Gas separation: processes – Degasification of liquid
Patent
1998-09-22
2000-10-31
Simmons, David A.
Gas separation: processes
Degasification of liquid
95243, 95248, 95260, 96195, 96196, 96204, B01D 1900
Patent
active
061396060
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to the pumping a fluid medium, such as a liquid or suspension, containing a gas. More particularly, the present invention relates to a method and apparatus for removing the gas from the medium in a pump.
BACKGROUND OF THE INVENTION
When pumping a gas-containing medium, such as a pulp suspension containing air or another gas, by means of centrifugal pumps, the pumping process is rendered more difficult by the gas being collected centrally in the pump in front of the impeller. A gas bubble formed in that manner thus increases in size until the pump ceases to operate.
In order to eliminate this problem, centrifugal pumps have been designed with impellers, which are provided with openings for evacuating the gas flow from the central portion of the pump and further through evacuation channels out of the pump. According to known techniques, vacuum pumps are generally used for evacuating the gas. The gas to be evacuated is therefore required to be practically free of impurities so as to limit the wear on the vacuum pumps.
Particularly during the pumping of pulp suspensions problems arise by the pulp following along with the gas. This applies particularly to the pumping of pulp at low concentrations. The pulp concentration is normally in the range of from 1 to 20%. A further problem is that the pulp suspension flowing through in this manner cannot be pumped back to the container, to which the pulp pump is connected. Furthermore, normal vacuum pumps cannot manage high temperatures.
One object of the present invention is therefore to solve the aforementioned problems by using an ejector for evacuating the gas from the medium in the pump.
SUMMARY OF THE INVENTION
In accordance with the present invention, this and other objects have now been realized by the discovery of a method for degassing a gas-containing fluid medium in a container which comprises pumping the fluid medium from the container to provide a pumped fluid medium, passing at least a portion of the pumped fluid medium through the suction side of an ejector for removing the gas from the fluid medium, diverting a separate portion of the pumped fluid medium to drive the ejector, and returning the separate portion of the pumped fluid medium exiting from the ejector to the container. Preferably, the pump comprises a centrifugal pump. More preferably, the fluid medium comprises a liquor from a pulp manufacturing process. In a preferred embodiment, the method includes further processing of the liquor in a pulp manufacturing process.
In accordance with the present invention, apparatus has also been discovered for degassing a gas-containing fluid medium comprising a container for the gas-containing fluid medium, a centrifugal pump for pumping the gas-containing fluid medium from the container, an ejector including a suction side, an ejector inlet for a drive fluid, and an ejector outlet for the drive fluid, whereby at least a portion of the pumped fluid medium is fed to the suction side of the ejector for removing the gas therefrom, a diversion conduit for diverting a separate portion of the pumped fluid medium from the centrifugal pump to the ejector inlet, and a return conduit for returning the separate portion of the fluid medium from the ejector outlet to the container.
In accordance with a preferred embodiment of the apparatus of the present invention, the container includes a degassing valve for eliminating gas from the fluid medium returned to the container.
In accordance with another embodiment of the apparatus of the present invention, the centrifugal pump is located downstream of the container, and the apparatus includes a glass gauge for filtrate from a press located between the container and the centrifugal pump.
In accordance with the present invention, by diverting a partial flow of the pumped medium after the pump, i.e. in the pressure line of the pump, and causing this partial flow to drive an ejector, the suction side of which is coupled to the evacuation channels of the pump, the gas ca
REFERENCES:
patent: 3481113 (1969-12-01), Burnham, Jr.
patent: 3517487 (1970-06-01), Burnham, Jr.
patent: 3616599 (1971-11-01), Burnham, Jr.
patent: 3769779 (1973-11-01), Liljestrand
patent: 3898061 (1975-08-01), Brunato
patent: 4097249 (1978-06-01), Phillips et al.
patent: 4097253 (1978-06-01), Phillips et al.
patent: 4108619 (1978-08-01), Phillips et al.
patent: 4410337 (1983-10-01), Gullichsen et al.
patent: 4435193 (1984-03-01), Gullichsen et al.
patent: 4516987 (1985-05-01), Niggemann
patent: 4645518 (1987-02-01), Roffelsen
Forslund Kjell
Kotkaniemi Leo
Pham Minh-Chau T.
Simmons David A.
Valmet Fibertech Aktiebolag
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