Kinetic Data

The three types of laboratory and pilot plant data on which reactor designs are based are:

1. Measurements of composition as a function of time in a batch reactor of constant volume at a substantially constant temperature

2. Measurements of composition as a function of feed rate to a flow reactor of constant volume operated at constant pressure and substantially constant temperature

3. Measurements of composition as a function of time in a variable-volume batch reactor operated at constant temperature and substantially constant pressure.

The third type of data is less common than the other two, and the experimental technique is more difficult. A variable-volume reactor generally depends on varying the level of a confining liquid such as molten metal to maintain constant pressure. This method works well where the volume of the reacting system is difficult to calculate such as when a change of phase accompanies the reaction. It has the advantage of yielding positive rate measurements and data on the specific volume of the reacting system at the same time.

Data of the second type are generally the most dependable and simple to obtain. This method is directly applicable to the flow-type reactor. Data of the first type at constant volume are satisfactory except where added moles of gas result from the reaction. In such cases, the varying pressures make the data more difficult to interpret for complex systems (Hougen and Watson 1947).

Levenspiel (1972) provides more information about the methods for analysis of experimental kinetic data of complex reactions.

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