CATHODIC PROTECTION DWGB CURRENT RATING 2

[Alaa1992]

HI ALL

IF I CHOOSE A 7 AMPS (19mm*1220mm) MMO ANODE with 7 amps current rating WITH 20 YEARS LIFE PERIOD. HOW IT WOULD BE THE PRODUCTION IN CURRENT OF A GROUND BED STRING COMPOSED BY 15 ANODES OF THIS TYPE? IS IT 7*15=105 AMPS or 7 Amps ??

Alaaedine29




Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer

 

[Kiribanda]

I donot think your approach is correct. I believe that this MMO anodes are for an impressed current CP system.
That means knowing the protected line length or the tank bottom area, soil resistivity etc etc. you must calculate how many anodes you need
to keep the safe potential at 0.85V with respect to a copper cell.

 

[Alaa1992]

@Kiribanda

I read many research absracts to approximate the number of anode on each CP station bed along a 273 Km 36'' Gas pipeline.
I'm preparing a budgetary cost estimation to determine the Number of anode approximately needed in average on each CP station (The client mentionned that the CP station number is about 10)
I'm trying to start from the data which i have: such as environnement conditions, soil nature, pipe coating state (resistance) to determine current needed to protect pipes portions between CP stations.

I ended up with a fact that to protect each section along such 273 KM pipeline conditions, I need to provide 7-10 Amps on each station (distance between stations is between 30 Km & 50 Km depending on soil nature and other conditions).
Firstly, does this pipe current need seamed logic? Secondly, what this could indicate to me on the anode Numbers and their needed current rating ?

I'm thinking to base my cost estimations on max 10 anodes producing between 2A-7A in each CP startion DWGB with depth considerations up to 130m. Does that make a sens base on your experience?
Could that be effective to ensure a good estimation before aceeding to the detailed engineering later , once i get the project?

PS: I'm trying to apply a fast estimation technique starting from similar/analogous expriences because there are no much input data available to me. to ensure that, I'm trying to ask many experienced people and make their opinion aligned with what i have outlined from internet.

Alaa Edine SMAALI
Energy (Oil&Gas) Project Engineer