Design a reactor system for the production of sulfuric acid (H2SO4) through the reaction between sulfur dioxide (SO2) and oxygen (O2). The reaction rate is given by the equation: r = kC_SO2C_O2 where k is the rate constant and C_SO2 and C_O2 are the concentrations of SO2 and O2, respectively. The following conditions must be met:

1. The production rate of H2SO4 must be 100 kmol/hr.
2. The conversion of SO2 must be 70%
3. The molar ratio of SO2 to O2 must be 2:1.