Download - 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*
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
H.C.T.M. KAITHAL
GAURAV SHARMA*
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
H.C.T.M. KAITHAL
JITENDER KUMAR*
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
H.C.T.M. KAITHAL
BHANU PARTAP SINGH*
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
H.C.T.M. KAITHAL
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