Steam injection system

Abstract

A steam jetting system, through structural improvements, can reduce steam temperature fluctuations and improve the accuracy of paper web moisture control. The steam jetting system includes a cooling component, a steam tank, a steam source, and a steam pipeline connecting the steam source and the steam tank. The cooling component includes a condensate tank and a desuperheating valve. The inlet of the desuperheating valve is directly or indirectly connected to the outlet of the condensate tank, and the outlet of the desuperheating valve is connected to the steam pipeline. The cooling component also includes a flow-adjustable return pipeline. The inlet of the return pipeline connects to the outlet of the desuperheating valve and the steam pipeline, and the outlet of the return pipeline is connected to the condensate tank.

Description

Technical Field

[0001] This application relates to the field of papermaking equipment technology, and more specifically, to a steam injection system. Background Technology

[0002] In the papermaking process, the steam box is a key piece of equipment for controlling the moisture content of the paper web, and its operational stability is crucial for ensuring paper quality and production efficiency. However, in traditional technical solutions, the temperature control of the steam box is unstable, resulting in large temperature fluctuations. This prevents the steam box from providing a stable and uniform steam environment for the paper web, thus greatly interfering with the precise control of the paper web's moisture content. Utility Model Content

[0003] The purpose of this invention is to provide a steam jetting system that, by improving the structure of the steam jetting system, can reduce the fluctuation range of steam temperature and improve the accuracy of paper web moisture control.

[0004] To achieve the above objectives, this utility model provides a steam injection system, including a cooling component, a steam tank, a steam source, and a steam pipeline connecting the steam source and the steam tank; the cooling component includes a condensate tank and a desuperheating valve, the inlet of the desuperheating valve being directly or indirectly connected to the outlet of the condensate tank, and the outlet of the desuperheating valve being connected to the steam pipeline; the cooling component also includes a flow-adjustable return pipeline, the inlet of the return pipeline being connected between the outlet of the desuperheating valve and the steam pipeline, and the outlet of the return pipeline being connected to the condensate tank.

[0005] By setting up a return pipeline to divert the condensate discharged from the desuperheating valve and return it to the condensate tank, the opening degree of the desuperheating valve can quickly enter the "better control zone", thereby reducing the fluctuation of steam temperature.

[0006] Optionally, the steam injection system also includes a pressure reducing valve, the outlet of which is connected to the steam pipeline via the pressure reducing valve; it also includes a first temperature detection device installed in the steam pipeline, the first temperature detection device being located between the outlet of the pressure reducing valve and the inlet of the steam box, the pipeline distance between the first temperature detection device and the outlet of the pressure reducing valve being less than the pipeline distance between the first temperature detection device and the inlet of the steam box.

[0007] Optionally, it further includes a second temperature detection device, which is disposed between the first temperature detection device and the inlet of the steam box; the pipeline distance between the second temperature detection device and the outlet of the pressure reducing valve is greater than the pipeline distance between the second temperature detection device and the inlet of the steam box; or, the second temperature detection device is disposed in the steam box.

[0008] Optionally, the cooling assembly also includes a filter unit disposed between the outlet of the condensate tank and the inlet of the desuperheating valve; the filter unit includes a first filter device and a second filter device, wherein the first filter device is located upstream of the second filter device in the direction of condensate flow.

[0009] Optionally, the filtration accuracy of the first filter device is less than that of the second filter device.

[0010] Optionally, the cooling component includes a main condensate pipe and a condensate sub-pipe that can be connected or disconnected; the inlet of the condensate sub-pipe is connected to a first position of the main condensate pipe, the outlet of the condensate sub-pipe is connected to a second position of the main condensate pipe, and a second filter device is disposed between the first and second positions.

[0011] Optionally, the cooling assembly also includes a water pump unit, which is located upstream of the filter unit in the direction of condensate flow.

[0012] Optionally, the cooling assembly also includes a drain pipe that can be connected or disconnected, with the drain pipe inlet located between the outlet of the condensate tank and the inlet of the pump unit.

[0013] Optionally, the condensate tank has a top and a bottom that are vertically opposite each other and a side that connects the top and the bottom; the outlet of the condensate tank is located on the side of the condensate tank.

[0014] Optionally, it also includes a controller, wherein the cooling valve, the first temperature detection device, and the controller are signal-connected.

[0015] Other features and advantages of this specification will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of this specification and, together with their description, serve to explain the principles of this specification.

[0017] Figure 1 This is a schematic diagram of the steam injection system in the embodiments of this application.

[0018] Figure label:

[0019] 1-Cooling component; 11-Condensate tank; 12-Desuperheating valve; 13-Return pipeline; 14-Filter unit; 141-First filter device; 142-Second filter device; 15-Main condensate pipeline; 16-Condensate sub-pipeline; 17-Water pump unit; 18-Drainage pipeline; 2-Steam box; 3-Steam source; 31-Main steam pipeline; 4-Steam pipeline; 51-First temperature detection device; 52-Second temperature detection device; 6-Pressure reducing valve. Detailed Implementation

[0020] To achieve the above objectives, this utility model provides a steam injection system, such as... Figure 1 As shown, Figure 1 This is a schematic diagram of the steam injection system in the embodiments of this application.

[0021] The steam injection system includes a cooling component 1, a steam chamber 2, a steam source 3, and a steam pipeline 4 connecting the steam source 3 and the steam chamber 2. The steam source 3 can be a main steam pipe 31 connected to an external steam supply. The first end of the steam pipeline 4 is connected to the main steam pipe 31, and the last end of the steam pipeline 4 is connected to the steam chamber 2, thereby enabling the steam from the steam source 3 to be delivered into the steam chamber. The cooling component 1 is connected to the steam pipeline 4, thereby cooling the steam entering the steam chamber 2 to meet the production requirements of the paper web.

[0022] The cooling assembly 1 includes a condensate tank 11 for storing condensate and a desuperheating valve 12. The inlet of the desuperheating valve 12 is directly or indirectly connected to the outlet of the condensate tank 11, and the outlet of the desuperheating valve 12 is connected to the steam pipeline 4. The cooling assembly 1 also includes a flow-adjustable return pipeline 13. The inlet of the return pipeline 13 is connected between the outlet of the desuperheating valve 12 and the steam pipeline 4, and the outlet of the return pipeline 13 is connected to the condensate tank 11.

[0023] In this application, condensate is used to cool the steam flowing in the steam pipe 4. The condensate enters the desuperheating valve 12 through the outlet of the condensate tank 11. The desuperheating valve 12 is used to regulate the flow rate of the condensate, and the temperature of the steam entering the steam box 2 is controlled by regulating the flow rate of the condensate using a "deviation regulation" method.

[0024] Both the return pipe 13 and the steam pipe 4 are connected to the outlet of the desuperheating valve 12. In this way, part of the condensate flowing out of the outlet of the desuperheating valve 12 enters the steam pipe 4, and part of it flows back to the condensate tank 11 through the return pipe 13.

[0025] In traditional technical solutions, the temperature of the steam in the steam box fluctuates greatly, for example, the temperature fluctuation range is as high as 8°C to 12°C. This makes it difficult to load the steam box and seriously affects the precise control of the moisture content of the paper web.

[0026] This is because when using a large desuperheating valve, if the demand for condensate is small, the desuperheating valve cannot reach its "optimal control zone," resulting in unstable adjustment of the condensate volume. This leads to large fluctuations in the steam within the steam box, making it difficult to load the steam box.

[0027] The "optimal control zone" refers to the area within which the opening degree of the desuperheating valve falls, and the flow characteristics (such as linear or equal percentage characteristics) of the valve effectively meet the control requirements. A relatively ideal relationship exists between the flow rate and the opening degree, facilitating precise control of the steam temperature. For example, for a linear desuperheating valve, within the "optimal control zone," for every certain percentage increase in opening degree, the flow rate will also increase by the same percentage.

[0028] However, in traditional technical solutions, when the demand for condensate water is too small to match the "better control zone" of the desuperheating valve, a small change in the opening of the desuperheating valve may not cause a significant change in the condensate flow rate, or the change in condensate flow rate may be disproportionate to the change in opening. This results in a decrease in the desuperheating valve's ability to regulate the condensate flow rate, making it impossible to accurately increase or decrease the condensate flow rate according to actual needs. Consequently, the steam temperature is difficult to stabilize at the set value, resulting in large fluctuations.

[0029] In the technical solution of this application, by setting up a return pipeline 13 to divert the condensate discharged from the desuperheating valve 12 and return it to the condensate tank 11, the opening degree of the desuperheating valve 12 can quickly enter the "better control zone", thereby reducing the fluctuation of steam temperature.

[0030] For example, during the specific adjustment process, if the difference between the actual steam temperature and the target temperature is small, the opening degree of the desuperheating valve 12 will be small, and the opening degree of the desuperheating valve 12 cannot be in the "optimal control zone". At this time, the condensate flow rate is unstable, and the actual condensate flow rate may be greater than or less than the condensate flow rate required for temperature adjustment.

[0031] Without a return pipe 13, if the actual condensate flow rate is greater than the required condensate flow rate for temperature regulation, the steam will be excessively cooled. If the actual condensate flow rate is less than the required condensate flow rate for temperature regulation, the desuperheating valve 12 will further adjust its opening. However, since it is not in the "optimal control zone" at this time, the actual condensate flow rate remains unstable. This cycle repeats itself, causing the desuperheating valve 12 to be unable to enter the "optimal control zone" at all times or for a long period of time, resulting in drastic changes in steam temperature.

[0032] After the return pipe 13 is installed, when the actual condensate flow rate is greater than the condensate flow rate required for temperature regulation, part of the condensate is returned to the condensate tank 11, which can reduce or avoid excessive cooling of the steam; when the actual condensate flow rate is less than the condensate flow rate required for temperature regulation, the amount of condensate entering the steam is smaller, which allows the opening of the desuperheating valve 12 to increase more quickly into the "better controlled area", thereby ensuring a stable supply of condensate.

[0033] After the desuperheating valve 12 enters the "better controlled zone", even if the return pipe 13 returns some of the condensate, the actual flow rate of the condensate can still be stably adjusted because the opening of the return pipe 13 remains relatively stable.

[0034] Here, "relatively stable" does not mean that the opening of the return pipe 13 remains constant, but rather that it remains constant under certain operating conditions. In actual operation, those skilled in the art can adjust the opening of the return pipe 13 according to actual operating conditions, such as the difference between the actual steam temperature and the target steam temperature, the opening degree of the desuperheating valve 12 within the "better control zone," and the corresponding flow rate.

[0035] In some other embodiments of this application, the steam injection system further includes a pressure reducing valve 6, and the outlet of the desuperheating valve 12 is connected to the steam pipeline 4 through the pressure reducing valve 6.

[0036] Specifically, one inlet of the pressure reducing valve 6 is connected to the outlet of the steam source 3, and the other inlet is connected to the outlet of the desuperheating valve 12. The outlet of the pressure reducing valve 6 is connected to the inlet of the steam box 2. The pressure reducing valve 6 can atomize the condensate entering it, and the atomized condensate exchanges heat with the steam to cool the steam. The structure of the pressure reducing valve 6 is prior art and will not be described further here.

[0037] The steam injection system also includes a first temperature detection device 51 installed in the steam pipeline 4. The first temperature detection device 51 is located between the outlet of the pressure reducing valve 6 and the inlet of the steam box 2. The pipeline distance between the first temperature detection device 51 and the outlet of the pressure reducing valve 6 is less than the pipeline distance between the first temperature detection device 51 and the inlet of the steam box 2. Here, the pipeline distance refers to the length of the steam pipeline 4, that is, the distance the steam flows.

[0038] The steam injection system also includes a controller (not shown in the figure). The first temperature detection device 51 and the desuperheating valve 12 are connected to the controller via signals. The controller controls the desuperheating valve 12 according to the acquired parameters. The acquired parameters include the actual temperature of the steam, the target temperature of the steam, and the deviation correction value. The first temperature detection device 51 is used to obtain the actual temperature of the steam, and the deviation correction value is the temperature decrease of the steam as it moves from the first temperature detection device 51 into the steam tank 2.

[0039] This can reduce or avoid the problem of temperature regulation lag, and further reduce the fluctuation of steam temperature.

[0040] In this embodiment, the steam injection system further includes a second temperature detection device 52, which is disposed between the first temperature detection device 51 and the inlet of the steam box 2. The pipeline distance between the second temperature detection device 52 and the outlet of the pressure reducing valve 6 is greater than the pipeline distance between the second temperature detection device 52 and the inlet of the steam box 2. The meaning of the pipeline distance here is the same as described above and will not be repeated here. Alternatively, the second temperature detection device 52 may be disposed within the steam box 2.

[0041] The first temperature detection device 51 and the second temperature detection device 52 can be conventional temperature acquisition devices, which can be selected by those skilled in the art.

[0042] By setting a second temperature detection device 52, the steam temperature inside the steam box 2, or the steam temperature about to enter the steam box 2, can be collected, thereby enabling further monitoring of the steam temperature during the operation of the steam injection system.

[0043] In the aforementioned embodiments, the cooling assembly 1 further includes a filter unit 14 disposed between the outlet of the condensate tank 11 and the inlet of the desuperheating valve 12. The filter unit 14 includes a first filter device 141 and a second filter device 142, with the first filter device 141 located upstream of the second filter device 142 in the direction of condensate flow. The first filter device 141 is closer to the condensate tank 11 than the second filter device 142. The filtration accuracy of the first filter device 141 is less than that of the second filter device 142. Herein, "filtration accuracy" refers to the smallest particle diameter that the filter device can trap.

[0044] The condensate from the condensate tank 11 undergoes a primary filtration process, specifically a coarse filtration, to remove large particulate impurities. After passing through the first filtration device 141, the condensate enters the second filtration device 142, which performs a secondary filtration, specifically a fine filtration, to remove smaller impurities. This further protects the desuperheating valve 12.

[0045] In a more specific embodiment, the cooling assembly 1 includes a main condensate drain pipe 15 and a condensate drain sub-pipe 16 that can be connected or disconnected. The inlet of the condensate drain sub-pipe 16 is connected to a first position of the main condensate drain pipe 15, the outlet of the condensate drain sub-pipe 16 is connected to a second position of the main condensate drain pipe 15, and a second filter device 142 is disposed between the first and second positions.

[0046] Because the second filter device 142 has a high filtration precision and is prone to clogging, a condensate sub-pipe 16 was added to facilitate cleaning and replacement of the second filter device 142. During normal operation of the second filter device 142, the condensate sub-pipe 16 is disconnected. When the second filter device 142 requires maintenance, the condensate sub-pipe 16 is connected to the main condensate water pipe 15, thereby enabling online cleaning and replacement of the second filter device 142.

[0047] In another embodiment, the cooling assembly 1 further includes a water pump unit 17, which is located upstream of the filter unit 14 in the direction of condensate flow. In this way, the filter unit 14 can filter the condensate flowing through the water pump unit 17, further protecting the desuperheating valve 12.

[0048] In another embodiment, the cooling assembly 1 also includes a drain pipe 18 that can be connected or disconnected, with the inlet of the drain pipe 18 located between the outlet of the condensate tank 11 and the inlet of the water pump unit 17.

[0049] By setting up a drain pipe 18, impurities in the main condensate pipe 15 located between the condensate tank 11 and the water pump unit 17 can be discharged and flushed, and rust impurities in the main condensate pipe 15 can be removed periodically.

[0050] In another embodiment of this application, the condensate tank 11 has a top and a bottom that are vertically opposite each other and a side portion connected between the top and the bottom; the outlet of the condensate tank 11 is disposed on the side portion of the condensate tank.

[0051] Therefore, water can be drawn from the side of the condensate tank 11, thereby reducing or preventing impurities accumulated at the bottom of the condensate tank 11 from entering the condensate main pipeline 15.

[0052] By adopting the technical solution in this application, the temperature control temperature of the steam in the steam box 2 is reduced from the original 8℃ to 12℃ to fluctuate within the target temperature range by 0.4℃. The steam box 2 is successfully loaded in one go, which is beneficial for the moisture control of the paper web.

[0053] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The above description of the implementation methods is only for the purpose of helping to understand the core ideas of this utility model.

[0054] It should be noted that relational terms such as "first" and "second" are merely used to distinguish one component from another with the same name, and do not necessarily require or imply any actual relationship or order between these components. The foregoing embodiments are for illustrative purposes only. For those skilled in the art, various improvements and modifications can be made to this utility model without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this utility model. Those skilled in the art can also combine the various embodiments in part or in whole, and all technical solutions derived from such combinations fall within the protection scope of this patent.

Claims

1. A steam injection system characterized by, It includes a cooling component (1), a steam box (2), a steam source (3), and a steam pipe (4) connecting the steam source (3) and the steam box (2); The cooling component (1) includes a condensate tank (11) and a desuperheating valve (12). The inlet of the desuperheating valve (12) is directly or indirectly connected to the outlet of the condensate tank (11), and the outlet of the desuperheating valve (12) is connected to the steam pipeline (4). The cooling component (1) also includes a flow-adjustable return pipe (13), the inlet of which is connected between the outlet of the desuperheating valve (12) and the steam pipe (4), and the outlet of which is connected to the condensate tank (11).

2. The steam injection system of claim 1, wherein, The steam injection system also includes a pressure reducing valve (6), and the outlet of the desuperheating valve (12) is connected to the steam pipeline (4) through the pressure reducing valve (6); It also includes a first temperature detection device (51) installed in the steam pipeline (4). The first temperature detection device (51) is located between the outlet of the pressure reducing valve (6) and the inlet of the steam box (2). The pipeline distance between the first temperature detection device (51) and the outlet of the pressure reducing valve (6) is less than the pipeline distance between the first temperature detection device (51) and the inlet of the steam box (2).

3. The steam injection system of claim 2, wherein, It also includes a controller, and the desuperheating valve (12), the first temperature detection device (51) and the controller are connected in signal communication.

4. The steam injection system of claim 2, wherein, It also includes a second temperature detection device (52), which is disposed between the first temperature detection device (51) and the inlet of the steam box (2); the pipeline distance between the second temperature detection device (52) and the outlet of the pressure reducing valve (6) is greater than the pipeline distance between the second temperature detection device (52) and the inlet of the steam box (2); or, The second temperature detection device (52) is installed in the steam box (2).

5. The steam injection system according to any one of claims 1-4, characterized in that, The cooling component (1) further includes a filter unit (14) disposed between the outlet of the condensate tank (11) and the inlet of the desuperheating valve (12); the filter unit (14) includes a first filter device (141) and a second filter device (142), wherein in the direction of condensate flow, the first filter device (141) is located upstream of the second filter device (142).

6. The steam injection system of claim 5, wherein, The filtration accuracy of the first filter device (141) is less than that of the second filter device (142).

7. The steam injection system of claim 5, wherein, The cooling component (1) includes a main condensate pipe (15) and a condensate sub-pipe (16) that can be connected or disconnected; the inlet of the condensate sub-pipe (16) is connected to a first position of the main condensate pipe (15), the outlet of the condensate sub-pipe (16) is connected to a second position of the main condensate pipe (15), and the second filter device (142) is disposed between the first position and the second position.

8. The steam injection system of claim 5, wherein, The cooling component (1) also includes a water pump unit (17), which is located upstream of the filter unit (14) in the direction of condensate flow.

9. The steam injection system of claim 8, wherein, The cooling assembly (1) also includes a drain pipe (18) that can be connected or disconnected, the inlet of which is located between the outlet of the condensate tank (11) and the inlet of the water pump unit (17).

10. The steam injection system of claim 5, wherein, The condensate tank (11) has a top and a bottom that are vertically opposite each other and a side portion connected between the top and the bottom; the outlet of the condensate tank (11) is located on the side portion of the condensate tank (11).

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