Green ammonia synthesis system capable of flexibly supplementing heat

Abstract

The invention discloses a green ammonia synthesis system with flexible heat compensation, which belongs to the technical field of ammonia synthesis and comprises a synthesis gas mixer, a first pipeline, a second pipeline, a third pipeline, a start-up electric furnace, an ammonia synthesis tower, a fourth pipeline, a boiler water heat exchange device, a heat exchanger, a fifth pipeline, a cooling device, an ammonia separator and a liquid nitrogen storage tank. The third pipeline is respectively communicated with the second pipeline and the top end of the ammonia synthesis tower; the starting electric furnace is arranged on the third pipeline; the fourth pipeline is respectively communicated with the bottom end of the ammonia synthesis tower and the heat exchanger; the boiler water heat exchange device is arranged on the fourth pipeline; the fifth pipeline is respectively communicated with the heat exchanger and the ammonia separator, the cooling device is arranged on the fifth pipeline, and the ammonia separator is communicated with a liquid nitrogen storage tank pipeline. The system can be flexibly heated to activate or maintain the activity of the catalyst when the system is influenced by the fluctuation of new energy electric power such as wind, light and the like and runs at low load.

Description

Technical Field

[0001] The invention belongs to the technical field of synthetic ammonia, and in particular relates to a green ammonia synthesis system with flexible heat supplementation. Background Art

[0002] Green ammonia synthesis mainly relies on green ammonia production technology, which is a process of using renewable energy to generate electricity, producing hydrogen through water electrolysis and nitrogen through air separation, and then synthesizing ammonia through the Haber process. This technology is called "green ammonia production" or "renewable ammonia", which aims to reduce carbon emissions generated in the traditional ammonia production process by using renewable energy throughout the process. Green ammonia synthesis units, affected by the volatility of new energy power such as wind and solar power, will have a long low-load operation range. The catalyst uses an iron-based catalyst, and the catalyst activity is low during low-load operation and start-up, which affects the production efficiency of synthetic ammonia. There are two operating conditions. One is that the temperature of the raw gas is low at the start-up, and a large amount of heat supplement is required in a short time; the other is a long time and a small amount of heat supplement under low-load operation (10%-35%). It is urgent for technicians in this field to propose a green ammonia synthesis system that can supplement heat to activate or maintain catalyst activity. Summary of the invention

[0003] In view of this, the present invention provides a green ammonia synthesis system with flexible heat supplementation to solve the above problems.

[0004] In order to achieve the above object, the present invention adopts the following technical solution:

[0005] A green ammonia synthesis system with flexible heat supplementation comprises: a synthesis gas mixer, a first pipeline, a second pipeline, a third pipeline, a start-up electric furnace, an ammonia synthesis tower, a fourth pipeline, a boiler water heat exchange device, a heat exchanger, a fifth pipeline, a cooling device, an ammonia separator and a liquid nitrogen storage tank, wherein the synthesis gas mixer is connected to the heat exchanger through the first pipeline, the heat exchanger is connected to the top of the ammonia synthesis tower through the second pipeline, one end of the third pipeline is connected to the second pipeline through a tee, and the other end is connected to the top of the ammonia synthesis tower, the start-up electric furnace is installed on the third pipeline, one end of the fourth pipeline is connected to the bottom of the ammonia synthesis tower, and the other end is connected to the heat exchanger, the boiler water heat exchange device is installed on the fourth pipeline, one end of the fifth pipeline is connected to the heat exchanger, and the other end is connected to the ammonia separator, the cooling device is installed on the fifth pipeline, and the ammonia separator is connected to the liquid nitrogen storage tank pipeline.

[0006] Furthermore, the boiler water heat exchange device includes a boiler water heat exchanger, a boiler water feed pipeline and a boiler water return pipeline, the boiler water heat exchanger is installed on the fourth pipeline, one end of the boiler water feed pipeline is connected to the boiler, and the other end is connected to the boiler water heat exchanger, and one end of the boiler water return pipeline is connected to the boiler water heat exchanger, and the other end is connected to the boiler.

[0007] Furthermore, the cooling device comprises an ammonia cooler, and the ammonia cooler is installed on the fifth pipeline.

[0008] Furthermore, the cooling device also includes a cold exchanger, a sixth pipeline and a seventh pipeline. The cold exchanger is installed on the fifth pipeline and is located before the ammonia cooler. One end of the sixth pipeline is connected to the top of the ammonia separator, and the other end is connected to the cold exchanger. One end of the seventh pipeline is connected to the cold exchanger, and the other end is connected to the synthesis gas mixer.

[0009] Furthermore, the cooling device also includes an ammonia synthesis water cooler, which is installed on the fifth pipeline and located before the cold exchanger.

[0010] The beneficial effects of the present invention are:

[0011] When the operating conditions of the present invention are normally operated, the start-up electric furnace does not need to provide heat to the ammonia synthesis tower; when the ammonia synthesis tower is operating at a low load, the start-up electric furnace is used to heat the synthetic ammonia mixed gas, and the synthetic ammonia mixed gas enters the ammonia synthesis tower for rapid heat supplement; the waste heat of boiler water can also be used to use a boiler water heat exchanger to exchange heat with the mixed gas after ammonia synthesis, and the heated ammonia synthesis mixer uses a heat exchanger to exchange heat with the synthetic ammonia mixed gas, and then enters the ammonia synthesis tower for heat supplement; the start-up electric furnace and the boiler water heat exchanger can also be started at the same time to heat the synthetic ammonia mixed gas, so as to realize flexible heat supplement to the ammonia synthesis tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0013] Figure 1 It is a schematic diagram of the structure of a green ammonia synthesis system with flexible heat supplementation;

[0014] Among them, in the figure:

[0015] 1-synthesis gas mixer, 2-first pipeline, 3-second pipeline, 4-third pipeline, 5-start-up electric furnace, 6-ammonia synthesis tower, 7-fourth pipeline, 8-heat exchanger, 9-fifth pipeline, 10-ammonia separator, 11-liquid nitrogen storage tank, 12-boiler water heat exchanger, 13-boiler water feed pipeline, 14-boiler water return pipeline, 15-ammonia cooler, 16-cold exchanger, 17-sixth pipeline, 18-seventh pipeline, 19-ammonia synthesis water cooler, 20-boiler. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Refer to the attached Figure 1 As shown, the present invention provides a green ammonia synthesis system with flexible heat supplement, comprising: a synthesis gas mixer 1, a first pipeline 2, a second pipeline 3, a third pipeline 4, a start-up electric furnace 5, an ammonia synthesis tower 6, a fourth pipeline 7, a boiler water heat exchange device, a heat exchanger 8, a fifth pipeline 9, a cooling device, an ammonia separator 10 and a liquid nitrogen storage tank 11, the synthesis gas mixer 1 is connected with the heat exchanger 8 through the first pipeline 2, the heat exchanger 8 is connected with the top of the ammonia synthesis tower 6 through the second pipeline 3, one end of the third pipeline 4 is connected with the second pipeline 3 through a tee, and the other end is connected with the top of the ammonia synthesis tower 6, the start-up electric furnace 5 is installed on the third pipeline 4, one end of the fourth pipeline 7 is connected with the bottom end of the ammonia synthesis tower 6, and the other end is connected with the heat exchanger 8, the boiler water heat exchange device is installed on the fourth pipeline 7, one end of the fifth pipeline 9 is connected with the heat exchanger 8, and the other end is connected with the ammonia separator 10, the cooling device is installed on the fifth pipeline 9, and the ammonia separator 10 is connected with the liquid nitrogen storage tank 11 pipeline.

[0018] The synthetic ammonia mixed gas in the synthesis gas mixer 1 enters the heat exchanger 8 through the first pipeline 2, and the ammonia mixed gas with heat output from the bottom of the ammonia synthesis tower 6 enters the heat exchanger 8 through the fourth pipeline 7. The synthetic ammonia mixed gas and the ammonia mixed gas exchange heat in the heat exchanger 8, and then the synthetic ammonia mixed gas enters the ammonia synthesis tower 6 through the second pipeline 3 to heat the catalyst and synthesize ammonia; if the synthetic ammonia mixed gas temperature is low during startup or low-load operation, and a large amount of heat supplement is required in a short time, the synthetic ammonia mixed gas can be entered into the startup electric furnace 5 through the third pipeline 4 for rapid heating, and then enter the ammonia synthesis tower 6 to heat the catalyst and synthesize ammonia. The ammonia synthesis tower 6 outputs the produced ammonia mixed gas through the fourth pipeline 7. When passing through the fourth pipeline 7, the ammonia mixed gas is heated by the preheating of the boiler water in the boiler water heat exchange device. The heated ammonia mixed gas heats the synthetic ammonia mixed gas in the heat exchanger 8, and the cycle is repeated.

[0019] Specifically, when the operating conditions are normal, the start-up electric furnace 5 does not need to provide heat to the ammonia synthesis tower 6; when the ammonia synthesis tower 6 is operating at a low load, the start-up electric furnace 5 is used to heat the synthetic ammonia mixed gas, and the synthetic ammonia mixed gas enters the ammonia synthesis tower 6 for rapid heat supplement; the waste heat of the boiler water can also be used to use the boiler water heat exchanger to exchange heat with the generated ammonia mixed gas, and the heated ammonia synthesis mixer uses the heat exchanger 8 to exchange heat with the synthetic ammonia mixed gas, and then enters the ammonia synthesis tower 6 for heat supplement; the start-up electric furnace 5 and the boiler water heat exchanger can also be started at the same time to heat the synthetic ammonia mixed gas, so as to realize flexible heat supplement to the ammonia synthesis tower 6.

[0020] In a preferred embodiment, the boiler water heat exchange device includes a boiler water heat exchanger 12, a boiler water feed pipeline 13 and a boiler water return pipeline 14, the boiler water heat exchanger 12 is installed on the fourth pipeline 7, one end of the boiler water feed pipeline 13 is connected to the boiler 20, and the other end is connected to the boiler water heat exchanger 12, and one end of the boiler water return pipeline 14 is connected to the boiler water heat exchanger 12, and the other end is connected to the boiler 20.

[0021] In a preferred embodiment, the cooling device includes an ammonia cooler 15, which is installed on the fifth pipeline 9. The ammonia cooler 15 cools the ammonia mixed gas for entering the ammonia separator 10 to separate liquid ammonia from hydrogen and nitrogen through gas-liquid separation.

[0022] In a preferred embodiment, the cooling device further comprises a cold exchanger 16, a sixth pipeline 17 and a seventh pipeline 18. The cold exchanger 16 is installed on the fifth pipeline 9 and is located before the ammonia cooler 15. One end of the sixth pipeline 17 is connected to the top of the ammonia separator 10 and the other end is connected to the cold exchanger 16. One end of the seventh pipeline 18 is connected to the cold exchanger 16 and the other end is connected to the synthesis gas mixer 1. The ammonia mixed gas comes out of the heat exchanger 8 and enters the fifth pipeline 9, and then enters the cold exchanger 16. At the same time, the ammonia separator 10 separates low-temperature nitrogen and hydrogen mixed gas. The low-temperature nitrogen and hydrogen mixed gas enters the cold exchanger 16 through the sixth pipeline 17. The low-temperature nitrogen and hydrogen mixed gas provides cooling for the ammonia mixed gas. The temperature of the ammonia mixed gas decreases and enters the ammonia cooler 15 for further cooling. The temperature of the nitrogen and hydrogen increases and enters the synthesis gas mixer 1 again through the seventh pipeline 18 to re-perform the synthetic ammonia cycle.

[0023] In a preferred embodiment, the cooling device further comprises an ammonia synthesis water cooler 19, which is installed on the fifth pipeline 9 and is located before the cold exchanger 16. The ammonia synthesis water cooler 19 pre-cools the ammonia mixed gas before entering the cold exchanger 16. Both the ammonia synthesis water cooler 19 and the cold exchanger 16 pre-cool the ammonia mixed gas gradually before entering the ammonia cold gas, thereby improving the cooling efficiency.

[0024] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0025] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A green ammonia synthesis system with flexible heat supplementation, characterized in that: include: A synthesis gas mixer (1), a first pipeline (2), a second pipeline (3), a third pipeline (4), a start-up electric furnace (5), an ammonia synthesis tower (6), a fourth pipeline (7), a boiler water heat exchange device, a heat exchanger (8), a fifth pipeline (9), a cooling device, an ammonia separator (10) and a liquid nitrogen storage tank (11), wherein the synthesis gas mixer (1) is connected to the heat exchanger (8) through the first pipeline (2), the heat exchanger (8) is connected to the top of the ammonia synthesis tower (6) through the second pipeline (3), and one end of the third pipeline (4) is connected to the second pipeline (6) through a tee. The first end of the pipeline (3) is connected to the ammonia synthesis tower (6), and the other end is connected to the top of the ammonia synthesis tower (6). The start-up electric furnace (5) is installed on the third pipeline (4). One end of the fourth pipeline (7) is connected to the bottom of the ammonia synthesis tower (6), and the other end is connected to the heat exchanger (8). The boiler water heat exchange device is installed on the fourth pipeline (7). One end of the fifth pipeline (9) is connected to the heat exchanger (8), and the other end is connected to the ammonia separator (10). The cooling device is installed on the fifth pipeline (9). The ammonia separator (10) is connected to the liquid nitrogen storage tank (11) pipeline.

2. A green ammonia synthesis system with flexible heat supplementation according to claim 1, characterized in that: The boiler water heat exchange device comprises a boiler water heat exchanger (12), a boiler water feed pipeline (13) and a boiler water return pipeline (14); the boiler water heat exchanger (12) is installed on the fourth pipeline (7); one end of the boiler water feed pipeline (13) is connected to the boiler (20) and the other end is connected to the boiler water heat exchanger (12); one end of the boiler water return pipeline (14) is connected to the boiler water heat exchanger (12) and the other end is connected to the boiler (20).

3. A green ammonia synthesis system with flexible heat supplementation according to claim 1, characterized in that: The cooling device comprises an ammonia cooler (15), and the ammonia cooler (15) is installed on the fifth pipeline (9).

4. A green ammonia synthesis system with flexible heat supplementation according to claim 3, characterized in that: The cooling device further comprises a cold exchanger (16), a sixth pipeline (17) and a seventh pipeline (18); the cold exchanger (16) is installed on the fifth pipeline (9) and is located before the ammonia cooler (15); one end of the sixth pipeline (17) is connected to the top end of the ammonia separator (10), and the other end is connected to the cold exchanger (16); one end of the seventh pipeline (18) is connected to the cold exchanger (16), and the other end is connected to the synthesis gas mixer (1).

5. A green ammonia synthesis system with flexible heat supplementation according to claim 4, characterized in that: The cooling device further comprises an ammonia synthesis water cooler (19), which is installed on the fifth pipeline (9) and located before the cold exchanger (16).

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