Steam power plants introduction by Rana Saifullah Khan

POWER PLANTS

POWER PLANTS

• A POWER PLANT IS A ASSEMBLY OF SYSTEMS AND SUBSYSTEMS TO GENERATE ELECTRICITY i.e POWER WITH ECONOMY AND REQUIREMENTS.

• ALL THE EQUIPMENT INCLUDING STRUCTRUAL MEMBERS, THAT CONSTITUTE A UNIT POWER SOURCE.

• A COMPLEX OF STRUCTURE, MACHINERY & ASSOCIATED EQUP FOR GENERATING ELECTRICAL ENERGY FROM ANOTHER SOURCE OF ENERGY

• ENERGY CENTRES OR SALABLE ENERGY• HIGH GRADE AND LOW GRADE ENERGY• DEGRADATION OF ENERGY--?SURROUNDING BEING HEATED---

IMPORTANT TERMS

• RENEWABLE RESOURCES—INFINITE RESOUCES• NON RENEWABLE RESOURCES- usually finite• CLASSIFICATION OF PP- BY FUEL, BY PRIME MOVER, BY

DUTY • CONVENTIONAL & NON CONVENTIONAL POWER

STATIONS• ENERGY DENSITY—COAL & SOLAR COMPARISION• ENERGY CONVERTORS-ELECTRIC MOTOR• ENERGY CONSUMPTIONS-PAKISTAN.• HUILE BLANCHE

SOURCES OF FUEL

• WATER-3 GORGES DAM, 22,500MW• COAL- 5780 MW• FUEL OIL -4,400 MW• PEAT- 1500 MW• BIOFUEL- 750 MW• GEO THERMAL- 303 MW• PUMPED STORAGE HYDROELECTRICITY(PSH)-

3,000MW

FUEL SOURCES

• RUN OF THE RIVER---2,620 MW• TIDE—254 MW• SOLAR POWER –80.7MW• CONCENTRATED PHOTOVOLTIC---37 MW• WAVE—ONSHORE & OFFSHORE• PL FIND ENERGY MIX OF PAKISTAN , PROJECTS

IN PIPE LINE ?

OIL SHALE

• ALSO CALLED KEROGEN SHALE.

• ORGANIC RICH FINE GRAINED SEDEMENTARY ROCKED

• PYROLYSIS YIELDS VAPOUR .UPON COOLING IT CAN BE USED AS LOW GRADE OIL

• ESTIMATES OF 2.8 TO 3.3 TRILLION BARRELS OF OIL

METHANE HYDRATE/ICE

• METHANE CHATHRATE FOUND IN LOW TEMP REGIONS-ITS IS ENVISIONED AS A GAME CHANGER

• WATER MOLECULE SURROUNDS METHANE

• CRYSTALLINE SOLID CONSISTS OF METHANE MOLECULES SURROUNDED BY A CAGE OF INTERLOCKING WATER MOLECULES.

LAYOUT OF PP

CLASSIFICATION OF POWER PLANTS

THERMODYNAMIC ANALYSIS

• SENSIBLE HEAT– TEMP CHANGE• LATENT HEAT ---PHYSICAL STATE OF SUBSTANCE• WHEN HEAT IS NOT REFLECTED IN TEMP CHANGE,

WE INCREASE THE DISTANCE BETWEEN MOLECULES.

• SO LATENT HEAT IS THE ENERGY PRICE THAT MUST BE PAID FOR A CHANGE OF STATE.THE ENERGY IS NOT LOST COMPLETELY BUT STORED AS INTERNAL ENERGY AND IS REPAID WHEN IT AGAIN CHANGES ITS STATE.

GENERATION OF STEAM

• PROCESS OF BOILING-LIQUID AND VAPOUR EQUILIBRIUM AND IT DEPENDS ON PRESSURE

• WHEN A LIQUID IS BOILING AND GENERATING VAPOUR IT IS SATURATED LIQUID AND SARURATED VAPOUR.SATURATION TEMP AND SATURATION PRESSURE

• CRITICAL POINT –UNIQUE WORKING FLUID.

• BOILER OPERATES AT CONSTANT PRESSURE

• FURTHER HEAT IS ADDED IN SUPER HEATER AND IS SUPER HEATED STEAM.

• THE AMOUNT BY WHICH THE TEMP OF SUPERHEATER STEAM EXCEEDS THE TEMP OF SATURATED STEAM AT THE SAME PRESSURE IS DEGREE OF SUPERHEAT.( 790-490)= 300 AT 600PSI

SUPERHEATING

• SUPERHEATING PROVIDES A GREATER TEMP DIFFERENCE BETWEEN BOILER AND CONDENSOR THUS ALLOWING MORE HEAT TO BE CONVERTED TO WORK AT THE TURBINES.

• SUPERHEAT STEAM IS DRY AND CAUSES LESS CORROSION OF PIPING AND MACHINERY.

• DOES NOT CONDUCT HEAT AS RAPIDLY AS SATURATED STEAM.

• INCREASED EFFICIENCY WHICH RESULTS FROM THE USE OF SUPERHEATED STEAM REDUCES THE AMOUNT OF FUEL OIL REQUIRED TO GENERATE EACH KG OF STEAM, HENCE WEIGHT AND SPACE REQUIREMENT

STEAM TABLES

ENERGY ANALYSIS

NUMERICAL

• A RIGID TANK CONTAINS 50 KG OF SATURATED LIQUID WATER AT 90 °C. DETERMINE THE PRESSURE IN THE TANK AND THE VOLUME OF THE TANK?

• A RIGID TANK CONTAINS 10 KG OF WATER AT 90°C. IF 8 KG OF THE WATER IS IN LIQUID FORM AND THE RESTIS IN THE FORM OF VAPOUR. FIND PRESSURE AND VOLUME?