geothermal.new

7/31/2019 Geothermal.new

1/50
http://geothermal.marin.org/GEOpresentation/sld004.htm


2/50


3/50

Thinned or fractured crust allows magma to rise to the surface

as lava. Most magma doesn't reach the surface but heats large

regions of underground rock


4/50


5/50

When the rising hot water and steam is trapped in permeable

and porous rocks under a layer of impermeable rock, it can

form a geothermal reservoir.


6/50


7/50

Exploration commonly begins with analysis of satellite

images and aerial photographs


8/50

,this volcano, Mt. Mayon in the Albay province of the

Philippines erupted in 1999.


9/50

structures are mapped in the region. This view

overlooks Basin and Range terrain East of the

Sierra Nevadas.


10/50


11/50


12/50


13/50


14/50


15/50


16/50


17/50


18/50

Th fi t d th l l t l b ilt i


19/50

The first modern geothermal power plants were also built in

Lardello, Italy. They were destroyed in World War II and rebuilt.

Today after 90 years, the Lardello field is still producing


20/50


21/50

GEOTHERMAL ENERGY

ENERGY FROM THE EARTHS OWN INTERIOR.

GEOTHERMAL ENERGY FROM THE EARTHS INTERIOR IS ALMOST INEXHAUSTIBLE AS SOLAR

OR WIND ENERGY.

CENTRE OF THE EARTH ESTIMATED AT TEMP UPTO 5,000K.

TOTAL ENERGY AVAILABLE TOWARDS EARTHS SURFACE-- 4.2x 10

10

KW.

GEOTHERMAL ENERGY CAN BE USED FOR HEAT AND POWER GENERATION.

ENERGY PRESENT AS HEAT WITH AVEARGE TEMP ABOUT 2000C AT A DEPTH OF 10 Km


22/50

(A) HOT MAGMA (MOLTEN ROCK)- PRESENT AT DEPTH >24 TO 40KM

(B) SOLID IGNEOUS ROCK(IGNEOUS MEANS FIRE -VOLCANIC ACTION

(c) POROUS & PERMEABLE RESERVOIR

(D) IMPERMEABLE SOLID ROCK(E) FISSURES

(F) GEYSERS FUMAROLS( STEAM IS CONTINOUSLY VENTED THROUGH FISSURES , THESE VENTS

ARE CALLED FUMAROLS)

(G) WELL

(H) HOT SPRING


23/50

HISTORY

FIRST APPLICATIONS OF GEOTHERMAL ENERGY WERE

SPACE HEATING, COOKING, MEDICINAL PURPOSES

FIRST ATTEMPT TO PRODUCE ELECTRICITY - LARDERELLO, ITALY IN 1904 WITH AN

ELECTRIC GENERATOR THAT POWERED FOUR LIGHT BULBS.

IN 1979, GLOBAL ELECTRICITY PRODUCTION FROM GEOTHERMAL RESOURCES

WAS 1872 MW

BY THE TURN OF THIS CENTURY GROW UPTO 1,00000 MW

ABOUT 340 KNOWN GEOTHERMAL AREAS IN INDIA

46 OF THESE SYSTEMS ARE OF HIGH TEMP ABOVE 1500C WHICH COULD

GENERATE 2000 MW FOR A PERIOD OF 30 YEARS

59 ARE INTERMEADIATE TEMP 900C TO 1500CCONSIDERED FOR POWER

GENERATION USING BINARY VAPOUR CYCLE.

PUGA VALLEY IN J&KHAVING 20MW

PARVATI VALLEY, MANIKARAN IN H.P


24/50

GEOTHERMAL FIELDS

Geothermal steam is of two kinds:

Magmetic steam- Steam originating fron magma itself

Meteoritic steam-Ground water is heated by magma

CLASSIFICATION OF EARTHS SURFACE

1. NON-THERMAL AREAS -- HAVING TEMP GRADIENT OF 1040 m/0C

2. SEMI THERMAL AREASHAVING TEMP. GRTADIENT OF 70 m/0C

3. HYPER THERMAL AREASHAVING TEMP.GRADIENT ABOVE 100 m/0C


25/50

Earth Temperature Gradient

http://www.geothermal.ch/eng/vision.html


26/50

TYPES OF GEOTHERMAL ENERGY

(GEOTHERMAL SOURCES)

GEOTHERMAL ENERGY RESERVOIRS ARE

LIQUID DOMINATED

STEAM DOMINATED

SOURCES ARE

1. HYDROTHERMAL SYSTEMS - HEATED BY HOT ROCKS, 2050C TO 3150C, 8 BAR

2. GEOPRESSURED SYSTEMS- HOT WATER AT 1600C, AT 2400 TO

9100M DEPTH, MORE THAN 1000 BAR

3. PETROTHERMAL SYSTEMS- HOT DRY ROCKS- AT 150 0C TO 2980C

NEAR THE EARTHS SURFACE85% OF GEOTHERMAL RESOURCES.


27/50

HYDROTHERMAL SYSTEMS

WATER IS HEATED BY HOT ROCKS

HEAT IS TRANSPORTED FROM THE HOT ROCKS BY CIRCULATING MOVEMENT( I.E. BY

CONVETION OF THE WATER IN A POROS MEDIUM)

TWO TYPES

1. VAPOUR DOMINATED

WATER IS VAPORISED INTO STEAM WHICH REACHES THE EARTHS SURFACE AT 8 BAR &

2050C.

STEAM CAN BE USED TO PRODUCE POWER BY RANKINE CYCLE WITH MINIMUM COSTS.

STEAM IS ASSOCATED WITH CORROSIVE & EROSIVE MATERIALS

2. LIQUID DOMINATED

HOT WATER IS TRAPPED UNDERGROUND AT A TEMP -1740C TO 3150C.

THIS WATER IS BROUGHT UP EITHER BY DRILLING WELLS OR PUMPED UP.


28/50


29/50

STEAM & WATER FROM HYDROTHERMAL SYSTEM CONTAIN THE FOLLOWING:

1. DISSOLVED SOLIDS IN WATER

2. ENTRAINED SOLID PARTICLES

3. NON-CONDENSABLE GASES ( C02, H2, N2 , NH3, H2S)

4. SAND

LARGE EXTRACTION OF GEOTHERMAL FLUIDS & REINJECTION INTO THE GROUND

POSE THE POSSSIBILITY OF SEISMIC DISTURBANCES.


30/50


31/50

VAPOR DOMINATED POWER PLANT

DRY STEAM AT 35 BAR , 2000

C IS AVAILABLE AT THE BOTTOM OF THE WELL. SUPERHEATED DUE TO PRESSURE DROP TO 7BAR

1-2 & 2-3THROTTLING PROCESS- ENTHALPY REMAINS CONSTANT

H2S REMAOVAL

REMOVED IN THE SHELLANDTUBE CONDENSER BY A PROCESS CALLEDSTRETFORD PROCESS- SULPHUR IS PRODUCED AS BY PRODUCT.

LOWEST COST

LEAST NO.OF SERIOUS PROBLEMS

Steam is used to drive a turbo-generator Steam is condensed and pumped back into the ground

A 55 MW plant requires 100 kg/s of steam


32/50

Dry Steam Schematic

Boyle, Renewable Energy, 2nd edition, 2004


33/50

LIQUID DOMONATED SYSTEMS(WET STEAM FIELDS)

INTHIS, WATER TEMPERATURE IS ABOVE THE NORMAL BOILING POINT, 1000C.

BUT WATER UNDER PRESSURE, IT DOES NOT BOILREMAINS IN LIQUID

WHEN WATER COMES TO THE SURFACE THE PRESSURE IS REDUCED, RAPID BOILING

THEN OCCURS AND LIQUID WATER FLASHES INTO A MIXTUREOF HOT WATER &STEAM.

STEAM IS SEPARATED AND USED IN TURBINE.

Two methods

A) Flashed-steam system ; suitable for water in the higher temp.

B) Binary cycle system suitable for water at moderate tem.

C) Total flow system; further development.


34/50

LIQUID DOMINATED (HIGH TEMERATURE) SYSTEM

EXAMPLE; VOLCANIC WAIRAKEI FIELD IN NEWZEALAND.

WATER IN HYDRO THERMAL RESERVOIR IS AT THE TEMERATURE ABOUT

230 0CPRESSURE OF 40 ATM( 4MPa)

DEPTHS OF 600 TO 1400 MFLASHED IN TOA MIXURE OF STEAM AND

WATER AT THE SURFACE.

PASSES THROUGH CYCLONE SEPARATOR TO REMOVE WATER. STEAM

SUPPLIED TO TURBINE.

l l h l


35/50

Single Flash Steam Power Plants

Steam with water extracted from ground

Pressure of mixture drops at surface and more water

flashes to steam

Steam separated from water

Steam drives a turbine

Turbine drives an electric generator

Generate between 5 and 100 MW Use 6 to 9 tonnes of steam per hour


36/50


37/50

Single Flash Steam Schematic



38/50


39/50

Double Flash Power Plants

Similar to single flash operation

Unflashed liquid flows to low-pressure tank

flashes to steam

Steam drives a second-stage turbine

Also uses exhaust from first turbine

Increases output 20-25% for 5% increase in

plant costs


40/50

Double Flash Schematic



41/50

Binary Cycle Power Plants

Low temps 100o and 150oC

Use heat to vaporize organic liquid

E.g., iso-butane, iso-pentane

Use vapor to drive turbine

Causes vapor to condense

Recycle continuously Typically 7 to 12 % efficient

0.1 40 MW units common

http://www.worldenergy.org/wec-geis/publications/reports/ser/geo/geo.asp


42/50


43/50

Binary Cycle Schematic



44/50

Binary Plant Power Output

http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm


45/50


46/50


47/50

Technology vs. TemperatureReservoir

Temperature

Reservoir

Fluid

Common

Use

Technology

commonly chosen

High Temperature

>220oC

(>430oF).

Water or

Steam

Power Generation

Direct Use

Flash Steam

Combined (Flash

and Binary) Cycle

Direct Fluid Use Heat Exchangers

Heat Pumps

Intermediate

Temperature

100-220oC

(212 - 390oF).

Water Power Generation

Direct Use Binary Cycle

Direct Fluid Use

Heat Exchangers Heat Pumps

Low Temperature

50-150oC

(120-300oF).

Water Direct Use

Direct Fluid Use

Heat Exchangers

http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm


48/50

Hot Dry Rock Technology

Fenton Hill planthttp://www.ees4.lanl.gov/hdr/


49/50

Hot Dry Rock Technology

Wells drilled 3-6 km into crust

Hot crystalline rock formations

Water pumped into formations

Water flows through natural fissures picking

up heat

Hot water/steam returns to surface

Steam used to generate power

http://www.ees4.lanl.gov/hdr/


50/50

Advantages of Geothermal

geothermal.new

Documents