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Rhéologie des résidus agricoles pour un procédé multi-étapes de méthanisation en voie sèche

Abstract : The Arkometha® process uses biogas injections to mix agricultural residues (manure, slurry, silage, straw) in a dry anaerobic digestion process. Knowledge of the rheological properties of these materials, rarely studied in the literature, and especially not on an industrial scale, is an essential element to supervise and control the mixing process. This thesis aims to improve the understanding of the physical and rheological evolutions of these materials along the anaerobic digestion process. The literature showed the need for a rheometer able to measure the rheological properties of these products at the industrial scale. For this purpose, specifications were established based on the scientific and technical constraints imposed by these materials, which are considered as fiber concentrated suspensions. On this basis, a large rheometer for substrates, called RGDS for (Rheometer Grand Dimensions for the Substrate), was built, validated and commissioned on an industrial site. The van test technique was used to measure the yield stress and mixer blades, calibrated using the Couette analogy, were used to measure shear stresses. In the third chapter we have shown the utilization limits of the total solids (TS%), traditionally used as the main parameter for rheology controlling. In this chapter we treated the yield stress of these materials as a rheological parameter example. We have shown that it is more appropriate to control the water distribution in order to control the rheological properties of theses suspensions by taking into account the spongy nature of the lignocellulosic material. We have shown how to determine the critical concentrations separating the semi-concentrated, concentrated, triphasic and the wet granular behaviors and their relationship with yield stress. In the fourth chapter, we studied the effect of changes in the anaerobic digestion operating parameters, such as fiber size, temperature and TS on the rheological properties of materials. Several models and empirical equations have been proposed to quantify the advantage of making changes in the operating parameters on the rheology of these materials.
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Submitted on : Tuesday, October 8, 2019 - 3:12:11 PM
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  • HAL Id : tel-02308463, version 1




Victor Ruys. Rhéologie des résidus agricoles pour un procédé multi-étapes de méthanisation en voie sèche. Sciences agricoles. Université Grenoble Alpes, 2017. Français. ⟨NNT : 2017GREAI064⟩. ⟨tel-02308463⟩



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