Steam multi-stage utilization system, steam multi-stage utilization method and molding equipment

Abstract

The invention relates to a steam multi-stage utilization system, a steam multi-stage utilization method and molding equipment, and relates to the technical field of paper pulp molding. The steam multi-stage utilization system comprises a steam generation device, a multi-stage heat exchange unit and a gas-liquid separation unit. The steam generating device is used for generating primary steam; the multi-stage heat exchange unit is connected with the steam generation device and used for receiving the primary steam for heat exchange and converting the primary steam into primary condensate; the gas-liquid separation unit is connected with the multi-stage heat exchange unit and the steam generation device and used for receiving the primary condensate and the primary steam to obtain secondary steam and conveying the secondary steam to the multi-stage heat exchange unit for heat exchange so that the secondary steam can be converted into secondary condensate. According to the technical scheme disclosed by the invention, the steam condensate water in paper pulp molding drying can be recycled, so that the energy consumption of equipment is reduced, and the steam quality and the heat exchange efficiency are also improved.

Description

Technical Field

[0001] The invention relates to the technical field of pulp molding, and in particular to a multi-stage steam utilization system, a multi-stage steam utilization method and molding equipment. Background Art

[0002] Pulp molding is a three-dimensional papermaking technology that uses pulp as raw material. It is generally obtained after pulp preparation, molding, drying, and shaping. It has the advantages of being biodegradable, recyclable, and green. At present, pulp molding drying is increasingly using steam heating. Steam is passed into the mold, and the latent heat of steam phase change is used to transfer heat to the pulp molding, thereby evaporating water and achieving pulp molding drying. However, the existing molding equipment has two ways of dealing with steam condensate during pulp molding drying: one is to directly discharge it, which causes energy waste and high equipment energy consumption; the other is to directly reuse it after gas-liquid separation, but the steam quality is greatly reduced, resulting in reduced heat exchange efficiency. Summary of the invention

[0003] The embodiments of the present invention provide a steam multi-stage utilization system, a steam multi-stage utilization method and a molding device, which can recycle the steam condensed water in pulp molding and drying, which not only reduces the energy consumption of the equipment, but also improves the steam quality and heat exchange efficiency.

[0004] In a first aspect, an embodiment of the present invention provides a multi-stage steam utilization system, comprising:

[0005] A steam generating device for generating primary steam;

[0006] a multi-stage heat exchange unit, connected to the steam generating device, configured to receive the primary steam for heat exchange and convert the primary steam into primary condensate; and

[0007] The gas-liquid separation unit is connected to the multi-stage heat exchange unit and the steam generating device, and is used to receive the primary condensate and the primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange so that the secondary steam is converted into secondary condensate.

[0008] In one embodiment, the multi-stage heat exchange unit comprises:

[0009] a primary heat exchange unit, wherein the inlet and the outlet of the primary heat exchange unit are respectively connected to the steam generating device and the gas-liquid separation unit, and the primary heat exchange unit is used to receive the primary steam for a heat exchange and convert the primary steam into a primary condensate; and

[0010] A secondary heat exchange unit, wherein the inlet and the outlet of the secondary heat exchange unit are respectively connected to the gas-liquid separation unit and the steam generating device, and the secondary heat exchange unit is used to receive the secondary steam for secondary heat exchange and convert the secondary steam into secondary condensate, and the secondary condensate is injected into the steam generating device.

[0011] In one embodiment, the gas-liquid separation unit comprises:

[0012] A plurality of gas-liquid separation tanks, each of which is provided with a first inlet pipe and a second inlet pipe;

[0013] A first delivery pipe, one end of which is connected to the primary heat exchange unit and the other end of which is connected to the first inlet pipe;

[0014] a second delivery pipe, one end of which is connected to the steam generating device and the other end of which is connected to the second inlet pipe; and

[0015] The steam trap is arranged on the first delivery pipe.

[0016] In one embodiment, a steam outlet pipe is provided on the gas-liquid separation tank, wherein the gas-liquid separation unit further includes a third delivery pipe, one end of the third delivery pipe is connected to the steam outlet pipe and the other end is connected to the secondary heat exchange unit.

[0017] In one embodiment, the gas-liquid separation unit further comprises:

[0018] A first valve is disposed on the first inlet pipe to control the opening and closing of the first inlet pipe;

[0019] a second valve, disposed on the second inlet pipe, to control the opening and closing of the second inlet pipe; and

[0020] The third valve is arranged on the steam outlet pipe to control the opening and closing of the steam outlet pipe.

[0021] In a second aspect, an embodiment of the present invention provides a multi-stage steam utilization method, which is applied to the multi-stage steam utilization system as described above, comprising:

[0022] generating primary steam by the steam generating device;

[0023] transporting the primary steam to the multi-stage heat exchange unit for heat exchange, and converting the primary steam into primary condensate;

[0024] injecting the primary condensate and the primary steam into the gas-liquid separation unit in sequence to obtain secondary steam;

[0025] The secondary steam is transported to the multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into secondary condensate.

[0026] In one embodiment, the multi-stage heat exchange unit includes a primary heat exchange unit and a secondary heat exchange unit;

[0027] The delivering the primary steam to the multi-stage heat exchange unit for heat exchange and converting the primary steam into primary condensate is specifically: delivering the primary steam to a first-stage heat exchange unit for one heat exchange and converting the primary steam into primary condensate;

[0028] The delivering the secondary steam to the multi-stage heat exchange unit for heat exchange and converting the secondary steam into secondary condensate is specifically: delivering the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate.

[0029] In one embodiment, the step of sequentially injecting the primary condensate and the primary steam into the gas-liquid separation unit to obtain secondary steam comprises:

[0030] Injecting the primary condensate into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a first preset pressure;

[0031] The primary steam is injected into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a second preset pressure, thereby obtaining the secondary steam.

[0032] In one embodiment, the gas-liquid separation unit comprises a plurality of gas-liquid separation tanks;

[0033] The step of injecting the primary condensate into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a first preset pressure comprises: injecting the primary condensate into a plurality of gas-liquid separation tanks in sequence until the real-time pressure in the plurality of gas-liquid separation tanks reaches the first preset pressure in sequence;

[0034] The step of injecting the primary steam into the gas-liquid separation unit until the real-time pressure inside the gas-liquid separation unit reaches a second preset pressure to obtain the secondary steam comprises: injecting the primary steam into a plurality of gas-liquid separation tanks in sequence until the real-time pressure inside the plurality of gas-liquid separation tanks reaches a second preset pressure in sequence to obtain the secondary steam in sequence.

[0035] In one embodiment, the step of injecting the primary steam into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a second preset pressure to obtain the secondary steam further comprises:

[0036] Obtaining the liquid level of the primary condensate in the gas-liquid separation unit;

[0037] If the liquid level height is less than a preset liquid level threshold, the injection of the primary steam into the gas-liquid separation unit is stopped.

[0038] In one embodiment, the step of transporting the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate further comprises:

[0039] The secondary condensate is injected into the steam generating device.

[0040] In one embodiment, the step of transporting the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate further comprises:

[0041] Obtaining the real-time pressure in the gas-liquid separation unit;

[0042] If the real-time pressure is less than the third preset pressure, the delivery of the secondary steam to the secondary heat exchange unit is stopped.

[0043] In a third aspect, an embodiment of the present invention provides a molding device, comprising the multi-stage steam utilization system as described above.

[0044] Compared with the prior art, the advantages of the embodiments of the present invention are that, by setting up a multi-stage heat exchange unit to receive primary steam and secondary steam respectively, the graded utilization of steam is realized, ensuring that steam of different qualities can be used. By using the primary condensate generated by condensation after heat exchange in the multi-stage heat exchange unit as one of the sources of secondary steam, the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam temperature reduction is transferred to the primary condensate, and the primary condensate is boiled again when it encounters heat and converted into steam and mixed with the primary steam to form secondary steam for use by the multi-stage heat exchange unit, thereby realizing the effective utilization of the primary condensate, avoiding the waste of heat in the primary condensate, reducing the discharge and loss of heat, reducing the consumption of saturated steam, improving the steam quality and heat exchange efficiency, and greatly reducing the production cost of pulp molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0046] Figure 1 is a structural schematic diagram of a steam multi-stage utilization system provided by an embodiment of the present invention;

[0047] Figure 2 It is a flow chart of a multi-stage steam utilization method provided by another embodiment of the present invention.

[0048] Reference numerals:

[0049] 10. Steam generating device;

[0050] 20. Primary heat exchange unit;

[0051] 30, gas-liquid separation unit; 310, gas-liquid separation tank; 3101, first inlet pipe; 3102, second inlet pipe; 3103, steam outlet pipe; 320, first delivery pipe; 330, second delivery pipe; 340, third delivery pipe; 350, first valve; 360, second valve; 370, third valve;

[0052] 40. Secondary heat exchange unit;

[0053] 50. Steam trap;

[0054] 60. Water supply tank. DETAILED DESCRIPTION

[0055] The present invention will be further described below in conjunction with the accompanying drawings.

[0056] Pulp molding is a three-dimensional papermaking technology that uses pulp as raw material. It is generally obtained after pulp preparation, molding, drying, and shaping. It has the advantages of being biodegradable, recyclable, and green and environmentally friendly. In the production of pulp molding, its raw material is generally a pulp fiber suspension with a concentration of less than 1%, and the finished pulp molding generally needs to have a dryness of more than 90%. The moisture removed from each kilogram of pulp molding product through hot pressing and drying is about 3-5kg.

[0057] At present, the main methods of pulp molding drying include electric heating, thermal oil heating and steam heating. Steam heating is increasingly favored by pulp molding manufacturers due to its many advantages such as high efficiency and low cost. Steam heating for pulp molding is to pass steam into the mold, use the latent heat of steam phase change, transfer heat to the pulp molding, thereby evaporating water and achieving pulp molding drying. However, the existing molding equipment has two ways of dealing with steam condensate during pulp molding drying: one is to directly discharge it, resulting in energy waste and high equipment energy consumption; the other is to directly reuse it after gas-liquid separation, but the steam quality is greatly reduced, resulting in reduced heat exchange efficiency.

[0058] Embodiment 1

[0059] like Figure 1As shown, in order to solve the above technical problems, an embodiment of the present invention provides a multi-stage steam utilization system, including a steam generating device 10, a multi-stage heat exchange unit and a gas-liquid separation unit 30; the steam generating device 10 is used to generate primary steam; the multi-stage heat exchange unit is connected to the steam generating device 10, and is used to receive primary steam for heat exchange, and convert the primary steam into primary condensate; the gas-liquid separation unit 30 is connected to the multi-stage heat exchange unit and the steam generating device 10, and is used to receive primary condensate and primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange to convert the secondary steam into secondary condensate.

[0060] As can be seen from the above, by setting up a multi-stage heat exchange unit to receive primary steam and secondary steam respectively, the graded utilization of steam is realized, ensuring that steam of different qualities can be used. By using the primary condensate generated by condensation after heat exchange in the multi-stage heat exchange unit as one of the sources of secondary steam, the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit 30, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam temperature reduction is transferred to the primary condensate, and the primary condensate is boiled again when it encounters heat and converted into steam and mixed with the primary steam to form secondary steam for use by the multi-stage heat exchange unit, thereby realizing the effective utilization of the primary condensate, avoiding the waste of heat in the primary condensate, reducing the discharge and loss of heat, reducing the consumption of saturated steam, improving the steam quality and heat exchange efficiency, and greatly reducing the production cost of pulp molding.

[0061] It should be noted that the steam generating device 10 includes but is not limited to a boiler; the primary steam may be saturated steam generated by a boiler or waste heat steam from a power plant.

[0062] It should also be noted that the multi-stage heat exchange unit includes multiple heat exchange units. Since the quality of steam is different when the heat exchange unit reuses the steam, in order to distinguish the multiple heat exchange units, the multiple heat exchange units can be named in sequence according to the first level, second level, third level, fourth level, etc., a first-level heat exchange unit, a second-level heat exchange unit, a third-level heat exchange unit, a fourth-level heat exchange unit, etc.; it can be understood that the first-level heat exchange unit and the second-level heat exchange unit are adjacent heat exchange units, and the first-level heat exchange unit is the upper-level heat exchange unit of the second-level heat exchange unit, and the second-level heat exchange unit is the lower-level heat exchange unit of the first-level heat exchange unit; the gas-liquid separation unit can receive the condensate of the upper-level heat exchange unit, and the steam generated by mixing the condensate of the upper-level heat exchange unit and the primary steam is injected into the lower-level heat exchange unit, thereby realizing the cyclic and graded utilization of steam.

[0063] It should also be noted that the number of gas-liquid separation units can be set according to specific needs. It can be understood that the number of gas-liquid separation units can be multiple, and a gas-liquid separation unit is set between two adjacent heat exchange units; of course, if Figure 1 As shown, the number of the gas-liquid separation unit may also be one.

[0064] It should also be noted that the secondary steam is transported to a multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into a secondary condensate. It can be understood that the secondary condensate can be injected into a steam generating device or into a next-stage heat exchange unit.

[0065] It should also be noted that both the primary condensate and the secondary condensate are vapor-liquid mixtures. The temperature of the primary condensate is 160-180°C, and the temperature of the secondary condensate is 105°C. Therefore, recycling the primary condensate and the secondary condensate can reduce energy waste.

[0066] It should also be noted that if only the primary condensate is injected into the steam separated by the gas-liquid separation unit 30 as secondary steam, then the primary steam after use is simply reused, and the secondary steam has poor quality and low utilization efficiency, which cannot meet the requirements. Therefore, by using the steam obtained by mixing the primary condensate with the primary steam as secondary steam, the quality of the secondary steam is improved, the heat exchange efficiency can be guaranteed, and the steam requirements of the multi-stage heat exchange unit can be met.

[0067] Embodiment 2

[0068] like Figure 1 As shown, the steam multi-stage utilization system includes a steam generating device 10, a multi-stage heat exchange unit and a gas-liquid separation unit 30; the steam generating device 10 is used to generate primary steam; the multi-stage heat exchange unit is connected to the steam generating device 10, and is used to receive primary steam for heat exchange, and convert the primary steam into primary condensate; the gas-liquid separation unit 30 is connected to the multi-stage heat exchange unit and the steam generating device 10, and is used to receive primary condensate and primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange to convert the secondary steam into secondary condensate.

[0069] As can be seen from the above, by setting up a multi-stage heat exchange unit to receive primary steam and secondary steam respectively, the graded utilization of steam is realized, ensuring that steam of different qualities can be used. By using the primary condensate generated by condensation after heat exchange in the multi-stage heat exchange unit as one of the sources of secondary steam, the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit 30, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam temperature reduction is transferred to the primary condensate, and the primary condensate is boiled again when it encounters heat and converted into steam and mixed with the primary steam to form secondary steam for use by the multi-stage heat exchange unit, thereby realizing the effective utilization of the primary condensate, avoiding the waste of heat in the primary condensate, reducing the discharge and loss of heat, reducing the consumption of saturated steam, improving the steam quality and heat exchange efficiency, and greatly reducing the production cost of pulp molding.

[0070] It should be noted that the steam generating device 10 includes but is not limited to a boiler; the primary steam may be saturated steam generated by a boiler or waste heat steam from a power plant.

[0071] It should also be noted that the multi-stage heat exchange unit includes multiple heat exchange units. Since the quality of steam is different when the heat exchange unit reuses the steam, in order to distinguish the multiple heat exchange units, the multiple heat exchange units can be named in sequence according to the first level, second level, third level, fourth level, etc., a first-level heat exchange unit, a second-level heat exchange unit, a third-level heat exchange unit, a fourth-level heat exchange unit, etc.; it can be understood that the first-level heat exchange unit and the second-level heat exchange unit are adjacent heat exchange units, and the first-level heat exchange unit is the upper-level heat exchange unit of the second-level heat exchange unit, and the second-level heat exchange unit is the lower-level heat exchange unit of the first-level heat exchange unit; the gas-liquid separation unit can receive the condensate of the upper-level heat exchange unit, and the steam generated by mixing the condensate of the upper-level heat exchange unit and the primary steam is injected into the lower-level heat exchange unit, thereby realizing the cyclic and graded utilization of steam.

[0072] It should also be noted that the number of gas-liquid separation units can be set according to specific needs. It can be understood that the number of gas-liquid separation units can be multiple, and a gas-liquid separation unit is set between two adjacent heat exchange units; of course, if Figure 1 As shown, the number of the gas-liquid separation unit may also be one.

[0073] It should also be noted that the secondary steam is transported to a multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into a secondary condensate. It can be understood that the secondary condensate can be injected into a steam generating device or into a next-stage heat exchange unit.

[0074] It should also be noted that both the primary condensate and the secondary condensate are vapor-liquid mixtures. The temperature of the primary condensate is 160-180°C, and the temperature of the secondary condensate is 105°C. Therefore, recycling the primary condensate and the secondary condensate can reduce energy waste.

[0075] It should also be noted that if only the primary condensate is injected into the steam separated by the gas-liquid separation unit 30 as secondary steam, then the primary steam after use is simply reused, and the secondary steam has poor quality and low utilization efficiency, which cannot meet the requirements. Therefore, by using the steam obtained by mixing the primary condensate with the primary steam as secondary steam, the quality of the secondary steam is improved, the heat exchange efficiency can be guaranteed, and the steam requirements of the multi-stage heat exchange unit can be met.

[0076] In some embodiments, the multi-stage heat exchange unit includes a primary heat exchange unit and a secondary heat exchange unit; the inlet and outlet of the primary heat exchange unit are respectively connected to the steam generating device and the gas-liquid separation unit, and the primary heat exchange unit is used to receive primary steam for primary heat exchange and convert the primary steam into primary condensate; the inlet and outlet of the secondary heat exchange unit are respectively connected to the gas-liquid separation unit and the steam generating device, and the secondary heat exchange unit is used to receive secondary steam for secondary heat exchange and convert the secondary steam into secondary condensate, and the secondary condensate is injected into the steam generating device.

[0077] The secondary condensate generated by the condensation of the secondary heat exchange unit with the secondary steam is injected into the steam generating device to achieve closed-loop use of steam, ensuring that all the heat of the condensed steam is utilized and can be recovered, thereby establishing a closed-loop internal circulation of steam, achieving multi-stage closed-loop utilization of steam and reducing steam consumption.

[0078] It should be noted that the primary heat exchange unit 20 and the secondary heat exchange unit 40 include but are not limited to pulp molding equipment and thermal oil molds. In addition, the product steam energy consumption is determined as A according to the number of the primary heat exchange unit 20 and the secondary heat exchange unit 40, and the steam generating device 10 is selected according to the product steam energy consumption. The steam volume of the steam generating device 10 needs to be 1.2A-1.5A; and the number of the primary heat exchange unit 20 is twice the number of the secondary heat exchange unit 40, so as to ensure that more steam can be used by the secondary heat exchange unit 40. Because the quality of the secondary steam is lower than that of the primary steam, the drying efficiency of the secondary heat exchange unit 40 is 80%-90% of the drying efficiency of the primary heat exchange unit 20.

[0079] It should also be noted that the multi-stage steam utilization system further includes a water supply tank 60 , which is connected to the steam generating device 10 and the secondary heat exchange unit 40 , respectively.

[0080] In some embodiments, the gas-liquid separation unit 30 includes multiple gas-liquid separation tanks 310, a first delivery pipe 320, a second delivery pipe 330 and a steam trap 50; a first inlet pipe 3101 and a second inlet pipe 3102 are provided on the gas-liquid separation tank 310; one end of the first delivery pipe 320 is connected to the primary heat exchange unit 20 and the other end is connected to the first inlet pipe 3101; one end of the second delivery pipe 330 is connected to the steam generating device 10 and the other end is connected to the second inlet pipe 3102; the steam trap is provided on the first delivery pipe.

[0081] By setting up a gas-liquid separation tank 310 to separate the primary condensate from the secondary steam, the quality of the secondary steam transported to the secondary heat exchange equipment is improved, and multiple gas-liquid separation tanks 310 can be used to sequentially transport secondary steam to the secondary heat exchange unit 40, ensuring the continuity of multi-stage steam utilization and avoiding interruption due to insufficient secondary steam. By setting up a first delivery pipe 320 connected to multiple first inlet pipes 3101 respectively, a structural basis is provided for injecting primary condensate into multiple gas-liquid separation tanks 310, and by setting up a second delivery pipe 330 connected to multiple second inlet pipes 3102 respectively, a structural basis is provided for injecting primary steam into multiple gas-liquid separation tanks 310. The steam trap 50 plays the role of steam blocking and water drainage, and the primary condensate is automatically discharged.

[0082] It should be noted that the multiple gas-liquid separation tanks 310 sequentially deliver secondary steam to the secondary heat exchange unit 40. Therefore, during the operation, there will always be a gas-liquid separation tank 310 delivering secondary steam to the secondary heat exchange unit 40. When the primary condensate is injected into one of the gas-liquid separation tanks 310, other gas-liquid separation tanks 310 will also deliver secondary steam to the secondary heat exchange unit 40 at the same time. Therefore, the working pace of each gas-liquid separation tank 310 is inconsistent. Injecting primary condensate and secondary steam into multiple gas-liquid separation tanks 310 in sequence is more in line with the working rhythm. Moreover, the pressure in other gas-liquid separation tanks 310 is greater than the pressure of the primary condensate. If the primary condensate is injected into multiple gas-liquid separation tanks 310 at the same time, instead of sequentially and individually injecting, the primary condensate of the steam trap 50 cannot be discharged. Therefore, it is necessary to inject primary condensate and primary steam into each gas-liquid separation tank 310 in sequence and separately.

[0083] It should also be noted that the number of gas-liquid separation tanks 310 is set according to specific needs, and this application does not limit it; for example, Figure 1 As shown, the number of gas separation tanks is three.

[0084] It should also be noted that the amount of steam required by the primary heat exchange unit 20 is Q, and the amount of steam provided by the steam generating device 10 to the primary heat exchange unit 20 is 2Q, thereby ensuring that the vapor-liquid mass ratio of the primary condensate passing through the steam trap 50 is 1:1. By setting the vapor-liquid mass ratio of the primary condensate of the steam trap 50 to 1:1, the heat exchange efficiency is ensured, the high and low pressure differences of the steam are effectively utilized, and the flow rate of the steam is ensured.

[0085] Embodiment 3

[0086] like Figure 1As shown, the steam multi-stage utilization system includes a steam generating device 10, a multi-stage heat exchange unit and a gas-liquid separation unit 30; the steam generating device 10 is used to generate primary steam; the multi-stage heat exchange unit is connected to the steam generating device 10, and is used to receive primary steam for heat exchange, and convert the primary steam into primary condensate; the gas-liquid separation unit 30 is connected to the multi-stage heat exchange unit and the steam generating device 10, and is used to receive primary condensate and primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange to convert the secondary steam into secondary condensate.

[0087] As can be seen from the above, by setting up a multi-stage heat exchange unit to receive primary steam and secondary steam respectively, the graded utilization of steam is realized, ensuring that steam of different qualities can be used. By using the primary condensate generated by condensation after heat exchange in the multi-stage heat exchange unit as one of the sources of secondary steam, the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit 30, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam temperature reduction is transferred to the primary condensate, and the primary condensate is boiled again when it encounters heat and converted into steam and mixed with the primary steam to form secondary steam for use by the multi-stage heat exchange unit, thereby realizing the effective utilization of the primary condensate, avoiding the waste of heat in the primary condensate, reducing the discharge and loss of heat, reducing the consumption of saturated steam, improving the steam quality and heat exchange efficiency, and greatly reducing the production cost of pulp molding.

[0088] It should be noted that the steam generating device 10 includes but is not limited to a boiler; the primary steam may be saturated steam generated by a boiler or waste heat steam from a power plant.

[0089] It should also be noted that the multi-stage heat exchange unit includes multiple heat exchange units. Since the quality of steam is different when the heat exchange unit reuses the steam, in order to distinguish the multiple heat exchange units, the multiple heat exchange units can be named in sequence according to the first level, second level, third level, fourth level, etc., a first-level heat exchange unit, a second-level heat exchange unit, a third-level heat exchange unit, a fourth-level heat exchange unit, etc.; it can be understood that the first-level heat exchange unit and the second-level heat exchange unit are adjacent heat exchange units, and the first-level heat exchange unit is the upper-level heat exchange unit of the second-level heat exchange unit, and the second-level heat exchange unit is the lower-level heat exchange unit of the first-level heat exchange unit; the gas-liquid separation unit can receive the condensate of the upper-level heat exchange unit, and the steam generated by mixing the condensate of the upper-level heat exchange unit and the primary steam is injected into the lower-level heat exchange unit, thereby realizing the cyclic and graded utilization of steam.

[0090] It should also be noted that the number of gas-liquid separation units can be set according to specific needs. It can be understood that the number of gas-liquid separation units can be multiple, and a gas-liquid separation unit is set between two adjacent heat exchange units; of course, if Figure 1As shown, the number of the gas-liquid separation unit may also be one.

[0091] It should also be noted that the secondary steam is transported to a multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into a secondary condensate. It can be understood that the secondary condensate can be injected into a steam generating device or into a next-stage heat exchange unit.

[0092] It should also be noted that both the primary condensate and the secondary condensate are vapor-liquid mixtures. The temperature of the primary condensate is 160-180°C, and the temperature of the secondary condensate is 105°C. Therefore, recycling the primary condensate and the secondary condensate can reduce energy waste.

[0093] It should also be noted that if only the primary condensate is injected into the steam separated by the gas-liquid separation unit 30 as secondary steam, then the primary steam after use is simply reused, and the secondary steam has poor quality and low utilization efficiency, which cannot meet the requirements. Therefore, by using the steam obtained by mixing the primary condensate with the primary steam as secondary steam, the quality of the secondary steam is improved, the heat exchange efficiency can be guaranteed, and the steam requirements of the multi-stage heat exchange unit can be met.

[0094] In some embodiments, the multi-stage heat exchange unit includes a primary heat exchange unit and a secondary heat exchange unit; the inlet and outlet of the primary heat exchange unit are respectively connected to the steam generating device and the gas-liquid separation unit, and the primary heat exchange unit is used to receive primary steam for primary heat exchange and convert the primary steam into primary condensate; the inlet and outlet of the secondary heat exchange unit are respectively connected to the gas-liquid separation unit and the steam generating device, and the secondary heat exchange unit is used to receive secondary steam for secondary heat exchange and convert the secondary steam into secondary condensate, and the secondary condensate is injected into the steam generating device.

[0095] The secondary condensate generated by the condensation of the secondary heat exchange unit with the secondary steam is injected into the steam generating device to achieve closed-loop use of steam, ensuring that all the heat of the condensed steam is utilized and can be recovered, thereby establishing a closed-loop internal circulation of steam, achieving multi-stage closed-loop utilization of steam and reducing steam consumption.

[0096] It should be noted that the primary heat exchange unit 20 and the secondary heat exchange unit 40 include but are not limited to pulp molding equipment and thermal oil molds. In addition, the product steam energy consumption is determined as A according to the number of the primary heat exchange unit 20 and the secondary heat exchange unit 40, and the steam generating device 10 is selected according to the product steam energy consumption. The steam volume of the steam generating device 10 needs to be 1.2A-1.5A; and the number of the primary heat exchange unit 20 is twice the number of the secondary heat exchange unit 40, so as to ensure that more steam can be used by the secondary heat exchange unit 40. Because the quality of the secondary steam is lower than that of the primary steam, the drying efficiency of the secondary heat exchange unit 40 is 80%-90% of the drying efficiency of the primary heat exchange unit 20.

[0097] It should also be noted that the multi-stage steam utilization system further includes a water supply tank 60 , which is connected to the steam generating device 10 and the secondary heat exchange unit 40 , respectively.

[0098] In some embodiments, the gas-liquid separation unit 30 includes multiple gas-liquid separation tanks 310, a first delivery pipe 320, a second delivery pipe 330 and a steam trap 50; a first inlet pipe 3101 and a second inlet pipe 3102 are provided on the gas-liquid separation tank 310; one end of the first delivery pipe 320 is connected to the primary heat exchange unit 20 and the other end is connected to the first inlet pipe 3101; one end of the second delivery pipe 330 is connected to the steam generating device 10 and the other end is connected to the second inlet pipe 3102; the steam trap is provided on the first delivery pipe.

[0099] By setting up a gas-liquid separation tank 310 to separate the primary condensate from the secondary steam, the quality of the secondary steam transported to the secondary heat exchange equipment is improved, and multiple gas-liquid separation tanks 310 can be used to sequentially transport secondary steam to the secondary heat exchange unit 40, ensuring the continuity of multi-stage steam utilization and avoiding interruption due to insufficient secondary steam. By setting up a first delivery pipe 320 connected to multiple first inlet pipes 3101 respectively, a structural basis is provided for injecting primary condensate into multiple gas-liquid separation tanks 310, and by setting up a second delivery pipe 330 connected to multiple second inlet pipes 3102 respectively, a structural basis is provided for injecting primary steam into multiple gas-liquid separation tanks 310. The steam trap 50 plays the role of steam blocking and water drainage, and the primary condensate is automatically discharged.

[0100] It should be noted that the multiple gas-liquid separation tanks 310 sequentially deliver secondary steam to the secondary heat exchange unit 40. Therefore, during the operation, there will always be a gas-liquid separation tank 310 delivering secondary steam to the secondary heat exchange unit 40. When the primary condensate is injected into one of the gas-liquid separation tanks 310, other gas-liquid separation tanks 310 will also deliver secondary steam to the secondary heat exchange unit 40 at the same time. Therefore, the working pace of each gas-liquid separation tank 310 is inconsistent. Injecting primary condensate and secondary steam into multiple gas-liquid separation tanks 310 in sequence is more in line with the working rhythm. Moreover, the pressure in other gas-liquid separation tanks 310 is greater than the pressure of the primary condensate. If the primary condensate is injected into multiple gas-liquid separation tanks 310 at the same time, instead of sequentially and individually injecting, the primary condensate of the steam trap 50 cannot be discharged. Therefore, it is necessary to inject primary condensate and primary steam into each gas-liquid separation tank 310 in sequence and separately.

[0101] It should also be noted that the number of gas-liquid separation tanks 310 is set according to specific needs, and this application does not limit it; for example, Figure 1 As shown, the number of gas separation tanks is three.

[0102] It should also be noted that the amount of steam required by the primary heat exchange unit 20 is Q, and the amount of steam provided by the steam generating device 10 to the primary heat exchange unit 20 is 2Q, thereby ensuring that the vapor-liquid mass ratio of the primary condensate passing through the steam trap 50 is 1:1. By setting the vapor-liquid mass ratio of the primary condensate of the steam trap 50 to 1:1, the heat exchange efficiency is ensured, the high and low pressure differences of the steam are effectively utilized, and the flow rate of the steam is ensured.

[0103] In some embodiments, a steam outlet pipe 3103 is provided on the gas-liquid separation tank 310 , wherein the gas-liquid separation unit 30 further includes a third delivery pipe 340 , one end of the third delivery pipe 340 is connected to the steam outlet pipe 3103 and the other end is connected to the secondary heat exchange unit 40 .

[0104] The secondary steam in the gas-liquid separation tank 310 is transported to the secondary heat exchange unit 40 through the steam outlet pipe 3103, providing a structural basis for the secondary heat exchange unit 40 to utilize the secondary steam.

[0105] Embodiment 4

[0106] like Figure 1As shown, the steam multi-stage utilization system includes a steam generating device 10, a multi-stage heat exchange unit and a gas-liquid separation unit 30; the steam generating device 10 is used to generate primary steam; the multi-stage heat exchange unit is connected to the steam generating device 10, and is used to receive primary steam for heat exchange, and convert the primary steam into primary condensate; the gas-liquid separation unit 30 is connected to the multi-stage heat exchange unit and the steam generating device 10, and is used to receive primary condensate and primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange to convert the secondary steam into secondary condensate.

[0107] As can be seen from the above, by setting up a multi-stage heat exchange unit to receive primary steam and secondary steam respectively, the graded utilization of steam is realized, ensuring that steam of different qualities can be used. By using the primary condensate generated by condensation after heat exchange in the multi-stage heat exchange unit as one of the sources of secondary steam, the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit 30, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam temperature reduction is transferred to the primary condensate, and the primary condensate is boiled again when it encounters heat and converted into steam and mixed with the primary steam to form secondary steam for use by the multi-stage heat exchange unit, thereby realizing the effective utilization of the primary condensate, avoiding the waste of heat in the primary condensate, reducing the discharge and loss of heat, reducing the consumption of saturated steam, improving the steam quality and heat exchange efficiency, and greatly reducing the production cost of pulp molding.

[0108] It should be noted that the steam generating device 10 includes but is not limited to a boiler; the primary steam may be saturated steam generated by a boiler or waste heat steam from a power plant.

[0109] It should also be noted that the multi-stage heat exchange unit includes multiple heat exchange units. Since the quality of steam is different when the heat exchange unit reuses the steam, in order to distinguish the multiple heat exchange units, the multiple heat exchange units can be named in sequence according to the first level, second level, third level, fourth level, etc., a first-level heat exchange unit, a second-level heat exchange unit, a third-level heat exchange unit, a fourth-level heat exchange unit, etc.; it can be understood that the first-level heat exchange unit and the second-level heat exchange unit are adjacent heat exchange units, and the first-level heat exchange unit is the upper-level heat exchange unit of the second-level heat exchange unit, and the second-level heat exchange unit is the lower-level heat exchange unit of the first-level heat exchange unit; the gas-liquid separation unit can receive the condensate of the upper-level heat exchange unit, and the steam generated by mixing the condensate of the upper-level heat exchange unit and the primary steam is injected into the lower-level heat exchange unit, thereby realizing the cyclic and graded utilization of steam.

[0110] It should also be noted that the number of gas-liquid separation units can be set according to specific needs. It can be understood that the number of gas-liquid separation units can be multiple, and a gas-liquid separation unit is set between two adjacent heat exchange units; of course, if Figure 1As shown, the number of the gas-liquid separation unit may also be one.

[0111] It should also be noted that the secondary steam is transported to a multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into a secondary condensate. It can be understood that the secondary condensate can be injected into a steam generating device or into a next-stage heat exchange unit.

[0112] It should also be noted that both the primary condensate and the secondary condensate are vapor-liquid mixtures. The temperature of the primary condensate is 160-180°C, and the temperature of the secondary condensate is 105°C. Therefore, recycling the primary condensate and the secondary condensate can reduce energy waste.

[0113] It should also be noted that if only the primary condensate is injected into the steam separated by the gas-liquid separation unit 30 as secondary steam, then the primary steam after use is simply reused, and the secondary steam has poor quality and low utilization efficiency, which cannot meet the requirements. Therefore, by using the steam obtained by mixing the primary condensate with the primary steam as secondary steam, the quality of the secondary steam is improved, the heat exchange efficiency can be guaranteed, and the steam requirements of the multi-stage heat exchange unit can be met.

[0114] In some embodiments, the multi-stage heat exchange unit includes a primary heat exchange unit and a secondary heat exchange unit; the inlet and outlet of the primary heat exchange unit are respectively connected to the steam generating device and the gas-liquid separation unit, and the primary heat exchange unit is used to receive primary steam for primary heat exchange and convert the primary steam into primary condensate; the inlet and outlet of the secondary heat exchange unit are respectively connected to the gas-liquid separation unit and the steam generating device, and the secondary heat exchange unit is used to receive secondary steam for secondary heat exchange and convert the secondary steam into secondary condensate, and the secondary condensate is injected into the steam generating device.

[0115] The secondary condensate generated by the condensation of the secondary heat exchange unit with the secondary steam is injected into the steam generating device to achieve closed-loop use of steam, ensuring that all the heat of the condensed steam is utilized and can be recovered, thereby establishing a closed-loop internal circulation of steam, achieving multi-stage closed-loop utilization of steam and reducing steam consumption.

[0116] It should be noted that the primary heat exchange unit 20 and the secondary heat exchange unit 40 include but are not limited to pulp molding equipment and thermal oil molds. In addition, the product steam energy consumption is determined as A according to the number of the primary heat exchange unit 20 and the secondary heat exchange unit 40, and the steam generating device 10 is selected according to the product steam energy consumption. The steam volume of the steam generating device 10 needs to be 1.2A-1.5A; and the number of the primary heat exchange unit 20 is twice the number of the secondary heat exchange unit 40, so as to ensure that more steam can be used by the secondary heat exchange unit 40. Because the quality of the secondary steam is lower than that of the primary steam, the drying efficiency of the secondary heat exchange unit 40 is 80%-90% of the drying efficiency of the primary heat exchange unit 20.

[0117] It should also be noted that the multi-stage steam utilization system further includes a water supply tank 60 , which is connected to the steam generating device 10 and the secondary heat exchange unit 40 , respectively.

[0118] In some embodiments, the gas-liquid separation unit 30 includes multiple gas-liquid separation tanks 310, a first delivery pipe 320, a second delivery pipe 330 and a steam trap 50; a first inlet pipe 3101 and a second inlet pipe 3102 are provided on the gas-liquid separation tank 310; one end of the first delivery pipe 320 is connected to the primary heat exchange unit 20 and the other end is connected to the first inlet pipe 3101; one end of the second delivery pipe 330 is connected to the steam generating device 10 and the other end is connected to the second inlet pipe 3102; the steam trap is provided on the first delivery pipe.

[0119] By setting up a gas-liquid separation tank 310 to separate the primary condensate from the secondary steam, the quality of the secondary steam transported to the secondary heat exchange equipment is improved, and multiple gas-liquid separation tanks 310 can be used to sequentially transport secondary steam to the secondary heat exchange unit 40, ensuring the continuity of multi-stage steam utilization and avoiding interruption due to insufficient secondary steam. By setting up a first delivery pipe 320 connected to multiple first inlet pipes 3101 respectively, a structural basis is provided for injecting primary condensate into multiple gas-liquid separation tanks 310, and by setting up a second delivery pipe 330 connected to multiple second inlet pipes 3102 respectively, a structural basis is provided for injecting primary steam into multiple gas-liquid separation tanks 310. The steam trap 50 plays the role of steam blocking and water drainage, and the primary condensate is automatically discharged.

[0120] It should be noted that the multiple gas-liquid separation tanks 310 sequentially deliver secondary steam to the secondary heat exchange unit 40. Therefore, during the operation, there will always be a gas-liquid separation tank 310 delivering secondary steam to the secondary heat exchange unit 40. When the primary condensate is injected into one of the gas-liquid separation tanks 310, other gas-liquid separation tanks 310 will also deliver secondary steam to the secondary heat exchange unit 40 at the same time. Therefore, the working pace of each gas-liquid separation tank 310 is inconsistent. Injecting primary condensate and secondary steam into multiple gas-liquid separation tanks 310 in sequence is more in line with the working rhythm. Moreover, the pressure in other gas-liquid separation tanks 310 is greater than the pressure of the primary condensate. If the primary condensate is injected into multiple gas-liquid separation tanks 310 at the same time, instead of sequentially and individually injecting, the primary condensate of the steam trap 50 cannot be discharged. Therefore, it is necessary to inject primary condensate and primary steam into each gas-liquid separation tank 310 in sequence and separately.

[0121] It should also be noted that the number of gas-liquid separation tanks 310 is set according to specific needs, and this application does not limit it; for example, Figure 1 As shown, the number of gas separation tanks is three.

[0122] It should also be noted that the amount of steam required by the primary heat exchange unit 20 is Q, and the amount of steam provided by the steam generating device 10 to the primary heat exchange unit 20 is 2Q, thereby ensuring that the vapor-liquid mass ratio of the primary condensate passing through the steam trap 50 is 1:1. By setting the vapor-liquid mass ratio of the primary condensate of the steam trap 50 to 1:1, the heat exchange efficiency is ensured, the high and low pressure differences of the steam are effectively utilized, and the flow rate of the steam is ensured.

[0123] In some embodiments, a steam outlet pipe 3103 is provided on the gas-liquid separation tank 310 , wherein the gas-liquid separation unit 30 further includes a third delivery pipe 340 , one end of the third delivery pipe 340 is connected to the steam outlet pipe 3103 and the other end is connected to the secondary heat exchange unit 40 .

[0124] The secondary steam in the gas-liquid separation tank 310 is transported to the secondary heat exchange unit 40 through the steam outlet pipe 3103, providing a structural basis for the secondary heat exchange unit 40 to utilize the secondary steam.

[0125] In some embodiments, the gas-liquid separation unit 30 also includes a first valve 350, a second valve 360 ​​and a third valve 370; the first valve 350 is arranged on the first inlet pipe 3101 to control the on-off of the first inlet pipe 3101; the second valve 360 ​​is arranged on the second inlet pipe 3102 to control the on-off of the second inlet pipe 3102; the third valve 370 is arranged on the steam outlet pipe 3103 to control the on-off of the steam outlet pipe 3103.

[0126] By setting the first valve 350, the on-off of the first inlet pipe 3101 can be controlled, thereby controlling the process of injecting the primary condensate into the gas-liquid separation tank 310; by setting the second valve 360, the on-off of the second inlet pipe 3102 can be controlled, thereby controlling the process of injecting the primary steam into the gas-liquid separation tank 310; by setting the third valve 370, the on-off of the steam outlet pipe 3103 can be controlled, thereby controlling the process of transporting the secondary steam to the secondary heat exchange unit 40.

[0127] It should be noted that the third valve 370 includes but is not limited to a one-way valve.

[0128] Embodiment 5

[0129] like Figure 2 As shown, an embodiment of the present invention provides a multi-stage steam utilization method, which is applied to the multi-stage steam utilization system as described in any embodiment, comprising:

[0130] S101: generating primary steam by the steam generating device;

[0131] It should be noted that the primary steam can be saturated steam generated by a boiler or waste heat steam from a power plant.

[0132] S102: transporting the primary steam to the multi-stage heat exchange unit for heat exchange, and converting the primary steam into primary condensate;

[0133] It should be noted that the primary condensate is formed by condensing the primary steam through heat exchange in a multi-stage heat exchange unit; the primary condensate is a vapor-liquid mixture, and the temperature of the primary condensate is 160-180°C.

[0134] S103: injecting the primary condensate and the primary steam into the gas-liquid separation unit in sequence to obtain secondary steam;

[0135] It should be noted that if only the primary condensate is injected into the steam separated by the gas-liquid separation unit 30 as secondary steam, the primary steam after use is simply reused, and the quality of the secondary steam is poor, the utilization efficiency is low, and the requirements cannot be met. Therefore, by using the steam obtained by mixing the primary condensate with the primary steam as secondary steam, the quality of the secondary steam is improved, the utilization efficiency can be guaranteed, and the requirements of the multi-stage heat exchange unit for steam are met.

[0136] It should also be noted that the primary condensate and the primary steam are mixed and heat exchanged in the gas-liquid separation unit 30, and the low-temperature primary condensate meets the high-temperature primary steam to form a new dynamic equilibrium, that is, the heat of the high-temperature primary steam that reduces the temperature is transferred to the primary condensate, and the primary condensate boils again when heated and converts into steam, and then mixes with the primary steam to form secondary steam for use in the multi-stage heat exchange unit.

[0137] In some embodiments, the step of sequentially injecting the primary condensate and the primary steam into the gas-liquid separation unit 30 to obtain secondary steam includes:

[0138] Injecting the primary condensate into the gas-liquid separation unit 30 until the real-time pressure in the gas-liquid separation unit 30 reaches a first preset pressure;

[0139] The primary steam is injected into the gas-liquid separation unit 30 until the real-time pressure in the gas-liquid separation unit 30 reaches a second preset pressure, thereby obtaining the secondary steam.

[0140] It should be noted that the specific value of the first preset pressure P1 is set according to actual needs, and the pressure of the steam outlet pipe 3103 of the steam generating device 10 is P0, wherein P0>P1; controlling the capacity of the primary condensate injected into the gas-liquid separation unit 30 by the first preset pressure can not only ensure the quality of the secondary steam, but also reduce energy consumption, thereby avoiding excessive injection of primary condensate to affect the quality of the secondary steam, and avoiding insufficient injection of primary condensate to increase energy consumption.

[0141] It should also be noted that the specific value of the second preset pressure P2 is set according to actual needs, wherein P0>P2>P1; controlling the capacity of the primary steam injected into the gas-liquid separation unit 30 by the second preset pressure can not only ensure the quality of the secondary steam, but also reduce energy consumption, thereby avoiding excessive primary steam injection and increased energy consumption, and avoiding insufficient primary steam injection and affecting the quality of the secondary steam.

[0142] In some embodiments, the gas-liquid separation unit 30 includes a plurality of gas-liquid separation tanks 310;

[0143] The step of injecting the primary condensate into the gas-liquid separation unit 30 until the real-time pressure in the gas-liquid separation unit 30 reaches a first preset pressure comprises: injecting the primary condensate into the plurality of gas-liquid separation tanks 310 in sequence until the real-time pressure in the plurality of gas-liquid separation tanks 310 reaches the first preset pressure in sequence;

[0144] The injecting the primary steam into the gas-liquid separation unit 30 until the real-time pressure inside the gas-liquid separation unit 30 reaches the second preset pressure to obtain the secondary steam comprises: injecting the primary steam into the plurality of gas-liquid separation tanks 310 in sequence until the real-time pressure inside the plurality of gas-liquid separation tanks 310 reaches the second preset pressure in sequence to obtain the secondary steam in sequence.

[0145] It should be noted that by sequentially injecting primary condensate and secondary steam into the plurality of gas-liquid separation tanks 310 , primary condensate and secondary steam are separately injected, thereby preventing the primary condensate from being unable to be discharged from the steam trap 50 .

[0146] It should also be noted that the number of gas-liquid separation tanks 310 is set according to actual needs, and this application does not impose specific restrictions; multiple gas-liquid separation tanks 310 can be connected in parallel, and each gas-liquid separation tank 310 is provided with a first inlet pipe 3101 as an injection port for primary condensate. By setting a first valve 350 on the first inlet pipe 3101, the injection of primary condensate is controlled, thereby realizing the injection of primary condensate into multiple gas-liquid separation tanks 310 in sequence; in addition, each gas-liquid separation tank 310 is provided with a second inlet pipe 3102 as an injection port for primary steam. By setting a second valve 360 ​​on the second inlet pipe 3102, the injection of primary steam is controlled, thereby realizing the injection of primary steam into multiple gas-liquid separation tanks 310 in sequence.

[0147] For example, Figure 1 As shown, the number of gas-liquid separation tanks 310 is three, and the three gas-liquid separation tanks 310 are gas-liquid separation tank A, gas-liquid separation tank B and gas-liquid separation tank C, specifically:

[0148] Inject the primary condensate into gas-liquid separation tank A until the pressure in gas-liquid separation tank A reaches a first preset pressure; then stop injecting the primary condensate into gas-liquid separation tank A, and inject the primary condensate into gas-liquid separation tank B until the pressure in gas-liquid separation tank B reaches the first preset pressure; then stop injecting the primary condensate into gas-liquid separation tank B, and inject the primary condensate into gas-liquid separation tank C until the pressure in gas-liquid separation tank C reaches the first preset pressure;

[0149] Inject primary steam into gas-liquid separation tank A until the pressure inside gas-liquid separation tank A reaches the second preset pressure; then stop injecting primary steam into gas-liquid separation tank A, and inject primary steam into gas-liquid separation tank B until the pressure inside gas-liquid separation tank B reaches the second preset pressure; then stop injecting primary steam into gas-liquid separation tank B, and inject primary steam into gas-liquid separation tank C until the pressure inside gas-liquid separation tank C reaches the second preset pressure; any one of gas-liquid separation tank A, gas-liquid separation tank B, and gas-liquid separation tank C can be selected to deliver secondary steam to the secondary heat exchange unit 40.

[0150] In some embodiments, injecting the primary steam into the gas-liquid separation unit 30 until the pressure in the gas-liquid separation unit 30 reaches a second preset pressure to obtain the secondary steam further includes:

[0151] Obtaining the liquid level of the primary condensate in the gas-liquid separation unit 30;

[0152] If the liquid level is lower than the preset liquid level threshold, the injection of the primary steam into the gas-liquid separation unit 30 is stopped.

[0153] It should be noted that the injection of primary steam into the gas-liquid separation unit 30 is controlled by the liquid level of the primary condensate to ensure that the output secondary steam is saturated steam, and the heat exchange of the secondary heat exchange unit 40 utilizes the latent heat of steam; when the liquid level of the primary condensate is less than the preset threshold, that is, the primary condensate injected into the gas-liquid separation unit 30 has been basically used up, at this time, the gas-liquid separation unit 30 injects and outputs primary steam. Therefore, it is necessary to stop injecting primary steam into the gas-liquid separation unit 30 to reduce the consumption of primary steam.

[0154] It should also be noted that the gas-liquid separation unit 30 includes a plurality of gas-liquid separation tanks 310. For each gas-liquid separation tank 310, the injection of primary steam is controlled by the liquid level height. That is, when the liquid level height of the primary condensate in the gas-liquid separation tank 310 that currently transports the secondary steam is less than the preset liquid level threshold, the steam generating device 10 stops injecting primary steam into the gas-liquid separation tank 310. Of course, the steam generating device 10 can continue to inject primary steam into another gas-liquid separation tank 310 at this time until its pressure reaches the second preset pressure. For example, when the pressure in the gas-liquid separation tank A reaches the second preset pressure, the secondary steam in the gas-liquid separation tank A is transported to the secondary heat exchange unit 40 to obtain the liquid level height of the primary condensate in the gas-liquid separation tank A. If the liquid level height is less than the preset liquid level threshold, the steam generating device 10 stops injecting primary steam into the gas-liquid separation tank A, and the steam generating device 10 can inject primary steam into the gas-liquid separation tank B at this time until the pressure reaches the second preset pressure.

[0155] It should also be noted that the liquid level height of the primary condensate in the gas-liquid separation tank 310 can be obtained by setting a liquid level sensor in the gas-liquid separation tank 310; the specific value of the preset liquid level threshold can be set according to actual needs, for example, the preset liquid level threshold can be 100-300 mm from the bottom of the gas-liquid separation tank 310.

[0156] S104: transporting the secondary steam to the multi-stage heat exchange unit for heat exchange, and converting the secondary steam into secondary condensate.

[0157] In some embodiments, the multi-stage heat exchange unit includes a primary heat exchange unit 20 and a secondary heat exchange unit 40;

[0158] The delivering the primary steam to the multi-stage heat exchange unit for heat exchange and converting the primary steam into primary condensate is specifically: delivering the primary steam to the first-stage heat exchange unit 20 for one heat exchange and converting the primary steam into primary condensate;

[0159] The delivering the secondary steam to the multi-stage heat exchange unit for heat exchange and converting the secondary steam into secondary condensate is specifically: delivering the secondary steam to the secondary heat exchange unit 40 for secondary heat exchange and converting the secondary steam into secondary condensate.

[0160] It should be noted that the amount of steam required by the primary heat exchange unit 20 is Q, and the amount of steam provided by the steam generating device 10 to the primary heat exchange unit 20 is 2Q, so that the vapor-liquid mass ratio in the primary condensate is 1:1, thereby ensuring the heat exchange efficiency.

[0161] It should also be noted that the gas-liquid separation unit 30 includes multiple gas-liquid separation tanks 310, and one gas-liquid separation tank 310 is selected each time to transport secondary steam to the secondary heat exchange unit 40. Multiple gas-liquid separation tanks 310 can be connected in parallel, and each gas-liquid separation tank 310 is provided with a steam outlet pipe 3103 as the output port of the secondary steam. By setting a third valve 370 on the steam outlet pipe 3103, the transportation of the secondary steam is controlled, thereby realizing the secondary steam being transported from multiple gas-liquid separation tanks 310 to the secondary heat exchange unit 40 in sequence.

[0162] It should also be noted that the secondary condensate is formed by condensation of the secondary steam after secondary heat exchange in the secondary heat exchange unit 40; the secondary condensate is a vapor-liquid mixture, and the temperature of the secondary condensate is 105°C.

[0163] It should also be noted that the multi-stage heat exchange unit includes multiple heat exchange units. Since the quality of steam is different when the heat exchange unit reuses the steam, in order to distinguish the heat exchange units, the heat exchange units can be named in sequence according to the first level, second level, third level, fourth level, etc., first level heat exchange unit, second level heat exchange unit, third level heat exchange unit, fourth level heat exchange unit, etc.; it can be understood that the first level heat exchange unit and the second level heat exchange unit are adjacent heat exchange units, and the first level heat exchange unit is the upper level heat exchange unit of the second level heat exchange unit, and the second level heat exchange unit is the lower level heat exchange unit of the first level heat exchange unit; the gas-liquid separation unit can receive the condensate of the upper level heat exchange unit, and the steam generated by mixing the condensate of the upper level heat exchange unit and the primary steam is injected into the lower level heat exchange unit to realize the cyclic and graded utilization of steam.

[0164] In some embodiments, the step of transporting the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate further includes:

[0165] The secondary condensate is injected into the steam generating device 10 .

[0166] It should be noted that by injecting the secondary condensate into the steam generating device 10, a closed-loop use of steam is achieved, ensuring that the heat of the condensed steam can be fully utilized and recovered, further reducing energy consumption.

[0167] In some embodiments, the step of transporting the secondary steam to the secondary heat exchange unit 40 for secondary heat exchange and converting the secondary steam into secondary condensate further includes:

[0168] Obtaining the real-time pressure in the gas-liquid separation unit 30;

[0169] If the real-time pressure is less than the third preset pressure, the secondary steam is stopped from being delivered to the secondary heat exchange unit 40 .

[0170] It should be noted that the real-time pressure in the gas-liquid separation tank 310 can be obtained by setting a pressure sensor in the gas-liquid separation tank 310; the specific value of the third preset pressure P3 can be set according to actual needs, where P0>P2>P1>P3, thereby ensuring that the secondary steam can be fully utilized.

[0171] It should also be noted that the gas-liquid separation unit 30 includes a plurality of gas-liquid separation tanks 310. For each gas-liquid separation tank 310, the delivery of secondary steam is controlled by real-time pressure, that is, when the real-time pressure in the gas-liquid separation tank 310 currently delivering secondary steam is less than the third preset pressure, the gas-liquid separation tank 310 stops delivering secondary steam to the secondary heat exchange unit 40, and another gas-liquid separation tank 310 is switched to continue delivering secondary steam to the secondary heat exchange unit 40, and the steam generating device 10 injects primary steam into another gas-liquid separation tank 310; for example, when When the real-time pressure in gas-liquid separation tank A is less than the third preset pressure, gas-liquid separation tank A stops delivering secondary steam to the secondary heat exchange unit 40 and switches to gas-liquid separation tank B to continue delivering secondary steam to the secondary heat exchange unit 40, and at the same time, the steam generating device 10 injects primary steam into gas-liquid separation tank B until the liquid level in gas-liquid separation tank B is less than the preset height threshold, and then stops injecting primary steam into gas-liquid separation tank B. When the real-time pressure in gas-liquid separation tank B is less than the third preset pressure, gas-liquid separation tank B stops delivering secondary steam to the secondary heat exchange unit 40.

[0172] Embodiment 6

[0173] An embodiment of the present invention further provides a molding device, including the multi-stage steam utilization system of any embodiment of the present invention, thereby having all the technical effects brought by the technical solutions of the above embodiments.

[0174] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A multi-stage steam utilization system, characterized in that: include: A steam generating device for generating primary steam; a multi-stage heat exchange unit, connected to the steam generating device, for receiving the primary steam for heat exchange and converting the primary steam into primary condensate; as well as The gas-liquid separation unit is connected to the multi-stage heat exchange unit and the steam generating device, and is used to receive the primary condensate and the primary steam to obtain secondary steam, and transport the secondary steam to the multi-stage heat exchange unit for heat exchange so that the secondary steam is converted into secondary condensate.

2. The multi-stage steam utilization system according to claim 1, characterized in that: The multi-stage heat exchange unit comprises: a primary heat exchange unit, wherein the inlet and the outlet of the primary heat exchange unit are respectively connected to the steam generating device and the gas-liquid separation unit, and the primary heat exchange unit is used to receive the primary steam for a heat exchange and convert the primary steam into a primary condensate; and A secondary heat exchange unit, wherein the inlet and the outlet of the secondary heat exchange unit are respectively connected to the gas-liquid separation unit and the steam generating device, and the secondary heat exchange unit is used to receive the secondary steam for secondary heat exchange and convert the secondary steam into secondary condensate, and the secondary condensate is injected into the steam generating device.

3. The multi-stage steam utilization system according to claim 2, characterized in that: The gas-liquid separation unit comprises: A plurality of gas-liquid separation tanks, each of which is provided with a first inlet pipe and a second inlet pipe; A first delivery pipe, one end of which is connected to the primary heat exchange unit and the other end of which is connected to the first inlet pipe; a second delivery pipe, one end of which is connected to the steam generating device and the other end of which is connected to the second inlet pipe; and The steam trap is arranged on the first delivery pipe.

4. The multi-stage steam utilization system according to claim 3, characterized in that: The gas-liquid separation tank is provided with a steam outlet pipe, wherein the gas-liquid separation unit further comprises a third delivery pipe, one end of the third delivery pipe is connected to the steam outlet pipe and the other end is connected to the secondary heat exchange unit.

5. The multi-stage steam utilization system according to claim 4, characterized in that: The gas-liquid separation unit also includes: A first valve is disposed on the first inlet pipe to control the opening and closing of the first inlet pipe; a second valve, disposed on the second inlet pipe, to control the opening and closing of the second inlet pipe; and The third valve is arranged on the steam outlet pipe to control the opening and closing of the steam outlet pipe.

6. A multi-stage steam utilization method, characterized in that: A multi-stage steam utilization system as claimed in any one of claims 1 to 5, comprising: generating primary steam by the steam generating device; transporting the primary steam to the multi-stage heat exchange unit for heat exchange, and converting the primary steam into primary condensate; injecting the primary condensate and the primary steam into the gas-liquid separation unit in sequence to obtain secondary steam; The secondary steam is transported to the multi-stage heat exchange unit for heat exchange, and the secondary steam is converted into secondary condensate.

7. The multi-stage steam utilization method according to claim 6, characterized in that: The multi-stage heat exchange unit includes a primary heat exchange unit and a secondary heat exchange unit; The delivering the primary steam to the multi-stage heat exchange unit for heat exchange and converting the primary steam into primary condensate is specifically: delivering the primary steam to a first-stage heat exchange unit for one heat exchange and converting the primary steam into primary condensate; The delivering the secondary steam to the multi-stage heat exchange unit for heat exchange and converting the secondary steam into secondary condensate is specifically: delivering the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate.

8. The multi-stage steam utilization method according to claim 6, characterized in that: The step of sequentially injecting the primary condensate and the primary steam into the gas-liquid separation unit to obtain secondary steam comprises: Injecting the primary condensate into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a first preset pressure; The primary steam is injected into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a second preset pressure, thereby obtaining the secondary steam.

9. The multi-stage steam utilization method according to claim 8, characterized in that: The gas-liquid separation unit includes a plurality of gas-liquid separation tanks; The step of injecting the primary condensate into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a first preset pressure comprises: injecting the primary condensate into a plurality of gas-liquid separation tanks in sequence until the real-time pressure in the plurality of gas-liquid separation tanks reaches the first preset pressure in sequence; The step of injecting the primary steam into the gas-liquid separation unit until the real-time pressure inside the gas-liquid separation unit reaches a second preset pressure to obtain the secondary steam comprises: injecting the primary steam into a plurality of gas-liquid separation tanks in sequence until the real-time pressure inside the plurality of gas-liquid separation tanks reaches a second preset pressure in sequence to obtain the secondary steam in sequence.

10. The multi-stage steam utilization method according to claim 8, characterized in that: The step of injecting the primary steam into the gas-liquid separation unit until the real-time pressure in the gas-liquid separation unit reaches a second preset pressure to obtain the secondary steam further comprises: Obtaining the liquid level of the primary condensate in the gas-liquid separation unit; If the liquid level height is less than a preset liquid level threshold, the injection of the primary steam into the gas-liquid separation unit is stopped.

11. The multi-stage steam utilization method according to claim 7, characterized in that: The step of transporting the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate further comprises: The secondary condensate is injected into the steam generating device.

12. The multi-stage steam utilization method according to claim 7, characterized in that: The step of transporting the secondary steam to a secondary heat exchange unit for secondary heat exchange and converting the secondary steam into secondary condensate further comprises: Obtaining the real-time pressure in the gas-liquid separation unit; If the real-time pressure is less than the third preset pressure, the delivery of the secondary steam to the secondary heat exchange unit is stopped.

13. A molding device, characterized in that: It comprises the multi-stage steam utilization system as described in any one of claims 1-5.

Images