Evaporation Experimental Study of Liquid Effluent after Methanation
Résumé
Pig manure rich in nitrogen, potassium and phosphorus was subjected to anaerobic digestion and phase separation via centrifugation. Several recovery scenarios for the liquid phase of a waste with 2.3% DM (Dry Matter) are analyzed in this paper. The physico-chemical characterization of the effluent is used to justify the use of solar energy in the drying process. The results of an experimental study of the drying kinetics of the effluent using infrared radiation-based drying indicate that evaporated mass flow increases with the increase of heat flux. Several evaporation tests were performed in the laboratory using a solar simulator. The device consists of a stainless steel plate with a tilt angle of 30° that is covered with transparent glass. The liquid circulates as a film on the steel plate and is exposed to a 6000Watt solar simulator. The measured inlet mass flow varied from 0.53 to 1.29g/s.m². The local heat flux measurements, the temperatures and the effluent and water evaporated flow rates are recorded and compared. The measurements indicate that a greater inlet flow results in a lower evaporated flow. The results also demonstrate that preheating the liquid significantly improves the evaporated flow. Comparing drying with and without the cover glass indicates that glass cover ameliorates evaporation and reduces convection heat losses