Metyl ethyl ketone is manufactured by the dehydration of 2-butanol. a simplified description of the process listing the various units used is as follows.
1. a reactor in which the butanol is dehydrated to produce methyl ethyl ketone and hydrogen.
a conversion of alcohol is 88 percent and the selectivity to methyl ethyl ketone can be taken as 100 percent.
2. a cooler condenser in which the reactor off gases are cooled and most of methyl ethyl ketone and unreacted alcohol are condensed. two exchangers are used but they can be modelled as one unit. of the M.E.K entering the unit , 84 percent is condensed, together with 92 percent of alcohol. the hydrogen is non-condensable. the condensate is fed forward to the final purification column.
3. an absorption column in which the uncondensate M.E.K and alcohol are absorbed in water. around 98 percent of M.E.K and alcohol is considered to be absorbed in this unit, giving a 10wt percent solution of M.E.K . the water fed to the absorber is recycled from the next unit, the extractor . the vent sream from absorber, containing mainly hydrogen, is sent tona flare stack.
4. an extraction column in which the M.E.K and alcohol in the solution from the absorber are etracted into trichloroethylene. the raffinate, water containing around 0.5 wt percent M.E.K, is recycled to the absorption column. the extract, which contains around 20 wt percent M.E.K and a small amount of butanol and water, is fed to the distillation column.
5. a distillatio column, which separates M.E.K and alcohol from the solvent trichloroethylene . the recovery is 99.99 percent. the solvent containing a trace of M.E.K and water is recycled to the extraction column.
6. a second distillation column which produces a 99.9 percent pure M.E.K product from the crude product from the first column. the residue from this column which contains the bulk of the unreacted 2-butanol, is recycled to the reactor
For a production rate of 1250kg/h M.E.K
a. draw a flowsheet for the process.
b. estimate the sream flow rate and compositions.
c. estimate the reboiler and the condenser duties of the two distillation colums.
d. estimate the number of theoretical trays required in each column.