System and method for fluidized direct reduction of iron ore concentrate powder

A system for fluidized direct reduction of iron ore concentrate powder, comprising:

• an ore powder bin, a screw feeder, an ore powder preheater, a pre-reduction section feeder, a pre-reduction section fluidized bed, a final reduction section feeder, a final reduction section fluidized bed, a discharger, a product bin, a pre-reduction section gas heater and a final reduction section gas heater;
• wherein the ore powder preheater comprises a first cyclone separator, a second cyclone separator, a cyclone dust collector and a bag dust collector;
• the pre-reduction section fluidized bed comprises a primary bubbling bed body, a third cyclone separator, a fourth cyclone separator, a pre-reduction section inter-bed feeder, a primary circulating bed riser, a fifth cyclone separator, a sixth cyclone separator and a primary circulating dipleg;
• the final reduction section fluidized bed comprises a secondary bubbling bed body, a seventh cyclone separator, an eighth cyclone separator, a final reduction section inter-bed feeder, a secondary circulating bed riser, a ninth cyclone separator, a tenth cyclone separator and a secondary circulating dipleg;
• a feed outlet at the bottom of the ore powder bin is provided with a pipeline which is connected to a feed inlet of the screw feeder, and a feed outlet of the screw feeder is connected to an inlet of the second cyclone separator through a pipeline;
• further comprising a pipeline connecting a feed outlet at the bottom of the second cyclone separator to an inlet of the first cyclone separator, and pipelines connecting the inlet of the first cyclone separator to each of a flue gas outlet of the pre-reduction section gas heater and a flue gas outlet of the final reduction section gas heater;
• further comprising a pipeline connecting a gas outlet of the first cyclone separator to the inlet of the second cyclone separator, and a pipeline connecting a gas outlet of the second cyclone separator to an inlet of the cyclone dust collector, a gas outlet of the cyclone dust collector is connected to an inlet of the bag dust collector through a pipeline, and a gas outlet of the bag dust collector is connected to a flue gas treatment system through a pipeline;
• and further comprising pipelines connecting each of a feed outlet at the bottom of the first cyclone separator, a feed outlet at the bottom of the cyclone dust collector and a feed outlet of the bag dust collector to a feed inlet of the pre-reduction section feeder;
• a discharge port of the pre-reduction section feeder is connected to a feed inlet at the lower portion of the primary bubbling bed body of the pre-reduction section fluidized bed through a pipeline, a gas inlet at the bottom of the primary bubbling bed body is connected to a gas outlet of the sixth cyclone separator through a pipeline, and further comprising a pipeline connecting a gas outlet of the primary bubbling bed body to an inlet of the third cyclone separator;
• a gas outlet of the third cyclone separator is connected to an inlet of the fourth cyclone separator through a pipeline, further comprising a pipeline connecting a gas outlet of the fourth cyclone separator to an exhaust gas treatment system, and pipelines connecting each of a feed outlet at the upper portion of the primary bubbling bed body, a feed outlet at the bottom of the third cyclone separator and a feed outlet at the bottom of the fourth cyclone separator to a feed inlet of the pre-reduction section inter-bed feeder;
• a discharge port of the pre-reduction section inter-bed feeder is connected to a feed inlet at the lower portion of the primary circulating bed riser through a pipeline, a gas inlet at the bottom of the primary circulating bed riser is connected to a gas outlet of the pre-reduction section gas heater through a pipeline, and an outlet at the top of the primary circulating bed riser is connected to an inlet of the fifth cyclone separator through a pipeline;
• a gas outlet at the top of the fifth cyclone separator is connected to an inlet of the sixth cyclone separator through a pipeline, the primary circulating dipleg is provided at the lower portion of the fifth cyclone separator, and a return port at the lower portion of the primary circulating dipleg is connected to a return port at the lower portion of the primary circulating bed riser through a pipeline;
• and further comprising pipelines connecting each of a discharge port at the lower portion of the primary circulating dipleg and a feed outlet at the bottom of the sixth cyclone separator to a feed inlet of the final reduction section feeder;
• a discharge port of the final reduction section feeder is connected to a feed inlet at the lower portion of the secondary bubbling bed body of the final reduction section fluidized bed through a pipeline, a gas inlet at the bottom of the secondary bubbling bed body is connected to a gas outlet of the tenth cyclone separator through a pipeline, further comprising a pipeline connecting a gas outlet of the secondary bubbling bed body to an inlet of the seventh cyclone separator, and a gas outlet of the seventh cyclone separator is connected to an inlet of the eighth cyclone separator through a pipeline;
• further comprising a pipeline connecting a gas outlet of the eighth cyclone separator to the exhaust gas treatment system, and pipelines connecting each of a feed outlet at the upper portion of the secondary bubbling bed body, a feed outlet at the bottom of the seventh cyclone separator and a feed outlet at the bottom of the eighth cyclone separator to a feed inlet of the final reduction section inter-bed feeder;
• a discharge port of the final reduction section inter-bed feeder is connected to a feed inlet at the lower portion of the secondary circulating bed riser through a pipeline, a gas inlet at the bottom of the secondary circulating bed riser is connected to a gas outlet of the final reduction section gas heater through a pipeline, and an outlet at the top of the secondary circulating bed riser is connected to an inlet of the ninth cyclone separator through a pipeline;
• a gas outlet at the top of the ninth cyclone separator is connected to an inlet of the tenth cyclone separator through a pipeline, the secondary circulating dipleg is provided at the lower portion of the ninth cyclone separator, a return port at the lower portion of the secondary circulating dipleg is connected to a return port at the lower portion of the secondary circulating bed riser through a pipeline, and further comprising pipelines connecting each of a discharge port at the lower portion of the secondary circulating dipleg and a feed outlet at the bottom of the tenth cyclone separator to an feed inlet of the discharger;
• and further comprising a pipeline connecting a discharge port of the discharger to a feed inlet of the product bin.