Costain has been selected for an eight-month study into removing heavy hydrocarbons from natural gas.
The study was awarded by the GPA Midstream Association, which is based in Tulsa, Oklahoma.
“Shale gas production means that US natural gas production has increased greatly in recent years. Giant plants (typically costing many hundreds of millions of dollars) in Texas and Louisiana can produce several million tonnes per annum. These are now starting operation, with more to follow,” said Adrian Finn, process technology manager, Costain.
“In order for the gas to be transported, it is cooled to below -160°C so that it liquefies and occupies only 1/600th of its original volume. It is then carried on massive tankers to export markets including the UK.”
Finn added: “The natural gas feeding such liquefaction plants (and proposed smaller ones) has already been processed for pipeline transportation and for use as fuel. However, the processing requirements for liquefaction are more stringent and any components that may freeze must be removed.
“This includes water and carbon dioxide for which proven technologies exist. But it also includes ‘heavy hydrocarbons’ which, though normally present in minute quantities, can freeze and block equipment and so must be removed.”
The next step for the project is to identify and assess commercial technologies for removing components that could freeze.