Non-thermal Plasma Exhaust Aftertreatment PDF Download

Author: J. H. Whealton
Publisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 14

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Author:
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ISBN:
Category :
Languages : en
Pages : 10

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The trend in environmental legislation is such that primary engine modifications will not be sufficient to meet all future emissions requirements and exhaust aftertreatment technologies will need to be employed. One potential solution that is well placed to meet those requirements is non-thermal plasma technology. This paper will describe our work with some of our partners in the development of a plasma based diesel particulate filter (DPF) and plasma assisted catalytic reduction (PACR) for NOx removal. This paper describes the development of non-thermal plasma technology for the aftertreatment of particulates from a passenger car engine and NOx from a marine diesel exhaust application.

Author: Scott T. Eakle
Publisher:
ISBN:
Category : Motor vehicles
Languages : en
Pages : 304

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Author:
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ISBN:
Category :
Languages : en
Pages :

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There is a need for an efficient, durable technology to reduce NOx emissions from oxidative exhaust streams such as those produced by compression-ignition, direct injection (CIDI) diesel or lean-burn gasoline engines. A partnership formed between the DOE Office of Advanced Automotive Technology, Pacific Northwest National Laboratory, Oak Ridge National Laboratory and the USCAR Low Emission Technologies Research and Development Partnership is evaluating the effectiveness of a non-thermal plasma in conjunction with catalytic materials to mediate NOx and particulate emissions from diesel fueled light duty (CIDI) engines. Preliminary studies showed that plasma-catalyst systems could reduce up to 70% of NOx emissions at an equivalent cost of 3.5% of the input fuel in simulated diesel exhaust. These studies also showed that the type and concentration of hydrocarbon play a key role in both the plasma gas phase chemistry and the catalyst surface chemistry. More recently, plasma/catalyst systems have been evaluated for NOx reduction and particulate removal on a CIDI engine. Performance results for select plasma-catalyst systems for both simulated and actual CIDI exhaust will be presented. The effect of NOx and hydrocarbon concentration on plasma-catalyst performance will also be shown. SAE Paper SAE-2000-01-1601 {copyright} 2000 SAE International. This paper is published on this website with permission from SAE International. As a user of this website, you are permitted to view this paper on-line, download this pdf file and print one copy of this paper at no cost for your use only. The downloaded pdf file and printout of this SAE paper may not be copied, distributed or forwarded to others or for the use of others.

Author:
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ISBN:
Category :
Languages : en
Pages : 12

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There are four post combustion (nonthermal) plasma treatments on the table for reducing NOx in exhaust streams. This paper compares these techniques and suggests what appears to be a novel (8 inventions) and optimum path for development of auseful ehaust treatment system. We propose to use 5 GHz microwaves which will have a risetime of 20 ps, 100 times shorter than present state of the art and result in the best chemistry path by reduction ofplasma shielding, greater availability of atomic nitrogen, elimination of surface charging of dielectrics, avoidance of low threshold fields, and higher breakdown limit. We also propose combining a surface intrinsically into the plasma discharge. Novel embodiments are proposed for the pebbel bed discharge allowing an order of amgnitude increase of eidl-volume over the closest packing configuration.

Author:
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ISBN:
Category :
Languages : en
Pages : 9

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The ultimate objective of this work has been to develop a nonthermal plasma process to reduce NO(subscript x) in diesel exhaust gas. A secondary objective has been to study the possibility of particulate matter (soot) reduction by the same technique. The early work revealed a fundamental difficulty with this NO(subscript x) reduction approach in the gas environment of the diesel engine exhaust. These observations necessitated a thorough study of the unfavorable chemistry in the hope that knowledge of the chemical mechanism would offer an opportunity to make the approach useful for NO(subscript x) reduction. Whereas fundamental understanding of the mechanism has been obtained, the authors have not found any measure that would make the approach meet its original objective.

Author:
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ISBN:
Category :
Languages : en
Pages : 7

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Modern diesel passenger vehicles employing common rail, high speed direct injection engines are capable of matching the drivability of gasoline powered vehicles with the additional benefit of providing high torque at low engine speed [1]. The diesel engine also offers considerable fuel economy and CO2 emissions advantages. However, future emissions standards [2,3] present a significant challenge for the diesel engine, as its lean exhaust precludes the use of aftertreatment strategies employing 3- way catalytic converters, which operate under stoichiometric conditions. In recent years significant developments by diesel engine manufacturers have greatly reduced emissions of both particulates (PM) and oxides of nitrogen (NOx) [4,5]. However to achieve compliance with future legislative limits it has been suggested that an integrated approach involving a combination of engine modifications and aftertreatment technology [1] will be required. A relatively new approach to exhaust aftertreatment is the application of non-thermal plasma (NTP) or plasma catalyst hybrid systems. These have the potential for treatment of both NOx and PM emissions [6- 8]. The primary focus of recent plasma aftertreatment studies [9-12] has concentrated on the removal of NOx. It has been shown that by combining plasmas with catalysts it is possible to chemically reduce NOx. The most common approach is to use a 2- stage system relying upon the plasma oxidation of hydrocarbons to promote NO to NO2 conversion as a precursor to NO2 reduction over a catalyst. However, relatively little work has yet been published on the oxidation of PM by plasma [8,13]. Previous investigations [8] have reported that a suitably designed NTP reactor containing a packing material designed to filter and retain PM can effect the oxidation of PM in diesel exhausts at low temperatures. It has been suggested that the retained PM competes with hydrocarbons for O, and possibly OH, radicals. This is an important consideration in plasma - catalyst hybrid schemes for the removal of NOx employing an NO2 selective catalyst, as the oxidation of PM may deplete the key radicals necessary for NO to NO2 conversion. It was also suggested that where simultaneous NOx and PM removal are required, alternative catalyst formulations may be needed which may be selective to NO rather than NO2.

Author: James Shawcross
Publisher:
ISBN:
Category :
Languages : en
Pages : 257

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Author: Cheng Chen
Publisher:
ISBN:
Category : Atmospheric electricity
Languages : en
Pages : 242

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"There is a growing demand for energy usage in the world, primarily due to increasing economic activity. This need can be met by pursuing increased power generation. However the impact of emissions from power generation sources on the health of human beings and environmental continues to be a major concern. In order to maintain and enhance environmental quality there is a need for the development of clean energy products. A diesel aftertreatment device was developed at RIT to reduce particulate matter (PM) in the emissions of generators and diesel engines by using the combination of non-thermal plasma oxidation and emission catalyst technologies. The non-thermal plasma (corona discharge) created by a high voltage electrode produces ionized gas or plasma in the charging section of the device. Simultaneously gas atoms are excited, producing highly reactive O, OH, and NO2 radicals. These radicals oxidize PM to gaseous products including CO, and CO2. The device has a low pressure drop compared with other diesel aftertreatment devices since it self-regenerates and there is no accumulation of PM in the system. The scope of this thesis is to develop a numerical model to simulate the performance of this diesel aftertreatment device. The model calculates the diesel exhaust conditions, plasma generation condition, electric field, power consumption, particulate collection, and particle removal. The model results agree with the experimental data, which proves that the model can be used for system performance prediction. Based on keeping the same PM removal efficiency and back pressure effects on diesel engine, a method was developed for system scale-up or scale-down"--Abstract.

Author:
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Category :
Languages : en
Pages :

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A method for non-thermal plasma aftertreatment of exhaust gases the method comprising the steps of providing short risetime, high frequency, high power bursts of low-duty factor microwaves sufficient to generate a plasma discharge and passing a gas to be treated through the discharge so as to cause dissociative reduction of the exhaust gases and enhanced catalyst reactivity through application of the pulsed microwave fields directly to the catalyst material sufficient to cause a polarizability catastrophe and enhanced heating of the metal crystallite particles of the catalyst, and in the presence or absence of the plasma. The invention also includes a reactor for aftertreatment of exhaust gases.