Pipeline Availability Calculation. 1

[Julio8287]

Please, if you have some information about availability calculation for Pipeline Gas Transportation or other factors like reability.

Thks in advance.

 

[BigInch]

Availability = Time running / Total time

Reliability of Delivery = Sumation of volume delivered/(Flowrate Capacity * (Time2-Time1))

Typical calculations for flowrate normally use availability figures >= 90% for multiproduct lines, maybe as low as 85% if delivered or shipped to marine terminals and maybe up to 95% for gas pipeline deliveries, all of which are conservative. 99.5% would not be an unusual availability for gas pipelines.

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[BigInch]

I have some more time today.

Multiproduct pipelines often have a reduced availability due to the potential for errors in the more complicated schedules you must make in order to ensure availability of the appropriate product tanks whenever a particular product is scheduled to be delivered. Larger tanks and more of them for each product will help increase the overall availability of the system.

The above numbers assume you have a reasonable number of standby pump and compressor units to keep your delivery flowrates to the high side when such units are down for maintenance, scheduled or unscheduled. For example, if you only have 1 pump that will only be working 50 weeks of the year, but your deliveries are required every week, you would obviously need to increase your flowrate and tank sizes by at least 52/50, or 4%. That can be compounded even more for multiproduct pipelines where you may have sufficient tanks available for one product, but not enough for others. In such circumstances it could cause you to raise your pipeline flowrate just to have enough flexibility to manage the supply of one product alone, or alternatively look for space to build some additional tanks.

Marine terminals are often less available, because of variations in ship arrival times due to weather, harbour traffic delays, etc. and tend to also be less available as shipping distances between sources and destinations increase.

An availability calculation that considers things other than the typical equipment failure and time to fix, or scheduled maintenance issues can be quite complex. A monte carlo simulation considering all these factors is often the only way to do a realistic calculation to prove the availability will be really what you think it should be.

"I am sure it can be done. I've seen it on the internet." BigInch's favorite client.

"Being GREEN isn't easy." Kermit

http://www.youtube.com/watch?v=hpiIWMWWVco

http://virtualpipeline.spaces.live.com

 

[stanier]

Pipeline Risk Management by Mulhbauer will give you a head start.