Abstract: A method for transforming a black liquor, comprising the following steps: a) supplying a black liquor, b) gasifying the black liquor by means of supercritical water gasification in the presence of a hydrogenated carbon-free fuel, by means of which reaction products are formed, c) cooling the reaction products, by means of which a gaseous mixture is obtained which comprises at least methane and a green liquor comprising at least sulphur in the form of NaHS, Na2S and H2S.

Abstract: This sludge drying device is characterised in that a gas entraining a mix of sludge and sand is recycled after drying (6) and separation (8) to be compressed (10) and circulate again through the dryer (6) acting as a heat exchange fluid. Compression has been performed to increase the dew point temperature of the gas containing the evaporated moisture, such that the latent heat of evaporation can be recovered by the drying gas. The required operating power can then be much lower than the required power for evaporating the moisture contained in the sludge, because most of this power is recovered.

Abstract: This sludge drying device is characterised in that a gas entraining a mix of sludge and sand is recycled after drying (6) and separation (8) to be compressed (10) and circulate again through the dryer (6) acting as a heat exchange fluid. Compression has been performed to increase the dew point temperature of the gas containing the evaporated moisture, such that the latent heat of evaporation can be recovered by the drying gas. The required operating power can then be much lower than the required power for evaporating the moisture contained in the sludge, because most of this power is recovered.