In-Furnace Gas Injection Port

Abstract

Tertiary nozzle of port for gas injection into furnace includes a contracted flow producing channel provided obliquely toward central axis from the upstream side of gas flow so that the gas flow has a velocity component heading from the outer circumferential side of the port toward the central axis and a velocity component heading along the central axis toward the interior of the furnace, and including louver disposed for guiding so that the gas flows along the surface of throat wall of enlarged pipe configuration wherein the gas channel is enlarged at a furnace wall opening disposed at an outlet area of the contracted flow producing channel. Accordingly, there can be provided a gas injection port that not depending on conditions, such as the flow rate of gas injected from the port, without inviting any complication of apparatus structuring or cost increase, enables preventing of the growth in lump form of clinker caused by ash adhesion and fusion on the wall surface of throat enlarged pipe portion of the furnace.

Description

TECHNICAL FIELD [0001]The present invention relates to a port for gas injection into a furnace such as a boiler, and in particular to a port for gas injection into a furnace such as a boiler advantageous in preventing ash adhesion to a furnace opening.BACKGROUND ART [0002]Various types of ports for injecting gas such as air and exhaust gas into a furnace are disposed on the wall of a furnace such as a boiler. They include, for example, a burner for injecting fuel and combustion air as a combustion apparatus and an after air port (AAP) (which is also referred to as an over firing air port (OFA)) for feeding two-stage combustion air. The gas injection port described in the present specification is not limited to an after air port but includes a port for feeding exhaust gas and a burner port for combusting fuel, as long as it is a port for injecting gas into a furnace. Further, a wall surface of an enlarged pipe configuration opened on a furnace on which the port is disposed is to be r...

AI Technical Summary

Benefits of technology

[0029]Gas guided by the louver as constituted in the invention of claim 1 effectively flows in the vicinity of the wall surface of the throat enlarged pipe portion, thereby eliminating a negative pressure in the vicinity of the wall surface of the enlarged pipe portion. Therefore, gas flowing along the wall surface on the outer circumference (a nozzle partition wall constituting the channel) of the contracted flow producing channel can be effectively guided to the wall surface side of the throat enlarged pipe portion, thereby it is less likely to cause ash adhesion to the throat enlarged pipe portion and the wall surface in the vicinity thereof due to the involvement of ash. Further, conventionally, an injection hole for injecting a coolant such as air is disposed separately at a gas injection port in place of a louver. As compared with the above case, the invention described in claim 1 is able to reduce the pressure loss resulting from gas injection flow by using the louver and simplified in structure, thus eliminating a necessity for providing a sealing air adjustor for preventing the ash adhesion and attaining a reduction in weight of a system and the saving of iron and steel products.

[0044]According to the invention described in claim 7, if the gas injection port is used as an AAP disposed on the furnace wall at the downstream portion of a two-stage combustion burner, no ash is adhered to the furnace wall, thus making it possible to attain a highly reliable fuel combustion which is lower in NOx and CO combustion.

Problems solved by technology

According to conventional techniques, where the contracted flow of the gas injection flow is increased in effects, ash adhesion or growth of clinker is not effectively prevented particularly on a furnace throat wall of a burner port.

According to the description of Patent Document 4, high-pressure injection air for aspiration is used for suppressing partial adhesion of ash to the wall surface of the throat portion with the lapse of time, by which a system may be complicated in structure or there may be an increase in cost and weight.

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