NOVELTY - The process involves supplying alkali containing energy rich aqueous solution (120) to an entrained flow gasification reactor (2). The alkali containing energy rich aqueous solution is gasified in the reactor by using an oxidizing medium at sub-stoichiometric conditions and at temperature below 1400 degrees Celsius in an outlet of the reactor. Phase of liquid material and phase of gaseous material are produced in the reactor. Bio-oil (110) is supplied to the reactor. The alkali containing energy rich aqueous solution and the bio-oil are simultaneously gasified in the reactor.    USE - Process for gasifying alkali containing energy rich aqueous solution e.g. spent liquor such as black liquor, sulphite spent liquor (all claimed) e.g. sodium or a potassium based sulphite spent liquor, and white liquor, and powdered or granular form torrefied biomass material, from a pulp mill in an entrained flow gasification reactor to generate energy-rich synthesis gas in a pulp and paper industry.    ADVANTAGE - The process enables gasifying the alkali containing energy rich aqueous solution and the bio-oil together as a mixture in a reaction zone of the gasification reactor to optimize feedstock to be gasified, so that the feedstock with appropriate properties can be efficiently gasified at lower temperature with less energy consuming pre-treatment i.e. evaporation, for the alkali containing energy rich aqueous solution, thus providing higher total energy efficiency process. The process enables the gasification to use syngas, which is potentially more efficient, thus combusting/utilizing original fuel in a flexible manner. The process enables the bio-oil to be added to the alkali containing energy-rich aqueous solution, thus enabling gasification plants with higher capacity than conventional process to be built at the pulp mill, and hence reducing investment cost.    DETAILED DESCRIPTION - The bio-oil is selected from a group consisting of biomass pyrolysis oil and glycerol and liquid by-products i.e. tall oil, from a pulp mill. The phase of gaseous material is raw synthesis gas selected from a group consisting of carbon monoxide, hydrogen, carbon dioxide, methane, hydrogen sulphide and aqueous steam. The oxidizing medium is oxygen or oxygen-containing gas.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a gasification plant.    Entrained flow gasification reactor (2)    Spray nozzle (7)    Conduit (11)    Bio-oil (110)    Alkali containing energy rich aqueous solution (120)