TECHNICAL FIELD

The present invention relates to a combustor.

Priority is claimed on Japanese Patent Application No. 2018-053512, filed Mar. 20, 2018, the content of which is incorporated herein by reference.

BACKGROUND ART

For example, gas turbines are composed of a compressor, a combustor, and a turbine. The gas turbines compress air with the compressor to produce high-temperature and high-pressure compressed air. In the combustor, fuel is supplied to the compressed air and combusted, and the turbine is driven by the high-temperature and high-pressure combustion gas. Additionally, in the gas turbines, it is possible to drive a generator coupled to the turbine to generate power.

Additionally, there are also combined power generation systems in which a gasification furnace is applied to such gas turbines. In the combined power generation system, a solid fuel or a liquid fuel is gasified in the gasification furnace, and the generated gas is sent as a fuel to a gas turbine and combusted. The generated combustion gas drives the turbine to generate power. Additionally, a high-temperature emission gas discharged from the gas turbine is sent to the boiler to generate steam, and the steam turbine is driven by the generated steam to generate power.

Meanwhile, in the above-described combined power generation systems, the emission gas discharged from the gas turbine contains carbon dioxide (CO2).

Patent Document 1 describes a combined power generation system in which a gasification furnace and a closed gas turbine that mixes an emission gas with gas fuel and oxygen to combust the mixed gas are combined with each other. In the combined power generation system, oxygen is mixed in the emission circulation gas discharged from the compressor and combusted in a combustor. Additionally, in the combined power generation system, oxygen is input immediately before a combustion region in consideration of the safety and pressure loss of the combustor.

CITATION LIST

Patent Literature

[Patent Document 1]

Japanese Unexamined Patent Application, First Publication No. 2011-94573

SUMMARY OF INVENTION

Technical Problem

Patent Document 1 describes the combustor that supplies oxygen adjacent to both a radially inner side and a radially outer side of the gas fuel. The combustor promotes the mixing of the gas fuel and oxygen to realize efficient combustion.

Meanwhile, in the field of combustors, there is a demand for further improving the combustion state.

The present invention provides a combustor capable of further improving a combustion state.

Solution to Problem

According to a first aspect of the present invention, a combustor includes a combustion cylinder having a tubular shape centered on an axis; a fuel supply unit that has a tubular shape centered on the axis and is configured to inject fuel from an upstream side with respect to the combustion cylinder, the fuel supply unit defining an inner peripheral side space into which an inert gas is introduced on a radially outer side of the axis and which is configured to supply the inert gas to the combustion cylinder and defining an outer peripheral side space into which the inert gas is introduced on a radially outer side around the axis and which is configured to supply the inert gas to the combustion cylinder; an inner peripheral side oxygen supply unit that is configured to supply oxygen to the inner peripheral side space; an outer peripheral side oxygen supply unit that is configured to supply oxygen to the outer peripheral side space; and an adjustment unit that is configured to adjust relative amounts of the oxygen supplied by the inner peripheral side oxygen supply unit and the oxygen supplied by the outer peripheral side oxygen supply unit.

According to such a configuration, by adjusting the relative amounts of the oxygen supplied to the inner peripheral side space and the oxygen supplied to the outer peripheral side space, it is possible to bring the oxygen concentration closer to a more suitable oxygen concentration in accordance with the combustion state of the fuel. Accordingly, the CO concentration of the combustion gas can be reduced.

In the above combustor, the adjustment unit may individually adjust a supply amount of the oxygen supplied from the inner peripheral side oxygen supply unit and a supply amount of the oxygen supplied from the outer peripheral side oxygen supply unit.

According to such a configuration, the optimal oxygen concentration can be set according to the combustion state of the fuel.

In the above combustor, the inner peripheral side oxygen supply unit may have a tubular inner peripheral side nozzle that extends in an axial direction, and a plurality of inner peripheral oxygen injection holes disposed at a tip of the inner peripheral side nozzle, and the plurality of inner peripheral oxygen injection holes may be disposed as close to the radially outer side as possible, and the outer peripheral side oxygen supply unit may have a tubular outer peripheral side nozzle that extends in the axial direction, and a plurality of outer peripheral oxygen injection holes disposed at a tip of the outer peripheral side nozzle, and the plurality of outer peripheral oxygen injection holes may be disposed as close to the radially inner side as possible.

According to such a configuration, since the oxygen concentration on the fuel supply unit side increases, the combustion of fuel is promoted, and the CO concentration of the combustion gas can be further reduced.

In the above combustor, the inner peripheral side oxygen supply unit may have a tubular inner peripheral side nozzle that extends in an axial direction, and a plurality of inner peripheral oxygen injection holes disposed at a tip of the inner peripheral side nozzle, the outer peripheral side oxygen supply unit may have a tubular outer peripheral side nozzle that extends in the axial direction, and a plurality of outer peripheral oxygen injection holes disposed at a tip of the outer peripheral side nozzle, and positions of the plurality of inner peripheral oxygen injection hole in the axial direction may be different from positions of the plurality of outer peripheral oxygen injection holes in the axial direction.

In the above combustor, the positions of the plurality of inner peripheral oxygen injection holes in the axial direction may be disposed downstream with respect to the positions of the plurality of outer peripheral oxygen injection holes in the axial direction.

According to such a configuration, the combustibility of the fuel and oxygen is activated on the inner peripheral side to improve the flame holding property, and the flame temperature is suppressed on the outer peripheral side. For that reason, a temperature rise on the wall surface side of the combustion cylinder can be suppressed.

In the above-mentioned combustor, the combustor may further include a CO concentration measurement device that is configured to measure a CO concentration of a combustion gas flowing in the combustion cylinder, the adjustment unit may increase a supply amount of the oxygen by the inner peripheral side oxygen supply unit and decrease a supply amount of the oxygen by the outer peripheral side oxygen supply unit in a case where a CO concentration at a central portion in the combustion cylinder is higher than a CO concentration on the radially outer side in the combustion cylinder and may decrease the supply amount of the oxygen of the inner peripheral side oxygen supply unit and increase the supply amount of the oxygen of the outer peripheral side oxygen supply unit in a case where the CO concentration at the central portion in the combustion cylinder is lower than the CO concentration on the radially outer side in the combustion cylinder.

Advantageous Effects of Invention

According to the present invention, by adjusting the relative amounts of the oxygen supplied to the inner peripheral side space and the oxygen supplied to the outer peripheral side space, it is possible to bring the oxygen concentration closer to a more suitable oxygen concentration in accordance with the combustion state of the fuel. Accordingly, the CO concentration of the combustion gas can be reduced.

