JPS5973009A - Degassing apparatus - Google Patents

Abstract

PURPOSE:To provide an inexpensive degassing apparatus, by a method wherein the compressed gas itself of a compressor is bubbled and a part of the outlet gas of a cooler into which the emitting gas from the compressor is introduced is cooled by adiabatic expansion to remove the high molecular component in the gas in a liquid form. CONSTITUTION:A compressor 7 sucks natural gas containing a high molecular component from an arranged pipe 8 and emits the same to an emitting side arranged pipe 9 after compression to send the same to a cooler 10 in a compressed state, A part of the gas issued from the cooler 10 is sent to an arranged pipe 13 to be introduced into a tank 17. Because the tank 7 is opened to the atmospheric pressure, the gas is flowed to a nozzle 15 at a considerably high speed and, at this time, subjected to adiabatic expansion to be lowered in the temp. thereof. The gas is brought to a low temp. and high pressure state in the pipe 16 opened into the nozzle 15 and the high molecular component is brought to a saturated state in a gaseous form to be recovered as mist by a mist separator 19 while only the gas from which the high molecular component is removed is used in bubling seal oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for degassing seal oil of a turbo compressor that compresses gas containing high molecular weight hydrocarbon components such as natural gas.

Generally, the seal oil of a turbo compressor that handles natural gas etc. is partially exposed to the handled gas, and the high molecular weight components in the natural gas dissolve into the seal oil, lowering the viscosity of the oil and lowering the flash point of the oil. It also lowers the temperature
This will adversely affect the compressor.

Therefore, a device for degassing the high molecular weight components dissolved in the seal oil, that is, a degassing device is required. This degumming device is often implemented by blowing and bubbling an inert gas such as nitrogen into a seal oil tank containing high molecular weight components to degump the high molecular weight components in the oil. The reason why an inert gas is used is because the flash point temperature of the seal oil is low as mentioned above, and because a gas containing oxygen cannot be used to prevent oxidation of the oil. Also, if there is no inert gas such as nitrogen, reduce the pressure in the seal oil tank (vacuum).
Although methods have been implemented, they have the disadvantage of being very expensive.

The present invention was developed out of the need to perform degumming in the absence of an inert gas at a low cost, to the same extent as inert gas bubbling, without using a separate vacuum pump, as described above. be. For example, it is considered desirable to reduce the number of equipment required for natural gas compressors installed on offshore platforms and to perform in-house processing.

Figure 1 shows a conventional degutting device.
Nitrogen gas is supplied through piping 2 from a nitrogen gas supply device having a nitrogen tank 5, and is bubbled within the degassing tank 1.

Seal oil containing a high molecular weight gas component that has come into contact with the handling gas at pressure wJIa is transferred from piping 3 to degassing tank 1.
In the tank 1, the seal oil is heated by a heater 6, bubbled with inert gas C from the second pipe, and degushed. This oil returns to the seal oil device of the compressor through the pipe 4 and is again supplied for sealing the compressor.

FIG. 2 shows an embodiment of the present invention, in which the degassing tank 1 is the same as that in FIG. While nitrogen gas is supplied to the piping 2 in FIG. 1, in the present invention, the waste discharged from the compressor 7 is used for degassing. The outlet gas of a discharge cooler 10 provided on the discharge side of the compressor 7 is branched and introduced into a tank 14 via a pipe 13. The tank 14 is connected to a tank 17 by a relatively long nozzle 15, and the tank 17 is maintained at atmospheric pressure level by a vent pipe 18. On the other hand, a pipe 16 is opened at an appropriate position inside the nozzle 15, and the pipe 1G is connected to the miss 1 to the separator 19 outside the nozzle 15. Compressed gas flows from tank 14 to nozzle 1
The gas from which the high molecular weight components have been removed is passed through the pipe 1G opened in the interior of the pipe 1G, expands adiabatically, and is condensed into a mist. 2 and used for bubbling.

Next, the operation of the present invention will be explained with reference to the drawings. The compressor 7 sucks natural gas containing high molecular weight components from the pipe 8, and after compressing it, discharges it to the needle outlet side pipe 9 and sends it to the discharge cooler 10. 11
is the cooling water piping.

The gas leaving the cooler 10 flows out through the pipe 127J+i to the pipe 23 and is used, but a part of the gas is sent to the pipe 13 branched from the pipe 12 and introduced into the tank 14. . Since tank 17 is open to atmospheric pressure by vent pipe 18, gas flows at a considerably high velocity through nozzle 15 connecting both tanks 14,17. At this time, the waste expands rapidly, causing the gas to expand adiabatically and lowering its temperature. That is,
The temperature of the tank 14 is TOs, and the temperature inside the nozzle 15 is T2,
If the flow velocity is W2, then Cp (-ro -T2)-AW2 2 /
2Q However, Cp: constant pressure specific heat of gas, A: heat equivalent of work,
g: gravitational acceleration, and the temperature T2 inside the nozzle 15 decreases according to the speed W2.

A tube 1G is built in outside the nozzle 15, and the opening is the tank 14.
Therefore, the scum temperature at the opening of the tube 1e is To, the pressure is quite high based on the same principle as the full pressure port of the Pitot tube, and the flow rate can be relatively slow. The gas in the pipe 16 is cooled to the level T2 by passing through the nozzle 15, and the mist lever regulator 1 is cooled down to the level T2.
Sent to 9th. The high molecular weight components of the gas sent to the mist separator 19 reach a saturated state in gaseous form, are collected as mist by the mist separator, and are discharged from the discharge port 120. Therefore, only the gas from which high molecular weight components have been removed is sent to the pipe 2 via the heater 21 and the valve 22 and used for bubbling the seal oil. The temperature required for bubbling in the pipe 2 is controlled by the heater 21, and the pressure is controlled by the valve 22.
It is adjusted by

As understood from the above explanation, when bubbling the seal oil of a turbo compressor, degassing has conventionally been possible by simply heating the oil. However, when reusing seal oil from a compressor that contains residue containing high molecular weight components, simply heating it will remove some of the high molecular weight components, and eventually the inert gas used for degassing will cause bubbling. There is a method of degassing by heating and a method of degassing, and a method of reducing the pressure of the seal oil tank with a vacuum pump and heating it to remove the polymer components. The present invention does not employ any of these methods, but uses the compressed gas itself from the compressor for bubbling to perform degutting. [Seshime C Cold 7J] This is a degumming device that is equipped with a device that removes high molecular weight components contained in the gas by turning it into a liquid state, so it is possible to perform degumming without using an inert gas, and is an inexpensive method. This allows degutting of high molecular weight components.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of a conventional degumming device, and FIG. 2 is a side sectional view showing an embodiment of the degumming device for explaining the present invention. 1... Degassing tank, 5... Nitrogen cylinder. 6... Heating tube, 7... Compressor, 10... Cooler, 14.17... Tank, 15... Nozzle, 16...
...Pipe, 19...Mist separator.

Claims (1)

[Claims] This device degushes the seal oil of a turbo compressor by bubbling. It adiabatically expands and cools a part of the exhaust gas from a cooler placed on the discharge side of the compressor, and removes high molecular weight components contained in the gas. A degassing device comprising a device for liquefying and removing high molecular weight components, and using the gas after removing high molecular weight components by the device for bubbling.