Which example represents an in-line refrigerant cleaning system for use with a centrifugal compressor containing R123 refrigerant?

The correct choice is the example that identifies a refrigerant recycling process. In-line refrigerant cleaning systems are designed to purify refrigerants, particularly in applications involving centrifugal compressors that utilize specific refrigerants like R123.

Refrigerant recycling involves filtering and cleaning refrigerant that is already in use or recovered from a system, ensuring that it meets necessary purity standards before being reused. This is crucial for maintaining the efficiency and lifespan of the compressor and is especially relevant when dealing with refrigerants, as improper handling can lead to system inefficiencies or failure.

In contrast, refrigerant recovery typically refers to the process of removing refrigerant from a system for the purpose of disposal or storage, but does not necessarily involve cleaning or purification. Refrigerant charging is simply the act of adding refrigerant to a system, and refrigerant expansion refers to the process by which refrigerant undergoes a reduction in pressure as it passes through an expansion valve, which is not related to cleaning or recycling.

This distinction highlights why the recycling process is critical in the context of maintaining high performance and compliance with environmental regulations in refrigeration systems.