Abstract: A method of raising the pressure of a natural gas stream (9) on an oil or gas producing installation (1) comprises using an existing high pressure gas stream (13) at the installation to drive the turbine (12) of a turbo-compressor unit (10). It is common on oil and gas producing installations to require the pressure of a gas stream to be increased by a small amount, e.g. to allow flare gas to be fed to the production gas train thereby avoiding flaring. This system may replace the current practice of using ejectors for this purpose since ejectors are very inefficient. However, it can be advantageous to feed the output of the turbine side (12) of the turbo-compressor (10) to an ejector which can give a small pre-boost to the low pressure natural gas (9) before it enters the compressor side (11) of the turbo-compressor (10). (FIG. 2).

Abstract: A method of raising the pressure of a natural gas stream (9) on an oil or gas producing installation (1) comprises using an existing high pressure gas stream (13) at the installation to drive the turbine (12) of a turbo-compressor unit (10). It is common on oil and gas producing installations to require the pressure of a gas stream to be increased by a small amount, e.g. to allow flare gas to be fed to the production gas train thereby avoiding flaring. This system may replace the current practice of using ejectors for this purpose since ejectors are very inefficient. However, it can be advantageous to feed the output of the turbine side (12) of the turbo-compressor (10) to an ejector which can give a small pre-boost to the low pressure natural gas (9) before it enters the compressor side (11) of the turbo-compressor (10). (FIG.