A drain control system suitable for low load operation of long distance steam pipelines

Abstract

This invention discloses a condensate control system suitable for low-load operation of long-distance steam pipelines, relating to the field of control or regulation systems. It includes a steam pipeline, an insulation layer, and an optimized energy-saving condensate control device. The optimized energy-saving condensate control device is a combination of a thermostatic condensate valve assembly and a centralized drainage device. The centralized drainage device consists of a centralized condensate pipe, a water level measurement unit, a water level control unit, and an automatic regulating valve assembly. Through this device, the automatic drainage valve opens when the condensate level in the steam pipeline is high and closes when the condensate level is low, maintaining the condensate at the bottom of the steam pipeline at a reasonable level, maximizing the insulation effect of the condensate and increasing the steam flow rate, while ensuring that water hammer does not occur.

Description

Technical Field

[0001] This invention relates to the field of general control or regulation systems, specifically a condensate control system suitable for low-load operation of long-distance steam pipelines. Background Technology

[0002] Long-distance steam heating networks often experience condensation of saturated steam in distant pipelines during variable load operation, particularly pronounced at low loads, resulting in large condensate drain valve discharge. Currently, long-distance steam heating networks typically use mechanical condensate drain valves, which lead to high condensate discharge and heat loss at low loads. For example, a heating company's main steam heating pipeline to its branch pipe at the furthest user has a DN500 diameter, a length of 1500m, a pressure of 0.5MPa, and a temperature of 175℃. Operating at an inlet velocity of 20m / s, the flow rate can reach 50t / h. Operationally, the branch pipe operates at a low load of 15t / h, with a low flow velocity (inlet 7.5m / s) and minimal resistance loss, but a large temperature drop (29℃). This indicates that the branch pipe diameter is too large at low loads, causing excessive condensate heat loss. Therefore, implementing measures to reduce steam condensate loss in saturated steam pipes under such conditions is of significant practical value.

[0003] By optimizing the design of existing steam pipeline systems, correctly selecting steam traps, applying artificial intelligence monitoring and control technologies, and properly installing and debugging equipment, we can not only solve the above-mentioned problems and reduce energy consumption, but also help eliminate equipment safety hazards, improve overall production efficiency and energy utilization, and ultimately promote green and low-carbon development, and help achieve "carbon peak" and "carbon neutrality". Summary of the Invention

[0004] The purpose of this invention patent is to address the shortcomings of existing technologies by proposing a condensate control system suitable for low-load operation of long-distance steam pipelines.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a condensate control system suitable for low-load operation of long-distance steam pipelines, including a steam pipeline, an insulation layer, and an optimized energy-saving condensate control device. The optimized energy-saving condensate control device is composed of a thermostatic condensate valve group and a centralized drainage device. The centralized drainage device is composed of a centralized condensate pipe, a water level measurement unit, a water level control unit, and an automatic regulating valve group.

[0006] Thermostatic steam traps operate by sensing changes in fluid temperature. The temperature difference between steam and condensate, or between air and steam mixtures, causes the sensing element to deform or expand, opening and closing the valve core. They offer excellent air venting capability under low pressure. Thermostatic steam traps have a relatively large subcooling, typically between 15°C and 40°C. They utilize some of the sensible heat in the condensate, ensuring a constant supply of high-temperature condensate upstream of the valve, preventing steam leakage and resulting in significant energy savings. They are ideal steam traps for steam pipelines, heat tracing lines, small heating equipment, and other small heating devices with low temperature requirements.

[0007] The optimized condensate control system of this invention uses a thermostatic condensate valve. By adjusting the set temperature of the thermostatic condensate valve, the subcooling can be regulated. The subcooling regulation range should be controlled within the high subcooling range of 30℃ to 40℃ to reduce condensate discharge from steam pipes under low load and reduce pipe losses.

[0008] Furthermore, after the amount of water drained from the steam pipe is reduced, condensate remains at the bottom of the steam pipe. The high-temperature condensate has a heat-insulating effect on the steam. On the other hand, the steam flow path of the steam pipe is partially blocked, which can increase the steam flow rate.

[0009] Furthermore, the condensate level at the bottom of the steam pipe is controlled by a centralized drainage device. This device opens the automatic drainage valve group when the condensate level is high and closes the automatic drainage valve group when the condensate level is low, keeping the condensate at the bottom of the steam pipe at a reasonable level, maximizing the heat preservation effect of the condensate and increasing the steam flow rate, while ensuring that water hammer does not occur.

[0010] A condensate control system suitable for low-load operation of long-distance steam pipelines, characterized by the following steps for startup, normal operation, and shutdown:

[0011] Step 1: When the steam pipeline is put into operation, open the front and rear manual shut-off valves of n thermostatic condensate trap groups and the centralized drainage device to start the condensate drainage work, quickly remove the low-temperature water accumulated in the pipeline, and complete the start-up condensate drainage of the steam pipeline.

[0012] Step 2: After the steam pipeline is started and the condensate drain is completed, it begins operation. Due to the low load, the condensate volume is large. The n thermostatic condensate drain valve groups using high subcooling (reduced drainage volume) are insufficient to drain all the condensate. High-temperature condensate begins to accumulate at the bottom of the steam pipeline, and the water level gradually rises. When it reaches the high water level, the water level measuring unit outputs a water level signal to the water level control unit. The water level control unit then opens the automatic drain valve group by outputting a switch signal. At this time, the water level gradually drops. When the water level measuring unit detects the set low water level value, it then closes the automatic drain valve group by outputting a switch signal through the water level control unit. The automatic drain valve group operates in a cycle to maintain the condensate water level in the steam pipeline within the required reasonable water level range.

[0013] Step 3: When the steam pipeline stops working, close the front manual shut-off valve of n thermostatic condensate trap groups and one centralized drainage device.

[0014] Compared with existing technologies, this invention provides a condensate control system suitable for low-load operation of long-distance steam pipelines. The condensate level of the steam pipeline is controlled by a centralized drainage device. This device automatically opens the drain valve when the condensate level is high and closes it when the level is low, maintaining the condensate at the bottom of the steam pipeline at a reasonable level. This maximizes the heat preservation effect of the condensate and increases the steam flow rate, while preventing water hammer.

[0015] To reduce pipe losses during low-load operation of long-distance saturated steam pipelines, the steam pipeline's steam trap assemblies have been changed from conventional mechanical steam trap assemblies to thermostatic steam trap assemblies. The thermostatic steam trap assemblies are controlled by the drainage temperature. By adjusting the set temperature, the subcooling is regulated, with the subcooling range controlled within a high subcooling range of 30℃~40℃. This ensures that the steam pipeline can start draining and venting, and the high subcooling means that the thermostatic steam trap assemblies only begin draining at temperatures 30℃~40℃ below the saturation temperature, thus reducing the amount of water drained during low-load operation of the steam pipeline. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Explanation of reference numerals in the attached figures:

[0019] 1. Steam pipe; 2. Insulation layer; 3. Thermostatic steam trap assembly; 4. Centralized steam trap; 5. Water level measurement unit; 6. Water level control unit; 7. Automatic drain valve assembly. Detailed Implementation

[0020] To make the technical means, creative features, achieved objectives, and effects of this invention readily understandable, the invention is further described below in conjunction with specific embodiments. The invention will be further described below with reference to the accompanying drawings. The described embodiments are merely a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] It should be noted that all directional indicators (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0022] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0023] like Figure 1 As shown, a condensate control system suitable for low-load operation of long-distance steam pipelines includes a steam pipeline 1, an insulation layer 2, and an optimized energy-saving condensate control device; the optimized energy-saving condensate control device consists of a thermostatic condensate valve group 3 and a centralized drainage device; the centralized drainage device consists of a centralized condensate pipe 4, a water level measuring unit 5, a water level control unit 6, and an automatic regulating valve group 7.

[0024] The selected length of steam pipe 1 (this length range includes n steam trap groups, n≥1, where n is a non-zero natural number) satisfies the requirement that the condensate volume of this section of pipe matches the drainage volume of a centralized drainage device. In practical applications, it is used in the range of 200m to 1km. Most of the condensate from steam pipe 1 is discharged through the centralized drainage device, which facilitates the centralized collection and reuse of condensate.

[0025] To reduce pipe losses during low-load operation of long-distance saturated steam pipelines, the steam trap assembly of steam pipeline 1 was changed from a conventional mechanical steam trap assembly to a thermostatic steam trap assembly 3. The thermostatic steam trap assembly 3 is controlled by the drainage temperature. By adjusting the set temperature, the subcooling is regulated. The subcooling regulation range should be controlled within the high subcooling range of 30℃~40℃. This ensures that the steam pipeline can start draining and venting, and the high subcooling means that the thermostatic steam trap assembly 3 only starts draining 30℃~40℃ below the saturation temperature, thus reducing the amount of water drained from steam pipeline 1 during low-load operation.

[0026] The centralized drain pipe 4 is located downstream of the steam pipe 1. The condensate at the bottom of the steam pipe 1 flows downwards along the steam flow direction, maximizing the heat preservation effect of the condensate on the steam. The upper end of the centralized drain pipe 4 connects to the top of the steam pipe 1, and the lower end connects to the bottom of the steam pipe 1. A water level measuring unit 5 is installed inside the centralized drain pipe 4. The water level measuring unit 5 can display the water level and output a water level signal to the water level control unit 6. The water level control unit 6 controls the opening and closing of the automatic regulating valve group 7 to maintain the condensate water level in the steam pipe 1 within the required range. The required water level range needs to be determined through on-site testing to ensure that water hammer is not caused, and that sufficient water is retained at the bottom of the pipe to ensure the heat preservation effect of the condensate on the steam.

[0027] A condensate control system suitable for low-load operation of long-distance steam pipelines, characterized by the following steps for startup, normal operation, and shutdown:

[0028] Step 1: When steam pipeline 1 is put into operation, open the front and rear manual shut-off valves of n thermostatic condensate trap groups 3 and a centralized drainage device to start the condensate drainage work, quickly remove the low-temperature water accumulated in the pipeline, and complete the start-up condensate drainage of steam pipeline 1.

[0029] Step 2: Steam pipe 1 is put into operation after the start-up drainage is completed. Due to the low load, the condensate volume is large. The n thermostatic condensate traps 3 using high subcooling (reduced drainage volume) are insufficient to drain all the condensate. High-temperature condensate begins to accumulate at the bottom of steam pipe 1, and the water level gradually rises. When the high water level is reached, the water level measuring unit 5 outputs a water level signal to the water level control unit 6. The water level control unit 6 opens the automatic drain valve group 7 by outputting a switch signal. At this time, the water level gradually drops. When the water level measuring unit 5 detects the set low water level value, it closes the automatic drain valve group 7 by outputting a switch signal through the water level control unit 6. The automatic drain valve group 7 operates in a cycle to maintain the condensate water level of steam pipe 1 within the required reasonable water level range.

[0030] Step 3: When steam pipe 1 stops working, close the n thermostatic condensate trap groups 3 and the front manual shut-off valve of the centralized drainage device.

[0031] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A condensate control system suitable for low-load operation of long-distance steam pipelines, characterized in that, It includes a steam pipe (1), an insulation layer (2), and an optimized energy-saving drainage control device. The optimized energy-saving drainage control device is composed of a thermostatic drainage valve group (3) and a centralized drainage device. The centralized drainage device consists of a centralized drainage pipe (4), a water level measuring unit (5), a water level control unit (6), and an automatic drainage valve group (7).

2. A condensate control system suitable for low-load operation of long-distance steam pipelines according to claim 1, characterized in that, The thermostatic steam trap assembly (3) uses a thermostatic steam trap with high subcooling. By adjusting the set temperature of the thermostatic steam trap, the subcooling can be adjusted. The subcooling adjustment range is controlled at 30℃~40℃. The high subcooling means that the thermostatic steam trap assembly (3) only starts to drain water when it is 30℃~40℃ below the saturation temperature.

3. A condensate control system suitable for low-load operation of long-distance steam pipelines according to claim 1, characterized in that, The steam pipe (1) contains n thermostatic steam trap groups (3), n≥1, where n is a non-zero natural number. The length of the selected steam pipe (1) must satisfy the requirement that the condensate volume of the steam pipe (1) is equal to the sum of the drainage volume of a centralized drainage device and the drainage volume of the n thermostatic steam trap groups (3). Most of the condensate of the steam pipe (1) is discharged through the centralized drainage device.

4. A condensate control system suitable for low-load operation of long-distance steam pipelines according to claim 1, characterized in that, The length of the steam pipeline (1) is 200m to 1km.

5. A condensate control system suitable for low-load operation of long-distance steam pipelines according to claim 1, characterized in that, The condensate level at the bottom of the steam pipe (1) is controlled by the centralized drainage device. When the condensate level of the steam pipe (1) is high, the automatic drainage valve group (7) is opened, and when the condensate level is low, the automatic drainage valve group (7) is closed, so as to keep the condensate level at the bottom of the steam pipe (1) at a reasonable level.

6. A condensate control system suitable for low-load operation of long-distance steam pipelines according to claim 1, characterized in that, The centralized drain pipe (4) is located downstream of the steam pipe (1). The condensate at the bottom of the steam pipe (1) flows downstream along the steam flow direction. The upper end of the centralized drain pipe (4) is connected to the top of the steam pipe (1), and its lower end is connected to the bottom of the steam pipe (1).

7. A method for controlling condensate drainage in long-distance steam pipelines under low load, characterized in that, The condensate control system for low-load operation of long-distance steam pipelines as described in any one of claims 1-6 has the following control principle: Step 1: When the steam pipeline (1) is put into operation, open the front and rear manual shut-off valves of n thermostatic condensate valve groups (3) and a centralized drainage device to start the condensate drainage work, quickly remove the low-temperature water in the pipeline, and complete the start-up condensate drainage of the steam pipeline (1). Step 2: The steam pipe (1) is put into operation after the start-up drainage is completed. Due to the large amount of condensate caused by the low load, the n thermostatic condensate valve groups (3) with high subcooling (reduced drainage volume) are not enough to drain all the condensate. High temperature condensate begins to accumulate at the bottom of the steam pipe (1), and the water level gradually rises. When the water level reaches the high water level, the water level measuring unit (5) outputs a water level signal to the water level control unit (6). The water level control unit (6) opens the automatic drain valve group (7) by outputting a switch signal. At this time, the water level gradually drops. When the water level measuring unit (5) detects the set low water level value, it closes the automatic drain valve group (7) by outputting a switch signal through the water level control unit (6). The automatic drain valve group (7) operates in a cycle. Step 3: When the steam pipe (1) stops working, close the front manual shut-off valve of n thermostatic condensate traps (3) and a centralized drainage device.

Images