Consider the flowsheet for the manufacture of vinyl chloride in Figure 2.6.

(a) If the pyrolysis furnace and distillation towers are operated at low pressure \((1.5 \mathrm{~atm})\), what are the principal disadvantages? What alternative means of separation could be used?

(b) For the process shown, is it possible to use some of the heat of condensation from the \(\mathrm{C}_{2} \mathrm{H}_{4} \mathrm{Cl}_{2}\) to drive the reboiler of the first distillation tower? Explain your response. If not, what process change would make this possible?

(c) Consider the first reaction step to make dichloroethane. Show the distribution of chemicals when ethylene is \(20 \%\) in excess of the stoichiometric amount and the chlorine is entirely converted. Assume that \(100,000 \mathrm{lb} / \mathrm{hr}\) of vinyl chloride are produced.

(d) Consider the first distillation tower. What is the advantage of cooling the feed to its bubble point at \(12 \mathrm{~atm}\) as compared with introducing the feed at its dew point?

(e) Why isn't the feed to the pyrolysis furnace heated with the hot pyrolysis products?

(f) What is the function of the trays in the direct chlorination 3 reactor?

(g) Suggest ways to reduce the need for fuel and hot utilities such as steam.

Figure 2.6:-

Transcribed Image Text:

Vapor at Boiling Point Preheater Vapor at Dew Point Cooling Water Condenser 242C Evaporator Steam 26 atm Liquid CHC 1.5 atm, 26 atm 500C 500C 170C Cooling Water Cooler CHC 158,300 26 atm. Pyrolysis Pump lb/hr Furnace Spray Quench Tank Ch Liquid Liquid at 113,400 lb/hr 90C, 1.5 atm Bubble Point HCI 58,300 lb/hr 33.1C Impurities Condenser CH 44,900 lb/hr Drawn Off 90C -26.2C 12 atm CHCI 100,000 lb/hr 4.8 atm Direct Cooling Chlorination Water Refrigerant Reactor 146.1C Cooler 93C CHCh