A thermal system for driving an industrial steam turbine

Abstract

This invention relates to the field of steam turbine technology, and in particular to a thermal system for an industrial driven steam turbine. The system includes a main steam pipeline, a condensate pipeline, a pneumatic vacuum pump, and a drain pipeline. The drain pipeline is equipped with a water jet injector and a drain expansion tank. The drain expansion tank has multiple inlet branches, which are respectively connected to the main steam pipeline and the drain point of the steam turbine. The drain expansion tank has multiple outlet branches, one of which is connected to a sewage ditch, another to the condensate pipe of the condenser, and the third to the condensate pipe of the condenser via the water jet injector. The output end of the pneumatic vacuum pump is connected to the working water inlet of the water jet injector via the condensate pipeline. This system can promptly drain condensate from the pipeline under start-up warm-up conditions and low-load or fault conditions, preventing water ingress into the steam turbine and causing water hammer accidents or other equipment malfunctions, thus improving safety.

Description

Technical Field

[0001] This invention relates to the field of steam turbine technology, and in particular to a thermal system for an industrial driven steam turbine. Background Technology

[0002] Currently, some chemical plants have a certain surplus of low-pressure steam in their steam networks during summer operation. This surplus steam is often not fully utilized, leading to large-scale venting. This not only results in a serious waste of steam and heat energy in the production system, but also prevents the recovery of condensate due to the venting of this steam into the atmosphere, thus increasing the system's demineralized water consumption and the production load of the demineralized water unit. To utilize this surplus steam, a condensing steam turbine can be used to replace the original drive motor, along with a vacuum condensation system to recover the condensate. This achieves the goals of recovering and utilizing steam heat energy, saving electricity consumption in the circulating water system, and returning steam condensate to the process condensate tank. This requires a supporting thermal system, which refers to the combination of all equipment and pipelines that enable the continuous heat-work conversion process of the steam turbine. It generally includes the main steam pipeline and vacuum extraction pipeline. However, condensate can easily remain in the main steam pipeline during unit start-up, warm-up, low-load, or fault conditions. This condensate entering the steam turbine can cause water hammer accidents or other equipment failures. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a thermal system for industrial drive steam turbines that can promptly drain condensate from the pipes during start-up warm-up and under low load or fault conditions, preventing water ingress into the steam turbine and causing water hammer accidents or other equipment failures, thereby improving safety.

[0004] To achieve the above objectives, the thermal system of the industrial turbine driven by the present invention includes a main steam pipeline connected to the main steam valve of the turbine; a condensate pipeline equipped with a condenser, the condenser's condensing pipe connected to the turbine's exhaust valve via a pipeline; a pneumatic vacuum pump connected to the main steam pipeline and the condenser's condensing pipe via a pipeline; and a drain pipeline equipped with a water jet injector and a drain expansion tank. The drain expansion tank has multiple inlet branches connected to the main steam pipeline and the turbine's drain points, respectively. The drain expansion tank has multiple outlet branches, one of which is connected to a sewage ditch, one to the condenser's condensing pipe, and one connected to the condenser's condensing pipe via the water jet injector. The output end of the pneumatic vacuum pump is connected to the water jet injector via the condensate pipeline. The working water inlet is connected; during turbine startup, shutdown, or low-load operation, condensate collected in the main steam pipeline and turbine condensate drain points is collected in the condensate expansion tank through the condensate drain pipe. When there is too much condensate in the condensate expansion tank, it is discharged into the sewage ditch through an output branch pipe. When the input and output of the condensate expansion tank are balanced, it is directly transported to the condenser through an output branch pipe. When it is necessary to quickly discharge the condensate in the main steam pipeline and turbine, the main steam pipeline sends air to the pneumatic vacuum pump, the pneumatic vacuum pump operates, and at the same time, the condensate in the condensate pipeline is quickly sprayed into the water jet injector, and expands in the expansion chamber of the water jet injector to form a negative pressure, which quickly extracts the condensate in the condensate expansion tank and transports it to the condenser. Thus, during startup warm-up and low-load or fault conditions, the condensate in the pipeline can be drained in time, preventing water ingress into the turbine and causing water hammer accidents or other equipment failures, thereby improving safety.

[0005] Preferably, the drainage points include a drainage point before the main steam valve of the steam turbine, a drainage point before the steam seal, a drainage point after the steam seal, a drainage point on the main steam valve stem, a drainage point in the front cylinder of the steam turbine, and a drainage point in the rear cylinder of the steam turbine; the above drainage points can quickly and comprehensively drain the condensate accumulated in the equipment.

[0006] Preferably, it also includes a steam-water separator. A steam-water separator is installed at the steam inlet of the turbine in the main steam pipeline. An electric valve is installed before the steam-water separator, and a manual shut-off valve is installed before the steam inlet of the turbine body. By setting up a steam-water separator, the moisture in the input steam is separated and discharged to avoid damage to the turbine and other equipment. The manual shut-off valve facilitates the hydrostatic test of the steam pipeline before it.

[0007] Preferably, the pneumatic vacuum pumping equipment includes a two-stage jet ejector and a starting ejector. The working steam inlet of the two-stage jet ejector is connected to the main steam pipeline, the mixed steam inlet of the two-stage jet ejector is connected to the condenser's condensing pipe, the exhaust port of the main ejector of the two-stage jet ejector is connected to the condenser, the condensate outlet of the two-stage jet ejector is connected to the condensate pipeline and also to the working water inlet of the water jet injector. The working steam inlet of the starting ejector is connected to the main steam pipeline, the mixed steam inlet of the starting ejector is connected to the condenser's condensing pipe, and the exhaust port of the starting ejector is open to the atmosphere. The two-stage jet ejector and the starting ejector remove air from the condenser, auxiliary equipment, and pipelines during turbine startup to achieve the required vacuum value. During normal operation of the turbine unit, the system removes non-condensable gases accumulated in the condenser to maintain system vacuum.

[0008] Preferably, it also includes a shaft seal subsystem, in which shaft seals are provided on multiple cylinders of the steam turbine, including front steam seals, rear steam seals and diaphragm steam seals. Multiple shaft seals are connected to the main steam pipeline in front of the main steam valve of the steam turbine through pipelines. Steam leaking from the shaft seals is connected to the condenser condenser pipe through pipelines. The shaft seal system reduces the leakage loss at the shaft seals at both ends of the steam turbine cylinders.

[0009] Preferably, all of the multiple steam seals adopt a high-low tooth labyrinth type to further reduce steam leakage losses.

[0010] Preferably, it also includes two condensate pumps. The input ends of the two condensate pumps are connected to the outlet of the condenser tubes of the condenser through pipelines. Electric regulating valves are installed at the outlets of the two condensate pumps. The output ends of the two condensate pumps extend into the condensate tank of the water treatment process. After the steam enters the turbine to do work, the exhaust steam enters the condenser and is cooled into condensate. The condensate is then transported to the condensate tank of the whole plant by the condensate pumps and enters the boiler for reheating to generate high temperature and high pressure steam, realizing the recycling of condensate. The capacity of the two condensate pumps is 1% of the total capacity, one for use and one for standby.

[0011] Preferably, the system also includes a circulating cooling water pipeline. This pipeline includes a ball catcher, a ball pump, a ball launching chamber, a double oil cooler, and a water filter. The ball catcher, ball pump, and ball launching chamber constitute a cooling water circulating pump group. The output end of the pump group is connected to the input end of the condenser's cooling pipeline, and the input end of the pump group is connected to the output end of the condenser's cooling pipeline. The double oil cooler and water filter constitute a cooler group. The input end of the cooler group is connected to the output end of the condenser's cooling pipeline via a pipeline, and the output end of the cooler group is connected to the input end of the condenser's cooling pipeline via a pipeline. The condenser's input and output pipelines are respectively connected to an external circulating water system. The circulating cooling water pipeline continuously cools the condenser and the double oil cooler to ensure the normal operation of the unit and improves the cooling effect on the condenser and the double oil cooler by connecting to the external circulating water system.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: When the turbine unit is running at low load during turbine startup, shutdown, or operation, the condensate collected in the main steam pipeline and the turbine's drain points is collected in the drain expansion tank through the drain pipeline. When there is too much condensate in the drain expansion tank, it is discharged into the sewage ditch through an output branch pipe. When the input and output of the drain expansion tank are balanced, it is directly transported to the condenser through an output branch pipe. When it is necessary to quickly discharge the condensate in the main steam pipeline and the turbine, the main steam pipeline sends air to the pneumatic vacuum pump. The pneumatic vacuum pump operates and can drive the condensate in the condensate pipeline to be quickly sprayed into the water jet injector. The condensate expands in the expansion chamber of the water jet injector to form a negative pressure, which quickly extracts the condensate in the drain expansion tank and transports it to the condenser. Thus, the condensate in the pipeline can be drained in time during startup warm-up and low load or fault conditions, preventing water from entering the turbine and causing water hammer accidents or other equipment failures, thereby improving safety. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of the present invention;

[0014] Figure 2 This is a schematic diagram of the main steam pipeline of the present invention;

[0015] Figure 3 This is a schematic diagram of the drainage pipe structure of the present invention;

[0016] Figure 4 This is a schematic diagram of the structure of the steam seal pipeline of the present invention;

[0017] Figure 5 This is a schematic diagram of the cooling water pipeline of the present invention;

[0018] Figure 6 This is a schematic diagram of the condensate pipeline of the present invention;

[0019] The attached diagram shows the following components: 1. Steam turbine; 2. Gearbox; 3. Condenser; 4. Two-stage ejector; 5. Start-up ejector; 6. Water jet injector; 7. Double oil cooler; 8. Water filter; 9. Drain expansion tank; 10. Condensate pump; 11. Steam-water separator; 12. Ball catcher; 13. Ball pump; 14. Ball launching chamber; 15. Connection to plant steam pipeline; 16. Connection to plant condensate pipeline; 17. Connection to condensate pump. 18. Outlet pipeline; 19. Demineralized water pipeline; 20. Condenser makeup water; 21. Plant circulating water return pipeline; 22. Plant circulating water supply pipeline; 23. Main steam valve; 24. Corrosion-resistant exhaust steam; 25. Sewage discharge; 26. Main steam pipeline; 27. Condensate pipeline; 28. Drainage pipeline; 29. ​​Circulating cooling water pipeline; 30. Steam seal pipeline; 31. Exhaust steam pipeline; 32. Steam-water mixing pipeline. Detailed Implementation

[0020] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0021] Example 1:

[0022] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, a thermal system for an industrial steam turbine includes a main steam pipeline connected to the main steam valve of the turbine; a condensate pipeline equipped with a condenser 3, the condensing pipe of which is connected to the exhaust valve of the turbine via a pipeline; a pneumatic vacuum pump connected to the main steam pipeline and the condensing pipe of the condenser 3 via a pipeline; and a drain pipeline equipped with a water jet injector 6 and a drain expansion tank 9. The drain expansion tank 9 has multiple inlet branches connected to the main steam pipeline and the drain point of the turbine, and multiple outlet branches, one of which is connected to a sewage ditch, one to the condensing pipe of the condenser 3, and one to the condenser 3 via the water jet injector 6. The condensate pipe connection connects the output end of the pneumatic vacuum pump to the working water inlet of the water jet injector 6 via a condensate pipe. The drainage points include: a drainage point before the main steam valve of the turbine, a drainage point for the front steam seal, a drainage point for the rear steam seal, a drainage point for the main steam valve stem, a drainage point for the front cylinder of the turbine, and a drainage point for the rear cylinder of the turbine. It also includes a steam-water separator 11, installed at the turbine inlet on the main steam pipeline. An electric valve is installed before the steam-water separator 11, and a manual shut-off valve is installed before the turbine body inlet. Furthermore, it includes a shaft seal subsystem, with shaft seals installed on multiple cylinders of the turbine, including a front steam seal, a rear steam seal, and a diaphragm steam seal. These shaft seals are connected to the main steam pipeline before the main steam valve of the turbine via pipelines. Steam leaking from the shaft seals is connected to the condenser pipe of the condenser 3 via pipelines. All the multiple steam seals are high-low toothed labyrinth type.

[0023] During turbine startup, shutdown, or low-load operation, condensate collected in the main steam pipeline and turbine condensate drain points flows into the condensate expansion tank 9 via the condensate drain pipe. When there is excessive condensate in the expansion tank 9, it is discharged into the sewage ditch through an output branch pipe. When the input and output of the expansion tank 9 are balanced, it is directly supplied to the condenser 3 through an output branch pipe. When it is necessary to quickly discharge the condensate from the main steam pipeline and turbine, the main steam pipeline supplies air to the pneumatic vacuum pump. The pneumatic vacuum pump operates and drives the condensate in the condensate pipeline to be rapidly sprayed into the water jet injector 6. The condensate expands in the expansion chamber of the water jet injector 6, creating negative pressure to... The condensate in the expansion tank 9 is quickly extracted and transported to the condenser 3, thus ensuring timely drainage of condensate in the pipeline during start-up, warm-up, low-load, or fault conditions. This prevents water from entering the turbine and causing water hammer accidents or other equipment malfunctions, improving safety. The drainage points mentioned above allow for the rapid and comprehensive discharge of condensate accumulated in the equipment. The steam-water separator 11 separates and discharges moisture from the input steam, preventing moisture from damaging the turbine and other equipment. The manual shut-off valve facilitates hydrostatic testing of the upstream steam pipeline. The shaft sealing system reduces air leakage at the shaft seals at both ends of the turbine cylinder, further reducing steam leakage losses.

[0024] Example 2:

[0025] like Figure 3 As shown, the pneumatic vacuum pumping device includes a two-stage jet ejector 4 and a starting ejector 5. The working steam inlet of the two-stage jet ejector 4 is connected to the main steam pipeline, the mixed steam inlet of the two-stage jet ejector 4 is connected to the condenser pipe of the condenser 3, the exhaust port of the main ejector of the two-stage jet ejector 4 is connected to the condenser 3, the condensate outlet of the two-stage jet ejector 4 is connected to the condensate pipeline and also connected to the working water inlet of the water jet injector 6. The working steam inlet of the starting ejector 5 is connected to the main steam pipeline, the mixed steam inlet of the starting ejector 5 is connected to the condenser pipe of the condenser 3, and the exhaust port of the starting ejector 5 is open to the atmosphere.

[0026] The two-stage ejector 4 and the start-up ejector 5 remove air from the condenser 3, auxiliary equipment, and pipelines when the turbine unit starts up, so that the vacuum reaches the required start-up value, i.e., the suction state. During normal operation of the turbine unit, the system removes non-condensable gases accumulated in the condenser 3 to maintain the system vacuum.

[0027] Example 3:

[0028] like Figure 5 and Figure 6As shown, it also includes two condensate pumps 10. The input ends of the two condensate pumps 10 are connected to the outlet of the condenser tube of the condenser 3 via pipelines. Electric regulating valves are installed at the outlets of the two condensate pumps 10, and the output ends of the two condensate pumps 10 extend into the condensate tank of the water treatment process. It also includes a circulating cooling water pipeline, which is equipped with a ball catcher 12, a ball pump 13, a ball launching chamber 14, a double oil cooler 7, and a water filter 8. The ball catcher 12, the ball pump 13, and the ball launching chamber 14 constitute a cooling system. A cooling water circulation pump set is provided, the output end of which is connected to the input end of the cooling pipe of the condenser 3, and the input end of which is connected to the output end of the cooling pipe of the condenser 3. A double oil cooler 7 and a water filter 8 constitute a cooler group, the input end of which is connected to the output end of the cooling pipe of the condenser 3 through a pipe, and the output end of which is connected to the input end of the cooling pipe of the condenser 3 through a pipe. The input and output pipes of the condenser 3 are respectively connected to an external circulating water circuit.

[0029] After steam enters the turbine to do work, the exhaust steam enters the condenser 3 and is cooled into condensate. The condensate is then pumped by the condensate pump 10 to the plant's process condensate tank and then enters the boiler for reheating to generate high-temperature and high-pressure steam. This realizes the recycling of condensate. The two condensate pumps 10 have a capacity of 110%, with one in use and one on standby. The condenser 3 and the double oil cooler 7 are continuously cooled by cooling water through the above-mentioned circulating cooling water pipeline to ensure the normal operation of the unit. The system is also connected to the external circulating water circuit to improve the cooling effect on the condenser 3 and the double oil cooler 7.

[0030] like Figures 1 to 6As shown, in this embodiment, the thermal system of the industrial turbine driven by the turbine operates as follows: First, during turbine startup, shutdown, or low-load operation, condensate collected in the main steam pipeline and the turbine's drain points is gathered into the condensate expansion tank 9 via the drain pipe. Then, when there is excessive condensate in the condensate expansion tank 9, it is discharged into the drainage ditch through an output branch pipe. When the input and output of the condensate expansion tank 9 are balanced, it is directly transported to the condenser 3 through an output branch pipe. Then, when it is necessary to quickly discharge the condensate from the main steam pipeline and the turbine, the main steam pipeline supplies air to the two-stage ejector 4 and the starting ejector 5. The two-stage ejector 4 and the starting ejector 5 then... When the unit starts up, the air in the condenser 3, as well as in the auxiliary equipment and pipelines, is expelled to make its vacuum reach the required starting value. During normal operation of the turbine unit, the system removes the non-condensable gases accumulated in the condenser 3 to maintain the system vacuum. Finally, the two-stage ejector pump 4 and the start-up ejector 5 operate and can drive the condensate in the condensate pipeline to be quickly sprayed into the water jet injector 6. The water jet injector 6 expands in the expansion chamber to form a negative pressure, which quickly extracts the condensate in the condensate expansion tank 9 and delivers it to the condenser 3. In this way, the condensate in the pipeline can be drained in time during start-up warm-up and under low load or fault conditions, preventing water from entering the turbine and causing water hammer accidents or other equipment failures.

[0031] The main functions achieved by this invention are:

[0032] It can promptly drain condensate from the pipes during startup warm-up and under low load or fault conditions, preventing water from entering the turbine and causing water hammer accidents or other equipment failures, thus improving safety;

[0033] The circulating cooling water pipeline continuously cools the condenser 3 and the double oil cooler 7 with cooling water to ensure the normal operation of the unit, and is connected to the external circulating water circuit to improve the cooling effect on the condenser 3 and the double oil cooler 7.

[0034] The steam condensate can be recycled and transported to the plant's process condensate tank via condensate pump 10, and then reheated in the boiler to generate high-temperature and high-pressure steam, thus realizing the recycling of condensate.

[0035] The installation, connection, or setup methods of the thermal system for the industrial driven steam turbine described in this invention are all common mechanical methods, and any method that can achieve its beneficial effects can be implemented. The steam turbine 1, steam-water separator 11, gearbox 2, condenser 3, two-stage ejector 4, start-up ejector 5, water jet injector 6, double oil cooler 7, water filter 8, condensate expansion tank 9, condensate pump 10, ball catcher 12, ball pump 13, and ball launching chamber 14 of the thermal system for the industrial driven steam turbine are commercially available. Technical personnel in this industry only need to install and operate them according to the accompanying instruction manual, without requiring any creative work from those skilled in the art.

[0036] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A thermal system for an industrial steam turbine, comprising a main steam pipeline connected to the main steam valve of the steam turbine; a condensate pipeline equipped with a condenser (3), the condensing pipe of the condenser (3) being connected to the exhaust valve of the steam turbine via a pipeline; and a pneumatic vacuum pumping device connected to the main steam pipeline and the condensing pipe of the condenser (3) via a pipeline; characterized in that, It also includes a drainage pipeline, which is equipped with a water jet injector (6) and a drainage expansion tank (9). The drainage expansion tank (9) is equipped with multiple water inlet branches, which are respectively connected to the main steam pipeline and the drainage point of the steam turbine. The drainage expansion tank (9) is equipped with multiple output branches, one of which is connected to the sewage ditch, one of which is connected to the steam condenser pipe of the condenser (3), and one of which is connected to the steam condenser pipe of the condenser (3) through the water jet injector (6). The output end of the pneumatic vacuum pump is connected to the working water inlet end of the water jet injector (6) through the condensate pipeline. The pneumatic vacuum pump includes two stages of injection. The two-stage jet ejector (4) and the start-up ejector (5) are connected. The working steam inlet of the two-stage jet ejector (4) is connected to the main steam pipeline. The mixed steam inlet of the two-stage jet ejector (4) is connected to the condenser pipe of the condenser (3). The exhaust port of the main ejector of the two-stage jet ejector (4) is connected to the condenser (3). The condensate outlet of the two-stage jet ejector (4) is connected to the condensate pipeline and to the working water inlet of the water jet injector (6). The working steam inlet of the start-up ejector (5) is connected to the main steam pipeline. The mixed steam inlet of the start-up ejector (5) is connected to the condenser pipe of the condenser (3). The exhaust port of the start-up ejector (5) is connected to the atmosphere. It also includes a circulating cooling water pipeline, which is equipped with a ball catcher (12), a ball pump (13), a ball launching chamber (14), a double oil cooler (7), and a water filter (8). The ball catcher (12), the ball pump (13), and the ball launching chamber (14) constitute a cooling water circulating pump group. The output end of the pump group is connected to the input end of the cooling pipeline of the condenser (3). The input end of the pump group is connected to the output end of the cooling pipeline of the condenser (3). The double oil cooler (7) and the water filter (8) constitute a cooler group. The input end of the cooler group is connected to the output end of the cooling pipeline of the condenser (3) through a pipeline. The output end of the cooler group is connected to the input end of the cooling pipeline of the condenser (3) through a pipeline. The input pipeline and the output pipeline of the condenser (3) are respectively connected to the external circulating water pipeline.

2. The thermal system for the industrial drive steam turbine as described in claim 1, characterized in that, The drainage points are: the drainage point before the main steam valve of the steam turbine, the drainage point of the front steam seal, the drainage point of the rear steam seal, the drainage point of the main steam valve stem, the drainage point of the front cylinder of the steam turbine, and the drainage point of the rear cylinder of the steam turbine.

3. The thermal system for the industrial drive steam turbine as described in claim 1, characterized in that, It also includes a steam-water separator (11), with a steam-water separator (11) installed at the steam inlet of the turbine in the main steam pipeline, an electric valve installed in front of the steam-water separator (11), and a manual shut-off valve installed in front of the steam inlet of the turbine body.

4. The thermal system for an industrial drive steam turbine as described in claim 1, characterized in that, It also includes a shaft seal subsystem. Multiple cylinders of the steam turbine are equipped with shaft seals, including front steam seal, rear steam seal and diaphragm steam seal. Multiple shaft seals are connected to the main steam pipeline in front of the main steam valve of the steam turbine through pipelines. The steam leaking from the shaft seals is connected to the condenser pipe of the condenser (3) through pipelines.

5. The thermal system for an industrial drive steam turbine as described in claim 1, characterized in that, It also includes two condensate pumps (10), the input ends of the two condensate pumps (10) are connected to the outlet end of the steam condenser pipe of the condenser (3) through pipelines, the outlets of the two condensate pumps (10) are equipped with electric regulating valves, and the output ends of the two condensate pumps (10) extend into the condensate tank of the water treatment process.

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