The irreversible elementary gas phase reaction 2a --> b + c is currently carried out in a packed bed reactor (pbr) containing 100 kg of catalyst. the entering pressure is 20 atm and the exit pressure is 4 atm. under steady state operating conditions, 50% conversion is achieved. it is proposed to add a cstr with 200 kg of catalyst downstream of the pbr. there is no pressure drop in the cstr. the flow rate and temperature remain unchanged. (a) what would be the overall conversion in such an arrangement? (b) is there a better way to carry out the reaction (i. e., increase conversion), and if so what is it?

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?