Biomass combustion burner, biomass-mixed fired boiler, and biomass fuel combustion method

Patent metadata

Field	Value
Publication number	US-10309647-B2
Application number	US-201214368917-A
Country	US
Kind code	B2
Filing date	Dec 11, 2012
Priority date	Dec 26, 2011
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

The present invention provides a biomass combustion burner applied to a pulverized coal-fired boiler to burn biomass fuel, a biomass-mixed fired boiler that reduces an amount of CO2 derived from fossil fuels, and a method for burning biomass fuel using the foregoing. The biomass combustion burner includes a biomass fuel jet nozzle having a fuel jet port that jets biomass fuel conveyed by primary air; a secondary air nozzle having a secondary air jet port that surrounds the fuel jet port; and a tertiary air nozzle having a tertiary air jet port that surrounds the secondary air jet port. The biomass fuel jet nozzle includes a fuel concentration adjusting section that changes a biomass fuel stream into a swirl flow to thereby make a fuel concentration higher on an outer circumferential portion side; and a degree-of-swirl adjusting plate that reduces a degree of swirl of a jetting fuel stream.

First claim

The invention claimed is:

1. A method for burning biomass fuel, comprising:
burning biomass fuel using a biomass combustion burner,
the biomass combustion burner comprising:
a biomass fuel jet nozzle having a bent section and a fuel jet port that jets biomass fuel conveyed by primary air;
a secondary air nozzle having a secondary air jet port that surrounds an opening in the fuel jet port, the secondary air nozzle jetting secondary air; and
a tertiary air nozzle having a tertiary air jet port that surrounds the secondary air jet port, the tertiary air nozzle jetting a swirl flow of tertiary air, wherein

the biomass combustion burner includes a swirler disposed at a center inside the biomass fuel jet nozzle, the swirler changing a biomass fuel stream drifted by the bent section into an axially whirling swirl flow to thereby make a fuel concentration lower on a pipe axis side and higher on an outer circumferential portion side, and includes a degree-of-swirl adjusting plate disposed on a pipe inner wall immediately upstream of the fuel jet port, the degree-of-swirl adjusting plate reducing a degree of swirl of the fuel stream that jets from the fuel jet port, thereby optimizing a fuel concentration distribution,
the fuel jet port has a funnel-shape that widens the biomass fuel stream outwardly,
the secondary air jet port has a funnel-shape that widens a secondary air stream outwardly,
the secondary air jet port is disposed upstream of the fuel jet port,
an opening in the secondary air jet port and an opening in the tertiary air jet port are adjusted to reduce an amount of the secondary air and a buffer stream is thereby formed between the fuel stream and a tertiary air stream,
the biomass fuel is burned by supplying the biomass combustion burner with a fuel stream that contains woody biomass fuel exhibiting a grain size distribution of 2 mm or under, the woody biomass fuel being conveyed by the primary air such that fuel conveying air including the primary air has an A/C value that is:
not less than 0.8, and
not greater than proportional distribution between A/C 2.5 in a quantity of fuel of burner rating and A/C 1.5 in a quantity of fuel of 60% of the burner rating, and

the A/C value is a ratio of fuel conveying air flow rate (Nm 3 /h) to fuel (kg/h), the fuel conveying air being equal to the primary air.

2. The method for burning biomass fuel according to claim 1 , wherein the primary air is supplied in such a quantity as to result in a velocity of a fuel conveying stream in the pipe of the biomass fuel jet nozzle falling within a range of from 15 m/s to 25 m/s.

Assignees

• Kawasaki Heavy Ind Ltd

Inventors

• Taniguchi Koji
• Kato Atsunori
• YABARA Suguru
• Tanabe Yutaka

Classifications

• F23G2201/80

  Shredding · CPC title

• F23D1/00

  Burners for combustion of pulverulent fuel · CPC title

• F23G2209/26

  Biowaste · CPC title

• F23C99/00

  Subject-matter not provided for in other groups of this subclass · CPC title

• F23G5/033 Primary

  comminuting or crushing · CPC title