LUDE CHEM Factory-The production process of Polyanionic Cellulose (PAC) takes chloroacetic acid and refined cotton as the main raw materials, and goes through the processes of dissolving, alkalizing, washing, rake drying and drying in ethanol medium to obtain the production process of sodium carboxymethyl cellulose.
The production device mainly includes five parts: with acid-alkaliization, washing, rake drying, residual night distillation device.
The technological process is briefly described as follows:
1. With acid-base chemical section
Add 95% alcohol, add solid chloroacetic acid under stirring to form a 57% solution; add the weighed refined cotton and the measured liquid caustic soda into the alkalizer at the same time, and evenly penetrate into the cellulose. , to alkalize
For 60 minutes, the process was over alkaline and the pH was 12. After the alkalization, the measured chloroacetic acid 57% was evenly added to the alkalizer. Alkalization time 60 minutes. Alkalization of cellulose to alkali cellulose:
Cell-(OH)3+xNaOH→Cell-(OH)3-x(O-Na+)x+xH2O
2. Etherification process
The alkalized material is fed into the etherification machine, and the temperature rises in the etherification machine for about 90 minutes.
Cool down to 40-45 degrees, and feed into the washing tank for washing. Alkali cellulose and sodium chloroacetate are converted to:
Cell-(OH)3-x(O-Na+)x+nClCH2COONa→Cell-(OH)3-x (ONa) x-n(OCH2COO-Na+) n + nNaCl
3. The prepared alcohol is poured into the washing tank first, then unloaded from the etherification machine to the washing tank, and the pH value is measured, then add hydrochloric acid to neutralize, pH=7, stir for a certain time (20 minutes), and then pass the screw pump It is pumped into a centrifuge for solid-liquid separation, and the solid cellulose continues to recover alcohol in the next process. The liquid part enters the waste wine tank and is pumped into a distillation tower for alcohol purification. The ethanol-containing waste gas produced by the distillation process, the raffinate after purification is a liquid containing NaCl and a small amount of sodium carboxyethylate, and the NaCl-containing solid is continuously distilled and crystallized; the distilled liquid phase enters a mechanical vapor recompression (MVR) evaporator, containing The NaCl with a small amount of water is centrifuged, and the solid containing NaCl is sold to other manufacturers, and the centrifugal liquid phase re-enters the three-effect evaporation system. Neutralized and washed:
Cell-(OH)3-x (ONa) x-n(OCH2COO-Na+) n+( x-n)CH3COOH→Cell-(OH)3-n(OCH2COO-Na+) n+( x-n)CH3COONa
4. Rake drying section
The cellulose solid material from the centrifuge, with a moisture content of 45%, enters the air lifter through vacuuming, rake drying, and heating to recover the alcohol in it. The rake drying process produces organized exhaust gas containing ethanol; fiber The raw solid material enters the drying and pulverizing process, and finally the product is obtained. The drying process produces waste gas containing ethanol in an organized manner; the waste gas in the pulverization process is collected by the pulse dust collector, and the powder screen filters the product dust and waste gas generated by the pulse dust collector. Exhaust through the exhaust pipe. The dust collector collects the dust and mixes it with the product for sale.
