The present invention relates to a method for producing an oil-rich fraction (OF) from a primary feedstock (FS) comprising water, a first salt, a second salt, and
biomass. The feedstock (FS) is provided to a first
reaction zone (Z1) of a conversion reactor (100), and the primary feedstock is allowed to react in the first
reaction zone at a temperature of at least 350°C and a pressure of at least 160 bar to form a converted primary feedstock. The method includes separating a first salt-rich fraction (SF1), a second salt-rich fraction (SF2), and an oil-rich fraction (OF) from the converted primary feedstock. The method includes withdrawing the oil-rich fraction (OF) from the first
reaction zone (Z1) and withdrawing the first salt-rich fraction (SF1) and the second salt-rich fraction (SF2) from the conversion reactor (100). In the method, the first salt-rich fraction (SF1) comprises at least a portion of a first salt that is dissolved in water, and the second salt-rich fraction (SF2) comprises at least a portion of a second salt in
solid form, and at least one of the first salt and the second salt is a salt that is capable of reacting the
biomass of the primary feedstock (FS) with the water of the primary feedstock (FS) to produce an oil-rich fraction (OF). A device for the same.