Gasifying apparatus with variable gasifier and used as both power generator and combustion boiler, and method of driving the same

A gasifying apparatus comprising:

• a variable gasifier varied such that fuel selected from the group consisting of coal, biomass, RDF, and RPF is fed to perform upflow gasification or downflow gasification;
• a filtration device configured to filter synthesis gas produced by the variable gasifier;
• a feed controller programmed to control a feeding direction of the synthesis gas filtered by the filtration device;
• and
• a combustion boiler and a gas engine configured to be driven with the synthesis gas selectively fed by the feed controller,
• wherein the gasifier comprises:
• an introduction chamber having a fuel feeder formed at a top through which fuel is introduced;
• a gasification chamber positioned under the introduction chamber and a rotary grate formed on the bottom thereof to accumulate the fuel such that gasification is performed and to discharge ash after combustion is completed through the lower side;
• an outer chamber enclosing the gasification chamber, separated from the introduction chamber by a partition, and having an ash discharging hole formed on the bottom;
• a first gasification agent injection hole inserted into the outer chamber to communicate with the gasification chamber and inject the gasification agent during the downflow gasification;
• a second gasification agent injection hole communicating the lower side of the outer chamber and injecting the gasification agent during the upflow gasification;
• and
• a passage opening/closing unit including three directional passages as discharging apertures through which the synthesis gas is discharged from a side of the partition to the introduction chamber, the outer chamber, and the outside, communicating the outer chamber with the synthesis gas discharging hole during the downflow gasification and communicating the introduction chamber with the synthesis gas discharging hole during the upflow gasification for the discharge of the synthesis gas.