MULTI APPROACH OF THE IMPACT OF BIOFUELS ON THE POST-TREATMENT EXHAUST GAS SYSTEMS – APPIBio
Judging the poisoning of the exhaust gas treatment catalytic converters when Biodiesel is used in large extent.
A heavy duty exhaust pipe respecting the Euro VI standard is complex and includes a diesel oxidation catalyst (DOC), a catalyst for the NOx selective reduction (SCR), and a diesel particulate filter (DPF), with a required durability of 700 000 km. When biodiesel is used in massive extend, catalysts will be subjected to large amounts of poisons (Na, K, and P, even if they are limited to a few ppm in biodiesel) over 700 000 km. The durability of the catalytic exhaust system is then questionable.
Main issues raised & general objectives: understand and predict the deterioration of the catalytic post-treatment efficiency when bioDiesel is used.
The Appibio project is dedicated to the elementary research that is required for technological advancement in transportation (heavy duty vehicles), with an aim of meeting future emission standards, while also focusing on the reduction of CO2 emissions. In order to meet the Euro VI standard, heavy duty vehicles must be equipped with a post-treatment system that includes a diesel oxidation catalyst (DOC), a NOx selective reduction catalyst (SCR), and a diesel particulate filter (DPF), with a durability objective of 7 years or 700 000 km. Even though biodiesel presents the advantage of being renewable and of limiting the carbon impact of vehicles, the durability of the catalytic processes could be compromised in case of exclusive use of biodiesel (captive-fleet vehicles, buses and trucks). Indeed, in this case the catalysts are subjected to large amounts of Na-, K- and P-based poisons over 700 000 km. This poisoning is an issue of major importance for the actors in this domain, such as Renault Trucks, which intends to commercialise 100% biodiesel approved vehicles until 2020. This topic is therefore complex and multidisciplinary, and the proposed solutions must be economically acceptable. The challenges essentially reside in the comprehension of the involved deactivation mechanisms of the set of catalytic systems and in soot oxidation. It is also necessary to integrate the interactions among the different catalytic units. Impacts of thermal treatments (regeneration or supplementary aging) will be investigated. The data collected will allow Renault Trucks to refine an ageing model for post-treatment systems that takes into account the conditions of use and integrates the use of biofuels. Finally, in the aim of obtaining more resistant catalyst systems that conform to the required standards in terms of effectiveness and durability, each partner will be able to suggest new catalysts that are compatible with the use of these new fuels.
The APPIBio program aims to investigate the effects of biodiesel on the durability of the exhaust gas post-treatment system, taking into account the interactions among the catalytic elements of the post-treatment system. The proposal is divided into two focus areas. The first concerns the study of the deactivation of the Diesel Oxidation catalyst (DOC, for CO and unburned hydrocarbons oxidation) and the NOx reduction catalyst (SCR) through poisoning (Na, K, P). Each poison will be considered individually, and then thereafter studied simultaneously. Also, the influence of specific oxygenated hydrocarbons that emanate from biodiesel combustion will be examined over the DOC. The objective is to assess their intrinsic reactivity, and to determine possible competitions. Special attention will be given to the NO2/NO ratio, which depends mainly on the DOC placed upstream of the other systems, because it is a key parameter involved in both NOx reduction and the passive regeneration of trapped soot. In addition, the behaviour of the poisoned catalysts with respect to heat treatment will be examined (supplementary ageing and/or regeneration). The second focus area will be the specific problem of soot. Today, little information is available about the physics and chemistry of the particles formed when biodiesel is used. The impact on soot reactivity (passive and active regeneration) generated by various biodiesels will be studied in mechanistic and kinetic terms using model and real soot, both of them generated by project partners. The set of results obtained through this project will be added to the global kinetic model internally developed by Renault Trucks to predict the ageing of the post-treatment process. Finally, after the identification of the various effects on the catalytic systems observed with biodiesel use, each partner will be able to propose new catalytic formulations with improved resistance to this new fuel.
Investigations performed during this project regarding the interactions between the three catalytic systems and the components specifically linked to biodiesel use allowed a significant an extension of knowledge.
All public results are available in the 10 scientific publications reported in the «Scientific production« section.
The set of results obtained through this project will be added to the global kinetic model internally developed by Renault Trucks to predict the ageing of the post-treatment process, especially when biodiesel is used.
Additionally, the Appibio project has also enabled developments of new partnerships between the consortium members. For instance, a funding was provided by Renault-Trucks in November 2017 for a PhD position in association with IRCELYON about the aging of the post-treatment systems. Moreover, two service contracts (Renault-Trucks - IRCELYON and Renault-Trucks – IC2MP) have been concluded for the supply of catalyst characterizations.
PUBLICATIONS:
1- Impacts of oxygenated compounds concentration on sooting propensities and soot oxidative reactivity: Application to Diesel and BioDiesel surrogates
Abboud et al., Fuel 193 (2017) 241–253
DOI: 10.1016/j.fuel.2016.12.034
2- Biofuel impact on Diesel engine after-treatment: deactivation mechanisms and soot reactivity.
Iojoiu et al.
Emission Control Science and Technology 4 (2017) 15-32.
DOI: 10.1007/s40825-017-0079-x
3- Impact of bioDiesel impurities on carbon oxidation in passive regeneration conditions: Influence of the alkali metals.
Schobing et al, Applied Catalysis B 226 (2018) 596-607
DOI: 10.1016/j.apcatb.2017.12.011
4- Influence of the sodium impregnation solvent on the deactivation of Cu/FER exchanged zeolites dedicated to the SCR of NOx with NH3.
Tarot et al., Catalysts 8 (2018) 3
DOI: 10.3390/catal8010003
5- Impacts of ester’s carbon chain length and concentration on sootingpropensities and soot oxidative reactivity: Application to Diesel and bioDiesel surrogates
Abboud et al., Fuel 222 (2018) 586-598
DOI: 10.1016/j.fuel.2018.02.103
6- Influence of sodium and/or phosphorus addition on the deactivation of Cu-FER exchanged zeolites for SCR of NOx with NH3.
Tarot et al., Topics in Catalysis (2018)
DOI: 10.1007/s11244-018-1117-9
7- Impact of engine operating cycle, bioDiesel blends and fuel impurities on soot production and soot characteristics
Schobing et al., Combustion and Flame198 (2018) 1–13
DOI: 10.1016/j.combustflame.2018.08.025
8- Effect of Na, K, Ca and P-impurities on diesel oxidation catalysts (DOCs)
Anguita et al., Chemical Engineering Journal 352 (2018) 333-342
DOI: 10.1016/j.cej.2018.07.040
9- Influence of Na, P and (Na+P) poisoning on a model copper-ferrierite NH3-SCR catalyst.
Tarot et al., Applied Catalysis B (2019)
DOI: 10.1016/j.apcatb.2019.03.044
10- Study of hydrothermal aging impact on Na- and P-modified diesel oxidation catalyst (DOC).
Anguita et al., Journal Catal 375 (2019) 329-338
DOI: 10.1016/j.jcat.2019.06.028
The Euro VI regulations for trucks and buses, incoming in 2014, impose an additional abatement of 80% for the NOx emission, and of 66% for particulates, in comparison with the current Euro V standard. It implies to implement a complex exhaust gas post-treatment system including (i) a Diesel Oxidation catalyst (DOC) to treat together unburned hydrocarbons and carbon monoxide, (ii) a catalyst for the NOx selective reduction (SCR), and (iii) a diesel particulate filter (DPF). In addition, the European guideline 2009/33/CE imposes the development of biodiesel to prevent CO2 emission, a powerful green house gas. However, Biodiesel contains alkali metals (Na, K) or phosphorus (P), which are potential poisons for the global post-treatment system. The European norm 14214 fixes at 5 and 10 ppm the maximal contents in alkali and phosphorus, respectively. Besides, the heavy trucks manufacturers have to comply with the present Euro norms for 7 years or 700 000km. Considering these objectives of durability, these Na, K and P contents are not so negligible. Then, an over standards deterioration of the exhaust gases post-treatment system efficiency is quite possible, particularly for heavy vehicles of captive fleets functioning with pure Biodiesel (bus, vehicles for domestic garbage trucks,…). This problematic is a major concern of the manufacturers, notably for Renault Trucks/VOLVO Powertrain. The APPIBio project aims to clearly investigate the effects of bioDiesel on the durability of the three on boarded exhaust gases systems (DOC and SCR catalysts poisoning, specific soots reactivity…), taking into account the interactions between the deteriorations of each element of the post-treatment system.
The project is divided in two main axes. The first one concerns the study of the deactivation of the DOC and SCR catalysts by poisoning (Na, K, P). In first, each poison took individually will be considered, and secondly, they will be studied simultaneously. Besides, the influence of specific oxygenated hydrocarbons, coming from the Biodiesel combustion, will also be examined over the DOC. The objective is to assess for their intrinsic reactivity, and to determine possible competitions, in particular for the oxidation catalyst. Special attention will be given to the NO2/NO ratio, mainly dependent of DOC placed upstream of the other systems, because it is a key parameter involved in both the NOx reduction over the SCR catalyst and the passive regeneration of soot trapped in the DPF. In addition, the behaviours of the poisoned catalysts toward heat treatments will be examined (supplementary aging and/or regeneration?).
The second axis will be focussed on the specific problem of soot. Today, few information are available on the physic and the chemistry of particles formation mechanism when Biodiesel is used. The impact of the poisons on soot reactivity (passive and active regeneration) generated by various biodiesel will be studied in terms of mechanism and kinetic using model and real soot, both generated by the project’s partners.
The whole of results obtained during this project will be added in the global kinetic model, intern to Renault Trucks/VOLVO Powertrain, used to predict the ageing of post-treatment process, in order to anticipate the evolution of the system according to the frequency of use and content of the fuel in Biodiesel.
Finally, after the identification of the different impacts of the use of a biodiesel toward the catalytic systems, each partner will be able to propose new catalytic formulations in order to improve the resistance to the utilization of this new carburant.
To achieve this challenging project, a consortium including five major academic and industrial partners of exhaust gas post-treatment technologies has been constituted to gather all the necessary skills. This consortium is based on a heavyweight manufacturer (Renault Trucks) and four academic laboratories of Paris, Poitiers, Mulhouse and Lyon Universities.
Project coordination
Xavier COURTOIS (Institut de Chimie des Milieux et des Matériaux de Poitiers, Université de Poitiers, UMR 7285)
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partner
LGRE Laboratoire de Gestion des Risques et Environnement, Université de Haute Alsace, EA2334
Renault Trucks Renault Trucks
IRCELYON - CNRS Institut de Recherches sur la Catalyse et l'Environnement, Université Claude Bernard Lyon I, UMR 5256
IJLRA INSTITUT JEAN LE ROND D'ALEMBERT, UPMC, UMR 7190
IC2MP Institut de Chimie des Milieux et des Matériaux de Poitiers, Université de Poitiers, UMR 7285
Help of the ANR 1,001,800 euros
Beginning and duration of the scientific project:
September 2014
- 42 Months
