Ammonia synthesis catalyst reduction device
By introducing an exogenous gas system into the ammonia synthesis catalyst reduction device, the gas flow supply is optimized, and the problems of long catalyst temperature reduction time and waste of effective gas are solved, and the rapid reduction of catalyst and efficient utilization of effective gas are achieved.
Patent Information
- Application Number
- CN202421493404.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-27
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-06-27
AI Technical Summary
The heating and reduction time of existing ammonia synthesis catalysts is long, which hinders the factory start-up time and feed production progress. During the catalyst replacement period, effective gas cannot be effectively utilized, resulting in waste.
An ammonia synthesis catalyst reduction device was designed to introduce an external gas system, and the airflow supply of the ammonia synthesis tower was optimized through components such as compressors and control valves to achieve rapid reduction of the catalyst.
The device can significantly shorten the heating and reduction time of the catalyst after the new device is started or the catalyst is replaced, reduce the waste of effective gases, achieve rapid production, and carry out reduction operations in advance when external conditions are not met.
Smart Images
Figure CN222901042U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of reduction of ammonia synthesis catalysts, and specifically relates to a reduction device for ammonia synthesis catalysts. Background Art
[0002] Most of the ammonia synthesis catalysts at home and abroad adopt iron-based or iron-molybdenum double-based catalysts. This type of catalyst has the characteristics of long service life and stable use. The ammonia synthesis catalyst needs to be heated and reduced before it can have reaction activity. Generally, according to the catalyst manufacturer and original operation experience, the heating and reduction time of the ammonia synthesis catalyst generally takes 5 to 7 days. If you want to increase the activity of the catalyst and extend its service life, the reduction time may be postponed to 9 to 10 days, which seriously delays the start-up time of the factory and the progress of feeding production.
[0003] Many factories only replace the catalyst 1 to 2 times from the use of the ammonia synthesis catalyst to the expiration of the device service life. Generally, it will be replaced during the device overhaul period or new catalysts will be used in new projects. At this time, during the heating and reduction period of the catalyst, the effective gas cannot be reacted smoothly and can only be vented. During the reduction period, a large amount of effective gas will be vented and not effectively utilized, resulting in great waste. Content of the Utility Model
[0004] To solve the deficiencies of the existing technology, the utility model provides a reduction device for ammonia synthesis catalysts, including a compressor. The output end of the compressor supplies reducing gas to the ammonia synthesis tower through a supply pipe, and the input end of the compressor is communicated with one end of a three-way pipe. The other end of the three-way pipe is communicated with an external gas system through a sixth control valve, and the third end is communicated with a previous process system through a fifth control valve.
[0005] The external gas system includes: a high-pressure hose communicated with a reducing gas supply mechanism. The high-pressure hose is communicated with a second communication pipeline of a control pipeline through a seventh control valve. The second communication pipeline is communicated with a first supply pipeline and a second supply pipeline arranged in parallel. Along the gas flow direction on the first supply pipeline, a first control valve, a first flame arrester, and a second control valve are successively arranged. Along the gas flow direction on the second supply pipeline, a third control valve, a second flame arrester, and a fourth control valve are successively arranged. The ends of the first supply pipeline and the second supply pipeline are communicated with an external connection pipe through a first communication pipe. A pressure regulating valve is arranged on the external connection pipe, and the end of the external connection pipe is communicated with the sixth control valve.
[0006] Furthermore, at least two seventh control valves are communicated and arranged on the second communication pipeline, and each seventh control valve is communicated with a high-pressure hose.
[0007] Further, a pressure balance pipe is connected between the first supply pipeline and the second supply pipeline. One end of the pressure balance pipe is connected to the first supply pipeline between the first control valve and the first flame arrester, and the other end is connected to the second supply pipeline between the third control valve and the second flame arrester. An eighth control valve is provided on the pressure balance pipe.
[0008] Further, on the external source connection pipe, a safety valve is provided on the pipeline between the sixth control valve and the pressure regulating valve.
[0009] Further, an inlet pipe is provided at one end of the ammonia synthesis tower, and an outlet pipe is provided on the opposite side of the distal end of the inlet pipe. A heating sleeve assembly is fixedly sleeved on the outer wall of the ammonia synthesis tower. A hot gas pipe surrounding the outer wall of the ammonia synthesis tower is provided inside the heating sleeve assembly. The inlet end of the hot gas pipe is connected to the steam pipe, and the outlet end is connected to the cooling pipe. The steam pipe and the cooling pipe are connected to the steam system.
[0010] Further, an annular base is fixedly installed on the outer wall of the ammonia synthesis tower, and a plurality of rubber pads are provided at the bottom of the annular base.
[0011] The beneficial effects of the present utility model are as follows:
[0012] 1. By introducing an external source gas system, the present utility model changes the working process of the traditional reduction of ammonia synthesis catalysts, enabling the iron-cobalt double-system ammonia synthesis catalyst to be used without public works and raw material gas during the initial startup of a new device or during the first startup after the catalyst is replaced during a shutdown maintenance operation of the device, and can minimize the time for catalyst heating and reduction to achieve the effect of rapid production.
[0013] 2. The present utility model can not only ensure the thoroughness of catalyst reduction but also perform reduction operations in advance when external conditions are not met.
[0014] 3. By shortening the reduction period, the present utility model can not only achieve the effect of quickly providing benefits for the factory but also solve the problem of a large amount of waste of effective gas caused by the long-term venting of effective gas. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a three-dimensional structural schematic diagram of the present utility model;
[0016] Figure 2 is a three-dimensional structural schematic diagram of the external source gas system related structure of the present utility model;
[0017] Figure 3 is a three-dimensional structural schematic diagram of the ammonia synthesis tower and its related structures of the present utility model;
[0018] In the figure: 1, ammonia synthesis tower; 2, annular base; 3, inlet pipe; 4, outlet pipe; 5, heating jacket assembly; 6, steam pipe; 7, supply pipe; 8, compressor; 9, tee; 10, pressure regulating valve; 11, safety valve; 12, control pipeline; 1201, first supply pipeline; 12011, first control valve; 12012, second control valve; 1202, second supply pipeline; 12021, third control valve; 12022, fourth control valve; 1203, first connecting pipe; 1204, second connecting pipeline; 13, pressure balance pipe; 1301, eighth control valve; 14, high-pressure hose; 15, seventh control valve; 1601, first flame arrester; 1602, second flame arrester; 17, sixth control valve; 18, fifth control valve; 19, cooling pipe. Detailed implementation manners
[0019] The present utility model will be further described in detail below with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present utility model in a schematic manner, so they only show the components related to the present utility model.
[0020] Please note that the "upper", "lower", "left", "right", "top", "top end", "bottom end", "bottom" and other terms used in the present utility model to describe the positional relationship do not represent the absolute positional relationship between each module / component / assembly / part / element, but the relative positional relationship between each module / component / assembly / part / element.
[0021] Embodiment 1
[0022] An ammonia synthesis catalyst reduction device, as Figure 1 and Figure 2 shown, includes a compressor 8. The output end of the compressor 8 supplies reducing gas to the ammonia synthesis tower 1 through a supply pipe 7. The input end of the compressor 8 is communicated with one end of a tee 9. The other end of the tee is communicated with an external gas system through a sixth control valve 17, and the third end is communicated with a previous process system through a fifth control valve 18.
[0023] The external gas system includes: a high-pressure hose 14 connected to a reducing gas supply mechanism, and the high-pressure hose 14 is connected to a second communication pipeline 1204 of a control pipeline 12 through a seventh control valve 15. The second communication pipeline 1204 is connected to a first supply pipeline 1201 and a second supply pipeline 1202 arranged in parallel. Along the gas flow direction on the first supply pipeline 1201, a first control valve 12011, a first flame arrester 1601, and a second control valve 12012 are successively provided. Along the gas flow direction on the second supply pipeline 1202, a third control valve 12021, a second flame arrester 1602, and a fourth control valve 12022 are successively provided. The ends of the first supply pipeline 1201 and the second supply pipeline 1202 are connected to an external connection pipe through a first communication pipe 1203. A pressure regulating valve 10 is provided on the external connection pipe, and the end of the external connection pipe is connected to a sixth control valve 17.
[0024] The working principle of the device is as follows: When there is no utility engineering and raw material gas available during the initial startup of a new device, or during the first startup after the device undergoes a shutdown maintenance operation to replace the catalyst, the seventh control valve 15 and the sixth control valve 17 are opened, and the fifth control valve 18 is closed, so that external hydrogen can enter the ammonia synthesis tower 1 through the control pipeline 12. Then, at least one of the first supply pipeline 1201 or the second supply pipeline 1202 is selected. For example, the first supply pipeline 1201 is selected, and by adjusting the opening degrees of the first control valve 12011 and the second control valve 12012, the inlet pressure of the compressor 8 is maintained at 2.0 MPa. The setting of the pressure regulating valve 10 can further ensure that the passing air pressure is maintained at 2.0 MPa.
[0025] The compressor 8 presses the external hydrogen gas into the ammonia synthesis tower 1, so that the hydrogen content in the ammonia synthesis tower 1 reaches or exceeds 90%, thereby inhibiting the synthesis reaction of hydrogen and nitrogen, enabling more hydrogen to be used in the reduction reaction of the catalyst, and accelerating the reduction of the catalyst.
[0026] During the catalyst heating period, the system strictly increases the temperature according to the heating and reduction rate provided by the manufacturer. As the catalyst is heated and reduced, hydrogen is gradually consumed. To maintain the system pressure, the first control valve 12011 and the second control valve 12012 are gradually and slowly opened, the set value of the pressure regulating valve 10 is adjusted, and the inlet pressure of the compressor 8 is controlled to gradually increase from 2.0 MPa to 4.0 MPa with the reduction working condition.
[0027] When a single supply pipeline cannot meet the demand, the control valves of another supply pipeline can be slowly opened, such as the third control valve 12021 and the fourth control valve 12022 of the second supply pipeline 1202, to supply hydrogen to the ammonia synthesis tower 1. When the hot spot temperature of the catalyst rises to 350 °C, the reaction becomes intense and the hydrogen consumption surges sharply. If hydrogen cannot be supplied in time, the hot spot temperature of the catalyst should be maintained at 350 °C for isothermal operation. The iron oxide in the catalyst is gradually reduced to α-Fe, and reduced water continuously appears at the ammonia separation section. During the isothermal period of the system, the opening degrees of the first control valve 12011 and the second control valve 12012 are reduced, the third control valve 12021 and the fourth control valve 12022 are closed, the external gas system is continuously put into use, and a small amount of hydrogen gas is sent into the ammonia synthesis tower 1 for mild reduction. After the current process is started, the reduction time of the catalyst is reduced.
[0028] After the previous process is started, the ammonia synthesis tower 1 introduces hydrogen and nitrogen from the previous system. At this time, the pressure value of the pressure regulating valve 10 is set to 5.0 MPa to be consistent with the previous process, and the first control valve 12011 and the second control valve 12012 are slowly closed. At the same time, the fifth control valve 18 is opened to introduce the gas from the previous process into the system.
[0029] After a period of time, the seventh control valve 15 and the sixth control valve 17 are closed to cut the external gas system out of the system. The catalyst is reduced according to the water content at the outlet of the synthesis tower not higher than 3000 pmm. Because of the reduction with pure hydrogen from the external gas system in the early stage, the isothermal time of the catalyst is much less than the original design value. To reduce the water content of the catalyst leaving the tower, the circulation volume and fresh gas volume of ammonia synthesis are increased, and the low limit of the system pressure is no longer controlled. The system pressure is gradually increased to 8 MPa.
[0030] After the temperature rise and reduction of the first-stage and second-stage catalysts enter the final stage, the ammonia synthesis unit starts to increase the load to 30% to bring the heat of the upper stage into the lower stage to increase the heating rate. Continuously monitor the composition of the liquid ammonia product until the concentration of the liquid ammonia product is higher than 98%, and then it can be sent to the subsequent process for the synthesis of ammonia-consuming products such as urea / DMF, etc., to reduce the external sales volume of unqualified liquid ammonia. When the water vapor concentration at the outlet of the synthesis tower is lower than 300 ppm, the ammonia synthesis unit increases the load to 50% and operates at low load for 1 day. The temperature rise and reduction of the ammonia synthesis unit are completed.
[0031] Compared with the existing technology that completely relies on the previous process for catalyst reduction, the present utility model can obtain products at least 5 days in advance and reduce the large-scale venting of 5 days of effective gas. After comparison with the same device, there are no special differences in terms of the system operating pressure, ammonia net value, or hot spot temperature.
[0032] In addition, the present utility model does not rely on the previous process, so it can also be applied to the catalyst reduction when there is no other industrial support for a newly built off-site project or when the device is shut down for maintenance to replace the new catalyst.
[0033] According to an embodiment of the present utility model, as Figure 1 and Figure 2 shown, at least two seventh control valves 15 are communicatively provided on the second communication pipeline 1204, and each of the seventh control valves 15 is communicated with a high-pressure hose 14. This setting can provide a sufficient and stable gas source when a large amount of gas supply is required or the gas source is replaced.
[0034] Embodiment 2
[0035] Based on the ammonia synthesis catalyst reduction device of Embodiment 1, as Figure 1 and Figure 2 shown, a pressure balance pipe 13 is communicated between the first supply pipeline and the second supply pipeline. One end of the pressure balance pipe 13 is communicated with the first supply pipeline 1201 between the first control valve 12011 and the first flame arrester 1601, and the other end is communicated with the second supply pipeline 1202 between the third control valve 12021 and the second flame arrester 1602. An eighth control valve 1301 is provided on the pressure balance pipe 13.
[0036] The setting of the pressure balance pipe 13 can, when the first supply pipeline 1201 and the second supply pipeline 1202 are enabled simultaneously, balance the air pressure in the first supply pipeline 1201 and the second supply pipeline 1202 by opening the eighth control valve 1301, and reduce the damage to the device caused by the high-pressure section.
[0037] Embodiment 3
[0038] Based on the ammonia synthesis catalyst reduction device of Embodiment 1, as Figure 1 and Figure 2 shown, on the external source connection pipe, a safety valve 11 is provided on the pipeline between the sixth control valve 17 and the pressure regulating valve 10. When the inlet pressure of the compressor 8 exceeds 6.0 MPa, the safety valve trips to prevent the compressor from overpressurizing due to excessive pressure.
[0039] Embodiment 4
[0040] Based on the ammonia synthesis catalyst reduction device of Embodiment 1, as Figure 1 and Figure 3 shown, one end of the ammonia synthesis tower 1 is provided with an inlet pipe 3, and an outlet pipe 4 is provided on the side opposite to the distal end of the inlet pipe. The outer wall of the ammonia synthesis tower 1 is fixedly sleeved with a heating sleeve assembly 5, and a hot gas pipe surrounding the outer wall of the ammonia synthesis tower 1 is provided inside the heating sleeve assembly 5. The inlet end of the hot gas pipe is communicated with the steam pipe 6, and the outlet end is communicated with the cooling pipe 19. The steam pipe 6 and the cooling pipe 19 are connected to the steam system. This setting can provide an external heat source for the ammonia synthesis tower 1, which is helpful for the temperature rise control and heat preservation control of the ammonia synthesis tower 1.
[0041] Embodiment 5
[0042] The ammonia synthesis catalyst reduction device based on Embodiment 1 is as follows Figure 1 and Figure 3 As shown, an annular base 2 is fixedly installed on the outer wall of the ammonia synthesis tower 1, and a plurality of rubber pads are arranged at the bottom of the annular base 2. The annular base 2 can play a role in supporting and fixing, and the rubber pads can play a role in buffering, shock absorption and noise reduction.
[0043] Taking the above ideal embodiment based on the present utility model as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of the present utility model. The technical scope of the present utility model is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.
Claims
1. An ammonia synthesis catalyst reduction device, characterized in that: The invention comprises a compressor (8), wherein the output end of the compressor (8) supplies reducing gas to the ammonia synthesis tower (1) through a gas supply pipe (7), and the input end of the compressor (8) is connected to one end of a three-way pipe (9); the other end of the three-way pipe is connected to an external gas system through a sixth control valve (17), and the third end is connected to a previous process system through a fifth control valve (18); The external gas system comprises: a high-pressure hose (14) connected to the reducing gas supply mechanism, the high-pressure hose (14) being connected to a second connecting pipeline (1204) of the control pipeline (12) via a seventh control valve (15); the second connecting pipeline (1204) being connected to a first supply pipeline (1201) and a second supply pipeline (1202) arranged in parallel; a first control valve (12011), a first flame arrester (1602) and a second flame arrester (1603) being arranged in sequence on the first supply pipeline (1201) along the airflow direction; 1) a second control valve (12012); a third control valve (12021), a second flame arrester (1602), and a fourth control valve (12022) are sequentially arranged on the second supply pipeline (1202) along the airflow direction; the ends of the first supply pipeline (1201) and the second supply pipeline (1202) are connected to an external source connecting pipe through a first connecting pipe (1203); a pressure regulating valve (10) is arranged on the external source connecting pipe, and the end of the external source connecting pipe is connected to a sixth control valve (17).
2. The ammonia synthesis catalyst reduction device according to claim 1, characterized in that: At least two seventh control valves (15) are connected to the second connecting pipeline (1204), and each of the seventh control valves (15) is connected to a high-pressure hose (14).
3. The ammonia synthesis catalyst reduction device according to claim 1, characterized in that: A pressure balancing pipe (13) is connected between the first supply pipeline and the second supply pipeline; one end of the pressure balancing pipe (13) is connected to the first supply pipeline (1201) between the first control valve (12011) and the first flame arrester (1601), and the other end is connected to the second supply pipeline (1202) between the third control valve (12021) and the second flame arrester (1602); an eighth control valve (1301) is provided on the pressure balancing pipe (13).
4. The ammonia synthesis catalyst reduction device according to claim 1, characterized in that: A safety valve (11) is provided on the external source connecting pipe on the pipeline between the sixth control valve (17) and the pressure regulating valve (10).
5. The ammonia synthesis catalyst reduction device according to claim 1, characterized in that: An air inlet pipe (3) is provided at one end of the ammonia synthesis tower (1), and an air outlet pipe (4) is provided at the opposite side of the far end of the air inlet pipe; a heating sleeve assembly (5) is fixedly provided on the outer wall of the ammonia synthesis tower (1), and a hot air pipe surrounding the outer wall of the ammonia synthesis tower (1) is provided inside the heating sleeve assembly (5); the inlet end of the hot air pipe is connected to the steam pipe (6), and the outlet end is connected to the cooling pipe (19); the steam pipe (6) and the cooling pipe (19) are connected to the steam system.
6. The ammonia synthesis catalyst reduction device according to claim 1, characterized in that: An annular base (2) is fixedly mounted on the outer wall of the ammonia synthesis tower (1), and a plurality of rubber pads are arranged at the bottom of the annular base (2).