A horizontal decanter centrifuge for enhanced recovery of drilling mud from drilling mud solids. Oilfield decanters will always suffer some drilling mud losses because they can only achieve a certain effectiveness with respect to solids dryness. The embodiment describes a process to mitigate the financial burden of drilling mud losses by adding a less expensive sacrificial fluid to take the place of drilling mud in the solids phase. A process and apparatus for drilling mud displacement is described including flowing the drilling mud into a horizontal decanter centrifuge, wherein the stresses imposed within the decanter act to force a sacrificial fluid to displace the drilling mud. The embodiment also describes a process wherein vapours or mist are prevented from escaping and becoming airborne into the external atmosphere.

A horizontal decanter centrifuge for enhanced recovery of drilling mud from drilling mud solids. Oilfield decanters will always suffer some drilling mud losses because they can only achieve a certain effectiveness with respect to solids dryness. The embodiment describes a process to mitigate the financial burden of drilling mud losses by adding a less expensive sacrificial fluid to take the place of drilling mud in the solids phase. A process and apparatus for drilling mud displacement is described including flowing the drilling mud into a horizontal decanter centrifuge, wherein the stresses imposed within the decanter act to force a sacrificial fluid to displace the drilling mud. The embodiment also describes a process wherein vapours or mist are prevented from escaping and becoming airborne into the external atmosphere.

Disclosed is a continuous centrifugal dewatering device including an external case having an internal space, a feed supply pipe to which a slurry as a mixture of a solid and a liquid is supplied, a basket provided inside the external case, a plurality of holes formed in the basket, a pusher plate provided inside the basket and configured to discharge a slurry cake attached to an inner circumferential surface of the basket to the outside of the external case, a non-contact seal configured to prevent the first gas from flowing into a space between the external case and the basket, and a gas inlet to which a second gas, which flows in a reverse direction with respect to a flow direction of the first gas flowing to the space between the external case and the basket, is supplied.

A method for determining if air is trapped within a centrifugal separator, the separator including a stationary frame, a rotatable assembly, a drive unit for rotating the rotatable assembly relative the frame around an axis of rotation, a feed inlet for supply of a liquid mixture to be separated, a first liquid outlet for discharge of a separated liquid phase and a second liquid outlet for discharge of a heavy phase having a density that is higher than said liquid phase. The rotatable assembly includes a rotor casing enclosing a separation space in which a stack of separation discs is arranged to rotate around a vertical axis of rotation. The method includes closing one of the first and second liquid outlets and restricting the flow from the other outlet; supplying feed to the feed inlet and measuring the flow to the feed inlet and the flow from the restricted outlet; comparing the flow as a function of time between feed inlet and the restricted outlet; and determining that air is trapped within the centrifugal separator if the measured flow as a function of time flow deviates between feed inlet and the restricted outlet.

A method of operating a centrifugal separator is provided. The method includes supplying a liquid mixture to be separated to the inlet of the centrifugal separator, separating the liquid mixture into at least one separated liquid component and a separated sludge component, discharging at least one separated liquid component from at least one liquid outlet of the centrifuge rotor, removing gas from a space surrounding a centrifuge rotor of the separator, to obtain a sub-atmospheric pressure in the space, and discharging a separated sludge component from at least one sludge outlet arranged at a periphery of the centrifuge rotor to the space which is delimited by a frame, wherein the discharging is performed when the sub-atmospheric pressure in the space surrounding the centrifuge rotor is within a preset pressure interval ΔP.

A method of operating a centrifugal separator is provided. The method includes supplying a liquid mixture to be separated to the inlet of the centrifugal separator, separating the liquid mixture into at least one separated liquid component and a separated sludge component, discharging at least one separated liquid component from at least one liquid outlet of the centrifuge rotor, removing gas from a space surrounding a centrifuge rotor of the separator, to obtain a sub-atmospheric pressure in the space, and discharging a separated sludge component from at least one sludge outlet arranged at a periphery of the centrifuge rotor to the space which is delimited by a frame, wherein the discharging is performed when the sub-atmospheric pressure in the space surrounding the centrifuge rotor is within a preset pressure interval ΔP.

A liquid handling device having an axis of rotation about which the device can be rotated to drive liquid flow. The device includes a vented upstream chamber having an outlet port and an unvented chamber including an inlet port to receive liquid from the outlet port of the upstream chamber and an outlet port radially outward the inlet port. The device further includes a vented downstream chamber having an inlet port to receive liquid from the outlet port of the unvented chamber. A downstream conduit connects the outlet port of the unvented chamber to the inlet port of the downstream chamber and includes a bend radially inward of the outlet port of the unvented chamber. An upstream conduit connects the outlet port of the upstream chamber to the inlet port of the unvented chamber.

A liquid handling device having an axis of rotation about which the device can be rotated to drive liquid flow. The device includes a vented upstream chamber having an outlet port and an unvented chamber including an inlet port to receive liquid from the outlet port of the upstream chamber and an outlet port radially outward the inlet port. The device further includes a vented downstream chamber having an inlet port to receive liquid from the outlet port of the unvented chamber. A downstream conduit connects the outlet port of the unvented chamber to the inlet port of the downstream chamber and includes a bend radially inward of the outlet port of the unvented chamber. An upstream conduit connects the outlet port of the upstream chamber to the inlet port of the unvented chamber.

The invention relates to a centrifugal separator comprising a casing which delimits and seals off a space in which a rotor is arranged. The rotor forms a separation space which is sealed or isolated from the space, and in which separation space centrifugal separation of a higher density and a lower density component from a fluid takes place. An inlet extends into the rotor for introducing fluid to the separation space, and a first outlet extends from the rotor for discharge of a component separated from the fluid. The space is connected to a pump device which is arranged to remove gas, thereby maintaining negative pressure in said space. The rotor comprises at least one second outlet extending from the separation space to the space for discharge of at least one higher density component separated from the fluid. The invention also relates to a method in such a centrifugal separator.

The invention relates to a centrifugal separator comprising a casing which delimits and seals off a space in which a rotor is arranged. The rotor forms a separation space which is sealed or isolated from the space, and in which separation space centrifugal separation of a higher density and a lower density component from a fluid takes place. An inlet extends into the rotor for introducing fluid to the separation space, and a first outlet extends from the rotor for discharge of a component separated from the fluid. The space is connected to a pump device which is arranged to remove gas, thereby maintaining negative pressure in said space. The rotor comprises at least one second outlet extending from the separation space to the space for discharge of at least one higher density component separated from the fluid. The invention also relates to a method in such a centrifugal separator.