Patent Application
20090007635
The present invention relates generally to gas analysis. More particularly, the present invention relates to drying of a gas for analysis.
During the drilling of a well, mud is circulated down hole to carry away drilling cuttings. On the surface the mud is pumped through a gas trap and a gas sample collected. The gas sample collected passes through what is known as a bubble jar where a liquid desiccant, such as a glycol absorbs moisture from the gas sample, thus drying the gas sample before it is sent to a gas analyzer.
Conventional bubble jars utilize a liquid container and an input tube lowered through the liquid desiccant to the bottom of the liquid container. An output tube is placed at the top of the liquid container. As moisture is absorbed from the gas sample, the level of desiccant rises, and if the bubble jar becomes overfilled, the liquid, absorbed from the sample, may pass through the output tube into the gas analyzer, causing false readings and/or damage to expensive equipment, such as the gas analyzer.
The invention relates apparatus and method for a floating bubble jar dryer, which includes a container floating in the liquid desiccant (for example glycol) on top of the input gas sample pipe. The gas flow pressure regulates the depth of the float in the drying liquid (for example glycol for water). Small holes at the bottom of the floating container disperse the gas in to the liquid where a diffusion process is absorbing the moisture from the gas sample.
The bubble jar dryer of the present invention provides increased protection for gas analyzer, with reduced maintenance and monitoring, both in frequency and degree of maintenance and monitoring, and may allow configurations which are smaller and lighter.
In one aspect, the present invention provides a bubble jar dryer for drying a gas stream, including a first drying section adapted to receive an initial level of liquid desiccant, an inlet adapted to receive the gas stream into the first drying section, a standpipe associated with the inlet, the standpipe adapted to extend above the initial level of liquid desiccant, a floating container movably received on the standpipe, the floating container having an interior and an exterior and an upper section and a lower section, and at least one passage between the interior and the exterior in the lower section, and an inlet adapted to direct the gas stream out of the first drying section, wherein the level of liquid desiccant rises as moisture is absorbed from the gas stream, and the floating container is adapted to at least partially float in proportion to the level of liquid desiccant.
In a further aspect, the present invention provides a method for drying a gas stream including providing the gas stream from an oil and gas well operation, providing a bubble jar dryer including a first drying section adapted to receive an initial level of liquid desiccant, an inlet adapted to receive the gas stream into the first drying section, a standpipe associated with the inlet, the standpipe adapted to extend above the initial level of liquid desiccant, a floating container moyably received on the standpipe, the floating container having an interior and an exterior and an upper section and a lower section, and at least one passage between the interior and the exterior in the lower section, and an inlet adapted to direct the gas stream out of the first drying section, wherein the level of liquid desiccant rises as moisture is absorbed from the gas stream, and the floating container is adapted to rise in proportion to the level of liquid desiccant, and passing the gas stream through the bubble jar dryer, analyzing the gas stream, and providing a log of gas stream analysis in correlation to the oil and gas well operation.
Other aspects and features of the present invention will become apparent to those skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.
Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:
The present invention provides an apparatus and process for at least partially removing moisture from a gas stream using a buoyant container and liquid desiccant for moisture absorption, for example a glycol to remove water from a gas stream.
Referring to
The first drying section 30 includes an inlet 50 for receiving the gas to be dried and an outlet 55 for delivering the gas. A level of a liquid desiccant 60, for example a liquid glycol, for example ethylene glycol, is maintained within the first drying section 30. A standpipe 70 is operatively associated with the inlet 50 and within a floating container 80.
Preferably, the liquid desiccant 60 is a low vapour pressure, non-combustible liquid.
The floating container 80 has an upper section 90 and a lower section 100 and an interior 110 and an exterior 120. The upper section 90 forms a vapour space 130, above the level of the liquid desiccant 60 and the lower section 100 forms a liquid space 140, below the level of the liquid desiccant 60. At least one passage 150 extends between the interior 110 and the exterior 120 of the floating container 80, within the liquid desiccant 60. Preferably, the at least one passage 150 comprises a plurality of small holes 160.
In operation, the bubble jar 10 receives a source of gas to be sampled, for example from a turbine gas trap as described in U.S. Pat. No. 6,389,878 to Zamfes.
The gas to be sampled enters the bubble jar 10 from the inlet 50, moisture is removed in at least the first drying section 30 (and preferably moisture is removed in the second drying section 40), and the gas is directed to a gas analyzer for analysis, for example to a differential gas detector as described in U.S. Pat. No. 6,276,190 to Zamfes or a gas chromatograph or other gas analyzer.
Within the first drying section 30, the gas flows out the standpipe 70 into the floating container 80. The gas flows through the vapour space 130, through the liquid space 140, dispersed through the plurality of small holes 160 into the liquid desiccant 60, through the level of liquid desiccant 60, and out of the first drying section 30, in this preferred case, to the second drying section 40, where the process is repeated. The inlet 50 and/or the outlet 55 may include an orifice or valve or other control means to control or regulate the flow and/or pressure of the gas.
The gas analyzer (not shown, downstream of the outlet 55) may include a vacuum pump or other suction means to help draw the gas from the bubble jar 10.
A filter, media, membrane, mesh, or other device may be installed within the vapour space 130 to reduce the amount of fluid droplets (if any) carried or entrained in flow. Preferably, such a device is a knitted metallic or non-metallic (e.g. plastic) wire mesh entrainment separator 170 situated between the floating container 80 and the outlet 55.
A pressure differential across the bubble jar 10 will lift the floating container 80 to a level proportional to its weight and the level of the liquid desiccant 60 in the housing 20 and the pressure differential. If the level of the liquid desiccant 60 reaches the top of the standpipe 70 the floating container 80 will push the excess of liquid out into inlet 50. This will help improve performance of the bubble jar 10 and help reduce liquid overflow that can plug or otherwise damage the gas analyzer.
In the preceding description, for purposes of explanation, numerous details are set forth in order to provide a thorough understanding of the embodiments of the invention. However, it will be apparent to one skilled in the art that these specific details are not required in order to practice the invention.
The above-described embodiments of the invention are intended to be examples only. Alterations, modifications and variations can be effected to the particular embodiments by those of skill in the art without departing from the scope of the invention, which is defined solely by the claims appended hereto.
This application claims the benefit of priority of U.S. Provisional Patent Application No. 60/929,355 filed Jun. 22, 2007, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 60929355 | Jun 2007 | US |
