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At the moment I am in the commissioning team of a Hydro cracking construction. We are still in the engineering phase of the project but soon we will start with on site field erection. As I am not familiar with Hydro crackers what is forum advice on inspection matters of this kind of units? What we should look closer in the disciplines of rotating, static and piping equipment. I know the main corrosion mechanisms in hydro crackers is ABS (ammonium bisulphide corrosion) and high temperature corrosion related with hydrogen but I would like to know from forum experience inspection point of view at what matters the commissioning inspectors must take more attention.
 
Answers
11/09/2009 A: Lindsay McRae, Pall Corporation, Lindsay_McRae@pall.com
During commissioning it is critical to pay attention to recycle gas compressor lube system. This is not always done well and can lead to compressor reliability problems that effect HCU availability. This HCU recycle gas compressor is critical, and becuase of the high cost of this compressor it is not usually duplexed so there is often no spare compressor. So its reliability is very important indeed. Typically the lube system should be flushed with a flushing rig to achieve a suitable reynolds number (to create turbulent flow) to flush out contaminants in the piping that enters during manufacture, shipping and during installation. Also the lube oil should be filtered with a suitable filter trolley as well during transfer of lube oil into the system Once suitable cleanliness level is achieved by flushing, the compressor can be commissioned. This is important to do to minimise wear in the the compressor and extend the life of the bearings. Pall Corporation offers such a commissioning service and also consulting services for commissioning of critical rotating equipment in refineries, power plants, and petrochemical industries.
We also provide filtration and separation equipment such as high efficiency SepraSol Liquid Gas coalescers to prevent damage to compressors caused by liquid and solid contaminants (like ammonium disulphide, Iron sulphides, ammonium chloride and hydrocarbon liquids) in the process gas. This may be applied to the recycle H2 gas stream or to the fresh H2 make-up gas stream as well.