Rotary kinetic fluid motors or pumps – Including means for handling portion separated from working... – Moisture or liquid separated from gaseous working fluid...
Reexamination Certificate
1999-01-28
2001-08-14
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Including means for handling portion separated from working...
Moisture or liquid separated from gaseous working fluid...
C415S169400, C415S199100
Reexamination Certificate
active
06273674
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a wet gas compressor comprising a first compression stage designed to prevent erosion by liquid droplets at the inlet of the impeller blades and to perform separation of the gas phase and of the liquid phase.
The compressor can comprise downstream several stages similar to the first stage or conventional impellers designed for compression of a dry gas.
The invention is intended for compression of a wet gas, i.e. a two-phase mixture whose gas and liquid volume flow rate ratio in the input conditions of the device (GLR) is higher than about 20.
The invention can find applications for production of a wet gas essentially consisting of hydrocarbons without prior gas processing, as well as in any process in the field of refining or chemistry using a gas compressor preceded by a sieve droplet separator or other.
BACKGROUND OF THE INVENTION
Various multiphase pump types allow compression of a two-phase mixture. However, rotodynamic type machines are limited to GLR ratios hardly higher than 20, and positive-displacement machines are relatively bulky for compression of a wet gas.
It is difficult to use conventional, centrifugal or axial gas compressors to compress a gaseous fluid comprising a liquid phase because of the erosion due to the liquid droplets on the blades of the impellers, of the embrittlement of the blades and of the rotor unbalance resulting therefrom.
A first primary separation stage (working under the action of the terrestrial gravity) is therefore more generally used upstream from a gas compressor for rough separation of the gas and of the liquid, then a second, secondary (for example sieve) separation stage is used for finer separation of the droplets contained in the gas. This layout also requires a single-phase pump for transfer of the liquid from the input pressure to the discharge pressure. These equipments are heavy and bulky.
The volume of the static separators can be reduced while maintaining the same degree of separation of the liquid droplets and of the gas, by generating high centrifugal forces produced only by means of the energy of the fluid (without external energy supply). This is, for example, the working principle of cyclone separators.
The volume of the separators can be reduced further yet, while maintaining the same degree of separation of the liquid droplets and of the gas, by generating very high centrifugal forces produced from an external energy (separator referred to as dynamic separator). It is for example the working principle of the dynamic separator described in the Bertin patent WO-87/03,051. While this separator has the advantage of being relatively compact, it constitutes a second rotating machine when mounted outside the compressor, and it reduces the number of impellers of the compressor by about 30% when mounted inside the compressor.
SUMMARY OF THE INVENTION
The object of the invention is a wet gas compression device that overcomes the drawbacks of the prior art and notably limits erosion caused by droplets at the stage inlet.
The wet gas compressor according to the invention comprises one or more compression stages suited to separate the liquid phase from the gas phase, to limit erosion due to droplets at the stage inlet and to compress at least the gas phase, the liquid phase being pressurized.
The invention also consists in associating a compression section suited to separate the liquid phase and the gas phase with a compression section suited for a dry gas.
The invention is intended for compression of a wet gas, i.e. a two-phase mixture whose gas and liquid volume flow rate ratio (GLR) in the input conditions of the device is higher than about 20.
What is understood to be a <<dry gas >> hereafter is a gas containing liquid droplets whose diameter is below 10 microns and consequently generating only a very low erosion at the level of the impeller blades.
The present invention relates to a wet gas compression device, said gas comprising a liquid phase and a gas phase, including:
at least one inlet pipe for said wet gas,
at least one outlet pipe for the compressed gas,
a shaft,
several compression stages,
at least one compression stage suited to limit erosion and to separate the liquid phase from the gas phase,
one or more pipes designed for discharge of an essentially liquid phase resulting at least partly from the separation performed in a suitable compression stage.
The device is characterized in that the suitable compression stage comprises for example an inlet line, an impeller and an outlet line, the inlet and outlet lines allowing separation of the liquid phase and of the gas phase.
The inlet line comprises for example two substantially rectilinear and parallel walls, the walls being respectively extended by two curved walls having a radius of curvature selected to generate a centrifugal effect and the wall is provided with a means allowing passage of the liquid from the outer wall to the inner wall.
The outlet line comprises for example a return channel including at least one collecting channel, and at least one means allowing passage of the liquid into the collecting channel, the means being placed on one of the walls at the diffuser outlet.
The device can comprise an inlet line and an outlet line having the aforementioned characteristics.
At nominal delivery, the inlet angle &agr;
2
of the impeller blades is approximately equal to the angle &agr;
1
of the relative gas velocity V
r,g
and, on the other hand, the angle &bgr; of the absolute gas velocity V
a,g
, with the driving velocity V
e
, is so determined that the relative velocity of the droplets V
r,l
, is at least twice as low as that of the gas V
r,g
.
At least one of the suitable compression stages can be the inlet stage of the compression device.
The device can comprise at least one means for collecting the essentially liquid phases separated in the suitable compression stage(s), the collection means being connected to the pipes designed for discharge of the essentially liquid phase and to the outlet pipe.
The present invention also relates to a wet gas compression system. It is characterized in that it comprises at least one compression device and at least one device allowing partial separation of the liquid phase, upstream from the compression device.
Using the compression device or the compression system will be advantageous for production of a wet gas in the petroleum or refining field.
The compressor according to the invention notably allows to:
reduce the power absorbed and the number of machines in comparison with production by means of rotodynamic multiphase pumps,
reduce the bulk and weight in comparison with production by means of positive-displacement multiphase pumps,
reduce the number of equipments in comparison with conventional production comprising single-phase separators, compressors and pumps,
use a larger number of compression impellers in comparison with a wet gas compressor including a dynamic separator in the compressor, as described in patent WO-87/03,051.
REFERENCES:
patent: 2332614 (1943-10-01), Swearingen
patent: 3104964 (1963-09-01), Craft
patent: 4059364 (1977-11-01), Andersen
patent: 4938661 (1990-07-01), Kobayashi et al.
patent: 4961260 (1990-10-01), Ferri et al.
patent: 5993151 (1999-11-01), Paulsen et al.
patent: 235397 (1911-06-01), None
patent: 2574871 (1986-06-01), None
patent: 2589957 (1987-05-01), None
patent: 2273958 (1994-07-01), None
Antonelli Terry Stout & Kraus LLP
Institut Francais du Pe'trole
Look Edward K.
McAleenan James M
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