INVESTIGATION OF APPLICATION OF EXTRACTIVE DISTILLATION METHOD IN CHLOROFORM MANUFACTURE
Advancing the chemical engineering fundamentals
Distillation, Absorption & Extraction - III (T2-10c)
Keywords: Extractive distillation, chloroform, mathematical model
Chloroform finds wide application in a number of industries: in manufacture of chladones, pesticides, in a medical industry, agriculture etc. The available data on consumption of chloroform for last years in Russia show about growing demand for it. Chloroform, manufactured on a basis of methane chloration, contains impurities of ethane – ethylene type and requires a special purification stage. The basic difficulty of separation of closely boiling cis-dichloroethylene - chloroform mixture and azeotrop chloroform - 1,1–dichloroethane is represented.
In research an extractive distillation method for the decision of the specified task of chloroform purification is offered. For this purpose the selection of the separating agent by authors have been carried out and for the chosen separating agents on the basis of the carried out experimental researches the thermodynamic model of vapour – liquid equilibrium in multicomponent system 1,1 - dichloroethane - cis-dichloroethylene - chloroform - carbon tetrachloride - separating agent have been constructed. With use of the basic equation of extractive distillation the efficiency of application of chosen separating agents have been proved. The best separating agents have appeared the substances of a glycol class. On laboratory experimental installation of extractive distillation the research of separation of 1,1- dichloroethane and cis-dichloroethylene from chloroform have been executed. With use of obtained experimental data the adequacy to mathematical model of extractive distillation in the plate column have been established. The mathematical model was based on the equilibrium approach to the description of process taking into account the efficiency of a plate. The carried out numerical experiment the basic regime and constructive data of extractive distillation process, including distribution of the extractive agent on height of a column has allowed to determine. It have been obtained, that for achievement of the required total contents of 1,1- dichloroethane and cis-dichloroethylene in bottom product of extractive distillation column (less than 0,02 % of weights) it is required to support the concentration of the separating agent in a column from 70 up to 85 % mol. The research polystationarity of extractive distillation process have been carried out.
Modeling of stationary modes of operations of the flow chart of chloroform purification from impurities including a column of methylene chloride separation, column of carbon tetrachloride separation, extractive distillation column of 1,1- dichloroethane and cis-dichloroethylene separation, evaporator for separating agent separation and column for manufacturing of grocery chloroform have been executed. By results of modeling the conclusion about expediency of industrial realization of the offered flow chart of chloroform purification by extractive distillation, have been made.
This work was supported by the grant “ BP Corporation Limited ”
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Presented Tuesday 18, 09:25 to 09:45, in session Distillation, Absorption & Extraction - III (T2-10c).
