EXECUTIVE SUMMARY
This work presents the design of a plant that will produce 250000kg/yr of lindane from benzene, chlorine and water at high temperature and pressure using direct chlorination method. The feeds are sent into a chlorinator, the crude product from the chlorinator is continuously decanted into a decanter and the bottom product HCl is further concentrated. Chlorine is seen as the limiting reactant and the unreacted benzene and chlorine are vented. The concentrated fraction of HCl is sent into a stripping column where about 20% of HCl is recovered at the top and the bottom product is recycled. The top product from the decanter is neutralized by 1% NaOH solution, the overhead product being benzene and monochlorobenzene are separated by fractional distillation column where part of the benzene are recycled and the lindane is sent into a crystallizer. The design was based on the principle of material, energy balance, equipment selection, specification and operational cost. The reactor was design and gave a reactor volume of 2.85m3, diameter of 0.646m, height of 9.69m. The lindane reactor has a conversion of 99.5% with a residence time of 11.23s. During the costing analysis, it was shown that the total investment of the project is N4,906,272,200 and with a payback time of 1.22 years and rate return of 81.82% .The final product stream was found to contain 99%γ HCH, 0.22%β HCH, 0.46% α HCH and 0.37% delta and cogeners which meets the specification as described in the statement of the problem.
