Vapor feed to an adiabatic tubular reactor is heated to about 700F in a furnace. The reaction is endothermic. The exit temperature of gas leaving the reactor is to be controlled at 600F. Refer to FIGURE Q7. rIURE QI Draw an instrumentation and control diagram that accomplishes the following objectives: (i) Feed is flow controlled. (ii) Fuel gas is flow controlled and ratioed to feed rate. (iii) The fuel to feed ratio is to be adjusted by a furnace exit temperature controller. (iv) The set point of the furnace exit temperature controller is to be adjusted by a reactor exit temperature controller. (v) Furnace exit temperature is not to exceed 750F. (vi) High furnace stack gas temperature should pinch the fuel gas control valve