A new carbon ammonium production system for carbon emission reduction and resource utilization

Abstract

This application relates to the field of chemical production technology and discloses a novel ammonium bicarbonate production system for carbon emission reduction and resource utilization. The system includes a carbon capture unit, an ammonia recovery unit, a low-temperature ammonia carbonization reactor, a centrifuge, a fluidized bed dryer, and a tail gas treatment unit connected in sequence. In this novel ammonium bicarbonate production system for carbon emission reduction and resource utilization, industrial waste gas (CO₂ concentration 10%-20%) enters a cyclone gas-liquid contactor, where it comes into countercurrent contact with amine liquid under the action of vortex plates. The CO₂ absorption rate is >95%, thus ensuring the sustainability of the raw material. The ammonia synthesis tail gas (NH₃ concentration 5%-8%) is cooled to -15°C by a condenser. After liquid ammonia recovery, the remaining gas enters an ammonia stripping tower for deep concentration, with an NH₃ recovery rate ≥98%, thus enabling efficient resource utilization. Unreacted tail gas is treated by a catalytic oxidation device, where NH₃ is oxidized to N₂ and H₂O under the action of a palladium catalyst. The emission concentration is controlled in real time to <10ppm by an online monitoring instrument, thus achieving full environmental compliance.

Description

Technical Field

[0001] This application relates to the field of chemical production technology, specifically a novel ammonium bicarbonate production system for carbon emission reduction and resource utilization. Background Technology

[0002] Ammonium bicarbonate (NH4HCO3), commonly known as ammonium bicarbonate, is a white, orthorhombic or monoclinic crystalline solid. It is non-toxic and has an ammonia odor. It is soluble in water, forming an alkaline aqueous solution, but insoluble in ethanol. It is primarily used in agriculture as a high-nitrogen fertilizer. In my country, ammonium bicarbonate production is often integrated with melamine production facilities, utilizing melamine tail gas to provide the ammonia and some carbon dioxide needed for production. As a traditional nitrogen fertilizer, ammonium bicarbonate (ammonium carbonate) is typically produced in conjunction with ammonia synthesis systems, through a carbonization reaction that combines ammonia and carbon dioxide.

[0003] Traditional ammonium bicarbonate production processes suffer from the following technical drawbacks: unsustainable raw materials, relying on limestone calcination for CO2 production, resulting in 0.8 tons of CO2 emissions for every ton of ammonium bicarbonate produced, contradicting the goal of carbon neutrality; significant resource waste, with 5%-8% of NH3 in the ammonia synthesis tail gas being directly emitted, polluting the environment and increasing raw material costs; and NH3 concentrations in the tail gas exceeding 50 ppm and COD values ​​in wastewater exceeding 500 mg / L, failing to meet the latest environmental standards (such as GB 14554-2020), causing considerable inconvenience. Therefore, this paper proposes a novel ammonium bicarbonate production system that addresses carbon emission reduction and resource utilization. Utility Model Content

[0004] To address the shortcomings of existing technologies, this application provides a novel ammonium bicarbonate production system for carbon emission reduction and resource utilization, characterized by sustainable raw materials, efficient resource utilization, and full compliance with environmental protection standards.

[0005] To achieve the above objectives, this application provides the following technical solution: a novel ammonium bicarbonate production system for carbon emission reduction and resource utilization, comprising a carbon capture unit, an ammonia recovery unit, a low-temperature ammonia carbonization reactor, a waste heat-driven crystallization system, a centrifugal separator, a fluidized bed dryer, and a tail gas treatment unit connected in sequence. The carbon capture unit consists of a cyclone gas-liquid contactor and a molecular sieve adsorption tower. The waste gas inlet of the cyclone gas-liquid contactor is connected to an industrial flue. The ammonia recovery unit includes a condenser separator and an ammonia stripping tower. The inlet of the condenser separator is connected to a synthetic ammonia tail gas pipeline. The low-temperature ammonia carbonization reactor receives CO2 from the carbon capture unit and NH3 from the ammonia recovery unit for reaction. The waste heat-driven crystallization system includes a flash tank and a falling film crystallizer. The steam outlet of the flash tank is connected to the heating chamber of the falling film crystallizer via a heat pump. The centrifugal separator processes the crystallization slurry to obtain wet ammonium bicarbonate. The fluidized bed dryer dries the wet ammonium bicarbonate into a finished product. The tail gas treatment unit is equipped with a selective catalytic oxidation device and an online monitoring instrument to treat unreacted gases.

[0006] Through the above scheme, by setting up a carbon capture unit, an ammonia recovery unit, and a tail gas treatment unit, industrial waste gas (CO2 concentration 10%–20%) enters the cyclone gas-liquid contactor, where it comes into countercurrent contact with amine liquid under the action of the vortex plate, achieving a CO2 absorption rate of >95%, thus ensuring the sustainability of raw materials; the ammonia synthesis tail gas (NH3 concentration 5%–8%) is cooled to -15℃ by a condenser separator; after liquid ammonia recovery, the remaining gas enters the ammonia stripping tower for deep concentration, achieving an NH3 recovery rate of ≥98%, thus enabling efficient resource utilization; the unreacted tail gas is treated by a catalytic oxidation device, where NH3 is oxidized to N2 and H2O under the action of a palladium catalyst, and the emission concentration is controlled in real time to <10ppm by an online monitoring instrument, thus achieving full environmental compliance and improving the practicality of the device.

[0007] Furthermore, the swirling gas-liquid contactor is equipped with three layers of vortex plates, each layer of vortex plates has a blade inclination angle of 45°±5° and a layer spacing of 600-800mm.

[0008] The above scheme improves gas-liquid mass transfer efficiency by 40%, reduces pressure drop by 30%, and reduces energy consumption by 25%.

[0009] Furthermore, the molecular sieve adsorption tower is a dual-tower parallel structure, filled with 13X type molecular sieve, with a regeneration temperature of 200-220℃ and a regeneration gas of nitrogen.

[0010] Through the above scheme, the rich liquid is purified by molecular sieve adsorption tower, and the CO2 purity is ≥90%. The ammonia synthesis tail gas (NH3 concentration 5%~8%) is cooled to -15℃ by condenser separator.

[0011] Furthermore, the packing height of the ammonia stripping tower is 4-5m, and stainless steel ring packing is used. The steam pressure of the reboiler at the bottom of the tower is 0.3-0.5MPa.

[0012] With the above scheme, the remaining gas enters the ammonia stripping tower for deep concentration, and the NH3 recovery rate is ≥98% - the packing has strong corrosion resistance.

[0013] Furthermore, the CO2 distributor of the low-temperature ammonia carbonization reactor is a porous ceramic structure with pore size decreasing from 2 mm to 0.5 mm along the airflow direction and an open area ratio of 15%-25%.

[0014] The above scheme improves the uniformity of gas-liquid contact by 30% and the carbonization reaction conversion rate is ≥99.5%.

[0015] Furthermore, the heating chamber of the falling film crystallizer is equipped with serrated finned tubes, with a fin height of 8-10 mm and a fin spacing of 10-12 mm, and the material is titanium alloy.

[0016] The above method enhances the corrosion resistance of titanium alloys.

[0017] Furthermore, the catalytic oxidation device adopts a drawer-type catalyst module, which is filled with Pd / Al2O3 catalyst at a density of 0.75-0.85 g / cm³.

[0018] Through the above scheme, the unreacted tail gas is treated by a catalytic oxidation device, and NH3 is oxidized into N2 and H2O under the action of palladium catalyst.

[0019] Furthermore, the online monitoring instrument is a laser spectral analyzer with a detection accuracy of ≤1ppm, and the data is transmitted to the central control system in real time.

[0020] Using the above method, the emission concentration can be controlled in real time to <10ppm by an online monitoring instrument.

[0021] Compared with the prior art, the technical solution of this application has the following beneficial effects:

[0022] This novel ammonium bicarbonate production system, designed for carbon reduction and resource utilization, incorporates a carbon capture unit, an ammonia recovery unit, and a tail gas treatment unit. Industrial waste gas (CO2 concentration 10%–20%) enters a cyclone gas-liquid contactor, where it counter-currently contacts liquid amine under the action of vortex plates, achieving a CO2 absorption rate >95%, thus ensuring sustainable raw material utilization. Ammonia synthesis tail gas (NH3 concentration 5%–8%) is cooled to -15°C via a condenser. After liquid ammonia recovery, the remaining gas enters an ammonia stripping tower for deep concentration, achieving an NH3 recovery rate ≥98%, thus enabling efficient resource utilization. Unreacted tail gas is treated by a catalytic oxidation unit, where NH3 is oxidized to N2 and H2O under the action of a palladium catalyst. The emission concentration is controlled in real-time to <10 ppm via an online monitoring instrument, ensuring comprehensive environmental compliance and enhancing the practicality of the system. Attached Figure Description

[0023] Figure 1 This is a system architecture diagram of this application;

[0024] Figure 2 This is a system structure diagram of the carbon capture unit structure in this application;

[0025] Figure 3 This is a system structure diagram of the ammonia recovery unit process flow in this application;

[0026] Figure 4 This is a system structure diagram showing the energy flow direction of the waste heat driven crystallization system in this application;

[0027] Figure 5 This is a system structure diagram of the gas treatment path of the exhaust gas treatment unit in this application.

[0028] In the picture:

[0029] 1. Carbon capture unit; 101. Cyclone gas-liquid contactor; 102. Molecular sieve adsorption tower; 103. Waste gas inlet; 2. Ammonia recovery unit; 201. Condenser separator; 202. Ammonia stripping tower; 203. Gas inlet; 3. Low-temperature ammonia carbonization reactor; 4. Waste heat driven crystallization system; 401. Flash tank; 402. Falling film crystallizer; 403. Heat pump; 5. Centrifuge; 6. Fluidized bed dryer; 7. Tail gas treatment unit; 701. Catalytic oxidation device; 702. Online monitoring instrument. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0031] Please see Figure 1 , Figure 2 and Figure 3This embodiment presents a novel ammonium bicarbonate production system for carbon emission reduction and resource utilization, comprising a carbon capture unit 1, an ammonia recovery unit 2, a low-temperature ammonia carbonization reactor 3, a waste heat-driven crystallization system 4, a centrifuge 5, a fluidized bed dryer 6, and a tail gas treatment unit 7 connected in sequence. The carbon capture unit 1 consists of a cyclone gas-liquid contactor 101 and a molecular sieve adsorption tower 102. The exhaust gas inlet 103 of the cyclone gas-liquid contactor 101 is connected to an industrial flue. The ammonia recovery unit 2 includes a condenser separator 201 and an ammonia stripping tower 202. The inlet 203 of the condenser separator 201 is connected to a synthetic ammonia tail gas pipeline. The low-temperature ammonia carbonization reactor 3 receives CO2 from the carbon capture unit 1 and NH3 from the ammonia recovery unit 2 for reaction. The waste heat-driven crystallization system 4 includes a flash tank 401 and a falling film crystallizer 402. The steam outlet of the flash tank 401 is connected to the heating chamber of the falling film crystallizer 402 via a heat pump 403. The centrifuge 5 processes the crystallization slurry to obtain wet... Ammonium bicarbonate is dried into a finished product by a fluidized bed dryer 6. The tail gas treatment unit 7 is equipped with a selective catalytic oxidation device 701 and an online monitoring instrument 702 to treat unreacted gases. Through the setup of a carbon capture unit 1, an ammonia recovery unit 2, and a tail gas treatment unit 7, industrial waste gas (CO2 concentration 10%–20%) enters a cyclone gas-liquid contactor 101, where it comes into countercurrent contact with amine liquid under the action of a vortex plate, achieving a CO2 absorption rate >95%, thus ensuring the sustainability of the raw materials. The synthetic ammonia tail gas (NH3 concentration 5%–8%) is cooled to -15℃ by a condenser separator 201. After liquid ammonia recovery, the remaining gas enters an ammonia stripping tower 202 for deep concentration, achieving an NH3 recovery rate ≥98%, thus enabling efficient resource utilization. The unreacted tail gas is treated by the catalytic oxidation device 701, where NH3 is oxidized to N2 and H2O under the action of a palladium catalyst. The emission concentration is controlled in real-time to <10ppm by the online monitoring instrument 702, thus achieving full environmental compliance and improving the practicality of the device.

[0032] Please see Figure 1 , Figure 2 and Figure 3 The cyclone gas-liquid contactor 101 has three layers of vortex plates, each with a blade inclination angle of 45°±5° and a layer spacing of 600-800mm. The molecular sieve adsorption tower 102 is a dual-tower parallel structure, filled with 13X type molecular sieves, with a regeneration temperature of 200-220℃ and nitrogen as the regeneration gas. The packing height of the ammonia stripping tower 202 is 4-5m, using stainless steel ring packing. The steam pressure of the reboiler at the bottom of the tower is 0.3-0.5MPa. The gas-liquid mass transfer efficiency is increased by 40%, the pressure drop is reduced by 30%, and the energy consumption is reduced by 25%. The rich liquid is purified by the molecular sieve adsorption tower 102, with CO2 purity ≥90%. The ammonia synthesis tail gas (NH3 concentration 5%~8%) is cooled to -15℃ by the condenser separator 201, and the remaining gas enters the ammonia stripping tower 202 for deep concentration, with NH3 recovery rate ≥98%. The packing has strong corrosion resistance.

[0033] Please see Figure 1 , Figure 4 and Figure 5 The CO2 distributor of the low-temperature ammonia carbonization reactor 3 is a porous ceramic structure with pore size decreasing from 2 mm to 0.5 mm along the airflow direction and an open area ratio of 15%-25%. The heating chamber of the falling film crystallizer 402 is equipped with serrated finned tubes with a fin height of 8-10 mm and a fin spacing of 10-12 mm, made of titanium alloy. The catalytic oxidation device 701 adopts a drawer-type catalyst module, which is filled with Pd / Al2O3 catalyst with a filling density of 0.75-0.85 g / cm³. The online monitoring instrument 702 is a laser spectrometer with a detection accuracy of ≤1 ppm. The data is transmitted to the central control system in real time, improving the gas-liquid contact uniformity by 30% and the carbonization reaction conversion rate by ≥99.5%. The titanium alloy has enhanced corrosion resistance. Unreacted tail gas is treated by the catalytic oxidation device 701, where NH3 is oxidized to N2 and H2O under the action of palladium catalyst. The emission concentration is controlled in real time to <10 ppm by the online monitoring instrument 702.

[0034] In this embodiment, by setting up a carbon capture unit 1, an ammonia recovery unit 2, and a tail gas treatment unit 7, industrial waste gas (CO2 concentration 10%–20%) enters a cyclone gas-liquid contactor 101, where it comes into countercurrent contact with amine liquid under the action of a vortex plate, achieving a CO2 absorption rate of >95%, thus ensuring the sustainability of raw materials; the ammonia synthesis tail gas (NH3 concentration 5%–8%) is cooled to -15°C by a condenser separator 201; after liquid ammonia recovery, the remaining gas enters an ammonia stripping tower 202 for deep concentration, achieving an NH3 recovery rate of ≥98%, thus enabling efficient resource utilization; the unreacted tail gas is treated by a catalytic oxidation device 701, where NH3 is oxidized to N2 and H2O under the action of a palladium catalyst, and the emission concentration is controlled in real time to <10ppm by an online monitoring instrument 702, thus achieving full environmental compliance.

[0035] The working principle of the above embodiment is as follows: First, in the raw material pretreatment stage, industrial waste gas (CO2 concentration 10%~20%) enters the cyclone gas-liquid contactor 101, and under the action of the vortex plate, it comes into countercurrent contact with the amine liquid, with a CO2 absorption rate >95%; the rich liquid is purified by the molecular sieve adsorption tower 102, with a CO2 purity ≥90%, and the ammonia synthesis tail gas (NH3 concentration 5%~8%) is cooled to -15°C by the condenser separator 201; after liquid ammonia recovery, the remaining gas enters the ammonia stripping tower 202 for deep concentration, with an NH3 recovery rate ≥98%; then in the core reaction stage, CO2 and NH3 react under the conditions of 30°C and 0.3MPa, with the reaction equation: NH3 + CO2 + H2O → NH4HCO3; The gradient pore size distributor of the low-temperature ammonia carbonization reactor 3 ensures uniform gas-liquid contact and a conversion rate ≥99.5%; The reaction liquid enters the flash tank 401 for flash concentration, and the secondary steam is pressurized to 0.5MPa by the heat pump 403 and used as the heat source for the falling film crystallizer 402, with a crystallization thermal efficiency of 78%p; In the subsequent product and emission control stage, the crystallized slurry is separated into wet ammonium bicarbonate (containing 4% water) by a centrifuge, and then dried to a moisture content ≤0.5% at 105℃ by the fluidized bed dryer 6. The unreacted tail gas is treated by the catalytic oxidation device 701, and NH3 is oxidized to N2 and H2O under the action of palladium catalyst. The emission concentration is controlled in real time to <10ppm by the online monitoring instrument 702.

[0036] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

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

Claims

1. A novel carbon-ammonia production system oriented towards carbon emission reduction and resource utilization, comprising a carbon capture unit (1), an ammonia recovery unit (2), a low-temperature ammonia-carbonization reactor (3), a waste heat-driven crystallization system (4), a centrifugal separator (5), a fluidized bed dryer (6) and a tail gas treatment unit (7) connected in sequence, characterized in that: The carbon capture unit (1) consists of a cyclone gas-liquid contactor (101) and a molecular sieve adsorption tower (102). The exhaust gas inlet (103) of the cyclone gas-liquid contactor (101) is connected to an industrial flue. The ammonia recovery unit (2) includes a condenser separator (201) and an ammonia stripping tower (202). The air inlet (203) of the condenser separator (201) is connected to a synthetic ammonia tail gas pipeline. The low-temperature ammonia carbonization reactor (3) receives CO2 from the carbon capture unit (1) and NH3 from the ammonia recovery unit (2).

3. The reaction is carried out. The waste heat driven crystallization system (4) includes a flash tank (401) and a falling film crystallizer (402). The steam outlet of the flash tank (401) is connected to the heating chamber of the falling film crystallizer (402) through a heat pump (403). The centrifuge (5) processes the crystallization slurry to obtain wet ammonium bicarbonate. The fluidized bed dryer (6) dries the wet ammonium bicarbonate into a finished product. The tail gas treatment unit (7) is equipped with a selective catalytic oxidation device (701) and an online monitoring instrument (702) to treat unreacted gases.

2. The novel ammonium bicarbonate production system according to claim 1, characterized in that: The swirling gas-liquid contactor (101) is equipped with three layers of vortex plates. The blade inclination angle of each vortex plate is 45°±5° and the layer spacing is 600-800mm.

3. The novel ammonium bicarbonate production system according to claim 1, characterized in that: The molecular sieve adsorption tower (102) is a dual-tower parallel structure, filled with 13X type molecular sieve, with a regeneration temperature of 200-220℃ and a regeneration gas of nitrogen.

4. A novel ammonium bicarbonate production system for carbon emission reduction and resource utilization according to claim 1, characterized in that: The packing height of the ammonia stripping tower (202) is 4-5m, and stainless steel ring packing is used. The steam pressure of the reboiler at the bottom of the tower is 0.3-0.5MPa.

5. A novel ammonium bicarbonate production system for carbon emission reduction and resource utilization according to claim 1, characterized in that: The CO2 distributor of the low-temperature ammonia carbonization reactor (3) is a porous ceramic structure with pore size decreasing from 2 mm to 0.5 mm along the airflow direction and an opening rate of 15%-25%.

6. A novel ammonium bicarbonate production system for carbon emission reduction and resource utilization according to claim 1, characterized in that: The heating chamber of the falling film crystallizer (402) is arranged with serrated finned tubes, the fin height is 8-10mm, the fin spacing is 10-12mm, and the material is titanium alloy.

7. A novel ammonium bicarbonate production system for carbon emission reduction and resource utilization according to claim 1, characterized in that: The catalytic oxidation device (701) adopts a drawer-type catalyst module, which is filled with Pd / Al2O3 catalyst at a density of 0.75-0.85 g / cm³.

8. A novel ammonium bicarbonate production system for carbon emission reduction and resource utilization according to claim 1, characterized in that: The online monitoring instrument (702) is a laser spectral analyzer with a detection accuracy of ≤1ppm, and the data is transmitted to the central control system in real time.

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