Key Technology Research Of Dissolved Air Floatation Water Treatment In The Circulating Water System Of Spunlaced Nonwovens

The treatment of circulating water in spunlaced nonwovens process directly affect the production quality, and the dissolved air flotation water treatment system, which is the key cell of water treatment system, directly affect the circulating water quality.In pressurized dissolved air flotation, the filth which adhered to the micro bubbles in water increase quickly, then the filth is removed by slag discharge device. The part circumfluence dissolved air floatation is utilized at most in the circulating water treatment system of spunlaced nonwovens. The key technology of part circumfluence dissolved air floatation is how to form the pressurized dissolved water and produce the micro bubbles. The key components of part circumfluence dissolved air floatation are the jet and releaser. The air is inhaled by the special throat in jet, and the air and water are mixed to form the pressurized dissolved water. The releaser can depressurize the dissolved water, and produce the micro bubbles. In order to improve the water treatment efficiency of dissolved air flotation, the structural performance of jet and releaser need to study. The contents of this thesis include the aspects as follows:1. The basic principle of dissolved air floatation was described. The mechanism of dissolved air, the formation and feature of bubble, the attachment mechanism between bubble and floe and the feature of with gas were analyzed.2. The new type jet with short throat was presented by research the mechanism of dissolved water. Utilizing the software FLUENT to simulate the new jet with the gas-liquid two phase flow model, the influences of the main structural parameters on the vacuum in the internal suction volume were analyzed, and structure was optimal designed. The suction performance of new jet was better than the traditional jet by compared the new jet with the traditional jet.3. The new type releaser with automatic compensation clearance was presented by research the feature of gas in the pressurized dissolved water. Utilizing the software FLUENT to simulate the internal flow field of the new releaser, the results showed that the effect of new relesser was better. The performance of the new releaser was better than the traditional releaser by compared the new releaser with the traditional releaser.4. Combined with the requirements of the water quality of spunlaced nonwovens process, the circulating water treatment system of spunlaced nonwovens process was introduced, and dissolved air flotation was in a key position in the spunlaced nonwovens process.The key cells were optimized designed by the research of the dissolved air flotation, which can improve the circulating water quality. The research has engineering significance of dissolved air flotation water treatment system.