Recycle-to-Purge Ratio

What is this formula?

The recycle-to-purge ratio compares the amount of material returned to the process with the amount removed through the purge stream. It is an important indicator of how aggressively impurities and inert compounds are being controlled in recycle systems.

When to use it

Use this formula when evaluating recycle loops that include a purge stream. It is particularly useful in reactor systems where inert gases, contaminants, or by-products can accumulate over time.

Example

A process recycles 900 kg/h of material and removes 30 kg/h through a purge stream.

Formula:

RPR = R / P

Substitution:

RPR = 900 / 30

Result:

RPR = 30

The recycle flow is 30 times larger than the purge flow.

Applications

- Chemical reactor recycle systems

- Ammonia synthesis loops

- Hydrogen production plants

- Gas processing facilities

- Process optimization and impurity control