CN210486558U - Vacuum system suitable for gas-steam combined cycle unit - Google Patents
Vacuum system suitable for gas-steam combined cycle unit Download PDFInfo
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- CN210486558U CN210486558U CN201921437012.5U CN201921437012U CN210486558U CN 210486558 U CN210486558 U CN 210486558U CN 201921437012 U CN201921437012 U CN 201921437012U CN 210486558 U CN210486558 U CN 210486558U
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Abstract
The utility model discloses a vacuum system suitable for a gas-steam combined cycle unit, which comprises a steam ejector, a condenser and a vacuum pump which are connected in sequence; the steam ejector comprises a head cavity, an inlet cone part, a throat mixing nozzle and a diffuser which are sequentially connected, wherein a power nozzle is arranged in the head cavity, the front end of the power nozzle is a jet orifice and faces the inlet cone part, the side wall of the head cavity is also communicated with an introducing port, the inlet cone part and the diffuser are both in cone shapes, and small cone-shaped port ends are respectively connected to two ends of the throat mixing nozzle; the rear end of the power nozzle is connected with a steam pipeline, the introducing port is connected with an air exhaust main pipe, the diffuser is connected with a steam side inlet on the condenser, a steam side outlet on the condenser is connected with a vacuum pump, and the condenser is further connected with an exhaust device. The utility model discloses ensure unit safe operation, need improve the condenser vacuum and reach the design requirement.
Description
Technical Field
The present invention relates to combined cycle unit equipment, and more particularly to a vacuum system suitable for use in a gas-steam combined cycle unit.
Background
The gas-steam combined cycle unit is a power device integrating steam turbine cycle and steam turbine cycle, i.e. combined cycle using gas as high-temperature working medium, steam as low-temperature working medium and using the exhaust of gas turbine as heating source of steam turbine device cycle.
The coal clean combustion technology is a research field which is paid great attention to by all developed industrial countries at present, and the coal-fired gas-steam combined cycle is a power generation technology with the greatest development prospect because the thermal efficiency of a thermal power plant can be greatly improved and the pollution problem is solved. The general engineering construction scale is two sets of 'two-in-one' gas-steam combined cycle units, the two sets of units are arranged in a mirror image mode, and each set of unit comprises 2 gas turbine generator sets, 2 waste heat boilers and 1 steam turbine generator set. When the unit is in a winter heat supply working condition, the low-pressure cylinder of the steam turbine is split, the high-intermediate pressure cylinder operates in a backpressure mode, and exhaust steam and low-pressure main steam of the unit are all used for heating a net heater; when the heat load is low in the initial stage and the final stage of heat supply, the unit operates in a condensation pumping mode; when the heat supply is not performed, the high-medium pressure cylinder and the low-pressure cylinder are connected into a shaft through the SSS clutch, and the unit operates in a pure condensation mode. The condenser vacuumizing system is one of important systems of a unit, and air in a steam side space of the condenser, an auxiliary pipeline and equipment is pumped out through a vacuum pump at the initial starting stage of the unit so as to meet the starting requirement of the steam turbine; and in the normal operation of the unit, non-condensed gas accumulated in an air area of the condenser is removed, and the back pressure of the steam turbine is maintained. Because the steam turbine has multiple operation modes such as pure condensation, extraction condensation, backpressure and the like, and the heating season mainly operates in the backpressure mode, the gas-steam combined cycle power generation and heat supply unit has huge energy-saving potential in the aspects of optimized design and economic operation of a vacuum system.
However, after the unit runs for a long time, the reason that the vacuum of the condenser deviates from the design value greatly when the heat supply amount is low in summer working conditions, even the vacuum is close to the trip value once, the reason that the vacuum of the summer working conditions is not up to the standard is caused by the reasons that the circulating water temperature is high in summer working conditions, the efficiency of the vacuum pump is poor, and the steam extraction amount of the steam turbine is small is found. Meanwhile, the steam corrosion at two ends of an impeller of a condenser vacuum pump is serious, and the exceeding of the temperature of sealing water of the vacuum pump is a main reason for causing the steam corrosion of the impeller, so that the vacuum degree of the condenser is required to be improved to meet the design requirement for improving the economical efficiency and ensuring the safe operation of a unit.
SUMMERY OF THE UTILITY MODEL
To the above-mentioned defect that exists among the prior art, the utility model aims at providing a vacuum system suitable for on gas-steam combined cycle unit ensures the unit safe operation, needs to improve the condenser vacuum and reaches the designing requirement.
In order to achieve the above purpose, the utility model adopts the following technical scheme:
a vacuum system suitable for a gas-steam combined cycle unit comprises a steam ejector, a condenser and a vacuum pump which are sequentially connected;
the steam ejector comprises a head cavity, an inlet cone part, a throat mixing nozzle and a diffuser which are sequentially connected, wherein a power nozzle is arranged in the head cavity, the front end of the power nozzle is a jet orifice and faces the inlet cone part, the side wall of the head cavity is also communicated with an introducing port, the inlet cone part and the diffuser are both in cone shapes, and small cone-shaped port ends are respectively connected to two ends of the throat mixing nozzle;
the rear end of the power nozzle is connected with a steam pipeline, the introducing port is connected with an air exhaust main pipe, the diffuser is connected with a steam side inlet on the condenser, a steam side outlet on the condenser is connected with a vacuum pump, and the condenser is further connected with an exhaust device (a hot well).
The head chamber is connected with the inlet cone portion through a transition section with a gradually reduced diameter.
The diameter of the large opening end of the inlet cone part is 1.1-1.3 times of that of the small opening end.
The length of the inlet cone part is 3.0-4.0 times of the diameter of the small opening end.
The vacuum pump is provided with two sets.
And an isolating valve and an adjusting valve are arranged between the steam ejector and the steam pipeline and between the steam ejector and the air extraction main pipe.
And a regulating valve is arranged between the condenser and the vacuum pump.
In the technical scheme, the utility model provides a vacuum system suitable for on gas-steam combined cycle unit has improved the vaporization temperature that vacuum pump inlet pressure corresponds and is higher than the working solution actual temperature, avoids producing the cavitation, guarantees that the vacuum of condenser is not influenced by vacuum pump performance, is in high vacuum state all the time, can provide the condenser vacuum, and performance is stable simultaneously, and safe and reliable is very energy-conserving and use cost is low.
Drawings
FIG. 1 is a schematic diagram of a frame of a vacuum system of the present invention;
fig. 2 is a cross-sectional view of the steam ejector of fig. 1.
Detailed Description
The technical solution of the present invention will be further explained with reference to the accompanying drawings and examples.
Referring to fig. 1 to 2, the vacuum system for a gas-steam combined cycle unit provided by the present invention includes a steam ejector 1, a condenser 2 and a vacuum pump 3 connected in sequence.
Preferably, the steam ejector 1 comprises a head chamber 4, an inlet cone portion 5, a throat mixing nozzle 6 and a diffuser 7 which are connected in sequence, wherein a power nozzle 8 is installed in the head chamber 4, the power nozzle 8 is horizontally arranged, the front end of the power nozzle is a jet opening 9 facing the inlet cone portion 5, an inlet 10 is further communicated with the side wall of the head chamber 4, the inlet cone portion 5 and the diffuser 7 are both cone-shaped, and the cone-shaped small-opening ends are respectively connected to two ends of the throat mixing nozzle 6.
Preferably, the rear end of the power nozzle 9 is connected to a steam line 11, the auxiliary steam is used as a high-pressure power medium, the inlet 10 is connected to an extraction main pipe 12, the high-pressure steam is injected through the power nozzle 9, and the low-pressure steam is sucked into the head chamber 4 from the inlet 10. The diffuser 7 is connected with a steam side inlet on the condenser 2, a steam side outlet on the condenser 2 is connected with the vacuum pump 3, and the condenser 2 is also connected with a steam exhaust device (hot well) 14.
Preferably, the head chamber 4 is connected to the inlet cone portion 5 by a transition section 15 of decreasing diameter in order to promote the suction of low pressure steam towards the inlet cone portion 5.
Preferably, the diameter D1 of the large opening end of the inlet cone portion 5 is 1.1 to 1.3 times the diameter D2 of the small opening end, so as to increase the discharge pressure of the diffuser 7.
Preferably, the length L of the inlet cone portion 5 is 3.0 to 4.0 times the diameter D2 of the small end, which also increases the discharge pressure of the diffuser 7.
Preferably, two vacuum pumps 3 are arranged, when the unit is started, the two vacuum pumps 3 run simultaneously to establish vacuum, the steam ejector 1 is stopped, the vacuum degree reaches a set value, after the vacuum establishment is initially completed, the steam ejector 1 runs, and the two vacuum pumps 3 are stopped and kept in vacuum.
Preferably, an isolation valve and an adjusting valve are arranged between the steam ejector 1 and the steam pipeline 11 and between the steam ejector and the extraction main pipe 12.
Preferably, a regulating valve is arranged between the condenser 2 and the vacuum pump 3.
The utility model discloses vacuum system regards as power steam with the auxiliary steam, through steam ejector 1 with the supersonic speed efflux, produces the vacuum, pumps mist, mist gets into condenser 2, and steam is condensed into water, returns the hot-well, and remaining noncondensable gas and noncondensable gas are taken away by vacuum pump 3. The steam side outlet of the condenser 2 is designed to be 10-13 kPa (greater than the maximum inlet pressure of the vacuum pump 3 under summer working conditions), and under the pressure, the vaporization temperature of the working fluid in the vacuum pump 3 is about 45.83-51.06 ℃, which is higher than the temperature of the steam-gas mixture of the condenser 2 by more than 6.5 ℃, so that the vacuum pump 3 is prevented from cavitation.
It will be appreciated by those skilled in the art that the above embodiments are only for illustrating the present invention and are not to be used as limitations of the present invention, and that changes and modifications to the above described embodiments will fall within the scope of the claims of the present invention as long as they are within the spirit and scope of the present invention.
Claims (7)
1. A vacuum system suitable for gas-steam combined cycle unit, its characterized in that: the steam generator comprises a steam ejector, a condenser and a vacuum pump which are connected in sequence;
the steam ejector comprises a head cavity, an inlet cone part, a throat mixing nozzle and a diffuser which are sequentially connected, wherein a power nozzle is arranged in the head cavity, the front end of the power nozzle is a jet orifice and faces the inlet cone part, the side wall of the head cavity is also communicated with an introducing port, the inlet cone part and the diffuser are both in cone shapes, and small cone-shaped port ends are respectively connected to two ends of the throat mixing nozzle;
the rear end of the power nozzle is connected with a steam pipeline, the introducing port is connected with an air exhaust main pipe, the diffuser is connected with a steam side inlet on the condenser, a steam side outlet on the condenser is connected with a vacuum pump, and the condenser is further connected with an exhaust device.
2. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 1, wherein: the head chamber is connected with the inlet cone portion through a transition section with a gradually reduced diameter.
3. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 2, wherein: the diameter of the large opening end of the inlet cone part is 1.1-1.3 times of that of the small opening end.
4. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 3, wherein: the length of the inlet cone part is 3.0-4.0 times of the diameter of the small opening end.
5. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 1, wherein: the vacuum pump is provided with two sets.
6. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 1, wherein: and an isolating valve and an adjusting valve are arranged between the steam ejector and the steam pipeline and between the steam ejector and the air extraction main pipe.
7. A vacuum system adapted for use in a gas-steam combined cycle plant as defined in claim 1, wherein: and a regulating valve is arranged between the condenser and the vacuum pump.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921437012.5U CN210486558U (en) | 2019-08-30 | 2019-08-30 | Vacuum system suitable for gas-steam combined cycle unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921437012.5U CN210486558U (en) | 2019-08-30 | 2019-08-30 | Vacuum system suitable for gas-steam combined cycle unit |
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| Publication Number | Publication Date |
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| CN210486558U true CN210486558U (en) | 2020-05-08 |
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| CN201921437012.5U Active CN210486558U (en) | 2019-08-30 | 2019-08-30 | Vacuum system suitable for gas-steam combined cycle unit |
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2019
- 2019-08-30 CN CN201921437012.5U patent/CN210486558U/en active Active
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