A control device for regulating process temperature in a steam heating system

Abstract

The utility model relates to control device technical field, concretely relates to a control device for adjusting steam heating system process temperature, including heat exchanger, the shell side of heat exchanger is equipped with steam inlet and condensate outlet, and the pipe side is equipped with process medium inlet and outlet, wherein, on the pipeline of condensate outlet, be equipped with a for establishing bag type structure of liquid seal, through the bag type structure makes heat exchanger realize low liquid level vacuum operation, and outlet bag type realizes full liquid level operation. Through simple structure reconstruction, establish bag type liquid seal, actively change heat exchanger shell side into vacuum operation state, provide basic solution for overcoming the control hysteresis, insufficient precision, high energy consumption and operation flexibility difference existing in traditional steam temperature control.

Description

Technical Field

[0001] This utility model relates to the field of control device technology, specifically to a control device for adjusting the process temperature of a steam heating system. Background Technology

[0002] In process industries such as chemical, petroleum, and pharmaceutical, steam heaters are widely used key equipment for heating process media or for precise temperature control. Traditional temperature control schemes typically achieve this by adjusting the steam flow rate or pressure entering the heat exchanger shell side. Specifically, this involves installing a regulating valve on the steam pipeline and dynamically adjusting the valve opening based on temperature feedback from the process media outlet.

[0003] However, the following problems exist: 1. Control lag and large fluctuations: Due to the large volume space on the steam side, when the operating conditions change, it takes a long time for the regulating valve to affect the temperature of the process medium, resulting in slow system response, overshoot or oscillation in temperature control, and difficulty in achieving precise and stable control.

[0004] 2. Low energy efficiency: In order to ensure the heat demand under the most unfavorable operating conditions, the steam regulating valve usually needs to maintain a large opening, which leads to insufficient utilization of steam pressure, a large loss of high-quality energy, and serious energy waste.

[0005] 3. Poor operational flexibility: When it is necessary to control the temperature of the process medium at a low level, the traditional method can only achieve this by significantly closing the steam valve. This can easily lead to an excessive pressure difference across the valve, resulting in flashing, cavitation, damage to the valve, and generating loud noise, thus limiting the range of operating condition adjustments.

[0006] 4. The negative pressure effect cannot be utilized. When the steam heat exchange system is shut down or at low load, the shell side condensation will cause a vacuum to form inside. However, traditional systems lack the design to effectively utilize this vacuum. They often need to introduce air through a vacuum breaking valve, thus missing the opportunity to improve heat transfer and save energy by utilizing negative pressure. Utility Model Content

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a control device for regulating the process temperature of a steam heating system. This device addresses the problems of lag and large fluctuations in traditional equipment control. Due to the large volume space on the steam side, the regulating valve needs a long time to affect the temperature of the process medium when the operating conditions change, resulting in slow system response, overshoot or oscillation in temperature control, difficulty in achieving precise and stable control, and low energy efficiency. To ensure the heat demand under the most unfavorable operating conditions, the steam regulating valve usually needs to maintain a large opening, resulting in insufficient utilization of steam pressure, significant loss of a large amount of high-quality energy, and serious energy waste.

[0008] One embodiment of the present invention provides a control device for adjusting the process temperature of a steam heating system, including a heat exchanger, wherein the shell side of the heat exchanger is provided with a steam inlet and a condensate outlet, and the tube side is provided with a process medium inlet and an outlet. The condensate outlet pipe is equipped with a bag-shaped structure for establishing a liquid seal, which enables the shell side of the heat exchanger to operate under low liquid level vacuum.

[0009] This invention relates to a control device for regulating the process temperature of a steam heating system. Through a bag-shaped structure, the shell side of the heat exchanger achieves low-level vacuum operation. By simply modifying the structure and establishing a bag-shaped liquid seal, the heat exchanger shell side is actively switched to a low-level vacuum operating state, providing a fundamental solution to overcome the control lag, insufficient accuracy, high energy consumption, and poor operational flexibility inherent in traditional steam temperature control.

[0010] In one embodiment, the bag-shaped structure is formed by a U-shaped or V-shaped bend created by the sinking of the condensate pipe.

[0011] In one embodiment, the lowest point of the bag-shaped structure is provided with a drain outlet or a sewage outlet, and is equipped with a corresponding valve.

[0012] In one embodiment, a condensate outlet pipe is further connected in series with a condensate drain valve assembly and a check valve at the rear end of the bag-shaped structure.

[0013] In one embodiment, the steam trap assembly is a thermostatic or thermodynamic steam trap.

[0014] In one embodiment, a steam pressure regulating valve is provided on the steam inlet pipeline to regulate the steam flow rate or pressure entering the shell side according to the temperature of the process medium outlet.

[0015] In one embodiment, the device further includes a temperature sensor and a controller. The temperature sensor is disposed on the pipeline at the outlet of the process medium and is used to detect the temperature and transmit a signal to the controller. The controller outputs a control signal to the steam pressure regulating valve.

[0016] In one embodiment, the device further includes a vacuum breaker valve disposed at the top of the shell side of the heat exchanger or on a pipe connected to the shell side.

[0017] In one embodiment, the establishment of the bag-shaped structure enables the heat exchanger shell side to form a negative pressure condition during operation.

[0018] In one embodiment, the process medium is ethylene.

[0019] The control device for adjusting the process temperature of a steam heating system provided by the above technical solution has the following beneficial effects: 1. By establishing a "bag-type" liquid seal structure on the condensate pipeline, the shell side of the heat exchanger is actively switched to a low-liquid-level vacuum operating state. The phase change heat transfer in the shell side changes from being dominated by high-pressure steam condensation to being dominated by negative-pressure steam condensation. The negative-pressure steam generated by the "bag-type" liquid seal significantly reduces the steam temperature. Therefore, the outlet temperature of the process medium (ethylene) becomes extremely insensitive to fluctuations in steam pressure, fundamentally eliminating the temperature oscillation and hysteresis problems that are difficult to solve in traditional control methods.

[0020] 2. The low-level vacuum operation established through the "bag-type" liquid seal reduces the shell-side steam temperature, avoiding the overheating of the process side caused by steam superheating in traditional methods. More importantly, the system can stably maintain a high vacuum (negative pressure environment) inside the shell. The saturation temperature of water decreases with decreasing pressure, meaning that under lower negative pressure, the shell-side hot water can boil and vaporize at a lower temperature, thus significantly reducing the effective heat transfer temperature difference while keeping the steam inlet pressure constant. This "self-inhibition" effect allows the system to meet the same process heating requirements with less steam consumption, achieving better energy saving and consumption reduction.

[0021] 3. This invention, by adjusting the height of the "bag-type" liquid seal or by fine-tuning the steam regulating valve, can flexibly establish and maintain different vacuum levels in the shell side. This allows for wide-range, smooth adjustment of the process medium outlet temperature without changing the steam source pressure. For example, the ethylene temperature can be stabilized at any set value far from the saturation temperature at that steam pressure. This provides great flexibility for production optimization and solves the problems of difficult adjustment and easy equipment damage under low load and low temperature conditions in traditional solutions.

[0022] 4. Low-level vacuum operation extends the equipment's service life. Simultaneously, system start-up and shutdown are smoother, reducing thermal stress shocks caused by sudden temperature changes. The negative pressure environment formed in the shell side is stable and controllable, avoiding the risk of equipment instability that may occur due to unexpected high vacuum in traditional systems.

[0023] 5. This utility model does not require complex and expensive high-precision control valves or additional equipment. Its core "bag-shaped" structure can be achieved by simply modifying the existing pipeline layout, or can be easily integrated into the design of new equipment. It is convenient to operate and maintain, and is suitable for energy-saving and efficiency-enhancing technology transformation of existing devices. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the pipeline connection of this utility model; Figure 2 This is a pipeline flow diagram of this utility model.

[0026] The markings in the diagram are explained as follows: 100. Heat exchanger; 200. Steam inlet; 300. Condensate outlet; 400. Bag-type structure; 500. Drain valve assembly; 510. Inspection valve; 600. Steam pressure regulating valve; 700. Vacuum breaker valve; 800. Temperature sensor. Detailed Implementation

[0027] The above detailed description is a specific description of a feasible embodiment of the present utility model. This embodiment is not intended to limit the patent scope of the present utility model. All equivalent implementations or modifications that do not depart from the so-called equivalent implementations or modifications of the present utility model should be included in the patent scope of this case.

[0028] Combination Figures 1 to 2 As shown, one embodiment of the present invention provides a control device for adjusting the process temperature of a steam heating system, including a heat exchanger 100. The shell side of the heat exchanger 100 is provided with a steam inlet 200 and a condensate outlet 300, and the tube side is provided with a process medium inlet and an outlet. In particular, a bag-shaped structure 400 for establishing a liquid seal is provided on the pipeline of the condensate outlet 300, through which the shell side of the heat exchanger 100 can achieve low liquid level vacuum operation.

[0029] This invention discloses a control device for regulating the process temperature of a steam heating system. Through a bag-type structure 400, the shell side of the heat exchanger 100 achieves low-liquid-level vacuum operation. By simply modifying the structure and establishing a bag-type liquid seal, the heat exchanger 100 shell side is actively switched to a low-liquid-level vacuum operating state, fundamentally changing the heat transfer mechanism. This provides a basic solution to overcome the control lag, insufficient accuracy, high energy consumption, and poor operational flexibility inherent in traditional steam temperature control.

[0030] In one embodiment, the bag-shaped structure 400 is formed by a U-shaped or V-shaped bend created by the sinking of the condensate pipe.

[0031] In this embodiment, the specific form of the bag structure 400 is further defined. It adopts a U-shaped or V-shaped bend, which is simple in structure and does not require complex internal components. It can be formed by the natural sinking of the pipe. It is convenient for construction and modification, low in cost and highly reliable. The liquid seal effect is stable and not easy to fail.

[0032] In one embodiment, the lowest point of the bag structure 400 is provided with a drain outlet or a sewage outlet, and is equipped with a corresponding valve.

[0033] In this embodiment, a drain port or sludge outlet is added to improve the maintainability and operational flexibility of the system. The drain port can completely drain the accumulated liquid when the system is shut down to prevent equipment corrosion or freezing. It can also be used to remove dirt that may accumulate in the early stages of operation, ensuring the purity of the liquid seal and heat exchange efficiency, and extending the service life of the equipment.

[0034] In one embodiment, a condensate outlet 300 is connected in series with a drain valve assembly 500 and a check valve 510 at the rear end of the bag structure 400 on the pipeline.

[0035] In this embodiment, the configuration of the steam trap assembly 500 and the inspection valve 510 is defined, enabling the automatic, continuous, and reliable operation of the system. The steam trap can automatically block steam and drain water, ensuring the stable existence of the liquid seal, while the inspection valve 510 can prevent pressure fluctuations or fluid backflow in the condensate pipe network from interfering with the shell-side vacuum and the liquid seal, thus ensuring the stability of the core control strategy.

[0036] In one embodiment, the steam trap assembly 500 is a thermostatic or thermodynamic steam trap.

[0037] In this embodiment, the types of steam traps are further clarified, and the performance of the system under different operating conditions is optimized. Thermostatic steam traps have good energy-saving effects and are suitable for demanding operating conditions. Thermodynamic steam traps have good resistance to water hammer and back pressure, are durable and low in cost. Selecting the type according to specific needs can further improve the energy efficiency and reliability of the device.

[0038] In one embodiment, a steam pressure regulating valve 600 is provided on the pipeline of the steam inlet 200 to regulate the steam flow rate or pressure entering the shell side according to the temperature of the process medium outlet.

[0039] In this embodiment, a steam pressure regulating valve 600 is introduced and linked to the temperature, providing a refined secondary regulation method. Under the main control framework established by the bag-type structure 400, the process temperature can be "fine-tuned" by adjusting the steam pressure, so that the temperature control accuracy reaches a higher level, achieving a perfect combination of "coarse adjustment" (bag-type liquid seal) and "fine adjustment" (steam valve).

[0040] In one embodiment, the device further includes a temperature sensor 800 and a controller. The temperature sensor 800 is disposed on the pipeline at the outlet of the process medium and is used to detect the temperature and transmit a signal to the controller. The controller outputs a control signal to the steam pressure regulating valve 600.

[0041] In this embodiment, an automated control system was added, achieving fully automatic intelligent control and significantly reducing manual intervention. The system can monitor the outlet temperature in real time and automatically and quickly adjust the steam valve, ensuring absolute stability of product quality and freeing up labor, making it a key component of a modern smart factory.

[0042] In one embodiment, the device further includes a vacuum breaker valve 700, which is disposed at the top of the shell side of the heat exchanger 100 or on a pipe connected to the shell side.

[0043] In this embodiment, a vacuum breaker valve 700 is added to improve the safety of the system. When the system is shut down for maintenance, the valve can effectively break the shell-side vacuum, preventing external equipment (such as pumps) from being damaged by the siphon effect. At the same time, it avoids the risk of air being sucked into the system during maintenance, providing an important guarantee for safe operation and maintenance.

[0044] In one embodiment, the establishment of the bag-shaped structure 400 causes the shell side of the heat exchanger 100 to form a negative pressure condition during operation.

[0045] In this embodiment, the technical effect of creating a negative pressure condition in the shell side is defined, which brings about the core energy-saving advantage. The negative pressure in the shell side leads to a decrease in the saturation temperature of the water, which allows the system to maintain effective heat transfer with lower steam consumption, maximizes thermal energy utilization, and thus improves economic efficiency.

[0046] In one embodiment, the process medium is ethylene.

[0047] In this embodiment, the process medium is limited to ethylene, highlighting its outstanding value in a specific key area. Ethylene production is the leading industry in petrochemicals, and its cracking and separation processes are extremely sensitive to temperature. This invention can provide stable, accurate, and energy-saving temperature control for ethylene plants.

[0048] The working principle of this utility model: The required steam pressure is calculated by simulating the temperature and pressure curve of the steam using simulation software, and the potential energy corresponding to the height of the heat exchanger is also calculated. By closing the steam inlet valve, the steam pressure is lowered to below -55 kPag, and the temperature will be lowered to below 60°C. A condensate level is established through the condensate pipeline, and the condensate is drained into the trench using thermosiphon, with the condensate drained at the bottom bend (e.g., at the bottom bend of the pipe). Figure 1 (As shown) Establish a bag shape to prevent gas backflow at the pipe outlet from damaging the vacuum level.

[0049] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made using the paper parts and drawings of the present utility model under the inventive concept of the present utility model, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present utility model.

Claims

1. A control device for adjusting the process temperature of a steam heating system, characterized in that, The device includes a heat exchanger (100), wherein the shell side of the heat exchanger (100) is provided with a steam inlet (200) and a condensate outlet (300), and the tube side is provided with a process medium inlet and an outlet; In the pipeline of the condensate outlet (300), there is a bag-shaped structure (400) for establishing a liquid seal, through which the shell side of the heat exchanger (100) can achieve low liquid level vacuum operation.

2. The control device for adjusting the process temperature of a steam heating system according to claim 1, characterized in that, The bag-shaped structure (400) is formed by a U-shaped or V-shaped bend created by the sinking of the condensate pipe.

3. The control device for adjusting the process temperature of a steam heating system according to claim 2, characterized in that, The lowest point of the bag-shaped structure (400) is provided with a drain outlet or a sewage outlet, and is equipped with a corresponding valve.

4. The control device for adjusting the process temperature of a steam heating system according to claim 1, characterized in that, On the pipeline of the condensate outlet (300), a condensate trap assembly (500) and a check valve (510) are connected in series at the rear end of the bag structure (400).

5. A control device for adjusting the process temperature of a steam heating system according to claim 4, characterized in that, The steam trap assembly (500) is a thermostatic or thermodynamic steam trap.

6. A control device for adjusting the process temperature of a steam heating system according to claim 1, characterized in that, The steam inlet (200) is equipped with a steam pressure regulating valve (600) to regulate the steam flow rate or pressure entering the shell side according to the temperature of the process medium outlet.

7. A control device for adjusting the process temperature of a steam heating system according to claim 6, characterized in that, The device also includes a temperature sensor (800) and a controller. The temperature sensor (800) is installed on the pipeline at the outlet of the process medium to detect the temperature and transmit a signal to the controller. The controller outputs a control signal to the steam pressure regulating valve (600).

8. A control device for adjusting the process temperature of a steam heating system according to claim 5, characterized in that, The device also includes a vacuum breaker valve (700), which is disposed at the top of the shell side of the heat exchanger (100) or on a pipe connected to the shell side.

9. A control device for adjusting the process temperature of a steam heating system according to claim 5, characterized in that, The establishment of the bag-type structure (400) enables the shell side of the heat exchanger (100) to form a negative pressure condition during operation.

10. A control device for adjusting the process temperature of a steam heating system according to claim 5, characterized in that, The process medium is ethylene.

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