JP3434139B2 - Gas rectifier using dummy tube - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas rectifier using a dummy tube applied to a boiler. 2. Description of the Related Art FIG. 5 is a longitudinal sectional view of a conventional boiler in which gas rectification measures are taken. In the figure, 1 is a boiler casing, 2 is an evaporator tube, 3 is a superheater tube, 5 is a connection portion between a boiler casing and a chimney, 6 is a superheater tube inlet, 7 is an evaporator tube inlet, and 8 is a guide. Vane 9 is the boiler entrance. In the above configuration, the combustion gas entering the boiler horizontally from the boiler inlet 9 changes its direction by 90 ° depending on the shape of the boiler casing 1, and flows vertically upward in the boiler. Thereafter, when passing through the superheater tube 3 and the evaporator tube 2, heat is exchanged with steam and water flowing inside the superheater tube 3 and the evaporator tube 2. Is discharged to the outside through [0004] When the combustion gas passes through the superheater tube 3 and the evaporator tube 2, heat exchange is sufficiently performed, and the evaporation amount of water and the temperature and pressure of the generated steam, which are the performance of the boiler, are ensured as planned. It is necessary that the flow rate of the combustion gas in the cross section of the boiler at the superheater tube inlet 6 and the evaporator tube inlet 7 be uniform. For this reason, in the conventional boiler, the guide vanes 8 are arranged at portions where the combustion gas changes by 90 ° from the horizontal direction to the vertical direction, and the flow velocity of the combustion gas in the cross section at the superheater tube inlet 6 is made uniform. [0005] However, the guide vanes 8 have a drawback that vibrations are generated by the flow of the combustion gas or damage is caused during a long-term operation due to thermal expansion. On the other hand, if the guide vanes 8 are not provided, the unbalance of the flow velocity of the combustion gas in the cross section of the superheater tube inlet 6 is large, and the result is that the performance of the boiler is not ensured. As described above, the guide vane 8 is provided as a rectification measure in a conventional boiler in which the flow direction of the combustion gas changes its direction by 90 ° immediately before the inlet of the superheater tube. And the guide vanes 8 vibrate, thermally expand,
For example, damage occurs during long-term operation. In order to solve the above-mentioned problems, the present invention uniformly distributes the flow rate distribution of the combustion gas in the cross section of the inlet of the superheater tube without disposing the guide vane which is likely to cause such damage. It is an object of the present invention to provide a gas rectifying device that can perform the gas rectification. [0008] Therefore, the present invention provides an evaporator tube and a superheater tube, wherein the boiler in which the combustion gas flows from the superheater tube inlet is provided at the superheater tube inlet. Disclosed is a gas rectifier using a dummy tube, which is provided with a tube having the same outer diameter as the superheater tube, the same pitch, and the same arrangement shape and arranged in a staggered arrangement and performing no heat exchange. In the gas rectifier using the dummy pipe of the present invention described above, the combustion gas entering the boiler is discharged immediately before the inlet of the superheater pipe due to the shape of the boiler casing.
° Can change the direction of flow. At this time, the flow of the combustion gas is largely disturbed because the guide vanes of the prior art are not arranged at the inlet portion, and a large imbalance occurs in the flow velocity distribution of the combustion gas in the subsequent boiler section. The flow of the combustion gas having such a large unbalance of the flow velocity distribution passes through a dummy pipe disposed in front of the superheater pipe. [0010] When the combustion gas passes through the dummy tube, the resistance of the dummy tube and the rectifying effect of the staggered arrangement thereof cause
The imbalance in the flow velocity distribution of the combustion gas is eliminated, and the flow velocity distribution of the combustion gas is equalized at the inlet of the superheater tube, so that the planned boiler performance can be secured. Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a longitudinal sectional view of a boiler to which a gas rectifier using a dummy tube according to an embodiment of the present invention is applied, and FIG. 2 is a sectional view taken along line AA in FIG. In both figures, reference numerals 1 to 3, 5 to 7 have the same functions as conventional ones, and detailed description is omitted, and the description will be made with reference to the drawings as they are. This is described in detail below. In this embodiment, an example is shown in which a dummy pipe is disposed in front of the superheater pipe (upstream of the gas flow) of the gas turbine exhaust heat recovery boiler. In FIG. 1, a dummy pipe 4 is arranged between the superheater pipe inlet 6 and the dummy pipe inlet 19 on the upstream side of the superheater pipe 3 arranged in the boiler casing 1. The dummy tubes 4 have the same pitch and the same arrangement shape as the superheater tubes 3, and are arranged in two staggered rows as shown in FIG. Thus, the gas rectifier is constituted by the casing 1 and the dummy pipe 4. In the boiler provided with the gas rectifier as described above, the gas turbine exhaust gas entering the boiler from the boiler inlet can be turned by 90 ° from the horizontal flow to the vertical flow depending on the shape of the boiler casing 1. At this time, the gas flow is disturbed, and the flow velocity is unbalanced as shown in FIG. In FIG. 3, the horizontal axis represents the distance in the width direction of the boiler, and the vertical axis represents the gas flow velocity. In the width direction of the boiler, the maximum value is 14 m for an average flow velocity of 9 m / sec indicated by a dotted line.
m / sec (+ 55.6% of the average), 3.5 at minimum
An imbalance in flow velocity distribution of m / sec (-61.1% with respect to the average value) has occurred. When the gas turbine exhaust gas passes through the dummy pipe 4, the flow velocity distribution is equalized by the rectification effect, and the cross section of the superheater pipe inlet 6 has the flow velocity distribution in the width direction of the boiler as shown in FIG. Imbalance is reduced. In FIG. 4, as in FIG. 3, the horizontal axis represents the distance in the width direction of the boiler, and the vertical and horizontal axes represent the gas flow velocity. On the other hand, the flow velocity distribution was unbalanced at a minimum value of 7.5 m / sec (16.7% of the average value), and the imbalance was reduced. By arranging them, it is possible to obtain a flow velocity distribution which has no problem on the performance of the boiler. Further, the exhaust heat recovery boiler of the gas turbine according to the present embodiment does not include a rectifying device such as a guide vane, so that an internal space below the boiler (entrance portion) is secured, and maintainability is improved. Has been improved. As described above, the present invention relates to a boiler having a shape in which the gas flow direction changes direction by 90 ° immediately before the inlet of the superheater tube. A gas rectifier in which a heat pipe having the same outer diameter as the superheater pipe and not performing heat exchange is arranged in a staggered arrangement with the same pitch and the same arrangement shape as the superheater pipe on the upstream side of the flow. Because it has, without installing the guide vane, in the cross section of the superheater tube inlet,
The flow velocity distribution of the combustion gas can be equalized to the extent necessary to ensure the performance of the boiler.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a boiler using a gas rectifier using a dummy pipe according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line AA in FIG. FIG. 3 is a gas flow rate distribution diagram in a boiler width direction at a dummy pipe inlet section in FIG. 1; FIG. 4 is a gas flow distribution diagram in a boiler width direction at a superheater tube inlet portion in FIG. 1; FIG. 5 is a longitudinal sectional view of a conventional boiler in which gas rectification measures are taken. [Description of Signs] 1 Boiler casing 2 Evaporator tube 3 Superheater tube 4 Dummy tube 6 Superheater tube inlet 7 Evaporator tube inlet 19 Dummy tube inlet

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F22B 1/18 F23J 11/00 F22B 37/10

Claims (1)

(57) [Claim 1] A superheater tube having an evaporator tube and a superheater tube, wherein the superheater tube is inserted into the superheater tube inlet of a boiler into which combustion gas flows from an inlet of the superheater tube. Same outer diameter, same pitch, same
Gas rectifying device using a dummy tube comprising the tube does not perform heat exchange arranged in staggered array configuration.