NOVELTY - Manufacturing a low corrosivity renewable diesel range fuel from a liquid stream comprising carboxylic acids with plant origin involves charging the carboxylic acid liquid stream to a distillation unit operating under vacuum of 1 to 100 mbar and at 150 to 280 degrees C to form a stream of distilled and purified carboxylic acids; subjecting the carboxylic acid formed to a treatment in the presence of a heterogeneous decarboxylation catalyst in a reactor or reaction zone to form a stream of decarboxylated renewable diesel range fuel; and separating carbon dioxide containing gases from the fuel.    USE - For manufacturing a low corrosivity renewable diesel range fuel (claimed) useful as an automotive diesel fuel.    ADVANTAGE - The process produces a low corrosivity, low oxygen content diesel range fuel with plant origin that can be used directly as a renewable blending component in mineral diesel fuels or be further treated by for example hydrogen to produce premium diesel range renewable fuels. The process transforms carboxylic acid rich material including hydrolyzed vegetable oils with a free fatty acid content over about 90%, crude tall oil, tall oil rosin, gum rosin oils, acidic oils with origin in vegetable oils and the likes into a low corrosivity, low oxygen content and high cetane bio renewable diesel range fuel. This biocetane can be used as directly as a diesel fuel or be fed to petroleum refinery hydrotreaters where the biocetane is treated with hydrogen for final desulfurization and saturation of unsaturated compounds. The biocetane fuel can be treated by an adsorbent for removal of sulfur compounds and thus form a high quality diesel fuel product ready for use in diesel engine vehicles. Moreover, the renewable diesel product obtained has a high cetane number i.e. 60-100; good physical properties for use directly as a blending component in mineral diesel fuels and low sulfur content.    DETAILED DESCRIPTION - Manufacturing of a low corrosivity renewable diesel range fuel from a liquid stream comprising carboxylic acids with plant origin involves subjecting the carboxylic acid liquid stream to at least three process step includes: a) a liquid stream of carboxylic acids is charged to a distillation unit operating under vacuum of 1 to 100 mbar and at 150 to 280 degrees C, thus forming a stream of distilled and purified carboxylic acids; b) distilled and purified carboxylic acids formed in step a) is subjected to a treatment in the presence of an heterogeneous decarboxylation catalyst in a reactor or reaction zone at 180 to 380 degrees C, at a pressure of 0.1 to 5 MPa and under an hourly space velocity of 0.1 to 5 per hour, thus forming a stream of decarboxylated renewable diesel range fuel with an acid value below 50 mg KOH/g; and c) carbon dioxide containing gases are separated from the decarboxylated liquid renewable diesel range fuel formed in step b) by stripping or by flashing.