Exhaust natural convection condensation system of open type condensation water recovery device

Abstract

The invention relates to the technical field of energy conservation of industrial steam systems, in particular to an exhaust natural convection condensation system of an open type condensation water recovery device. Comprising an air-cooling heat exchanger, a water collecting tank and a condensate pump, the water collecting tank is provided with a saturated condensed water inlet pipeline and a condensed water outlet pipeline; an inlet of the air cooling heat exchanger is communicated with the steam space of the water collecting tank and is used for receiving and condensing flash steam from the water collecting tank; the air cooling heat exchanger is provided with an exhaust port used for exhausting uncondensed gas to the atmosphere. And the condensate pump is connected to a condensate outlet pipeline of the water collecting tank. The advantages of simple structure, low cost, safety and reliability of an open system can be reserved, visual and noise pollution can be effectively eliminated, and the heat energy recovery efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of energy-saving technology for industrial steam systems, specifically to an exhaust gas natural convection condensation system for an open condensate recovery device. Background Technology

[0002] In industrial production, steam is widely used as an important heat source, and the condensate formed after it releases heat has considerable value in terms of heat and water resources. Recovering condensate can significantly reduce boiler fuel consumption, lower water treatment costs, and avoid the discharge of high-temperature wastewater, thus becoming a key aspect of energy conservation and emission reduction for enterprises.

[0003] Currently, condensate recovery mainly employs two forms: open systems and closed systems. Traditional open condensate recovery devices are the most widely used due to their simplicity and low investment cost, making them particularly suitable for low-flow, low-pressure steam systems. However, open systems require atmospheric vents to discharge flash steam and non-condensable gases, leading to three significant problems: first, high-temperature steam condenses rapidly upon encountering cold air, producing a visually polluting "white smoke" phenomenon; second, direct steam discharge generates considerable noise; and third, a large amount of heat-containing steam is directly released into the atmosphere, resulting in energy waste.

[0004] To address these issues, closed-loop condensate recovery systems have emerged. These systems recover condensate through sealed pipelines, avoiding the direct emission of "white smoke" and steam heat. However, closed-loop systems have inherent drawbacks: firstly, they require pressure vessels, safety valve assemblies, and other components, resulting in high initial investment costs, typically more than double that of open systems; secondly, non-condensable gases tend to accumulate within the system, potentially leading to abnormal pressure and increasing the complexity and risk of operation and maintenance; and thirdly, the presence of the pressure vessel itself poses a potential safety hazard. Therefore, for many small and medium-sized or low-pressure steam systems, the cost-effectiveness of retrofitting with a closed-loop system is extremely low. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides an exhaust gas natural convection condensation system for an open condensate recovery device, which retains the advantages of open systems such as simple structure, low cost, and safety and reliability, while effectively eliminating visual and noise pollution and improving heat recovery efficiency.

[0006] To achieve the above objectives, the present invention employs the following technical solution: An open-type condensate recovery device with exhaust gas natural convection condensation system includes an air-cooled heat exchanger, a collection tank, and a condensate pump; the collection tank is provided with a saturated condensate inlet pipe and a condensate outlet pipe; the inlet of the air-cooled heat exchanger is connected to the steam space of the collection tank for receiving and condensing flash steam from the collection tank; the air-cooled heat exchanger is provided with an exhaust port for discharging uncondensed gas to the atmosphere; and the condensate pump is connected to the condensate outlet pipe of the collection tank.

[0007] Furthermore, the exhaust port is a vent pipe connected to the outlet of the air-cooled heat exchanger.

[0008] Furthermore, a silencer is provided on the vent pipe.

[0009] Furthermore, the muffler has a porous diffusion structure.

[0010] Furthermore, the air-cooled heat exchanger is a finned tube heat exchanger, with its heat exchange tubes arranged horizontally and connected via U-shaped elbows; the installation height of the air-cooled heat exchanger is higher than that of the water collection tank.

[0011] Furthermore, the tube bundles of the finned tube heat exchanger are arranged in a staggered or linear pattern.

[0012] Furthermore, the base tube and fins of the finned tube heat exchanger are made of steel, stainless steel, copper, or aluminum.

[0013] Furthermore, the condensate pump is a fluid power pump and is connected to a power medium inlet pipe.

[0014] Furthermore, it also includes an emergency pressure relief valve, which is installed in the water collection tank or on the pipeline connected to it.

[0015] Furthermore, the system is suitable for processing steam condensate with a pressure ≤1.6MPa and a temperature ≤250℃.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Heat recovery efficiency is significantly improved, and energy waste is fundamentally eliminated. Compared to traditional open systems that directly discharge large amounts of flash steam into the atmosphere, resulting in complete heat energy waste, this invention uses an air-cooled heat exchanger in the exhaust path to force the high-temperature flash steam to condense before discharge, with the condensate flowing back into the system. This process essentially recovers the heat energy (latent heat of vaporization) lost in the form of waste gas in traditional open systems. Most of the steam is condensed into liquid water and returned, retaining its heat within the system. This allows the actual condensate recovery rate and total heat recovery rate to approach the level of closed systems, fundamentally solving the problem of heat energy waste in traditional open systems.

[0017] 2. Visual and noise pollution have been effectively controlled. Traditional open-loop systems emit high-temperature steam that condenses upon cooling, forming "white smoke" accompanied by jet noise. This invention utilizes the condensation effect of an air-cooled heat exchanger to significantly reduce the temperature and steam content of the exhaust gas, eliminating the physical conditions for "white smoke" formation at its source. Simultaneously, a silencer 5 is installed on the subsequent vent pipe, employing porous diffusion structures to reduce noise in the exhaust airflow. The combination of these two measures results in emissions with no visible white smoke and a significantly reduced noise level, resolving the negative impacts on the plant environment and personnel.

[0018] 3. The system boasts excellent energy and space efficiency, with extremely low operating costs. The core heat exchange process of this invention relies on a combination of natural air convection and a finned-tube heat exchanger. The finned-tube structure greatly expands the heat transfer area per unit volume, enhancing air-side heat exchange and thus achieving efficient condensation within a limited space, eliminating the need for energy-consuming equipment such as fans and water pumps. The entire condensation process consumes no electricity or other external energy, resulting in near-zero system operating costs. Simultaneously, the compact finned-tube design saves installation space, achieving a balance between high efficiency and small size.

[0019] 4. High safety and reliability, easy maintenance This invention inherits the fundamental characteristic of open systems, which are open to the atmosphere. The internal pressure of the system remains close to atmospheric pressure, fundamentally avoiding the pressure accumulation and associated explosion risks that can occur in completely sealed closed systems. Furthermore, the air-cooled heat exchanger used has a simple structure with no moving parts, resulting in a low failure rate. Even in abnormal situations, the emergency pressure relief valve provides additional safety protection. Maintenance of the entire system primarily focuses on routine inspections, with a complexity and cost far lower than that of closed pressure vessel systems that require periodic calibration of safety valves and pressure monitoring.

[0020] 5. Low renovation cost, high return on investment, and wide applicability. The essence of this invention is to connect an air-cooled condensing unit in series with the vent pipe of a traditional open system. This solution does not require replacing the original core equipment such as the water tank and water pump, nor does it require adding pressure vessels, complex control and safety relief systems as in the case of converting to a closed system. This low-cost modification characteristic makes this invention particularly suitable for energy-saving upgrades of existing open systems, or as a cost-effective preferred solution in new projects. It has broad application prospects in almost all industries that use steam, such as chemical, power, food, and pharmaceutical industries.

[0021] In summary, this invention retains the core advantages of open systems, such as low cost, atmospheric pressure safety, and simple structure. At the same time, through natural convection condensation technology, it incorporates the key advantages of closed systems in terms of efficient heat recovery and elimination of environmental pollution, and successfully avoids the inherent disadvantages of closed systems, such as high investment costs, pressure safety hazards, and complex maintenance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure and process principle of the present invention.

[0023] The markings in the diagram are: 1. Air-cooled heat exchanger; 2. Water collection tank; 3. Condensate pump; 4. Vent pipe; 5. Silencer; 6. Emergency pressure relief valve; 7. Condensate outlet pipe; 8. Power medium inlet pipe; 9. Saturated condensate inlet pipe. Detailed Implementation

[0024] The embodiments of the present invention are described in detail below. To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and does not constitute any limitation on the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0026] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In the description of this invention, it should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0029] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0030] Example like Figure 1 As shown, this embodiment provides an exhaust natural convection condensation system for an open condensate recovery device. This system can efficiently recover condensate and its heat energy, while eliminating visual and noise pollution.

[0031] The system mainly includes a water collection tank 2, an air-cooled heat exchanger 1, a condensate pump 3, and related connecting pipes and accessories.

[0032] The water collection tank 2 is the core storage and buffer unit of the system. Its upper part is connected to a saturated condensate inlet pipe 9, used to receive high-temperature saturated condensate discharged from heat-using equipment (such as heat exchangers, dryers, etc.). Its lower part is connected to a condensate outlet pipe 7, used to transport the collected condensate to subsequent pipe networks or designated locations.

[0033] The air-cooled heat exchanger 1 is a key component in this invention for achieving steam condensation and heat recovery. In this embodiment, the air-cooled heat exchanger 1 is preferably a finned tube heat exchanger. Its inlet is directly connected to the steam space at the top of the water collection tank 2 via a pipe. When high-temperature saturated condensate enters the lower-pressure water collection tank 2 through the saturated condensate inlet pipe 9, a violent flash evaporation phenomenon occurs, generating a large amount of secondary steam. This flash steam, mixed with a small amount of non-condensable gases (such as air, CO2, etc.), automatically enters the air-cooled heat exchanger 1 under pressure differential.

[0034] The specific structure and installation requirements of the air-cooled heat exchanger 1 are as follows: Its heat exchange tubes are arranged horizontally, with multiple heat exchange tubes connected in series via U-shaped bends to form a continuous flow channel. This arrangement facilitates the smooth discharge of condensate under gravity.

[0035] Metal fins (such as aluminum fins or steel fins) are tightly wound or nested on the outer wall of the heat exchange tube, which greatly increases the effective heat transfer area outside the tube.

[0036] The installation height of the air-cooled heat exchanger 1 must be higher than that of the water collection tank 2. This design ensures that the liquid water condensed in the air-cooled heat exchanger 1 can automatically flow back to the water collection tank 2 or the inlet of the condensate pump 3 through the pipe under the action of gravity, while also facilitating the upward flow and final discharge of non-condensable gases.

[0037] The working process is as follows: Ambient air flows through the gaps between the finned tube bundles under natural convection. The high-temperature steam mixture flowing inside the tubes transfers its latent heat to the air through the tube walls and fins, and is itself condensed into liquid water. The condensate flows back along the pipes, thus realizing heat recovery.

[0038] An exhaust port is provided at the outlet end of the air-cooled heat exchanger 1 to discharge a small amount of non-condensable gas that has not been condensed. In this embodiment, the exhaust port is specifically implemented as a vertical vent pipe 4, the end of which leads to the atmosphere.

[0039] To further reduce airflow noise that may be generated during the emission process, a muffler 5 is installed on the vent pipe 4. The muffler 5 can preferably adopt a diffusion-type silencing structure with a perforated plate or sound-absorbing material inside, which can effectively control the exhaust noise at a low level.

[0040] The condensate pump 3 is connected to the condensate outlet pipe 7 of the collection tank 2. Its function is to pressurize and pump the condensate to the boiler room or other water-using points when the liquid level in the collection tank 2 reaches a set height (which can be controlled by a float valve or a liquid level sensor). In this embodiment, the condensate pump 3 is a fluid power pump, such as a steam power pump. For this purpose, the system also has a power medium inlet pipe 8, which is used to introduce the steam (or compressed air or other power gas) that drives the pump into the condensate pump 3. The exhaust steam or exhaust gas after the work is done is usually drawn back to the collection tank 2 and enters the air-cooled heat exchanger 1 together with the flash steam for treatment, forming a closed loop.

[0041] To ensure system safety, an emergency pressure relief valve 6 is installed on the water collection tank 2 or on the main steam pipeline directly connected to it. The valve's opening pressure setting is higher than the system's normal operating pressure but lower than the equipment's safe pressure limit. When the system experiences an abnormal pressure increase for any reason, the emergency pressure relief valve 6 will automatically open to release pressure and ensure equipment safety.

[0042] System workflow overview: 1. High-temperature saturated condensate enters the water collection tank 2 through pipe 9, and flash evaporation occurs due to pressure reduction.

[0043] 2. Flash steam and non-condensable gas enter the air-cooled heat exchanger 1, are cooled by the ambient air, and the steam condenses into water and flows back.

[0044] 3. Non-condensable gases are discharged into the atmosphere after being reduced in noise by vent pipe 4 and silencer 5.

[0045] 4. When the condensate level in the collection tank 2 rises to the set value, the condensate pump 3 is started (driven by the power medium through the pipeline 8).

[0046] 5. The condensate is pumped out by the condensate pump 3 through the condensate outlet pipe 7, completing the recycling process.

[0047] 6. Throughout the process, the emergency pressure relief valve 6 monitors the system pressure to provide safety assurance.

[0048] Special Note: The above description is merely one specific embodiment of the present invention. Within the scope of the core concept of the present invention (i.e., adding a natural convection air-cooled heat exchanger to the exhaust path of an open condensate recovery device), those skilled in the art can make various modifications and substitutions. For example: The condensate pump 3 can also be an electric centrifugal pump, in which case there is no need for the power medium inlet pipe 8.

[0049] The fin type, tube material (stainless steel, copper, etc.), and tube bundle arrangement (straight or staggered) of the air-cooled heat exchanger 1 can be selected and optimized according to specific operating conditions (such as medium composition, ambient temperature, and throughput).

[0050] The specific structure of the muffler 5 is not limited to the porous diffuser type; other mature muffler technologies may also be used.

[0051] The above description is only a part of the specific embodiments of the present invention. The scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An exhaust gas natural convection condensation system for an open-type condensate recovery device, characterized in that: It includes an air-cooled heat exchanger (1), a water collection tank (2), and a condensate pump (3); The water collection tank (2) is equipped with a saturated condensate inlet pipe (9) and a condensate outlet pipe (7); The inlet of the air-cooled heat exchanger (1) is connected to the steam space of the water collection tank (2) for receiving and condensing flash steam from the water collection tank (2); The air-cooled heat exchanger (1) is provided with an exhaust port for discharging uncondensed gas to the atmosphere; The condensate pump (3) is connected to the condensate outlet pipe (7) of the water collection tank (2).

2. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 1, characterized in that: The exhaust port is a vent pipe (4) connected to the outlet of the air-cooled heat exchanger (1).

3. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 2, characterized in that: A silencer (5) is provided on the vent pipe (4).

4. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 3, characterized in that: The silencer (5) has a porous diffusion structure.

5. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 1, characterized in that: The air-cooled heat exchanger (1) is a finned tube heat exchanger, with its heat exchange tubes set horizontally and connected by a U-shaped elbow; the installation height of the air-cooled heat exchanger (1) is higher than that of the water collection tank (2).

6. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 5, characterized in that: The tube bundles of the finned tube heat exchanger are arranged in a staggered or sequential manner.

7. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 5, characterized in that: The base tube and fins of the finned tube heat exchanger are made of steel, stainless steel, copper, or aluminum.

8. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 1, characterized in that: The condensate pump (3) is a fluid power pump and is connected to a power medium inlet pipe (8).

9. The exhaust gas natural convection condensation system of an open condensate recovery device according to claim 1, characterized in that: It also includes an emergency pressure relief valve (6), which is installed in the water collection tank (2) or on the pipeline connected to it.

10. The exhaust gas natural convection condensation system of an open condensate recovery device according to any one of claims 1-9, characterized in that: The system is suitable for processing steam condensate with a pressure ≤1.6MPa and a temperature ≤250℃.

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