The pressure of a reactor vessel can be adjusted by changing either the inlet or outlet gaseous flow rate. The outlet flow is kept fixed as long as the tank pressure remains between 100 and 120 psi, and pressure changes are treated by manipulating the inlet how control valve. However, if the pressure goes higher than these limits, the exit gas flow is then changed. Finally, if the pressure exceeds 20G psi, a vent valve on the vessel is opened and transfers the gas to a storage vessel, Design a control scheme that meets the performance objectives. Draw a process instrumentation diagram for the resulting control system.