Purifying Of PNCB And MNCB By Melt Crystallization | | Posted on:2006-05-14 | Degree:Master | Type:Thesis | | Country:China | Candidate:G H Fu | Full Text:PDF | | GTID:2121360182475705 | Subject:Chemical Engineering | | Abstract/Summary: |  PDF Full Text Request | | Nitrochlorobenzene is an important material for organic chemical industry. The mixture of NCB includes three kinds of isomeric compounds ,which differ small in boiling point and great in melting point. Distillation and crystallization are mostly applied to separate the mixture of NCB in industry. The process has more superiority and economic feasibility in coupling distillation and crystallization than using only one of them. Crystallization of PNCB and MNCB were studied in different concentration. The effects of some operating parameters such as cooling rate, final temperature ,crystallization time ,sweating temperature were investigated on crystallization and was analyzed theoretically .The experiment result indicated that there is best cooling rate to get the highest single separable ablility; the rate of crysatllization will decrease and the ratio of mother liquid will increase ,with the improvement of final temperature ; crystallization freezing ratio will increase and concentration of mother liquid will decrease when crystallization time prolong ,but too long crystallization time will drop the total production of machine; final sweating temperature has decisive effect on the purity of products. The optimum operating conditions for two kinds of typical material composition were found out by synthesizing all operation conditions .It was also found that the process of PNCB crystallization will get high purified product ( more than 99 percent) from low concentration ( from 60 percent to 68 percent ) by two-stage crystallization operations; the process of MNCB crystallization will be on condition that crystal particulate is added on right temperature ,and pure product will be obtained by two-stage crystallization when the concentration of MNCB is higher than 90 percent. Finally mathematical equations were gained which fit well the experiment result and good operation parameters were obtained. Furthermore industrial designs which is useful to factory production were finished for two different kinds of crystallization process, laying foundation for large-scale production on PNCB and MNCB of higher purity. | | Keywords/Search Tags: | PNCB, MNCB, melt crystallization, simulate, design | | PDF Full Text Request | Related items |
| |
|
