JPH02264199A - Heat reserving method for shaft seal device of low temperature blower - Google Patents

Abstract

PURPOSE:To reduce cost of equipment in a lubricating system of a low temperature blower by utilizing lubricating oil for heat reserving of a shaft seal device, and by returning and recirculating the lubricating oil cooled during heat reserving process of the shaft seal device. CONSTITUTION:Lubricating oil heated upto comparatively high temperature during steady-state running is supplied into an oil box 5 from an oil inlet port 6 of the oil box 5 through a piping 9 by using an oil pump 8. Consequently, a circumference of a shaft seal device 3 is heated. The lubricating oil to be discharged from an outlet port 10 of the oil box 5 is cooled by an impeller 2 and a shaft 1 cooled by low temperature LNG recycle gas, and the oil temperature drops and becomes suitable for lubrication in a lubricating part 12. The lubricating oil cooled by heat exchange in the oil box 5 is heated again upto higher temperature through lubrication in the lubricating part 12 and is returned to a lubricating oil tank 7. Consequently, it is not necessary to preheat lubricating oil flowing into the oil box 5 by using any external heat source and, in addition, to cool the lubricating oil flowing into the lubricating part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for keeping a shaft seal device of a low-temperature blower warm.

[Prior Art] In a lithium gas blower for low-temperature gas such as liquefied natural gas (LNG), as shown in Fig. 3, a carbon ring d is attached to the bearing of a shaft C on which an impeller b rotating inside a casing a is mounted. A shaft sealing device e is provided, and combustible LNG is sealed by blowing high-pressure dry nitrogen gas into the shaft sealing device e and pressurizing it.

However, the LNG return gas is -160 to -150℃
Since the temperature is low, the impeller b is cooled, and in turn the shaft C and the shaft seal device e are cooled by cold heat conduction, and moisture in the air condenses and forms frost around the shaft seal device e. If the amount of frost becomes large, the function of the shaft sealing device e will be impaired, and the journal bearing f will also be adversely affected. Therefore, it is desirable to maintain the shaft seal device e at a temperature of 10° C. or higher.

Therefore, conventionally, an annular steam box 9 is disposed around the shaft sealing device e, and high-temperature steam is supplied into the steam box 9 to warm it, thereby preventing overcooling and frost formation.

[The problem to be solved by the invention] However, when heating with high-temperature steam, there are the following problems.

(i) Since high-temperature steam is required as a heat source, piping for supplying high-temperature steam is required.

(n) If the plant does not have a high-temperature steam source, this may not be possible or a new high-temperature steam source must be installed.

0 When using high-temperature steam, if the flow rate is too high, the shaft sealing device e may be overheated, so temperature control was necessary.

(c) When water vapor is used, it is condensed into water, which is further cooled and may freeze in the steam box Q when the return gas blower is stopped.

If it freezes in the steam box q, the next time the return gas blower is operated, high-temperature steam will not pass through the steam box 9, making it impossible to prevent the shaft seal device from being overcooled.

The present invention has been made for the purpose of eliminating the problems of the above-mentioned conventional heat retention method for a shaft seal device.

[Means for Solving the Problems] The present invention uses lubricating oil from a lubricating oil system of low-temperature blower equipment to keep a shaft seal device warm, and uses the cooled lubricant oil when keeping the shaft seal device warm to lubricate the shaft seal device. This invention relates to a method for keeping a shaft seal device of a low temperature blower warm, which is characterized by circulating the oil back into the oil system.

[Function] By using high-temperature lubricating oil derived from the lubricating oil system provided in the low-temperature blower equipment instead of high-temperature steam to keep the shaft seal device warm, a high-temperature steam source and its piping are unnecessary, reducing equipment costs. It is possible to safely and reliably keep the shaft seal device warm.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an apparatus used to carry out the present invention,
1 is the shaft of a low-temperature blower, such as an LNG recycle blower; 2
3 is an impeller, 3 is a sealing device, 4 is a labyrinth ring, an annular oil box 5 is provided around the outer periphery of the shaft sealing device 3, and a lubricating oil tank 7 attached to the low-temperature blower is installed in the oil port 6 of the oil box 5. Oil pump 8 derived from
A piping 9 having a lubrication oil tank 7 is connected thereto so that the lubricating oil in the lubricating oil tank 7 can be supplied to the oil box 5.

The oil hox 5 is provided with an oil outlet 10 to discharge the lubricating oil cooled by heat exchange within the oil hox 5, and after passing the discharged lubricating oil through a filter 11, the bearing of the low-temperature blower, The lubricating oil is sent to a lubricating part 12 such as a gear to be lubricated, and then returned to a lubricating oil tank 7.

The temperature of the lubricating oil in the lubricating oil tank γ is low before or immediately after the operation of the low-temperature blower, so it has a high viscosity and poor fluidity. The ura pump 8 is operated in advance to a suitable temperature, and the lubricating oil is warmed by the heat generated by the ura pump 8.

In addition, the temperature of the lubricating oil that passes through the lubricating parts 12 such as bearings and gears of the low-temperature blower rises, so the temperature of the lubricating oil in the lubricating oil tank 7 gradually rises. It was necessary to cool the oil using an oil cooler or the like and then send it to the lubricating section 12. Therefore, conventionally, the low-temperature blower had to be equipped with a large oil cooler.

However, according to the present invention, lubricating oil that has reached a relatively high temperature during steady operation is supplied into the oil box 5 from the oil port 6 of the oil box 5 via the pipe 9 by the oil pump 8. The surroundings of the lubricating part 12 are warmed, and the lubricating oil discharged from the oil outlet 10 of the oil box 5 is cooled by the cold heat of the LNG recycle gas transmitted from the impeller 2 and the shaft 1, and its temperature decreases.
The temperature is suitable for lubrication.

The lubricating oil, which has been cooled by heat exchange in the oil box 5, lubricates the lubricating part 12, rises in temperature again, and returns to the lubricating oil tank 7.

In this way, during steady operation of the low-temperature blower, the lubricating oil heated in the lubricating part 12 is used to keep the sealing device 3 warm, and the lubricating oil cooled in the oil box 5 is used to lubricate the lubricating part 12. There is no need to heat the lubricating oil entering the oil box 5 by introducing heat from the outside, and there is no need to cool the lubricating oil entering the lubricating section 12, or only a slight cooling is required.

FIG. 2 is another example of the apparatus used to carry out the present invention,
In a configuration substantially similar to the example shown in FIG. The lubricating oil is also connected to the oil box 5 and the lubricating part in parallel, and the return pipe 14 from the oil outlet 1o of the oil box 5 and the bearing part 1
The return pipes 15 and 16 of the third and other lubricating parts are merged together and returned to the lubricating oil tank 7. In the figure, 17 is an oil cooler, 18 is a motor, 19 is a speed increaser, and 20 is a nitrogen gas supply pipe, and the same reference numerals as in FIG. 1 indicate the same parts.

At the time of startup, the lubricating oil in the lubricating oil tank 7 is heated by a heating device, and after the temperature has been raised by 1 to the temperature at which lubrication is possible, the lubricating oil is pumped through the piping 9 by the oil pump 8 to the speed increaser 19 and the bearing part 13. etc. and the oil box 5. A part of the lubricating oil rises in temperature in the lubricating part, but the other part rises in temperature in the oil hox 5.
Since the LNG return gas is cooled by conduction of cold heat within the tank, the overall temperature increases only slightly when these return ports are merged.

Therefore, the temperature of the lubricating oil in the lubricating oil tank 7 increases only a small amount even when the engine is operated for a long time, so there is little need to operate the oil cooler 17.

If the steady state of operation continues for a long time, the temperature of the lubricating oil gradually rises by -1 and the temperature in the return pipe 14 reaches about 58°C, so the oil cooler 17 is operated to cool it down to about 49°C.

Below-1], the lubricating part of the lubricating oil and the oil box 5
By setting the flow rate ratio to a predetermined ratio, the lubricating oil can be circulated at an optimal temperature, and external cooling or heating can be unnecessary or minimized.

Note that the method of keeping the shaft seal device of a low-temperature blower warm according to the present invention is not limited to the above-mentioned embodiments, and the method of keeping the shaft seal device warm by supplying lubricating oil whose temperature has increased through the lubricating section to the oil box. Of course, various changes can be made without departing from the spirit of the present invention, such as lowering the temperature of the lubricating oil and sending it to the lubricating section again.

[Effects of the Invention] As described above, the heat retention method for a shaft sill device of a low-temperature blower according to the present invention exhibits various excellent effects as described below.

(D) An annular oil box is installed around the shaft sealing device of the low-temperature blower, and relatively high-temperature lubricating oil is supplied to the oil box from the lubricating oil system provided in the low-temperature blower equipment. Compared to thermal insulation, high-temperature steam supply equipment is not required, and equipment costs can be significantly reduced.

<n> When keeping the shaft seal device warm in the oil box, the lubricating oil cooled by heat exchange is sent to the lubricating part, so an oil cooler was previously required to cool the lubricating oil whose temperature rose due to lubrication of the lubricating part. However, these can be made unnecessary or downsized, and equipment costs can be reduced.

[Phase] Using the lubricating oil system equipped with low-temperature blower equipment, the cold heat in the shaft seal part is used to cool the lubricating oil that has risen in temperature in the lubricating part, and the heat generated in the lubricating part is used to keep the shaft seal part warm. Since it is used for this purpose, it is extremely rational, and the supply and discharge of heat from the outside can be kept to the minimum necessary, making it extremely effective as an energy saving measure.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of an example of the device used to carry out the method of the present invention, Fig. 2 is an explanatory diagram of another example of the device used to carry out the method of the present invention, and Fig. 3 is a conventional shaft seal. FIG. 3 is an explanatory diagram of the heat insulation equipment of the device. 3 is a shaft, 3 is a shaft seal device, 5 is an oil box, 9 is piping, 12 is a lubricating section, and 17 is an oil cooler.

Claims (1)

[Claims] 1) The lubricating oil from the lubricating oil system of the low-temperature blower equipment is used to keep the shaft seal device warm, and the cooled lubricating oil when keeping the shaft seal device warm is circulated back to the lubricating oil system. A method for keeping the shaft sealing device of a low-temperature blower warm.