Description
GE DS200TCQAF1AFB module
Contact: Mr. Lai
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Detailed explanation of scaling causes and treatment methods of steam turbine condenser
Condenser equipment is an important part of steam turbine unit. Its working performance directly affects the safety, reliability, stability and economy of the whole steam turbine unit. The vacuum degree of condenser is an important indicator of steam turbine operation, and also a major assessment indicator reflecting the comprehensive performance of condenser. The vacuum level of the condenser has a direct impact on the economy of the steam turbine generator unit, and in serious cases, directly affects the generating load of the unit. Therefore, keep the condenser in good operating condition and ensure the most favorable vacuum of the condenser; It is an important part of energy saving in power plants.
1、 Equipment overviewGE DS200TCQAF1AFB
Two sets of 12MW medium-temperature and medium-pressure condensing steam turbine generator units in a certain plant have the following condenser parameters:
Model: N-1000-7 Type: split two-pass surface type
Cooling area 1000m2 Cooling water volume 3000/h
Maximum allowable water pressure in the water chamber: 0.34MPa Water resistance: 265kPa
Net weight: 22.2t Operating weight: 35.8t
Specification of cooling stainless steel pipe: 20 * 0.7 * 4562mm
Quantity: 3540 pieces Material: 304
2、 Operation status
The vacuum of steam turbine is gradually low during operation, the vacuum value is gradually reduced from – 88 kpa to – 77 kpa, the end difference is increased from 11 ℃ to 34 ℃, the circulating water supply temperature is less than 30 ℃, the circulating water volume is more than 6000 m3/h, the circulating ratio is more than 60, and the circulating water temperature and flow fully meet the operation requirements. The long-term low vacuum operation will affect the efficiency of the unit. If the vacuum continues to decrease, it will threaten the safe operation of the unit. In order to ensure that the unit operates within the safe range, the load of the generator is reduced, with the maximum load of 80% of the rated load, which seriously affects the efficiency of the unit.
3、 Existing problems and cause analysis
The main characteristics of condenser vacuum drop are as follows: 1. The exhaust steam temperature rises; 2. Condensate supercooling increases; 3. The indication of vacuum gauge decreases; 4. The condenser end difference increases; 5. The unit vibrates; 6. Under the condition that the opening of the regulating valve remains unchanged, the load of the steam turbine decreases.
Cause analysis of condenser vacuum drop: the causes of condenser vacuum drop of steam turbine can be roughly divided into external causes and internal causes: external causes mainly include interruption or insufficiency of circulating water volume, rise of circulating water temperature, interruption of rear shaft seal steam supply, failure of air extractor, etc; Internal causes mainly include full water (or rising water level) of condenser, scaling of condenser, deterioration of heat transfer, tightness of condenser vacuum system, air inflow caused by steam side leakage, etc. The most common cause is the scaling in the condenser tube, which is mainly biological slime and carbonate hard scale, and some are phosphate and silicate hard scale. Condenser scaling seriously affects the condensation effect, and affects the end difference, vacuum degree and power generation. Scaling shortens the service life and normal output of condenser equipment. If the scale of condenser tube reaches 0.3 mm, the efficiency of steam turbine will be affected; More than 0.5mm can affect the output of steam turbine, and corrosion leakage is mainly caused by scaling of circulating water. Scaling leads to a significant reduction in the working efficiency of the condenser and affects the operation economy and safety of the unit.
From the analysis of operation, it is judged that it is caused by condenser scaling; Take advantage of the turbine maintenance opportunity, open the condenser manhole, check the condenser cooling water pipe, check that the scaling thickness of the upper condenser cooling pipe is greater than 1mm, and the lower part is gradually reduced to 0.5mm (the reason is that the upper condensed steam temperature is high, and the lower condensed steam temperature has decreased), and the water outlet side is significantly more serious than the inlet side.
Causes of scaling of steam turbine:
1. The design rated steam exhaust load of the power generation condenser is 50/h, the current steam exhaust load is 58-64 t/h, and the overload operation is nearly 20%.
2. The low-pressure heater is out of operation according to the requirements of the boiler, and~5t/h of steam that should have entered the low-pressure heater enters the condenser, causing the condenser to overload.
3. Since the boiler requires the main steam pressure not to be higher than 3.7MPa, the steam pressure sent to the steam turbine is only 3.2MPa, which is 3.42MPa lower than the design rated pressure. At the rated load, 2tVh more steam is consumed, and the condenser load is increased by 2t/h.
4. In order to complete the power generation, the unit load is controlled at 12.5MW, which consumes 2tVh more steam than the rated 12MW, and the condenser load is increased by 2t/h.
5. The increased steam intake of the above items will further affect the vacuum reduction of the condenser. Under the requirement of ensuring that the unit is loaded, the steam intake will also increase relatively, forming a reverse cycle, which will also cause the end difference to rise.
6. The supervision of circulating water quality is not in place, and the turbidity and concentration ratio increase frequently. The working environment of the cooling tower is poor, the water turbidity is high, the system evaporation is large, the concentration is fast, and the sewage discharge is small. Insufficient dosage of bactericide, scale inhibitor and dispersant and high hardness of source water will cause scaling of condenser cooling pipe.
4、 Solution
Condenser scaling cleaning methods are divided into physical cleaning and chemical cleaning. Physical cleaning usually adopts four methods:
1. Manual poking and washing. It is a manual reciprocating stabbing and brushing of the condenser tube with a stabbing bar. In order to remove the scale in the pipe, because it is only manual poking and washing, only soft scale and a small amount of hard scale can be removed, which is not thorough and labor intensive, and cannot achieve satisfactory results. Moreover, the mechanical damage to the cooling water pipe is relatively serious, and the old scale that has not been removed is used as crystal nucleus, which accelerates the scaling speed; 2. Rubber ball cleaning. It adopts the way of parallel connection between rubber ball system and circulating water system. It needs to be put into use frequently, but only soft scale can be removed, which can not play a role in the formation of hard scale.
3. High pressure water jet cleaning. This kind of cleaning effect is good. It uses high pressure water spray to remove most of the dirt in the pipe through the pipeline of the equipment to be cleaned. However, due to high labor intensity, low descaling rate, long cleaning time, high pressure causes serious mechanical damage to condenser tubes.
4. Chemical cleaning of condenser scaling. The main purpose of chemical cleaning is to remove calcium carbonate scale on the surface of condenser. Chemical cleaning of condenser has the following advantages: First, the effect of removing hard scale is good, and the rate of chemical cleaning is high. Chemical cleaning can achieve the goal of completely removing dirt, and its scale removal uniformity is consistent, and the effect is good. 2、 The cleaning time is short. Because the main components of the fouling on the condenser copper pipe are carbonate and sludge, the chemical cleaning method is applied, which has short cleaning time and simple process.
After comprehensive evaluation, it is decided to adopt chemical cleaning method. The specific scheme of chemical cleaning is:
The main process of circulating water system cleaning: descaling treatment → water replacement → hanging solid agent
Chemical cleaning agent dosage:
GE 369B1860G0030
GE 369B1860G0028
GE 369B1860G0026
GE 323A2419P3
GE 04240FD11234A
GE 04220FL11232A
GE IS420ESWBH3A
GE IS200TRPGH1BDE
GE IS200JPDFG2AED
GE HE693CAN501D
GE F650-G-N-A-B-F-2-G-1-HI-C-E
GE DS3820LT4AICIA
GE DS3800XPEX1B1A
GE DS3800NHVK1A1A
GE DS3800NGDC1B1A
GE DS3800DFXA1B1C
GE DS215TCQAG1BZZ01A
GE DS215TCQAG1BZZ01A
GE DS215TCDAG1BZZ01A
GE DS215KLDBG1AZZ03A
GE DS2020UCOCN1G1A
GE DS2020FECNRX015A
GE DS2020FECNRP025A
GE DS200TCTGG1AFF
GE DS200TCRAG1ACC
GE DS200TCQCG1BKG
GE DS200TCQCG1BKG
GE DS200TCQCG1BHF
GE DS200TCQCG1BGF
GE DS200TCQAG1BHF
GE DS200TCQAG1BFE
GE DS200TCQAG1BED
GE DS200TCQAG1BEC/DS215TCQAG1BZZ01A
GE DS200TCPSG1ARE
GE DS200TCPDG2B
GE DS200TCEBG1ACE
GE DS200TCEBG1ACD
GE DS200TCEAG1BTF
GE DS200TCEAG1BTF
GE DS200TCEAG1BSF/DS215TCEAG1BZZ01A
GE DS200TCEAG1BSF
GE DS200TCEAG1BNE
GE DS200TCEAG1ACB
GE DS200TCDAH1BJE
GE DS200TCDAH1BHE
GE DS200TCDAG1BDB/DS215TCDAG1BZZ01A
GE DS200TCDAG1BDB
GE DS200TCCAG1BAA
GE DS200TBQGG1ABB
GE DS200TBQDG1AFF
GE DS200TBQCG1ABB
Company advantage service:
1.Has been engaged in industrial control industry for a long time, with a large number of inventories.
2.Industry leading, price advantage, quality assurance
3.Diversified models and products, and all kinds of rare and discontinued products
4.15 days free replacement for quality problems
1.Has been engaged in industrial control industry for a long time, with a large number of inventories.
2.Industry leading, price advantage, quality assurance
3.Diversified models and products, and all kinds of rare and discontinued products
4.15 days free replacement for quality problems
All kinds of module card driver controller servo motor servo motor embedded card wires and cables Power module control module is applicable to steel, hydropower, nuclear power, power generation, glass factory, tire factory, rubber, thermal power, paper making, shipping, navigation, etc
ABB — AC 800M controller, Bailey, PM866 controller, IGCT silicon controlled 5SHY 3BHB01 3BHE00 3HNA00 DSQC series
BENTLY — 3500 system/proximitor, front and rear card, sensor, probe, cable 3500/20 3500/61 3500/05-01-02-00-001 3500/40M 176449-01 3500/22M 138607-01
Emerson — modbus card, power panel, controller, power supply, base, power module, switch 1C31,5X00, CE400, A6500-UM, SE3008,1B300,1X00,
EPRO — PR6423 PR6424 PR6425 PR6426 PR9376 PR9268 Data acquisition module, probe, speed sensor, vibration sensor
FOXBORO — FCP270 FCP280 FCM10EF FBM207 P0914TD CP40B FBI10E FBM02 FBM202 FBM207B P0400HE Thermal resistance input/output module, power module, communication module, cable, controller, switch
GE —- IS200/215/220/230/420 DS200/215 IC693/695/697/698 VMICPCI VMIVME 369-HI-R-M-0-0-E 469 module, air switch, I/O module, display, CPU module, power module, converter, CPU board, Ethernet module, integrated protection device, power module, gas turbine card
HIMA — F3 AIO 8/4 01 F3231 F8627X Z7116 F8621A 984862160 F3236 F6217 F7553 DI module, processor module, AI card, pulse encoder
Honeywell — Secure digital output card, program module, analog input card, CPU module, FIM card
MOOG — D136-001-007 Servo valve, controller, module
NI — SCXI-1100 PCI – PXIE – PCIE – SBRIO – CFP-AO-210 USB-6525 Information Acquisition Card, PXI Module, Card
Westinghouse — RTD thermal resistance input module, AI/AO/DI/DO module, power module, control module, base module
Woodward — 9907-164 5466-258 8200-1300 9907-149 9907-838 EASYGEN-3500-5/P2 8440-2145 Regulator, module, controller, governor
YOKOGAWA – Servo module, control cabinet node unit
Main products:
PLC, DCS, CPU module, communication module, input/output module (AI/AO/DI/DO), power module, silicon controlled module, terminal module, PXI module, servo drive, servo motor, industrial display screen, industrial keyboard, controller, encoder, regulator, sensor, I/O board, counting board, optical fiber interface board, acquisition card, gas turbine card, FIM card and other automatic spare parts
ABB — AC 800M controller, Bailey, PM866 controller, IGCT silicon controlled 5SHY 3BHB01 3BHE00 3HNA00 DSQC series
BENTLY — 3500 system/proximitor, front and rear card, sensor, probe, cable 3500/20 3500/61 3500/05-01-02-00-001 3500/40M 176449-01 3500/22M 138607-01
Emerson — modbus card, power panel, controller, power supply, base, power module, switch 1C31,5X00, CE400, A6500-UM, SE3008,1B300,1X00,
EPRO — PR6423 PR6424 PR6425 PR6426 PR9376 PR9268 Data acquisition module, probe, speed sensor, vibration sensor
FOXBORO — FCP270 FCP280 FCM10EF FBM207 P0914TD CP40B FBI10E FBM02 FBM202 FBM207B P0400HE Thermal resistance input/output module, power module, communication module, cable, controller, switch
GE —- IS200/215/220/230/420 DS200/215 IC693/695/697/698 VMICPCI VMIVME 369-HI-R-M-0-0-E 469 module, air switch, I/O module, display, CPU module, power module, converter, CPU board, Ethernet module, integrated protection device, power module, gas turbine card
HIMA — F3 AIO 8/4 01 F3231 F8627X Z7116 F8621A 984862160 F3236 F6217 F7553 DI module, processor module, AI card, pulse encoder
Honeywell — Secure digital output card, program module, analog input card, CPU module, FIM card
MOOG — D136-001-007 Servo valve, controller, module
NI — SCXI-1100 PCI – PXIE – PCIE – SBRIO – CFP-AO-210 USB-6525 Information Acquisition Card, PXI Module, Card
Westinghouse — RTD thermal resistance input module, AI/AO/DI/DO module, power module, control module, base module
Woodward — 9907-164 5466-258 8200-1300 9907-149 9907-838 EASYGEN-3500-5/P2 8440-2145 Regulator, module, controller, governor
YOKOGAWA – Servo module, control cabinet node unit
Main products:
PLC, DCS, CPU module, communication module, input/output module (AI/AO/DI/DO), power module, silicon controlled module, terminal module, PXI module, servo drive, servo motor, industrial display screen, industrial keyboard, controller, encoder, regulator, sensor, I/O board, counting board, optical fiber interface board, acquisition card, gas turbine card, FIM card and other automatic spare parts
