Productivity, Conversion, and Economics Profit

The productivity, rj, of a process is generally defined as the mass of the product, j, produced per unit time and per unit volume it has the dimensions [kg-m h ]. To clarify this concept, the curve (Fig. 2.11) demonstrates for the example of the discontinuous process whose course was diagrammed in Fig. 2.4. With discontinuous processes, a certain lag time is also necessary between production cycles due to harvesting, emptying, cleaning, and refilling operations. This lag time, tg, is shown on the negative time axis in Fig. 2.11. 

Drawing a tangent from this point to the concentration/time curve, one obtains at point 2 the value of the product concentration that can be reached in the whole production time = Iq + t ). The maximum productivity attainable with a discontinuous process can be calculated from 

Point 1 in Fig. 2.11 gives, for comparison, the maximum productivity of an equivalent continuous process. Since a continuous process has no dead time, the slope of the tangent and therefore rj is greater than in a discontinuous process (see also Sect. 6.1). 

The yield, l j, can be determined by Equ. 2.46 (K = constant) it compares the total amount of a product j yielded from an amount of material i consumed 

The output of a reactor, with the dimensions [tons/day], can be calculated from the relation 

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