Urea hydrolysis ammonia production system capable of recycling heat
By introducing components such as a urea hydrolysis reactor, an energy-saving heat exchanger, and a steam-water expansion tank into the urea hydrolysis ammonia production system, the heat generated by steam hydrophobicity is recovered, solving the problems of low heat utilization and visual pollution in the urea hydrolysis ammonia production system, and achieving reduced energy consumption and improved system stability.
Patent Information
- Application Number
- CN202423276436.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2026-01-06
- Estimated Expiration
- 2034-12-30
AI Technical Summary
In existing urea hydrolysis ammonia production systems, the utilization rate of steam hydrophobic heat is low, resulting in high operating costs and visual pollution problems.
Design a urea hydrolysis ammonia production system that recovers heat. Through components such as a urea hydrolysis reactor, an energy-saving heat exchanger, a steam-water expansion tank, and a steam pump, the system recovers the hydrophobic heat of steam, preheats the urea solution, and heats the urea solution in the urea dissolving tank and storage tank, thereby improving heat utilization and eliminating visual pollution.
It improves the utilization rate of steam heat, reduces energy consumption and operating costs, and eliminates the vibration of the condensate tank and the visual pollution of white smoke, ensuring stable system operation.
Smart Images
Figure CN223760995U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of air pollution control technology, specifically to a urea hydrolysis ammonia production system that recovers and utilizes heat. Background Technology
[0002] Currently, the most widely used denitrification technology both domestically and internationally is Selective Catalytic Reduction (SCR). Common reducing agents for SCR denitrification include liquid ammonia, ammonia water, and urea. Liquid ammonia and ammonia water are hazardous chemicals, posing significant safety hazards during transportation and unloading. Leaks could impact the safe operation of power plants, surrounding residents, and the ecological environment. Urea, on the other hand, is a non-toxic and harmless chemical product with excellent performance indicators and safe operation. Its chemical stability prevents sudden explosions, making it completely safe.
[0003] Currently, the main methods for producing ammonia from urea are urea pyrolysis and urea hydrolysis. Urea pyrolysis ammonia production equipment has a high operating cost, while urea hydrolysis is increasingly popular due to its low energy consumption, safety, and stability.
[0004] When using urea hydrolysis to produce ammonia for flue gas denitrification in power plants, steam is typically used as the heat source. The steam is not mixed with the urea solution and is returned through coils, with the condensate recovered to a condensate tank. The collected condensate is preferentially used to dissolve urea. Because the condensate produced during urea hydrolysis is large in volume, high in temperature, and carries steam, it easily causes vibration in the condensate tank, potentially leading to cracks in the welds. Only a small portion of the condensate can be used, resulting in low heat utilization and high operating costs. Furthermore, when the condensate encounters cold air at the top of the tank, it condenses into liquid water that floats in the air, forming "white smoke" and causing visual pollution.
[0005] Therefore, providing a urea hydrolysis ammonia production system with high heat utilization and low operating cost has become an urgent problem to be solved by those skilled in the art. Utility Model Content
[0006] In view of the shortcomings of existing technologies and in combination with the characteristics of urea hydrolysis ammonia production systems, this utility model proposes a urea hydrolysis ammonia production system that recovers heat and utilizes the hydrophobic heat of steam, thereby improving heat utilization efficiency, eliminating visual pollution, and reducing energy consumption and operating costs.
[0007] This utility model provides the following technical solution: a urea hydrolysis ammonia production system for heat recovery and utilization, including a urea hydrolysis reactor, an energy-saving heat exchanger, a steam-water expansion tank, a steam pump, a condensate tank, a urea dissolving tank, and a urea solution storage tank.
[0008] The urea hydrolysis reactor includes a heating steam inlet located at the top of a steam tube box, a heating pipe I located inside the urea hydrolysis reactor, and a steam condensate outlet located at the bottom of the steam tube box. The heating steam inlet is connected to the heating pipe I, and the steam condensate outlet is also connected to the heating pipe I.
[0009] The steam condensate outlet is connected to the heat source side inlet of the energy-saving heat exchanger via a pipeline, and the heat source side outlet of the energy-saving heat exchanger is connected to the inlet of the steam-water expansion tank via a pipeline; the cold source side inlet of the energy-saving heat exchanger is connected to the outlet of the urea solution delivery pump via a pipeline, and the cold source side outlet of the energy-saving heat exchanger is connected to the urea solution inlet of the urea hydrolysis reactor via a pipeline.
[0010] The outlet of the steam-water expansion container is connected to the inlet of the steam-driven pump via a pipeline, and the outlet of the steam-driven pump is connected to the inlet of the condensate tank via a pipeline;
[0011] The outlet of the condensate tank is connected to the inlet of the condensate pump, and the outlet of the condensate pump is connected to the inlet of the heating pipe II inside the urea dissolving tank, the water inlet of the urea dissolving tank, and the inlet of the heating pipe III inside the urea solution storage tank through pipelines.
[0012] The outlet of the heating pipe II inside the urea dissolving tank and the outlet of the heating pipe III inside the urea solution storage tank are respectively connected to the return water port of the condensate tank through pipelines.
[0013] Preferably, the heating tube I inside the urea hydrolysis reactor is a U-shaped tube; the heating tube II inside the urea dissolving tank and the heating tube III inside the urea solution storage tank are spiral coils; the U-shaped tube and the spiral coil are plain tubes or finned tubes.
[0014] Preferably, the energy-saving heat exchanger is a plate heat exchanger or a shell-and-tube heat exchanger; the plate heat exchanger is a frame type or a brazed type, and the shell-and-tube heat exchanger is a bare tube or a finned tube.
[0015] Preferably, the steam-water expansion container is arranged vertically or horizontally, and the steam-water expansion container is equipped with a flow guiding device and an anti-swirl device.
[0016] Preferably, the steam-driven pump is steam-powered and has a shut-off valve, a drain valve, and a check valve installed inside.
[0017] Preferably, the outlet of the urea dissolving tank is connected to the inlet of the urea dissolving pump via a pipeline, and the outlet of the urea dissolving pump is connected to the inlet of the urea solution storage tank via a pipeline.
[0018] Preferably, the outlet of the urea solution storage tank is connected to the inlet of the urea solution delivery pump via a pipeline, and the outlet of the urea solution delivery pump is connected to the cold source side inlet of the energy-saving heat exchanger via a pipeline.
[0019] Compared with the prior art, the beneficial effects of this utility model are:
[0020] (1) The urea hydrolysis ammonia production system for heat recovery and utilization described in this utility model uses the residual heat of steam from the urea hydrolysis reactor to preheat the urea solution before it enters the urea hydrolysis reactor, thereby increasing the temperature of the urea solution before it enters the hydrolyzer, improving the steam heat utilization rate, and reducing energy consumption.
[0021] (2) The urea hydrolysis ammonia production system for heat recovery and utilization described in this utility model has steam condensate cooled by an energy-saving heat exchanger and flashed by a steam-water expansion container, eliminating condensate box vibration and visual pollution of "white smoke", recovering steam condensate heat and ensuring stable system operation.
[0022] (3) The urea hydrolysis ammonia production system for heat recovery and utilization described in this utility model has steam condensate fed into the heating pipes of the urea dissolving tank and the urea solution storage tank to heat the urea solution in the urea dissolving tank and the urea solution storage tank, promote urea dissolution and prevent urea dissolution crystallization, reduce steam consumption and reduce operating costs. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in 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.
[0024] Figure 1 This is a schematic diagram of the structure of a urea hydrolysis ammonia production system for heat recovery and utilization described in this utility model.
[0025] In the diagram: 1-Urea hydrolysis reactor, 1.1-Heating steam inlet, 1.2-Heating tube I, 1.3-Steam condensate outlet, 1.4-Urea solution inlet, 2-Energy-saving heat exchanger, 3-Steam-water expansion tank, 4-Steam pump, 5-Condensate tank, 5.1-Condensate tank return port, 6-Condensate pump, 7-Urea dissolving tank, 7.1-Heating tube II, 7.2-Urea dissolving tank inlet, 8-Urea dissolving pump, 9-Urea solution storage tank, 9.1-Heating tube III, 10-Urea solution transfer pump. Detailed Implementation
[0026] To make the objectives, technical features, and advantages of this utility model clearer, specific embodiments of this utility model are now described with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without inventive effort are within the scope of protection of this utility model.
[0027] like Figure 1 As shown, this utility model provides a urea hydrolysis ammonia production system for heat recovery and utilization, including a urea hydrolysis reactor, an energy-saving heat exchanger, a steam-water expansion tank, a steam pump, a condensate tank, a urea dissolving tank, and a urea solution storage tank.
[0028] The urea hydrolysis reactor includes a heating steam inlet located at the top of the steam tube box, a heating tube I located inside the urea hydrolysis reactor, and a steam condensate outlet located at the bottom of the steam tube box. The heating steam is high-temperature superheated steam from the power plant that has been de-cooled and depressurized to 180°C and 1 MPa saturated steam. The steam is discharged from the steam condensate outlet after heat exchange through the heating tube I inside the urea hydrolysis reactor.
[0029] The steam condensate outlet is connected to the heat source inlet of the energy-saving heat exchanger via a pipeline, and the heat source outlet of the energy-saving heat exchanger is connected to the inlet of the steam-water expansion tank via a pipeline. The condensate temperature entering the steam-water expansion tank is 80–110°C. The cold source inlet of the energy-saving heat exchanger is connected to the outlet of the urea solution transfer pump via a pipeline, and the cold source outlet of the energy-saving heat exchanger is connected to the urea solution inlet of the urea hydrolysis reactor via a pipeline. Before preheating, the urea solution temperature is 30–50°C. After passing through the energy-saving heat exchanger, the urea solution temperature rises to 60–90°C before entering the urea hydrolysis reactor.
[0030] The outlet of the steam-water expansion container is connected to the inlet of the steam-driven pump via a pipeline, and the outlet of the steam-driven pump is connected to the inlet of the condensate tank via a pipeline; the outlet of the condensate tank is connected to the inlet of the condensate pump, and the outlet of the condensate pump is connected to the inlet of the internal heating pipe II of the urea dissolving tank, the water inlet of the urea dissolving tank, and the inlet of the internal heating pipe III of the urea solution storage tank via pipelines respectively; the outlet of the internal heating pipe II of the urea dissolving tank and the outlet of the internal heating pipe III of the urea solution storage tank are respectively connected to the return water inlet of the condensate tank via pipelines.
[0031] Preferably, the outlet of the urea dissolving tank is connected to the inlet of the urea dissolving pump via a pipeline, and the outlet of the urea dissolving pump is connected to the inlet of the urea solution storage tank via a pipeline. The outlet of the urea solution storage tank is connected to the inlet of the urea solution delivery pump via a pipeline, and the outlet of the urea solution delivery pump is connected to the cold source side inlet of the energy-saving heat exchanger via a pipeline.
[0032] Preferably, the heating tube I inside the urea hydrolysis reactor is a U-shaped tube; the heating tube II inside the urea dissolving tank and the heating tube III inside the urea solution storage tank are spiral coils; the U-shaped tubes and spiral coils are plain tubes or finned tubes. The energy-saving heat exchanger is a plate heat exchanger or a shell-and-tube heat exchanger; the plate heat exchanger is a frame type or a brazed type, and the shell-and-tube heat exchanger is a plain tube or a finned tube. The steam-water expansion tank is arranged vertically or horizontally, and the steam-water expansion tank is equipped with a flow guiding device and an anti-swirl device. The steam-driven pump is steam-powered, and the steam-driven pump is equipped with a shut-off valve, a drain valve, and a check valve.
[0033] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A heat-recovering urea hydrolysis ammonia production system, characterized by: It comprises a urea hydrolysis reactor (1), an energy-saving heat exchanger (2), a steam-water expander (3), a steam-driven pump (4), a water drain tank (5), a urea dissolving tank (7), and a urea solution storage tank (9). The urea hydrolysis reactor (1) comprises a heating steam inlet (1.1) arranged at the upper part of the steam header, a heating pipe I (1.2) arranged inside the urea hydrolysis reactor (1), and a steam drain outlet (1.3) arranged at the lower part of the steam header, wherein the heating steam inlet (1.1) is communicated with the heating pipe I (1.2), and the steam drain outlet (1.3) is communicated with the heating pipe I (1.2). The steam drain outlet (1.3) is communicated with the heat source side inlet of the energy-saving heat exchanger (2) through a pipeline, the heat source side outlet of the energy-saving heat exchanger (2) is communicated with the inlet of the steam-water expander (3) through a pipeline, the cold source side inlet of the energy-saving heat exchanger (2) is communicated with the outlet of the urea solution delivery pump (10) through a pipeline, and the cold source side outlet of the energy-saving heat exchanger (2) is communicated with the urea solution inlet (1.4) of the urea hydrolysis reactor (1) through a pipeline. The outlet of the steam-water expander (3) is communicated with the inlet of the steam-driven pump (4) through a pipeline, and the outlet of the steam-driven pump (4) is communicated with the inlet of the water drain tank (5) through a pipeline. The outlet of the water drain tank (5) is communicated with the inlet of the water drain pump (6), and the outlet of the water drain pump is communicated with the inlet of the internal heating pipe II (7.1) of the urea dissolving tank (7), the water inlet (7.2) of the urea dissolving tank, and the inlet of the internal heating pipe III (9.1) of the urea solution storage tank (9) through pipelines. The outlet of the internal heating pipe II (7.1) of the urea dissolving tank (7) and the outlet of the internal heating pipe III (9.1) of the urea solution storage tank (9) are respectively communicated with the backwater inlet (5.1) of the water drain tank through pipelines.
2. The heat-reclaiming urea hydrolysis ammonia production system of claim 1, wherein: The internal heating pipe I (1.2) of the urea hydrolysis reactor (1) is a U-shaped pipe, and the internal heating pipe II (7.1) of the urea dissolving tank (7) and the internal heating pipe III (9.1) of the urea solution storage tank (9) are spiral coils.
3. The heat recycling urea hydrolysis ammonia production system of claim 1, wherein: The energy-saving heat exchanger (2) is a plate heat exchanger or a shell-and-tube heat exchanger, the plate heat exchanger is a frame type or a brazing type, and the shell-and-tube heat exchanger is a light pipe or a finned tube.
4. The heat recycling urea hydrolysis ammonia production system of claim 1, wherein: The steam-water expander (3) is arranged in a vertical or horizontal manner, and a flow guide device and an anti-swirl device are arranged inside the steam-water expander (3).
5. The heat recycling urea hydrolysis ammonia production system of claim 1, wherein: The steam-driven pump (4) is steam-driven, and a cut-off valve, a drain valve, and a check valve are arranged inside the steam-driven pump (4).
6. The heat recycling urea hydrolysis ammonia production system of claim 1, wherein: The outlet of the urea dissolving tank (7) is communicated with the inlet of the urea dissolving pump (8), and the outlet of the urea dissolving pump (8) is communicated with the inlet of the urea solution storage tank (9).
7. The heat recycling urea hydrolysis ammonia production system of claim 1, wherein: The outlet of the urea solution storage tank (9) is communicated with the inlet of the urea solution delivery pump (10), and the outlet of the urea solution delivery pump (10) is communicated with the cold source side inlet of the energy-saving heat exchanger (2).