A catalyst tower 40 ft high and 18 ft in diameter is packed with 1-in.-diameter spheres. Gas enters the top of the bed at a temperature of 450°F and leaves at the same temperature. The pressure at the bottom of the catalyst bed is 30 lb_ƒ/in.² abs. The bed porosity is 0.40. If the gas has average properties similar to propane and the time of contact (based on flow in the void space) between the gas and the catalyst is 8 s, what is the inlet pressure?