Abstract: A mixed refrigerant stream (10) comprising a first mixed refrigerant is passed through one or more heat exchangers (12) to provide a cooled mixed refrigerant stream (20). At least a fraction of a cooling stream (30) comprising a second mixed refrigerant is expanded (14) to provide one or more expanded cooling streams (40a), at least one of which may be passed through one or more of the heat exchangers (12), to cool the mixed refrigerant stream (10) thereby providing the cooled mixed refrigerant stream (20) which is used to cool (22) a hydrocarbon stream (70). The temperature (T1) and the flow (F1) of at least part of the cooled mixed refrigerant stream (20) is monitored, and the flow (F2) of the cooling stream (30) is controlled using the flow F1 and the temperature T1.

Abstract: Method and apparatus for controlling one or more first compressors (12), through which a compressor feed stream (10) is passed. At least one throttling valve (32) is provided downstream of a compressor recycle line (22), which is provided around the or each first compressor (12) and includes an in-line first recycle valve (24). Sometimes, at least a fraction of the compressor feed stream (10) is selectively allowed to bypass the or each first compressor (12) and the at least one throttling valve, via a bypass line (60). At least one of the throttling valves (32) is automatically controlled using the measurement values of at least one pressure and at least one flow of the group consisting of: the pressure (P1) of the compressor feed stream (10), the flow (F1) of the compressor feed stream (10), the pressure (P2) of the first compressed stream (20) and the flow (F2) of the first compressed stream (20). A first compressor controlled this way may be used in a method of cooling an initial hydrocarbon stream (100).

Abstract: Method and apparatus for treating a mixed hydrocarbon feed stream (10), such as a natural gas stream. The mixed hydrocarbon feed stream (10) is expanded into a mixed-phase hydrocarbon stream (20), which is separated the to provide at least a light overhead stream (30) and a heavy bottom stream (50). The light overhead stream (30) is compressed in one or more first compressors (16) to provide one or more first compressed light streams (40) and further compressed in one or more second compressors (22) to provide one or more further compressed light streams (60). One or more first compressor recycle lines (42) extend around the or each first compressor (16), and one or more second compressor recycle lines (32) having one or more in-line coolers (34) extend around the or each second compressor (22). The method and apparatus may be used in a method of cooling an initial hydrocarbon stream (100).

Abstract: Method and apparatus for controlling one or more first compressors (12), through which a compressor feed stream (10) is passed. At least one throttling valve (32) is provided downstream of a compressor recycle line (22), which is provided around the or each first compressor (12) and includes an in-line first recycle valve (24). Sometimes, at least a fraction of the compressor feed stream (10) is selectively allowed to bypass the or each first compressor (12) and the at least one throttling valve, via a bypass line (60). At least one of the throttling valves (32) is automatically controlled using the measurement values of at least one pressure and at least one flow of the group consisting of: the pressure (P1) of the compressor feed stream (10), the flow (F1) of the compressor feed stream (10), the pressure (P2) of the first compressed stream (20) and the flow (F2) of the first compressed stream (20). A first compressor controlled this way may be used in a method of cooling an initial hydrocarbon stream (100).

Abstract: A mixed refrigerant stream (10) comprising a first mixed refrigerant is passed through one or more heat exchangers (12) to provide a cooled mixed refrigerant stream (20). At least a fraction of a cooling stream (30) comprising a second mixed refrigerant is expanded (14) to provide one or more expanded cooling streams (40a), at least one of which may be passed through one or more of the heat exchangers (12), to cool the mixed refrigerant stream (10) thereby providing the cooled mixed refrigerant stream (20) which is used to cool (22) a hydrocarbon stream (70). The temperature (T1) and the flow (F1) of at least part of the cooled mixed refrigerant stream (20) is monitored, and the flow (F2) of the cooling stream (30) is controlled using the flow F1 and the temperature T1.

Abstract: A system (1) for separating a fluid stream (2) comprising gas, a light liquid and a heavy liquid, the system comprising a separation vessel (5) that is arranged to define a downwardly extending separation space and comprises a downwardly sloping tube (8), the separation space having an inlet (10) for the fluid stream at a first height, an outlet (20) for heavy liquid at a second height below the first height, an outlet (30) for light liquid at a third height between the first and second heights, an outlet (70) for gas above all outlets for liquid, wherein a further outlet (51, 56) for light liquid is provided at a fourth height between the first and third heights, and wherein at least the outlet at the third height is provided with a control valve (33) that is operative to open and close in dependence of the type of liquid in the pipes at that level, and a method of separating a fluid stream comprising gas, a light liquid and a heavy liquid in such a system, wherein an indication of height of an interface bet

Abstract: A system (1) for separating a fluid stream (2) comprising gas, a light liquid and a heavy liquid, the system comprising a separation vessel (5) that is arranged to define a downwardly extending separation space and comprises a downwardly sloping tube (8), the separation space having an inlet (10) for the fluid stream at a first height, an outlet (20) for heavy liquid at a second height below the first height, an outlet (30) for light liquid at a third height between the first and second heights, an outlet (70) for gas above all outlets for liquid, wherein a further outlet (51, 56) for light liquid is provided at a fourth height between the first and third heights, and wherein at least the outlet at the third height is provided with a control valve (33) that is operative to open and close in dependence of the type of liquid in the pipes at that level, and a method of separating a fluid stream comprising gas, a light liquid and a heavy liquid in such a system, wherein an indication of height of an interface bet