Which is NOT a purpose of chemically cleaning a vessel?

Chemically cleaning a vessel serves multiple essential purposes, particularly in terms of ensuring safety and functionality. The correct choice is that making welds look better is not a primary purpose of chemically cleaning a vessel.

Chemically cleaning a vessel is crucial for preparing it for entry, ensuring that surfaces are free of hazardous materials and contaminants that could pose a risk to workers. Additionally, it is vital for unplugging nozzles, allowing for proper fluid flow and functioning of the system. Removing contaminants is also a significant purpose, as buildup or residue can lead to corrosion, equipment failure, or ineffective operation.

While aesthetically pleasing welds are important in some contexts, they do not constitute a primary objective of the chemical cleaning process. The focus of chemical cleaning lies in safety, function, and maintenance, rather than cosmetic enhancements. Thus, enhancing the appearance of welds is not considered a legitimate purpose for chemically cleaning a vessel.