Supercritical water gasification and recycling method and apparatus for steel mill high-oil-content iron-containing sludge

The invention relates to a supercritical water gasification and recycling method and apparatus for steel mill high-oil-content iron-containing sludge; steel mill high-oil-content iron-containing sludge is conditioned and then fed to and preheated in a heater using low-caloric blast furnace gas as a fuel, the preheated sludge is fed to a supercritical water gasification reactor and is subjected to supercritical water gasification before entering a gas-liquid separator, and separated mixed gas is separated to obtain high-caloric methane and hydrogen mixed gas; high-caloric fuel gas is produced by using low-caloric blast furnace gas and supercritical water gasification technique; after the iron-containing sludge is subjected to supercritical water gasification, iron matters therein are fully converted into ferriferous oxide; therefore, water-slag mixture separated from the gas-liquid separator can be simply dried and magnetically separated and then returned to a steel furnace as steelmaking material. The making