Combustion Engine Design and Operation Using Coal Dust as Fuel—Historical Overview

These processes were developed in their assumptions both for the purposes of hydrogenation of coal for liquid fuels and direct use of extracts for motor propulsion (which was obviously cheaper than supplying them with liquid fuel). There was also a third important application - obtaining electrode coke, which at that time was a strategic raw material.

As for the rotational speed - the Lenoir engine, the first commercial combustion engine operating at atmospheric pressure (without compression of the load), reached 400 rpm with difficulty in its first releases (then even 600). The combustion speed strongly depends on the pressure. The coal extract was fed with Deutza diesel (which could also work on diesel oil and oil) and there were no major differences, at higher loads the power on the extract was even higher.

As we are already at Lenoir, it is worth mentioning here that, as it seems first, he began to construct engines powered directly by a gasifier, both for vehicles and for boats, from the early 1880s.

And when we talk about the French, it's impossible not to write about Niepcem. Yes, yes - the same with Nicephora Niepce, who invented the photograph. Well, he was simultaneously, together with his brother Claud, the inventor of the pyrelophore - a dust engine. And it happened in 1807 in Chalon nad Saôme where the brothers demonstrated before the special commission a boat powered by such a motor. A boat with a displacement of 900 kg moved briskly against the Saony current, consuming 8 grams of fuel per minute. Here is a curiosity - this fuel was spores lycopodium, that is to our fork (formerly commonly used in medicine and crafts).

igord wrote:

karaluch84 wrote:

In addition, to gasify the coal you need to provide a lot of energy - a significant part of the coal poured into the generator will simply burn in it ...

In fact, coal gasification technology does not need ANY energy from outside. Simply HOLDING any carbon containing mass mainly into CO and H2. And that during this process it takes place and burning completely and burning to soot is another matter.

I think I've been misunderstood. My point was that when coal is burned to CO, thermal energy is released, which is lost. Through the walls of the generator it escapes into the environment, and the gas - before it is cleaned and sucked into the cylinder - also cools down along the way, transferring heat to the installations through which it passes. Combustion of CO to CO2 provides more energy than C to CO, but less than burning carbon directly to CO2.

In the case of gasification, we do not burn coal according to 2C + O2 -> 2CO, and C + H2O -> CO + H2 - so energy
obtained from combining carbon with oxygen is used to separate hydrogen and oxygen from water, and loses less.
More specifically, both reactions are used for change, because the first one gives heat, the other absorbs it.
A heat exchanger could be used to heat the water (and its a few more) at the expense of heat from the "exhaust".
Tołłoczko in the book Inorganic chemistry states that gasification in this way has an efficiency of 98%.

It is possible to use the fact that the coal dust is explosive after the formation of the mixture with air. The speed of the shockwave can be several kilometers per second. The main problem would be to create a homogeneous mixture in the cylinder and just feed it into the combustion chamber.

Underclocker wrote:

The main problem would be to create a homogeneous mixture in the cylinder and just apply it to the combustion chamber.

I wonder if it would be practical to create a mixture in a small tank located near the head? If you assume that this tank would be equipped with a stirrer constantly creating air turbulence and dust (probably some aerodynamics and fluid mechanics would give you the right shape and size of the tank and agitator), it could be enough to install something like a small throttle, regulating the amount of mixture getting into the intake duct (when the throttle was completely closed, the engine would suck in only air) during the intake stroke? It could work satisfactorily, or not? Or maybe someone has invented something like that or even patented it?

If you think about keeping the mixture of coal dust and air constant, it would be a difficult matter. Such a suspension is highly explosive, you need to use non-electrifying materials and ensure the right temperature in the mixing chamber. After that, coal dust in mining conditions is considered dangerous or explosive if the content of volatile matter is 10% or more. Most Polish mines would provide us with such fuel.