Conference Dates

March 8-13, 2009

Abstract

A semi-industrial plant of BtL production by biomass gasification is planned to be operating in 2011 in the Northern-East of France by a French Energy Research Centre, called Commissariat à l’Energie Atomique (CEA), and several partners. This demonstration plant will be a 50 MW plant, based on an entrained flow reactor, followed by different stages of syngas cleaning and a final stage of Fischer-Tropsch synthesis.

One study has been launched on the biomass regional resources that may be used as feedstock in the plant. The first task of this study deals with the availability of the resources and their feasibility and cost of supply. This paper is focused on the second task, whose aim is to check the suitability of the potential resources with the process, in order to define which one should be chosen.

A sampling based on several tens samples from the region was first used, both from wood chips from forestry, wood chips from Short Rotation Coppice (SRC) and agricultural raw materials including straw and energy crops. Measurements were done on the main influential properties of biomass, either physical (granulometry, density, moisture), thermal (LHV) or physico-chemical (proximate analysis, elemental composition, particularly in minor elements, ash composition and fusibility).

Results show that there is not much variability in the biomass properties inside the different families (wood chips, agricultural raw materials). The values of most properties fall in the range of the required specifications. However, some properties may be questionable: (i) wood chips granulometry, with too many fine particles (ii) density, which is too low in agricultural products (0.05), (iii) sulphur, fluorine and chlorine contents, which are too high, especially chlorine in agricultural residues (1000-8000 ppm) (iv) other impurities amounts, such as Cr, Cu, Zn, Ni, that are above specifications in some samples (v) ash content, which is slightly too high in SRC (3 wmf%) and too high in most agricultural raw materials (5 wmf%) (vi) ash melting point - whose measurement still needs to be confirmed - but which is apparently too low in most agricultural samples and in some SRC.

Based on these statements, wood chips from forestry appear as the most suitable resource for the process. SRC also seem quite suitable for the process and may be seen as a short-term alternative. Agricultural raw materials are more problematical and may be seen as a short to mid-term option. Therefore, wood chips will be the first resource to be used in the demonstration plant and a complimentary sampling has been recently performed on this kind of feedstock, leading to the adjunction of 60 new samples. These measurements should enable to define more precisely the range of variation of the problematic properties.

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