A METHOD FOR PRODUCING A LOW ASH CONTENT BIOFUEL MIXTURE COMPRISING TALL OIL PITCH AND LIGNIN AND USE OF THE BIOFUEL MIXTURE IN A PETROLEUM REFINERY

A method for producing a low ash content biofuel mixture comprising tall oil pitch (TOP) and lignin for use as a renewable feedstock in a petroleum refinery. The method comprises the following steps: - providing a stream of purified TOP with an ash content below 0.1 %; - providing a stream of organosolv lignin， hydrolytic lignin， or purified kraft lignin， said lignin having an ash content below about 0.1 %， wherein the lignin has been purified by at least one of acid refining with an acid， solvent extraction， or solvent dissolution to remove ash from the lignin to a level below 0.1 %; - dissolving the purified lignin in an organic solvent; - mixing the lignin， having an ash content below about 0.1 % and being dissolved in an organic solvent， a surfactant， and the purified TOP in a reactor followed by evaporation of the organic solvent upon heating; and - discharging a pumpable and substantially homogeneous low ash biofuel mixture comprising TOP and lignin from the reactor.