Preliminary Research Of Roll Ultrafiltration Membranes Used In The Purification Of Refining Syrup

Refined sugar is popular in the market, widely used in high-end food sweeteners, has broad market prospects. At present, the decoloring method of refined sugar mill requires a large amount of investment and operation cost, and it will cause serious environmental pollution.In this study, the volume type ultrafiltration membrane filtration will be used to refine syrup to achieve the effect of decolorization and purification.Using ultraviolet visible light wavelength and nanometer particle size analysis to explore the types and content of impurities in refining syrup.Research on various factors by refining syrup ultrafiltration clarification effect.Determine the optimum process conditions.Selected the best membrane cleaning solution.Obtain a new refining sugar syrup decolorization process, Provide the basis for the application of ultrafiltration technology in the refining sugar to clarify. The main research contents and results are as follows.1、The preliminary analysis of the nature and content of the refining sugar syrup is carried on by ultraviolet visible spectroscopy and nanometer particle size analysis, the results are as follows:the main pigments impurities in the refining syrup are the relatively smaller molecular weight impurities, and the particles that is between 4 nm～8 nm account for more than 99% of the total impurity particles.2、Comparing different intercept molecular weight type ultrafiltration membranes (1000 u,2500 u,5000 u) decolorization of refined syrup clarification effect, through the ultrafiltration through the difference of the purity of liquid and decolorization rate, membrane through the fluid flow, in addition to the rate of turbidity, viscosity index and ultraviolet-visible spectra analysis, such as screening suitable ultrafiltration membrane. The results showed that 2500 u have higher membrane ultrafiltration membrane through the liquid flow rate, and good decoloring effect of removing impurity and certain purification effect, the viscosity of syrup become lower after ultrafiltration. Also the indicators can reach the requirement of the production of refined sugar. So choose to adopt intercept molecular weight is 2500 u volume type ultrafiltration membrane ultrafiltration clarification refining sugar syrup.3、The decoloring rate and purity, ultrafiltration through flow rate actting as an index, single factor and orthogonal experiment were conducted to explore the ultrafiltration effect in different recovery rate, operation pressure and raw material of hammer degrees syrup. The optimum process conditions are as follows:Pressure is 2.3 MPa; the recovery is 70% degree of hammer 50 °x. Under the condition of the clearing syrup, diffence of purity increased by 0.45%, the color value dropped by 54.73%, the flow rate was 3.18 L·h-1·m-2.4、The experimental analysis indicates that the main reason caused membrane through the liquid flow attenuation is the attenuation syrup concentration caused by impurity concentration polarization and gel polarization. Exploring the tube cavity flushing of physical cleaning methods and NaOH solution cleaning of chemical cleaning method of uf membrane cleaning effect, The best cleaning solution was selected.It is as follows:When the flow rate of ultrafiltration is 15% lower than the original, a set of lumen was putted to use, every flush for 10 s, repeat 5 times for a group. When the tube cavity was flushed through and the liquid flow back to the original below 85%, chemical cleaning was carried out. Before the chemical cleaning,30℃～35℃ hot water was used to wash equipment for 10 min. Then using the NaOH solution pH of 10, under the temperature of 35℃, this cleaning countined in cycle for 30min (First clean 10 min, then soak 10 min, and then washed for 10 min). Finally, equipment was washed with 30℃～35℃hot water for 10 min. After cleaning the pure water flux recovery rate was over 98%.5、Citing a refining sugar mill with daily processing one thousand tons of raw sugar as an example, ultrafiltration system equipment investment cost is 22.88 million yuan; the installation fee is 2.288 million yuan, amounted to 25.168 million yuan. The system operating cost is 8.622 yuan per tons of raw sugar. Processing raw sugar increased 86.378 yuan per ton, a total investment payback period is 292 production date. Ultrafiltration system for refined sugar mill brings both economic benefits and environmental benefits.