Catalytic Oxidation Of Benzene Case Study

2. The gas phase catalytic oxidation of benzene reactor model and evaluation of the parametric sensitivity

To illustrate the parametric sensitivity analysis, the case of gaseous phase catalytic oxidation of benzene to maleic anhydride was considered (Lupușor et al., 1981). The multi-tubular reactor (heat exchanger type) with the fixed bed catalyst inside a small diameter tubes (under 3 -4 cm) is continously cooled by molten salt mixture (nitrates and nitrites mixture; Maria , 2007). The raw materials are air (oxygen) and benzene. The compressed and filtered air is heated into a preaheter (using the heat coming from the reactor outlet) is mixd with benzene vapours at a concentration below the lower explosion limit (LEL, 1.5%). The benzene/air …show more content…
1. Chemical reactions involved in the oxidation of benzene (adapted from Lupușor et al., 1981)
In order to achieve such an analysis, a simplified mathematical model of the reactor was used considering a pseudo-homogeneous, one-dimensional, plug-flow reactor. Model equations are presented in the Table 1 in terms of the mass balance of the considered chemical species, heat and moment balance, with the rate constants given in Table 2:

Table 1. The fixed bed multi-tubular reactor model used for benzen oxidation to maleic anhydride
Mass balance differential …show more content…
Momentum balance: - friction coefficient calculated by Ergun and Hicks formula:

- Reynolds number for flow through the catalytic bed. - catalyst particle diameter, m; - gas flow velocity, ; - gas density, ; - gas viscosity, . (Froment and Bischoff , 1990)

The model hypotheses:
Molten salt bath temperature (cooling agent) is considered