Urea pipeline heat tracing system using urea hydrolyzer hydrophobic heat tracing

Abstract

The utility model discloses a kind of urea pipeline heat tracing systems using urea hydrolyzer hydrophobic heat tracing, including urea hydrolyzer hydrophobic pipeline, urea solution storage tank and urea solution pipeline and urea solution delivery pump, urea hydrolyzer hydrophobic pipeline connects hydrolyzer hydrophobic export to hydrophobic tank, the urea outlet of urea solution storage tank is connected with the inlet of urea solution pipeline by urea solution delivery pump and is communicated, the urea hydrolyzer hydrophobic pipeline and urea solution pipeline outside commonly set with heat tracing pipeline, heat tracing pipeline is filled with heat-conducting silicone grease.The utility model has the advantages that 1. zero energy consumption: with the hydrophobic of urea hydrolyzer as heat source, heat tracing is carried out to urea solution pipeline, without additional energy source;2. low cost: save electric heat tracing band and supporting electrical equipment, investment reduces more than 40%;3. high reliability: no electrical component, low failure rate, simple maintenance;4. environmental protection: realize energy cascade utilization, reduce carbon emission.

Description

Technical Field

[0001] This utility model relates to the field of denitrification technology in coal-fired power plants, and in particular to a heat tracing device for urea solution pipelines in urea hydrolysis systems, specifically a system that uses the residual heat from the urea hydrolyzer to heat urea solution pipelines. Background Technology

[0002] Currently, for safety reasons, large-scale coal-fired power plants in China are gradually adopting urea hydrolysis systems to replace liquid ammonia as the denitrification reducing agent. To prevent urea solution from crystallizing and clogging pipelines during transportation, existing technologies mostly use electric heat tracing, but this method has the following drawbacks:

[0003] 1. High energy consumption: Electric heat tracing requires a continuous power supply, resulting in high operating costs;

[0004] 2. High investment: It requires electric heating tape, temperature control system and insulation layer, and the equipment is complex;

[0005] 3. Cumbersome maintenance: Electric heat tracing systems have a high failure rate and require regular maintenance.

[0006] The condensate (typically at 100-150℃) generated during the operation of urea hydrolyzers is usually discharged directly or recycled back to the boiler, and its waste heat is not effectively utilized. Therefore, there is an urgent need for an energy-saving, low-cost, and reliable heat tracing solution. Utility Model Content

[0007] This invention provides a urea pipeline heat tracing system that utilizes the hydrophobic heat tracing of a urea hydrolyzer. By recovering the hydrophobic waste heat, it replaces electric heat tracing and solves the problems of high energy consumption and large investment in existing technologies.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] A urea pipeline heat tracing system utilizing the urea hydrolyzer condensate drain pipe includes a urea hydrolyzer condensate drain pipe, a urea solution storage tank, a urea solution pipeline, and a urea solution delivery pump. The urea hydrolyzer condensate drain pipe connects the condensate outlet of the hydrolyzer to the condensate tank. The urea outlet of the urea solution storage tank is connected to the inlet of the urea solution pipeline via the urea solution delivery pump. A heat tracing pipe is fitted around both the urea hydrolyzer condensate drain pipe and the urea solution pipeline. The heat tracing pipe is filled with thermally conductive silicone grease, which is placed between the urea hydrolyzer condensate drain pipe and the urea solution pipeline.

[0010] A resistance thermometer I is installed on the urea hydrolyzer drainage pipe to measure the temperature of the high-temperature drainage from the urea hydrolyzer.

[0011] A resistance thermometer II is installed at the end of the urea solution pipeline to measure the temperature of the urea solution after it has been heated by high-temperature hydrophobic tracing.

[0012] Local urea hydrolyzer drain branch pipes are added to key nodes (such as elbows and valves) of the urea hydrolyzer drain pipe. The urea hydrolyzer drain branch pipes and urea hydrolyzer drain pipes located in the heat tracing pipe are distributed around the center of the urea solution pipe located in the heat tracing pipe. Thermal grease is also provided between the urea hydrolyzer drain branch pipes and the urea solution pipe. By setting the urea hydrolyzer drain branch pipes and the urea hydrolyzer drain pipes to be distributed around the urea solution pipe, the urea solution in the urea solution pipe can be heated evenly, improving the heat transfer efficiency.

[0013] It also includes a PID controller and an electric regulating valve. The electric regulating valve is installed on the urea hydrolyzer drain pipe. Both the resistance thermometer II and the electric regulating valve are electrically connected to the PID controller. The resistance thermometer II measures the temperature of the urea solution and transmits it to the PID controller. The PID controller feeds back the urea solution temperature to the electric regulating valve to dynamically adjust the drain flow rate.

[0014] The advantages of this utility model are:

[0015] 1. Zero energy consumption: The hydrophobic material of the urea hydrolyzer is used as a heat source to heat the urea solution pipeline, requiring no additional energy.

[0016] 2. Low cost: Eliminating the need for electric heating tape and related electrical equipment reduces investment by more than 40%;

[0017] 3. High reliability: No electrical components, low failure rate, and simple maintenance;

[0018] 4. Environmental friendliness: Enables cascaded energy utilization and reduces carbon emissions. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a urea pipeline heat tracing system that utilizes the hydrophobic heat tracing of a urea hydrolyzer according to this utility model.

[0021] Figure 2 This is a logic block diagram of the temperature control module in a urea pipeline heat tracing system that utilizes a urea hydrolyzer for hydrophobic heat tracing, according to this utility model.

[0022] Reference numerals in the attached diagram: 1. Drainage pipe of urea hydrolyzer; 2. Urea solution storage tank; 3. Urea solution pipe; 4. Urea solution transfer pump; 5. Heat tracing pipe; 6. Resistance thermometer I; 7. Resistance thermometer II; 8. Drainage branch pipe of urea hydrolyzer. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] like Figure 1 As shown, a urea pipeline heat tracing system utilizing the urea hydrolyzer condensate drain and heat tracing includes a urea hydrolyzer condensate drain pipe 1, a urea solution storage tank 2, a urea solution pipeline 3, and a urea solution delivery pump 4. The urea hydrolyzer condensate drain pipe 1 connects to the condensate drain outlet of the hydrolyzer to the condensate tank. The urea outlet of the urea solution storage tank 2 is connected to the inlet of the urea solution pipeline 3 via the urea solution delivery pump 4. A heat tracing pipe 5 is installed parallel to the outer surfaces of the urea hydrolyzer condensate drain pipe 1 and the urea solution pipeline 3. The heat tracing pipe 5 is filled with thermally conductive silicone grease, which is placed between the urea hydrolyzer condensate drain pipe 1 and the urea solution pipeline 3.

[0025] A resistance thermometer I6 is installed on the urea hydrolyzer drainage pipe 1 to measure the temperature of the high-temperature drainage from the urea hydrolyzer.

[0026] A resistance thermometer II7 is installed at the end of the urea solution pipeline 3 to measure the temperature of the urea solution after it has been heated by high temperature hydrophobic tracing.

[0027] The key nodes (such as elbows and valves) of the urea hydrolyzer drainage pipe 1 are equipped with local urea hydrolyzer drainage branch pipes 8. The urea hydrolyzer drainage branch pipes 8 and urea hydrolyzer drainage pipe 1 located in the heat tracing pipe 5 are distributed around the center of the urea solution pipe 3 located in the heat tracing pipe 5. Thermal grease is also provided between the urea hydrolyzer drainage branch pipes 8 and the urea solution pipe 3. By setting the urea hydrolyzer drainage branch pipes 8 and urea hydrolyzer drainage pipe 1, they can be distributed around the outer periphery of the urea solution pipe 3, so that the urea solution in the urea solution pipe 3 can be heated evenly and the heat transfer efficiency can be improved.

[0028] like Figure 2As shown, it also includes a PID controller and an electric regulating valve. The electric regulating valve is installed on the urea hydrolyzer drain pipe 1. The resistance thermometer II7 and the electric regulating valve are both electrically connected to the PID controller. The resistance thermometer II7 measures the temperature of the urea solution and transmits it to the PID controller. The PID controller feeds back the urea solution temperature to the electric regulating valve to dynamically adjust the drain flow rate.

[0029] Workflow:

[0030] High-temperature condensate from the urea hydrolyzer is transported through the urea hydrolyzer condensate pipe 1. At the same time, the urea solution transfer pump 4 operates, causing the urea solution in the urea solution storage tank 2 to enter the urea solution pipe 3 for transport. Since the urea hydrolyzer condensate pipe 1 and the urea solution pipe 3 are both fitted with a heat tracing pipe 5 at their parallel outer sections, the heat from the high-temperature condensate is transferred to the urea solution pipe 3 through the thermally conductive silicone grease in the heat tracing pipe 5 during the transport of the high-temperature condensate and the urea solution, thereby heating the solution in the urea solution pipe 3 and ensuring that the urea solution does not crystallize and block the pipe during the transport process.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A urea pipeline heat tracing system utilizing a urea hydrolyzer for hydrophobic heat tracing, characterized in that: The system includes a urea hydrolyzer drain pipe (1), a urea solution storage tank (2), a urea solution pipeline (3), and a urea solution delivery pump (4). The urea hydrolyzer drain pipe (1) connects the drain outlet of the hydrolyzer to the drain tank. The urea outlet of the urea solution storage tank (2) is connected to the inlet of the urea solution pipeline (3) via the urea solution delivery pump (4). A heat tracing pipe (5) is installed around the urea hydrolyzer drain pipe (1) and the urea solution pipeline (3). The heat tracing pipe (5) is filled with thermally conductive silicone grease and is placed between the urea hydrolyzer drain pipe (1) and the urea solution pipeline (3).

2. The urea pipeline heat tracing system utilizing the hydrophobic heat tracing of a urea hydrolyzer according to claim 1, characterized in that: A resistance thermometer I (6) is installed on the drainage pipe (1) of the urea hydrolyzer.

3. The urea pipeline heat tracing system utilizing the hydrophobic heat tracing of a urea hydrolyzer according to claim 2, characterized in that: A resistance thermometer II (7) is installed at the end of the urea solution pipeline (3).

4. The urea pipeline heat tracing system utilizing the hydrophobic heat tracing of a urea hydrolyzer according to claim 3, characterized in that: The key node of the urea hydrolyzer drainage pipe (1) is provided with a local urea hydrolyzer drainage branch pipe (8). The urea hydrolyzer drainage branch pipe (8) and the urea hydrolyzer drainage pipe (1) located in the heat tracing pipe (5) are distributed around the center of the urea solution pipe (3) located in the heat tracing pipe (5). Thermal grease is also provided between the urea hydrolyzer drainage branch pipe (8) and the urea solution pipe (3).

5. The urea pipeline heat tracing system utilizing the hydrophobic heat tracing of a urea hydrolyzer according to claim 4, characterized in that: It also includes a PID controller and an electric regulating valve.

6. The urea pipeline heat tracing system utilizing the hydrophobic heat tracing of a urea hydrolyzer according to claim 5, characterized in that: The electric regulating valve is installed on the urea hydrolyzer drain pipe (1), and the thermal resistance thermometer II (7) and the electric regulating valve are electrically connected to the PID controller.

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