Synthetic ammonia system based on utilization of methane and nitrogen

Abstract

The invention discloses a synthetic ammonia system based on methane and nitrogen utilization, comprising: a heating pipe, one side wall of which is provided with a gas inlet assembly for feeding; the plasma reactor is connected to the output end of the heating pipe through a pipeline, the gas output end of the plasma reactor is connected with an absorption tower, and a collecting unit for NH3 is arranged at the top end of the absorption tower; by arranging the heating pipe, the plasma reactor, the absorption tower, the rich liquid pump, the heat exchanger and the regeneration tower, raw materials adopted by the invention are rich CH4 and N2 in nature, NH3 preparation is carried out at normal temperature and normal pressure, a catalyst, an absorbent and a solvent are not used in quantity, the problems of air pollution and energy consumption are reduced, and the device is small in size, simple and convenient to operate and safe.

Description

Technical Field

[0001] The present invention particularly relates to a synthetic ammonia system based on the utilization of methane and nitrogen. Background Art

[0002] Ammonia is an inorganic compound with the chemical formula NH3. It is a colorless gas with a strong pungent odor. Ammonia can turn moist red litmus paper blue and produce a small amount of hydroxide ions in water. The conventional ammonia synthesis process is to obtain N2 and H2 under high temperature and high pressure with iron as a catalyst.

[0003] Patent CN2116177565A discloses a synthetic ammonia process, which includes the following steps: mixing hydrogen and nitrogen, compressing them, water-cooling them, and exchanging heat with the gas after ammonia separation to generate a hydrogen-nitrogen mixed gas; mixing the gas with liquid ammonia to form a low-temperature gas-liquid mixture, and obtaining liquid ammonia and mixed ammonia raw gas by flash evaporation separation at a high temperature; after the mixed ammonia gas is mixed with the synthesis gas, it is water-cooled to form an ammonia-rich gas-liquid mixture, and heat is exchanged with the low-temperature gas-liquid mixture, and finally enters an ammonia separator for separation; the gas after ammonia separation enters an ammonia synthesis tower for ammonia synthesis reaction; Patent CN2117585686A discloses a synthetic ammonia method: hydrogen and oxygen are produced by electrolyzing water, and nitrogen is produced by air separation of air; the hydrogen-nitrogen mixed gas is compressed and preheated to form a high-temperature and high-pressure raw gas, and finally enters an ammonia synthesis reactor to generate ammonia.

[0004] The existing production of ammonia is obtained by reacting nitrogen and hydrogen as raw materials under high temperature and high pressure catalysts. It has high energy consumption, strong dependence on raw hydrogen, and harsh reaction conditions. The use of large amounts of catalysts and absorbents during production will also cause air pollution. For this reason, we propose a synthetic ammonia system based on the utilization of methane and nitrogen. Summary of the invention

[0005] The object of the present invention is to provide a synthetic ammonia system based on the utilization of methane and nitrogen to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a synthetic ammonia system based on the utilization of methane and nitrogen, comprising:

[0007] A heating tube, wherein one side wall of the heating tube is provided with an air intake assembly for feeding;

[0008] A plasma reactor is connected to the output end of the heating tube through a pipeline, and the gas output end of the plasma reactor is connected to an absorption tower, and a collection unit for NH3 is arranged on the top of the absorption tower;

[0009] A rich liquid pump connected to the lower end of the absorption tower;

[0010] The heat exchanger is arranged at the output end of the rich liquid pump, and the output end of the heat exchanger is connected to the regeneration tower. The lower end of the regeneration tower is provided with a reflux component for conveying the regenerated lean liquid to the inner side of the absorption tower.

[0011] Preferably, the reflux component includes a heater, a lean liquid pump and a cooler, the heater is arranged at the lower end of the inner side of the regeneration tower to heat the lean liquid, the lean liquid pump is connected to the lower end of the regeneration tower, and the other end of the lean liquid pump is connected to the heat exchanger to transport the lean liquid, the cooler is connected to the upper end of a side wall of the heat exchanger, and the output end of the cooler is communicated with the absorption tower to reflux the regenerated lean liquid into the absorption tower.

[0012] Preferably, the heater is an electric heater.

[0013] Preferably, a combustion pipeline connected to an external flare is provided at the upper end of the regeneration tower.

[0014] Preferably, the lower end of the plasma reactor is connected to a fuel oil collection tank via a pipeline.

[0015] Preferably, the air intake assembly comprises an air intake pipe, a regulating valve and a gas flow meter, two air intake pipes are arranged side by side on one side wall of the heating tube, and the regulating valve and the gas flow meter are evenly distributed along the axial direction of the air intake pipe.

[0016] Preferably, a pressure gauge is installed on the air intake pipe to detect the internal pressure thereof.

[0017] Preferably, the plasma reactor is provided with an excitation power supply.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention is provided with a heating tube, a plasma reactor, an absorption tower, a rich liquid pump, a heat exchanger and a regeneration tower, thereby avoiding the traditional production of NH3 which needs to rely on hydrogen, has a complex process and high energy consumption. The raw materials used in the present invention are CH4 and N2 which are abundant in nature. The production of NH3 is carried out at normal temperature and pressure, and no catalyst, absorbent and solvent are used in large quantities, thereby reducing air pollution and energy consumption problems. The equipment is small in size, easy and safe to operate, with low investment and operating costs, and promotes CH4 conversion and reduces greenhouse gas emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the present invention.

[0021] In the figure: 101, air intake pipe; 1011, regulating valve; 1012, gas flow meter; 103, heating tube; 104, plasma reactor; 105, excitation power supply; 106, fuel oil collection tank; 107, absorption tower; 108, rich liquid pump; 109, heat exchanger; 110, regeneration tower; 111, heater; 112, lean liquid pump; 113, cooler. DETAILED DESCRIPTION

[0022] 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.

[0023] See also Figure 1 The present invention provides a technical solution: a synthetic ammonia system based on the utilization of methane and nitrogen, comprising:

[0024] A heating tube 103, one side wall of the heating tube 103 is provided with an air intake assembly for feeding;

[0025] It is convenient for the gas entering the heating tube 103 to be heated to a certain temperature when it flows through the device, and the heated CH4 and N2 are fully mixed here to ensure that the state of the gas meets the requirements of the synthesis reaction when entering the plasma reactor 104. The purpose of heating is to increase the reaction rate and reaction efficiency, especially when the synthesis is carried out in the plasma reactor 104;

[0026] The plasma reactor 104 is connected to the output end of the heating tube 103 through a pipeline, and the gas output end of the plasma reactor 104 is connected to the absorption tower 107. In the absorption tower 107, the gas is in contact with the solvent, and the absorption tower 107 exchanges these organic gases with the DMF lean solution component in the solution by convection. The purpose of this process is to remove unnecessary organic components from the gas flow. DMF is used as a solvent to absorb organic gases such as acetylene and ethylene in the gas flow. The lean solution is an unsaturated DMF solution, which enters the top of the absorption tower 107. The top of the absorption tower 107 is provided with a collection unit for NH3;

[0027] A rich liquid pump 108 is connected to the lower end of the absorption tower 107 to facilitate the transportation of the rich liquid;

[0028] The heat exchanger 109 is arranged at the output end of the rich liquid pump 108, and the output end of the heat exchanger 109 is connected to the regeneration tower 110. The lower end of the regeneration tower 110 is provided with a reflux component for conveying regenerated lean liquid to the inner side of the absorption tower 107. In the lean-rich liquid heat exchanger 109, the rich liquid will exchange heat with the lean liquid. Through this heat exchange, the temperature of the rich liquid will increase so as to enter the next stage of the regeneration process.

[0029] Preferably, the reflux component includes a heater 111, a lean liquid pump 112 and a cooler 113. The heater 111 is arranged at the lower end of the inner side of the regeneration tower 110 to heat the lean liquid. The lean liquid pump 112 is connected to the lower end of the regeneration tower 110, and the other end of the lean liquid pump 112 is connected to the heat exchanger 109 to transport the lean liquid. The cooler 113 is connected to the upper end of a side wall of the heat exchanger 109, and the output end of the cooler 113 is connected to the absorption tower 107 to reflux the regenerated lean liquid into the absorption tower 107, so as to facilitate the recycling of the lean liquid.

[0030] Preferably, the heater 111 is an electric heater, which is used to heat the DMF at the bottom of the regeneration tower 110 to promote the precipitation of organic components in the solvent and ensure that the solvent in the reaction process can be recycled.

[0031] Preferably, a combustion pipe connected to an external flare is provided at the upper end of the regeneration tower 110 to facilitate the combustion of organic components and reduce the pollution to the environment caused by direct discharge of organic components.

[0032] Preferably, the lower end of the plasma reactor 104 is connected to a fuel oil collection tank 106 via a pipeline to facilitate the collection of by-products for subsequent energy recovery.

[0033] Preferably, the air intake assembly includes an air intake pipe 101, a regulating valve 1011 and a gas flow meter 1012. Two air intake pipes 101 are arranged side by side on one side wall of the heating tube 103. The regulating valve 1011 and the gas flow meter 1012 are evenly distributed along the axial direction of the air intake pipe 101 to control the gas flow entering the heating tube 103, and the gas flow meter 1012 is used to monitor the actual flow of the gas. In this system, the raw gases are mainly CH4 and N2, and these two devices are used to ensure that the gas flow is stable and controllable.

[0034] Preferably, a pressure gauge for detecting the internal pressure of the air inlet pipe 101 is installed to facilitate the detection of the pressure of the pipe when transporting gas.

[0035] Preferably, an excitation power supply 105 is provided on the plasma reactor 104 .

[0036] The working principle and use process of the present invention are as follows: when in use, the regulating valve 1011 and the gas flow meter 1012 are used to control and read the gas flow, and the pressure gauge is used to read the gas pressure. The raw gas CH4 and N2 flow into the heating pipe 103 after passing through the regulating valve 1011 and the gas flow meter 1012 for heating, and enter the plasma reactor 104 for synthesis after being fully mixed. The fuel oil flows into the fuel oil collection tank 106 from the bottom of the plasma reactor 104, and the reacted gas enters from the lower part of the absorption tower 107 to form a convection with the DMF dimethylformamide lean liquid entering from the upper part of the absorption tower 107 to absorb acetylene and ethylene in the gas. The rich liquid after absorbing organic gases such as acetylene and ethylene is pressurized by the rich liquid pump 108 from the bottom of the absorption tower 107 and goes to the lean-rich liquid heat exchanger 109. After preliminary heating by the lean-rich liquid heat exchanger 109, it enters the regeneration tower 110 for analysis and regeneration. The DMF flowing to the bottom of the regeneration tower 110 is heated by the heater 111. The regenerated lean liquid is transferred from the bottom of the regeneration tower 110 by the lean liquid pump 112, initially cooled by the lean-rich liquid heat exchanger 109, and then enters the lean liquid cooler 113 for further cooling before entering from the upper part of the absorption tower 107, forming a cycle.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A synthetic ammonia system based on the utilization of methane and nitrogen, characterized in that: include: A heating tube (103), wherein a side wall of the heating tube (103) is provided with an air intake assembly for feeding; A plasma reactor (104) is connected to the output end of the heating tube (103) through a pipeline, and the gas output end of the plasma reactor (104) is connected to an absorption tower (107), and a collection unit for NH3 is arranged at the top of the absorption tower (107); A rich liquid pump (108) connected to the lower end of the absorption tower (107); The heat exchanger (109) is arranged at the output end of the rich liquid pump (108), and the output end of the heat exchanger (109) is connected to the regeneration tower (110). The lower end of the regeneration tower (110) is provided with a reflux component for conveying regenerated lean liquid to the inner side of the absorption tower (107).

2. A synthetic ammonia system based on the utilization of methane and nitrogen according to claim 1, characterized in that: The reflux component comprises a heater (111), a lean liquid pump (112) and a cooler (113); the heater (111) is arranged at the lower end of the inner side of the regeneration tower (110) to heat the lean liquid; the lean liquid pump (112) is connected to the lower end of the regeneration tower (110), and the other end of the lean liquid pump (112) is connected to the heat exchanger (109) to transport the lean liquid; the cooler (113) is connected to the upper end of a side wall of the heat exchanger (109), and the output end of the cooler (113) is connected to the absorption tower (107) to reflux the regenerated lean liquid into the absorption tower (107).

3. A synthetic ammonia system based on the utilization of methane and nitrogen according to claim 2, characterized in that: The heater (111) is an electric heater.

4. The synthetic ammonia system based on the utilization of methane and nitrogen according to claim 1, characterized in that: The upper end of the regeneration tower (110) is provided with a combustion pipeline connected to an external flare.

5. The synthetic ammonia system based on the utilization of methane and nitrogen according to claim 1, characterized in that: The lower end of the plasma reactor (104) is connected to a fuel oil collection tank (106) via a pipeline.

6. The synthetic ammonia system based on the utilization of methane and nitrogen according to claim 1, characterized in that: The air intake assembly comprises an air intake pipe (101), a regulating valve (1011) and a gas flow meter (1012); two air intake pipes (101) are arranged side by side on one side wall of the heating pipe (103); and the regulating valve (1011) and the gas flow meter (1012) are evenly distributed along the axial direction of the air intake pipe (101).

7. A synthetic ammonia system based on the utilization of methane and nitrogen according to claim 6, characterized in that: The air intake pipe (101) is provided with a pressure gauge for detecting the internal pressure thereof.

8. The synthetic ammonia system based on the utilization of methane and nitrogen according to claim 1, characterized in that: The plasma reactor (104) is provided with an excitation power supply (105).

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