Simulation phenol hydrogenation

Figure 5.21 Simulation of one-reactor phenol hydrogenation process.

To date, numerous model compounds simulating the pollutants in common waste streams have been studied under laboratory-scale conditions by many researchers to determine their reactivities and to understand the reaction mechanisms under supercritical water oxidation conditions. Among them, hydrogen, carbon monoxide, methanol, methylene chloride, phenol, and chlorophenol have been extensively studied, including global rate expressions with reaction orders and activation energies [58-70] (SF Rice, personal communication, 1998). 

Two additional simulations are presented in Figures 5.27 and 5.28, where reactor-inlet phenol and reactor-inlet hydrogen are, respectively, varied, while keeping constant the flow rate at the reactor inlet for the other reactant. These alternatives work satisfactory from the control viewpoint but lead to variation in selectivity, which probably is not desired. 

After closing the material and heat balances, we will examine the potential environmental impact (PEI) of the design. The basic information is the stream report. Table 5.16 shows material- and heat-balance data for a fresh feed of 150kmol/h phenol and 350kmol/h hydrogen, in total 14822.5kg/h. The products are cyclohexanone 9618.9 and 5017.9 cyclohexanol in the molar ratio 2 1. After simulation it is found that the amount of waste is 150.6 kg/h lights and 80 kg/h heavies. These data lead to a global yield of raw materials of 98.75%. 

Enol imine-enaminone and phenol—quinone tautomerism in (arylazo) naphthols and in analogous Schiff bases were studied by Fabian et al. [92, 93]. In all these molecules there is a favorable N- -H- -O intramolecular hydrogen bond. Depending on the X-H sigma bond (X = N, O), there are two possible tautomers in solution. The solvent effect was calculated on the equilibrium [92], and a combined effect of the solvent and the benzene substituent was studied in [93]. While the FEP/MC simulations provided consistent organic solvent effects in accord with the experimental results [92], the wide spectrum of the solvent-effect calculation methods could predict rather diverse results for several groups of systems in [93]. 

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