JPH01184309A - Over-heating reducer - Google Patents

Abstract

PURPOSE:To enable an axial length of a pipe required for evaporation of cooling water and the like by a method wherein a cooling medium injection port is formed in such a way as the medium is injected in a circumferential direction in respect to an inner circumference of an inner protective cylinder arranged within a temperature reducer. CONSTITUTION:A protective inner cylinder 2 is arranged within a temperature reducer 1, at least one of spray nozzles 3a and 3b projected into the protective inner cylinder is arranged so as to form coolant medium injection ports 4a and 4b to cause the cooling medium from the spray nozzles to be injected in a circumferential direction in respect to the inner surface of the protective inner cylinder. Coolant medium such as cooling water injected from the coolant medium injection ports 4a and 4b is injected in a circumferential direction at the inner surface of the protective inner cylinder 2, then moved in a flowing direction by over-heated fluid such as over-heated steam and the like to form a liquid film within the protective inner cylinder 2 and then it receives a heat from the over-heated fluid and evaporated. As a result, a rate of evaporation of the cooling medium is high and an effect of reducing temperature of the over-heated fluid is high, resulting in that an axial length of the pipe required for a temperature reducer can be excessively shortened.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a superheat reducer, and particularly relates to a superheat reducer that sprays a cooling medium such as cooling water in a cylinder installed in a pipe for superheated fluid such as superheated steam to superheat the fluid. The present invention relates to an attemperator that reduces the temperature of a fluid.

[Conventional technology]

Conventionally, a cooling water spray type such as a steam atomization type, a swirl spray type, or a pressure spray type is widely used as a superheat reducer.

In this case, the spray of cooling water should be as fine and uniform as possible to speed up the evaporation rate of the cooling water due to superheated steam, shorten the axial length of the pipe required for the wake steam piping, and reduce heat transfer to the steam piping. It is desired to reduce stress generation.

However, in the case of the cooling water spray type, the sprayed water droplets become uniform in velocity with the steam flow immediately after being sprayed due to the resistance force received from the superheated steam flow, and the evaporation rate rapidly decreases because the relative speed with the steam flow is lost. Furthermore, since the sprayed water droplets flow through the cylinder at the same speed as the steam flow, their residence time in the attemperator is extremely short. Therefore, in the case of a cooling water spray type desuperheater, there is a problem that the effect of reducing superheated steam is low and the length of the pipe in the axial direction becomes long.

Furthermore, in the case of a cooling water spray type desuperheater, there is a problem in that thermal shock occurs due to the collision of the cooling water with the steam piping constituting the desuperheater main body. In order to solve this problem, a protective inner cylinder is installed inside the steam piping that makes up the desuperheater body, and by making the protective inner cylinder sufficiently long, cooling can reach the downstream piping side without evaporation. It is necessary to reduce the amount of water and suppress the occurrence of thermal shock in downstream piping.

[Problem to be solved by the invention]

As mentioned above, in the case of conventional cooling water spray type desuperheaters, a structural function is required to atomize the cooling water into a fine spray in the steam flow, and the spray cooling water impinges on the downstream piping. In order to suppress the thermal shock that occurs due to this, the length of the piping in the axial direction of the pipe for evaporating the sprayed cooling water is required, which imposes restrictions on the arrangement.

The purpose of the present invention is to solve the problems of the prior art described above,
To provide a spray-type superheat reducer for cooling water, etc., which can shorten the axial length of piping required for evaporation of cooling water, etc., without requiring a complicated spray atomization function. It is in.

[Means for Solving the Problems] The above object is to provide a protective inner cylinder in the desuperheater, provide one spray nozzle protruding into the protective inner cylinder, and provide a cooling medium from the spray nozzle. This is achieved by forming a cooling medium jet port so that the cooling medium is jetted against the inner surface of the protective inner cylinder in the circumferential direction thereof.

[Effect]

The cooling medium such as cooling water spouted from the cooling medium spout formed in the spray nozzle protruding from the protective inner cylinder is jetted in the circumferential direction on the inner surface of the protective inner cylinder, and then the superheated fluid is absorbed by superheated fluid such as superheated steam. moves in the direction of flow and forms a liquid film inside the protective inner cylinder.

This liquid film receives heat from superheated fluid such as superheated steam and evaporates. As a result, the evaporation rate of the cooling medium is high, and the temperature reduction effect of the superheated fluid is increased. Therefore, the required length of the attemperator in the tube axis direction can be significantly shortened.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing an embodiment of the desuperheater of the present invention;
FIG. 2 is a sectional view taken along line A--A in FIG. 1.

In this attenuator, spray nozzles 2 are attached to both radial ends of desuperheater main body piping 1, and the tips of the spray nozzles 2 connect to desuperheater main body piping 1 via support members 8a and 8b. It protrudes into the inside of the protective inner cylinder 2 arranged concentrically. The jet nozzle 4a formed in the spray nozzle 3a and the jet nozzle 4b formed in the spray nozzle 3b protruding into the inside of the protective inner cylinder 2 are each formed in a plane perpendicular to the flow direction of the superheated steam flow 5 in the spray nozzle. Both are arranged at symmetrical positions from the center point of the protective inner cylinder 2.

Next, the operation of the superheat reducer configured as described above will be explained.

Superheated steam introduced from a predetermined pipe into the desuperheater main body pipe 1 becomes a superheated steam flow 5 and is introduced into the protective inner cylinder 2. On the other hand, the flow of cooling water whose flow rate is controlled by a cooling water flow adjustment valve (not shown) that operates based on a signal from a temperature transmitter (not shown) installed downstream of the desuperheater is indicated by the arrow in the figure. The cooling water is injected into the spray nozzles 3a and 3b from the injection direction indicated by 6, and is ejected into the protective inner cylinder 2 from the respective spout ports 4a and 4b.

The cooling water spouted from the spouts 4a and 4b first flows through the second
As shown by the cooling water injection direction 7 in the figure, the protective inner cylinder 2
flows circumferentially along the inner surface of the

At this time, the superheated steam flow 5 flowing inside the protective inner cylinder 2 pushes the steam toward the downstream side, and forms a cooling water film inside the protective inner cylinder 2 while flowing in the cooling water film flow direction 9 as shown in FIG. It forms, receives heat from the superheated steam stream 5, evaporates, and lowers the temperature of the superheated steam.

The cooling water film protects the inner cylinder 2 from the superheated steam flow 5 due to the resistance force.
Although it flows in the same direction as the superheated steam flow 5 on the inner surface of the superheated steam flow 5, the flow velocity becomes smaller than the flow velocity of the superheated steam flow 5 because it simultaneously receives the frictional force from the protective inner cylinder 2. For this reason, in the case of conventional cooling water spray type attemperators, the sprayed cooling water droplets immediately move at the same velocity as the superheated steam flow after being sprayed, so the residence time in the desuperheater is short, and the speed of the sprayed cooling water droplets becomes constant with the superheated steam flow. There is no relative velocity and low heat transfer between the cooling water and the superheated steam stream. However, in this embodiment, the residence time of the cooling water in the protective inner cylinder 2 is long, and the relative velocity between the cooling water and the superheated steam flow 5 is also large.
Heat transfer will be higher. As a result, the water evaporation rate in the axial direction of the desuperheater is significantly improved compared to the conventional cooling water spray type desuperheater, and the length required for the desuperheater piping in the axial direction of the pipe can be shortened. Can be done.

In the above example, in order to form an effective cooling water film, the piping dimensions are set so that the maximum superheated steam flow rate is 20 to 50 m/s, and the cooling water spray speed is set to 10 to 20 m/s.
It is desirable to set it to m/s. Further, it is desirable that the spray direction and the steam flow direction form an angle of 80 to 90 degrees in the direction of the inner surface of the protective inner cylinder 2. As a result, the cooling water evaporation rate in the length direction of the desuperheater can be increased to 150 to 200% of that of conventional cooling water spray type superheat desuperheaters, and as a result, the tube axis required for the desuperheater is Direction length 2/3~1/
It is possible to shorten the time to 2.

In the above-mentioned embodiments, an example was shown in which cooling water was sprayed in order to particularly reduce superheated steam, but the present invention provides a method for spraying cooling water to reduce the temperature of superheated fluid (gas) other than superheated steam. It can also be applied to attemperators that use cooling media (liquids).

Furthermore, in the above-described embodiment, two spray nozzles were installed, but in the present invention, the number of spray nozzles protruding into the protective inner cylinder is one, or three or more at equal intervals in the circumferential direction of the protective inner cylinder. It may be installed.

〔effect〕

As described above, according to the present invention, the temperature of the superheated fluid can be reduced by evaporation from the liquid film of the cooling liquid along the protective inner cylinder installed inside the attemperator, and the temperature of the superheated fluid can be reduced compared to the conventional cooling water spray method. The evaporation rate of cooling water can be significantly improved compared to other superheat reducers.

In addition, the spray nozzle may be partially protruded from the protective inner cylinder, and an injection port may be provided so that the cooling medium from the spray nozzle is jetted along the circumferential direction of the inner surface of the protective inner cylinder. The structure of can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the desuperheater of the present invention;
2 is a sectional view taken along the line A-A in FIG. 1, and FIG. 3 is an explanatory diagram showing the flow direction of the cooling water film in the attemperator of FIG. 1. 1... Desuperheater main body piping, 2... Protective inner cylinder, 3 a. 3b...Spray nozzle, '4a, 4b...
... Injection port, 5 ... Superheated steam flow, 6 ...
...Cooling water injection direction, 7...Cooling water injection direction,
8a, 8b...Supporting member, 9...Cooling water film flow direction. Agent Patent Attorney Masaru Nishimoto −

Claims (1)

[Claims] (1) In a desuperheater that reduces the temperature of the superheated fluid by introducing a cooling medium into the desuperheater installed in the middle of the superheated fluid piping, a protective inner cylinder is provided inside the desuperheater, and this At least one spray nozzle protruding into the protective inner cylinder is provided, and a cooling medium outlet is formed so that the cooling medium from the spray nozzle is jetted against the inner surface of the protective inner cylinder in the circumferential direction. Features a superheat reducer.