Problem 4**. Unsteady State CSTRs Start Up. Consider the following reactor network scheme, A liquid reactant stream passes through two CSTR units in series with volumes V, and V2, repectively. If the reaction is First Order with respect to A (same kinetics in both reactors) or ra = -KCA Cai= a, where a is constant Q = constant 1 Vi 406 CAI(t) V2 = 2 V CAO = 0 Caz(t) where Q is the inlet flow rate, k is the reaction rate constant, Cai(t) is the inlet concentration, Cao is the initial reactor concentration inside both reactors, Cai(t), is the concentration of reactant in the first reactor and , CA2(t), is the concentration of reactant in the second reactor and Vi is the reactor volume for the first reactor and V2 is the reactor volume for the second reactor(V2 = 2 V), thus the mean residence time T2 is twice ti. (Remember, residence time t=V/Q) QUESTIONS (a) Perform a material balance on each reactor and find the governing equations that describe their behavior. (b) Solve the 2 resulting differential concentration equations for Ca(t) and Caz(t) as a function of time with the initial conditions at time = 0, CAI = CA2 = CAO = 0