Process for liquefying a cellulosic material

Abstract

A process for liquefying a cellulosic material is provided comprising hydrolysing the cellulosic material in the presence of an acid catalyst in a solvent mixture to produce a liquefied product, wherein the solvent mixture contains water and in the range of 5 to 95 wt % of a co-solvent and wherein the co-solvent is present in an amount of less than or equal to 90% by weight based on the weight of water and co-solvent, which co-solvent comprises one or more polar solvents, and wherein the solvent mixture is at least partly recycled.

1 . A process for liquefying a cellulosic material comprising hydrolysing the cellulosic material in the presence of an acid catalyst in a solvent mixture to produce a liquefied product, wherein the solvent mixture contains water and in the range of 5 to 95 wt % of a co-solvent and wherein the co-solvent is present in an amount of less than or equal to 90% by weight based on the weight of water and co-solvent, which co-solvent comprises one or more polar solvents, and wherein the solvent mixture is at least partly recycled. 
     
     
         2 . The process of  claim 1  wherein at least a portion of the solvent mixture is generated in-situ and recycled. 
     
     
         3 . The process of  claim 1  wherein the co-solvent comprises one or more polar solvents having a polarity of log P less than +1. 
     
     
         4 . The process of  claim 1  wherein the co-solvent comprises one or more polar solvents which are obtainable from acid hydrolysis of cellulosic material. 
     
     
         5 . The process of  claim 4  wherein at least a portion of the solvent mixture is generated in-situ and recycled. 
     
     
         6 . The process of  claim 4  wherein the co-solvent comprises one or more polar solvents which are obtainable from the liquefied product by hydrogenation. 
     
     
         7 . The process of  claim 4  wherein the co-solvent comprises one or more polar solvents selected from the group consisting of acetic acid, formic acid, levulinic acid and gamma-valerolactone. 
     
     
         8 . The process of  claim 7  wherein the co-solvent consists of acetic acid, levulinic acid , gamma-valerolactone, or mixtures thereof. 
     
     
         9 . The process of  claim 1  wherein the co-solvent is obtained from the cellulosic material used in the liquefaction process itself. 
     
     
         10 . The process of  claim 1  wherein the co-solvent comprises one or more polar solvent(s), which one or more polar solvents are selected from the group consisting of acetic acid, formic acid, levulinic acid and gamma-valerolactone and which one or more polar solvents is/are generated in-situ by hydrolysis of the cellulosic material, and wherein such one or more polar solvent(s) is/are at least partly recycled. 
     
     
         11 . The process of  claim 1  wherein the acid catalyst is a mineral or organic acid having a pKa below 3.75. 
     
     
         12 . The process of  claim 11  wherein the acid catalyst is sulphuric acid, nitric acid, hydrochloric acid, para toluene-sulphonic acid, phosphoric acid, formic acid or trichloroacetic acid or a mixture thereof. 
     
     
         13 . The process of  claim 1  further comprising hydrogenating the liquefied product. 
     
     
         14 . The process of  claim 1  further comprising a separation step to obtain liquefied product. 
     
     
         15 . The process of  claim 1  further comprising converting the liquefied product to a biofuel. 
     
     
         16 . The process of  claim 15  wherein the liquefied product is at least partially hydrodeoxygenated prior to being subjected to thermal-, catalytic- or hydro-cracking or further hydrodeoxygenation.