APPIBio

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.