JPS6050962B2 - radial turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an expansion turbine used for cold generation in a cryogenic gas separation device, a power turbine for small-capacity energy recovery, and a radial turbine used in a turbine compressor. It is related to.

Conventionally, radial turbines have been used only as expansion turbines with a relatively low heat drop, such as in air separation devices.

However, recently, expansion turbines with a considerably high heat drop and large capacity have come to be used for liquefying hydrogen and helium, for liquefying general gases such as NG, and for power recovery. However, since the conventional radial turbine has one impeller per unit, it is necessary to install multiple units in series for high heat drop turbines, and multiple units in parallel for large capacity turbines. As described above, when the number of installed turbines increases, problems arise such as an increase in equipment costs, an increase in installation space, and an increase in equipment failure rate. In addition, in expansion turbines used in cryogenic gas separation equipment, etc., the brake side is the room temperature part, so as the number of turbines installed increases, the amount of heat that enters increases proportionally, resulting in cooling loss for the entire equipment. This will lead to deterioration. The present invention aims to double the power generated compared to conventional radial turbines without changing the size.

The present invention is characterized in that impellers for a radial turbine are attached to both ends of a rotating main shaft so that the directions of gas flows flowing out from the impellers are opposite to each other, and a dynamic brake is provided between the two impellers. , are characterized by being housed in one casing.

Embodiments of the present invention will be described below with reference to the drawings. Figure 1 shows the structure of a radial turbine in which impellers are provided at both ends of the main shaft and a generator is used as a brake. A second impeller 8 is attached to each end.

A dynamic brake 11 is installed between both impellers 3 and 8 as a brake. The gas flow of the first turbine passes through the first turbine inlet 1 and into the first turbine case 2.
The air enters the air, undergoes adiabatic expansion by the first impeller 3, and flows to the first turbine outlet 4. On the other hand, regarding the second turbine,
The gas passes through the second turbine inlet 6, enters the second turbine case 7, is adiabatically expanded by the second impeller 8, and flows to the second turbine outlet 9. As is clear from FIG. 1, the direction of the gas flow exiting from the radial turpin impeller 3 is to the left in FIG. 1, and the direction of the gas flow exiting from the radial turbine impeller 8 is The direction of the flow is the first
It is pointing to the right in the diagram.

In other words, the impellers are installed so that the directions of gas flows flowing out from both impellers are opposite to each other with respect to the main shaft. As a result, the thrust force generated on the main shaft cancels each other out, and stable operation can be realized. In addition, as shown in Figure 1, both impellers, the main shaft, and the dynamic brake are housed in a single casing, making the entire structure extremely compact and greatly saving installation space. can be reduced to In particular, in expansion turbines used in cryogenic gas separation equipment, cooling loss in the equipment due to heat entering from the brake side is a problem, but in the configuration shown in Figure 1, both ends of the dynamic brake are connected externally. Since the holes are cut off from each other, the negative effects of heat intrusion from the outside can be reduced. If you want to use this turbine with a large capacity, the gas flowing from the process side is branched just before the turbine, and the gas is made to flow in parallel to the first turbine inlet 1 and the second turbine inlet 6. be able to.

As a result, the first and second impellers 3 and 8 can do exactly the same expansion work, so the dynamic brake 1
1 will have the power of two expansion turbines added to it. Next, when it is desired to use this turbine for a high thermal drop, the entire amount of gas flowing from the process side is guided to the first turbine inlet 1, and the first impeller 3 first performs high-pressure expansion work. Furthermore, the gas leaving the first turbine outlet 4 is
By piping it in series to the second turbine inlet 6, the second impeller 8 performs a low-pressure expansion work and the gas flows out to the second turbine outlet 9. As a result, the first and second impellers 3 and 8 perform the expansion work of 12 high-pressure and low-pressure turbines, compared to a conventional radial turbine that incorporates one impeller. . When radial turbines are used under high pressure, the pressure-induced increase in thrust force becomes a problem.

The thrust force has an important relationship with the impeller outer diameter in addition to the operating pressure. FIG. 2 shows an example in which the radial turbine according to the present invention is used for high heat head.
The high-pressure gas having a pressure P1 passes through the high-pressure turbine inlet 12 and is transferred from the high-pressure turbine case 13 to the high-pressure turbine impeller 1.
4, the gas undergoes high-pressure expansion here and flows to the high-pressure turbine outlet 15, becomes low pressure P2, is guided to the low-pressure turbine inlet 16, and enters the low-pressure turbine impeller 18 from the low-pressure turbine case 17. , where it undergoes low pressure expansion and flows to the low pressure turbine outlet 19. In this case, the thrust force acting in the direction of arrow A in the figure is determined by the pressure P1 acting on the back area P1 of the high-pressure turbine pin impeller 14,
The thrust force acting in the direction of arrow B in the figure is determined by the pressure P2 acting on the back area D2 of the low pressure turbine impeller 18. On the other hand, when comparing the actual flow rates flowing through the high-pressure and low-pressure turbines, the low-pressure turbine is larger. Therefore, the impeller of the low pressure turbine is also larger. Therefore, P1>P2,
This means that Dl<D2. Therefore, by adjusting the pressure and the size of the impeller, it is possible to cancel out the thrust force of the turbine, which promotes a reduction in the load on the thrust bearing, leading to improved reliability of the thrust bearing. As described above, according to the present invention, one radial turbine can perform the work of two radial turbines.

As a result, the generated power can be doubled without changing the size of the radial turbine, and a large output can be expected with a small size, so the turbine equipment cost per output can be halved.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of an expansion turbine showing an embodiment of the present invention. 1...First turbine inlet, 2...First
Turbine case, 3... First impeller, 4...
...First turbine outlet, 5...Main shaft, 6...
...Second turbine inlet, 7...Second turbine case, 8...Second impeller, 9...Second turbine outlet, 10...Bearing, 11...Dynamic brake, 12...High pressure turbine inlet, 13...
... High pressure turbine case, 14 ... High pressure turbine impeller, 15 ... High pressure turbine outlet, 16.
...Low pressure turbine inlet, 17 ...Low pressure turbine case, 18 ...Low pressure turbine impeller,
19...Low pressure turbine outlet, 20...
Shaft seal part.

Claims (1)

[Claims] 1 Install radial turbine impellers at both ends of the main shaft so that the directions of gas flows flowing out from the impellers are opposite to each other with respect to the main shaft, and provide a dynamic brake between the two impellers. , and a radial turbine characterized by housing them in one casing.