MHD generator in the chimney of the furnace to generate free electricity

An article that appeared thanks to a comment from a reader:

We are talking about the technology of generating electricity by a magnetohydrodynamic generator. I had read about it briefly earlier, but I thought it was a complex technology, although this principle of generating electricity has long been known:

Brief description of the principle: the flow of ionized matter (plasma, for example), passing through a magnetic field in which the charges are separated, are deflected by the Lorentz force. They collide with the electrode plates. A potential difference appears on the plates. When the plates are connected to a closed circuit, a constant electric current appears.

Voltage and current strength depends on the degree of ionization of the flow, the strength of the magnetic field (the degree of deflection of ions and electrons) and on the speed of the flow of matter. All these indicators need to be maximized in order to obtain the possibility of obtaining large power capacities. An example of an attempt at industrial use of the magnetohydrodynamic effect:

In the Ryazan region in Novomichurinsk in the 80s. a power plant with an MHD generator was under construction. But the unit was never put into operation. The power plant was refurbished in 2010. and made of it a classic CHPP as part of the Ryazan State District Power Plant.

So, the planned generation capacity of the MHD installation at this station in Novomichurinsk is 500 MW. The second stage was provided for a gas turbine power 300 MW. 800 MW - and this is just one block! The efficiency of such a pair is up to 65%. The reasons for the phasing out of this technology are unknown. One can only guess about them.

There are photographs of experimental installations of MHD generators of the Institute of High Temperatures of the USSR Academy of Sciences. There, research has been conducted since the 60s.

Another interesting fact:

In the 70s there was the Khibiny project - an experiment of geophysical electrical sounding of the earth's crust. A pulsed MHD generator with maximum power was used there. 100 MW, current strength 20 CA and an operating time of about 10 s.

What exists in an industrial version can almost always be implemented in a domestic version according to a simplified scheme. So did the reader who left the comment. Physics in its setup:

When wood burns, a low-temperature plasma is formed. But the degree of its ionization is low. The concentration of ions is strongly dependent on potassium compounds (potash, which was previously obtained from wood ash). And the rate of rise of gases in the pipe is not high. But if you put several mini MHD installations on neodymium magnets in series, then, as you can see, you can get real indicators of current and voltage.

The design is quite simple, the main cost is magnets. This is not an "Indigirka" oven with a generator on Peltier elements for $ 75,000. rub.!

The schematic design looks like in this figure of the laboratory model of the MHD generator.

Only in this installation (as can be seen from the reader's comment), there is a problem - this is the cooling of the magnets. Magnetic substances have a so-called Curie point - the temperature at which they lose their magnetic properties. Magnets need to be cooled, water cooling needs to be supplied.

This is solvable. They are placed in a water jacket of a container connected to a 20-30 l water tank. When heated, water in the system will circulate by itself (by convection). When the stove is heated, 50 liters of water in the tank in my bathhouse only boils after 3-4 hours.

It is better to use an electromagnet, but due to the low efficiency of the installation in the chimney, it will eat up most of the generating electricity. And the electrodes in the chimney must be fire resistant.

In general, this article describes only the idea, but at the initial stage it was possible to translate it into a stove-stove. Having solved the issue of cooling the magnets, the generator will be durable. The use of a household installation is areas without electricity, hunter's houses and as a backup lighting system when a stove or boiler with a steel chimney is heated.

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Photo taken from open sources, from Yandex. Pictures

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