Periodic Report Summary - LOWCAFF (Low Carbon Future Fuels) Project contextThe understanding of knock phenomena in spark ignition engines, the modelling of the formation of soot in diesel engines, the reduction of the emission of pollutants (CO, NOx, acrolein, etc.), and the development of new engines (homogenous charge compression ignition) have led to an increasing need for the development of detailed chemical kinetic models. In this context, the project aims to develop accurate kinetic mechanisms of surrogate fuels that can, ideally, predict well the ignition delay time, laminar flame speed, fuel conversion, intermediate species concentration, negative temperature coefficient, cool flame region observed during the oxidation of diesel and gasoline fuels. Software called EXGAS (detailed kinetic models generator developed at CNRS, Nancy, France) will be used to generate kinetic mechanisms. The system is a made of three parts: (i) reaction base: including all the reactions involving C0-C2 radicals and molecules; (ii) comprehensive primary mechanism: where the only molecular reactants considered are the initial organic compounds and oxygen; (iii) lumped secondary mechanism: containing reactions consuming the molecular products of the primary mechanism, which do not react in the reaction bases.Automatic generation system of chemical kinetic models: so far, a detailed bibliographical review of the kinetic study of the primary reference fuels (n-heptane and iso-octane) has been done. This constitutes an experimental database for the validation of the kinetic models. Also, we have assessed the accuracy of some important kinetic models by simulating the experimental results available in the literature. Additional experimental work will be performed in Nancy to cover wider conditions. Furthermore, a presentation abstract, on an investigation of the influence of a cetane-improver - namely 2-ethyl hexyl nitrate - on the behaviour of a diesel surrogate fuel, has been submitted at the Mathematics and Chemical Kinetics in Engineering Conference hosted in India, February 2013. At the end of this project, better predictive detailed chemical kinetic models of surrogate fuels will be developed. The use of those models will allow a more accurate understanding as well as a better control of the fuel combustion in direct injection spark ignition (DISI) engines. As a consequence, the adequacy fuel/engine will have a positive environmental impact (reduction of pollutants) and a greater independence of fossil fuels.Project objectivesThis project aims to develop a novel method using dynamic system modelling approaches to perform consequential life-cycle analysis (CLCA) of biofuels by considering economic, environmental and social perspectives. In this model, attributional life-cycle analysis (ALCA) will be linked with CLCA by introducing several parameters, such as time, technology and energy policy in scenarios study.Project workA comprehensive literature review has been performed. Based on this, a framework of the dynamic system model using sugar cane bioethanol as an example has been established. The change in projected biofuel demand in different scenarios will affect sugar cane bioethanol production and use, which will further cause direct and indirect land-use change. All this will have an effect on greenhouse gas (GHG) emissions. An ALCA of sugar cane bioethanol has been conducted in order to assess these GHG emissions.Project resultsThe production of sugar cane bioethanol has been modelled using chemical process simulation software AspenPlus® to generate mass and energy balance. Based on these, a well-to-wheel ALCA was performed to report direct GHG emissions and energy ratio for sugar cane bioethanol. There are now a significant number of advanced combustion variations that provide lower engine-out emission, especially NOX and particulate matter (PM), lower fuel consumption and stable engine operation over a wide load range. Because of these potential benefits, it was decided to investigate more completely the partially premixed compression ignition combustion concept, specifically to determine whether an engine could operate successfully in CI mode on gasoline and diesel mixtures. For the project period, PCCI is run with much simpler hardware than in a diesel engine and on 13 different research octane number (RON) fuels under 7 test conditions and the study was completed to analyse critical engine and fuel parameters and to judge what speed/load range might be feasible for the PCCI combustion concept. The major strength of the proposed concept is that the fuel economy of a diesel engine or better can be expected from an engine burning gasoline type fuels. It also targets, on one hand, rectifying the diesel/gasoline imbalance and, on the other, reducing engine-out emissions. However, cold starting and very low load operation are most challenging in this concept.Another aim of the project is to explore and test the long-term carbon sequestration potential of biochar (BC) in soil in order to reduce the greenhouse gasses (GHGs) balance of biofuel production. Three main experiments have been set up and carried out: i) a laboratory incubation of BC and soils to assess the short-term stability of BC in soil as affected by production conditions, physical/chemical characteristics and incubation temperature; ii) a field experiment in a commercial Miscanthus plantation in order to assess the impact of BC application rate on GHG emissions, soil temperature and moisture, leaching to groundwater and ecosystem health; and iii) a greenhouse experiment on pot-grown wheat to assess BC type and application rate effect on plant physiology and productivity, leaching to groundwater and GHGs emissions. To date, the main results are that Biochar-derived GHG emissions were significantly lower than those from original biomass feedstock and correlated to BC production conditions. Its field application improved soil structure and did not increase soil CO2 emissions, resulting in a net carbon sink. In the greenhouse, BC did not negatively affect plant productivity and GHGs emissions, and an interaction with rhizosphere carbon cycling was found. The expected final results and their potential impact and use: the addition of Biochar increased carbon stocks in agricultural soils, without decreasing productivity or negatively affecting health and functionality of the agro-ecosystem. Its utilisation could potentially offer a very powerful tool to offset C02 emissions.
