The document discusses heat recovery steam generators (HRSGs) and cooling systems. An HRSG captures exhaust heat from a gas turbine to create steam for a steam turbine. It works by receiving exhaust gases from the gas turbine countercurrently to heat water and produce steam. The steam then drives the steam turbine. Cooling systems discussed include cooling towers, which cool water used in condensers by evaporation and heat transfer to air before recycling it. Condensers condense exhaust steam from steam turbines to maximize efficiency and convert it into pure water for reuse.

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 HRSG
 Water Cooling System
Ms. Mahum Jamil

2. Heat recovery steam Generator:
T S G Tr a i n i n g C e n t e r, L a h o r e
Objective:
A heat recovery steam generator
(HRSG) captures exhaust heat from
the gas turbine that would otherwise
escape through the exhaust stack.
The HRSG creates steam from the
gas turbine exhaust heat and delivers
it to the steam turbine.
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3. Heat recovery steam Generator:
T S G Tr a i n i n g C e n t e r, L a h o r e
Working Principle:
The HRSG receives the exhaust gases from the Gas Turbine
discharge.
The exhaust gas, flowing in the counter flow direction with
respect to the steam/water coils, cools down by transferring heat
to steam/water.
The flue gas temperature at the stack is about 111°C.
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4. Heat recovery steam Generator:
T S G Tr a i n i n g C e n t e r, L a h o r e
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5. Heat recovery steam Generator:
T S G Tr a i n i n g C e n t e r, L a h o r e
Types based on construction:
1-vertical
2- Horizontal
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6. Cooling Tower
T S G Tr a i n i n g C e n t e r, L a h o r e
Objective:
It may be noted that in cooling tower, the
water cools by
• Evaporation and
• Heat transfer to air
• In many towers 75% of cooling takes place
by evaporation and the remainder by heat
transfer.
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7. Cooling Tower
T S G Tr a i n i n g C e n t e r, L a h o r e
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8. Cooling Tower
T S G Tr a i n i n g C e n t e r, L a h o r e
Cools the warm water discharged from the condenser and feed the cooled
water back to the condenser.
Warm water from the exit of condenser is collected at the top of tower and
allowed to trickle down through these troughs or baffles by gravity.
Meanwhile, cold air is drawn from the bottom of tower and forced up in
opposite direction to trickling droplets of water.
Thus heat transfer takes place between warm water and cool atmospheric
air. As a result water gets cooled which is extracted out and pumped back to
condenser for recirculation.
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9. Steam Condenser
T S G Tr a i n i n g C e n t e r, L a h o r e
Objective:
The purpose of a surface condenser is
to condense the exhaust steam from a
steam turbine to obtain maximum
efficiency, and also to convert the
turbine exhaust steam into pure water
(referred to as steam condensate) so
that it may be reused in the HRSG.
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10. Steam Condenser
T S G Tr a i n i n g C e n t e r, L a h o r e
Working principle:
• A flow of cooling water is continuously circulating from the condenser
inside a steam condenser to the cooling tower and the cooling tower to the
condenser.
• When low-pressure exhaust steam leaves the turbine and passes through
the condenser, it loses the heat and condenses into water.
• The circulating cooling water performs the extraction of the heat from the
steam.
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11. Steam Condenser
T S G Tr a i n i n g C e n t e r, L a h o r e
Why It Is Required?
The purpose of a surface condenser is to
condense the exhaust steam from a steam
turbine to obtain maximum efficiency, and
also to convert the turbine exhaust steam
into pure water (referred to as steam
condensate) so that it may be reused in the
HRSG.
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