Method for reducing deactivation of a hydrotreatment catalyst

A method for reducing deactivation of a hydrotreatment catalyst, wherein the hydrotreatment catalyst is used as a main active catalyst for producing renewable hydrocarbons by hydrotreatment from a renewable feedstock comprising at least an oxygen containing compound, at least one metal containing compound and at least one phosphorus containing compound as impurities, the renewable feedstock having a metal to phosphorous (M:P) weight ratio, said method comprising:

• i. adjusting the M:P weight ratio of the renewable feedstock to a value within the range from 0.70 to 1.26, measured as elemental metal and elemental phosphorus, to obtain an impurity adjusted renewable feedstock, and
• ii. subjecting the impurity adjusted renewable feedstock to a temperature from 190 to 400° C. under reducing conditions, thereby forming a solid precipitate comprising at least one metal and phosphorus containing compound, and a purified liquid renewable feedstock, and
• iii. contacting the purified liquid renewable feedstock with a main active catalyst, in the presence of hydrogen.