A chemical industry will start the operation of a heterogeneous catalytic process of a highly exothermic reaction, operating with gaseous reactants and solid catalyst. Your boss needs to define which reactor he will use in this process. Based on this information and your knowledge of chemical reaction engineering, answer:

$($a$)$ stipulate the bases and fundamentals associated with the use of two distinct heterogeneous catalytic reactors applicable to this reaction, discussing advantages and disadvantages associated with the use of each of them $($make a schematic drawing of the equipment$),$ determine which of the two you would recommend and why you chose it$.$

$($b$)$ Name and explain the physical and chemical processes involved in the heterogeneous catalysis process, make a schematic drawing of the steps involved, describing them and present the relevance of mass transfer to this process.