SYSTEM AND METHOD FOR FLUIDIZED DIRECT REDUCTION OF IRON ORE CONCENTRATE POWDER

摘要

A system and method for the fluidized direct reduction of iron ore concentrate powder. A two-phase fluidized bed is used for the direct reduction of iron ore concentrate powder. Each phase of the fluidized bed is formed by a bubbling bed and a circulating bed. Use of serial-connection processing involving gas and of high-gas-velocity processing of the circulating bed increase the gas utilization rate and the reduction efficiency of single-phase reduction. Once reduced gases are subjected to preheating, each gas is sent into an initial reduction phase and a final reduction phase so as to implement reduction of minerals. Use of mixed-connection processing involving gas appropriately reduces processing pressure. Hot flue gas produced by combustion in a gas heater is sent to a mineral pre-heating system that is used for pre-heating iron ore concentrate powder.

主权项

1. 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; there is provided with a pipeline connecting a feed outlet at the bottom of the second cyclone separator to an inlet of the first cyclone separator, and there is provided with a pipeline 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; there is provided with a pipeline connecting a gas outlet of the first cyclone separator to the inlet of the second cyclone separator, there is provided with 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 there is provide with a pipeline 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 there is provided with 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, there is provided with a pipeline connecting a gas outlet of the fourth cyclone separator to an exhaust gas treatment system, and there is provided with a pipeline 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 there is provided with a pipeline 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, there is provided with 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; there is provided with a pipeline connecting a gas outlet of the eighth cyclone separator to the exhaust gas treatment system, and there is provided with a pipeline 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 there is provided with a pipeline 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 there is provided with a pipeline connecting a discharge port of the discharger to a feed inlet of the product bin.