What is anaerobic combustion?

Answer 1

Anaerobic reactions are such reactions that do not require air in order to occur. Anaerobic combustion would be something burning without ambient oxygen. Traditional examples are sealed septic systems where bacteria digests biowaste products and, also, wet hay spontaneously combusts, even fermenting wine releases heat anaerobically.

Anaerobic combustion was developed by Nazi Germany during World War Two to propel U-Boat submarines with limited success. Applications of anaerobic combustion before and after that event are obscure. Competing solutions to oxygenize fuel for more complete combustion of fossil fuels are prolific. Nitrous Oxide is one chemical to increase performance of sports cars by diluting the 70% Nitrogen component of ambient air without the use of turbochargers or superchargers to increase manifold pressure.

"Anaerobic combustion" as a term is slightly deceiving in that it is used to describe a combustion process, typically 4-cycle engines, that are not aspirated by Earth's atmosphere to accomplish combustion. Mostly, all combustion processes rely on the presence of oxygen with fuel exposed to an ignition device to perform combustion inside Internal Combustion Engines (ICE).

Improving technology has made possible ICEs that have a closed loop fuel system sealed away from its environment. Oxygen and fuel(s) are regenerated from combustion products (exhaust gases) and re-entered into the intake manifold. Presently, regeneration requires a large tank to hold hot expanded combustion gases and engine output is decreased.

Oxygen infused fossil fuels are a consideration to improve anaerobic combustion but presently, market forces eschew the added expense and hazard of higher volatility.