ONSHORE FACILITIES & REDELIVERY POINTS
On arrival at the terminal the CATS gas is passed through reception facilities and treated to reduce the H2S content to meet the required National Transmission System (NTS) specification, and full Mercury removal using solid bed adsorbent.
After this point the gas is redelivered, in dense phase, via fiscal metering for processing to the CATS gas processing facilities via the Ex1 redelivery point and the Teesside Gas Processing Plant (TGPP) processing facilities via the Ex2 and Ex3 redelivery points.
The CATS processing facilities consist of two trains each of 600 mmscfd capacity. The two trains are essentially identical, with the gas being dried in dehydration towers (TEG cold finger regeneration system), passed through a feed gas heat exchanger and onto either a Turbo-expander (Train 1) or a Joule-Thompson Valve (Train 2) for pressure reduction to NTS levels which causes further cooling. Expanded gas and liquids are passed to the Low Temperature Separator (LTS) where the gas and raw NGLs are separated. This sales gas is heat exchanged with the incoming gas, metered and sent to the NTS.
The liquids from the Low Temperature Separator are fed into a fractionation system consisting of a stabiliser, depropaniser and debutaniser. In the stabiliser column the NGLs, are stripped of methane and ethane. These gases are compressed and injected into the sales gas stream. The stabiliser bottom product is fed to the depropaniser which strips out the propane product. The remaining liquids are sent onto the debutaniser. The debutaniser strips out butane and provides a bottom product of gas condensate (C5+ stream).
The liquid products produced in the CATS terminal comprise commercial grade propane and butane and a C5+ stream.