Steam Condense Performance and Loss Diagnostic

Pichai Chaibamrung

IntroductionThis report is intent to guide engineer, operator, or

technician to diagnose poor condenser vacuum in thermal power plant. A slightly increase condenser pressure result in a huge loss due to increasing plant heat rate. This guidance can be help involving person to fast and accurately analyze the root causes of the losses

Surface CondenserShell and tube heat exchangerConnect to steam turbine exhaust To convert low energy exhaust steam to water to

reuse in power boilerOperating below atmospheric pressure Use cooling water to extract heat from low

energy exhaust steam

Important of condenser pressureMore vacuum pressure more useful energy

convertedMore useful energy converted, less raw energy is

need

T

S

Lowering condenser pressure more energy converted in steam turbine

Expected Design Condenser Pressure

Steam load

Q -Is your current operating pressure is good? -How you know?

A :You have to compare with expected design pressure at each load and specific cooling water temperature

Example, Steam load 72 T/H Cooling water inlet temperature 32 CCurrent operating pressure -0.86 bargDesign operating pressure -0.88 barg

What is the root cause?

Current operating

Design operating

Poor vacuum, What is result from?Less cooling water flow rateFouling on tubeIncondensable gas in condenser shellOver heat duty

How do we know what the cause is ?

DefinitionTI = exhaust steam temperature TO = condensate temperatureT1 = cooling water inlet temperatureT2 = cooling water outlet temperatureTI – T2 = terminal temperature different (TTD)T2-T1 = temperature rise (TR)TO - TI = sub-cooling temperature (TS)

Less cooling water flow rate

Fouling on tube

Incondensable gas in condenser shell

Over heat duty

Conclusion