An apparatus and a method for gasification of a solid fuel in a fluidized bed gasifier

Abstract

An apparatus and a method for gasification of a solid fuel in a fluidized bed gasifier involving the steps of: introducing first solid material particles and second solid material particles into a turbulent fluidized bed, wherein the particle weight of each of the first solid material particles is greater than the particle weight of each of the second solid material particles; maintaining at least most of the first solid material particles in the turbulent fluidized bed; receiving at least most of the second solid material particles included in the gas-solid mixture in a cyclone; in a return leg conduit, collecting at least most of the solid fuel particles separated from the gas-solid mixture in the cyclone and collecting at least most of the second solid material particles separated from the gas-solid mixture in the cyclone; and feeding at least most of the second solid material particles from the return leg conduit and at least most of the solid fuel particles from the return leg conduit into the turbulent fluidized bed.

1 . A method for gasification of a solid fuel in a fluidized bed gasifier, wherein the fluidized bed gasifier comprises a vessel having a first end section and a second end section, wherein
 the vessel has a longitudinal extension between the first end section of the vessel and the second end section of the vessel, wherein the second end section is located at a level above the first end section, wherein the vessel contains a turbulent fluidized bed in a turbulent fluidized bed region, the turbulent fluidized bed comprising solid fuel particles of the solid fuel to which a gasification medium is added, wherein   a cyclone is in fluid communication with the turbulent fluidized bed region for receiving a gas-solid mixture of a product gas and solid fuel particles from the turbulent fluidized bed, and wherein   a return leg conduit, which has a first end section and a second end section, is fluidly connected to the cyclone via its first end section and fluidly connected to the turbulent fluidized bed region via its second end section, wherein the return leg conduit has a longitudinal extension between its first end section and second end section, wherein the first end section of the return leg conduit is located at a level above the second end section of the return leg conduit, wherein the method comprises:   introducing first solid material particles and second solid material particles into the turbulent fluidized bed, wherein the particle weight of each of the first solid material particles is greater than the particle weight of each of the second solid material particles;   maintaining at least most of the first solid material particles in the turbulent fluidized bed;   receiving at least most of the second solid material particles included in the gas-solid mixture in the cyclone;   in the return leg conduit, collecting at least most of the solid fuel particles separated from the gas-solid mixture in the cyclone and collecting at least most of the second solid material particles separated from the gas-solid mixture in the cyclone; and   feeding at least most of the second solid material particles from the return leg conduit and at least most of the solid fuel particles from the return leg conduit into the turbulent fluidized bed of the vessel.   
     
     
         2 . (canceled) 
     
     
         3 . The method according to  claim 1 , wherein the particle weight of each of the first solid material particles is at least four times greater than the particle weight of each of the second solid material particles. 
     
     
         4 . The method according to  claim 1 , wherein the particle weight of each of the first solid material particles is at least eight times greater than the particle weight of each of the second solid material particles. 
     
     
         5 . The method according to  claim 1 , wherein the particle size of each of the first solid material particles is larger than the particle size of each of the second solid material particles. 
     
     
         6 . The method according to  claim 5 , wherein the particle size of each of the first solid material particles is at least 1.5 times larger than the particle size of each of the second solid material particles. 
     
     
         7 . The method according to  claim 5 , wherein the particle size of each of the first solid material particles is at least three times larger than the particle size of each of the second solid material particles. 
     
     
         8 . The method according to  claim 5 , wherein the particle size of each of the first solid material particles is between 150 μm and 300 μm, and the particle size of each of the second solid material particles is between 50 μm and 100 μm. 
     
     
         9 . The method according to  claim 5 , wherein the particle size of each of the first solid material particles is between 300 μm and 700 μm, and the particle size of each of the second solid material particles is between 50 μm and 250 μm. 
     
     
         10 . The method according to  claim 5 , wherein the particle size of each of the first solid material particles is between 400 μm and 1000 μm, and the particle size of each of the second solid material particles is between 50 μm and 250 μm. 
     
     
         11 . The method according to  claim 1 , wherein the density of each of the first solid material particles is equal to the density of each of the second solid material particles. 
     
     
         12 . The method according to  claim 1 , wherein the density of each of the first solid material particles is larger than the density of each of the second solid material particles. 
     
     
         13 . The method according to  claim 12 , wherein the density of each of the first solid material particles is at least 1.2 times larger than the density of each of the second solid material particles. 
     
     
         14 . (canceled) 
     
     
         15 . (canceled) 
     
     
         16 . (canceled) 
     
     
         17 . (canceled) 
     
     
         18 . The method according to  claim 1 , wherein the turbulent fluidized bed has a top portion and a bottom portion, the top portion being at a level above the bottom portion, and wherein the method is characterized by feeding at least most of the second solid material particles from the return leg conduit and at least most of the solid fuel particles from the return leg conduit into the bottom portion of the turbulent fluidized bed. 
     
     
         19 . The method according to  claim 1 , wherein the vessel of the fluidized bed gasifier, the cyclone and the return leg conduit together form an internal system, wherein an external system is fluidly connected to the internal system, and wherein the introduction of the first solid material particles and the second solid material particles into the turbulent fluidized bed is performed by introducing the first solid material particles and the second solid material particles from the external system into the turbulent fluidized bed located in the turbulent fluidized bed region of the internal system. 
     
     
         20 . The method according to  claim 1 , wherein the vessel of the fluidized bed gasifier, the cyclone and the return leg conduit together form an internal system, wherein an external system is fluidly connected to the internal system, wherein the method is characterized by producing the second solid material particles outside the internal system. 
     
     
         21 . (canceled) 
     
     
         22 . An apparatus for gasification of a solid fuel, wherein the apparatus comprises
 a fluidized bed gasifier in which the gasification of the solid fuel is performed, wherein the fluidized bed gasifier comprises a vessel, wherein the vessel has a first end section and a second end section, wherein the vessel has a longitudinal extension between the first end section and the second end section, wherein the second end section of the vessel is configured to be located at a level above the first end section of the vessel when the apparatus is installed, wherein the vessel has a turbulent fluidized bed region and is configured to contain a turbulent fluidized bed in the turbulent fluidized bed region, the turbulent fluidized bed comprising solid fuel particles of the solid fuel to which a gasification medium is added,   a cyclone in fluid communication with the turbulent fluidized bed region and configured to receive a gas-solid mixture of a product gas and solid fuel particles from the turbulent fluidized bed of the vessel, and   a return leg conduit having a first end section and a second end section, wherein the return leg conduit has a longitudinal extension between its first end section and second end section, wherein the first end section of the return leg conduit is configured to be located at a level above the second end section of the return leg conduit when the apparatus is installed, wherein the return leg conduit is fluidly connected to the cyclone via the first end section of the return leg conduit, wherein the return leg conduit is fluidly connected to the turbulent fluidized bed region via the second end section of the return leg conduit, wherein the apparatus is configured to:   introduce first solid material particles and second solid material particles into the turbulent fluidized bed, wherein the particle weight of each of the first solid material particles is greater than the particle weight of each of the second solid material particles,   maintain at least most of the first solid material particlesin the turbulent fluidized bed,   receive at least most of the second solid material particles included in the gas-solid mixture in the cyclone,   in the return leg conduit, collect at least most of the solid fuel particles separated from the gas-solid mixture in the cyclone and collect at least most of the second solid material particles separated from the gas-solid mixture in the cyclone, and   feed at least most of the second solid material particles from the return leg conduit and at least most of the solid fuel particles from the return leg conduit into the turbulent fluidized bed located in the turbulent fluidized bed region of the vessel.   
     
     
         23 . The apparatus according to  claim 22 , wherein the height (h) of the turbulent fluidized bed region is between 1 and 10 metres when the apparatus is installed. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . The apparatus according to  claim 22 , wherein the cross-sectional area of the turbulent fluidized bed region of the vessel is between 0.05 and 7 m 2 . 
     
     
         36 . The apparatus according to  claim 22 , wherein the vessel, the cyclone and the return leg conduit are configured to be pressurized, and wherein the apparatus is configured such that the pressure of the turbulent fluidized bed in the vessel is at least 10 bar when the apparatus is operated. 
     
     
         37 . (canceled) 
     
     
         38 . (canceled) 
     
     
         39 . (canceled) 
     
     
         40 . (canceled) 
     
     
         41 . (canceled) 
     
     
         42 . (canceled) 
     
     
         43 . A method according to  claim 1 , wherein the material of one or more of the first solid material particles and second solid material particles comprises one or more from the group of:
 silica sand;   olivine; and   magnesite.