Search Results

The aim of the study is to evaluate the possible vanadium emissions from different commercially available vanadium-based SCR monoliths. The vanadium sublimation was studied at laboratory scale using a monolith sample (16 mm diameter × 19 mm long). Vanadia vapors were disposed on an alumina bed placed downstream the catalyst sample, in the hot zone of a furnace. Experiments were carried out with a space velocity of 42 000 h−1. The reactive gas flow was composed of 5%O2, 5%H2O, 500ppm NO and 500ppm NH3. Catalyst samples and alumina bed were exposed to this reactive gas flow during 10 hours at 500°C, 600°C, 650°C, 675°C, 700°C and 750°C, successively. After each test, alumina samples were mineralized from HNO3, HF and HCl mixture. The digests were then diluted with high purity water prior, to ICP-MS analysis. The results revealed that, for full body type catalysts, sublimation of vanadium increases in a significant way from an exposure to the reactive gas flow at 675°C.

We present an experimental and modelling methodology developed at LGRE research laboratory to characterize soot oxidation in the presence of different atmospheres (NO2, NO2/O2), simulating passive regeneration which occur in a Diesel Particulate Filter (DPF). Based on this methodology which aims at deriving the kinetic parameters for soot combustion, the thermal reactivity of different soot has been studied and compared. Soot were produced from a prototype Liebherr engine and on an engine dynamometer at R&D Moteurs company, under two engine cycles and for two different fuels. Small soot masses (15-30mg) were deposited on the quartz frit of the reactor and submitted to a gas flow (NO2 or NO2/O2), under different temperatures. The mole fractions of NO2, NO, CO2 and CO at the reactor outflow were measured by infrared analyzers. The soot oxidation rate and the sample remaining mass were deduced from CO/CO2 emissions.

The current legislation for industrial applications and construction equipment including earthmoving machines and crane engines allows different strategies to fulfill the corresponding exhaust emission limits. Liebherr Machines Bulle SA developed their engines to accomplish these limits using SCRonly technology. IAV supported this development, carrying out engine as well as SCR aftertreatment system and vehicle calibration work including the OBD and NOx Control System (NCS) calibration, as well as executing the homologation procedures at the IAV development center. The engines are used in various Liebherr applications certified for EU Stage IIIb, EPA TIER 4i, China GB4 and IMO MARPOL Tier II according to the regulations “97/68/EC”, “40 CFR Part 1039”, “GB17691-2005” and “40 CFR Parts 9, 85, et al.” using the same SCR hardware for all engine power variants of the corresponding I6 and V8 engine families.