Method for pretreating and using the fine particles of a biomass in a gasification process and an apparatus utilizing said method

Abstract

Method for pretreating the fine particles of a biomass. What is essential in the method is that, for pretreating the fine particles for the gasification, the fine particles are granulated by means of pellet presses or suitable briquetting devices or corresponding granulating devices such that their particle size is advantageous for coking and for the quenching of syngas.

1 . Method for pretreating the fine particles of a biomass characterized in that in the method for pretreating the fine particles for the gasification the fine particles are granulated by means of pellet presses, briquetting devices or other devices suitable for granulation such that their particle size is advantageous for coking and the quenching of syngas. 
     
     
         2 . Method according to  claim 1 , characterized in that in the method the fine particles are pretreated into a pellet, briquette or corresponding product such that they stay intact in the coking reactor without being exposed to the pyrolysis gas, thereby increasing the optimal size of the material to be led to the quenching zone in the method for improving the efficiency ratio of the syngas. 
     
     
         3 . Method according to  claim 1 , characterized in that in the method the fine particles are separated from the raw material flow by screening after drying or by screening before drying from the wet or partially dried biomass. 
     
     
         4 . Method according to  claim 1 , characterized in that in the method a drum dryer is used for drying the fine particles. 
     
     
         5 . Method according to  claim 1 , characterized in that in the method pellets and/or briquettes are most preferably produced of peat, logging residue chips, bark chips or by-products of the wood processing industry, such as sawdust, screening chips or cutter chips or field biomass, such as reed canary grass or straw, as separate clean fine particles or alternatively as mixed pellets and/or briquettes made of one or more type(s) of different fine particles. 
     
     
         6 . Method according to  claim 1 , characterized in that in the method the fine particles are separately separated from the raw material flow, such as from the wood chips and bark chips, into fine particles of their own for producing pellets and/or briquettes and/or other corresponding products. 
     
     
         7 . Method according to  claim 1 , characterized in that preferably 2-5 different fuel feed bins are used in the gasification process according to the method for dispensing raw material, such as wood chips, bark chips and pellets and/or briquettes made of fine particles, suitably proportioned into the reactor. 
     
     
         8 . Method according to  claim 1 , characterized in that the fraction that goes through a screen of 2-20 mm, is used as fine particles in the method, a preferable particle size is in the range 2-10 mm and the particle size of a pellet or briquette produced of said fine particles is in the range 6-16 mm in diameter and the length is approx. 2-4 times the diameter, and the humidity 5-15%, most preferably approx. 10%. 
     
     
         9 . Use of pellet presses, briquetting devices and/or corresponding granulating devices for pretreating the fine particles of a biomass for the gasification. 
     
     
         10 . Use for the purpose of gasification according to  claim 9  such that for achieving suitable syngas the particle size of pellets is advantageous in quenching. 
     
     
         11 . Use for pretreating of fine particles into pellets according to  claim 9  such that they stay intact in the coking reaction without being exposed to the pyrolysis gas, thereby simultaneously increasing the optimal size of the material to be led to the quenching zone for increasing the amount of syngas. 
     
     
         12 . Use according to  claim 9  of a drum dryer used for drying of fine particles. 
     
     
         13 . Apparatus for pretreating the fine particles of a biomass characterized in that the apparatus comprises one or more pellet presses, a suitable briquetting device and/or corresponding granulating device for pretreating the fine particles for the gasification, in which case the fine particles are granulated by means of pellet presses, suitable briquetting devices and/or corresponding granulating devices into a suitable particle size and led such that their particle size is advantageous for coking and the quenching of syngas. 
     
     
         14 . Apparatus according to  claim 13 , characterized in that by means of the apparatus the fine particles are pressed into pellets, briquettes or corresponding granules such that they stay intact in the coking reaction without being exposed to the pyrolysis gas and are led to the quenching zone for increasing the amount of syngas in order to both cool the gas and to achieve a suitable chemical composition (H 2 /CO 2 ). 
     
     
         15 . Apparatus according to  claim 13 , characterized in that with the apparatus the fine particles are separated from the raw material flow by screening after drying or by screening before drying from the wet or partially dried biomass. 
     
     
         16 . Apparatus according to  claim 13 , characterized in that the apparatus comprises one or more screens, through which a fraction of 2-20 mm goes into fine particles, and a pellet press, suitable briquetting device or other corresponding granulating device, the particle size of pellets or briquettes produced in which is in the range 6-16 mm in diameter, most preferably 6-8 mm, and the length is approx. 2-4 times the diameter, and drying, in which the humidity is 5-15%, most preferably approx. 10%. 
     
     
         17 . Apparatus according to  claim 13 , characterized in that the apparatus comprises a number of screens, in which fine particles are separately separated from a different raw material flow, such as from wood chips and bark chips, into fine particles of their own for producing pellets and/or briquettes such that in the gasification process there are preferably 2-5 different fuel feed bins for separately dispensing raw material and pellets and/or briquettes made of fine particles suitably proportioned into the reactor. 
     
     
         18 . Method according to  claim 2 , characterized in that in the method the fine particles are separated from the raw material flow by screening after drying or by screening before drying from the wet or partially dried biomass. 
     
     
         19 . Method according to  claim 2 , characterized in that in the method a drum dryer is used for drying the fine particles. 
     
     
         20 . Method according to  claim 3 , characterized in that in the method a drum dryer is used for drying the fine particles.