Highly Disruptive Technology

MHD Superconducting Generators

MHD System Aspects

A magnetohydrodynamic (MHD) electric power generator directly converts the enthalpy of a gas into electrical energy using (non-equilibrium or equilibrium) plasma. This process is based on Faraday’s law of electromagnetic induction where, instead of an armature coil rotating in a magnetic field as in a conventional rotating generator, MHD uses an electrically conductive fluid moving through a magnetic field. The power generation in MHD is a conversion process – the electric power is extracted in an MHD generator because the Lorentz force of the output current and applied magnetic field acts to decelerate the working plasma and the working plasma loses its enthalpy which is converted into electrical power.

Intrinsic Technical Advantages

The field of MHD was initiated by Hannes Alfvén, for which he received the Nobel Prize in Physics in 1970.

3 Definitions of MHD: MHD generator converts mechanical energy of the fluid directly into electric energy.

1). MHD is in the field of Plasma Physics that deals with the study of the dynamics of an electrically conducting fluid in the presence of a magnetic field. A MHD generator is a device that produces electrical energy from an electrically conducting gas/plasma flowing through a transverse magnetic field.

2). Magnetohydrodynamics (MHD), or magnetofluiddynamics, is the academic discipline, which studies the dynamics of electrically-conducting fluids. It is the study of the motions of electrically conducting fluids and their interactions with magnetic fields. Examples of such fluids include plasmas and liquid metals. The set of equations, which describe MHD, is a combination of the Navier-Stokes equations of fluid dynamics and Maxwell's equations of electromagnetism.

3). Magnetohydrodynamic (MHD) generator - Plasma moving with velocity (more than the speed of sound) - perpendicular to a magnetic field - generates an electromotive force - perpendicular to both the direction of plasma flow and the magnetic field. This dynamo effect can drive a current in an external circuit connected to electrodes in the plasma, producing electric power without the inefficiency of a thermal cycle.

In a MHD generator, the solid conductors are replaced by a gaseous conductor, an ionized gas. If such a gas is passed at a high velocity through a powerful magnetic field, a current is generated and can be extracted by placing electrodes in suitable position in the stream.

MHD Efficiency:

Parameters of plasma such as temperature, pressure, velocity and electrical conductance, as well as on the induction of magnetic field in which it moves all effect MHD efficiency.

There are six factors that affect the electrical efficiency of the MHD system they are:

(1) Temperature, the electrical conductivity of the plasma increase greatly as temperature increases. Ionized by hot combustion gases. The super-hot plasmas are than in a State of Excitation which makes it give off an electrical current when passing through a magnetic field. The high temperature creates lose electrons that gives off electricity to the electrodes in the MHD channel.

A plasma is typically an ionized gas. Plasma is considered to be a distinct state of matter, apart from gases, because of its unique properties. Ionized refers to presence of one or more free electrons, which are not bound to an atom or molecule. The free electric charges make the plasma electrically conductive so that it responds strongly to magnetic fields.

(2) Intensity of plasma flow: Optimum pressure of plasma and velocity. Speed of the plasma through a nozzle designed to discharge plasma at an exit, supersonic flow Mach number. The faster the speed of the plasma the more electricity is generated when passing through the MHD channel. The working fluid is introduced into the MHD generator through a nozzle. Constant Mach's number along the MHD channel are best.

(3) Type of ionazable mixture used as a working fluid. Ionization is a process in which electrons are removed from an Atom. Alkali vapor metals will be used. Such as Potassium Carbonate, Lithium, Sodium and Cesium. Which are seeded into an inert Gas - convenient carrier such as Helium, Argon, Neon, or Xenon, or a mixture thereof. The liquid metal provides the electrical conductivity. Conduction is due to the free electrons and positive ions which move under the effect of a magnetic field.

(4) Applied magnetic field strength, the greater the strength the higher the electrical output, a strong magnetic field of 4-17 tesla.

(5) Type of Electrode used in MHD channel. Electroceramics, Tungsten molybdenum-superalloys, lends itself to use as an electrode material. Electrodes in the MHD generator perform the same function as brushes in a conventional DC generator. Flush-mounted transversely segmented electrodes set in uniform distribution of current density along the Faraday MHD channel, ensuring a full utilization of the channel volume.

(6) MHD Channel Geometry

Historical comment:

The principles of MHD have been known since the studies of Michael Faraday in the 1830's. However, the first attempts to construct a large MHD generator, made in 1938, were unsuccessful due to poor knowledge of the plasma properties. By 1959 the understanding and the technology progressed to the point that 10 kW of electric power was generated in an MHD device.

"The technology is a mouthful—Magnetohydrodynamics, or MHD—but the concept is simple. Concentrate the rays of the sun by mirrors or lens to create superheated gas and then use superconducting magnets to extract electricity from this gas. Think of the system as an electrical generator where wires are replaced by ionized gas." - Forbes

Wires are solid conductors and ionized gases are liquid conductors.

"Superconducting wires have been known to carry electricity for years with no measurable loss" - National Geographic

"We're applying superconducting magnets to make lower-cost systems” - Keith Longton GE

Magnetohydrodynamic (MHD) conversion processes offer a highly efficient, clean and direct conversion of energy for power generation and propulsion.

Solar/Gas/Biodiesel MHD power generation innovation has the potential to launch an entirely new electric power generation. CSPU Magnetohydrodynamic topping cycle generator creates higher efficiency for existing power plants. Even a small energy savings could make a big difference. MHD topping cycle generators will reduce the cost of electricity, improving the overall efficiencies of the system.

A Quantum Leap Over Existing Technologies In Efficiency

The Direct Conversion of Kinetic Energy of a Flowing Fluid into Electricity

The MHD Generator Can be Considered to be a Fluid Dynamo

"MHD (magnetohydrodynamics) power generation systems are expected to become popular with the development of superconducting technology because of their low cost and high efficiency". - HARVARD-SMITHSONIAN CENTER FOR ASTROPHYSICS

A Major Advancement To The Power Industry
Convert Kinetic Energy of An Energetic Fluid Into Electric Energy

The flow (motion) of the conducting plasma through a magnetic field causes a voltage to be generated (and an associated current to flow) across the plasma, perpendicular to both the plasma flow and the magnetic field according to Fleming's Right Hand Rule.

Magnetohydrodynamic (MHD) power plants offer the potential for large-scale electrical power generation with reduced impact on the environment.

Power Plants with Magnetohydrodynamic Topping Cycle

CSPU MHD generators can maximize the energy benefits of both new and existing power plants, by increasing their power output capacity and overall system efficiency.

This is done by using a MHD “topping cycle,” which utilizes the incoming higher temperature heat before it enters conventional electrical generators. Solar, Geothermal and industrial waste heat can also be used.

Electromagnetic Turbine

In the 1970´s and 80´s MHD was pursued as technology that could improve the efficiency of coal-fired power plants.

MHD stand-alone units can convert energy into power more efficiently than other types of power system. The system will also be incorporating the stacking of heat engines to increase the overall efficiency. MHD is more efficient than power plants operating at comparable temperatures.

The MHD heat source may be combustion of a fuel, solar, geothermal, chemical reaction, or waste heat in the form of a hot gas.

"MHD process opens up a temperature regime beyond that of any other process. Within that regime, it stands alone, without a competitor and can provide a topping cycle for many of the competing cycles." - European Commission

Because MHD requires no moving parts, its maximum operating temperature can be much elevated higher compared to conventional electrical machines that rely on mechanical shaft power. Therefore, MHD generators are potentially much more efficient than conventional electricity generators. This is because the isentropic efficiency of a thermodynamic cycle is directly related to the differential temperature, i.e., the temperature of the hot (TH) and cold (TC) thermal reservoirs according to the Carnot efficiency:

In addition, the direct conversion of thermal energy to electrical energy eliminate the inefficiencies associated with thermal-to-mechanical and then mechanical-to-electrical energy conversion.


Historical Background The first idea of magnetohydrodynamic phenomenon was conceived by Michael Faraday in 1832, during his original investigation of electromagnetic induction. Early in the 20th century a large number of magnetohydrodynamic (MHD) devices and machines were invented and patented. In 1907 the first MHD pump was designed by Northrup. An MHD pump is a device which converts the electrical energy of the current supplied into mechanical energy of the pumped fluid. By inverting the operating principle of the MHD pump, an MHD generator was invented and patented by Karlovitz and Halacz in 1910.

In 1930 Williams published the results of the first laboratory studies of MHD flows in pipes and ducts. A very comprehensive theoretical study of this subject was carried out by Hartmann and Lazarus in 1936 and 1937. In the early 1940s a large and otherwise sophisticated Hall current type MHD generator was built by Westinghouse Electric Corp. which failed due to insufficient knowledge of the properties of the ionized gases. Plasma studies in the 1950s, created a sufficient databank of these properties.

AVCO Mark 6 U-25 channel R

In 1959, an experimental MHD generator was built at the Avco Everett Research Laboratory that produced 11.5 kw of power and obtained an appreciable pressure drop with the interaction between the gas and magnetic field. In the early sixties many MHD generators operating at higher power levels were reported. The subsequent development of the MHD generators was pursued on basically three lines of approach: firstly, rare gas MHD generators, which used cesium seeded and thermally heated rare gas to get sufficient conductivity; secondly, liquid metal MHD generators, which suffered the inherent drawback of low flow rates; thirdly, combustion gas MHD generators, which utilized combustion products produced after burning the conventional type fuels. The earlier research work was concentrated on using the MHD generators to replace the conventional turbines. MHD generators have higher efficiencies (85-90%).

Russia built and operated (until the mid-90´s) a 25 MW MHD power plant for utility electricity production near Moscow.

An Actual Working 10 MW Russian MHD Generator Using a Superconducting Magnet

"The size and scope of the Soviet MHD-power generation program far exceeds that of the United States. The USSR is now operating the world's first MHD power plant, currently attaining 5 MW(e) of a 25-MW(e) planned power output. The Soviet closed-cycle MHD program appears to be small and lags that of the United States; the Soviet open-cycle effort (rep- resenting about 80 percent of their visible MHD research) leads that of the United States, which is believed to be about five years away from the construction of a pilot plant of the Soviet type. The USSR has considerable experience in integrated plant operation than the United States, because of its early concentration on military applications. The USSR has a substantially advanced understanding of high-performance MHD-generator operation." - U. S. and Soviet MHD Technology: A Comparative Overview

Russian Magnetohydrodynamic U-25 GENERATOR

The U-25 MHD Generator in Moscow was (1975) the largest operating MHD device. The design output of the U-25 is 25 MW.

In the early 1970's the High Temperature Institute of the USSR Academy of Sciences constructed the first large MHD pilot facility, the U-25, which has successfully supplied electricity to the Moscow grid. The U-25 contains all the main components of future industrial power stations that will make use of an MHD generator.

The fuel selected for the U-25 facility is natural gas. Combustion takes place in oxygenenriched air that is preheated to 1200°C. To improve the conductivity of the plasma, use is made of a seed (alkaline metal) which is cycled to the combustor. The plasma flow, which has a temperature of over 2500°C, generates an electric current in the MHD generator channel inside the field of the electromagnet. Inverters convert the direct current from the' MHD generator into alternating current. The facility is controlled by a computer. After passing through the MHD generator, the plasma gives up its heat in a steam generator and the steam is used in the secondary circuit steam power plant. Before the heat-depleted plasma is discharged into the atmosphere, the seed is extracted and recycled to the combustor.

In the combustor of the U-25 facility, the thermal load in the flow chambei reaches 70 X 106 kcal/m3 .h, which is approximately 300 times higher than is achieved in the best modern steam boilers. The characteristic feature of the MHD generator combustor is that it operates under a very high potential — 5 kW in the U-25. Work is still going on to select the most suitable type of MHD generator channel for the U-25 device so as to ensure continuous channel operation over a prolonged period and at rated power. The principal design parameters for the U-25 have already been attained . The broad range of research performed with this facility has made it possible, even at the present stage, to begin construction of a pilot 500-MW MHD power station unit for industrial purposes. It should be pointed out that, for large-scale production, MHD power stations can operate under base-load, intermediate, or peak-load conditions.

Superconducting Magnet System for the 1MW MHD Power Generator
Institute of Electrical Engineers of Japan

Popular Science Magazine August 1978

Wikipedia - Magnetohydrodynamic Generator

Research and development is widely being done on MHD by different countries of the world. nations involved: - USA - Russia - Japan - India - China - Yugoslavia - Australia - Italy - Poland etc.

Superiority of MHD Power Generation
Superconducting Permanent Magnets
CSPU on BBC Radio
Concentrated Sunlight Heat Electricity - Solar MHD
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CSPU Intellectual Property Portfolio
CSPU Management
CSPU in Forbes
CSPU in the Press

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