Damage-proof device for steam inlet of plate heat exchanger

Abstract

The utility model discloses an anti-damage device for a steam inlet of a plate heat exchanger. A flow equalizing header is arranged between the steam inlet of the plate heat exchanger and a plate core cladding; the flow equalizing header is provided with a plurality of steam outlets; the flow equalizing header comprises a box body communicated with the steam inlet, a steam outlet distribution plate is arranged in the box body, and a plurality of steam outlets are formed in the steam outlet distribution plate; arc-shaped grooves for absorbing deformation are pressed in the transverse and longitudinal directions of the steam outlet distribution plate; and holes are formed in the transverse and longitudinal intersections of the arc-shaped grooves so as to break metal deformation stress generated by machining the arc-shaped grooves. According to the utility model, the steam at the inlet of the heat exchanger is slowed down and redistributed, so that the blown-in steam is not easy to damage a plate core bag and is more uniformly distributed in the core bag, and meanwhile, the temperature reduction and the impact resistance can be considered.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of for plate heat exchanger steam inlet's anti-damage device. BACKGROUND

[0002] In traditional industry, including heavy industry and light industry, steam is widely used as a common energy carrier. Since steam itself has a certain temperature and pressure, a large amount of latent heat is released during the phase change of steam (not limited to water vapor). Steam is also suitable for transportation, so in recent years, steam has been widely used as a heat source in industry.

[0003] With the development of plate heat exchanger technology, a large number of equipment have been widely used in steam-gas, steam-steam and steam-liquid heat exchange fields. Plate heat exchangers are increasingly used due to their small size, high heat exchange efficiency, and low material consumption. However, in the use of plate heat exchangers with steam as a heat source, damage and cracking of plate packs and plate bundles are often found, which directly affects the promotion of plate heat exchangers in applications with steam as a medium, thus losing the benefits of an excellent device. In view of this, the inventor starts from the damage reasons of existing equipment and proposes and discovers an anti-damage device for the steam inlet of a plate heat exchanger.

[0004] Taking a thermal power plant as an example, through analysis of the steam-heated heat network first station and the raw water heater, it is found that the damage to the plate heat exchanger is caused by the following reasons:

[0005] The flow rate of the steam inlet is too high. Although the inlet pipe diameter of the plate heat exchanger usually meets the design specifications, due to the small size of the plate heat exchanger and the volume strength limitation, the steam inlet pipe diameter is relatively small compared to the tube heat exchanger, and the flow rate is high. This brings the following problems: 1. The high speed of the steam inlet causes a large impact on the steam inlet. Especially the welded part between the plates, which is easy to crack under impact. 2. Due to the high flow rate of the steam inlet, the hard debris such as welding slag in the steam pipeline is given a very high speed. After the steam inlet, the high-speed impact on the plate core package causes plate damage. 3. Due to the high flow rate of the steam, there is not enough time and space for the steam to fill and evenly distribute in the space from the steam inlet to the plate core package. Most of the steam fills the windward core package, while the core package far from the steam inlet does not get enough steam, which also causes uneven thermal stress.

[0006] When the steam is superheated steam, its temperature is higher, and the temperature of the cold source of the cold side is lower, resulting in a larger temperature difference between the cold side and the hot side of the heat exchanger. Due to the limited tolerance of the material to the cold-hot temperature difference, the heat stress crack of the heat exchange plate is caused. Although the superheated steam becomes saturated steam after heat exchange, the temperature decreases, but the heat stress damage is still caused in the part of the heat exchange plate sheet under the action of the local superheated steam.

[0007] The above two reasons are the most important reasons affecting the safe operation of the plate heat exchanger. The following invention is also based on solving the above problems. SUMMARY

[0008] The purpose of the utility model is to provide a kind of steam for the heat exchanger entrance to slow down and redistribute, so that steam is not easy to damage plate core package when blowing in, and more evenly distributed in the core package for the heat exchanger steam entrance Anti-damage device.

[0009] The technical solution of the utility model is:

[0010] A kind of anti-damage device for the heat exchanger steam entrance, characterized by: flow equalizing header is arranged between the heat exchanger steam inlet and plate core package;The steam outlet of flow equalizing header is multiple;Flow equalizing header includes the box body communicated with steam inlet, steam outlet distribution plate is arranged in the box body, and multiple steam outlets are arranged on steam outlet distribution plate;Arc-shaped groove for absorbing deformation is pressed in the horizontal and vertical direction of steam outlet distribution plate;At the horizontal and vertical intersection of the arc-shaped groove, hole is taken to unload the metal deformation stress generated by machining arc surface groove.

[0011] Temperature reducing and heat exchange device is arranged on the outside or inside of steam outlet distribution plate;The temperature reducing and heat exchange device adopts surface heat exchanger to reduce the temperature of steam before entering plate core package.

[0012] Anti-impact device is installed on the plate group of plate core package in one or more outlet corresponding parts of steam outlet distribution plate;The anti-impact device is fixed on the outer edge of plate group, and adopts arc-shaped roof shape or sharp roof shape structure.

[0013] The utility model slows down and redistributes the steam for the heat exchanger entrance, so that steam is not easy to damage plate core package when blowing in, and more evenly distributed in the core package. For the problem of too fast flow rate of local nozzle, plate group anti-impact device is arranged in the corresponding plate group. At the same time, in order to overcome the thermal stress caused by the large temperature difference of superheated steam, temperature reducing and heat exchange device is installed on the inside or outside of flow equalizing header, so that superheated steam is further cooled to approach or become saturated steam. This method can not only increase the flow resistance of steam too much, but also better utilize steam heat and temperature, and ensure the safe and stable operation of heat exchanger. BRIEF DESCRIPTION OF DRAWINGS

[0014] The utility model will be further described below in combination with the drawings and examples.

[0015] Figure 1 is the structure schematic diagram of one embodiment of the utility model.

[0016] Figure 2 is the left view of Figure 1 .

[0017] Figure 3 is the plan view of Figure 1 .

[0018] Figure 4 is the B-B view of Figure 3 .

[0019] Figure 5 is the structure schematic diagram of steam outlet distribution plate.

[0020] Figure 6 is the A-A view of Figure 5 .

[0021] Figure 7 is the B-B view of Figure 5 .

[0022] Figure 8 is the C-C view of Figure 5 .

[0023] Figure 9 is the structure schematic diagram of temperature reducing heat exchange device.

[0024] Figure 10 is the plan view of Figure 9 .

[0025] Figures 11-14 is the structure schematic diagram of anti-impact device.

[0026] Among them: Figure 12 is the A-A view of Figure 11 . Figure 13 is the partial enlarged view containing anti-impact device from the B-B direction section view of Figure 3 . Figure 14 is the partial enlarged view containing anti-impact device from the plan view of steam inlet downward. DETAILED DESCRIPTION

[0027] A kind of anti-damage device for plate heat exchanger steam inlet, flow-collecting header 2 is arranged between plate heat exchanger steam inlet 1 and plate core package;Steam outlet of the flow-collecting header is multiple, so that steam is as evenly as possible distributed to heat exchanger core package.

[0028] The flow-equalizing header comprises a header body communicating with a steam inlet, a steam outlet distribution plate 3 is arranged in the header body, and a plurality of steam outlets are arranged on the steam outlet distribution plate; after the steam enters from the steam inlet, the steam fills the flow-equalizing header body and flows out from the plurality of steam outlets on the steam outlet distribution plate, so as to achieve the purpose of more uniform entering into the plate core package.

[0029] When the steam enters along the inlet of the flow-equalizing header, the steam does not directly enter the plate core package of the plate heat exchanger, but enters the header body of the flow-equalizing header, and then flows out from the openings on the steam outlet distribution plate as steam outlets. Since there are a plurality of openings on the steam outlet distribution plate, the steam will flow out along these openings, and is relatively uniformly distributed into the plate core package, because the header body with the steam distribution plate constitutes a steam distributor, just like a shower head. If there is no shower head, water is directly sprayed out with concentrated force but is not uniform. With the shower head, water is sprayed out through more spray openings, and becomes dispersed, gentle and uniform, so that better utilization effect is obtained. The above describes the basic principle of the flow-equalizing header, and in actual application, the size, dimensions, steam parameters, flow, openings, dimension distribution of the header, steam outlet distribution plate and the like need to be calculated, simulated, checked and designed in detail, so as to obtain ideal use effect. The spray openings are preferably circular, and can also be square, rectangular and the like. Usually, the openings are equidiameter, and when necessary, wedge-shaped spray openings with bevels can also be used to obtain good gas dynamic performance. Although there are a plurality of spray openings, they are not necessarily uniformly distributed and equidiameter. They can be designed and arranged according to actual conditions, which will not be listed one by one here.

[0030] When the distribution plate is large, the effect of thermal stress should be considered. Measures are taken to prevent thermal stress deformation of the steam outlet distribution plate. In this paper, a measure is taken, that is, an arc-shaped groove is pressed in the transverse and longitudinal directions of the distribution plate to absorb deformation. The intersection of the arc-shaped groove in the transverse and longitudinal directions can be provided with an opening to release the metal deformation stress generated by machining the arc surface groove.

[0031] Another reason for the damage of the core pack and the plate is the thermal stress damage of the plate material caused by the large temperature difference between the cold medium and the steam. In some cases, the temperature of the superheated steam reaches 350℃. While the temperature of the cold side inlet is less than 100℃, the temperature difference above 200℃ causes thermal stress damage of the plate material, resulting in cracks, open welding and other phenomena. Therefore, effectively reducing the superheat degree of the steam to reduce the temperature difference between the cold and hot sides is one of the measures to improve the life of the plate and the core pack. In practical applications, water spray is often used to reduce the temperature. There are two shortcomings of water spray. 1. It is difficult to control the amount of water spray. If too much water is sprayed, the water droplets in the mixed gas will cause damage to the plate and reduce the quality of the steam. If too little water is sprayed, the temperature reduction effect is not good. 2. Water spray cannot effectively make the heat exchanger obtain the temperature of the superheated section, resulting in a loss of cold side temperature raising effect. Therefore, we need a method that can not only reduce the temperature, but also make good use of the steam temperature to achieve the temperature raising effect. A temperature reducing heat exchange device 4 is arranged on the outside or inside of the steam outlet distribution plate. The temperature reducing heat exchange device uses a surface heat exchanger to achieve the above purpose, such as a plate heat exchanger, a tube heat exchanger, etc. can achieve the above effect. Taking the tube heat exchanger as an example, a small amount of tube heat exchanger tube bundles can be arranged on the inside or outside of the steam outlet distribution plate of the flow distribution header (arranged on the inside or outside, determined according to the specific situation). When the steam before or after temperature reduction passes through the tube bundle, the cold side medium in the tube bundle will reduce the temperature of the steam to approach or become saturated steam. Thus, the temperature of the medium on the cold and hot sides after the steam enters the plate heat exchanger core pack meets the thermal stress requirements of the material. A good method is that the cold medium in the tube bundle can use the same cold medium as the plate heat exchanger, such as water heated by steam, and the medium can be all or part of the medium heated by the plate heat exchanger.

[0032] This has the following advantages:

[0033] The medium after being heated by the plate heat exchanger and the steam after being reduced in temperature further reduce the temperature difference and the thermal stress.

[0034] The medium after being heated by the plate heat exchanger can enter the tube bundle for further heating to obtain a higher temperature. Unlike water spray, the temperature gradient between saturated steam and superheated steam is wasted. The cold medium heated by the tube bundle flows out together with part or all of the cold medium heated by the plate.

[0035] Even if the steam outlet distribution plate is installed, there is still a possibility that high-speed steam flow will be ejected onto the plate core pack through the opening of the steam outlet distribution plate opposite to the steam inlet. In this case, the steam-facing surface of the plate group needs to be protected. The anti-impact device 5 is used in the utility model.

[0036] The anti-impact device is generally in arc or triangular shape, which has excellent flow guiding effect, can guide the impact steam to flow into the gap between the plates to be condensed, and prevent the steam from damaging and tearing the weld between the plates on the plate group. At one or more outlets of the steam outlet distribution plate, an anti-impact device is selectively installed on the plate group of the plate core package (i.e. at the corresponding part of the plate group of the plate core package of the one or more outlets of the steam outlet distribution plate). The anti-impact device is fixed on the outer edge of the plate group and has an arc roof shape or a pointed roof shape, which prevents the steam from directly impacting the plate group and causing the plate group to be open-welded or damaged.

[0037] A pressure, temperature and / or flow monitoring device is arranged at the steam side inlet. Automatic monitoring and adjustment can be achieved to obtain the best temperature reduction effect and the maximum temperature increase effect.

Claims

1. A damage prevention device for the steam inlet of a plate heat exchanger, characterized in that: A flow equalization header is provided between the steam inlet and the plate core of the plate heat exchanger; the flow equalization header has multiple steam outlets; the flow equalization header includes a box body communicating with the steam inlet, and a steam outlet distribution plate is provided in the box body, with multiple steam outlets on the steam outlet distribution plate; arc-shaped grooves for absorbing deformation are pressed in the transverse and longitudinal directions of the steam outlet distribution plate; openings are made at the intersection of the transverse and longitudinal directions of the arc-shaped grooves to relieve the metal deformation stress generated by machining the arc-shaped grooves.

2. The anti-damage device for the steam inlet of a plate heat exchanger according to claim 1, characterized in that: in A de-cooling heat exchange device is provided on the outer or inner side of the steam outlet distribution plate; the de-cooling heat exchange device adopts a surface heat exchanger to cool the steam before it enters the plate core.

3. A damage prevention device for the steam inlet of a plate heat exchanger according to claim 1, characterized in that: in An anti-impact device is installed on the plate core of the steam outlet distribution plate at one or more outlet locations; the anti-impact device is fixed on the outer edge of the plate core and adopts an arc-shaped or pointed roof-shaped structure.

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