Minimum hydrogen cyanide production is favored by low residence time, low temperature, and no backmixing. Minimum acetonitrile production is favored by low residence time, high to moderate temperature, and no backmixing. Extensive reactor backmixing reduces propylene conversion, especially at high temperature and residence time. The two main by-products in the acrylonitrile process are acetonitrile and hydrogen cyanide, which are both highly toxic waste. The tanks-in-series model and the axial dispersion model were used to account for the degree of backmixing. The effect of residence time, temperature, degree of backmixing on the steady-state propylene conversion, and production of waste were determined. For the purpose of waste minimization, two modeling methods were used for simulating the performance of the acrylonitrile production reactor, based on the ammoxidation of propylene. Reactor degree of backmixing and operating conditions are important factors that determine the performance of chemical process, including environmental impact. Waste minimization in reactor design is an effective approach for pollution control, when compared to the traditional practice of the end-of-pipe treatment. Finally, a Fourier analysis of the n-CSTR was performed to predict the ability of a unit operation to filter out upstream fluctuations and to model the response to upstream set point changes. The bypassing material fraction for the regime n < 1 was analysed. The n-CSTR model can be used as a stand-alone model or as part of a reactor network. The n-CSTR model is the only model that connects the three fundamental RTDs occurring in reactor modelling by variation of a single shape parameter n: The unit impulse at nā0, the exponential RTD of an ideal CSTR at n = 1, and the delayed impulse of an ideal plug flow reactor at nāā. However, the most interesting feature of the n-CSTR model is the ability to describe short recirculation times (bypassing) with n < 1 without the need of complex reactor networks. The resulting model describes non-ideal back-mixing with n > 1. In this work, the TIS model was generalised to a cascade of n CSTRs with non-integer non-negative n. The tanks-in-series model (TIS) is a popular model to describe the residence time distribution (RTD) of non-ideal continuously stirred tank reactors (CSTRs) with limited back-mixing.
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