Patent ID: 9394764
Filing Date: 2016-07-19
CPC Classification: E21B,F01D,F02C,F03B,F03G,F05B,F05D,F17D,Y02B,Y02E

Claim Text:
1. An apparatus for reducing the pressure of a fluid comprising a natural gas, water, and solid residues, said fluid being available at an extraction pressure at a wellhead of a natural gas field and for recovering energy directly from said natural gas at said wellhead, said apparatus comprising: a vertical elongated container having an inlet nozzle for said fluid for connection with said wellhead and an outlet nozzle for a treated natural gas, said outlet nozzle above said inlet nozzle in said vertical elongated container; a cyclone centrifugal separation stage arranged in said vertical elongated container at said inlet nozzle, said cyclone centrifugal separation stage configured for separating said water and solid residues from said natural gas of said fluid, an inertial separation stage arranged in said vertical elongated container at said outlet nozzle for separating liquid droplets and mist from the gas, a gas-conditioning means arranged downstream of said outlet nozzle and configured to prevent a formation of ice in said natural gas during a subsequent expansion in a rotor, an energy recovery expansion device arranged downstream of said gas-conditioning means for expanding said natural gas until a use pressure is reached, said energy recovery expansion device having said rotor rotatably arranged about an own axis and a stator, and a gas passageway defined between said rotor and said stator; an electric power generator that is mechanically connected to said rotor of said energy recovery expansion device, so that said electric power generator can generate an electric power when a stream of said natural gas exiting from said wellhead is conveyed in said passageway of said energy recovery expansion device, thus causing a rotation of said rotor and causing the gas to expand; and an electric power extraction means for extracting said electric power generated by said electric power generator.