M. D. Gordon, G. J. OBrien, C. J. Hensler, and K. Marcali [Plant/Oper. Prog., 1, 27 (1982)] utilized a mathematical model to assess the thermal hazard (explosion potential) associated with the amination of ortho-nitrochlorobenzene (ONCB) with aqueous ammonia:

where E = 94.2 kJmol, T is expressed in K, concentrations in mol/L, and the rate in mol/(Lmin). Amination is assumed to occur in the aqueous phase in which the solubility of [ONCB] may be limited, depending on the temperature and ammonia concentration. Although the organic product of this reaction is itself susceptible to explosive decomposition, we wish to consider only the aforementioned reaction as a basis for a preliminary determination of reactor productivity subject to the requirement that the temperature of the reactor effluent not exceed 240C.

(a) If the autoclave is modeled as a single CSTR with a volume of 400 L, and if no solubility limits are incurred, determine the rate at which thermal energy must be added (or removed) if the autoclave is to operate at 220C when the total volumetric feed rate is 16 L/min. The feed stream enters the reactor at 210C. The feed stream is 0.635 M in ONCB and 4.2 M in ammonia. The heat capacity of the process fluid is 3.97 kJ(L C). Sufficient pressure is maintained in the autoclave to ensure that the process fluid remains liquid. The standard enthalpy change for the reaction may be taken as 126 kJ/mol within the temperature range from 150 to 300C. What conversion will be achieved under these conditions? Do not make any more assumptions than are absolutely necessary to solve this problem. In particular, you should not assume that the reaction obeys pseudo first-order kinetics.

(b) To approximate the maximum temperature rise that will occur if the flow of coolant is lost, analyze the autoclave as if it were operating adiabatically. The flow rate and composition of the feed stream are the same as in part (a). Determine the effluent temperature and the fraction of the ONCB that is converted to the product amine. Note that a trial-and-error approach or use of an equation solver will be required. As a first guess, consider an effluent conversion of 60% and refine this value in subsequent iterations to obtain an answer containing three significant figures.