A process for converting a solid biomass material comprising minerals to a high quality bio-oil in high yield, said process comprising: (a) subjecting said solid biomass to a pretreatment step to produce a pretreated solid biomass, said pretreatment step comprising a method selected from the group consisting of: (i) at least partially demineralizing said solid biomass; (ii) improving the accessibility of said solid biomass by opening the texture of the particles of said solid biomass; and (iii) a combination of steps (i) and (ii); (b) subjecting said pretreated solid biomass to a pyrolysis step in the presence of a catalyst to produce a bio-oil having a Total Acid Number of y and a yield of x, such that the ratio x/y is greater than 1.5, wherein the TAN is less than 30, wherein the catalyst is in form of solid dry particles and comprises a zeolite, wherein the pretreatment step is carried out in a mixer, a mill, a grinder, or a kneader, wherein the pyrolysis step is carried out in a fluid bed reactor, a moving bed reactor, or a cyclone reactor, wherein the demineralization of step (i) comprises contacting said solid biomass with a solvent so as to dissolve at least part of the minerals present in said solid biomass and at least partially removing said solvent from said solid biomass, wherein the step of improving the accessibility of said solid biomass of step (ii) comprises one of the following: contacting said solid biomass with a fluid under pressure, and subsequently releasing the pressure, or heating said solid biomass in an oxygen-poor or oxygen-free atmosphere to a temperature in the range of from 90 to 300 °C. (a) subjecting said solid biomass to a pretreatment step to produce a pretreated solid biomass, said pretreatment step comprising a method selected from the group consisting of: (i) at least partially demineralizing said solid biomass; (ii) improving the accessibility of said solid biomass by opening the texture of the particles of said solid biomass; and (iii) a combination of steps (i) and (ii); (b) subjecting said pretreated solid biomass to a pyrolysis step in the presence of a catalyst to produce a bio-oil having a Total Acid Number of y and a yield of x, such that the ratio x/y is greater than 1.5, wherein the TAN is less than 30, wherein the catalyst is in form of solid dry particles and comprises a zeolite, wherein the pretreatment step is carried out in a mixer, a mill, a grinder, or a kneader, wherein the pyrolysis step is carried out in a fluid bed reactor, a moving bed reactor, or a cyclone reactor, wherein the demineralization of step (i) comprises contacting said solid biomass with a solvent so as to dissolve at least part of the minerals present in said solid biomass and at least partially removing said solvent from said solid biomass, wherein the step of improving the accessibility of said solid biomass of step (ii) comprises one of the following: contacting said solid biomass with a fluid under pressure, and subsequently releasing the pressure, or heating said solid biomass in an oxygen-poor or oxygen-free atmosphere to a temperature in the range of from 90 to 300 °C. wherein the pretreatment step is carried out in a mixer, a mill, a grinder, or a kneader, wherein the pyrolysis step is carried out in a fluid bed reactor, a moving bed reactor, or a cyclone reactor, wherein the demineralization of step (i) comprises contacting said solid biomass with a solvent so as to dissolve at least part of the minerals present in said solid biomass and at least partially removing said solvent from said solid biomass, wherein the step of improving the accessibility of said solid biomass of step (ii) comprises one of the following: contacting said solid biomass with a fluid under pressure, and subsequently releasing the pressure, or heating said solid biomass in an oxygen-poor or oxygen-free atmosphere to a temperature in the range of from 90 to 300 °C. contacting said solid biomass with a fluid under pressure, and subsequently releasing the pressure, or heating said solid biomass in an oxygen-poor or oxygen-free atmosphere to a temperature in the range of from 90 to 300 °C.