1. A waste incineration facility comprising: an incinerator that incinerates waste; 5 a flue gas passage through which a flue gas discharged from said incinerator flows; a dust collector provided in said flue gas passage; a recirculating flue gas line that is connected to a discharge position located downstream of said dust collector in said flue gas passage and that takes out, as a 10 recirculating flue gas, part of said flue gas flowing through said flue gas passage to supply said recirculating flue gas into said incinerator; and an oxygen mixer that mixes said recirculating flue gas flowing through said recirculating flue gas line with a high-concentration oxygen gas that has a higher oxygen concentration than air. 15

2. The waste incineration facility as claimed in claim 1, wherein said recirculating flue gas that has been mixed with said highconcentration oxygen gas serves as a main gas of a gas for combustion that is supplied via a gas pipe into said incinerator. 20

3. The waste incineration facility as claimed in claim 1, wherein said recirculating flue gas line is connected to a primary combustion chamber and/or a secondary combustion chamber of said incinerator, and said recirculating flue gas that has been mixed with said high25 concentration oxygen gas is used as a gas for primary combustion and/or a gas for secondary combustion. 40

4. The waste incineration facility as claimed in claim 1, further comprising: a dehydrator that is provided in said recirculating flue gas line and that removes water from said recirculating flue gas. 5 5. The waste incineration facility as claimed in claim 1, further comprising: a preheater that is provided in said recirculating flue gas line and that heats said recirculating flue gas.

6. The waste incineration facility as claimed in one of claims 1 to 5, 10 comprising: a wet scrubber that is provided between said dust collector and said discharge position in said flue gas passage and that supplies a liquid containing water to said flue gas to remove a predetermined component from said flue gas, wherein said recirculating flue gas flowing through said recirculating flue 15 gas line is heated by heat exchange with said flue gas flowing upstream of said wet scrubber in said flue gas passage.

7. The waste incineration facility as claimed in one of claims 1 to 5, comprising: 20 a waste pit that reserves waste that is before being disposed of into said incinerator; and a drawn-off gas line through which a gas in said waste pit is drawn off as a drawn-off gas, wherein said oxygen mixer generates said high-concentration oxygen gas 25 from at least part of said drawn-off gas and mixes said high-concentration oxygen gas with said recirculating flue gas flowing through said recirculating flue gas line. 41

8. The waste incineration facility as claimed in claim 7, wherein said oxygen mixer generates said high-concentration oxygen gas by condensing oxygen contained in said drawn-off gas and discharges a remainder of said drawn-off gas via a deodorizer to an outside. 5

9. The waste incineration facility as claimed in one of claims 1 to 5, comprising: a carbon dioxide collector that is provided downstream of said discharge position in said flue gas passage and that collects carbon dioxide from said flue gas; 10 and a processed gas line by which at least part of said flue gas that has passed through said carbon dioxide collector is mixed with said recirculating flue gas flowing through said recirculating flue gas line. 15 10. The waste incineration facility as claimed in claim 9, wherein said oxygen mixer is provided in said processed gas line and generates said high-concentration oxygen gas from said flue gas that has passed through said carbon dioxide collector, and mixes said high-concentration oxygen gas with said recirculating flue gas flowing through said recirculating flue gas line.

We claim:
1. A waste incineration facility comprising:
an incinerator that incinerates waste;
5 a flue gas passage through which a flue gas discharged from said
incinerator flows;
a dust collector provided in said flue gas passage;
a recirculating flue gas line that is connected to a discharge position located
downstream of said dust collector in said flue gas passage and that takes out, as a
10 recirculating flue gas, part of said flue gas flowing through said flue gas passage to
supply said recirculating flue gas into said incinerator; and
an oxygen mixer that mixes said recirculating flue gas flowing through
said recirculating flue gas line with a high-concentration oxygen gas that has a
higher oxygen concentration than air.
15
2. The waste incineration facility as claimed in claim 1, wherein
said recirculating flue gas that has been mixed with said highconcentration oxygen gas serves as a main gas of a gas for combustion that is
supplied via a gas pipe into said incinerator.
20
3. The waste incineration facility as claimed in claim 1, wherein
said recirculating flue gas line is connected to a primary combustion
chamber and/or a secondary combustion chamber of said incinerator, and
said recirculating flue gas that has been mixed with said high25 concentration oxygen gas is used as a gas for primary combustion and/or a gas for
secondary combustion.
40
4. The waste incineration facility as claimed in claim 1, further comprising:
a dehydrator that is provided in said recirculating flue gas line and that
removes water from said recirculating flue gas.
5 5. The waste incineration facility as claimed in claim 1, further comprising:
a preheater that is provided in said recirculating flue gas line and that heats
said recirculating flue gas.
6. The waste incineration facility as claimed in one of claims 1 to 5,
10 comprising:
a wet scrubber that is provided between said dust collector and said
discharge position in said flue gas passage and that supplies a liquid containing
water to said flue gas to remove a predetermined component from said flue gas,
wherein said recirculating flue gas flowing through said recirculating flue
15 gas line is heated by heat exchange with said flue gas flowing upstream of said wet
scrubber in said flue gas passage.
7. The waste incineration facility as claimed in one of claims 1 to 5,
comprising:
20 a waste pit that reserves waste that is before being disposed of into said
incinerator; and
a drawn-off gas line through which a gas in said waste pit is drawn off as
a drawn-off gas,
wherein said oxygen mixer generates said high-concentration oxygen gas
25 from at least part of said drawn-off gas and mixes said high-concentration oxygen
gas with said recirculating flue gas flowing through said recirculating flue gas line.
41
8. The waste incineration facility as claimed in claim 7, wherein
said oxygen mixer generates said high-concentration oxygen gas by
condensing oxygen contained in said drawn-off gas and discharges a remainder of
said drawn-off gas via a deodorizer to an outside.
5
9. The waste incineration facility as claimed in one of claims 1 to 5,
comprising:
a carbon dioxide collector that is provided downstream of said discharge
position in said flue gas passage and that collects carbon dioxide from said flue gas;
10 and
a processed gas line by which at least part of said flue gas that has passed
through said carbon dioxide collector is mixed with said recirculating flue gas
flowing through said recirculating flue gas line.
15 10. The waste incineration facility as claimed in claim 9, wherein
said oxygen mixer is provided in said processed gas line and generates said
high-concentration oxygen gas from said flue gas that has passed through said
carbon dioxide collector, and mixes said high-concentration oxygen gas with said
recirculating flue gas flowing through said recirculating flue gas line.