The Moscow company "Fast Engineering" has developed a continuous gas generator with a separate pre-drying chamber, which was installed in front of the main heated channels. The solution should reduce the size of the unit and more efficiently use heat; the documentation was published in the FIPS database.

Crushed solid fuel first enters the drying chamber. Flue gas with a temperature of 200–300 °C, which exits the outer jacket of the working channels, is directed there. Through direct contact, the flow transfers heat to the fuel and carries away evaporating water from the chamber. After drying, the material enters the main channels already heated to 150–200 °C.

In the previous scheme, a significant part of the working channels was actually used for preheating and moisture removal. For some types of raw materials, the water content can reach 50% of the mass, so a large heat transfer surface was required for drying.

The new chamber moves preliminary drying outside the main gasification zone. Moreover, the existing heat carrier is used — no additional energy source is needed for this stage.

According to the developers' calculations, this solution significantly shortens the length of the heated channels, thereby reducing the mass and size parameters of the entire gas generator.

Earlier in Russia, a gas generator design for a ramjet engine was also developed, which ensures uniform mixing of fuel with air throughout the entire cross-section of the combustion chamber.