Abstract: A system is provided for cooling high-temperature, high-pressure gasifiers having cooling tubes which extend vertically through the walls of the gasifier and are connected in a closed cooling water circulation system.In accordance with the invention, the cooling tubes are coated on the inside of the gasifier with a plasma or flame sprayed ceramic coating, preferably consisting of alumina, and are embedded in a ramming compound such as tamped clay.

Abstract: A system for cooling high-temperature gasifiers and method for its operation wherein cooling conduits extend vertically through the walls of the gasifier and are connected at their ends to a closed-water circulation system which incorporates heat exchangers for removing heat from the system. Boiling in the system is prevented, and good heat transfer characteristics are achieved, by maintaining a high pressure system, at least 40 bar, coupled with a flow velocity of between 5 and 7 meters per second at a maximum internal diameter of the cooling conduits of 51 millimeters. Means are provided for maintaining the temperature of the water exiting from the cooling conduits at least 10.degree. C below the boiling point at the pressure and flow rate of the system.