Pulverized coal boiler with bottom combustor, and control method therefor

A pulverized-coal boiler with a bottom burner, comprising:

• a furnace;
• at least one burner provided at a bottom portion of the furnace, each of the at least one burner having a burner spout, and primary air carrying pulverized coal to flow through the burner spout upwards into the furnace;
• and
• a secondary air distribution device provided around the at least one burner and arranged at the bottom portion of the furnace, the secondary air distribution device being configured to inject secondary air upwards,
• wherein the secondary air distribution device comprises an internal secondary air distribution device and an external secondary air distribution device;
• wherein the internal secondary air distribution device comprises an internal secondary-air manifold and an internal secondary air duct, the internal secondary air duct is connected to the internal secondary-air manifold and has a plurality of internal secondary air outlets located within the furnace, and at least part of the plurality of internal secondary air outlets are arranged adjacent to the burner spout;
• wherein the external secondary air distribution device comprises an external secondary-air manifold and external secondary air ducts, and the external secondary air ducts are connected to the external secondary-air manifold and each has a plurality of external secondary air outlets located within the furnace;
• and
• wherein the internal secondary-air manifold is independent of the external secondary-air manifold.