Research On The Influence Of Closure Recirculation Of Whitewater In Paper Machine To The Production Of High-strength Corrugating Medium

With the growing pressure of resources environment, in order toreduce the environmental pressure of our papermaking industry, how tomake full use of the present resources, especially the water resources isworth deeply research. From the current existing energy savingmeasures, the influence of papermaking effluent closed recycle is afeasible way. However, based on the consideration of pulping andbleaching, the papermaking processes are special, and at the momentputting a generally paper water closed into practice is more difficult. Amore feasible scheme is implementing whitewater system closed recyclein the paper machine system.In paper making process, the whitewater contains, not only smallfiber, packing, but also additives and water, little real useless waste,most of all can be reclaimed. But as the more recycle times and closedrecycle degree, the more in the constant, and the harmful substances inthe whitewater also built up gradually to a high degree, such asdissolved and colloidal substance(DCS). The accumulation of thepollutants will cause trash, microbial growth, secondary adhesives, theaccumulation of salt and corrosion, they can serious influence on thestability of the paper operating and the product quality, it is needcertain research for water system and solve the whitewater systemclosed recycle.This topic is aimed at the research of a paper mill’s whitewater system closed recycle in Xi’an, and putting forward the methods forsolution. First of all, dealing the off-line whitewater with flocculationand precipitation methods, finding the appropriate treatment conditions;Secondly, analog the production process for whitewater circulationreuse, discussing the influence of the circulation number of whitewateron paper strength, and from the changes of water quality to illustrate,through comparation, making the conclusion of the balance ofdeteriorated water and paper, that means the best recycle times; Finally,with the most suitable water treatment approach to treat water inequilibrium point, with the treated water and then also to whitewaterclosed cycle, observed the influence of paper strength after watertreatment, proposing the feasible water circulation scheme.Experiments were using PAFC with PAM coagulation treatment,PAFC and K2FeO4coagulation treatment, PAFC and modified fly ashcoagulation treatment and joint PAFC and PAM with fly ashcoagulation treatment to deal with the off-line whitewater respectively.Through comprehensive consideration of the treatment effect, operationand cost accounting analysis, finally choosing joint PAFC and PAMwith fly ash coagulation treatment to deal with the off-line whitewaterwas the most suitable for the this enterprise’s whitewater processingmethod. By this method, water pollutants could respectively achieve thebest removal rate: COD60.0%, TS80.4%, DCS83.6%and DS93.9%,reached to the requirements of recycling water in waste paper producthigh-strength corrugating medium.Simulate the production process with whitewater circulationrecycle in lab to make paper. From the experiment obtained that in thepapermaking process, the more kinds of additives, the faster the paperquality problems arrival in the whitewater circulation. In whitewaterrecycle, the balance point were separately reached in no additives40times, adding1%cationic starch35times, adding1%cationic starchadding and0.15%cationic30times.Using the fly ash ambined with PAFC and PAM coagulation totreat the water in a significantly deterioration recycling times, making paper with treatment water in the laboratory to simulate productionprocess water circulation reuse again. From the experiment, the paper’sproperties improved after whitewater treatment processing, still can becirculation many times to have obvious paper nature declinerespectively. With no additives whitewater closed cycle can up to15times, adding1%cationic starch, adding1%cationic starch and0.15%cationic PAM were all10th. And compared with before, at leastincreased a third of reuse time.Finally, combined with the laboratory results and the actual offactory, the appropriate solutions for were: in the original of off-linewhitewater into disc filter, reuse many times to a cycle to carry outflocculation treatment, after flocculation, the water directly into thepaper machine system cycle again, this method has increased thewhitewater reusing time at least a third of reuse time. When comparedwith the coagulant adding, the cost is far less than that of watertreatment in water treatment plants.