A Process for Producing Raw Gas from a Carbonaceous Material in a Combined Two-Stage Process
Publication Date: 2007-Mar-30
The IP.com Prior Art Database
JW van Zyl: AUTHOR [+7]
This invention makes possible the production of pyrolysis products form fine coal, typically <6mm possible through the combination of a carbonizer reactor and a fluidized bed gasifier in an in line / in series configuration. In this process the fine feedstock is carbonized through heat exchange with a product gas that is produced by the gasification of the char that is produced in the pyrolysis step.
THIS INVENTION relates to gasification processes. In particular, it relates to a process for producing raw gas from carbonaceous material, to a process for gasifying a carbonaceous feedstock, and to an installation for gasifying a carbonaceous feedstock.
According to one aspect of the invention, broadly, there is provided a process for producing raw gas from carbonaceous material, the process including
carbonizing the carbonaceous material to form char; and
gasifying the char thereby to produce the raw gas.
In this specification, the term "raw gas" is intended to refer to a fluid obtained by gasifying a carbonaceous material, the fluid including at least one of H2, CO, H2O, benzene, toluene, phenols, organic oils, cresoles, tars and pitches.
The carbonaceous material may be particulate material. The carbonaceous material may be carbonized by contacting it with the raw gas, which is typically at elevated temperature. In the process of contacting the carbonaceous material with the hot raw gas, the composition of the raw gas is modified, thereby producing a modified raw gas.
According to another aspect of the invention, there is provided a process for gasifying a carbonaceous feedstock, the process including
feeding the carbonaceous feedstock, comprising particulate carbonaceous material, into a carbonization stage;
subjecting the carbonaceous feedstock to carbonization conditions in the carbonization stage by contacting the carbonaceous feedstock with a hot raw gas, thereby carbonizing the carbonaceous feedstock to form char and converting the hot raw gas to a modified raw gas;
withdrawing the modified raw gas from the carbonization stage;
feeding the char into a gasification stage;
subjecting the char to gasification conditions in the gasification stage to form ash and said hot raw gas;
feeding said hot raw gas to the carbonization stage; and
discharging the ash from the gasification stage.
Up to about 30 weight % of the carbonaceous feedstock may have a particle size of less than about 6mm, the balance typically being coarser particulate carbonaceous material.
The hot raw gas with which the particulate carbonaceous material is contacted may be at a temperature of between about 600°C and a...