Pulverized coal injecting apparatus

A pulverized coal injecting apparatus comprising:

• a cylindrical inner pipe for feeding a pulverized coal into a tuyere;
• a cylindrical outer pipe coaxially surrounding said inner pipe;
• a spiral flow path formed on a surface of said inner pipe;
• a pulverized coal being fed through said inner pipe;
• and
• a combustible fluid being fed through between said inner and outer pipes,
• the pulverized coal injecting apparatus further comprising:
• a plurality of dimples formed on a part of a surface of a leading end portion of said inner pipe, W/D being 0.5 to 4, where D indicates a depth of said dimples, and W indicates a width of said dimples.

A pulverized coal injecting apparatus comprising:

• a cylindrical inner pipe for feeding a pulverized coal into a tuyere;
• a cylindrical outer pipe coaxially surrounding said inner pipe;
• a spiral flow path formed on a surface of said inner pipe;
• a pulverized coal being fed through said inner pipe;
• and
• a combustible fluid being fed through between said inner and outer pipes,
• the pulverized coal injecting apparatus further comprising:
• a plurality of dimples formed on a part of a surface of a leading end portion of said inner pipe, said dimples having a depth as large as a thickness of said inner pipe permits.