PROPYLENE OXIDE SYNTHESIS

Draw a process flowsheet for the manufacture of propylene oxide according to the following description.

Propylene oxide in the amount of $5000$ tons$/$yr will be made by the chlorohydrin process. The basic feed material is a hydrocarbon mixture containing $90\%$ propylene and the balance propane which does not react. This material is diluted with spent gas from the process to provide a net feed to chlorination which contains $40$mol$\%$ propylene. Chlorine gas contains $3\%$ each of air and carbon dioxide as contaminants.

Chlorination is accomplished in a packed tower in which the hydrocarbon steam is contacted with a saturated aqueous solution of chlorine. The chlorine solution is made in another packed tower. Because of the limited solubility of chlorine, chlorohydrin solution from the chlorinator is recirculated through the solution tower at a rate high enough to supplement the fresh water needed for the process. Solubility of chlorine in the chlorohydrin solution is approximately the same as in fresh water.

Concentration of the effluent from the chlorinator is $8lb$ organics $\frac{?}{100lb}$ of water. The organics have the composition

$\backslash$table$[[$Propylene chlorohydrin,$75$mol$\%$