GTL and North Slope Gas

[bonzoboy]

General question. What do you guys think about the idea of using GTL on North Slope (and ANWR) natural gas conversion, and then using the Alaskan pipeline to deliver the GTL liquids? The pipeline (as I understand) is at much lower capacity than in the 1980's. There are 240 tcf of gas on the North Slope, and more showing up.

Anybody think this makes sense? As I understand, GTL products can be delivered at prices of $30/bbl. But that is $30/bbl of high quality product, not $50 of heavy crude.

It must be cheaper than moving natural gas in a $30 billion pipeline across 5,000 miles of arctic wilderness.

Thoughts??????

 

[Mutt]

Used to be a lobby group looking at us that - haven't heard much lately. Most of the big GTL guys made proposals. Biggest concerns probably environmental - e.g. large human impact to support such facilities.

Also out of curiosity (ignorance?) - aren't long distance liquid pipe lines quite diferent in design to gas ones? e.g. Can have some thick pipe wall requirements at low points due to liquid heads.

 

[MortenA]

Are you thinking about liquified gas (cryogenic) or converting the gasses (methane, ethane) to light pretroleum fraction using e.g. Fisher-Trop?

Best regards

Morten

 

[rmw]

The term GTL connotes FT process liquids.

rmw

 

[MortenA]

"connotes"? I am sorry english is not my mother tounge and im afraid i dont know this word (or can recognise it as a spelling error of some other word - something that i usually is very liberal with).

Anyway some people uses GTL about the crogenic process - since the outcome is - ta-dah - a liquid (not commenting on the correctness of this just observing)

Best regards

Morten

 

[rmw]

Connotes refers to the common useage of a word, while the word denotes refers to the dictionary definition of a word.

For example, to a teenage in my past, the word "cool" connoted 'good' or 'OK' or 'groovy' while to me as an engineer, the word cool denotes a reference to a temperature relationship.

GTL generally connotes hydrocarbon liquids made from NG using the FT process, while NG refrigerated to its liquid state is referred to as LNG, and liquids of other constituentes of natural gas in their liquid state are referred to as LPG.

Anyone who is using GTL to refer to the cyrogenic process of liquifying NG is not using the common use of the term GTL. Not that refrigerating NG to its liquid state is not 'gtl'.

If you google GTL you will find most of the information pertains to converting (mostly stranded) NG to light hydrocarbon liquids that can be transported by conventional means (pipelines, boats, barges) to existing markets, transportation fuels, for example.

While I haven't done the google thing in a while, I would be shocked to find references to LNG as GTL. But, I am always willing to learn.

rmw

 

[DrillerNic]

I'd second RMW- GTL is a way of getting strnded gas to market using pipelines tankers or whatever, LNG is a way of transporting gas very long distances to market (and almost by definition, if you've got enough gas for an LNG plant, it isn't stranded gas!). GTL is a possible alternative to LNG though....

As for gas vs oil pipeline engineering, although you may find that a liquid pipeline needs heavier wall thickness at some points due to line packing, in the two ASME pipeline codes the oil pipeline design factor is fixed at 0.72, whereas gas pipeline design factors can be as low as 0.4 depending upon the habitaion around the pipeline, so you often find that the two things may cancel out and the total cost of the pipe is about the same for the same diameter and design pressure. However, a Main Oil Line pump is a lot cheaper than a large multi stage gas export compressor with it's intercoolers etc...

 

[bonzoboy]

My original question was targeted at producing "liquid" hydrocarbons, liquid at ambient conditions, via Fischer-Tropsch. That would eliminate the need for cryogenic shipping out of Valdez, and using a more conventional pipeline approach. Exxon's Oryx plant in Qatar is something like $7 billion investment. So why not do that in Alaska? Economics against it? Environment against it? Is it just easier to do in some third world country?

Bonzoboy

 

[rmw]

I am not going to go root around on the internet to find it again, but I just saw something on the net about a proposed GTL plant for Alaska north slope gas using capacity on the now more lightly loaded Alaska pipeline that had fallen into disfavor for some financial or political reason being promoted or some such thing by the Governor of Alaska within the last 3-5 days.

I thought of this thread when I saw it. If I come back across it, I'll post the link. You might try googling all the pertinent words.

rmw