Study On The Experiments Of Pretreatment Technology Of Carbon Fiber Production Wastewater

Carbon fiber, known as an important new composite materials, has been applied widely into many fields. With the rapid development of economics and industrialization in China, the needs of carbon fiber is highly increased. However, the standards of water-saving emissions is the nodus of restricting the production of carbon fiber currently. Because there are a lot of processes in producing carbon fiber, various kinds of wastewater will be emerged, which are characterized with large-quantity, complicated-quality, serious-pollution and difficult-dealing. Therefore, dealing with carbon fiber wastewater economically and efficiently is one of the hottest topics in the techonology of wastewater-dealing.These studies attempts to deal with two types of wastewater in the process of producing carbon fiber of Blue-star company by calculating and analyzing various wastewater, on the foundation of data procvided by Blue-star company. The first one, called the mixed wastewater(3m3/h), mainly contains acrylonitrile whose content is up to 3500mg/L and a small amount of alcohols, fiber and other substances. The other is the spinning wastewater (28m3/h), mainly containing formic acid whose content is up to 7000mg/L and a few fiber. Among them, the high concentrations of acrylonitrile wastewater is especially the most difficult to deal with, for it has the characteristics of bad biochemical. Therefore, through comparing different pretreatment methods of deaing with wastewater, this experiment aims to find the best pretreatment technology, which can improve the biochemical properties of wastewater to provide some appropriate conditions to the following biological treatment.Through the systematic studies between the kinds of wastewater treatment, this experimet adopts to the following methods of dealment, that are ferric-carbon micro-electrolysis for dealing with acrylonitrile wastewater, electrolytic technology for dealing with acrylonitrile wastewater, and ferric-carbon micro-electrolysis for dealing with formic acid wastewater. After a series of experiment, the best technological conditions have beem fixed to deal with these two kinds of wastewater. (1)The best technological conditions to ferric-carbon micro-electrolysis for dealing with acrylonitrile wastewater:the pH adjustment is 3.5, reaction time 105min, coagulation precipitate 15min add alkali used when the way interval, aeration time for 90min, precipitation time for 60min, when Fe/C volume ratio is 1:1.5 in the wastewater; (2)The best technological conditions to electrolysis for dealing with acrylonitrile wastewater:electrode for Ti/SnO2 by anodic electrode, the cathode for graphite electrode, voltage of 30V, electrolysis time for 5h, sodium chloride dosing quantity for 0.2g/L, plate spacing 6cm; (3)The best technological conditions to ferric-carbon micro-electrolysis for dealing with formic acid wastewater:Fe/C volume ratio is 1:1, the pH adjustment is 3.0, reaction time 30min, coagulation precipitate 15min add alkali used when the way interval, aeration time for 150min, precipitation time for 90min.Through the comprehensive comparison and analysis of treatment efforts and economic performance of the two kinds of waste water, the author of this thesis deems that the best technological method is ferric-carbon micro-electrolysis. With the best condition, the results to the acrylonitrile wastewater treatment show that the removal rate of acrylonitrile can amount to 91.2%, the removal rate of CODCr can be up to 43.4%, and the fee is 0.92 yuan(RMB) for the treatment of every ton of wastewater. The results to formic acid wastewater treatment show that formic acid have been removed, the removal rate of CODCr can reach 43.78%, and the fee is 1.15 yuan(RMB) for the treatment of every ton of wastewater. The research shows that this technological method has high feasibility in economic and technology, good-effort in pretreatment, and the treatment wastewater meets the requirements of follow-up biological treatment. All in all, this experiment provides the referent vouchers for the engineering.