Evaluation of recommended process conditions: It should be checked whether the process conditions required in the main plant can be achieved in the laboratory scale set-up. These are temperature, pressure, pH, rates of heat and mass transfer etc.
Evaluation from scale up factor: The scale up factor should not be very high. If it is very high a bigger size bench scale plant should be set-up. The ratio should be in the range of 1,000. (If pilot plant is for 1 tons/day, bench scale should be 1 kg/day).
Evaluation from design point of view: Availability of equipment with similar size and proper material of construction, is important as the bench scale is replica of the main plant. The internals of the main plant and bench scale plant should be similar.
Analytical method evaluation: The methods used for testing the products of large plant should be available for testing products of bench-scale plant. These may be available but some new equipment need to be bought.
Evaluation from Safety point of view: Safety aspects such as fire, sudden rise in temperature and pressure, should be considered before starting bench-scale trials. If it is risky, glass equipment should not be used.
Evaluation from operations point of view: Most of the processes involve a number of unit operations. It should be checked whether these are possible on laboratory scale. Filtration, distillation may be possible in laboratory experiment, but catalytic cracking may not be possible, unless proper equipment is set up for that.
Evaluation from effluent generation point of view: The effluent generated in the bench scale plant needs to be treated. However, it will be quite small and the extra load of bench-scale plant will be easily absorbed by the main plant. If the new process creates toxic or difficult to treat effluent, the treatment of this should be taken into consideration.
Market and economic evaluation: This market evaluation need not be done for bench scale plant. However, economic evaluation should be done.
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