Solid fuel in the form of a powder, including a lignocellulosic component

Abstract

The present invention relates to a solid fuel in the form of a powder, including at least one lignocellulosic component in the form of a powder. The present invention also relates to the method for preparing said lignocellulosic component in the form of a powder, as well as to the use thereof in the production of a solid fuel intended for an internal combustion engine or a burner. The invention further relates to a method for generating energy using the solid fuel according to the invention.

1 . A solid fuel, in the form of a powder, characterized in that it comprises at least one lignocellulose constituent in the form of a powder (P):
 the mean diameter and the median diameter (d 50 ) of the particles are between 10 and 30 μm, inclusive, and   the moisture content of the particles is less than or equal to 5% by weight, with respect to the total weight of the powder (P).   
     
     
         2 . The fuel as claimed in  claim 1 , characterized in that more than 70% by weight, of the powder (P) consists of particles having a mean diameter and a median diameter of between 10 and 30 μm, inclusive. 
     
     
         3 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) produces, after combustion, at most 10% by weight of ash, inclusive, with respect to the total weight of the powder (P). 
     
     
         4 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) comprises, after combustion, at most 3% by weight of alumina, with respect to the initial total weight of the powder (P). 
     
     
         5 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) comprises, after combustion, at most 3% by weight of silica, with respect to the initial total weight of the powder (P). 
     
     
         6 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) emits, in the form of volatiles, at least 50% by weight of volatiles, with respect to the total weight of the powder (P). 
     
     
         7 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent originates from herbaceous plants, algae, microalgae, cereal straw, wood, wood grown for energy purposes, wood resulting from waste, other waste of agricultural origin, paper industry waste, or wood and board packaging waste. 
     
     
         8 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent results from cereal straws, in particular from wheat straw, barley straw, oats straw, rye straw or rice straw. 
     
     
         9 . A process for the preparation of a lignocellulose constituent in the form of a powder (P):
 the mean diameter and the median diameter (d 50 ) of the particles of which are between 10 and 30 inclusive, and   the moisture content of the particles of which is less than or equal to 5% by weight of water, with respect to the total weight of the powder (P),   
       characterized in that it comprises the following stages:
 (i) a first stage of grinding cereal straw to obtain a powder (A), the mean diameter and the median diameter (d 50 ) of the particles are greater than 0 and range up to 3000 μm;preferably between 200 and 3000 μm and more 
 (ii) a second stage of grinding the powder (A) resulting from stage (i) to obtain a powder (B), wherein the mean diameter and the median diameter (d 50 ) of the particles are less than or equal to 150 μm and; 
 (iii)a third stage of grinding the powder (B) resulting from stage (ii) to obtain a powder (P), wherein the mean diameter and the median diameter (d 50 ) of the particles are between 10 and 30 μm; and 
 a drying stage being carried out before stage (iii), after stage (iii) or before and after stage (iii). 
 
     
     
         10 . The process as claimed in  claim 9 , characterized in that it satisfies at least one of the following conditions:
 the drying before and/or after stage (iii) is carried out at a temperature of between 30 and 120° C.,   the drying before and/or after stage (iii), is carried out for from 2 to 72 hours   on conclusion of the drying before stage (iii), the powder (B) exhibits a moisture content of less than 5% by weight water, with respect to the total weight of the powder,   the duration of the third grinding stage (iii) is between 1 and 240 hours,   the third grinding stage (iii) is carried out at a temperature of less than or equal to 25° C.,   the third grinding stage (iii) is carried out under argon, nitrogen and/or CO 2 ,   prior to stage (ii), the particles for which the mean diameter and the median diameter (d 50 ) are less than 200 μm are removed from the powder (A) by sieving and/or by a sorting process, or   prior to stage (iii), the particles for which the mean diameter and the median diameter (d 50 ) are less than 20 μm are optionally removed from the powder (B) by sieving and/or by a sorting process.   
     
     
         11 . The use of A method for making a solid fuel intended for an internal combustion engine or for a burner a lignocellulose constituent in the form of a powder (P), the mean diameter and the median diameter of the particles are between 10 and 30 μm, in the manufacture of a solid fuel intended for an internal combustion engine or for a burner. 
     
     
         12 . A process for the production of energy, characterized in that it comprises:
 a) introducing the solid fuel, in the form of a powder, as claimed in any one of  claims 1  to  8 , alone or as a mixture with an oxidizing gas or a liquid fuel in order to form a suspension;   b) passing said fuel or said suspension following a controlled stream close to a source of combustion, and c) triggering the combustion of said fuel or of said suspension and consuming the solid fuel, in the form of a powder, in order to produce energy.   
     
     
         13 . The fuel as claimed in  claim 1 , wherein the mean diameter and the median diameter (d 50 ) of the particles are between 10 and 20 μm, inclusive. 
     
     
         14 . The fuel as claimed in  claim 1 , wherein the moisture content of the particles is less than or equal to 2% by weight of water, with respect to the total weight of the powder (P). 
     
     
         15 . The fuel as claimed in  claim 1 , characterized in that more than 90% by weight of the powder (P) consists of particles having a mean diameter and a median diameter of between 10 and 30 μm, inclusive. 
     
     
         16 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) produces, after combustion, between 0% and 1%, inclusive, by weight of ash, with respect to the total weight of the powder (P). 
     
     
         17 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) comprises, after combustion, between 0% and 1% by weight of alumina with respect to the initial total weight of the powder (P). 
     
     
         18 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) comprises, after combustion, between 0% and 1% by weight of silica, with respect to the initial total weight of the powder (P). 
     
     
         19 . The fuel as claimed in  claim 1 , characterized in that the lignocellulose constituent in the form of a powder (P) emits, in the form of volatiles, at least 80% by weight of volatiles, with respect to the total weight of the powder (P). 
     
     
         20 . The process of  claim 9  wherein:
 the mean diameter and the median diameter (d 50 ) of the particles of which are between 10 and 20 μm, inclusive, and the moisture content of the particles of which is less than or equal to 2% by weight of water, with respect to the total weight of the powder (P).