Environmental friendly method in the sugar-beet production for the colourants removal

Abstract

Despite the fact that the sugar industry is one of the causes of the environmental pollution, not enough has been done on its improvement. According to CEFS, specific energy consumption was 31.49 kWh/100 kg sugar beet. While the overall water used is about 15 m³/t sugar beet processed, the consumption of fresh water is 0.25 – 0.4 m³/t sugar beet processed, or even less in modern sugar factories. The separation operation deserves special attention because of its significant consumption of water end energy. Ultrafiltration could be one of the solutions for energy saving and more effective separation of coloured compounds (which during the crystallisation build into the sucrose crystals) from intermediate products from which sucrose directly crystallises. The aim of this experimental work is to determine the influence of operating parameters on the efficiency on coloured matter removal in high concentrated syrup. In this work syrup solution, which is an intermediate product in the phase of sucrose crystallisation, with 60% dry matter content, is the main feed. Experimental investigations were performed on 20 nm ceramic tubular membrane. Effects of colour removal on syrup solution are investigated at 60 and 80 ºC, in the range of transmembrane pressure between 4 and 10 bars. Optimal values of flow rates are chosen between 100 and 400 L/h. For defining the effects of the membrane separation process, permeate flux are determined. According to mentioned conditions colour is by 35 - 40 % in average, and turbidity is by 80% in average lower according to the feed. The permeate flux could be reached is 45 L/m²h at flow rate 400 L/h and at 80 ºC.