Which of the following is not fixed by the process requirements, in the design of absorbers ?

ANS:D - None of these.

The aspect not fixed by the process requirements in the design of absorbers is the Flow rate of the entering gas. In the design of absorbers, various parameters are determined based on process requirements. These parameters include the composition of the entering liquid, terminal concentrations of the gas stream, and other operational conditions. These are typically dictated by the specific requirements of the separation process and the desired performance of the absorber. However, the flow rate of the entering gas may not always be fixed by the process requirements. It could be subject to variations depending on factors such as feedstock availability, process conditions, or production demands. Therefore, the flow rate of the entering gas is the parameter that is not necessarily fixed by the process requirements in the design of absorbers.