Stirred cell reactor selectivity

Negligible and medium interaction regimes. Experiments were carried out with an aqueous 2.0 M DIPA solution at 25 °C in a stirred-cell reactor (see ref. [1]) and a 0.010 m diameter wetted wall column (used only in negligible interaction regime, see ref. [4,5]). Gas and liquid were continuously fed to the reactors mass transfer rates were obtained from gas-phase analyses except for CO2 in the wetted wall column where due to low C02 gas-phase conversion, a liquid-phase analysis had to be used [5]. In the negligible interaction regime some 27 experiments were carried out in both reactors. The selectivity factors were calculated from the measured H2S and CO2 mole fluxes and are plotted versus k... 

Figure 3. Selectivity factor S as a function of kgHts in the negligible interaction regime. Key O, stirred cell reactor +, wetted wall column, cocurrent and X. wetted wall column (countercurrent).

The perfonnances of amine blends to absorb CO2 were evaluated for mixtures of DEA and MDEA using a laboratory stirred cell reactor. The DEA to MDEA ratios were selected so that DEA-CO2 reaction would not dominate the overall reaction rate. It was observed that the addition of small amounts of DEA to MDEA resulted in a significant increase in the CO2 absorption rates as shown in Fig.l which, can be attributed to the higher reactivity of DEA with CO2. 

Selectivity in Stirred Cell Reactor. Observed 1 — ij is always 1. Therefore eqn. (6) is expected to be applicable though its accuracy is probably low due to the discussed interface viscosity increase. From eqn. (6)... 

Aromatic Sulfonation in a Cyclone Reactor, a Stirred Cell, and a Cocurrent Tube Reactor Influence of Mass Transfer on Selectivity... 

For example, different fermentation schemes have been developed for the production of ethanol. Conventional batch, continuous, cell recycle and immobilized cell processes, as well as membrane, extraction and vacuum processes, which selectively remove ethanol from the fermentation medium as it is formed, were compared on identical bases using a consistent model for yeast metabolism (Maiorella et al., 1984). The continuous flow stirred tank reactor (CSTR) with cell recycle, tower and plug flow reactors all showed similar cost savings of about 10% compared to batch fermentation. Cell recycle increases cell density inside the fermentor, which is important in reducing fermentation cost. 

To model a packed bed of wood particles pyrolysis and char conversion schemes can be selected from the database. Homogenous reactions within the void space are modelled by describing each volume cell in the numerical grid of the flow model as a continuous stirred reactor. Due to the lack of reliable kinetic data for the conversion of gaseous species under packed bed conditions, only the conversion of hydrogen and carbon monoxide is currently taken into account. For the combustion of hydrogen an infinite rate is assumed whereas the conversion of carbon monoxide is calculated according to [17]. 

Perhaps the first decision to be made in process development is the difficult decision of whether the enzymes to be used should be used in an integrated format. Such a question does not arise with conventional single biocatalytic steps but is highly important in multienzyme processes. One of the key criteria here is whether the enzymes can be operated together without compromise to any of the individual enzyme s activity or stability. An interaction matrix (see Section 10.6) can be used to assist such decision making. In cases where the cost of one or more of the enzyme(s) is not critical, it will be possible to combine in a one-pot operation. In other cases, where the cost of an individual enzyme becomes critical, then it may be necessary to separate the catalysts, such that each can operate under optimal conditions. Likewise, selection of the biocatalyst format (immobilized enzyme, whole cell, cell-free extract, soluble enzyme, or combinations thereof) in combination with the basic reactor type (packed bed, stirred tank, or combinations thereof) and biocatalyst recovery (mesh, microfiltration, ultrafiltration, or combinations thereof) will determine the structure of the process flowsheet and therefore is an early consideration in the development of any bioprocess. The criterion for selection of the final type of biocatalyst and reactor combination is primarily economic and may best be evaluated by the four metrics in common use to assess the economic feasibility of biocatalytic processes [29] ... 

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