CN212158203U - Vacuum pumping system suitable for ultra-low load operation of air cooling unit - Google Patents
Vacuum pumping system suitable for ultra-low load operation of air cooling unit Download PDFInfo
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- CN212158203U CN212158203U CN201922256151.4U CN201922256151U CN212158203U CN 212158203 U CN212158203 U CN 212158203U CN 201922256151 U CN201922256151 U CN 201922256151U CN 212158203 U CN212158203 U CN 212158203U
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Abstract
A vacuum pumping system suitable for ultra-low load operation of an air cooling unit comprises a vacuum pumping device, a vacuum pumping pipeline, a vacuum pumping interface and an ultra-low pressure vacuum pumping device; the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the air cooling unit through a vacuumizing pipeline, and the outlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing device; the vacuumizing system simultaneously meets the requirements of the air-cooled steam turbine unit on high-load and ultra-low-load operation safety and performance; meanwhile, the back pressure operation of the steam turbine is reduced, the efficiency of the low-pressure cylinder can be improved, and the power of the low-pressure cylinder is increased, so that the operation economy of the unit is improved; the technical transformation has the advantages of small change amount, small risk, small investment and obvious effect.
Description
Technical Field
The utility model belongs to the power plant energy-saving equipment field, concretely relates to evacuation system suitable for air cooling unit ultralow load operation.
Background
More and more thermal power generating units are transformed flexibly at present to improve the peak regulation capacity of the thermal power generating units and consume more electric quantity of renewable energy sources such as wind power and solar energy.
Because the capacity of the generator assembling machine in the new energy fields of wind power, solar energy and the like is continuously increased, the wind power and the solar energy have the characteristic of intermittence. When the power supply of wind power and solar energy rises, the thermal power generating unit needs to reduce the load operation so as to give way to the wind power and the solar energy to ensure that the wind and the light are not abandoned. This is the fundamental purpose of flexibility modification of the thermal power generating unit.
The low load (for example, 50% electric load operation) or ultra-low load operation (for example, 30% electric load operation) of the thermal power generating unit is a normal state of the power generation industry in a period in the future.
In order to adapt to the low-load or ultra-low-load operation of the thermal power turbine unit, necessary transformation and adjustment are needed to be carried out on a system of the existing thermal power unit according to local conditions so as to adapt to the low-load or ultra-low-load operation environment, ensure the safety of the unit and properly improve the operation economy of the unit.
When the steam turbine set is in low load (for example, 50% electric load operation) or ultra-low load operation (for example, 30% electric load operation), the steam inlet flow of the low-pressure cylinder is smaller than the rated working condition. For example, in a subcritical 300MW unit, the rated steam inlet quantity of the low-pressure cylinder under the THA working condition is about 750t/h, and the steam inlet quantity of the low-pressure cylinder is about 300t/h when 50% of electric load operates.
When the steam turbine unit operates under a rated working condition and a high load, the rated steam inlet quantity of the low-pressure cylinder is large, and the blocking back pressure of the direct air cooling unit is usually about 7kpa. In winter, the direct air cooling unit is usually operated at 10kpa.a in the initial and final cold periods and is operated at 13kpa.a or higher in the severe cold period. The limit backpressure of the inlet of the existing vacuum pumping system is generally 4kPa.a, and the requirement of high-load operation can be met.
When the steam turbine unit operates under a rated working condition and a high load, the rated steam inlet quantity of the low-pressure cylinder is large, and the blocking back pressure of the indirect air cooling unit is usually about 5kpa. In winter, the direct air cooling unit is usually operated at 8kpa.a in the initial and final cold periods and is operated at 11kpa.a or higher in the severe cold period. The inlet limit back pressure of the existing vacuum pumping system is generally 3kPa.a, and the requirement of high-load operation can be met.
When the steam turbine set operates at low load or ultra-low load, the operation mode can adopt:
1. and maintaining the past (such as 10KPa.a) operation back pressure operation.
At the moment, along with the further reduction of the steam inlet flow of the low-pressure cylinder, the blast states of the last-stage blade and the second-stage blade are further intensified, so that the outlet temperature of the two-stage blades is greatly increased, the dynamic stress is increased, and the safe operation of the last-stage blade and the second-stage blade is directly influenced. And the measure of spraying water to the low-pressure cylinder to reduce the temperature is adopted, so that the aim of reducing the temperature of the low-pressure outer cylinder can be achieved, and the safety problem of the through-flow part cannot be effectively solved.
2. The operation with reduced back pressure.
According to the characteristics of the steam turbine, when the load rate is low, the blocking back pressure is synchronously reduced. When the steam inlet mass flow of the low-pressure cylinder is reduced and the allowable back pressure of the low-pressure cylinder of the steam turbine is reduced in a proportional manner, the steam exhaust volume flow of the low-pressure cylinder can be maintained to be basically consistent with the minimum cooling volume flow of the low-pressure cylinder under the design condition, the dynamic stress level of the last-stage blade of the low-pressure cylinder is approximately equal to that under the design condition, and the safety and reliability of the integral operation of the low-pressure cylinder are guaranteed at the moment.
Therefore, the method for reducing the operating backpressure of the steam turbine is an effective way for realizing safe and reliable operation under the conditions of low load and small mass flow.
According to the characteristics of the steam turbine, the blocking back pressure value can be 2-4 kPa.a at low load. The running back pressure of the unit at the moment is about 3-6 kpa. At the moment, the limit back pressure of the inlet of the existing vacuumizing device is 3-4 kPa. Therefore, the existing vacuum-pumping system needs to be modified, and the inlet limit backpressure of the vacuum-pumping system is reduced to be less than or equal to 1-1.3 KPa.a.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a vacuum pumping system suitable for air cooling unit ultralow load operation. And simultaneously, the requirements on the high-load and ultra-low-load operation safety and performance of the air-cooled steam turbine unit are met.
In order to realize the purpose, the technical scheme of the utility model is that:
a vacuum pumping system suitable for ultra-low load operation of an air cooling unit comprises a vacuum pumping device, a vacuum pumping pipeline, a vacuum pumping interface and an ultra-low pressure vacuum pumping device; the method is characterized in that: the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the air cooling unit through a vacuumizing pipeline, and the outlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing device.
Further, the air cooling unit adopts direct air cooling and comprises an air cooling island; the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the air cooling island through a vacuumizing pipeline.
Further, the air cooling unit adopts indirect air cooling and comprises an air cooling tower and a condenser; the air cooling tower is connected with the condenser, and the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the condenser through a vacuumizing pipeline.
Furthermore, the ultra-low pressure vacuumizing device is provided with a first bypass pipeline, and the vacuumizing device is provided with a second bypass pipeline.
Furthermore, valves are arranged on the ultra-low pressure vacuum pumping device, an inlet and outlet pipeline of the vacuum pumping device and a bypass pipeline, so that the switching of the operation of the ultra-low pressure vacuum pumping device and the operation of the vacuum pumping device can be realized.
Further, the ultra-low pressure vacuum pumping device is a steam jet air extractor.
Further, the vacuum pumping device comprises a vacuum pump, a steam jet ejector or a Roots blower.
Furthermore, a valve is arranged on the vacuum pumping pipeline.
By the technical scheme, the requirements on the high-load and ultra-low-load operation safety and performance of the air-cooled steam turbine unit are met simultaneously. The efficiency of the low-pressure cylinder can be improved, and the power of the low-pressure cylinder is increased, so that the running economy of the unit is improved.
Drawings
FIG. 1 is a schematic view of an evacuation system suitable for ultra low load operation of a direct air cooling unit;
FIG. 2 is a schematic view of an evacuation system suitable for ultra-low load operation of an indirect air cooling unit;
wherein, 1 air cooling island, 2 indirect air cooling unit condensers, 3 evacuating device, 4 evacuating pipeline, 5 evacuating interface, 6 ultra-low pressure evacuating device, 7 bypass pipeline I, 8 bypass pipeline II, 9 valves.
Detailed Description
The present invention will be further described with reference to the accompanying drawings, and it is to be understood that the description herein is only for purposes of illustration and explanation and is not intended to limit the invention.
Example 1:
a300 MW direct air cooling unit of a certain power plant is put into operation, and a vacuum pumping system comprises: the device comprises an air cooling island, a vacuumizing device, a vacuumizing pipeline, a vacuumizing interface, an ultra-low pressure vacuumizing device, a bypass pipeline I, a bypass pipeline II and a valve.
The inlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing interface of the air cooling island through a vacuumizing pipeline, and the outlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing device.
The ultra-low pressure vacuum pumping device is provided with a first bypass pipeline. The vacuumizing device is provided with a second bypass pipeline. The valves are arranged on the ultra-low pressure vacuum pumping device, the inlet and outlet pipelines of the vacuum pumping device and the bypass pipeline, so that the switching of the operation of the ultra-low pressure vacuum pumping device and the vacuum pumping device can be realized.
The ultra-low pressure vacuum pumping device is a steam jet air extractor, and the inlet limit back pressure is not more than 1-1.3 KPa. The capacity of pumping dry air and wet air can meet the requirement. The parameters of the power steam of the steam jet air extractor and the cooling water of the cooler meet the requirements.
The vacuum pumping device comprises a vacuum pump, a steam jet air extractor or a Roots blower.
The flow cross-sectional area (pipe diameter) of the vacuum line connected to the air cooling island is improved and increased. The vacuum pumping pipeline is provided with pipe fittings such as a valve and the like.
The vacuum-pumping system of low load or ultra-low load operation, its mode of operation is as follows:
(a) when the steam turbine set is in high load, the steam turbine operates according to the original design back pressure, the ultra-low pressure vacuumizing device stops operating, the first bypass pipeline is opened, the second bypass pipeline is closed, and the vacuumizing device operates independently;
(b) when the steam turbine set operates at low load or ultra-low load, the steam turbine operates according to ultra-low back pressure, and the ultra-low pressure vacuumizing device can operate independently or can be connected with the vacuumizing device in series. Closing the first bypass pipeline, opening the second bypass pipeline, stopping the vacuum-pumping device, and independently operating the ultra-low pressure vacuum-pumping device; and closing the first bypass pipeline and the second bypass pipeline, and connecting the vacuumizing device and the ultra-low pressure vacuumizing device in series for operation.
Example 2:
a600 MW indirect air cooling unit of a power plant is put into operation, and a vacuumizing system comprises an air cooling tower, a condenser, a vacuumizing device, a vacuumizing pipeline and a vacuumizing interface valve.
The vacuum pumping system comprises: the device comprises an air cooling tower, a condenser, a vacuumizing device, a vacuumizing pipeline, a vacuumizing interface, an ultra-low pressure vacuumizing device, a bypass pipeline I, a bypass pipeline II and a valve. The air cooling tower is connected with the condenser.
The inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the condenser through a vacuumizing pipeline, and the outlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing device.
The ultra-low pressure vacuum pumping device is provided with a first bypass pipeline. The vacuumizing device is provided with a second bypass pipeline. The valves are arranged on the ultra-low pressure vacuum pumping device, the inlet and outlet pipelines of the vacuum pumping device and the bypass pipeline, so that the switching of the operation of the ultra-low pressure vacuum pumping device and the vacuum pumping device can be realized.
The ultra-low pressure vacuum pumping device is a steam jet air extractor, and the inlet limit back pressure is not more than 1-1.3 KPa. The capacity of pumping dry air and wet air can meet the requirement. The parameters of the power steam of the steam jet air extractor and the cooling water of the cooler meet the requirements.
The vacuum pumping device comprises a vacuum pump, a steam jet air extractor or a Roots blower.
The flow cross-sectional area (pipe diameter) of the vacuum line connected to the air cooling island is improved and increased. The vacuum pumping pipeline is provided with pipe fittings such as a valve and the like.
The vacuum-pumping system of low load or ultra-low load operation, its mode of operation is as follows:
(a) when the steam turbine set is in high load, the steam turbine operates according to the original design back pressure, the ultra-low pressure vacuumizing device stops operating, the first bypass pipeline is opened, the second bypass pipeline is closed, and the vacuumizing device operates independently;
(b) when the steam turbine set operates at low load or ultra-low load, the steam turbine operates according to ultra-low back pressure, and the ultra-low pressure vacuumizing device can operate independently or can be connected with the vacuumizing device in series. Closing the first bypass pipeline, opening the second bypass pipeline, stopping the vacuum-pumping device, and independently operating the ultra-low pressure vacuum-pumping device; and closing the first bypass pipeline and the second bypass pipeline, and connecting the vacuumizing device and the ultra-low pressure vacuumizing device in series for operation.
Finally, it should be noted that: the above description is only for the purpose of explanation and not intended to limit the present invention, and although the present invention has been described in detail, it will be apparent to those skilled in the art that the foregoing descriptions can be modified, or equivalents may be substituted for some of the technical features thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. A vacuum pumping system suitable for ultra-low load operation of an air cooling unit comprises a vacuum pumping device, a vacuum pumping pipeline, a vacuum pumping interface and an ultra-low pressure vacuum pumping device; the method is characterized in that: the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the air cooling unit through a vacuumizing pipeline, and the outlet end of the ultra-low pressure vacuumizing device is connected with the vacuumizing device.
2. The vacuum-pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 1, wherein the air cooling unit adopts direct air cooling and comprises an air cooling island; the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the air cooling island through a vacuumizing pipeline.
3. The vacuum-pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 1, wherein the air cooling unit adopts indirect air cooling and comprises an air cooling tower and a condenser; the air cooling tower is connected with the condenser, and the inlet end of the ultra-low pressure vacuumizing device is connected with a vacuumizing interface of the condenser through a vacuumizing pipeline.
4. The vacuum-pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 2 or 3, wherein the ultra-low pressure vacuum-pumping device is provided with a first bypass pipeline, and the vacuum-pumping device is provided with a second bypass pipeline.
5. The vacuum-pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 4, wherein valves are respectively arranged on the ultra-low pressure vacuum-pumping device, the inlet and outlet pipelines of the vacuum-pumping device and the bypass pipeline, so as to realize switching of the operation of the ultra-low pressure vacuum-pumping device and the vacuum-pumping device.
6. The vacuum pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 1, wherein the ultra-low pressure vacuum pumping device is a steam ejector.
7. The evacuation system suitable for ultra-low load operation of an air cooling unit as claimed in claim 1, wherein the evacuation device comprises a vacuum pump, a steam ejector or a roots blower.
8. The vacuum-pumping system suitable for the ultra-low load operation of the air cooling unit as claimed in claim 1, wherein the vacuum-pumping pipeline is provided with a valve.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922256151.4U CN212158203U (en) | 2019-12-16 | 2019-12-16 | Vacuum pumping system suitable for ultra-low load operation of air cooling unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201922256151.4U CN212158203U (en) | 2019-12-16 | 2019-12-16 | Vacuum pumping system suitable for ultra-low load operation of air cooling unit |
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| CN212158203U true CN212158203U (en) | 2020-12-15 |
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| CN201922256151.4U Active CN212158203U (en) | 2019-12-16 | 2019-12-16 | Vacuum pumping system suitable for ultra-low load operation of air cooling unit |
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