Steam oven condensate water waste heat recovery system

Abstract

The utility model discloses a kind of steam oven condensate water waste heat recovery system, it is related to steam oven energy recovery technical field, including steam oven, drain valve, flash tank, check valve, air supply heat exchanger, high-temperature water pump, high-temperature soft water tank, three-way regulating valve, fresh air preheater, air filter and low-temperature soft water tank;Steam condensate water outlet of steam oven is communicated with the water inlet of flash tank by drain valve, secondary steam outlet is equipped on flash tank, secondary steam outlet is communicated with the hot side inlet of air supply heat exchanger by check valve, and the hot side outlet of air supply heat exchanger is communicated with low-temperature soft water tank.The utility model is heated by secondary steam latent heat air supply, and the hierarchical recovery mode of high-temperature condensate water sensible heat preheats fresh air, realizes whole dimension utilization of waste heat, compared with prior art, and steam unit consumption of the system is greatly reduced, and heat utilization is effectively improved.

Description

Technical Field

[0001] This utility model relates to the field of energy recovery technology for steam ovens, specifically to a waste heat recovery system for condensate from a steam oven. Background Technology

[0002] Steam ovens are widely used in industrial production, but their operation suffers from significant energy waste: large amounts of high-temperature condensate are directly discharged through steam traps, not only wasting softened water resources but also easily causing thermal pollution to the environment. To improve this situation, the industry has gradually developed condensate recovery technology, mainly divided into two categories: open-loop recovery and closed-loop recovery.

[0003] A search revealed examples of open-loop heat recovery technologies, such as the patent "A Waste Heat Recovery Mechanism Applicable to Steam Drying Furnaces" (authorization announcement number CN222783893U). This patented technology uses a sliding recovery box to physically collect furnace condensate, reducing equipment corrosion. However, this patent only collects condensate and does not utilize waste heat; therefore, flash steam is released into the atmosphere, resulting in a heat utilization rate of less than 30%, and energy waste remains a significant problem.

[0004] Examples of closed-loop recovery technology include the patent "A Heat Exchange Device and System for Waste Heat Recovery of Condensate from a Stenter" (authorization announcement number CN222336143U). This patented technology uses a single heat exchanger to recover the sensible heat of the condensate and sends hot air back to the drying oven, avoiding water pollution. However, it does not utilize the latent heat of secondary steam, resulting in limited improvement in heat utilization efficiency and failing to fully exploit the energy value of the condensate. Furthermore, it does not establish a graded recovery and recycling system for the condensate, leading to indirect waste of some condensate.

[0005] Furthermore, the patent "Condensate Waste Heat One-Effect Flash Evaporation Natural Air Dehumidification Preheating Drying Oven Device" with authorization announcement number CN202485343U, although the patented technical solution considers the utilization of flash steam and realizes condensate recovery through closed pipeline, introduces a complex device, the lithium bromide refrigerator, which not only significantly increases the structural complexity of the system, but also increases the equipment procurement cost and subsequent maintenance cost. At the same time, the flash steam needs to undergo energy conversion through the lithium bromide refrigerator before indirectly acting on the air treatment, resulting in a long waste heat utilization path and large energy loss in the process.

[0006] In summary, current open-loop recycling systems collect condensate through recycling bins, but flash steam is directly released into the air, resulting in a heat utilization rate of less than 30% and energy waste. While closed-loop recycling systems can recover condensate, they suffer from insufficient utilization of latent heat of secondary steam, and their complex structure, high initial investment costs, and long modification cycles make them difficult to popularize in small and medium-sized enterprises. Utility Model Content

[0007] The purpose of this invention is to provide a steam oven condensate waste heat recovery system with a compact structure, high recovery efficiency, and short modification cycle, so as to solve the problems mentioned in the background art.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows:

[0009] A waste heat recovery system for condensate from a steam oven includes a steam oven, a steam trap, a flash tank, a check valve, a makeup air heat exchanger, a high-temperature water pump, a high-temperature soft water tank, a three-way regulating valve, a fresh air preheater, an air filter, and a low-temperature soft water tank.

[0010] The steam condensate outlet of the steam oven is connected to the inlet of the flash tank via a steam trap. The flash tank is equipped with a secondary steam outlet, which is connected to the hot-side inlet of the make-up air heat exchanger via a check valve. The hot-side outlet of the make-up air heat exchanger is connected to the low-temperature soft water tank. The flash tank is also equipped with a two-way high-temperature condensate outlet, one of which is connected to the high-temperature soft water tank via a high-temperature water pump, and the other is connected to the hot-side inlet of the fresh air preheater via a three-way regulating valve. The hot-side outlet of the fresh air preheater is connected to the low-temperature soft water tank. The cold-side inlet of the fresh air preheater is connected to the outlet of the air filter, and the cold-side outlet of the fresh air preheater is connected to the air inlet of the steam oven.

[0011] Preferably, the make-up air heat exchanger is a finned tube heat exchanger, and the make-up air heat exchanger is installed at the exhaust port of the steam oven.

[0012] Preferably, the fresh air preheater is a plate heat exchanger.

[0013] Preferably, the plates of the plate heat exchanger are made of 304L stainless steel.

[0014] Preferably, the fresh air preheater is designed to withstand a pressure of ≥0.6MPa.

[0015] Preferably, the high-temperature water pump is a centrifugal pump with a temperature resistance of ≥120℃.

[0016] Preferably, the high-temperature water pump is equipped with a variable frequency speed control device, which is used to automatically adjust the flow rate of the high-temperature water pump according to the water level of the high-temperature soft water tank.

[0017] Preferably, the flash tank is a vertical pressure vessel.

[0018] Preferably, the flash tank is equipped with a steam-water separation baffle.

[0019] Preferably, the flash tank is further equipped with a safety valve and a pressure gauge, which are located at the secondary steam outlet.

[0020] Due to the adoption of the above technical solution, the technological progress achieved by this utility model compared to the prior art is as follows:

[0021] This invention achieves full-dimensional utilization of waste heat through a graded recovery mode of "secondary steam latent heat heating of make-up air + high-temperature condensate sensible heat preheating of fresh air". Compared with the existing technology, the steam consumption of this system is greatly reduced. Based on the data of this embodiment, the annual standard coal saving can reach 92t, and the heat utilization rate is effectively improved.

[0022] This utility model system makes full use of the enterprise's existing soft water tank and pipeline network. Only a flash tank, make-up air heat exchanger, fresh air preheater and high temperature water pump need to be added. There is no need to introduce complex equipment. The initial investment cost is low and the transformation cycle is ≤3 days, which can be quickly implemented.

[0023] All equipment in this invention operates at a pressure below 0.3 MPa. Combined with the safety valve on the top of the flash tank and the check valve on the secondary steam pipeline, it forms a double safety protection, eliminating the risk of overpressure. At the same time, the secondary steam is condensed by the make-up air heat exchanger and then connected to the low-temperature soft water tank. The high-temperature condensate is also connected to the soft water tank through two recycling lines, achieving 100% recovery of softened water and avoiding water waste. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the system of this utility model.

[0025] In the diagram: 1. Steam oven; 2. Steam trap; 3. Flash evaporator; 4. Check valve; 5. Make-up air heat exchanger; 6. High-temperature water pump; 7. High-temperature soft water tank; 8. Three-way regulating valve; 9. Fresh air preheater; 10. Air filter; 11. Low-temperature soft water tank. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to embodiments:

[0027] like Figure 1 As shown, this utility model provides a waste heat recovery system for condensate from a steam oven, including a steam oven 1, a steam trap 2, a flash tank 3, a check valve 4, a makeup air heat exchanger 5, a high-temperature water pump 6, a high-temperature soft water tank 7, a three-way regulating valve 8, a fresh air preheater 9, an air filter 10, and a low-temperature soft water tank 11. Specifically, the series and parallel combination structure of the steam oven 1, steam trap 2, flash tank 3, makeup air heat exchanger 5, fresh air preheater 9, and soft water tank enables an integrated process of "secondary steam latent heat utilization → high-temperature condensate sensible heat utilization → condensate recovery," thereby improving heat utilization efficiency.

[0028] The steam condensate outlet of the steam oven 1 is connected to the water inlet of the flash tank 3 through the steam trap 2. Its design function is to realize the directional transportation of high temperature condensate, thereby avoiding the waste of softened water and environmental thermal pollution caused by the direct discharge of high temperature condensate.

[0029] The flash tank 3 is equipped with a secondary steam outlet, which is located at the top of the flash tank 3. The secondary steam outlet is connected to the hot side inlet of the make-up air heat exchanger 5 through the check valve 4. The hot side outlet of the make-up air heat exchanger 5 is connected to the low temperature soft water tank 11. Its design function is to recover the latent heat of the secondary steam and collect the condensate in the subsequent process, so as to solve the problems of flash steam venting and low heat utilization rate in open recovery.

[0030] The flash tank 3 is equipped with two high-temperature condensate outlets. One of the high-temperature condensate outlets is located at the bottom of the flash tank 3. One outlet is connected to the high-temperature soft water tank 7 via the high-temperature water pump 6, and the other outlet is connected to the hot side inlet of the fresh air preheater 9 via the three-way regulating valve 8. The hot side outlet of the fresh air preheater 9 is connected to the low-temperature soft water tank 11. Its design purpose is to recover the sensible heat of the condensate, so as to realize the secondary utilization of the sensible heat of the condensate and solve the problem of insufficient utilization of waste heat in closed-loop recovery.

[0031] The cold side inlet of the fresh air preheater 9 is connected to the outlet of the air filter 10, that is, the cold side inlet of the fresh air preheater 9 is connected to the indoor and outdoor air passing through the air filter 10, and the cold side outlet of the fresh air preheater 9 is connected to the air inlet of the steam oven 1, so that the preheated fresh air directly participates in the oven heating cycle.

[0032] Furthermore, the make-up air heat exchanger 5 is a finned tube heat exchanger, and the make-up air heat exchanger 5 is installed at the exhaust port on the steam oven 1. Through the structural design of the make-up air heat exchanger 5 being close to the circulating air path of the oven, the secondary steam can be directly used to heat the circulating make-up air in the oven, thereby improving the latent heat exchange efficiency of the secondary steam and further solving the problem of heat waste from flash steam.

[0033] Furthermore, the fresh air preheater 9 is a plate heat exchanger, and the plate material of the plate heat exchanger is 304L stainless steel. The design pressure of the fresh air preheater 9 is ≥0.6MPa. The fresh air preheater 9 has a temperature-resistant, corrosion-resistant and pressure-resistant structure, which is suitable for high-temperature condensate working conditions, avoids the interruption of waste heat recovery due to insufficient equipment tolerance, ensures stable sensible heat recovery, and solves the problem of insufficient reliability of closed system operation.

[0034] Furthermore, the high-temperature water pump 6 is a centrifugal pump with a temperature resistance of ≥120℃. The high-temperature water pump 6 is equipped with a variable frequency speed control device, which automatically adjusts the flow rate of the high-temperature water pump 6 according to the water level in the high-temperature soft water tank 7. The variable frequency speed control device uses existing conventional technology, and this paper does not compare or modify it. Therefore, this technology is already well-known and used by those skilled in the art, and will not be elaborated upon further. The main function of the variable frequency speed control device is to control the start-up, shutdown, and flow rate of the high-temperature water pump 6, thereby eliminating the need for manual intervention, avoiding water waste, and solving the problems of low efficiency and high leakage risk associated with manual operation in open-type water recycling systems.

[0035] It should be emphasized that this utility model aims to protect the physical structure, not the circuitry and control program. The description of the processing circuitry and control program in this document is merely to supplement the feasibility and authenticity of this utility model, and this utility model does not seek protection for the program and circuitry technology. Furthermore, it should be emphasized that although the electronic control program is not described in detail in this solution, those skilled in the art can understand and apply it based on their professional knowledge.

[0036] Furthermore, the flash tank 3 is a vertical pressure vessel. The flash tank 3 is equipped with a steam-water separation baffle inside. The top of the flash tank 3 is also equipped with a safety valve and a pressure gauge. The safety valve and pressure gauge are located at the secondary steam outlet. Through the efficient steam-water separation structure and safety protection structure, the secondary steam is fully separated and the system operates safely, solving the problems of incomplete utilization of secondary steam and safety hazards in closed systems.

[0037] The working principle of this steam oven condensate waste heat recovery system will be explained in detail below.

[0038] like Figure 1 As shown, when using this utility model, taking an eight-box hot air drying oven in a textile factory as an example, its operating parameters are: oven steam consumption 600 kg / h, condensate water temperature 105℃, and pressure 0.2 MPa; when adapting to this utility model system, a volume of 0.3 m³ is selected. 3 The flash tank 3 generates approximately 52 kg / h of secondary steam, which can be transferred to a 1200 m³ / h steam tank via the make-up air heat exchanger 5. 3 The circulating air temperature rises by 20℃ per hour; the remaining 548 kg / h of high-temperature condensate is preheated by the fresh air preheater 9, which will reduce the temperature of 2000 m³ / h of the air. 3 The fresh air is preheated from 20℃ to 72℃ per hour. Therefore, calculations show that with 7200 hours of operation per year, this system can save approximately 92 tons of standard coal and recover 3945 tons of softened water, demonstrating significant economic and environmental benefits.

[0039] In summary, this utility model has the following advantages:

[0040] Tiered recovery: This utility model achieves full-dimensional utilization of waste heat through a tiered recovery mode of "secondary steam latent heat heating of make-up air + high-temperature condensate sensible heat preheating of fresh air". Compared with the existing technology (heat utilization rate ≤30%), the steam consumption of this system is greatly reduced. Based on the data of this embodiment, the annual standard coal saving can reach 92t, and the heat utilization rate is effectively improved.

[0041] Low investment: This utility model system makes full use of the enterprise's existing soft water tanks (high temperature soft water tank 7, low temperature soft water tank 11) and pipeline network. Only a flash tank 3, a makeup air heat exchanger 5, a fresh air preheater 9 and a high temperature water pump 6 need to be added. There is no need to introduce complex equipment, the initial investment cost is low, the transformation cycle is ≤3 days, and it can be quickly implemented and applied.

[0042] Reliable operation: All equipment in this invention operates at a pressure below 0.3 MPa. Combined with the safety valve on top of the flash tank 3 and the check valve 4 of the secondary steam pipeline, a double safety protection is formed, eliminating the risk of overpressure. At the same time, the secondary steam is condensed by the make-up air heat exchanger 5 and then connected to the low-temperature soft water tank 11. The high-temperature condensate is also connected to the soft water tank through two recycling lines, achieving 100% recovery of softened water and avoiding water waste.

[0043] It should be noted that this utility model aims to protect the physical structure, and does not protect the circuit, control program, and flow parameters (which can be known by those skilled in the art based on their professional technical knowledge). The mention of the processing circuit, control program, and flow parameters in this article is merely to supplement the explanation of the feasibility and authenticity of this utility model. This utility model does not require protection for the program, circuit, and adjustment or acquisition techniques.

[0044] It should be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joint" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0045] The present invention has been described in detail above. However, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, any modifications or improvements that do not depart from the spirit of the present invention are within the protection scope of the present invention.

Claims

1. A waste heat recovery system for condensate from a steam oven, characterized in that: Includes steam oven, steam trap, flash tank, check valve, make-up air heat exchanger, high temperature water pump, high temperature soft water tank, three-way regulating valve, fresh air preheater, air filter and low temperature soft water tank; The steam condensate outlet of the steam oven is connected to the inlet of the flash tank via a steam trap. The flash tank is equipped with a secondary steam outlet, which is connected to the hot-side inlet of the make-up air heat exchanger via a check valve. The hot-side outlet of the make-up air heat exchanger is connected to the low-temperature soft water tank. The flash tank is also equipped with a two-way high-temperature condensate outlet, one of which is connected to the high-temperature soft water tank via a high-temperature water pump, and the other is connected to the hot-side inlet of the fresh air preheater via a three-way regulating valve. The hot-side outlet of the fresh air preheater is connected to the low-temperature soft water tank. The cold-side inlet of the fresh air preheater is connected to the outlet of the air filter, and the cold-side outlet of the fresh air preheater is connected to the air inlet of the steam oven.

2. The waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The make-up air heat exchanger is a finned tube heat exchanger, and the make-up air heat exchanger is installed at the exhaust port of the steam oven.

3. The waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The fresh air preheater is a plate heat exchanger.

4. The waste heat recovery system for condensate from a steam oven according to claim 3, characterized in that: The plates of the plate heat exchanger are made of 304L stainless steel.

5. The waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The design pressure of the fresh air preheater is ≥0.6MPa.

6. The waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The high-temperature water pump is a centrifugal pump with a temperature resistance of ≥120℃.

7. A waste heat recovery system for condensate from a steam oven according to claim 6, characterized in that: The high-temperature water pump is equipped with a variable frequency speed control device, which is used to automatically adjust the flow rate of the high-temperature water pump according to the water level of the high-temperature soft water tank.

8. A steam oven condensate waste heat recovery system according to claim 1, characterized in that: The flash tank is a vertical pressure vessel.

9. A waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The flash tank is equipped with a steam-water separation baffle.

10. A waste heat recovery system for condensate from a steam oven according to claim 1, characterized in that: The flash tank is also equipped with a safety valve and a pressure gauge, which are located at the secondary steam outlet.

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