SIMULATION AND EXPERIMENTAL INVESTIGATION TO PRODUCE ETHYL TERT-BUTYL ETHER USING REACTIVE DISTILLATION

إنجليزية
number: 
2448
Degree: 
Author: 
NADEEN KHALID M. AL-JANABI
Supervisor: 
Prof Dr.Nada B. Nakkash
year: 
2010

     Ethyl tert-butyl ether (ETBE) is primarily used for the production of high octane number gasoline. It is produced by reaction of ethanol (ETOH) and tert-butanol (TBA)over an acidic catalyst where water is also produced as a by-product, using reactive distillation unit which can be considered as reaction and distillation combined into one unit operation.The present work concerned with studying the behavior of batch reactive packed distillation column to produce ETBE experimentally and theoretically. The main objectives of the experimental work is the design and construct a batch packed reactive distillation unit with a heat resistance glass distillation column of 70 cm total height and 3.5 cm inside diameter packed with glass rasching ring of 10 mm length, 6 mm outside diameter, and 3 mm inside diameter. The designed distillation unit has been used for producing ethyl tert-butyl ether by the reaction of ethanol (ETOH) and tertbutanol (TBA) over three types of catalysts Zeolite (13X), H2SO4, and KHSO . The reaction was carried out first using bench experiment to check the performance of catalysts used and their ability to produce ETBE. Zeolite (13X) failed to produce ETBE, while, H2SO4 and KHSO4 catalysts produced ETBE in different purities. Then the reaction is carried out in the batch reactive distillation unit and the effect of many operating conditions on ETBE purity such as feed molar ratio of ethanol to tert-butanol (1:1, 2:1, 4:1), reflux ratios (3, 4, and 5), boiler heat duties of (65, 90, and 146 W), type of catalyst (H2SO4 and KHSO4), and the amount of catalyst have been studied, when the catalyst and the reactants are mixed in the still.The best operating conditions when the reaction takes place in the still are feed molar ratio (FMR) 1:1, reflux ratio 5, boiler heat duty 146W, and H2SO4 catalyst shows a higher purity of ETBE 0.61317% and conversion 94.789% than KHSO4 even when three times the amount of KHSO4 has been used. For the above best operating conditions an experiment was carried out using an intermediate reactive section with KHSO4 catalyst placed in pockets of cloth and is supported in the middle section of distillation column. The results give purity of ETBE 0.79407% and 99.465% conversion which are higher than that gained from reactive still but it is also need large amounts of catalyst. All experiments were carried out at atmospheric pressure. In the theoretical part, Equilibrium (EQ) and Rate-Based or Non Equilibrium (NEQ) models were developed using MATLAB (R2009b) to solve MESHR equations,M: Material balance, E: Equilibrium relation, S: Summation equations, H: Heat balance, and R: Reaction equations. First the equilibrium model was developed and the results were compared with the results of an existed program ASPEN PLUS (10.2) for a certain operating conditions, and it shows a good agreement. The equilibrium model does not take into account the influence of heat and mass transfer on the overall process. Therefore, NEQ model was developed taking into account the effect of mass
and heat transfer in material and energy balances. For the operating conditions studied, the results of experimental work compared with the results of the two developed programs of EQ and NEQ models and the deviation shows with about  10% error, this deviation may be due to the little difference in the size and shape of the packings and the manual set of the distillation column. The results of the two models EQ and NEQ were also compared.



 

 

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