Urea hydrolysis device
By using a heat exchanger in the urea hydrolysis unit to increase the temperature of the urea supplement solution, the problems of temperature drop and pressure fluctuation in the hydrolyzer caused by urea solution replenishment were solved, thereby improving ammonia production and system stability, and enhancing energy utilization.
Patent Information
- Application Number
- CN202520367170.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-03-04
AI Technical Summary
The replenishment of urea solution leads to a decrease in temperature inside the hydrolyzer, a decrease in ammonia production, and pressure fluctuations in the hydrolyzer, affecting the operation of the boiler denitrification system.
A heat exchanger is used to exchange heat between the high-temperature hydrolysate output from the hydrolyzer and the urea supplement solution, thereby increasing the temperature of the urea supplement solution, reducing temperature drop, increasing ammonia production, and stabilizing the hydrolyzer pressure.
By increasing the temperature of the urea supplement solution through heat exchange, the ammonia production of the hydrolyzer is enhanced, the pressure fluctuation problem is solved, the energy utilization rate is improved, and the need for an additional electric heating device is avoided.
Smart Images
Figure CN223832301U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the technical field of chemical process automation, and in particular to a urea hydrolysis device. Background Technology
[0002] The principle of SCR technology in coal-fired power plants is to use ammonia as a reducing agent to catalytically reduce nitrogen oxides at a temperature of 300-400℃, producing nitrogen and water that are non-toxic and harmless to the environment. Therefore, ammonia preparation has become an important step in SCR denitrification, and the ammonia preparation method has become a key research topic in this field. Urea is a stable, non-toxic solid granular material, and its transportation and storage do not require special requirements, making it an ideal method for ammonia production. Therefore, urea decomposition ammonia production technology is increasingly being used in flue gas denitrification projects. The main methods for ammonia production include the liquid ammonia method, the ammonia water method, and the urea method. Liquid ammonia is flammable and toxic, and prone to explosion; the ammonia water method requires the evaporation of large amounts of water, resulting in high energy consumption and the highest storage and transportation costs, and the metal ions in the ammonia water can shorten the catalyst life; urea, being a stable, non-toxic solid granular material, requires no special requirements for transportation and storage, making it an ideal method for ammonia production. Therefore, urea decomposition ammonia production technology is increasingly being used in flue gas denitrification projects.
[0003] During urea hydrolysis, urea solution needs to be continuously replenished to maintain the liquid level in the hydrolyzer. The temperature of the urea solution is usually 50℃, while the liquid temperature inside the hydrolyzer is around 150℃. When a large amount of urea solution is added to the hydrolyzer, the temperature inside the hydrolyzer drops, and the ammonia production inside the hydrolyzer decreases, which seriously affects the stable operation of the hydrolyzer and causes large fluctuations in the pressure at the outlet of the hydrolyzer, which seriously affects the operation and production of the boiler denitrification system. Utility Model Content
[0004] This invention provides a urea hydrolysis device to solve the problem of temperature drop in the hydrolyzer caused by the replenishment of urea solution, increase the ammonia production in the hydrolyzer, and better solve the problem of pressure fluctuation in the hydrolyzer.
[0005] According to one aspect of the present invention, a urea hydrolysis apparatus is provided, comprising:
[0006] The hydrolyzer is configured to provide a reaction site for the urea solution to be hydrolyzed and to output the hydrolysate through the first output terminal of the hydrolyzer.
[0007] A heat exchanger, wherein a first end of the heat exchanger is connected to a first output end of the hydrolyzer, a second end of the heat exchanger is connected to a first input end of the hydrolyzer, a third end of the heat exchanger is configured to input urea supplement solution, the second end of the heat exchanger and the third end of the heat exchanger are connected, and the heat exchanger is configured to exchange heat between the hydrolyzed effluent and the urea supplement solution.
[0008] Optionally, the heat exchanger includes a first pipeline and a second pipeline that are independently configured;
[0009] One end of the first pipeline is connected to the first output end of the hydrolyzer.
[0010] The first end of the second pipe is connected to the second end of the heat exchanger, and the second end of the second pipe is connected to the third end of the heat exchanger.
[0011] Optionally, the second conduit is wound around the first conduit.
[0012] Optionally, the urea hydrolysis device further includes: a hydrolysis effluent output pipeline, the first end of which is connected to the first output end of the hydrolyzer, and the first end of which is connected to the first end of the heat exchanger.
[0013] Optionally, the urea hydrolysis device further includes a first bypass pipeline, the first end of which is connected to the second end of the hydrolysis effluent output pipeline and is configured to output the hydrolysis effluent.
[0014] Optionally, the urea hydrolysis device further includes a first bypass valve;
[0015] The first bypass valve is installed on the first bypass pipeline.
[0016] Optionally, the urea hydrolysis device further includes a second bypass pipeline and a second bypass valve;
[0017] The first end of the second bypass pipeline is connected to the second end of the hydrolysate discharge pipeline, the second end of the second bypass pipeline is connected to the first end of the heat exchanger, and the second bypass valve is disposed on the second bypass pipeline.
[0018] Optionally, the urea hydrolysis device further includes: a replenishment liquid inlet pipeline and a urea solution replenishment valve;
[0019] The first end of the supplemental fluid inlet pipe is connected to the third end of the heat exchanger, and the second end of the supplemental fluid inlet pipe is configured to inlet the urea supplemental fluid.
[0020] The urea solution replenishment valve is located on the replenishment solution inlet pipeline.
[0021] Optionally, the urea hydrolysis device further includes an output pipeline and a temperature detection module, wherein the first end of the output pipeline is connected to the second end of the heat exchanger, and the second end of the output pipeline is connected to the first input end of the hydrolyzer;
[0022] The temperature detection module is located on the output pipeline.
[0023] Optionally, the urea hydrolysis device further includes a heating medium input pipeline;
[0024] The heating medium input pipeline is connected to the second input end of the hydrolyzer and is configured to input a heating medium into the hydrolyzer.
[0025] The urea hydrolysis device provided in this embodiment includes a heat exchanger. One heat exchanger is used to circulate urea supplement solution, and the other is used to circulate the hydrolysate output from the hydrolyzer. Compared to the urea supplement solution, the hydrolysate has a higher temperature. The urea supplement solution and the hydrolysate exchange heat in the heat exchanger, thereby increasing the temperature of the urea supplement solution, reducing the temperature drop after the urea supplement solution is input into the hydrolyzer, increasing the ammonia production of the hydrolyzer, and solving the pressure fluctuation problem of the hydrolyzer. By using the high-temperature hydrolysate generated by the hydrolyzer itself to heat the urea supplement solution, the temperature of the urea supplement solution does not need to be set up with an additional electric heating device, thus improving energy utilization efficiency.
[0026] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description
[0027] To more clearly illustrate the technical solutions in 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 only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0028] Figure 1 A schematic diagram of the structure of a urea hydrolysis device provided in an embodiment of this utility model;
[0029] Figure 2 This is a schematic diagram of another urea hydrolysis device provided in an embodiment of the present invention. Detailed Implementation
[0030] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.
[0032] Figure 1 This is a schematic diagram of a urea hydrolysis device provided in an embodiment of the present invention, with reference to... Figure 1 The device includes: a hydrolyzer 10, configured to provide a reaction site for the urea solution to be hydrolyzed, and to output the hydrolyzed effluent through the first output terminal U1 of the hydrolyzer 10;
[0033] The heat exchanger 11 has a first end A1 connected to the first output end U1 of the hydrolyzer 10, a second end A2 connected to the first input end I1 of the hydrolyzer 10, and a third end A3 configured to input urea supplement solution. The second end A2 and the third end A3 of the heat exchanger 11 are connected. The heat exchanger 11 is configured to exchange heat between the hydrolyzed effluent and the urea supplement solution.
[0034] The urea solution reacts in the hydrolyzer 10, almost completely decomposing into ammonia (NH3) and carbon dioxide (CO2). The urea solution after the reaction is called the hydrolysis discharge liquid or hydrophobic solution, which is discharged through the first output terminal U1 of the hydrolyzer 10. The urea replenishment liquid is the urea solution to be hydrolyzed that is input into the hydrolyzer 10 via the heat exchanger 11. The urea replenishment liquid with a first temperature is input into the heat exchanger 11, and the hydrolysis discharge liquid with a second temperature is output from the hydrolyzer 10 to the heat exchanger 11 via the third pipe 12. The second temperature is higher than the first temperature. The two liquids with different temperatures will exchange heat in the heat exchanger 11, so that after the heat exchange is completed, the temperature of the urea replenishment liquid rises from the first temperature to the third temperature. The urea replenishment liquid with the increased temperature is transferred to the hydrolyzer 10 via the output pipe 13. The third temperature is higher than the first temperature. The third pipe 12 is connected between the first output terminal U1 of the hydrolyzer 10 and the first terminal A1 of the heat exchanger 11, and the output pipe 13 is connected between the first input terminal I1 of the hydrolyzer 10 and the second terminal A2 of the heat exchanger 11. The third pipe 12 is used to transport the hydrolyzed discharge liquid, and the output pipe 13 is used to transport the urea replenishment liquid. In an optional embodiment, the first temperature can be 50°C, and the third temperature can be between 80°C and 90°C.
[0035] If the temperature inside the hydrolyzer 10 decreases due to the introduction of urea supplement solution, it will cause problems such as reduced ammonia production and pressure fluctuations within the hydrolyzer. In this embodiment, the temperature of the urea supplement solution input into the hydrolyzer is increased through heat exchange, reducing the disturbance to the liquid temperature inside the hydrolyzer during replenishment and increasing the ammonia production, thus effectively solving the pressure fluctuation problem of the hydrolyzer.
[0036] The urea hydrolysis device provided in this embodiment includes a heat exchanger. One heat exchanger is used to circulate urea supplement solution, and the other is used to circulate the hydrolysate output from the hydrolyzer. Compared to the urea supplement solution, the hydrolysate has a higher temperature. The urea supplement solution and the hydrolysate exchange heat in the heat exchanger, thereby increasing the temperature of the urea supplement solution, reducing the temperature drop after the urea supplement solution is input into the hydrolyzer, increasing the ammonia production of the hydrolyzer, and solving the pressure fluctuation problem of the hydrolyzer. By using the high-temperature hydrolysate generated by the hydrolyzer itself to heat the urea supplement solution, the temperature of the urea supplement solution does not need to be set up with an additional electric heating device, thus improving energy utilization efficiency.
[0037] Continue to refer to Figure 1 Optionally, the heat exchanger 11 includes a first pipe and a second pipe that are set separately.
[0038] One end of the first pipeline is connected to the first output terminal U1 of the hydrolyzer 10, specifically through... Figure 1 The third pipe 12 is connected to the first output terminal U1 of the hydrolyzer 10, and the other end is used to discharge the hydrolysate.
[0039] The first end of the second pipe is connected to the second end A2 of the heat exchanger 11, and the second end of the second pipe is connected to the third end A3 of the heat exchanger 11.
[0040] The heat exchanger 11 has a first pipe and a second pipe inside, and the first pipe and the second pipe are not connected to each other, independently transporting the liquid in their respective pipes. It should be further noted that... Figure 1 The first and second pipelines are not shown in the diagram. The first pipeline is used to transport the hydrolysate, and the second pipeline is connected between the second end A2 and the third end A3 of the heat exchanger 11 to transport the urea supplement solution. The first and second pipelines may not be in contact, but the distance between them is less than a distance threshold to ensure that the distance between the first and second pipelines is small, the heat exchange speed is fast, and the thermal energy utilization rate of the hydrolysate is high.
[0041] Optionally, the second pipe is wound around the first pipe to reduce the distance between the first and second pipes, thereby increasing the heating rate of the urea supplement solution and improving the thermal energy utilization rate of the hydrolysate.
[0042] Figure 2 This is a schematic diagram of another urea hydrolysis device provided in an embodiment of the present invention, with reference to... Figure 2 Based on the above embodiments, optionally, the urea hydrolysis device further includes: a hydrolysis discharge liquid output pipe 14, the first end of the hydrolysis discharge liquid output pipe 14 being connected to the first output end U1 of the hydrolyzer 10, and the second end of the hydrolysis discharge liquid output pipe 14 being connected to the first end A1 of the heat exchanger.
[0043] The hydrolysis effluent is discharged into the first pipeline of the heat exchanger 11 via the hydrolysis effluent output pipeline 14. In this embodiment, an output pipeline 13 is also included, through which urea supplement solution is sequentially input into the hydrolyzer 10 via the second pipeline and the output pipeline 13.
[0044] Continue to refer to Figure 2 Optionally, the urea hydrolysis device also includes a first bypass line 15, the first end of which is connected to the second end of the hydrolysis effluent output line 15 and is configured to output the hydrolysis effluent.
[0045] When the flow rate of the hydrolyzed effluent is large enough to exchange heat with the heat exchanger 11, the output path of the hydrolyzed effluent can be set to two. Part of the hydrolyzed effluent is directly output through the hydrolyzed effluent output pipe 14 and the first bypass pipe 15, while the other part of the hydrolyzed effluent is input into the heat exchanger 11 through the hydrolyzed effluent output pipe 14. After heat exchange, it becomes a low-temperature hydrolyzed effluent and is then output through the fourth pipe 16 connected to the fourth end A4 of the heat exchanger.
[0046] Continue to refer to Figure 2 Optionally, the urea hydrolysis device also includes a first bypass valve 17;
[0047] The first bypass valve 17 is installed on the first bypass pipeline 15.
[0048] The first bypass valve 17 can be a solenoid valve. When there is no need to input urea supplement solution into the hydrolyzer 10, the valve opening of the first bypass valve 17 can be 100%. When it is necessary to input urea supplement solution into the hydrolyzer 10, the opening of the first bypass valve 17 is reduced. The amount of reduction in opening is determined by the heat required by the urea supplement solution. The opening of the first bypass valve 17 is negatively correlated with the heat required by the urea supplement solution. The more heat required by the urea supplement solution, the greater the flow rate of the hydrolyzed discharge solution entering the heat exchanger 11, and the smaller the flow rate of the hydrolyzed discharge solution entering the first bypass pipeline 15. Therefore, the opening of the first bypass valve 17 is smaller.
[0049] Continue to refer to Figure 2 Optionally, the urea hydrolysis device also includes a second bypass pipeline 18 and a second bypass valve 19;
[0050] The first end of the second bypass pipe 18 is connected to the second end of the hydrolysis discharge liquid output pipe 14, the second end of the second bypass pipe 18 is connected to the first end A1 of the heat exchanger 11, and the second bypass valve 19 is installed on the second bypass pipe 18.
[0051] The second bypass valve 19 can be a solenoid valve. When there is no need to input urea supplement solution into the hydrolyzer 10, the second bypass valve 19 is closed, meaning that no hydrolysate is input into the heat exchanger 11, and all hydrolysate is output through the hydrolysate output pipeline 14 and the first bypass pipeline 15. When it is necessary to input urea supplement solution into the hydrolyzer 10, the second bypass valve 19 is opened, and the opening degree of the second bypass valve 19 is positively correlated with the heat required by the urea supplement solution. The higher the heat required by the urea supplement solution, the greater the flow rate of the hydrolysate entering the heat exchanger 11. Therefore, the opening degree of the second bypass valve 19 is larger.
[0052] The flow rate of the hydrolyzed liquid entering the heat exchanger 11 is controlled by the first bypass valve 17 and the second bypass valve 19 together. This avoids the situation where a single bypass valve fails, causing the flow rate of the hydrolyzed liquid entering the heat exchanger 11 to be uncontrollable, thus improving the operational stability of the urea hydrolysis unit.
[0053] Optionally, when the hydrolyzer 10 stops replenishing the liquid, the first bypass valve 17 is opened and the second bypass valve 19 is closed, so that the hydrolyzed effluent output from the hydrolyzer 10 no longer enters the heat exchanger 11.
[0054] Continue to refer to Figure 2Optionally, the urea hydrolysis device also includes: a replenishment liquid inlet pipe 20 and a urea solution replenishment valve 21;
[0055] The first end of the replenishment fluid inlet pipe 20 is connected to the third end of the heat exchanger 11, and the second end of the replenishment fluid inlet pipe 20 is configured to inlet urea replenishment fluid.
[0056] The urea solution replenishment valve 21 is installed on the replenishment liquid inlet pipeline 20.
[0057] The flow rate of urea solution replenishment valve 21 is directly proportional to the flow rate of urea replenishment solution input to heat exchanger 11. The more urea solution needed to be replenished in the hydrolyzer, the greater the flow rate of urea replenishment solution input to heat exchanger 11, and thus the larger the opening of urea solution replenishment valve 21. By controlling the opening of urea solution replenishment valve 21, the amount of urea replenishment solution entering reactor 10 is controlled.
[0058] Continue to refer to Figure 2 Optionally, the urea hydrolysis device also includes an output pipeline 13 and a temperature detection module 22. The first end of the output pipeline 13 is connected to the second end A2 of the heat exchanger 11, and the second end of the output pipeline 13 is connected to the first input end I1 of the hydrolyzer 10.
[0059] Temperature detection module 22 is installed on output pipeline 13.
[0060] The temperature detection module 22 can use any commercially available temperature sensor. It measures the temperature of the urea replenishment solution entering the hydrolyzer 10. Optionally, the urea unit also includes a control module connected to the temperature detection module 22, the first bypass valve 17, the second bypass valve 19, and the urea solution replenishment valve 21. The control module controls the opening degree of the first bypass valve 17 and the second bypass valve 19 based on the temperature of the urea replenishment solution entering the hydrolyzer 10 obtained by the temperature detection module 22. For example, the temperature of the urea replenishment solution entering the hydrolyzer 10 must reach 150°C. When the temperature output by the temperature detection module 22 is less than 150°C, the opening degree of the first bypass valve 17 can be reduced and / or the opening degree of the second bypass valve 19 can be increased. The urea solution replenishment valve 21's opening degree is increased or decreased under the control of the control module.
[0061] Continue to refer to Figure 2 Optionally, the urea hydrolysis device also includes a heating medium input pipeline 23;
[0062] The heating medium inlet pipe 23 is connected to the second inlet I2 of the hydrolyzer 10 and is configured to supply the heating medium to the hydrolyzer 10 to ensure that the temperature of the hydrolyzer 10 reaches the reaction temperature. The heating medium has a fourth temperature, which is between 130°C and 180°C. Specifically, the heating medium can be high-temperature steam.
[0063] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.
[0064] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A urea hydrolysis device, characterized in that, include: The hydrolyzer is configured to provide a reaction site for the urea solution to be hydrolyzed and to output the hydrolysate through the first output terminal of the hydrolyzer. A heat exchanger, wherein a first end of the heat exchanger is connected to a first output end of the hydrolyzer, a second end of the heat exchanger is connected to a first input end of the hydrolyzer, a third end of the heat exchanger is configured to input urea supplement solution, the second end of the heat exchanger and the third end of the heat exchanger are connected, and the heat exchanger is configured to exchange heat between the hydrolyzed effluent and the urea supplement solution.
2. The urea hydrolysis apparatus according to claim 1, characterized in that, The heat exchanger includes a first pipeline and a second pipeline that are set up independently. One end of the first pipeline is connected to the first output end of the hydrolyzer. The first end of the second pipe is connected to the second end of the heat exchanger, and the second end of the second pipe is connected to the third end of the heat exchanger.
3. The urea hydrolysis apparatus according to claim 2, characterized in that, The second pipe is wrapped around the first pipe.
4. The urea hydrolysis apparatus according to claim 1, characterized in that, It also includes: a hydrolysis effluent output pipeline, the first end of which is connected to the first output end of the hydrolyzer, and the first end of which is connected to the first end of the heat exchanger.
5. The urea hydrolysis apparatus according to claim 4, characterized in that, It also includes a first bypass pipeline, the first end of which is connected to the second end of the hydrolysate discharge pipeline and is configured to discharge the hydrolysate.
6. The urea hydrolysis apparatus according to claim 5, characterized in that, It also includes a first bypass valve; The first bypass valve is installed on the first bypass pipeline.
7. The urea hydrolysis apparatus according to claim 4, characterized in that, It also includes a second bypass pipeline and a second bypass valve; The first end of the second bypass pipeline is connected to the second end of the hydrolysate discharge pipeline, the second end of the second bypass pipeline is connected to the first end of the heat exchanger, and the second bypass valve is disposed on the second bypass pipeline.
8. The urea hydrolysis apparatus according to claim 1, characterized in that, Also includes: Supplemental fluid inlet line and urea solution replenishment valve; The first end of the supplemental fluid inlet pipe is connected to the third end of the heat exchanger, and the second end of the supplemental fluid inlet pipe is configured to inlet the urea supplemental fluid. The urea solution replenishment valve is located on the replenishment solution inlet pipeline.
9. The urea hydrolysis apparatus according to claim 1, characterized in that, It also includes an output pipeline and a temperature detection module. The first end of the output pipeline is connected to the second end of the heat exchanger, and the second end of the output pipeline is connected to the first input end of the hydrolyzer. The temperature detection module is located on the output pipeline.
10. The urea hydrolysis apparatus according to claim 1, characterized in that, It also includes the heating medium input pipeline; The heating medium input pipeline is connected to the second input end of the hydrolyzer and is configured to input a heating medium into the hydrolyzer.