gas turbines direct injection engines fixed bed combustors

2. Class MS Energy Engineering
Course: Advance clean coal
Technology CHE-636
Prof. Dr Suleman Tahir

3. Topic
Gas Turbines
Direct Injection Engines
Fluidized -bed combustors

4. Gas Turbines
WHAT IS A GAS TURBINE ?
The Gas turbine is the engine at the heart of the
power plant that produces electric current.
A Gas turbine also called a combustion turbine.
It is a type of continuous combustion, internal
combustion engine.

5. Gas turbine
• A gas turbine also called combustion turbine, is type of internal
combustion (I.C) Engine. It has an upstream rotating compressor coupled
to a downstream turbine, and a combustion chamber in between.
Gas Turbine and its components

6. OREREATION OF GAS
TURBINE
• Energy is added to the gas stream in combustor, where fuel is
mixed to the air and ignited.in the high pressure environment
of the combustor, combustion of the fuel is increased the
temperature. The product of the combustion are forced in to
the turbine section. There, a high velocity and volume of the
gas flow is directed to through a nozzle over a turbine blades,
spinning the turbine which power the compressor and, for
some turbines, drive their mechanical output. The energy
given up to the turbine come from the reduction in the
temperature and pressure of the exhaust gas.

7. Main parts
There are three main parts of gas turbine.
1. An upstream rotating gas compressor.
2. A combustor.
3. A downstream turbine on the same shaft as
the compressor

8. Air compressor
• The air compressor and turbine are mounted at either
end on common shaft, with the combustion chamber
between them.
• Gas turbines are not self starting a starting motor is
used.
• The air compressor suck the air and compresses it,
thereby increasing its temperature and pressure.

9. Combustion chamber
• In the combustion chamber the compressed air is
mixed with fuel, and the resulting mixture is burned.
• The greater pressure of air, the fuel mixture will burn
better.
• Modern gas turbines usually used liquid fuels, but
they may also use gaseous fuel, natural gas or gas
produced artificially by gasification of solid fuels.

10. Turbine
• Hot gasses move through a multistage gas turbine.
• Like in steam turbine, the gas turbine also has moving
and stationary blades.
• The stationary blades.
i. Guide the moving gases to the rotor blades.
ii. Adjust its velocity
• The shaft of the turbine is coupled to the generator.

13. Working
• A gas turbine is a combustion engine that can
convert natural gas or other liquid fuels to
mechanical energy.
• This energy then drives a generator that
produces electrical energy.
• It is electrical energy that moves along power
lines to homes and businesses.

14. Working process

15. The gas turbine compresses air and mixes it with fuel
that is then burned at extremely high temperatures,
creating a hot gas.
The gas turbine heats a mixture of air and fuel at very
high temperatures, causing the turbine blades to spin.
The hot air-and-fuel mixture moves through blades in
the turbine, causing them to spin quickly.
Spinning blades turn the drive shaft.
The fast-spinning turbine blades rotate the turbine
drive shaft. The spinning turbine is connected to the
rod in a generator that turns a large magnet
surrounded by coils of copper wire.

16. The spinning turbine is connected to the rod in a
generator that turns a large magnet surrounded
by coils of copper wire.
The gas turbine can be used in combination with
a steam turbine in a combined-cycle power plant
to create power extremely efficiently.
The GE 7F.05 gas turbine generates 225 MW,
equivalent to 644,000 horsepower, or the power
of 644 Formula One cars.

17. Cycle of gas turbine
Open cycle working gas turbine

19. Advantages of gas turbine.
• Storage of fuel required less area and handling is easy.
• The cost of maintenance is less.
• It is simple construction there is no need of boiler,
condenser and other accessories as in the case of
steam power plant.
• Cheaper fuel used such as kerosene, paraffin, benzene
and powdered coal.
• Less pollution and less water is required.

20. Direct Injection Engines
What is Direct Injection?

21. Diesel Direct Injection (DI) is a basic type of
fuel injection system which many earlier
generation diesel engines used

22. The simple DI diesel engines inject the fuel into
the combustion chamber above the piston
directly.
The compression of air inside the combustion
chamber raises its temperature above 400oC.
Then it ignites the diesel fuel injected into the
combustion chamber. Hence the diesel engines
are also known as Compression Ignition engines.

23. Direct injection has been used on diesel engines
since the 1950s.
These systems use a powerful, positive
displacement fuel pump to pump diesel through
injectors mounted directly in the cylinder.

24. These injectors sit about where the spark plug
would be on a gas engine and work well with
diesel engines because they can introduce huge
amounts of fuel into the combustion chamber
just as the piston reaches its peak compression.

25. This makes the combustion event much faster.
Quieter and more powerful. One interesting
component that sets direct injection apart from
other types is the fuel pump. A direct injection
pump is almost identical in form and function
to a tiny four-stroke engine, but passes liquid
diesel fuel instead of air and fuel.

26. Fluidized -Bed Combustors
What is combustor ..?
A combustor is a component or area of a gas
turbine, ramjet, or scramjet engine where
combustion takes place.
Or
Fluidized bed combustion (FBC) is a combustion
technology used to burn solid fuels.

27. Biomass combustion technologies burn a variety
of biomass fuels, including wood, crop remnants,
wood pulp and chips, and municipal solid waste.
These materials are difficult to burn efficiently
in conventional furnaces because of several
inherent properties, including overall low heating
value, low fixed carbon, and higher moisture
content.

28. In its most basic form, fluidity bed of ash and
other particulate mat fuel particles are suspended
in a hot, bubbling aerials (sand, limestone etc.)
through which jets of air are blown to provide
the oxygen required for combustion or
gasification.
Resultant fast and intimate mixing of gas and
solids promotes rapid heat transfer and chemical
reactions within the bed. FBC plants are capable
of burning a variety of low-grade solid fuels,
including most types of coal and woody

29. Fluidized Bed combustor

30. Two Types of Fluidized bed
Bubbling fluidized bed (BFB)
Circulating fluidized bed (CFB)

31. Bubbling fluidized bed (BFB)
In BFB boilers the velocity of the combustion air
is low enough that the fluidized particles remain
in the lower furnace.

32. The fuel is in contact with the particles and
effective mixing and combustion allows good
efficiency and low emissions.
Typically 97% to 99% of all burnable carbon in
the fuel stream is combusted, even hard-to-burn
materials.
Boiler thermal efficiencies can be as high as 87%
or more.

34. Working
The bubbling fluidized-bed (BFB) gasifier is shown
in Figure in which the gasification agent is injected
from the gasifier bottom and the producer gas exits
from the gasifier top while the solid fuel is
introduced to the bed.
This type of gasifier is characterized by the
bubbling of bed material and solid fuel by flowing
gas through it when the gas velocity is sufficiently
high..

35. The bed material can be an inert medium such as
sand or catalytic material such as Ca O
The fluidization of the solid fuel and the bed
material enhances heat and mass transfer
between the solids and the gases, thus promoting
the gasification reactions and maintaining target
operation temperature.

36. Circulating fluidized bed (CFB)
Circulating fluidized bed is a relatively new
technology with the ability to achieve lower
emission of pollutants.
Circulating fluidized bed (CFB) boilers from
Mitsubishi Hitachi Power Systems (MHPS) are able
to combust a wide range of fuels, including
bituminous coal, brown coal, anthracite, petroleum
coke, wood biomass, paper sludge, RPF (refuse
paper & plastic fuel) and waste tires, and have high
combustion efficiency.
.

37. Working
In a CFB unit the velocity is greater and hot
particles are circulated through the entire range
of the boiler combustion zone.
CFB systems are effective with biofuels, CFB is
especially suitable for large boiler load ranges.
CFB technology provides fuel flexibility in that
it can burn wood and high Btu fuel.

39. Working
As for temperatures inside the furnace, while a
regular boiler reaches 1,400-1,500°C,
temperatures inside a CFB are in the low range
of 800-900°C, thus inhibiting the generation of
thermal nitrogen oxides (NOx whose production
is dependent on combustion temperature)

40. Applications
One of the applications of a circulating fluidized
bed scrubber is at power stations which utilize a
dry sorbent usually CA(OH)2 to reduce
pollutants like HF, HCL, SO2 and SO3 in a flue
gas stream.[8] Currently, Basin Electric Power
Cooperative are the only company operating the
best available circulating fluidized bed scrubbing
technology