Method for processing a mixture of cellulose/plastic waste particles to form a fuel

Abstract

The invention relates to a method for processing a mixture of cellulose/plastic waste particles comprising cellulose and thermoplastic materials. The thermoplastic material constitutes at least 10 weight% of the total weight of the waste mixture The cellu-lose/plastic waste mixture is first dried by treatment with a medium with a temperature in the range of 50 to 150 ° C., wherein the exit temperature of the drying medium has a temperature of 115 ° C. or less. The dried cellulose/plastic waste mixture is then fed to a purification stage, and subjected to the operation of the purification stage. The purification stage comprises at least one separator selected from the group of: wind separator, sieve, metal separator, separator for separating out chlorine- containing components, or a combination thereof.

1 . Method for processing a mixture of cellulose/plastic waste particles comprising cellulose and thermoplastic materials, wherein the thermoplastic material constitutes at least 10 weight % of the total weight of the waste mixture, which method comprises the following steps :
 (a) drying the cellulose/plastic waste mixture by treatment with a medium with a temperature in the range of 50 to 150° C., wherein the water content is reduced to 15 weight % or less ;   (b) wherein the exit temperature of the drying medium has a temperature of 115° C. or less,   (c) feeding the dried cellulose/plastic waste mixture to a purification stage, and   (d) subjecting the dried cellulose/plastic waste mixture to the operation of the purification stage,   wherein the purification stage comprises at least one separators selected from the group of : wind separator, sieve, metal separator, separator for separating out chlorine-containing components, or a combination thereof.   
     
     
         2 . Method according to  claim 1 , wherein the purification step comprises a wind separator. 
     
     
         3 . Method according to any one of the preceding claims, wherein the purification step comprises a sieve. 
     
     
         4 . Method according to any one of the preceding claims, wherein the purification step comprises a chlorine-containing component separator based on NIR technology which is able to remove chlorine-containing plastic parts. 
     
     
         5 . Method according to any one of the preceding claims, wherein the purification step comprises a metal separator. 
     
     
         6 . Method according to any one of the preceding claims, wherein the purification step comprises at least two separators selected from any one of  claims 2 - 5 . 
     
     
         7 . Method according to any one of the preceding claims, wherein the cellulose/plastic waste mixture is transported on a conveyer dryer in order to dry the mixture. 
     
     
         8 . Method according to any one of the preceding claims, wherein the cellulose/plastic waste mixture is fed into a rotary dryer in order to dry the mixture. 
     
     
         9 . Method according to any one of the preceding claims, wherein a dryer medium is used in a drying step, wherein the medium is heated using residual heat. 
     
     
         10 . Method according to any one of the preceding claims, wherein the dryer medium is a gaseous medium. 
     
     
         11 . Method according to any one of the preceding claims, wherein the dryer medium is a gaseous medium consisting at least partly of exhaust gas of an incinerator. 
     
     
         12 . Method according to any one of the preceding claims, wherein the mixture of cellulose/plastic originates from paper recycling. 
     
     
         13 . Method according to any one of the preceding claims, wherein the water content of the cellulose/plastic mixture in step (a) is reduced to 10 weight % or less. 
     
     
         14 . Method according to any one of the preceding claims, wherein the water content of the cellulose/plastic mixture in step (a) is reduced to a value of about 2 weight % or more. 
     
     
         15 . Method according to any one of the preceding claims, wherein the cellulose/plastic waste mixture prior to step (a) is pre-treated by means of mechanical pressing to reduce the water content. 
     
     
         16 . Method according to any one of the preceding claims, wherein the cellulose and thermoplastic material comprise at least 60 weight % of the waste mixture. 
     
     
         17 . Method according to any one of the preceding claims, wherein the thermoplastic material comprises at least 20 weight % of the total weight of the waste mixture. 
     
     
         18 . Method according to any one of the preceding claims, wherein the cellulose/plastic waste mixture comprises less than 40 weight % of thermoplastic material, based on the total dry weight of cellulose and thermoplastic materials. 
     
     
         19 . Method according to any one of the  claims 1 - 16 , wherein the cellulose/plastic waste mixture comprises 40 to 85 weight % of thermoplastic material, based on the total dry weight of cellulose and thermoplastic materials. 
     
     
         20 . Method according to any one of the preceding claims, wherein the cellulose/plastic waste mixture, prior to entering step (a), consists of particles with a particle diameter of maximum about 150 mm or less, and about 60 mm or more. 
     
     
         21 . Method according to any one of the preceding claims, wherein the obtained cellulose/plastic waste mixture comprises less than 8 weight % of inert material. 
     
     
         22 . Method according to any one of the preceding claims, wherein the obtained cellulose/plastic waste mixture comprises less than 0.8 weight % of chlorine. 
     
     
         23 . Method according to any one of the  claims 1 - 22 , further comprising compacting the purified cellulose/plastic waste mixture, such that pellets are obtained. 
     
     
         24 . Method according to  claim 23 , further comprising pulverizing the pellets obtained from the compacting step, in order to obtain a powder.