Study On Nanofiltration Processes Of Sugar Solution

In order to develop the desalination processes in diafiltration mode by NF, a series of experiments of glucose and salt system were conduct respectively by NF. By these experiments the dependence of factors including concentration, pH value and salt types on solute retention and permeate flux were investigated. Based on these experiments datum, desalination model taking into account factors on desalination effect in diafiltration mode was constructed by introduction of mass balance and irreversible thermodynamic model. With the direction of conclusion of simulation model simulation membrane integrated processes were applied to the actual industry systems include potato wastewater treatment and ginger wastewater successfully. In order to solve the problems lied in integration between upstream reaction and NF, the integration model simulation was carried out and the law of integration between reaction and NF was discovered.The experimental study of NF process in neutral organic substance and inorganic salt systems The dependence on solute retention of three factors including solution concentration, pH value and the type of salt was investigated by a sequence of experiments in glucose and salt systems respectively. The results indicated that as the solution concentration increases in glucose as well as sodium chlorine solution, the solute retention of these two solutions both decrease. But the decreasing extent of retention of salt is more than that of glucose. In the Na₂SO₄ and MgSO₄ systems, the further the solution pH value departs from neutral, the less solution retention is. In MgCl₂ solution, the less the solution pH value departs from neutral, the more solution retention is. As to NaCl system, the retention increase as the pH value increase in acid solution and the solute retention of base solution is more than that of acid solution. As long as this nanofiltration membrane was concept, the isoelectric point is near pH=4. The retention sequence of four salts is Na₂SO₄> MgSO₄> NaCl> MgCl₂ by experiments in neutral condition.The mathematic simulation of desalination from glucose solution by nanofiltration In order to solve the problems of bad effect and serious loss of valid component in desalination by diafiltration, the concentrated desalination model as to glucose-NaCl simulation system is established by the mean of mathematicssimulation. The dependence of these four factors including pressure concentration times pH value and different modes on objective function consists of desalination effect , loss ratio of valid component , permeate flux and separation factor were investigated. The result indicate that when the concentration factor 0=1.33, the loss ratio of glucose is the least going on the premise of the same salt concentration. The desalination ratio is better in batch mode than in continual mode. In comparison with constant pressure mode, the separation factor increases 25 percents in variable pressure mode. The separation factor is two times more than that of constant pH mode when the pH of solution is near isoelectric point of membrane. The intrinsical law of concentrated desalination was discovered to direct the experiment research and project design.Application of integrated membrane process on potato wastewater treatment The potato wastewater contains valuable potato protein and oligosaccharides. Its COD value is about 120000mg/L.. The retention of potato protein is 98% by UF membrane and the retention of sugar is 88% by NF membrane. The residual permeated water then reused. With the integrated technologies, both the environmental pollution and the resource utilization may be achieved.Application of integrated membrane process on ginger waste water treatment Current domestic industry of dioscorea zingiberensis produces large quantity of wastewater. This seriously affects the quality of the water source for the national South-to-north Water Displacement Project and from the aspect of environment protection the wastewater treatment should be dealt with as soon as possible. The serial of membranes experiments were carried out by several types of organic membranes and ceramic membranes so as to recover the glucose. The membranes processes dealing with the wastewater were optimized. The glucose solution whose purity is 85%-90% was separated by membranes processes. The COD of wastewater is reduced from 82000mg/L to 4000 mg/L steady.The mathematic simulation of chemical reaction coupled with NF The most of organic synthesis reactions in pharmaceutical and fine industry such as Cyanuric Chloride Reaction System are reversible and the limit of conversation exists. The noble NF membrane reactor can solve these problems. Because the separation of small and big unpolar organic molecular can be realized by NF membrane process, the desirable reaction product of low molecular weight can break away so as to promote the reaction and separate the products from the raw material. The numericalmodeling of this coupling process is established to simulate the process and predict the final results. The dependence of operation mode, as well as the flux of feed is investigated in the article. The results reveal that: the combination of NF membrane process and reactions can increases the conversation, reduce the reaction span and eliminate the subsequent downstream separation steps. It is demonstrated that the NF membrane reactor is promising technology and will play an important role in future.