Industrial steam supply system and steam supply method

Abstract

The present invention relates to an industrial steam supply system and a steam supply method, comprising a thermal power generating set and a hot re-extraction unit for extracting hot re-steam from the thermal power generating set, and also comprising a cold re-extraction unit and a heat exchange mixing unit; the cold re-extraction unit is used to extract cold re-steam from the thermal power generating set; the cold re-extraction unit and the hot re-extraction unit are both connected to the heat exchange mixing unit through a pipeline, so that the cold re-steam transported from the cold re-extraction unit and the hot re-steam transported from the hot re-extraction unit pass through the heat exchange mixing unit to form steam supplied to users. The beneficial effect is that the present invention uses the cold re-steam in the thermal power generating set to exchange heat and mix with the hot re-steam, so as to achieve the purpose of simplifying the operation process and improving the steam supply efficiency and economy compared with the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial steam supply, and in particular to an industrial steam supply system and a steam supply method. Background Art

[0002] At present, when using thermal power plants as steam sources to provide users with 1.0MPa~2.0MPa, 350℃~400℃ industrial steam, the commonly used solution is to extract hot resteam from the reheating hot section of the thermal power generating unit, and then spray water, reduce temperature, and reduce pressure to make its indicators meet the steam supply requirements. The main problem with this solution is that hot resteam is used entirely for steam supply, but its temperature and pressure do not meet the steam supply indicators, and additional operations such as water spraying, temperature reduction, and pressure reduction are required, which not only makes the process cumbersome and inefficient, but also leads to poor economic efficiency of steam supply.

[0003] Based on this, there is an urgent need for an industrial steam supply system and a steam supply method with a simple operation process, higher efficiency and better economy. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides an industrial steam supply system and a steam supply method, which solve the technical problems of the prior art that the operation process is complicated, the efficiency is low and the economy is poor.

[0006] (II) Technical solution

[0007] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0008] In the first aspect, an embodiment of the present invention provides an industrial steam supply system, including a thermal power generating set and a hot re-extraction unit for extracting hot re-steam from the thermal power generating set, and also including a cold re-extraction unit and a heat exchange mixing unit; the cold re-extraction unit is used to extract cold re-steam from the thermal power generating set; the cold re-extraction unit and the hot re-extraction unit are both connected to the heat exchange mixing unit through a pipeline, so that the cold re-steam delivered from the cold re-extraction unit and the hot re-steam delivered from the hot re-extraction unit are heat exchanged and remixed in the heat exchange mixing unit to form steam for supply to users. The cold re-steam delivered from the cold re-extraction unit and the hot re-steam delivered from the hot re-extraction unit enter the heat exchange mixing unit, and then form steam for supply to users through processes such as heat exchange and re-mixing. This avoids the need for additional operations such as direct water spraying, temperature reduction, and pressure reduction on the hot re-steam in the previous steam supply process.

[0009] Optionally, the heat exchange mixing unit includes a steam-steam heat exchanger and a hot and cold remixing steam header; the cold steam input port of the steam-steam heat exchanger is connected to the cold reextraction unit through a pipeline, and the cold steam output port is connected to the hot and cold remixing steam header through a pipeline; the hot steam input port of the steam-steam heat exchanger is connected to the hot reextraction unit through a pipeline, and the hot steam output port is connected to the hot and cold remixing steam header through a pipeline. The hot resteam and the cold resteam are respectively input into the steam-steam heat exchanger through the hot steam input port and the cold steam input port for heat exchange, and after heat exchange, they are jointly input into the hot and cold remixing steam header for remixing, so as to prevent the direct mixing of the hot resteam and the cold resteam from generating large thermal stress and affecting the safe operation of the equipment.

[0010] Optionally, the hot re-extraction unit includes a hot re-extraction pipeline, a steam inlet end of the hot re-extraction pipeline is connected to the reheating hot section of the thermal power generating set, and a steam outlet end is connected to the steam-steam heat exchanger.

[0011] Optionally, the hot re-extraction steam pipeline is multiple; the hot re-extraction steam unit also includes a hot remixing steam manifold; the multiple hot re-extraction steam pipelines are all connected to the steam-steam heat exchanger through the hot remixing steam manifold.

[0012] Optionally, the steam outlet ends of the multiple hot re-extraction steam pipelines are connected to the hot re-mixing steam inlet of the hot re-mixing steam header; the hot re-mixing steam outlet of the hot re-mixing steam header is connected to the steam-steam heat exchanger. The multiple hot re-steams are mixed before entering the steam-steam heat exchanger, which can ensure that the temperature and pressure of the hot re-steam entering the steam-steam heat exchanger are basically consistent, so as to facilitate the efficiency of subsequent heat exchange, re-mixing, etc.

[0013] Optionally, the cold re-extraction unit includes a cold re-extraction pipeline, a steam inlet end of the cold re-extraction pipeline is connected to the cold re-extraction section of the thermal power generator set, and a steam outlet end is connected to the steam-steam heat exchanger.

[0014] Optionally, the cold re-extraction steam pipeline is multi-channel; the cold re-extraction steam unit further includes a cold re-mixing steam header; the multi-channel cold re-extraction steam pipelines are connected to the steam-steam heat exchanger through the cold re-mixing steam header. The multi-channel cold re-extraction steam is mixed before entering the steam-steam heat exchanger, which can ensure that the temperature and pressure of the cold re-extraction steam entering the steam-steam heat exchanger are basically consistent, so as to facilitate the efficiency of subsequent heat exchange, re-mixing, etc.

[0015] Optionally, the steam outlet ends of the multiple cold re-extraction steam pipelines are connected to the cold re-mixing steam inlet of the cold re-mixing steam header; and the cold re-mixing steam outlet of the cold re-mixing steam header is connected to the steam-steam heat exchanger.

[0016] On the other hand, an embodiment of the present invention provides an industrial steam supply method, the method comprising the following steps:

[0017] S1, extracting hot resteam from the reheating hot section of the thermal power generating unit by using the hot resteam extraction unit; at the same time, extracting cold resteam from the cold resteam extraction section of the thermal power generating unit by using the cold resteam extraction unit;

[0018] S2. Exchanging heat and remixing the hot resteam with the cold resteam in a heat exchanging and mixing unit to form steam for supply to users.

[0019] Optionally, in step S2, the hot resteam and the cold resteam entering the heat exchange mixing unit undergo steam-steam heat exchange to form output hot resteam and output cold resteam after heat exchange, respectively. The output hot resteam and the output cold resteam are mixed again to form steam supplied to users.

[0020] (III) Beneficial effects

[0021] The beneficial effects of the present invention are as follows: the industrial steam supply system and steam supply method of the present invention adopts a cold and hot re-steam combined steam supply method. Specifically, the cold re-steam in the thermal power generating unit is extracted to exchange heat with the hot re-steam in a steam-steam heat exchanger, and the hot re-steam heats the cold re-steam to an appropriate temperature in the steam-steam heat exchanger. During this process, the temperature of the hot re-steam is also reduced to an appropriate temperature. Then, the two steams are pressure-regulated, mixed, and supplied to form steam supplied to users.

[0022] By adopting the scheme of the present invention, under the condition of the same steam supply, the ratio of cold re-steam can be increased (the extraction volume of cold and hot re-steam is about 3:1 compared with the previous extraction volume), thereby achieving the purpose of improving the economic efficiency of steam supply. Compared with the scheme of directly using hot re-extraction steam and spraying water to reduce temperature and pressure in the prior art, the coal consumption of power generation can be reduced by 1.44g / kWh.

[0023] In addition, under normal circumstances, the temperature difference between cold re-steam and hot re-steam can reach 240°C. When the two are directly mixed, a large thermal stress will be generated on the mixing steam header, greatly reducing the safety of equipment operation. The present invention uses a steam-steam heat exchanger to avoid this problem and improve the reliability of system equipment operation.

[0024] In summary, the present invention uses cold resteam in the thermal power generating set to exchange heat with and mix hot resteam, thereby achieving the purpose of simplifying the operation process and improving the steam supply efficiency and economy compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of Example 1 of the industrial steam supply system and steam supply method of the present invention.

[0026] Figure 2 It is a schematic structural diagram of a steam-steam heat exchanger in Example 1 of an industrial steam supply system and a steam supply method of the present invention;

[0027] Figure 3 It is a schematic diagram of the hot remixing steam header structure of Example 1 of the industrial steam supply system and steam supply method of the present invention;

[0028] Figure 4 The cold remixing steam header of Example 1 of the industrial steam supply system and steam supply method of the present invention;

[0029] Figure 5 It is a schematic diagram of the structure of the cold and hot remixing steam header of Example 1 of the industrial steam supply system and steam supply method of the present invention;

[0030] Figure 6 This is a hot resteam heat exchange path diagram of Example 1 of the industrial steam supply system and steam supply method of the present invention.

[0031] [Description of Reference Numerals]

[0032] 1: Hot re-extraction steam pipeline;

[0033] 2: Hot remix steam header;

[0034] 21: hot remixing chamber;

[0035] 22: hot remix steam inlet;

[0036] 23: hot remix steam outlet;

[0037] 231: The first steam pipeline;

[0038] 24: spare hot remix steam outlet;

[0039] 241: Fifth steam pipeline;

[0040] 3: Cold re-extraction steam pipeline;

[0041] 4: Cold remixing steam header;

[0042] 41: cold remixing cavity;

[0043] 42: cold remixed into the steam port;

[0044] 43: cold remix outlet;

[0045] 431: Second steam pipeline;

[0046] 5: Steam-steam heat exchanger;

[0047] 51: cold steam input port;

[0048] 52: cold steam outlet;

[0049] 521: The third steam pipeline;

[0050] 53: hot steam outlet;

[0051] 531: Fourth steam pipeline;

[0052] 54: housing;

[0053] 541: separator;

[0054] 542: first inner cavity;

[0055] 543: Second inner cavity;

[0056] 544: gap;

[0057] 545: coil;

[0058] 546: Extended range partition;

[0059] 5461: front range extender partition;

[0060] 5462: rear range extender partition;

[0061] 5463: front steam flow clearance;

[0062] 5464: rear steam flow clearance;

[0063] 55: hot steam input port;

[0064] 6: Cold and hot remixing steam header;

[0065] 61: hot and cold remixing cavity;

[0066] 62: hot steam input port after heat exchange;

[0067] 63: Cold steam input port after heat exchange;

[0068] 64: cold and hot remix output port;

[0069] 65: Mixed hot steam input port

[0070] 7: Temperature and pressure reducer

[0071] A: Hot re-extraction unit;

[0072] B: Cold re-extraction unit

[0073] C: Heat exchange mixing unit. DETAILED DESCRIPTION

[0074] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below in conjunction with the accompanying drawings through specific embodiments. Figure 2 The orientation is used as a reference.

[0075] The industrial steam supply system and steam supply method proposed in the embodiments of the present invention aim to solve the technical problems existing in the prior art, namely, the complicated operation process, low efficiency and poor economy. It includes a thermal power generating set and a hot re-extraction unit for extracting hot re-steam from the thermal power generating set, and also includes a cold re-extraction unit and a heat exchange mixing unit. The cold re-extraction unit is used to extract cold re-steam from the thermal power generating set. The cold re-extraction unit and the hot re-extraction unit are both connected to the heat exchange mixing unit through pipelines, so that the cold re-steam transported from the cold re-extraction unit and the hot re-steam transported from the hot re-extraction unit are heat exchanged and remixed in the heat exchange mixing unit to form steam supplied to the user. It uses the cold re-steam in the thermal power generating set to exchange heat and mix the hot re-steam, which achieves the purpose of simplifying the operation process and improving the steam supply efficiency and economy compared with the prior art.

[0076] In order to better understand the above technical solution, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0077] Embodiment 1:

[0078] Reference Figure 1 The present invention provides an industrial steam supply system, including a thermal power generating set and a hot re-extraction unit A, wherein the hot re-extraction unit A is connected to the reheating hot section of the thermal power generating set and is used to extract hot re-steam from the reheating hot section of the thermal power generating set. It also includes a cold re-extraction unit B and a heat exchange mixing unit C. The cold re-extraction unit B is connected to the cold re-extraction section of the thermal power generating set and is used to extract cold re-steam from the thermal power generating set. Both the cold re-extraction unit B and the hot re-extraction unit A are connected to the heat exchange mixing unit C through pipelines. The cold re-steam transported from the cold re-extraction unit B and the hot re-steam transported from the hot re-extraction unit A enter the heat exchange mixing unit C, and then form steam supplied to users through heat exchange, re-mixing and other processes. This avoids the need for additional direct water spraying, temperature reduction, pressure reduction and other operations on the hot re-steam in the previous steam supply process. It only needs to be in the heat exchange mixing unit C, so that the hot re-steam and the cold re-steam are heat-exchanged and re-mixed, and then form steam that meets the requirements and is provided to users.

[0079] Further, the heat exchange mixing unit C includes a steam-steam heat exchanger 5 and a cold and hot remixing steam header 6. The cold steam input port 51 of the steam-steam heat exchanger 5 is connected to the cold reextraction steam unit B through the second steam transmission pipeline 431, and the cold steam output port 52 is connected to the cold and hot remixing steam header 6 through the third steam transmission pipeline 521. The hot steam input port 55 of the steam-steam heat exchanger 5 is connected to the hot reextraction steam unit A through the first steam transmission pipeline 231, and the hot steam output port 53 is connected to the cold and hot remixing steam header 6 through the fourth steam transmission pipeline 531. The hot resteam and the cold resteam are respectively input into the steam-steam heat exchanger 5 through the hot steam input port 55 and the cold steam input port 51 for heat exchange, and after heat exchange, they are jointly input into the cold and hot remixing steam header 6 for remixing, so as to prevent the direct mixing of the hot resteam and the cold resteam from generating large thermal stress and affecting the safe operation of the equipment. The third steam transmission pipeline 521 and the fourth steam transmission pipeline 531 may be provided with pressure regulating valves for pressure regulation.

[0080] Furthermore, the hot re-extraction unit A comprises a hot re-extraction pipeline 1, the steam inlet end of the hot re-extraction pipeline 1 is connected to the reheating hot section of the thermal power generator set, and the steam outlet end is connected to the steam-steam heat exchanger 5 of the heat exchange mixing unit C.

[0081] Here, if there is only one hot re-extraction steam pipeline 1 , its steam outlet end can be directly connected to the hot steam input port 55 of the steam-steam heat exchanger 5 through the first steam transmission pipeline 231 .

[0082] The hot re-extraction steam pipeline 1 can also be multiple. For example, it can be two, etc. The specific number can be selected according to the actual situation. At this time, the hot re-extraction steam unit A also includes a hot re-mixing steam header 2. The function of the hot re-mixing steam header 2 is mainly to mix the hot re-steam from multiple routes and output them in a centralized manner. Figure 3 The hot remixing steam manifold 2 includes a hot remixing chamber 21, and a plurality of hot remixing steam inlets 22 communicating with the hot remixing chamber 21 are provided on one side outer wall of the hot remixing chamber 21. A hot remixing steam outlet 23 communicating with the hot remixing chamber 21 is provided on the other side outer wall of the hot remixing chamber 21. The steam outlet end of each hot remixing steam extraction pipeline 1 is respectively connected to a hot remixing steam inlet 22, so that each hot remixing steam enters the hot remixing chamber 21 through the hot remixing steam inlet 22, mixes, and then is output from the hot remixing steam outlet 23. The hot remixing steam outlet 23 is connected to the hot steam input port 55 of the steam-steam heat exchanger 5 in the heat exchange mixing unit C through the first steam transmission pipeline 231. The hot re-steam mixing manifold 2 mixes the hot re-steam output from the multiple hot re-extraction steam pipelines 1 and then outputs them in a centralized manner, which, on the one hand, avoids excessive use of output pipelines, reduces efficiency and increases costs; on the other hand, the multiple hot re-steams are mixed before entering the steam-steam heat exchanger 5, which can ensure that the temperature and pressure of the hot re-steam entering the steam-steam heat exchanger 5 are basically consistent, so as to facilitate the efficiency of subsequent heat exchange, re-mixing, etc. A valve can be set on the first steam transmission pipeline 231 to control the steam transmission volume.

[0083] Furthermore, the cold re-extraction unit B includes a cold re-extraction pipeline 3, the steam inlet end of the cold re-extraction pipeline 3 is connected to the cold re-extraction section of the thermal power generator set, and the steam outlet end is connected to the steam-steam heat exchanger 5 in the heat exchange mixing unit C.

[0084] The cold re-extraction steam pipeline 3 can be one line, in which case the steam outlet of the cold re-extraction steam pipeline 3 is directly connected to the cold steam input port 51 of the steam-steam heat exchanger 5 through the second steam delivery pipeline 431. A valve can be provided on the second steam delivery pipeline 431 to control the steam delivery amount.

[0085] Preferably, the cold re-extraction steam pipeline 3 can also be multiple, and in this case, the cold re-extraction steam unit B also includes a cold re-mixing steam header 4. Figure 4 The cold remixing steam header 4 includes a cold remixing chamber 41, and a plurality of cold remixing steam inlets 42 connected to the cold remixing chamber 41 are arranged on one side outer wall of the cold remixing chamber 41, and a cold remixing steam outlet 43 is arranged on the other side outer wall of the cold remixing chamber 41. The steam outlet end of each cold remixing steam extraction pipeline 3 is respectively connected to a cold remixing steam inlet 42, so that the cold remixing steam of multiple routes is mixed in the cold remixing chamber 41 and then output through the cold remixing steam outlet 43, and the cold remixing steam outlet 43 is connected to the cold steam input port 51 of the steam-steam heat exchanger 5 through the second steam transmission pipeline 431.

[0086] Reference Figure 1 , 2 5, further with respect to the above heat exchange mixing unit C, as a preferred solution, the steam-steam heat exchanger 5 can be of the following structure: the steam-steam heat exchanger 5 includes a shell 54, the inner cavity of the shell 54 is provided with a partition plate 541, and the partition plate 541 divides the inner cavity of the shell 54 into a first inner cavity 542 and a second inner cavity 543. Figure 2 Taking the horizontal housing 54 as an example, the so-called horizontal arrangement is as shown in the figure, and the length in the horizontal direction, that is, the left-right direction, is longer; while the vertical arrangement is to Figure 2 The picture in the figure can be rotated 90° clockwise. In the horizontal shell 54, the partition plate 541 is also horizontal, so that the first inner cavity 542 is located above the second inner cavity 543. One end of the partition plate 541 is fixedly connected to the inner wall of one side of the shell 54, and a gap 544 is formed between the other end of the partition plate 541 and the inner wall of the other side of the shell 54. The first inner cavity 542 and the second inner cavity 543 are connected through the gap 544, which is equivalent to dividing the inner cavity of the shell 54 into a U-shaped cavity. A continuous coil 545 is arranged in the first inner cavity 542 and the second inner cavity 543. The coil 545 can be laid in a continuous "S" shape. The so-called continuous "S" shape laying means that the coil 545 extends from the first inner cavity 542 to the second inner cavity 543, and multiple transverse tubes are arranged in the first inner cavity 542 and the second inner cavity 543. The multiple transverse tubes can be arranged in parallel, and the two adjacent transverse tubes are connected end to end to form a U-shaped cavity. Figure 2 The "S" shape shown. The end-to-end connection described here, taking the arrangement of three rows of transverse tubes as an example, the right end of the top transverse tube, i.e. the tail end, is connected to the right end, i.e. the head end, of the middle transverse tube, and the left end, i.e. the tail end, of the middle transverse tube is connected to the left end, i.e. the head end, of the bottom transverse tube, and so on, the coil 545 extends from the first inner cavity 542 to the second inner cavity 543. The form of the coil 545 in the second inner cavity 543 is the same as that of the coil 545 in the first inner cavity 542. The bottom transverse tube in the first inner cavity 542 is connected to the top transverse tube in the second inner cavity 543. One end of the coil 545 is connected to the cold steam input port 51, which is located at the top or side wall of the first inner cavity 542, and the cold steam input port 51 is connected to the cold re-extraction unit B through the second steam transmission pipeline 431. That is, if the cold re-extraction steam pipeline 3 in the cold re-extraction steam unit B is one-way, the cold steam input port 51 is directly connected to the cold re-extraction steam pipeline 3 through the second steam transmission pipeline 431; if the cold re-extraction steam pipeline 3 in the cold re-extraction steam unit B is multi-way, the cold steam input port 51 is connected to the cold re-mixing steam outlet 43 of the cold re-mixing steam header 4 through the second steam transmission pipeline 431. The other end of the coil 545 is connected to the cold steam output port 52. The cold steam output port 52 is located at the bottom or side wall of the second inner cavity 543. The cold steam output port 52 is connected to the cold and hot re-mixing steam header 6 through the third steam transmission pipeline 521. The cold re-steam output from the cold re-extraction unit B enters the coil 545 through the cold steam input port 51, and is transported to the cold steam output port 52 in the coil 545 in an S-shaped path, and then enters the cold and hot re-mixing steam header 6 through the third steam transmission pipeline 521. The "S"-shaped coil 545 is mainly used to extend the heat exchange process of the cold re-steam. Figure 2 As shown by the straight arrow in the figure, the heat exchange time can be extended so that the cold re-steam and the hot re-steam can fully exchange heat in the shell 54. Alternatively, the coil 545 can also be laid in the following form: a transverse tube is arranged in each of the first inner cavity 542 and the second inner cavity 543, the left end of the transverse tube in the first inner cavity 542 is connected to the cold steam input port 51, and the right end is connected to the right end of the transverse tube in the second inner cavity 543, so that the two transverse tubes form a "U"-shaped structure, and the left end of the transverse tube in the second inner cavity 543 is connected to the cold steam output port 52. The "U"-shaped coil 545 also increases the cold re-steam heat exchange process to a certain extent and extends the heat exchange time.

[0087] Further preferably, a hot steam input port 55 is provided on the side wall or the top of the first inner cavity 542, and the hot steam input port 55 is connected to the first inner cavity 542. The inner cavity of the shell 54 can also be provided with an extended range baffle 546, and the extended range baffle 546 is perpendicular to the partition plate 541. The so-called extended range baffle means that its function is to extend the travel of the hot resteam in the shell 54. The extended range baffle 546 includes a front extended range baffle 5461 and a rear extended range baffle 5462. Both the front extended range baffle 5461 and the rear extended range baffle 5462 can be provided in multiples. In the first inner cavity 542, the top and both sides of the front extended range baffle 5461 are connected to the inner wall of the first inner cavity 542, and a front steam flow gap 5463 is formed between the bottom of the front extended range baffle 5461 and the upper surface of the partition plate 541. The bottom of the rear range extending baffle 5462 is fixedly connected to the partition plate 541, and the two sides of the rear range extending baffle 5462 are fixedly connected to the inner walls of the two sides of the first inner cavity 542. A rear steam flow gap 5464 is formed between the top of the rear range extending baffle 5462 and the top inner wall of the first inner cavity 542. The front range extending baffle 5461 and the rear range extending baffle 5462 are arranged alternately, so that the hot resteam enters the first inner cavity 542 from the hot steam input port 55, and then passes through the front steam flow gap 5463, the rear steam flow gap 5464, and then passes through the front steam flow gap 5463, the rear steam flow gap 5464, and so on, until it passes through the gap 544 and enters the second inner cavity 543. In the second inner cavity 543, the bottom and both sides of the front range-extending baffle 5461 are connected to the inner wall of the second inner cavity 543, and a front steam flow gap 5463 is formed between the top of the front range-extending baffle 5461 and the lower surface of the partition plate 541. The top of the rear range-extending baffle 5462 is fixedly connected to the partition plate 541, and both sides of the rear range-extending baffle 5462 are fixedly connected to the inner walls of both sides of the second inner cavity 543, and a rear steam flow gap 5464 is formed between the bottom of the rear range-extending baffle 5462 and the bottom inner wall of the second inner cavity 543. The front range extender baffle 5461 and the rear range extender baffle 5462 in the second inner cavity 543 are also arranged alternately, so that the hot resteam from the first inner cavity 542 passes through the rear steam flow gap 5464 and the front steam flow gap 5463 in the second inner cavity 543, and then passes through the rear steam flow gap 5464, the front steam flow gap 5463, and so on, until it is discharged from the hot steam output port 53 on the side wall or bottom of the second inner cavity 543, and then transported to the hot and cold remixing steam manifold 6 through the fourth steam transmission pipeline 531. After the hot resteam enters the first inner cavity 542 from the hot steam input port 55 and passes through multiple front steam flow gaps 5463 and rear steam flow gaps 5464, it is transported in the first inner cavity 542 in an "S" path, as shown in FIG. Figure 2 The hot resteam then passes through the gap 544 and enters the second inner chamber 543, where it is still transported in an "S"-shaped path until it is discharged from the hot steam outlet 53. The overall path of the hot resteam in the shell 54 is shown in FIG. Figure 6As shown by the middle dotted line. The exhausted hot resteam enters the hot and cold remixing steam manifold 6 through the fourth steam transmission pipeline 531. The "S"-shaped path for transporting hot resteam is also to increase the length of the hot resteam transmission path and further enhance the heat exchange effect. The hot steam input port 55 is connected to the hot re-extraction unit A through the first steam transmission pipeline 231. That is, if the hot re-extraction pipeline 1 in the re-extraction unit A is one-way, the hot steam input port 55 is directly connected to the hot re-extraction pipeline 1 through the first steam transmission pipeline 231. If the hot re-extraction pipeline 1 in the re-extraction unit A is multiple-way, the hot steam input port 55 is connected to the hot remixing steam outlet 23 of the hot remixing steam manifold 2 through the first steam transmission pipeline 231.

[0088] Reference Figure 5 , with respect to the hot and cold remixing steam manifold 6, the hot and cold remixing steam manifold 6 comprises a hot and cold remixing chamber 61, the top of the hot and cold remixing chamber 61 is provided with a hot steam input port 62 after heat exchange and a cold steam input port 63 after heat exchange, and a hot and cold remixing output port 64 is provided at the bottom of the hot and cold remixing chamber 61. The hot steam input port 62 after heat exchange is connected to the hot steam output port 53 in the steam-steam heat exchanger 5 through the fourth steam transmission pipeline 531. The cold steam input port 63 after heat exchange is connected to the cold steam output port 52 in the steam-steam heat exchanger 5 through the third steam transmission pipeline 521. The hot and cold remixing output port 64, as the final output end, outputs the steam with suitable temperature and pressure formed after heat exchange and remixing to the user.

[0089] Embodiment 2:

[0090] The present invention also provides an industrial steam supply method, the method comprising the following steps:

[0091] S1. Use the hot re-extraction unit A to extract hot re-steam from the reheating hot section of the thermal power generating unit, that is, extract hot re-steam through the hot re-extraction pipeline 1; use the cold re-extraction unit B to extract cold re-steam from the cold re-extraction section of the thermal power generating unit, that is, extract cold re-steam using the cold re-extraction pipeline 3.

[0092] S2. In the heat exchange mixing unit C, the hot resteam and the cold resteam are exchanged and mixed by the steam-steam heat exchanger 5 and the hot-cold remixing steam header 6 to form steam supplied to the user. That is, the hot resteam and the cold resteam entering the heat exchange mixing unit C are respectively formed into the output hot resteam and the output cold resteam after heat exchange after steam-steam heat exchange, and the output hot resteam and the output cold resteam are mixed again by the hot-cold remixing steam header 6 to form steam supplied to the user.

[0093] After the hot resteam and the cold resteam are fully heat exchanged and then mixed, the cold resteam can be heated to an appropriate temperature, and the temperature of the hot resteam can be reduced to an appropriate temperature. Then the two steam streams are pressure-regulated, mixed, and then supplied. Under the same steam supply, the proportion of cold resteam can be increased, thereby achieving the purpose of improving the economic efficiency of steam supply. At the same time, heat exchange first and then mixing avoids the problem of large thermal stress caused by direct mixing between cold and hot resteams, and improves the reliability of system equipment operation.

[0094] Reference Figures 1 to 6 , the structure and use process of the present invention are further sorted out. This description is only to combine the above multiple preferred methods by way of example to facilitate a comprehensive description, but this description is not a limitation on the implementation methods of the present application. The description is as follows:

[0095] A thermal power plant generally has at least two thermal power generating units. Take two 300MW thermal power generating units as an example. The two thermal power generating units are named as Unit #1 and Unit #2. The corresponding hot re-extraction steam pipeline 1 and cold re-extraction steam pipeline 3 are also two lines. Of the two hot re-extraction steam pipelines 1, one is used to extract hot re-steam from Unit #1, and the other is used to extract hot re-steam from Unit #2. Of the two cold re-extraction steam pipelines 3, one is used to extract cold re-steam from Unit #1, and the other is used to extract cold re-steam from Unit #2.

[0096] The steam inlet ends of the two hot re-extraction steam pipelines 1 are respectively connected to the reheating hot sections of the #1 unit and the #2 unit, and the steam outlet ends are respectively connected to the two hot re-mixing steam inlets 22 of the hot re-mixing steam header 2. The hot re-mixing steam outlet 23 is connected to the hot steam input port 55 of the steam-steam heat exchanger 5 through the first steam transmission pipeline 231. The steam inlet ends of the corresponding two cold re-extraction steam pipelines 3 are respectively connected to the cold re-extraction steam sections of the #1 unit and the #2 unit, and the steam outlet ends are respectively connected to the two cold re-mixing steam inlets 42 of the cold re-mixing steam header 4, and the cold re-mixing steam outlet 43 is connected to the cold steam input port 51 of the steam-steam heat exchanger 5 through the second steam transmission pipeline 431.

[0097] The cold steam output port 52 of the steam-steam heat exchanger 5 is connected to the cold steam input port 63 of the cold and hot remixing steam header 6 through the third steam transmission pipeline 521. The hot steam output port 53 of the steam-steam heat exchanger 5 is connected to the hot steam input port 62 through the fourth steam transmission pipeline 531.

[0098] In addition, as a backup, a backup hot remix steam outlet 24 can be provided on the side wall of the hot remix steam header 2, and a mixed hot steam input port 65 can be provided on the side wall of the cold and hot remix steam header 6. The backup hot remix steam outlet 24 is connected to the mixed hot steam input port 65 through the fifth steam transmission pipeline 241. A temperature and pressure reducer 7 is provided on the fifth steam transmission pipeline 241.

[0099] Taking the average power generation load of a single thermal power generating unit as 200MW, the steam flow rate as 130t / h, the steam pressure as 1.6MPa, and the steam temperature as 350℃ as an example, the operation mode of the system is as follows: Unit #1 performs machine cooling and steam extraction through one cold steam extraction pipeline 3, extracting 50t / h of cold steam; Unit #2 performs machine cooling and steam extraction through one cold steam extraction pipeline 3, extracting 47t / h of cold steam; the two cold steams are input into the cold steam mixing box 4 and mixed to form cold steam with uniform temperature and pressure, and then enter the steam-steam heat exchanger 5 through the second steam transmission pipeline 431. At the same time, hot steam is extracted through the machine heat steam extraction, and the extraction of hot steam can be selected according to needs, and can be selected from Unit #1 or Unit #2 alone, or can be selected from both Unit #1 and Unit #2. In this embodiment, 33 t / h of reheated steam is extracted and enters the hot remixing steam header 2, and then enters the steam-steam heat exchanger 5 through the first steam transmission pipeline 231 to heat the cold reheated steam. Figure 2 Taking the steam-steam heat exchanger 5 structure shown in the figure as an example, the cold re-steam output by the second steam pipeline 431 enters the coil 545 through the cold steam input port 51 to form an S-shaped transmission path. At the same time, the hot re-steam output by the first steam pipeline 231 enters the first inner cavity 542 through the hot steam input port 55, and then passes through a plurality of front steam flow gaps 5463, rear steam flow gaps 5464, etc. in sequence, and then enters the second inner cavity 543, and then passes through a plurality of rear steam flow gaps 5464, front steam flow gaps 5463, etc. in sequence, forming an overall S-shaped transmission path, see for details. Figure 6 The hot resteam heat exchange path diagram is shown in the figure, and the dotted line in the figure shows the hot resteam transmission path. The hot resteam and the cold resteam fully exchange heat in the first inner cavity 542 and the second inner cavity 543, the cold resteam is heated up, and the hot resteam is cooled down. After the heat exchange is completed, the hot resteam is transported to the hot and cold remixing steam header 6 through the fourth steam transmission pipeline 531, and the cold resteam is transported to the hot and cold remixing steam header 6 through the third steam transmission pipeline 521. The two will enter the hot and cold remixing steam header 6 at a relatively close temperature for remixing, avoiding large thermal stress caused by excessive temperature difference, which improves the safety of equipment operation.

[0100] In addition, when a unit is shut down, a backup plan can be adopted to no longer extract cold re-steam, that is, the operating mode is to use the hot re-extraction pipeline 1 for a normally operating unit to extract 109 t / h of hot re-steam, which is then output through the fifth steam transmission pipeline 241 and is cooled and reduced in pressure by spraying water through the desuperheater and pressure reducer 7. The hot re-steam after cooling and pressure reduction is supplied to the user through the hot and cold re-mixing steam manifold 6, with a cooling water volume of 21 t / h.

[0101] In summary, the industrial steam supply system and steam supply method of the present invention effectively solve the technical problems of the prior art such as complicated operation process, low efficiency and poor economy, and are conducive to promotion and application in the field of industrial steam supply technology.

[0102] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0103] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation" and the like should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0104] In the present invention, unless otherwise clearly specified and limited, a first feature being “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature.

[0105] In the description of this specification, the description of the term "embodiment" and the like refers to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they contradict each other.

[0106] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An industrial steam supply system, comprising a thermal power generating set and a hot re-extraction unit (A) for extracting hot re-steam from the thermal power generating set, characterized in that: It also includes a cold re-extraction unit (B) and a heat exchange mixing unit (C); the cold re-extraction unit (B) is used to extract cold re-steam from the thermal power generating set; the cold re-extraction unit (B) and the hot re-extraction unit (A) are both connected to the heat exchange mixing unit (C) through pipelines, so that the cold re-steam delivered from the cold re-extraction unit (B) and the hot re-steam delivered from the hot re-extraction unit (A) are heat exchanged and re-mixed in the heat exchange mixing unit (C) to form steam supplied to users; The heat exchange mixing unit (C) comprises a steam-steam heat exchanger (5) and a cold and hot remixing steam manifold (6); the cold steam input port of the steam-steam heat exchanger (5) is connected to the cold re-extraction steam unit (B) through a pipeline, and the cold steam output port is connected to the cold and hot remixing steam manifold (6) through a pipeline; the hot steam input port of the steam-steam heat exchanger (5) is connected to the hot re-extraction steam unit (A) through a pipeline, and the hot steam output port is connected to the cold and hot remixing steam manifold (6) through a pipeline.

2. The industrial steam supply system according to claim 1, characterized in that: The hot re-extraction unit (A) comprises a hot re-extraction pipeline (1), the steam inlet end of the hot re-extraction pipeline (1) is connected to the reheating hot section of the thermal power generating set, and the steam outlet end is connected to the steam-steam heat exchanger (5).

3. The industrial steam supply system according to claim 2, characterized in that: The hot re-extraction steam pipeline (1) is multi-channel; the hot re-extraction steam unit (A) also includes a hot re-mixing steam header (2); the multi-channel hot re-extraction steam pipeline (1) is connected to the steam-steam heat exchanger (5) through the hot re-mixing steam header (2).

4. The industrial steam supply system according to claim 3, characterized in that: The steam outlet ends of the multiple hot re-extraction steam pipelines (1) are connected to the hot re-mixing steam inlet of the hot re-mixing steam header (2); and the hot re-mixing steam outlet of the hot re-mixing steam header (2) is connected to the steam-steam heat exchanger (5).

5. The industrial steam supply system according to claim 1, characterized in that: The cold re-extraction unit (B) comprises a cold re-extraction pipeline (3), the steam inlet end of the cold re-extraction pipeline (3) is connected to the cold re-extraction section of the thermal power generating set, and the steam outlet end is connected to the steam-steam heat exchanger (5).

6. The industrial steam supply system according to claim 5, characterized in that: The cold re-extraction steam pipeline (3) is multi-channel; the cold re-extraction steam unit (B) further comprises a cold re-mixing steam header (4); the multi-channel cold re-extraction steam pipeline (3) is connected to the steam-steam heat exchanger (5) through the cold re-mixing steam header (4).

7. The industrial steam supply system according to claim 6, characterized in that: The steam outlet ends of the multiple cold re-extraction steam pipelines (3) are connected to the cold re-mixing steam inlet of the cold re-mixing steam header (4); and the cold re-mixing steam outlet of the cold re-mixing steam header (4) is connected to the steam-steam heat exchanger (5).

8. An industrial steam supply method, characterized in that: The method is carried out using the industrial steam supply system as described in any one of claims 1 to 7, and the steps are as follows: S1, extracting hot resteam from the reheating hot section of the thermal power generating unit by using the hot resteam extraction unit (A); at the same time, extracting cold resteam from the cold resteam extraction section of the thermal power generating unit by using the cold resteam extraction unit (B); S2. The hot resteam and the cold resteam are subjected to heat exchange and remixing in a heat exchange and mixing unit (C) to form steam for supply to users.

9. The industrial steam supply method according to claim 8, characterized in that: In step S2, the hot resteam and the cold resteam entering the heat exchange mixing unit (C) are subjected to steam-steam heat exchange to form output hot resteam and output cold resteam after heat exchange, respectively. The output hot resteam and the output cold resteam are mixed again to form steam supplied to users.

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