A 27m3 process vessel containing vinyl chloride must be removed from service and prepared for entry by maintenance personnel. This will entail a process with multiple steps. The vinyl chloride will be emptied of liquid, and the vapor (initially at 35 psig) will be vented to a vapor recovery system until the pressure is 5 psig. Next, a series of pressure purges with pure nitrogen will be used to reduce the vinyl chloride concentration until it is below the OSFC. The maximum purge pressure allowed is 75psig, and each purge will return to 5 psig. After danger of a flammable condition is eliminated, the vessel will be vented to 0psig, and pressure purges with air will be used to create a safe environment for entry. The air purges will be between 75 psig and 0 psig. For a minimally safe environment, the oxygen concentration must be at least 19.5%, and the vinyl chloride concentration must be below the TLV-TWA. The temperature on the day of the process is 20C. The following data are available for vinyl chloride. MW: 62.5 LFL: 3.6% UFL: 33.0% TLV-TWA: 1 ppm a) Write the balanced combustion reaction for vinyl chloride. b) Estimate the LOL, UOL, and LOC values. c) Using the information above, construct an approximate flammability diagram for vinyl chloride. Include the stoichiometric line and air line. Clearly label the points used to construct the diagram. d) Estimate the OSFC. e) Determine the minimum number of nitrogen purge cycles required. f) Find the purge pressure that will minimize the amount of nitrogen for the required number of purges and determine the resulting mass of nitrogen required (in kg ). g) Starting from the OSFC, determine the number of air purges required. h) Determine the composition in the vessel at the end of the process to confirm a safe environment