Flow-sheet calculations on individual units

Some examples of how design constraints can be used to determine stream flows and compositions are given below. 

The reactor performance may be specified independently of the detailed design of the reactor. The conditions for the optimum, or near optimum, performance may be known from the operation of existing plant or from pilot plant studies. 

For processes that are well established, estimates of the reactor performance can often be obtained from the general and patent literature for example, the production of nitric and sulphuric acids. 

If the yields and conversions are known, the stream flows and compositions can be calculated from a material balance see Example 2.13. 

With fast reactions, the reaction products can often be assumed to have reached equilibrium. The product compositions can then be calculated from the equilibrium data for the reaction, at the chosen reactor temperature and pressure see Example 4.1. 

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