Production system and method for preparing industrial ammonia water by using ammonia-containing tail gas

Abstract

The invention discloses a production system and method for preparing industrial ammonia water by using ammonia-containing tail gas. The jet flow is formed by the nozzle of the parallel flow ejector, and the jet flow can generate local negative pressure, so that the ammonia-containing tail gas is introduced, the ammonia-containing tail gas and dilute ammonia water are mixed in the ejector, the two-phase fluid is in a high-speed turbulent flow state, the gas-liquid contact area is greatly increased, and efficient gas-liquid mixing and mass transfer are realized. The tail gas absorption tower adopts a sectional absorption principle, and dilute ammonia water is introduced into the middle part of the tower; clean demineralized water is introduced into the top of the tower, the ammonia content in discharged tail gas after absorption is small, the concentration of dilute ammonia water is high, and ammonia gas is fully recycled.

Description

Technical Field

[0001] The present invention relates to the technical field of synthetic ammonia, and particularly relates to a production system and method for preparing industrial ammonia water by using ammonia-containing tail gas. Background Art

[0002] In the production process of coal chemical industry, more and more attention has been paid to the tail gas emission, and the recovery and treatment of tail gas have become the key to the development of coal chemical industry devices. The ammonia water device undertakes the function of recovering ammonia-containing tail gas in the synthetic ammonia production process, converts the tail gas of the synthetic ammonia system into high-value-added industrial ammonia water, realizes carbon reduction and emission reduction, and turns waste into treasure. However, the current ammonia water device has low ammonia recovery efficiency, resulting in insufficient recovery and utilization of ammonia gas. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems in the related art to some extent.

[0004] To this end, an embodiment of the present invention provides a production system and method for preparing industrial ammonia water by using ammonia-containing tail gas.

[0005] In a first aspect, the present invention provides a production system for preparing industrial ammonia water by using ammonia-containing tail gas, including:

[0006] A co-current ejector, the top inlet end of the co-current ejector is connected to an ammonia-containing tail gas source, and a nozzle is arranged inside the co-current ejector;

[0007] A concentrated ammonia water plate cooler, the bottom outlet end of the co-current ejector is connected to the hot side inlet end of the concentrated ammonia water plate cooler;

[0008] A gas-liquid separator, the inlet end of the gas-liquid separator is connected to the hot side outlet end of the concentrated ammonia water plate cooler;

[0009] A tail gas absorption tower, the gas phase outlet end of the gas-liquid separator is connected to the bottom inlet end of the tail gas absorption tower, and the top of the tail gas absorption tower is connected to a demineralized water storage tank;

[0010] A dilute ammonia water plate cooler, the bottom outlet end of the tail gas absorption tower is connected to the hot side inlet end of the dilute ammonia water plate cooler, and the hot side outlet end of the dilute ammonia water plate cooler is respectively connected to the middle inlet end of the tail gas absorption tower and the nozzle inlet end through pipelines.

[0011] Further, the dilute ammonia water generates negative pressure after being ejected from the nozzle to introduce the ammonia-containing tail gas, and the ammonia-containing tail gas is mixed with the dilute ammonia water ejected from the nozzle in the co-current ejector.

[0012] Further, a cold medium is introduced into the cold side of the concentrated ammonia water plate cooler.

[0013] Further, a thermometer is provided at the hot side outlet end of the concentrated ammonia water plate cooler, and the temperature of the concentrated ammonia water flowing out from the hot side outlet end of the concentrated ammonia water plate cooler is below 40°C.

[0014] Further, an ammonia water concentration monitoring device is provided at the liquid phase outlet end of the gas-liquid separator.

[0015] Further, the cooled concentrated ammonia water is separated into a gas phase substance and a liquid phase substance after passing through the gas-liquid separator. The gas phase substance is the residual tail gas, and the liquid phase substance is industrial ammonia water.

[0016] Further, after passing the inspection, the liquid phase substance goes to the finished product tank.

[0017] Further, a tail gas monitoring device is provided at the top outlet end of the tail gas absorption tower.

[0018] Further, the residual tail gas is absorbed by demineralized water to produce dilute ammonia water. After being cooled by the dilute ammonia water plate cooler, the dilute ammonia water passes through the middle part of the tail gas absorption tower and the nozzle inlet end respectively.

[0019] In a second aspect, the present invention provides a production method for preparing industrial ammonia water using ammonia-containing tail gas, which uses the system proposed in the first aspect above and includes the following steps:

[0020] (1) In the co-current injector, the ammonia-containing tail gas is mixed with dilute ammonia water under negative pressure to produce concentrated ammonia water;

[0021] (2) After cooling, the concentrated ammonia water is separated into a gas phase substance and a liquid phase substance;

[0022] (3) The liquid phase substance is output as a finished product, and the gas phase substance is discharged after being absorbed by demineralized water to produce dilute ammonia water;

[0023] (4) After being cooled, part of the dilute ammonia water enters the tail gas absorption tower to absorb the gas phase substance, and part enters the co-current injector to absorb the ammonia-containing tail gas.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] The present invention uses the nozzle of the co-current injector to form a jet flow, and the jet flow will generate local negative pressure, thereby introducing the ammonia-containing tail gas. The ammonia-containing tail gas is mixed with dilute ammonia water in the injector, and the two-phase fluid is in a high-speed turbulent state, greatly increasing the gas-liquid contact surface, realizing efficient gas-liquid mixing and mass transfer.

[0026] The tail gas absorption tower of the present invention adopts the principle of segmented absorption. Dilute ammonia water is introduced into the middle of the tower; clean demineralized water is introduced into the top of the tower. The ammonia content in the discharged tail gas after absorption is low, and the concentration of dilute ammonia water is high, and ammonia gas is fully recovered. Description of the Drawings

[0027] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, wherein:

[0028] Figure 1 It is a schematic diagram of a production system for preparing industrial ammonia water by using ammonia-containing tail gas in the present invention.

[0029] Description of reference numerals:

[0030] 1. Co-current ejector; 2. Plate cooler for concentrated ammonia water; 3. Gas-liquid separator; 4. Tail gas absorption tower; 5. Plate cooler for dilute ammonia water; 6. Dilute ammonia water pump; 7. Concentrated ammonia water pump. Detailed implementation manners

[0031] Embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0032] The following describes a production system and method for preparing industrial ammonia water by using ammonia-containing tail gas proposed by the present invention in conjunction with the accompanying drawings.

[0033] As Figure 1 shown, the production system for preparing industrial ammonia water by using ammonia-containing tail gas of the present invention includes a co-current ejector 1, a plate cooler 2 for concentrated ammonia water, a gas-liquid separator 3, a tail gas absorption tower 4, and a plate cooler 5 for dilute ammonia water.

[0034] The top inlet end of the co-current ejector 1 is connected to an ammonia-containing tail gas source. The ammonia-containing tail gas enters the co-current ejector 1 from the top of the co-current ejector 1. Nozzles are arranged inside the co-current ejector 1. Dilute ammonia water enters the nozzles through the nozzle inlet end under the action of the dilute ammonia water pump 6. After the dilute ammonia water is ejected from the nozzles, it is dispersed and atomized. Using the co-current injection principle, the dilute ammonia water forms an injection flow after being ejected from the nozzles. The injection flow generates a local negative pressure, thereby introducing the ammonia-containing tail gas entering from the top of the co-current ejector 1. The ammonia-containing tail gas is mixed with the dilute ammonia water in the ejector. The ammonia-containing tail gas and the atomized dilute ammonia water are fully mixed to complete absorption, and the two-phase fluid is in a high-speed turbulent state, greatly increasing the gas-liquid contact surface and realizing efficient gas-liquid mixing and mass transfer.

[0035] The ammonia-containing tail gas is absorbed by dilute ammonia water to produce concentrated ammonia water and release heat, making the temperature of the concentrated ammonia water relatively high. When the temperature is relatively high, ammonia is volatile. Therefore, a concentrated ammonia water plate cooler 2 is provided downstream of the co-current injector 1. The bottom outlet end of the co-current injector 1 is connected to the hot side inlet end of the concentrated ammonia water plate cooler 2. After flowing out from the bottom of the co-current injector 1, the concentrated ammonia water enters the hot side of the concentrated ammonia water plate cooler 2. A cold medium is introduced into the cold side of the concentrated ammonia water plate cooler 2. The concentrated ammonia water on the hot side exchanges heat with the cold medium on the cold side in the concentrated ammonia water plate cooler 2. After heat exchange, the temperature of the concentrated ammonia water decreases. To ensure the concentration of the concentrated ammonia water and taking into account the volatility of ammonia, the temperature of the concentrated ammonia water is reduced to below 40°C, that is, the temperature of the concentrated ammonia water flowing out from the hot side outlet end of the concentrated ammonia water plate cooler 2 is below 40°C.

[0036] In some embodiments, a thermometer is provided at the hot side outlet end of the concentrated ammonia water plate cooler 2 to monitor the temperature of the cooled concentrated ammonia water in real time. It can be understood that when the temperature of the cooled concentrated ammonia water is too high, the flow rate of the cold side medium can be increased.

[0037] In some embodiments, the cold medium is circulating water.

[0038] In some embodiments, multiple concentrated ammonia water plate coolers 2 are arranged in parallel, so as to quickly cool down the concentrated ammonia water.

[0039] The gas-liquid separator 3 is provided downstream of the concentrated ammonia water plate cooler 2. The inlet end of the gas-liquid separator 3 is connected to the hot side outlet end of the concentrated ammonia water plate cooler 2. After the cooled concentrated ammonia water flows out from the hot side outlet end of the concentrated ammonia water plate cooler 2, it enters the gas-liquid separator 3 and is separated into gas-phase substances and liquid-phase substances by cyclone separation. The gas-phase substances are residual tail gas, and the liquid-phase substances are industrial ammonia water.

[0040] In some embodiments, an ammonia water concentration monitoring device is provided at the liquid-phase outlet end of the gas-liquid separator 3. The ammonia water concentration monitoring device is used to monitor the ammonia water concentration of the liquid-phase substances in real time. After the liquid-phase substances are monitored to be qualified, they are sent to the finished product tank under the action of the concentrated ammonia water pump 7. Being monitored to be qualified means that the liquid-phase substances are qualified industrial ammonia water, and its concentration is between 20% and 21%.

[0041] It can be understood that when the ammonia water concentration at the liquid-phase outlet end is too low, the flow rate of the ammonia-containing tail gas is increased; when the ammonia water concentration at the liquid-phase outlet end is too high, the flow rate of the ammonia-containing tail gas is decreased.

[0042] The tail gas absorption tower 4 is arranged downstream of the gas-liquid separator 3. The gas-phase outlet end of the gas-liquid separator 3 is connected to the bottom inlet end of the tail gas absorption tower 4. The gas-phase substance is the residual tail gas. After flowing out from the gas-phase outlet end of the gas-liquid separator 3, the gas-phase substance enters the tail gas absorption tower 4 through the bottom inlet end of the tail gas absorption tower 4. The top of the tail gas absorption tower 4 is connected to the demineralized water storage tank. The demineralized water storage tank is used to store demineralized water. The demineralized water enters the tail gas absorption tower 4 through the top inlet end of the tail gas absorption tower 4 and performs countercurrent absorption with the residual tail gas in a downward spraying manner, so as to fully absorb ammonia in the residual tail gas.

[0043] After the residual tail gas is absorbed by the demineralized water, dilute ammonia water is generated and heat is released. Under the action of the dilute ammonia water pump 6, the dilute ammonia water enters the dilute ammonia water plate cooler 5 to be cooled to below 30°C.

[0044] The hot-side outlet end of the dilute ammonia water plate cooler 5 is respectively connected to the middle inlet end and the nozzle inlet end of the tail gas absorption tower 4 through pipelines. After being cooled by the dilute ammonia water plate cooler 5, the dilute ammonia water is fed into the nozzle of the co-current injector 1 in one way and into the middle part of the bottom of the tail gas absorption tower 4 in the other way. The dilute ammonia water fed into the nozzle is used to absorb the ammonia-containing tail gas, and the dilute ammonia water fed into the tail gas absorption tower 4 is used to cooperate with the demineralized water to absorb the residual tail gas.

[0045] After the residual tail gas is absorbed by the demineralized water spray and the dilute ammonia water, the ammonia concentration is reduced to below 5 ppm and then discharged. In some embodiments, a tail gas monitoring device is arranged at the top outlet end of the tail gas absorption tower 4 to monitor the ammonia content of the tail gas at the top outlet of the tail gas absorption tower 4. When the ammonia content is below 5 ppm, it is discharged into the atmosphere.

[0046] In some embodiments, a thermometer is arranged at the hot-side outlet end of the dilute ammonia water plate cooler 5 to monitor the temperature of the cooled dilute ammonia water in real time. It can be understood that when the temperature of the cooled dilute ammonia water is too high, the flow rate of the cold-side medium can be increased.

[0047] In some embodiments, the cold medium is circulating water.

[0048] In some embodiments, a plurality of dilute ammonia water plate coolers 5 are arranged in parallel, so as to quickly cool the dilute ammonia water.

[0049] The tail gas absorption tower of the present invention adopts the principle of segmented absorption. Dilute ammonia water is introduced into the middle of the tower; clean demineralized water is introduced into the top of the tower. The ammonia content in the discharged tail gas after absorption is small, the concentration of the dilute ammonia water is high, and ammonia is fully recovered.

[0050] A production method for preparing industrial ammonia water by using ammonia-containing tail gas, using the system of the present invention, includes the following steps:

[0051] (1) In the co-current injector, the ammonia-containing tail gas is mixed with dilute ammonia water under negative pressure to generate concentrated ammonia water;

[0052] (2) The concentrated ammonia water is cooled and separated into a gaseous substance and a liquid substance;

[0053] (3) The liquid substance is output as a finished product, and the gaseous substance is discharged after being absorbed by demineralized water to produce dilute ammonia water;

[0054] (4) After being cooled, part of the dilute ammonia water enters the tail gas absorption tower 4 to absorb the gaseous substance, and part enters the co-current ejector 1 to absorb the ammonia-containing tail gas.

[0055] Among them, step (1) is realized by using the co-current ejector 1. A nozzle is arranged in the co-current ejector 1. After the dilute ammonia water is ejected from the nozzle, it is dispersed and atomized to generate a jet flow. The jet flow generates a local negative pressure, thereby introducing the ammonia-containing tail gas entering from the top of the co-current ejector 1. The ammonia-containing tail gas is mixed with the dilute ammonia water in the ejector, and the two phases of the ammonia-containing tail gas and the atomized dilute ammonia water are fully mixed to complete the absorption.

[0056] In step (2), the concentrated ammonia water is cooled and its temperature is reduced in the concentrated ammonia water plate cooler 2 and then enters the gas-liquid separator 3 for gas-liquid separation. After the concentrated ammonia water is separated by the gas-liquid separator, it is separated into a gaseous substance and a liquid substance.

[0057] In step (3), the liquid substance is industrial ammonia water, and the gaseous substance is residual tail gas. After the liquid substance is monitored to be qualified, it goes to the product tank, and the residual tail gas is absorbed countercurrently with demineralized water during the rising process.

[0058] In step (4), the residual tail gas is absorbed by demineralized water to produce dilute ammonia water and release heat. The dilute ammonia water enters the dilute ammonia water plate cooler 5 under the action of the dilute ammonia water pump 6 to cool down to below 30°C. After being cooled by the dilute ammonia water plate cooler 5, the dilute ammonia water is fed into the nozzle of the co-current ejector 1 in one way and into the middle of the bottom of the tail gas absorption tower 4 in the other way. The dilute ammonia water fed into the nozzle is used to absorb the ammonia-containing tail gas, and the dilute ammonia water fed into the tail gas absorption tower 4 is used to co-absorb the residual tail gas with demineralized water. After the residual tail gas is absorbed, the ammonia concentration is reduced to below 5 ppm and then discharged.

[0059] The following describes the present invention in conjunction with a specific embodiment.

[0060] 3500 NM at 0.2 MPa 3 / h of ammonia-containing tail gas enters the top of the co-current ejector 1 after being depressurized to atmospheric pressure through a regulating valve. The nozzle blows and atomizes 8.9 m 3 / h of dilute ammonia water from the dilute ammonia water pump 6. The gas-liquid two phases are fully mixed inside the co-current ejector 1. The 60°C solution after mixing passes through the concentrated ammonia water plate cooler 2, and using 25°C circulating water as the refrigerant, the 60°C solution is cooled to 28°C. The cooled solution is separated in the gas-liquid separator 3. The liquid phase in the separator is industrial ammonia water with a concentration of 20%. The industrial ammonia water is transported to the storage tank by the concentrated ammonia water pump, and the flow rate is 11 m 3 / h, the separator liquid level is controlled at 46%.

[0061] The residual tail gas separated from the top of the gas-liquid separator 3 enters the bottom of the tail gas absorption tower 4. 9.1 m 3 / h of desalted water is sprayed down from the top of the absorption tower and countercurrently absorbs with the residual tail gas. After the ammonia concentration in the residual gas at the top of the tower drops below 5 ppm, it is discharged into the air at high altitude. The dilute ammonia water at the bottom of the absorption tower passes through the dilute ammonia water pump 6 and is cooled to 26 °C by the dilute ammonia water plate cooler 5. One way is 8.9 m 3 / h of dilute ammonia water is transported to the co-current injector 1, and the other way is to transport 0.2 m 3 / h of dilute ammonia water to the middle of the tail gas absorption tower 4 for concentrating the dilute ammonia water in the tail gas absorption tower 4. The liquid level of the absorption tower is controlled at 55%.

[0062] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms may be directed to different embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0063] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, "a plurality" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0064] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A production system for preparing industrial ammonia water using ammonia-containing tail gas, characterized in that: include: A parallel flow ejector, wherein the top inlet end of the parallel flow ejector is connected to an ammonia-containing tail gas source, and a nozzle is arranged inside the parallel flow ejector; A concentrated ammonia water plate cooler, wherein the bottom outlet of the parallel flow ejector is connected to the hot side inlet of the concentrated ammonia water plate cooler; A gas-liquid separator, wherein the inlet end of the gas-liquid separator is connected to the hot side outlet end of the concentrated ammonia water plate cooler; A tail gas absorption tower, wherein the gas phase outlet end of the gas-liquid separator is connected to the bottom inlet end of the tail gas absorption tower, and the top of the tail gas absorption tower is connected to a desalted water storage tank; A dilute ammonia plate cooler, wherein the bottom outlet of the tail gas absorption tower is connected to the hot side inlet of the dilute ammonia plate cooler, and the hot side outlet of the dilute ammonia plate cooler is respectively connected to the middle inlet of the tail gas absorption tower and the nozzle inlet through pipelines.

2. The system according to claim 1, characterized in that After the dilute ammonia water is sprayed out through the nozzle, negative pressure is generated to introduce ammonia-containing tail gas, and the ammonia-containing tail gas and the dilute ammonia water sprayed out from the nozzle are mixed in the co-current ejector.

3. The system according to claim 1, characterized in that A cold medium is introduced into the cold side of the concentrated ammonia water plate cooler.

4. The system according to claim 1, characterized in that A thermometer is arranged at the hot side outlet end of the concentrated ammonia water plate type cooler, and the temperature of the concentrated ammonia water flowing out from the hot side outlet end of the concentrated ammonia water plate type cooler is below 40°C.

5. The system according to claim 1, wherein: An ammonia concentration monitoring device is arranged at the liquid phase outlet of the gas-liquid separator.

6. The system according to claim 1, wherein: The cooled concentrated ammonia water is separated into gas phase substance and liquid phase substance after passing through the gas-liquid separator, wherein the gas phase substance is residual tail gas and the liquid phase substance is industrial ammonia water.

7. The system according to claim 6, characterized in that The liquid phase material goes to the finished product tank after being monitored and qualified.

8. The system according to claim 6, characterized in that A tail gas monitoring device is arranged at the top outlet end of the tail gas absorption tower.

9. The system according to claim 6, characterized in that The desalted water absorbs the residual tail gas to generate dilute ammonia water, and the dilute ammonia water is cooled by the dilute ammonia water plate cooler and passes through the middle of the tail gas absorption tower and the nozzle inlet end respectively.

10. A method for preparing industrial ammonia water using ammonia-containing tail gas, characterized in that: Using the system described in any one of claims 1 to 9, comprising the following steps: (1) In the co-current ejector, the ammonia tail gas is mixed with dilute ammonia water under negative pressure to produce concentrated ammonia water; (2) the concentrated ammonia solution is cooled and separated into gas phase substance and liquid phase substance; (3) The liquid phase substance is output as a finished product, and the gas phase substance is discharged after being absorbed by desalted water to produce dilute ammonia water; (4) After being cooled, part of the diluted ammonia water enters the tail gas absorption tower to absorb the gas phase substances, and part of it enters the co-current ejector to absorb the ammonia-containing tail gas.

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