Gas processing inevitably leads to the separation of gas into its constituent components. Water and NGLs (Natural Gas Liquids) are recovered in process plants mainly so that sales gas can meet dew point specifications agreed on with the pipeline company providing transmission to markets.
As discussed, lean gas streams might only produce nuisance amounts of water, to be disposed of at site. However more frequently, as shale gas and condensate production dominate current production, more liquids a.k.a. condensate are recovered at field gas processing facilities especially designed to recover the predominant constituents of the gas streams.
These recovered liquids are typically sent to centralized, larger fractionation plants where components such as ethane, butane, propane and pentanes are removed.
As recovery of smaller liquids quantities may not be economical for producers some NGL’s may be sent down the sales line, provided the product still meets contract dew point specifications. The pipeline owners may put up “straddle plants” to recover accumulated liquids from multiple sales points.
The future of Natural Gas Liquids is positive
As NGL’s are becoming increasingly valuable, more producers can justify the economics of installing deethanizer, debutanizer and depropanizer towers at their refrigeration facilities. The products from these towers needs to be stored in pressurized storage vessels, typically horizontal bullets ranging from 18,000 USWG through to 90,000 USWG, but sometimes even larger.
The predominant sizes moved about in Canada tend to be the 30,000, 60,000 and 90,000 USWG range with the larger ones getting quite heavy and being a greater logistical challenge than the 30,000 USWG sizes do. As a result it’s quite common to see multiple storage bullets at a single plant.
How various gases compare
Ethane is the largest constituent of natural gas streams. Propane’s use in residential, commercial, industrial agricultural and transportation applications, paired with its inherently clean combustion profile make its availability of great economic importance now and in the future.
Butanes are frequently mixed in blends and used as feedstocks for value added products including octane additives for gasoline and methanol as well as its use as diluent to ease bitumen transport.
Pentanes and higher C-content products make up bitumen diluents and have many more applications and are highly valued. Various Industries’ drive towards higher ESG standards are a strong driver behind the demand both for Alberta’s oil and gas but also within the energy industry itself as clean burning gas has a considerably lower environmental impact than many alternatives.
For this reason, demand for pressurized storage of these liquids is up since 2021 in Canada.
Why buy a storage bullet from OilPro?
OilPro spends time to do the up front work of ensuring an NGL bullet meets today’s regulatory requirements, checking boxes in areas such as metallurgy (thus eliminating many older bullets), and increasingly MDMT (Minimum Design Metal Temperature and corrosion allowance.
MDMT is key as many lower grades of carbon steel can lose their ductility at temperatures below -20F. For this reason a producer can choose to either insulate the bullet or to upgrade to a different material with a lower MDMT such as -40 to even -50F in Canada. Pre 1988 ASME code did not require impact testing and as a result some pre 1988 vessels should not be assumed to have good fracture toughness down to -20 F.
OilPro always recommends the application of API RP 579 Fit-For-Service criteria prior to installation
Call OilPro for pressurized storage of propane and butane to meet both emissions and to take advantage of the increased demand for Canada’s NGLs. OilPro’s high standards will ensure you have a vessel with proper Quality Control and transfer paperwork that will last for decades to come.
Interested to learn more?
Call OilPro directly at 403-215-3373 or email us at [email protected].