Recovery of Farm Waste After Methanization by Evaporation on Inclined Plate

Hiba Zouaghi (1) , Souad Harmand (2) , Sadok Ben Jabrallah

1 National Engineering School of Monastir
2 LAMIH - Laboratoire d'Automatique, de Mécanique et d'Informatique industrielles et Humaines - UMR 8201

This work addresses the recovery of a liquid effluent by thermal evaporation. It is a digestate of pig manure, rich in N, P, and K (Granier 1993; Latimier 1996; Levasseur, Composition et volume de lisier produit par le porc: Données bibliographiques. TECHNI 21(4):16–19, 1998). The effluent was subjected to anaerobic digestion and phase separation by centrifugation. Several recovery scenarios for the liquid phase of a waste with 2.3% DM (Dry Matter) are analyzed. Because of the high consumption of fossil energy in the world, we analyze in this work the evaporation of this effluent using solar energy, in order to concentrate N, P, and K elements. The device consists of a stainless steel plate with a tilt angle of 30° and is not covered with glass. The liquid circulates as a film on the steel plate and is exposed to a 6000-W solar simulator. This work is divided into two primary parts. The first part is the thermophysical characterization of the effluent comparing to water. In the second part, evaporation tests with liquid effluent were performed. So, experimental tests will be valid by determining the equations of heat and mass balances on the plate and on the film (Bouchekima 2001; Chen 1986; Brau, Support de cours de convection pour 3 GCU. Insa de Lyon, département de Génie Civil et Urbanisme, 2006). Before starting the tests, the plate is exposed to solar radiation until stabilization of its temperature. A validation of the temperature of the plate, depending on solar flux and temperature of air, in laminar regime, was performed (Huetz-Aubert, Revue Phys Appl 17:251–260, 1981). We find that when the solar flux increases, the temperature of the plate increases. However, if solar flux is constant, the temperature of the plate decreases when the air temperature increases. The liquid circulates as a film flowing from the top of the plate. Local heat flux measurements, temperatures, and evaporated flow for input flow rate from 1 to 5 g/s are determined and compared with experimental results.

Mots clés: Recovery; Evaporation; Balance; Evaporated flow; Solar flux

Domaines: Matériaux

Hiba Zouaghi, Souad Harmand, Sadok Ben Jabrallah. Recovery of Farm Waste After Methanization by Evaporation on Inclined Plate. Exergy for A Better Environment and Improved Sustainability 2, Springer International Publishing, pp.283-297, 2018, Green Energy and Technology, 978-3-319-62575-1. ⟨10.1007/978-3-319-62575-1_20⟩. ⟨hal-03449956⟩