Achim Karl-Erich Heibel

Gas and liquid phase distribution and their effect on reactor performance in the monolith film flow reactor

Nuclear magnetic resonance imaging (MRI) has been applied to study the phase distribution in the monolith film flow reactor. The accumulation of the liquid in the corners of the square channel with an arc-shaped gas–liquid interface has been determined. The average liquid saturation is in good agreement with model calculations. Non-uniformities of the liquid distribution over the four corners of the square channel were apparent, besides the maldistribution over the cross-section of the monolith. Computational fluid dynamics (CFD) calculations applying the measured liquid distribution predict a broadening of the residence time distribution and a shorter break-through time, due to the maldistribution, which is in very good agreement with experimental results. The impact on the modeled gas–liquid mass transfer performance seems to be negligible, due to the nearly linear relation between kGLaV and uLs.

Regeneration Strategies for an Enhanced Thermal Management of Oxide Diesel Particulate Filters

Diesel particulate filters are expected to be used on most passenger car applications designed to meet coming European emission standards, EU5 and EU6. Similar expectations hold for systems designed to meet US Tier 2 Bin 5 standards. Among the various products oxide filter materials, such as cordierite and aluminum titanate, are gaining growing interest due to their unique properties. Besides the intrinsic robustness of the filter products a well designed operating strategy is required for the successful use of filters. The operating strategy is comprised of two elements: the soot estimation and the regeneration strategy. In this paper the second element is discussed in detail by means of theoretical considerations as well as dedicated engine bench experiments. The impact the key operating variables, soot load, exhaust mass flow, oxygen content and temperature, have on the conditions inside the filter are discussed. Their practical relevance and the ability to use them for control purposes is analyzed. Guidelines are presented that should be considered when applying oxide diesel particulate filters. The differences between oxides and materials with higher thermal conductivity are discussed with respect to the relationship between regeneration conditions and the achievable regeneration efficiency. Experimental data show benefits for oxide materials vs. SiC, expected to come from their low conductivity. For the regeneration strategy a simple approach is proposed and illustrated by means of examples. The benefits of a staged regeneration approach are discussed, using two temperature levels during the regeneration.

Improved Lifetime Pressure Drop Management for Robust Cordierite (RC) Filters with Asymmetric Cell Technology (ACT)

The stricter emissions legislation in the US, require the implementation of Diesel Particulate Filters (DPF) for Heavy Duty Diesel engines to meet the 2007 PM emissions targets. Cordierite based wall-flow filters with high filtration efficiency, low p and good thermal durability are the product of choice for these applications. Continuous passive oxidation of the soot by NO2 is desired, however under certain operating and ambient conditions periodic active oxidation of the soot at elevated temperatures (>550oC) is required. A part of the PM emissions of the engine contains noncombustible contributions (ashes). These materials accumulate in the filter over lifetime, resulting in an increase in pressure drop as well as a reduction of the filter volume available for soot accumulation. As the pressure drop rises above manageable levels from a performance perspective, ash cleaning of the filter is required. The ash storage capacity of the filter determines the service interval for the filter. Long service intervals are desired by the end customer. To mitigate the impact of the ash accumulation in the filter, Corning Incorporated has developed filters with the proprietary asymmetric cell technology (ACT), providing high ash capacity with good strength attributes. These filters have larger inlet and smaller outlet channels and therefore a higher volume available for ash storage. The present work summarizes the results of on-engine (HD) ash testing on uncoated Robust Cordierite (RC) filters – O267mmX305mm (O10.5”x12”) in both Standard (200/19) and ACT (270/16) design configurations. The work demonstrates, for an equal size filter a 30% improved ash storage capacity and therefore longer service interval for the ACT design over the standard filter. Good durability of the filters for a long operation timeframe (up to 2700h) was demonstrated. Furthermore the paper summarizes a wide set of post testing evaluations, both non-destructive and destructive to understand the ash distribution and interactions in the filter. INTRODUCTION Due to their high efficiency, excellent power output and good durability aspects diesel engines have been selected as the most attractive propulsion system in key sectors of the economy. With the increase in fuel costs and further improvements in diesel engine technology the expansion of diesel engine technology in other application segments is anticipated. On the other hand the ever tightening emissions regulations require significant reduction in the tailpipe emissions. For example the US HDD on road emissions legislation requires 90% reduction in PM emissions by 2007(relative to 2006 PM limits) and 80% reduction in NOx by 2010 (relative to 2009 NOx limits). The lower emissions are achieved by improvements in engine technology and the use of advanced emissions technologies. Diesel Particulate filters are required for achieving the low PM emissions levels to meet the 2007 US on-road regulations. It is expected that the 2010 NOx limits will be achieved by further advancements in engine technology, improved controls and implementation of DeNOx technology in the form of Selective Catalytic Reduction (SCR) system or Lean NOx Traps (LNT) or a combination of both. Cordierite wall flow monoliths have emerged as the choice of the industry for use as diesel particulate filters (DPFs) due to their compactness and robust design. The design of diesel particulate emissions systems requires balancing of various competing constraints. On the one hand the soot capacity of the filter needs to be sufficiently high to enable the desired regeneration intervals. The soot capacity is driven by the filter volume, the regeneration conditions and control strategy. On the other hand engine back pressure needs to be managed. This includes management of clean and life-time pressure drop for optimized performance of the engine. Corning’s Robust Cordierite (RC) material was developed for medium and heavy duty OEMs and retrofit applications. It provides good soot loading capacity, low pressure drop and excellent durability and strength. 2007-01-0920 Improved Lifetime Pressure Drop Management for Robust Cordierite (RC) Filters with Asymmetric Cell Technology (ACT) Krishna Aravelli and Achim Heibel Corning Incorporated, Diesel Technologies Development

A monolith loop reactor as an attractive alternative to slurry reactors

A new reactor concept to replace slurry bed catalysts with monolithic catalysts is described. Different configurations are presented, all requiring minimal hardware modifications for revamp. One key feature of the new concept is that no troublesome filtration step is required, while maintaining the benefits of high catalyst effectiveness and selectivity. Furthermore, higher catalyst loads per reactor volume can be achieved with the monolith. Cold flow experiments are used to demonstrate the feasibility of the concept and to determine some empirical parameters for a simple hydrodynamic model. Characteristic performance data for the monolith reactor, such as mass transfer, heat transfer, and reactive performance, as well as their dependence on the type of monolith used are discussed on the basis of model calculations.

A Next Generation Cordierite Diesel Particle Filter with Significantly Reduced Pressure Drop

Diesel particle filters (DPF) have become a standard after treatment component for all current and future on-road diesel engines used in the US. In Europe the introduction of EUVI is expected to also result in the broad implementation of DPF’s. The anticipated general trend in engine technology towards higher engine out NOx/PM ratios results in a somewhat changing set of boundary conditions for the DPF predominantly enabling passive regeneration of the DPF. This enables the design of a novel filter concept optimized for low pressure drop, low thermal mass for optimized regeneration and fast heat-up of a downstream SCR system, therefore reducing CO 2 implications for the DPF operation. In this paper we will discuss results from a next generation cordierite DPF designed to address these future needs. The new materials are based on a thinwall design with optimized material and microstructure, resulting in an almost linear pressure drop response with soot loading in the bare and catalyzed state. A significant reduction in soot loaded pressure drop for uncoated and coated filters is demonstrated of the new filter design vs. current EPA 2010 filter technologies. The optimized microstructure also enables high filtration efficiency for mass and number. Results from a wide range of regeneration experiments will be used to discuss the thermal operating window of the new material and the thermal response during normal operation and active regeneration. A uniform temperature distribution and the fast thermal response of the low mass filter minimize implications on fuel consumption.

Untersuchung der Eigenschaften neuer Dieselpartikelfilter

Eine neue Generation von Dieselpartikelfiltern basierend auf einer Aluminiumtitanat-Keramik ist von Corning entwickelt worden. Die neuen DuraTrap-AT-Filter verfugen uber eine extrem hohe Bestandigkeit gegenuber thermischen Spannungen, kombiniert mit einer hohen volumetrischen Warmespeicherfahigkeit. In dem vorliegenden Beitrag werden experimentelle Ergebnisse diskutiert, die mit dem neuen Material in Laborversuchen, am Motorprufstand und in Fahrzeugtests ermittelt wurden.

Technical paths to emission regulation compliance of commercial vehicles in the next decade based upon solutions for EPA 2007 and EU V

During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.

Technische Lösungswege zur Einhaltung der Grenzwerte für Nutzfahrzeugemissionen der nächsten Dekade basierend auf EPA 2007 und EU V

During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.

Technical paths to emission regulation compliance of commercial vehicles in the next decade based upon solutions for EPA 2007 and EU V@@@Technische Lösungswege zur Einhaltung der Grenzwerte für Nutzfahrzeugemissionen der nächsten Dekade basierend auf EPA 2007 und EU V

During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.During the past years significant regulatory reductions of allowable diesel particulate (“PM”) and Nitrogen oxides (“NOx”) emissions have been enacted worldwide. The regionally diverse regulatory requirements have led to different emissions control solutions in Europe (predominantly SCR systems), Japan and USA (predominantly DPF systems). Within Europe, different manufacturers are also using systems with diesel oxidation catalyst (DOC) or open or so-called partial flow filters tailpipe emission reduction. An overview by Corning Incorporated.

Loesungen zur Einhaltung der Grenzwerte fuer Nutzfahrzeugemissionen der naechsten Dekade basierend auf EPA 2007 und EU V

Wahrend der letzten Jahre wurden die gesetzlich erlaubten Emissionen von Diesel-Partikeln („PM“) und Stickoxiden („NOx“) weltweit signifikant reduziert. Die regional unterschiedlichen Emissionsgrenzwerte haben zu verschiedenen Losungen zur Dieselabgasnachbehandlung in Europa (uberwiegend SCR-Systeme), Japan und USA (uberwiegend DPF-Systeme) gefuhrt. Innerhalb Europas haben einige Hersteller auch Systeme mit Dieseloxidationskatalysatoren (DOC) und offenen oder sogenannten Teilstromfiltern zur Emissionsreduzierung eingesetzt. Ein Ubersichtsbeitrag von Corning Incorporated.