Process for the Preparation of Aromatic Compounds

Abstract

Aromatic compounds are prepared from a feed stream comprising biomass or a mixture of biomass and synthetic polymer in a process, comprising: a) subjecting the feed stream to a pyrolysis treatment in the presence of a cracking catalyst to yield a vaporous fraction comprising hydrocarbons with olefinic unsaturation and oxygen containing organic compounds and coke-laden cracking catalyst; b) separating the vaporous fraction from the coke-laden cracking catalyst; c) contacting the vaporous fraction with a second, aromatization catalyst in a conversion treatment to yield a conversion product comprising aromatic compounds; and d) recovering aromatic compounds from the conversion product, wherein the cracking catalyst is a naturally occurring material, selected from the group consisting of inorganic salts, refractory oxides, minerals, industrial rock and mixtures thereof.

1 . Process for the conversion of a feed stream comprising biomass, the process comprising:
 a) subjecting the feed stream to a pyrolysis treatment in the presence of a cracking catalyst to yield a vaporous fraction comprising hydrocarbons with olefinic unsaturation and oxygen containing organic compounds and coke-laden cracking catalyst;   b) separating the vaporous fraction from the coke-laden cracking catalyst;   c) contacting the vaporous fraction with a catalyst in a conversion treatment to yield a conversion product; and   d) recovering the conversion product,   wherein   (i) the process concerns the preparation of aromatic compounds;   (ii) the process concerns a two-step catalytic process, making use of different catalysts in different steps;   (iii) the cracking catalyst in step (a) is a naturally occurring material, selected from the group consisting of inorganic salts, refractory oxides, minerals, industrial rock and mixtures thereof;   (iv) the catalyst in step (c) is an aromatization catalyst selected from the group consisting of ZSM-5, ZSM-11, ZSM-35, ZSM-23, ferrierite, zeolite beta, zeolite Y, zeolite X, mordenite, zeolite, A. IM-5, SSZ-20, SSZ-55, MCM-22, TNU-9 and combinations thereof; and   (v) aromatic compounds are recovered from the conversion product, by subjecting the conversion product to fractionation, yielding aromatic compounds as separate fraction or fractions and a residue, or by contacting the conversion product with a liquid hydrocarbon to obtain a hydrocarbon phase containing aromatic compounds, and an oxygen-containing compound phase, and separating the hydrocarbon phase from the oxygen-containing compound phase.   
     
     
         2 . Process according to  claim 1 , wherein the cracking catalyst is an amorphous silica alumina. 
     
     
         3 . Process according to  claim 1 , wherein the cracking catalyst is bentonite. 
     
     
         4 . Process according to  claim 1 , wherein the pyrolysis treatment in step a) is carried out at a temperature of 450 to 1000° C. and a pressure of 1 to 6 bar. 
     
     
         5 . Process according to  claim 1 , wherein the pyrolysis treatment in step a) takes place in a fluidized bed or an auger reactor. 
     
     
         6 . Process according to  claim 1 , wherein the coke-laden cracking catalyst is regenerated by contacting the coke-laden cracking catalyst with oxygen to yield a regenerated cracking catalyst. 
     
     
         7 . Process according to  claim 6 , wherein the regenerated cracking catalyst is recycled to the pyrolysis treatment of step a). 
     
     
         8 . Process according to  claim 1 , wherein the feed stream comprises biomass selected from the group consisting of agricultural waste, plants, wood and combinations thereof. 
     
     
         9 . Process according to  claim 1 , wherein the feed stream comprises biomass selected from the group consisting of glucose, maltose, starch, cellobiose, cellulose, hemi-cellulose, other polysaccharides, lignin, sugar cane bagasse, lignocellulosic materials, food waste, animal waste, manure and corn stover. 
     
     
         10 . Process according to  claim 1 , wherein the conversion treatment in step c) is carried out at a temperature in the range of 300 to 1000° C. and a pressure in the range of 1 to 4 bar. 
     
     
         11 . Process according to  claim 1 , wherein the second, aromatization catalyst is a zeolitic catalyst, suitably selected from aluminosilicates, SAPOs, silicalites and combinations thereof. 
     
     
         12 . Process according to  claim 1 , wherein the second, aromatization catalyst is acidic. 
     
     
         13 . Process according to  claim 12 , wherein the second, aromatization catalyst is made acidic by ion exchange with ammonium salts and subsequent calcination. 
     
     
         14 . Process according to  claim 1 , wherein the second, aromatization catalyst has been selected from the group consisting of ZSM-5, ZSM-11, ZSM-35, ZSM-23, ferrierite, zeolite beta, zeolite Y, zeolite X, mordenite, zeolite A, IM-5, SSZ-20, SSZ-55, MCM-22, TNU-9 and combinations thereof. 
     
     
         15 . Process according to  claim 1 , wherein the second, aromatization catalyst comprises an amorphous binder in addition to a zeolite. 
     
     
         16 . Process according to  claim 15 , wherein the amorphous binder has been selected from inorganic refractory oxides, in particular alumina, silica, silica-alumina, titania, zirconia or mixtures thereof, preferably silica-alumina. 
     
     
         17 . Process according to  claim 16 , wherein the amount of amorphous binder in the second, aromatization catalyst is in the range of 0 to 80% wt, based on the weight of the zeolite and the amorphous binder. 
     
     
         18 . Process according to  claim 1 , wherein the conversion treatment is carried out in a fixed bed, a moving bed or a fluidized bed. 
     
     
         19 . (canceled) 
     
     
         20 . Process according to  claim 1 , wherein the residue is combusted to yield energy. 
     
     
         21 . Process according to  claim 1 , wherein the conversion product is subjected to fractionation yielding an olefin fraction. 
     
     
         22 . Process according to  claim 21 , wherein at least part of the olefin fraction is recycled to the conversion treatment or to the pyrolysis treatment or to both. 
     
     
         23 . (canceled)