Device for preparing ammonia through urea hydrolysis and ammonia water evaporation denitration
By designing an ammonia production device for urea hydrolysis and ammonia water evaporation and denitrification, and using technical means such as temperature and pressure adjustment and tube bundle heat exchanger, the corrosion and crystallization problems in urea hydrolysis ammonia production technology are solved, the stability and versatility of the ammonia production system are achieved, and the operational cost is reduced.
Patent Information
- Application Number
- CN202421827686.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-31
- Publication Date
- 2025-05-09
- Estimated Expiration
- 2034-07-31
AI Technical Summary
The existing urea hydrolysis ammonia production technology has the problem of pipeline blockage caused by carbamic corrosion equipment and urea crystallization, which limits its application in large power plants.
An ammonia production device for urea hydrolysis and ammonia evaporation and denitrification was designed. The temperature and pressure adjustment device were used to control the heat source temperature and pressure, and combined with a tube bundle heat exchanger and an ammonia evaporation, the parallel operation of two ammonia production methods of urea hydrolysis and ammonia evaporation were realized.
This device improves the stability and reliability of the ammonia production system, avoids the risk of failure caused by a single ammonia production method, extends the service life of the equipment, reduces operating costs and replacement frequency, and realizes the versatility of ammonia production function.
Smart Images
Figure CN222841841U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of flue gas denitration and ammonia production, in particular to a device for producing ammonia by denitration through urea hydrolysis and ammonia water evaporation. Background Art
[0002] At present, SCR denitrification ammonia production technology mainly uses liquid ammonia, ammonia water and urea as reducing agents. Liquid ammonia and ammonia water are generally produced by evaporators, and urea is generally produced by hydrolysis or pyrolysis.
[0003] The principle of producing ammonia using liquid ammonia or aqueous ammonia is as follows:
[0004] 4NH3+4NO+O2→4N2+6H2O.
[0005] The principle of denitrification reaction using urea hydrolysis to produce ammonia:
[0006] CO(NH2)2+H2O→NH2-COO-NH4→2NH2+CO2.
[0007] Although urea hydrolysis to produce ammonia has high safety, the carbamic acid easily produced during the hydrolysis process will cause strong corrosion to the equipment, increasing the maintenance cost and replacement frequency of the equipment. In addition, the instability of the hydrolysis temperature control may cause urea crystallization, which in turn causes the blockage of pipelines and equipment, seriously affecting the normal operation of the denitrification system. This limits the widespread application of urea hydrolysis to produce ammonia, especially in large power plants above 300MW. Therefore, the development of a urea hydrolysis and ammonia denitrification ammonia production common device that can avoid corrosion and crystallization problems while ensuring the stable operation of the ammonia production system has become an urgent problem to be solved. Utility Model Content
[0008] In order to solve the above problems, that is, to solve the problems raised by the above background technology, the utility model proposes a urea hydrolysis and ammonia evaporation denitrification ammonia production device, which includes a temperature and pressure regulating device for controlling the temperature and pressure of the heat source, one end of the temperature and pressure regulating device is provided with a heat source inlet, and the other end is provided with two branches; branch one: the other end of the ammonia evaporator regulating valve is connected to the ammonia evaporator through a pipeline, the ammonia evaporator is connected to the ammonia production pipeline through the ammonia production regulating valve, and the other end of the ammonia production pipeline is connected to an ammonia-air mixer; branch two: the other end of the hydrolyzer regulating valve group is connected to the tube bundle heat exchanger through a pipeline, the tube bundle heat exchanger is installed in the hydrolyzer, and a hydrolysis ammonia production port is opened at the top of the middle part of the hydrolyzer, the hydrolysis ammonia production port is connected to the hydrolysis ammonia production pipeline through the hydrolysis ammonia production regulating valve, and the other end of the hydrolysis ammonia production pipeline is connected to the ammonia production pipeline.
[0009] The utility model is further configured as follows: a hydrolysis dilution air regulating valve and an ammonia water dilution air regulating valve are respectively connected to one side of the top end of the ammonia-air mixer.
[0010] The utility model is further configured as follows: the heat source adopts 200-250° C. saturated steam.
[0011] The beneficial technical effect of the utility model is that the utility model can simultaneously realize two denitrification ammonia production methods, urea hydrolysis and ammonia water, to improve the overall stability and reliability of the ammonia production system. Through this dual ammonia production mechanism, the utility model can not only effectively avoid the risk of failure caused by a single ammonia production method, but also significantly extend the service life of the equipment, thereby significantly reducing operating costs and equipment replacement frequency. More importantly, the device realizes the versatility of the ammonia production function, allowing users to flexibly choose the ammonia production method according to actual needs, providing a more convenient and efficient solution for power plants and denitrification systems of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Figure 1 Shown is a schematic diagram of the structure of the utility model.
[0013] Figure numerals: 1. Hydrolyzer regulating valve group, 2. Temperature and pressure regulating device, 3. Ammonia evaporator regulating valve, 4. Hydrolyzer, 5. Hydrolysis and ammonia production regulating valve, 6. Ammonia evaporator, 7. Ammonia production and ammonia regulating valve, 8. Ammonia-air mixer, 9. Hydrolysis dilution air regulating valve, 10. Ammonia dilution air regulating valve, 11. Tube bundle heat exchanger, 12. Hydrolysis and ammonia production port, 13. Ammonia production pipeline, 14. Hydrolysis and ammonia production pipeline. DETAILED DESCRIPTION
[0014] Please refer to the attached Figure 1 Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.
[0015] The utility model proposes a device for producing ammonia by hydrolysis of urea and evaporation of ammonia water for denitrification, comprising a temperature and pressure regulating device 2 for controlling the temperature and pressure of a heat source, wherein a heat source inlet is arranged at one end of the temperature and pressure regulating device 2, and two branches are arranged at the other end;
[0016] Branch 1: the other end of the ammonia evaporator regulating valve 3 is connected to the ammonia evaporator 6 through a pipeline, the ammonia evaporator 6 is connected to the ammonia production pipeline 13 through the ammonia production regulating valve 7, and the other end of the ammonia production pipeline 13 is connected to the ammonia-air mixer 8;
[0017] Branch 2: The other end of the hydrolyzer regulating valve group 1 is connected to the tube bundle heat exchanger 11 through a pipeline. The tube bundle heat exchanger 11 is installed in the hydrolyzer 4. The hydrolyzer 4 is provided with a hydrolysis ammonia production port 12 at the top of the middle part. The hydrolysis ammonia production port 12 is connected to the hydrolysis ammonia production pipeline 14 through the hydrolysis ammonia production regulating valve 5. The other end of the hydrolysis ammonia production pipeline 14 is connected to the ammonia production pipeline 13. The hydrolyzer 4 with the tube bundle heat exchanger 11 is used, and the steam in the tube bundle heats the solution outside the tube bundle to produce ammonia, which meets the functional requirements that the hydrolyzer 4 can use urea hydrolysis and ammonia water to produce ammonia.
[0018] The top side of the ammonia-air mixer 8 is respectively connected with a hydrolysis dilution air regulating valve 9 and an ammonia water dilution air regulating valve 10. The hydrolysis dilution air regulating valve 9 and the ammonia water dilution air regulating valve 10 are respectively used to adjust the ammonia concentration requirements of urea hydrolysis to produce ammonia and ammonia water to produce ammonia.
[0019] The heat source of the hydrolyzer 4 and the ammonia evaporator 6 is saturated steam at 200-250°C. One path enters the tube bundle heat exchanger 11 through the hydrolyzer regulating valve group 1, and undergoes hydrolysis reaction with a urea solution with a concentration of about 50% outside the tube to produce ammonia. The hydrolyzer regulating valve group 1 is equipped with a steam regulating valve for urea hydrolysis and ammonia evaporation. The other path enters the ammonia evaporator 6 through the ammonia evaporator regulating valve 3 to evaporate and produce ammonia. Urea and ammonia can be used separately or together as backup raw materials for the hydrolyzer 4 to produce ammonia gas, so as to ensure a stable supply of ammonia gas.
[0020] When urea is hydrolyzed to produce ammonia, steam enters the hydrolyzer 4 tube bundle through the hydrolyzer regulating valve group 1 and reacts with the urea solution with a concentration of about 50% outside the tube to produce ammonia. The steam regulating valve in the hydrolyzer regulating valve group 1 regulates the steam flow.
[0021] When ammonia is produced by evaporating ammonia water, the steam enters the hydrolyzer 4 to produce ammonia through the ammonia water evaporator regulating valve 3, or enters the ammonia water evaporator 6 to evaporate and produce ammonia. The ammonia water steamer regulating valve 3 adjusts the steam flow rate and the temperature and pressure regulating device 2 adjusts the temperature. The produced ammonia enters the ammonia-air mixer 8 through the ammonia water ammonia production regulating valve 7, meeting the common requirements of urea hydrolysis in the hydrolyzer 4 and ammonia denitrification to produce ammonia.
[0022] Working principle:
[0023] When hydrolysis is used to produce ammonia, the concentration of ammonia produced is about 37%. The hydrolysis ammonia regulating valve 5 main pipe enters the furnace area, and the ammonia-air mixer 8 mixes with the hot air. The concentration of the mixed ammonia is adjusted to less than 5% by the hydrolysis dilution air regulating valve 9, and then the ammonia injection system is used to spray into the denitration reactor for denitration reaction;
[0024] When ammonia is produced by ammonia water, the ammonia concentration is about 20%. The ammonia concentration after mixing is adjusted to below 5% by the ammonia water dilution air regulating valve 10, and the ammonia gas enters the SCR denitration reactor through the ammonia injection system to complete the denitration reaction.
[0025] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
[0026] In the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.
[0027] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.
[0028] The term "comprise" or any other similar term is intended to cover a non-exclusive inclusion, such that a process, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, article, or apparatus / device.
[0029] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.
Claims
1. A device for producing ammonia by hydrolysis of urea and evaporation of ammonia water for denitrification, comprising a temperature and pressure regulating device (2) for controlling the temperature and pressure of a heat source, characterized in that: The temperature and pressure regulating device (2) is provided with a heat source inlet at one end and two branches at the other end; Branch 1: the other end of the ammonia evaporator regulating valve (3) is connected to the ammonia evaporator (6) through a pipeline, the ammonia evaporator (6) is connected to the ammonia production pipeline (13) through the ammonia production regulating valve (7), and the other end of the ammonia production pipeline (13) is connected to the ammonia-air mixer (8); Branch 2: The other end of the hydrolyzer regulating valve group (1) is connected to a tube bundle heat exchanger (11) through a pipeline. The tube bundle heat exchanger (11) is installed in the hydrolyzer (4). A hydrolysis ammonia production port (12) is opened at the top of the middle part of the hydrolyzer (4). The hydrolysis ammonia production port (12) is connected to a hydrolysis ammonia production pipeline (14) through a hydrolysis ammonia production regulating valve (5). The other end of the hydrolysis ammonia production pipeline (14) is connected to an ammonia water ammonia production pipeline (13).
2. The device for producing ammonia by urea hydrolysis and ammonia evaporation and denitration according to claim 1, characterized in that: One side of the top end of the ammonia-air mixer (8) is respectively connected to a hydrolysis dilution air regulating valve (9) and an ammonia water dilution air regulating valve (10).
3. The device for producing ammonia by urea hydrolysis and ammonia evaporation and denitration according to claim 1, characterized in that: The heat source is 200-250° C. saturated steam.