The invention provides a circulating
fluidized bed coal gasification multi-stage cooling and dedusting process and device. In the process, a mixture of semicoke and high-temperature
coal gas generated by a circulating
fluidized bed gasifier is subjected to gas-
solid separation through a
cyclone separator, then the semicoke is returned to the gasifier through a return device at the bottom of the
cyclone separator to continue participation in reaction while the high-temperature
coal gas enters a tube side of a shell-and-tube
heat exchanger, and low-temperature air enters a shell side of the shell-and-tube
heat exchanger and absorbs
heat energy transferred by the
coal gas in heat exchange tubes; heated high-temperature air enters the bottom of the gasifier to be used for gasification; cooled low-temperature
coal gas is subjected to multi-stage cooling and dedusting through a
waste heat boiler,
cyclone dust removal,
heat pipe heat exchange, bag dust removal and
heat pipe cooling prior to being used in subsequent procedures. In the process, the high-temperature
coal gas discharged from the gasifier is subjected to cyclone separation and then exchanges heat with air without flowing through the
waste heat boiler, the temperature of air serving as a gasifying agent is raised while a heat value of the coal gas is increased, high safety in technical operation is achieved, and great cooling and dedusting effects can be achieved by combination with multi-stage subsequent heat exchange and dedusting procedures.