Water Cycle

Tanj njun ung g Ja J ati B Tr Tr ain inii ng WATER CYCLE Coal Fired Boiler Design & Performance.1

P.T. Central Java Power  Tanjung Jati B Units 1 & 2 2 x 660MW (net)

Boiler

Precipitator  

FGD Absorber  Coal Fired Boiler Design Tanjung Jati& Performance.2 B Training

Coal Fired Boiler  Design & Performance

WATER CYCLE OVERVIEW

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Boiler Circulation Goal

The goal is to generate the required steam flow at the required outlet conditions while providing adequate cooling to protect the furnace.

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 Adequate Boiler Water Circulation is Important…

Maximize the life of the Furnace tubes Maximize Boiler efficiency  Avoid internal tube scaling, plugging of tubes and failures

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How do we achieve our goal?

1. Maintain a good water treatment program. 2. Do not overfire boiler under certain steam load conditions. Over-firing at low boiler pressures and low boiler load (start-up) is a common mistake.

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Natural Circulation Principle

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Boiling

(Good)

(Bad)

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The Circulation Loop

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Water Cycle

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Water Cycle • Feedwater enters the Economizer through the feedwater stop and check valves, and passes through the economizer tubes, the economizer stringer support tubes, and on to the outlet headers. • From

the Economizer  outlet header, feedwater is piped into both ends of the Steam Drum and is distributed along the drum length by means of a perforated feedpipe.

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Steam/Water Cycle Steam Drum Internals Steam Drum

Steam Outlet

Primary Scrubbers Secondary Scrubbers Feedwater  Piping

Cyclone Separators or “ cans” Vortex Eliminator 

Downcomers (x3)

Feedwater  Inlet (at end of Drum)

Coal Fired Boiler Design & Performance.12 Tanj ung J ati B Training

Water Cycle • Feedwater mixes with the hot water in the Steam Drum. • Water from the steam drum flows down the Downcomers located outside the boiler. • Water from the downcomer is distributed to the furnace wall tubes via the inlet supply tubes and headers. • Then, the boiler water  flows up the furnace tubes to the steam drum.

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Water Cycle

STEAM DRUM

FURNACE REARWALL HEADER

ECONOMIZER OUTLET HEADERS

FURNACE FRONT WALL HEADER

DOWNCOMERS

ECONOMIZER INLET HEADERS

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Steam Drum • In the Steam Drum, the steam is separated from the steam/water mixture by way of Cyclone Separators and Scrubbers. • The “ dry” steam passes through multiple connections to the headers supplying the furnace roof tubes and convection pass wall tubes and then to the primary superheater inlet header. STEAM OUTLET

SCRUBBERS

CYCLONE SEPARATORS

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Coal Fired Boiler  Design & Performance

WATER CYLCLE (END)

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