Materials Degradation and Probability of Failure of

Piping in Closed Drain System You have been employed by a service provider company and have been asked to carry out RBI analysis of a portion of an offshore topside facility. Carry out the required analysis in Excel and submit a report to the client.

Background

Water $($containing some oil and gas$)$ is collected from different equipment and

sent to Closed Drain Vessel. In this vessel final separation of the three phases $($gas$,$

oil and water$)$ takes place.

$1.$ Gas separated from liquid is sent to LP Flare Header

$2.$ Oil rich water is recycled to First Stage Separator

$3.$ Water is sent to Hazardous Drain Caisson for safe disposal Year of installation $=2010$

Rate of corrosion for hydrocarbon $($gas or liquid$)$ corrosion of carbon

steel:

Mean rate is $0,25$mm$/$year

Standard deviation is $0,2$

Rate of corrosion for hydrocarbon corrosion of carbon steel after

addition of corrosion inhibitor:

Mean rate is $0,025$mm$/$year

Standard deviation is $0,2$

Operating temperature $=50$oC

Operating pressure $=20$ bar Material data sheet NORSOK L$001$

Product Service Codes $=$ DNV$-$RP$-$G$101$

Insulation:

PP $$ Personal Protection

PFP $$ Passive Fire Protection

No Mention $$ No insulation