Influence Of Dissolved Oxygen On Process Of Juice Clarification

The purification and separation of mixed juice is one of the most difficult and costful working procedure. It has direct relation to latter procedure and play a crucial role on quality of sugar and recovery of sugar. The clarification process of mixed juice is an important step in sugar-refining process. Oxygen from air enter into the juice through various paths, and there are few reports about the influence of dissolved oxygen on process of the juice clarification.In this thesis, the influence of dissolved oxygen on process of juice clarification was systemic studied so as to control production and reduce disadvantageous factors in sugar-refining process. The following aspects were investigated:1. The oxygenation reaction of sulfurous acid induced by dissolved oxygen in clarification process was investigated. The results indicate that rate of oxygenation reaction slow down as concentration of sucrose increased. Rise of temperature and pH value, increased concentration of SO₃^2- can promote the rate of oxygenation reaction.2. The variety of colour on condition of coexistence of dissolved oxygen,hydroxybenzene and Fe ion was also investigated. The results indicate that the rate of catalyze oxidation reaction of hydroxybenzene enzyme accelerate when concentration of sucrose increased. Sulfur dioxide can depress the reaction.3. The degradation situation of PAM aqueous solution induced by dissolved oxygen in clarification process was investigated. The results indicate that soluble oxygen can promote the degradation of polyacrylamide obviously at high temperature.4. The influence of dissolved oxygen on process of juice clarification was investigated. The mixed juice contained different amount of dissolved oxygen by aeration. Six factors including purity, colour, sedimentation velocity, filtration velocity, concentration of calcium content and sulfate radical content were investigated through orthogonal experiments. Range analysis and Variance analysis from experimental results were made to confirm influenced extent of dissolved oxygen in clarification process.5. The methods of eliminating oxygen were also investigated. The general methods of eliminating oxygen including physical method and chemical method. The results indicate that vacuum eliminating oxygen can play an effective role for physical method, rate of eliminating oxygen using sodium sulfite is larger than using vitamine C.