Preparation And Production Research Of Viscose-based Activated Carbon Fibers

Activated Carbon Fibers (ACFs) is a kind of carbonaceous adsorption materials with high adsorption performance. Because of the developed pore structure, above50percent of carbon atoms distributes are on both its internal and external surface. Comparing with the traditional granular activated carbon, ACFs have such advantages as narrow pore size distribution, high adsorption capacity and fast adsorption rate that it has been widely used in air purification, water purification, solvent recovery, medicine and health and electronic industries. The main products of ACFs conclude viscose based, polyacrylonitrile (PAN) based, phenolic based and asphalt based ACFs. It is mainly focusd on the production of viscose based ACFs in domestic. Unfortunately, there are some problems existed in the domestic production of viscose based ACFs, such as low yield, adsorption performance and immature process.In view of the problems in the production of viscose based ACFs discussed above, in this paper, we focus on the process of pretreatment, carbonization and activation in the preparation of viscose based ACFs, we also exploits compound impregnant formula with high yield and adsorption performance. Besides, the effects of impregnant concentration, activation conditions on the yield and adsorption performance of ACFs are discussed. Based on the studies in laboratory, ard the problems existed in ACFs’industrial production have been solved, the production process in workshop is improved. The results of this study indicate that:(1) The production cost of ACFs is decreased effectively by using compound impregnant formula I and formula II. The yield and adsorption performance of viscose based ACFs is improved at the same time. In a certain range, the adsorption property is improved with the increasing of impregnant concentration as well as the activated time and temperature. In considering to the practical production needs, when using the impregnant formula I and formula II as impregnant, the load rate should be20%, the activated time and temperature are30min and880°C respectively, water/carbon ratio is5. The ACFs obtained from this preparation conditions have developed pore structure and good adsorption performance. Iodine value, benzene value and methylene blue value reaches to1481mg/g,558mg/g and473mg/g respectively..(2) The research results in laboratory have been applied to the production of ACFs. Since we improved the technique to produce ACFs, the quality of them had been more stable. Enough impregnation time should be guaranteed for the production of viscose based fibers; the speed of the fiber felts should be slowed down properly to ensure the fiber felts stay long enough in carbonized furnace; the amount of water vapor in activated furnace should be increased. The temperature distribution and the air displacement in the carbonization furnace and activation furnace should also be adjusted rationally:the air displacement should be increased in carbonization stage in order to decrease the effect of tar on the ACFs; the activation temperature should be increased properly and the location of air draft should be strictly controlled in activation stage.