Magneto Hydro Dynamic Power Generation

COMBINED WORKING OF MAGNETO HYDRO DYNAMIC POWER GENERATOR WITH THERMAL POWER PLANT

NITIN AGGARWAL**

DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

H.C.T.M. KAITHAL

RAVI SHARMA*


H.C.T.M. KAITHAL

[email protected]

GAURAV SHARMA*


H.C.T.M. KAITHAL

JITENDER KUMAR*


H.C.T.M. KAITHAL

[email protected]

BHANU PARTAP SINGH*


H.C.T.M. KAITHAL

[email protected]

mailto:[email protected]



ABSTRACT

MHD power generation is a new system of electrical power generation which is said to be of high efficiency and low pollution .In advanced countries MHD generation are widely used but in developing countries is still under construction. Efficiency matters the most for establishing a power plant, the MHD power plant have an overall efficiency of 55-60%. But a thermal power plant have an efficiency of only 35% means the

power generation by a thermal power plant is not efficient. However, the efficiency of this plant can be increased by combining this power plant with MHD power plant. by combining these two we will obtain an overall efficiency of 50%.

1. INTRODUCTION The Magneto Hydrodynamic power generation technology (MHD ) is the production of electrical power utilizing a high temperature conducting plasma moving through an intense magnetic field. The conversion process in MHD was initially described by Michael Faraday in 1893. Electric energy occupies top grade in the energy hierarchy. It finds innumerable use in the home, industries, agriculture and even in transport. The fact that electricity can be transported practically instantaneously is almost pollution frees at the consumer

level and that its use can be controlled very easily make it very attractive as compared to form of energy. The per capita consumption of electricity in any country is an index of the standard of living of the people in that country.

2 PRICIPLE OF MHD POWER GENERATION

The principle of MHD generation is simply that discovered by faraday: when an electric conductor moves across a magnetic field, a is induced in it which produces an electric current. This is the principle of conventional generator also, where the conductor consist of copper strips. In MHD generator, the solid conductors are replace by a gaseous conductor ; an ionized gas. If such a gas is passed at a high velocity through a power full magnetic field, a current is generated and extracted by placing electrodes in a suitable position in the stream. This arrangement as illustrated in fig. provide dc power directly. [5]The principle can be explained follows an electric conductor moving through a magnetic field experiences a retarding force as well as an induced electric field and current. This effect is a result faraday’s law of electromagnetic induction. he induced E.M.F is given by Eind = µ×BWhere u is the velocity of the conductor and B is the magnetic field intensity as shown in fig. the induced current density is Jind = σ

The Lorentz Force Law describes the effects of a charged particle moving in a constant magnetic field. The simplest form of this law is given by the vector equation.

Fig.1 Principle of MHD Generator[1]

PRINCIPAL OF MHD POWER

GENERATION

Jind = σ

The Lorentz Force Law describes the effects of a charged particle moving in a constant magnetic field. The simplest form of this law is given by the vector equation.

F= Q. (v×B)

Where The vector F is the force acting

on the particle,

Q is charge of particle,

v is velocity of particle,

B is magnetic field.

F is perpendicular to both v and B

according to the Right hand rule. Where

u is the velocity of the conductor and B

is the magnetic field intensity.

Magneto means magnetic field

Hydro means liquid

Dynamic means movements

3 Combine mhd &steam plantin a MHD generator it is not a solid

metal conductor but a gaseous

conductor-in fact a high temperature

ionized gas-that passes across the

magnetic field created by a powerful

magnet. the combustion products of

coal as the working fluid, the electrical

conductivity of which is enhanced by the

addition of potassium carbonate “seed”.

A typical coal-fired, commercially

viable MHD generator converts about 20

per cent of the thermal input power to

direct current electricity. Hence, at the

exit of the generator most of the thermal

energy is still in the gas but it is no

longer usable for MHD power

production due to its low electrica.l

conductivity. The combined MHD/steam

cycle, shown in Figure I, is

thermodynamically in series and

electrically in parallel. It has a potential

for converting up to 50 per cent of the

coal's energy in to electricity, compared

with 35 to 40 per cent for a conventional

power plant. In addition the MHD

generator removes most of the sulphur

from the effluent due to a

sulphur/potassium reaction inherent in

the process, while at the same time

nitrogen oxides are reduced to a level.

Fig. schematic diagram combination of

mhd and steam plant

A typical commercially viable coal-fired

MHD generator, shown schematically in

Figure 5, may be 10 to 20 metres long,

with a I m2 flow cross-section and will

have hundreds of pairs of current

collecting electrodes. The generator

walls are subjected to a heat flux

reaching 400 W/cm2 to

corrosion/erosion resulting from the hot

(2500 K) high speed

(1000m/s) slag, sulphur and potassium

laden gas flow, and also to electric fields

that locally reach 10 kV/m. About 50 per

cent of the internal surface of the

generator is formed by electrodes.

Coal combustion was simulated by

injecting fly ash and sulphur dioxide into

the oil-fired combustor, the weight

fraction of sulphur being 0.18 per cent of

the total mass flow. The generator is one

metre long and has 56 pairs of

electrodes.

Hall (axial) electric field and electrical

power density as a function of electrode

number.

Conclusion

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Magneto Hydro Dynamic Power Generation