, there have been a number of reports that show that a plasma device combined with a catalyst can reduce as high as 90% or more of NOx in simulated diesel and other ''lean-burn'' exhaust. In the case of propylene containing simulated diesel exhaust, the beneficial role of a plasma treatment is now thought to be due to oxidation of NO to NO2, and the formation of partially oxidized hydrocarbons that are more active for the catalytic reduction of NO2 than propylene. Thus, the overall system can be most usefully described as hydrocarbon selective catalytic reduction (SCR) enhanced by 'reforming' the exhaust with a non-thermal plasma (NTP) device. For plasma-enhanced catalysis, both zeolite- and alumina-based materials have shown high activity, albeit in somewhat different temperature ranges, when preceded by an NTP reactor. This paper will briefly describe our research efforts aimed at optimizing the catalyst materials for NTP-catalysis devices based, in part, on our continuing studies of the NTP- and catalytic-reaction mechanisms. Various alkali- and alkaline earth-cation-exchanged Y zeolites have been prepared, their material properties characterized, and they have been tested as catalytic materials for NOx reduction in laboratory NTP-catalysis reactors. Interestingly, NO2 formed in the plasma and not subsequently removed over these catalysts, will back-convert to NO, albeit to varying extents depending upon the nature of the cation. Besides this comparative reactivity, we will also discuss selected synthesis strategies for enhancing the performance of these zeolite-based catalyst materials. A particularly important result from our mechanistic studies is the observation that aldehydes, formed during the plasma treatment of simulated diesel exhaust, are the important species for the reduction of NOx to N2. Indeed, acetaldehyde has been found to be especially effective in the thermal reduction of both NO and NO2 over Ba- and Na-Y zeolite catalysts.

Download or read book Plasma Assisted Heterogeneous Catalysis for NOx Reduction in Lean Burn Engine Exhaust written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent developments in catalytic control of NOx are revealing the significance of NO2 as an intermediary for achieving higher NOx removal efficiencies. This paper discusses the combination of the plasma with a catalyst to improve the selective reduction of NOx under lean-burn conditions. It is shown that the main effect of the plasma is to enhance the gas-phase oxidation of NO to NO2. The reduction of NOx to N2 is then accomplished by the heterogeneous reaction of NO2 with activated hydrocarbons on the catalyst surface. By using a plasma, one can take advantage of a new class of catalysts that are potentially more durable, more active, more selective and more sulfur-tolerant compared to conventional lean-NOx catalysts. The plasma-assisted catalytic reduction process can be implemented with any type of plasma reactor and does not require a specific type of electrical power supply. It can also easily accommodate any type of catalyst support structure.

Download or read book Plasma Catalysis written by Annemie Bogaerts and published by MDPI. This book was released on 2019-04-02 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma catalysis is gaining increasing interest for various gas conversion applications, such as CO2 conversion into value-added chemicals and fuels, N2 fixation for the synthesis of NH3 or NOx, methane conversion into higher hydrocarbons or oxygenates. It is also widely used for air pollution control (e.g., VOC remediation). Plasma catalysis allows thermodynamically difficult reactions to proceed at ambient pressure and temperature, due to activation of the gas molecules by energetic electrons created in the plasma. However, plasma is very reactive but not selective, and thus a catalyst is needed to improve the selectivity. In spite of the growing interest in plasma catalysis, the underlying mechanisms of the (possible) synergy between plasma and catalyst are not yet fully understood. Indeed, plasma catalysis is quite complicated, as the plasma will affect the catalyst and vice versa. Moreover, due to the reactive plasma environment, the most suitable catalysts will probably be different from thermal catalysts. More research is needed to better understand the plasma–catalyst interactions, in order to further improve the applications.

Download or read book Plasma Assisted Catalytic Reduction of NOx written by and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies suggest that lean-NOx SCR proceeds via oxidation of NO to NO2 by oxygen, followed by the reaction of the NO2 with hydrocarbons. On catalysts that are not very effective in catalyzing the equilibration of NO+O2 and NO2, the rate of N2 formation is substantially higher when the input NOx is NO2 instead of NO. The apparent bifunctional mechanism in the SCR of NOx has prompted the use of mechanically mixed catalyst components, in which one component is used to accelerate the oxidation of NO to NO2, and another component catalyzes the reaction between NO2 and the hydrocarbon. Catalysts that previously were regarded as inactive for NOx reduction could therefore become efficient when mixed with an oxidation catalyst. Preconverting NO to NO2 opens the opportunity for a wider range of SCR catalysts and perhaps improves the durability of these catalysts. This paper describes the use of a non-thermal plasma as an efficient means for selective partial oxidation of NO to NO2. When combined with some types of SCR catalyst, the plasma can greatly enhance the NOx reduction and eliminate some of the deficiencies encountered in an entirely catalyst-based approach.

Download or read book Heavy Duty Emissions Control written by and published by . This book was released on 2003 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt: Progress has been made in the control of combustion processes to limit the formation of environmentally harmful species, but lean burn vehicles, such as those powered by diesel engines used for the majority of commercial trucking and off-road applications, remain a major source of nitrogen oxides (NOx) and particulate matter (PM) emissions. Tighter control of the combustion process coupled with exhaust gas recirculation has brought emissions in line with 2004 targets worldwide. Additional modifications to the engine control system, somewhat limited NOx control, and PM filters will likely allow the 2007 limits to be met for the on-highway regulations for heavy-duty engines in the United States. Concern arises when the NOx emission limit of 0.2 g/bhphr set for the year 2010 is considered.

Download or read book Energy Research Abstracts written by and published by . This book was released on 1993 with total page 654 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma assisted Catalytic Reduction of NO sub x sub written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Many studies suggest that lean-NOx SCR proceeds via oxidation of NO to NO[not] by oxygen, followed by the reaction of the NO[not]with hydrocarbons. On catalysts that are not very effective in catalyzing the equilibration of NO+O[not] and NO[not], the rate of N[not] formation issubstantially higher when the input NOx is NO[not] instead of NO. The apparent bifunctional mechanism in the SCR ofNOx has prompted the use of mechanically mixed catalyst components, in which one component is used to accelerate theoxidation of NO to NO[not], and another component catalyzes the reaction between NO[not] and the hydrocarbon. Catalysts that previously wereregarded as inactive for NOx reduction could therefore become efficient when mixed with an oxidation catalyst. PreconvertingNO to NO[not] opens the opportunity for a wider range of SCR catalysts and perhaps improves the durability of these catalysts. This paperdescribes the use of a non-thermal plasma as an efficient means for selective partial oxidation of NO to NO[not]. When combined with sometypes of SCR catalyst, the plasma can greatly enhance the NOx reduction and eliminate some of the deficiencies encountered inan entirely catalyst-based approach. efficiency for reduction of NOsubx

Download or read book Simultaneous Catalytic Removal of Diesel Soot and Nox written by Wenfeng Shangguan and published by Energy and Environment Researc. This book was released on 2019-07-28 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Photocatalysis Fundamental Processes and Applications written by Mehrorang Ghaedi and published by Academic Press. This book was released on 2021-03-19 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt: Photocatalysis: Fundamental Processes and Applications, Volume 32 in the Interface Science and Technology Series, discusses the fundamental aspects of photocatalysis and its process and applications to the decontamination of wastewater, hydrogen production via water splitting, and photo reduction of carbon dioxide to hydrocarbon. The book discusses the fundamental aspects of all applications together with their proper mechanisms, thus providing essential information for deep research in the area of clean environment and green energy production. Provides background on the fundamental and experimental processes of photocatalysis Covers photocatalysis and its impact on creating a clean environment and energy sources Applies photocatalysis to the decontamination of wastewater, hydrogen production via water splitting, and photo reduction of carbon dioxide to hydrocarbon Edited by a world-leading researcher in interface science

Download or read book Non Thermal Plasma Approach To Simultaneous Removal of NOx Particulate Matter written by and published by . This book was released on 2000 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: Develop predictive performance and plasma chemistry tools for an NTP reactor Insights for reactor optimization and energy efficiency Qualitative screening of reactor design concepts Develop working model to guide reactor design Power requirements and operating parameters Geometry and properties Gap width and thickness, barrier material and thickness, etc Voltage requirements, frequency, space velocity Insights on or resolution of operational issues Diagnosis and interpretation of experiments.

Download or read book IEEE Transactions on Dielectrics and Electrical Insulation written by and published by . This book was released on 2005 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: