Geothermal power station steam turbine on-line cleaning system

Abstract

The utility model relates to the technical field of turbine cleaning equipment, in particular to a geothermal power station turbine online cleaning system which comprises a condensation water system connected with one end of an inlet pipeline, the other end of the inlet pipeline is connected with a cleaning water pump, and the cleaning water pump is connected with one end of a first outlet pipeline. The other end of the first outlet pipeline is connected with one end of the second outlet pipeline and one end of the recirculation pipeline. The second outlet pipeline is provided with a flowmeter and a needle-shaped regulating valve, the other end of the second outlet pipeline is connected with a plurality of cleaning branches, the tail ends of the cleaning branches are provided with nozzles, the nozzles are connected into a main steam pipeline, and the main steam pipeline is connected with a geothermal power station steam turbine; the other end of the recirculation pipeline is connected with a condensation water system. Condensed water is pressurized through the cleaning water pump and injected into the main steam pipeline after being atomized through the nozzle, steam is used for carrying liquid drops to conduct online washing on the nozzle and blades of the steam turbine, and deposited scale can be effectively removed in the non-stop state.

Description

Technical Field

[0001] This utility model relates to the technical field of steam turbine cleaning equipment, specifically to an online cleaning system for steam turbines in geothermal power plants. Background Technology

[0002] Steam turbines, as rotary steam power plants, are core equipment for converting thermal energy into mechanical energy. They inject high-pressure steam through nozzles onto blades, driving the rotor shaft to rotate and achieve power output. In the field of geothermal power generation, geothermal power plant steam turbines play a crucial role in converting the thermal energy of geothermal fluids into electrical energy. Hot steam has a complex composition, containing large amounts of Ca, Mg, Fe, SiO2, Na, K, and non-condensable gases such as H2S. These substances tend to accumulate on the nozzles and blades during long-term operation of geothermal power plant steam turbines, forming scale. This scale not only reduces the output power and efficiency of the geothermal power plant steam turbine but also corrodes the nozzles and blades, and may even cause abnormal vibrations in the unit, seriously threatening the safe and stable operation of the unit. Field experience has shown that when the blockage rate at the first-stage nozzles of a geothermal power plant steam turbine gradually increases to about 10%-15%, it affects the efficiency and safe operation of the turbine.

[0003] Currently, geothermal turbine cleaning mainly relies on shutdown operations, including three types of techniques: mechanical scraping, chemical soaking, and high-pressure water jetting. Mechanical cleaning requires disassembling the cylinder, which carries the risk of damaging precision blades; while chemical cleaning can dissolve some scale, strong acids and alkalis can accelerate metal corrosion, and the dissolution efficiency of high-concentration silicates in geothermal steam is less than 60%, with residual chemical agents potentially contaminating the geothermal reinjection system; high-pressure water jetting technology, however, can easily lead to coating peeling due to improper impact force control, and still requires shutdown for implementation.

[0004] Existing methods for cleaning geothermal power plant turbines rely on shutdown cleaning, leading to a surge in power generation losses and operation and maintenance costs. An estimated 48-hour shutdown could result in a loss of millions of units of electricity. Furthermore, offline cleaning cannot remove dynamic scale buildup in real time, leaving the unit in a state of prolonged efficiency decline. Even more seriously, the presence of H2S and Fe in geothermal steam... 2+ Ferrous sulfide scale formed at high temperatures is electrochemically active, and conventional chemical cleaning may exacerbate the corrosion process. Although online water washing technology has been explored in the gas turbine field, a mature online cleaning solution has not yet been developed for geothermal turbines due to differences in medium characteristics. Utility Model Content

[0005] To address the technical problem of scale buildup on nozzles and blades of geothermal power plant steam turbines caused by mineral impurities carried by geothermal steam, and the significant losses associated with traditional shutdown cleaning methods, this invention provides an online cleaning system for geothermal power plant steam turbines. The system uses a cleaning water pump to pressurize condensate, atomize it through nozzles, and inject it into the main steam pipeline. The steam carries droplets to dynamically clean the nozzles and blades of the geothermal power plant steam turbine in real time, achieving dynamic removal of scale without shutting down the plant. This solves the problems of efficiency loss and abnormal vibration caused by scale buildup. Furthermore, a flow meter and needle valve are used to precisely control the cleaning intensity, preventing excessive rinsing and damage to the blades.

[0006] This utility model provides an online cleaning system for a geothermal power plant turbine, including a condensate system. The condensate system is connected to one end of an inlet pipe, and the other end of the inlet pipe is connected to a cleaning water pump. The cleaning water pump is connected to one end of a first outlet pipe, and the other end of the first outlet pipe is connected to one end of a second outlet pipe and a recirculation pipe, respectively.

[0007] A flow meter and a needle valve are installed on the second outlet pipe. The other end of the second outlet pipe is connected to multiple cleaning branches. A nozzle is installed at the end of the cleaning branch. The nozzle is connected to the main steam pipe, which is connected to the steam turbine of the geothermal power station.

[0008] The other end of the recirculation pipe is connected to the condensate system.

[0009] Furthermore, along the flow direction of the condensate, an inlet isolation valve and a differential pressure transmitter are sequentially installed on the inlet pipe; the differential pressure transmitter is connected in parallel with the inlet pipe through a connecting pipe, and an inlet filter is installed on the inlet pipe connected in parallel with the differential pressure transmitter.

[0010] An inlet isolation valve is installed on the inlet pipe along the condensate flow direction. During system maintenance, repair, or malfunction, it cuts off the condensate flow, isolating and protecting downstream equipment, including the differential pressure transmitter, to prevent condensate leakage. The differential pressure transmitter is connected in parallel to part of the inlet pipe via a connecting pipe. Its function is to measure the pressure difference before and after the inlet filter in the inlet pipe. Based on the monitored pressure difference, the condensate flow status and filter operation can be understood. If the pressure difference is abnormal, it can be used to determine whether the inlet filter is clogged or whether there are foreign objects obstructing the water flow in the pipe. This provides crucial information for system fault diagnosis and maintenance, ensuring the normal operation of the system.

[0011] Furthermore, the imported filter is connected to the sewage pipe, and a filter drain valve is installed on the sewage pipe. The end of the sewage pipe leads to the sewage pool.

[0012] Once a certain amount of impurities accumulates in the inlet filter, the impurities can be discharged into the sewage pipe along with the condensate by opening the filter's drain valve. The end of the sewage pipe leads to a sewage tank to collect this condensate containing impurities, preventing direct discharge of wastewater and avoiding environmental pollution. It also facilitates centralized treatment or recycling of wastewater, achieving environmentally friendly and sustainable operation of the system.

[0013] Furthermore, a first pressure gauge is installed on the inlet pipe near the cleaning water pump, a second pressure gauge is installed on the first outlet pipe near the cleaning water pump, and a third pressure gauge is installed on the second outlet pipe.

[0014] A first pressure gauge is installed on the inlet pipe near the cleaning water pump to monitor the pressure at the pump in real time. This allows for understanding the inlet water pressure, determining whether the condensate supply is normal, and identifying any abnormalities such as excessively low or high pressure. This ensures the cleaning water pump can draw in condensate under appropriate pressure conditions. A second pressure gauge is installed on the first outlet pipe to monitor the outlet pressure of the cleaning water pump, reflecting its operating status and output pressure. This information can be used to determine whether the pump is operating normally, whether it has reached the expected pressure output, and whether there are any blockages or leaks in the piping system. A third pressure gauge is installed on the second outlet pipe primarily to monitor the pressure there. Comparing the readings with other pressure gauges helps analyze the balance of pressure distribution across different pipes in the entire system. This, in turn, helps determine the stability of the online cleaning system and identify any potential malfunctions caused by localized pressure anomalies, providing a basis for system maintenance and troubleshooting.

[0015] Furthermore, along the flow direction of the condensate, an outlet check valve and an outlet isolation valve are sequentially installed on the first outlet pipe.

[0016] The outlet check valve can effectively prevent cleaning water from flowing back from the first outlet pipe to the cleaning water pump, ensuring that the water flow always follows the design direction, avoiding backflow from damaging the water pump, and ensuring the stable operation of the cleaning system.

[0017] Furthermore, the second outlet pipe is connected to the inlet of the electric isolation valve, and the outlet of the electric isolation valve is connected to the cleaning branch.

[0018] The electrically operated isolation valve enables remote control or automated operation, facilitating the quick and accurate disconnection or connection of water flow between the second outlet pipe and the cleaning branch under various operating conditions. When maintenance or repair of the geothermal power plant turbine connected to the cleaning branch is required, or when a fault necessitates isolation, the electrically operated isolation valve can be closed to prevent water from entering the cleaning branch. This avoids water flow affecting maintenance personnel during operation, prevents water leakage and waste, and ensures the normal operation of other parts of the system. Furthermore, during normal operation, a needle-type regulating valve is installed upstream of the electrically operated isolation valve to regulate the water flow rate in the cleaning branch. This allows for precise control of the amount of water entering the cleaning branch according to actual needs, improving the operational efficiency and flexibility of the entire online cleaning system.

[0019] Furthermore, manual isolation valves are installed on the cleaning branch lines.

[0020] Furthermore, venting valves are installed between the manual isolation valves of different cleaning branches.

[0021] The purpose of setting up the vent valve is to release the air accumulated in the pipeline before starting or during the operation of the online cleaning system. This is to prevent air accumulation from affecting the normal flow of condensate, prevent air lock, ensure that the system can operate stably and efficiently, and allow condensate to pass smoothly through the nozzles to clean the geothermal power plant turbine online.

[0022] Furthermore, there are two cleaning branches, with two nozzles connected to the end of each cleaning branch. The two nozzles of the same cleaning branch are set at radially opposite positions on the main steam pipe.

[0023] Based on the actual operation of the online cleaning system, two cleaning branches are set up, with two nozzles connected to the end of each cleaning branch. This can effectively clean the steam turbine of the geothermal power plant while minimizing costs.

[0024] Furthermore, a recirculation isolation valve and a throttling orifice plate are installed on the recirculation pipeline.

[0025] A recirculation isolation valve is installed on the recirculation pipeline to control whether the condensate is recirculated. The function of the recirculation pipeline is to protect the cleaning water pump and prevent phenomena such as pump stalling, water temperature rise and vaporization when the cleaning water pump is just started or running at extremely low load. The orifice plate is used to regulate the recirculation flow rate to achieve safe operation of the cleaning water pump and system stability.

[0026] The beneficial effects of this utility model are as follows:

[0027] This invention provides an online cleaning system for geothermal power plant steam turbines. The system connects to a cleaning water pump via an inlet pipe through the condensate system. The first outlet pipe of the cleaning water pump splits into two branches—a second outlet pipe and a recirculation pipe. The flow rate of the second outlet pipe is precisely controlled by a flow meter and a needle valve. The flow is then connected to the main steam pipe through nozzles at the ends of multiple branch lines. This allows a large number of condensate droplets to be evenly carried by the steam into the geothermal power plant steam turbine. The mechanical friction between the droplets and the nozzle blades removes scale online. Simultaneously, the recirculation pipe allows some condensate to be recycled back to the condensate system, ensuring stable pressure in all pipes of the online cleaning system and preventing the cleaning water pump from stalling. This online cleaning system can dynamically remove scale without shutting down the turbine, ensuring the operating efficiency and safety of the geothermal power plant steam turbine and significantly extending the continuous operating cycle. Attached Figure Description

[0028] To more clearly illustrate the technical solution of this utility model, the drawings used in the description will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the online cleaning system for a geothermal power plant turbine according to this utility model.

[0030] In the diagram, 1-inlet pipe, 2-inlet isolation valve, 3-inlet filter, 4-cleaning water pump, 5-outlet check valve, 6-outlet isolation valve, 7-recirculation pipe, 8-recirculation isolation valve, 9-orifice plate, 10-second outlet pipe, 11-flow meter, 12-needle valve, 13-electric isolation valve, 14-vent valve, 15-manual isolation valve, 16-nozzle, 17-main steam pipe, 18-filter drain valve, 19-condensate system, 20-geothermal power plant turbine, 21-differential pressure transmitter, 22-first outlet pipe, 23-first pressure gauge, 24-second pressure gauge, 25-third pressure gauge. Detailed Implementation

[0031] To make the objectives, features, and advantages of this utility model more apparent and understandable, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings of the specific embodiments. Obviously, the embodiments described below are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this patent, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this patent.

[0032] Example 1

[0033] An online cleaning system for a geothermal power plant turbine includes a condensate system 19, which is connected to an inlet pipe 1. Along the flow direction of the condensate, an inlet isolation valve 2 and a differential pressure transmitter 21 are sequentially installed on the inlet pipe 1. The differential pressure transmitter 21 is connected in parallel with the inlet pipe 1 through a connecting pipe. An inlet filter 3 is installed on the inlet pipe 1 connected in parallel with the differential pressure transmitter 21. The inlet filter 3 is connected to a sewage pipe. A filter sewage valve 18 is installed on the sewage pipe. The end of the sewage pipe leads to a sewage tank.

[0034] The other end of the inlet pipe 1 is connected to the cleaning water pump 4. The cleaning water pump 4 is connected to the first outlet pipe 22. A first pressure gauge 23 is installed on the inlet pipe 1 near the cleaning water pump 4. A second pressure gauge 24 is installed on the first outlet pipe 22 near the cleaning water pump 4. Along the flow direction of the condensate, the second pressure gauge 24, the outlet check valve 5 and the outlet isolation valve 6 are installed in sequence on the first outlet pipe 22. The other end of the first outlet pipe 22 is connected to the second outlet pipe 10 and one end of the recirculation pipe 7, respectively.

[0035] A flow meter 11, a needle valve 12, and a third pressure gauge 25 are installed on the second outlet pipe 10. An electric isolation valve 13 is installed on the second outlet pipe 10, and then it is connected to two cleaning branches. Each cleaning branch is equipped with a manual isolation valve 15. A vent valve 14 is installed between the manual isolation valves 15 of the two cleaning branches. Two nozzles 16 are connected to the end of each cleaning branch. The two nozzles 16 on the same cleaning branch are set at radially opposite positions on the main steam pipe 17. The two cleaning branches are set sequentially along the steam flow direction. The main steam pipe 17 is connected to the steam turbine 20 of the geothermal power station.

[0036] The other end of the recirculation pipe 7 is connected to the condensate system 19, and a recirculation isolation valve 8 and a throttling orifice plate 9 are installed on the recirculation pipe 7.

[0037] Operating procedure for starting up the online cleaning system of a geothermal power plant turbine:

[0038] Before use, it is necessary to confirm that the load of the geothermal power plant turbine 20 is stable and above 90% of the rated load. This ensures that the condensate system 19 of the geothermal power plant turbine 20 can supply condensate normally, avoiding insufficient condensate supply and resulting in poor cleaning performance. Confirm that the inlet isolation valve 2 is closed, and check whether the differential pressure transmitter 21, the first pressure gauge 23, the second pressure gauge 24, the third pressure gauge 25, and the flow meter 11 are working properly. Check whether the inlet filter 3 is clean; if there are impurities, clean them first. At the same time, ensure that the filter drain valve 18 is closed, the drain pipe is securely connected, and the end leads to the drain tank. Check that the recirculation isolation valve 8 is closed, the electric isolation valve 13 is closed, the vent valve 14 is open, and all manual isolation valves 15 are closed.

[0039] Before using the online cleaning system of the geothermal power plant turbine for the first time, the needle valve 12 must be completely closed. In subsequent uses, only minor adjustments to the needle valve 12 are needed based on past experience and actual conditions; it is not necessary to open it from the completely closed state again. Open the inlet isolation valve 2 and the recirculation isolation valve 8, and start the cleaning water pump 4 to allow condensate to slowly flow into the inlet pipe 1. Observe the reading of the differential pressure transmitter 21 and monitor the pressure difference before and after the inlet filter 3 to determine if the inlet filter 3 is clogged. If the pressure difference exceeds the normal range, the filter drain valve 18 can be opened for drainage. After drainage, the filter drain valve 18 should be closed. After the condensate is pressurized by the cleaning water pump 4, part of it enters the recirculation pipe 7 at a minimum flow rate to prevent the cleaning water pump 4 from stalling; the other part flows through the second outlet pipe 10, through the flow meter 11, needle valve 12, electric isolation valve 13, and manual isolation valve 15, and then through the nozzle 16 into the main steam pipe 17. Open the bypass valve of the steam trap before the main steam valve and the bypass valve of the steam trap after the regulating valve of the geothermal power plant turbine 20 (these two valves are inside the geothermal power plant turbine 20) so as to drain the condensate entering the geothermal power plant turbine 20 in a timely manner.

[0040] According to the cleaning requirements, the flow rate of condensate in the second outlet pipe 10 is controlled by adjusting the needle valve 12. The flow rate of condensate in the second outlet pipe 10 is determined according to the severity of the nozzle blockage rate and is controlled between 0.5% and 2% of the rated flow rate of the main steam to avoid excessive condensate or prolonged cleaning that could lead to excessive wear or damage to the turbine blades.

[0041] After a period of time (determined based on actual cleaning results), close the electric isolation valve 13 and the manual isolation valve 15, stop the cleaning water pump 4, close the inlet isolation valve 2, open the filter drain valve 18, and drain the inlet filter 3. After draining, close the filter drain valve 18. Close the bypass valve of the steam trap before the main steam valve and the bypass valve of the steam trap after the regulating valve of the geothermal power plant turbine 20 (these two valves are inside the geothermal power plant turbine 20).

[0042] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An online cleaning system for a geothermal power plant turbine, comprising a condensate system (19), characterized in that, The condensate system (19) is connected to one end of the inlet pipe (1), the other end of the inlet pipe (1) is connected to the cleaning water pump (4), the cleaning water pump (4) is connected to one end of the first outlet pipe (22), and the other end of the first outlet pipe (22) is connected to one end of the second outlet pipe (10) and the recirculation pipe (7), respectively. A flow meter (11) and a needle valve (12) are installed on the second outlet pipe (10). The other end of the second outlet pipe (10) is connected to multiple cleaning branches. A nozzle (16) is installed at the end of the cleaning branch. The nozzle (16) is connected to the main steam pipe (17). The main steam pipe (17) is connected to the steam turbine (20) of the geothermal power station. The other end of the recirculation pipe (7) is connected to the condensate system (19).

2. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, Along the flow direction of condensate, an inlet isolation valve (2) and a differential pressure transmitter (21) are installed in sequence on the inlet pipe (1); the differential pressure transmitter (21) is connected in parallel with the inlet pipe (1) through a connecting pipe, and an inlet filter (3) is installed on the inlet pipe (1) connected in parallel with the differential pressure transmitter (21).

3. The online cleaning system for a geothermal power plant turbine as described in claim 2, characterized in that, The imported filter (3) is connected to the sewage pipe, and a filter drain valve (18) is installed on the sewage pipe. The end of the sewage pipe leads to the sewage pool.

4. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, A first pressure gauge (23) is installed on the inlet pipe (1) near the cleaning water pump (4), a second pressure gauge (24) is installed on the first outlet pipe (22) near the cleaning water pump (4), and a third pressure gauge (25) is installed on the second outlet pipe (10).

5. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, Along the flow direction of condensate, an outlet check valve (5) and an outlet isolation valve (6) are installed in sequence on the first outlet pipe (22).

6. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, The second outlet pipe (10) is connected to the inlet of the electric isolation valve (13), and the outlet of the electric isolation valve (13) is connected to the cleaning branch.

7. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, A manual isolation valve (15) is installed on the cleaning branch.

8. The online cleaning system for a geothermal power plant turbine as described in claim 7, characterized in that, A vent valve (14) is installed between the manual isolation valves (15) of different cleaning branches.

9. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, There are two cleaning branches, and the end of each cleaning branch is connected to two nozzles (16). The two nozzles (16) of the same cleaning branch are set at radially opposite positions on the main steam pipe (17).

10. The online cleaning system for a geothermal power plant turbine as described in claim 1, characterized in that, A recirculation isolation valve (8) and a throttling orifice plate (9) are installed on the recirculation pipeline (7).

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