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The 2 nd annual Air-Cooled Condenser User’s Group Meeting. Air-Cooled Condensate Polishing in China. WenhuaTian Huiyong He Xi’an Thermal Power Research Institute Co Ltd.(TPRI), China September 28-29, 2010 Pueblo. CONTEXTS. I. Introduction of TPRI

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The 2nd annual Air-Cooled Condenser User’s Group Meeting

Air-Cooled Condensate Polishing in China

WenhuaTian Huiyong He

Xi’an Thermal Power Research Institute

Co Ltd.(TPRI), China

September 28-29, 2010

Pueblo


Contexts
CONTEXTS

I. Introduction of TPRI

II. Developments of ACCs in China

III. Carbon Dioxide in ACCs

IV. DO Controlling in ACCs

V. Case of Indirect ACCs




Outline

The distribution of coal and water resources in China is asymmetric; coal-rich regions typically lack water and vice versa

Because of its significant water-saving advantage, ACC is suitable for drought-prone regions in northern China. So the government of China required that all the new built coal power plants should be used ACCs in drought-prone regions after 2002

The use of ACCs has increased rapidly in China within the past five years

Outline


Development of accs

The total capacity of ACCs was about 24,000MW by 2007 asymmetric; coal-rich regions typically lack water and vice versa

The percentage of ACCs was 4.3%(Total capacity of coal power plant was 554,000 MW)

The number of constructing sub-critical ACC plants was 47, and the capacity was 46,000 MW (2008 ~ 2009)

Development of ACCs


It is estimated that the total capacity will reach 1,200,000MW until 2015 in China

Capacity of coal power plant will be 820,000MW

Capacity of ACCs will surpass 100,000MW and occupy 12%

Foreground


Direct ACCs were the majority, occupied 93% in 2007 1,200,000MW until 2015 in China

Indirect ACCs developed rapidly after 2008. Up to now, the operation capacity is 4,200MW, and other units with 16,800MW capacity is constructing

Ratio of Direct & Indirect


The percentage of different CPP(2009) 1,200,000MW until 2015 in China


Direct ACCs were the majority, occupied 93% in 2007 1,200,000MW until 2015 in China

Indirect ACCs developed rapidly after 2008. Up to now, the operation capacity is 4,200MW, and other units with 16,800MW capacity is constructing

Ratio of Direct & Indirect


Dalater Power Plant 1,200,000MW until 2015 in China( 4×600MW,Inner Mogolia)


Powdered resin filter 1,200,000MW until 2015 in China


Datang Tuoketuo Power Plant 1,200,000MW until 2015 in China( 4×600MW,Inner Mogolia)


Unit 5 high-speed cation bed 1,200,000MW until 2015 in China


S 1,200,000MW until 2015 in Chinaeparated bed in Jingjie power plant (4×600MW,Shaanxi)


Carbon dioxide in accs
Carbon Dioxide in ACCs 1,200,000MW until 2015 in China


Analyzer method instrument
Analyzer method & Instrument 1,200,000MW until 2015 in China

Because carbon dioxide in high pure water such as condensate is as low as μg/L(ppb) level , it is difficult to sample and determine.

Trace carbon dioxide analyzer(Sentry Co. ) can measure carbon dioxide in high pure water as low as ppb level on-line.

Advantages:

(1) convenient and quick testing process

(2) high accuracy, good repeatability and high sensitivity

Standard:

D 4519-94(Reapproved 2005)by ASTM


Trace carbon dioxide analyzer(Sentry Co. ) 1,200,000MW until 2015 in China


Determination Methods 1,200,000MW until 2015 in China

This test method measures the electrical conductivity of high purity water through a cation exchanger in the hydrogen form, then through an electric reboiler. The effluent was boiled at atmospheric boiling water temperature after acidic (volatile) gas removal. subsequently, it was cooled at 25℃. Passage through the cation resin replaces cations (including ammonia and amines)in the water with hydrogen ions. Two conductivity cells located in the instrument provide measurements of the cation conductivity at the incoming sample temperature, and the effluent conductivity at 25℃.

In order to obtain the carbon dioxide, subtract the conductivity of pure water (0.055μS/cm) from the conductivity of the final effluent cell. Then deduct this value from the cation conductivity obtained from the cell immediately after the cation exchanger resin. Use this adjusted conductivity value to look up the concentration of volatiles expressed as a concentration of carbon dioxide in Table.


Tongchuan Power Plant 1,200,000MW until 2015 in China

(2×600MW,Shaanxi Province)

Powdex of Tongchuan Power Plant


Shangan Power Plant 1,200,000MW until 2015 in China

(2×600MW, Hebei Province)

CA-AN Bed of Shangan Power Plant


Determination Results 1,200,000MW until 2015 in China

  • At the same pH condition, the higher level of CO2 , the higher level of Fe in the condensate

  • CO2 recycles in plant A, but it is removed in plant B by separated beds in plant B

  • It is important to control the level of CO2 , it will reduce corrosion of metals in ACCs.


Do controlling in accs
DO Controlling in ACCs 1,200,000MW until 2015 in China


DO in condense will make iron corroded in ACCs, so the limit DO concentration is 100ppb in China

The operational ACCs in condense often surpass the limit of 100ppb

Determination of DO


Zhaoguang Power Plant DO concentration is 100ppb in China

(2×300MW+2×600MW,

Shanxi Province)

Yushe Power Plant

(2×300MW,Shanxi Province)


Wuxiang Power Plant DO concentration is 100ppb in China

(2×600MW,Shanxi Province)

Hejin Power Plant

(2×300MW,Shanxi Province)


Determination results of DO DO concentration is 100ppb in China

The reason of high DO in condensate:

1. Vacuum system is too large that will lead to air leakage in ACCs.

2. DO in make-up water is too high. For example, it is 800 ppb in some power plant .


Strengthen the welding management and improve its quality, try to decrease the air leakage of vacuum

System retrofitting----Case

Methodsto decrease DO


DO in condensate after retrofitting try to decrease the air leakage of vacuum


Case of indirect accs
Case of Indirect ACCs try to decrease the air leakage of vacuum


Yangcheng Power Plant is located in Shanxi province in China.

The first stage project are 6×350MW subcritical WCCs,which was completed at 1997.8.

The second stage project are 2×600MW subcritical indirect ACCs named SCAL, which began to construct at 2005.5.18 and completed at 2007.9.

Basic Information

  • The SCAL ACCs is produced by EGI company(Hungary), and it is more like the combination of Harmon’s no tower system and Heller’s cooling tower.


Cooled water recycles closely during operation, no water consumption

High heat -exchange efficiency

The corrosion rate of condenser can be controlled by adjusting pH in recycled water in order to prolong service cycle time of condenser

Less power consumption

The volume of air cooling tower is small

Simple system, convenient operation and less capital construction investment

Features of SCAL indirect ACCs


Unit 7 & 8 of Yangcheng Power Plant are indirect ACCs. 3 sets of powdex are used for each CPP.

Powdex shows good filtration abillity for crud, but its desalination capacity is weak, so steam quality of the units didn’t reach the standard for most of running time.

In order to improve the steam quality, retrofitting of CPP was carried out. 2 high-speed mixed beds were added after powdex

The retrofitting has been successfully completed and put into operation in March 2009, and achieved desired results.

CPP Introduction


Steam quality of unit 8 before retrofitting sets of powdex are used for each CPP.

2007.8-2008.9

SiO2, organism, CO2 and other impurities in condensate couldn’t be removed after powdex. It is just depended on boiler blowdown. This is the main reason of high conductivity in steam.


Steam quality of unit 8 after retrofitting sets of powdex are used for each CPP.

2009.3

After retrofitting, conductivity in the system decreased clearly. The effluent quality of high speed mixed beds is still good after nearly 1 month operation. It achieved the desired results.


Thanks for your attention sets of powdex are used for each CPP.!


Welcome to China sets of powdex are used for each CPP.!Welcome to Xian!

Welcome to TPRI!


Wenhua Tian sets of powdex are used for each CPP.:86-029-82102246(Office)

86-13991302260

Email:[email protected]

Huiyong He:86-029-82102570(Office)

86-13609111635

Email:[email protected]


Mixed bed
Mixed Bed sets of powdex are used for each CPP.

Cylindrical MB


Strengthen the welding management and improve its quality, try to decrease the air leakage of vacuum

System retrofitting----Case

The condensate tank was combined to the exhaust air cooling device. After through the nozzle, the makeup water goes to the throat of exhaust device. It can lead to an increase of the secondary removal of oxygen in returned condensate.

Methodsto decrease DO


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