Apparatus and Method for Gasifying Solid Fuel

Abstract

Apparatus for gasifying a solid fuel that supplies a solid fuel such as coal by dry condition to a gasification furnace of an entrained-bed type is constructed so as to be able to collect the char discharged from the gasification furnace and re-supply the char to the furnace without using a lock hopper and without changing the char into slurry form. The char discharged from the gasification furnace along with produced gases 53 produced in the gasification furnace is brought into contact with water by a gas cooler 9 and collected. After being dehydrated by a dehydrator 10 , the collected char is loaded into a mill 2 or a raw-coal bunker 1. For loading into the raw-coal bunker 1, the char is dried by a drying machine 14, preferably, after the dehydration. According to the present invention, a mixture of the collected char and water can be re-supplied to the gasification furnace without using a lock hopper or a dry feeder. After being dehydrated, the char preferably is further dried and then supplied to the gasification furnace. Since a great deal of moisture is not supplied to the inside of the gasification furnace, it is possible to prevent a temperature of the gasification furnace from decreasing, and thus improve gas conversion efficiency.

1 . Apparatus for gasifying a solid fuel comprising:
 a gasification furnace for gasifying a solid fuel pneumatically transported by causing a reaction thereof upon a gasifying agent;   a solid-fuel storage device for storing the solid fuel to be loaded into the gasification furnace;   a solid-fuel crushing mill for crushing the solid fuel pneumatically transported from the solid-fuel storage device before the solid fuel is loaded into the gasification furnace; and   a solid-substances collecting device for collecting a solid substances discharged from the gasification furnace along with produced gases produced therein;   wherein the solid-substances collecting device includes at least a collecting device of a type which brings the produced gases and water into direct contact with each other, and the solid-substances collecting device is adapted such that a mixture of the water and the solid substances collected by the collecting device is re-supplied at least into either the solid-fuel storage device or the solid-fuel crushing mill after dehydrating of the mixture.   
   
   
       2 . The apparatus for gasifying a solid fuel according to  claim 1 , the apparatus further comprising:
 a transport pipe for transporting the mixture of water and the solid substances collected by the solid-substances collecting device at least to either the solid-fuel storage device or the solid-fuel crushing mill; and a dehydrator disposed midway on the transport pipe.   
   
   
       3 . The apparatus for gasifying a solid fuel according to  claim 2 , wherein the mixture dehydrated by the dehydrator so as to obtain a solid-substances concentration therein greater than 70% by weight is re-supplied to the solid-fuel crushing mill. 
   
   
       4 . The apparatus for gasifying a solid fuel according to  claim 1 , the apparatus further comprising:
 a transport pipe for transporting the mixture of water and the solid substances collected by the solid-substances collecting device to the solid-fuel storage device; a dehydrator and a drying machine for drying the mixture dehydrated by the dehydrator are disposed midway on the transport pipe.   
   
   
       5 . The apparatus for gasifying a solid fuel according to  claim 1 , the apparatus being constructed such that:
 the solid-substances collecting device includes the water-contact type of collecting device and a dry type of dust-removing device; and   the solid substances collected by the solid-substances collecting devices are mixed and then re-supplied at least to either the solid-fuel storage device or the solid-fuel crushing mill.   
   
   
       6 . The apparatus for gasifying a solid fuel according to  claim 5 , the apparatus further comprising:
 a stirring tank for mixing the solid substances collected by the water-contact type of collecting device and the dry type of dust-removing device.   
   
   
       7 . The apparatus for gasifying a solid fuel according to  claim 1 , the apparatus further comprising:
 a condenser for enhancing a concentration of the solid substances by condensing the mixture of water and the solid substances collected by the solid-substances collecting device; and   a dehydrator with a transport pipe for transporting the mixture condensed by the condenser at least to either the solid-fuel storage device or the solid-fuel crushing mill, the dehydrator being disposed midway on the transport pipe.   
   
   
       8 . The apparatus for gasifying a solid fuel according to  claim 7 , wherein the mixture condensed by the condenser so as to obtain a solid-substances concentration greater than 20%-30% by weight is transported to the dehydrator through the transport pipe. 
   
   
       9 . The apparatus for gasifying a solid fuel according to  claim 1 , the apparatus further comprising:
 a mill as the solid-fuel crushing mill having a plurality of crushing rollers;   wherein a flow of the mixture of water and the solid substances collected by the solid-substances collecting device is branched off according to the particular number of crushing rollers, and the branched flow of the mixture is loaded into the mill.   
   
   
       10 . The apparatus for gasifying a solid fuel according to  claim 2 , the apparatus further comprising:
 a water transport pipe for transporting the water separated by the dehydrator to the water-contact type of solid-substances collecting device.   
   
   
       11 . The apparatus for gasifying a solid fuel according to  claim 2 , the apparatus further comprising:
 a water treatment device for removing salt or char by treating the water separated by the dehydrator; and a water transport pipe for transporting the water treated by the water treatment device to the water-contact type of solid-substances collecting device.   
   
   
       12 . Apparatus for gasifying a solid fuel comprising:
 a gasification furnace for gasifying a solid fuel pneumatically transported by causing a reaction thereof upon a gasifying agent;   a solid-fuel storage device for storing the solid fuel to be loaded into the gasification furnace;   a solid-fuel crushing mill for crushing the solid fuel pneumatically transported from the solid-fuel storage device before the solid fuel is loaded into the gasification furnace;   a water-contact type of solid-substances collecting device for cooling gasification furnace produced gases discharged from the gasification furnace by bringing the produced gases into direct contact with water and collecting the solid substances entrained in the produced gases;   a pipe for transporting a mixture of the water and the solid substances collected by the water-contact type of solid-substances collecting device to the solid-fuel crushing mill; and   a dehydrator for forming gel-like solid substances from the mixture transported through the pipe by dehydrating the transported mixture before the mixture is loaded into the solid-fuel crushing mill.   
   
   
       13 . Apparatus for gasifying a solid fuel comprising:
 a gasification furnace for gasifying a solid fuel pneumatically transported by causing a reaction thereof upon a gasifying agent;   a solid-fuel storage device for storing the solid fuel to be loaded into the gasification furnace;   a solid-fuel crushing mill for crushing the solid fuel pneumatically transported from the solid-fuel storage device before the solid fuel is loaded into the gasification furnace;   a water-contact type of solid-substances collecting device for cooling gasification furnace produced gases discharged from the gasification furnace by bringing the produced gases into direct contact with water and collecting the solid substances entrained in the produced gases;   a pipe for transporting a mixture of the water and the solid substances collected by the water-contact type of solid-substances collecting device to the solid-fuel crushing mill;   a dehydrator for forming gel-like solid substances from the mixture transported through the pipe by dehydrating the transported mixture before the mixture is loaded into the solid-fuel crushing mill; and   a drying machine for drying the gel-like solid substances obtained by the dehydrator.   
   
   
       14 . A method for gasifying a solid fuel comprising the steps of:
 a gasifying process for gasifying a solid fuel pneumatically transported by causing a reaction thereof upon a gasifying agent;   a collecting process for collecting solid substances along with gasification furnace produced gases discharged from the gasification furnace, by bringing the produced gases into direct contact with water;   a dehydrating process for dehydrating a mixture of the water and solid substances collected in the collecting process; and   a transporting process for transporting the mixture whose solid-substances concentration has been enhanced in the dehydrating process at least into either a solid-fuel storage device for storing the solid fuel or a solid-fuel crushing mill for crushing the solid fuel.   
   
   
       15 . The method for gasifying a solid fuel according to  claim 14 , wherein, the transporting process is transporting the mixture dehydrated in the dehydrating process to the solid-fuel crushing mill. 
   
   
       16 . The method for gasifying a solid fuel according to  claim 14 , wherein, the drying process is drying the mixture dehydrated in the dehydrating process; and
 the transporting process is transporting the mixture dried in the drying process to the solid-fuel storage device.   
   
   
       17 . The method for gasifying a solid fuel according to  claim 14 , wherein, regardless of a load of the gasification furnace, an overall amount of solid substances collected in the collecting process is loaded at least into either the solid-fuel storage device or the solid-fuel crushing mill, 
   
   
       18 . Apparatus for gasifying a solid fuel, comprising:
 a gasification furnace for producing produced gases with main components of hydrogen and carbon monoxide by causing oxygen or air to react upon a pulverized solid fuel; and   a particle collector for collecting particulates contained in the produced gases discharged from the gasification furnace;   wherein the particle collector includes a container for introducing the produced gases thereinto, means for collecting particulates in the produced gases by bringing the produced gases and liquid into contact with each other in the container, a stirrer for stirring collection liquid dwelling in a bottom section of the container, and   a pump for extracting slurry formed up of the collection liquid and the particulates from a bottom section of the collector and supplying the slurry to an interior of the gasification furnace.   
   
   
       19 . The apparatus for gasifying a solid fuel according to  claim 18 , wherein the gasification furnace is a two stage gasification furnace with a burner disposed at an upper stage and lower stage thereof, the burners being oriented in a tangent direction of the gasification furnace such that the produced gases form a swirling stream.