A pressure-regulated ammonium bicarbonate ammonia production reactor control system and method

Abstract

The invention discloses a pressure-regulated control system and method for an ammonium bicarbonate ammonia production reactor, comprising a product gas outlet valve, a product gas detector and a control system. The product gas outlet of the ammonium bicarbonate ammonia production reactor is connected to the inlet of the product gas detector via the product gas outlet valve, a reactor pressure gauge is provided on the top of the sodium bicarbonate ammonia production reactor, a reactor pressure regulating valve is provided at the pressure regulating port on the top of the sodium bicarbonate ammonia production reactor, and the control system is connected to the reactor pressure regulating valve, the reactor pressure gauge, the product gas detector and the product gas outlet valve. The system and method can improve the followability of the sodium bicarbonate ammonia production reactor to the unit load.

Description

Technical Field

[0001] The invention belongs to the technical field of ammonia preparation, and relates to a pressure-regulated ammonium bicarbonate ammonia production reactor control system and method. Background Art

[0002] Common ammonia production reagents used in denitrification systems include liquid ammonia, aqueous ammonia, and urea. Both the liquid ammonia and aqueous ammonia methods present significant safety risks, including certain risks during transportation and storage. The urea method offers high safety, but also carries high raw material, system investment, and operating costs. Furthermore, decomposition byproducts can cause corrosion in equipment and piping, as well as clogging and poisoning of catalysts.

[0003] Ammonium bicarbonate is my country's second-largest nitrogen fertilizer after urea, presenting no safety issues in storage and transportation. Compared to urea, ammonium bicarbonate has a lower decomposition temperature (<100°C) and is more affordable, making it a highly efficient and economical new denitrification reducing agent.

[0004] Technical solutions using ammonium bicarbonate as a reagent for SCR ammonia production can be broadly categorized into two types: solid pyrolysis (CN200910086856) and solution wet ammonia production (CN201010194802, CN202111307077). The solution wet ammonia production process offers uniform feed and stable ammonia production, but effective control methods and systems for ammonium bicarbonate solution decomposition are currently lacking.

[0005] In existing wet ammonia production systems, heat-based control methods are often used (CN201510425496, CN201510772045), and the reactor pressure is maintained constant. When the ammonia demand load changes, the heat input to the reactor is changed by increasing or decreasing the steam flow rate, thereby changing the reaction rate and ammonia production. However, due to the large size of the reactor and the long steam heat conduction time, the reactor temperature and rate change slowly, and the response speed to variable load instructions is slow, causing delays in the ammonia production system. When the unit increases load, the amount of ammonia injected at the SCR reaction is insufficient, resulting in excessive nitrogen oxide emissions; when the unit decreases load, excessive ammonia injection occurs, resulting in excessive ammonia slip. Summary of the Invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a pressure-regulated ammonium bicarbonate ammonia production reactor control system and method, which can improve the followability of the sodium bicarbonate ammonia production reactor to the unit load.

[0007] To achieve the above-mentioned object, the pressure-regulated ammonium bicarbonate ammonia production reactor control system of the present invention includes a product gas outlet valve, a product gas detector and a control system;

[0008] The product gas outlet of the ammonium bicarbonate ammonia production reactor is connected to the inlet of the product gas detector through the product gas outlet valve. A reactor pressure gauge is provided on the top of the sodium bicarbonate ammonia production reactor. A reactor pressure regulating valve is provided at the pressure regulating port on the top of the sodium bicarbonate ammonia production reactor. The control system is connected to the reactor pressure regulating valve, the reactor pressure gauge, the product gas detector and the product gas outlet valve.

[0009] The device also includes an ammonia absorption device, and the reactor pressure regulating valve is connected to the gas inlet on the bottom side of the ammonia absorption device.

[0010] An exhaust port is provided on the top of the ammonia absorption device.

[0011] A liquid outlet is provided at the bottom of the ammonia absorption device.

[0012] A nozzle is provided in the ammonia absorption device, and the nozzle is connected to the make-up water introduction pipe.

[0013] The outlet of the product gas detector is connected to the downstream system.

[0014] The control system includes a required ammonia production load input signal input module, a product gas regulation module and a reactor pressure regulation module;

[0015] The required ammonia production load input signal input module is connected to the input end of the product gas regulation module and the input end of the reactor pressure regulation module, the output end of the product gas detector is connected to the input end of the product gas regulation module, the output end of the product gas regulation module is connected to the control end of the product gas outlet valve, the output end of the reactor pressure gauge is connected to the input end of the reactor pressure regulation module, and the output end of the reactor pressure regulation module is connected to the control end of the reactor pressure regulation valve.

[0016] The product gas regulation module adopts PID control method.

[0017] The reactor pressure regulating module adopts PID control method.

[0018] The pressure-regulated ammonium bicarbonate ammonia production reactor control method of the present invention comprises the following steps:

[0019] 1) According to the operating data of the ammonium bicarbonate ammonia reactor, the relationship function f(x) between the reactor ammonia production load x (%) and the reactor pressure y (bar) is obtained, where y = 0.0031x 2 -0.76x+46;

[0020] 2) The desired ammonia production load N% is used as the target value for PID control, which is compared with the flow signal detected by the product gas detector. Based on the comparison result, the opening of the product gas outlet valve is determined through PID adjustment, and the product gas outlet valve is controlled accordingly;

[0021] 3) According to the required ammonia production load N%, the required reaction pressure of the reactor is determined by the relationship function f(x) between the reactor ammonia production load x (%) and the reactor pressure y (bar);

[0022] 4) According to the required reaction pressure of the reactor, the reactor pressure regulating valve is controlled by PID regulation to adjust the pressure in the sodium bicarbonate ammonia production reactor to achieve a stable balance between the pressure and ammonia production of the sodium bicarbonate ammonia production reactor.

[0023] The present invention has the following beneficial effects:

[0024] The pressure-regulated ammonium bicarbonate ammonia production reactor control system and method described in the present invention, during specific operation, utilizes the characteristic that the decomposition reaction rate of ammonium bicarbonate solution gradually decreases with increasing pressure, and uses PID regulation to control the ammonia production rate of the ammonium bicarbonate ammonia production reactor by regulating the pressure in the ammonium bicarbonate ammonia production reactor, thereby realizing the response of the ammonium bicarbonate ammonia production reactor to variable load instructions. The control method is simple to implement and has a rapid response, which can improve the followability of the ammonia production system to the unit load and enhance the stability of ammonia production. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a control logic diagram of the present invention;

[0026] Figure 2 The figure shows the relationship between the ammonia load produced by the secretion process and the required reaction pressure.

[0027] Figure 3 This is a system structure diagram of the present invention.

[0028] Among them, 1 is the required ammonia production load input signal input module, 2 is the product gas detector, 3 is the product gas outlet valve, 4 is the product gas regulating module, 5 is the reactor pressure gauge, 6 is the reactor pressure regulating module, 7 is the reactor pressure regulating valve, and 8 is the ammonia absorption device. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only embodiments of a part of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work should fall within the scope of protection of the present invention.

[0030] The accompanying drawings illustrate schematic diagrams of the structures of the disclosed embodiments of the present invention. These figures are not drawn to scale; for the purpose of clarity, some details are exaggerated and some details may be omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are merely exemplary and may deviate in practice due to manufacturing tolerances or technical limitations. Those skilled in the art may design regions / layers with different shapes, sizes, and relative positions as needed.

[0031] Example 1

[0032] refer to Figure 1 and Figure 3 The pressure-regulated ammonium bicarbonate ammonia production reactor control system of the present invention includes an ammonium bicarbonate ammonia production reactor, an ammonia absorption device 8, a required ammonia production load input signal input module 1, a product gas detector 2, a product gas outlet valve 3, a product gas regulation module 4, a reactor pressure gauge 5, a reactor pressure regulation module 6, a reactor pressure regulation valve 7 and an ammonia absorption device 8;

[0033] The product gas outlet of the ammonium bicarbonate ammonia production reactor is connected to the inlet of the product gas detector 2 through the product gas outlet valve 3, and the outlet of the product gas detector 2 is connected to the downstream system. A reactor pressure gauge 5 is provided on the top of the sodium bicarbonate ammonia production reactor, and a reactor pressure regulating valve 7 is provided at the pressure regulating port of the sodium bicarbonate ammonia production reactor, wherein the reactor pressure regulating valve 7 is connected to the gas inlet on the bottom side of the ammonia absorption device 8, which is used to absorb ammonia gas escaping from the ammonium bicarbonate ammonia production reactor. The gas inlet is located below the liquid level in the ammonia absorption device 8, the bottom of the ammonia absorption device 8 is provided with a liquid outlet, the top of the ammonia absorption device 8 is provided with an exhaust port, and a nozzle is provided in the ammonia absorption device 8, and the nozzle is connected to the make-up water inlet pipe.

[0034] The required ammonia production load input signal input module 1 is connected to the input end of the product gas regulating module 4 and the input end of the reactor pressure regulating module 6, the output end of the product gas detector 2 is connected to the input end of the product gas regulating module 4, the output end of the product gas regulating module 4 is connected to the control end of the product gas outlet valve 3, the output end of the reactor pressure gauge 5 is connected to the input end of the reactor pressure regulating module 6, and the output end of the reactor pressure regulating module 6 is connected to the control end of the reactor pressure regulating valve 7.

[0035] Example 2

[0036] The pressure-regulated ammonium bicarbonate ammonia production reactor control method of the present invention comprises the following steps:

[0037] 1) According to the operating data of the ammonium bicarbonate ammonia production reactor, the relationship function f(x) between the reactor ammonia production load x(%) and the reactor pressure y(bar) is obtained by fitting, as shown in FIG. Figure 2 As shown, where y = 0.0031x 2 -0.76x+46;

[0038] 2) Taking 80% of the required ammonia production load as the target value of PID control, the target value is compared with the flow signal detected by the product gas detector 2, and the opening of the product gas outlet valve 3 is determined by PID adjustment based on the comparison result, and the product gas outlet valve 3 is controlled accordingly;

[0039] 3) Based on the required ammonia production load of 80%, the required reactor pressure is determined to be 5.04 bar using the relationship function f(x) between the reactor ammonia production load x (%) and the reactor pressure y (bar);

[0040] 4) According to the required reaction pressure of the reactor, the reactor pressure regulating valve 7 is controlled by PID regulation to adjust the pressure in the sodium bicarbonate ammonia production reactor to achieve a stable balance between the pressure and ammonia production of the sodium bicarbonate ammonia production reactor.

[0041] Example 3

[0042] As described in Example 2, other conditions remain unchanged. When the ammonia production load is increased from 80% to 90%, the PID control increases the opening of the product gas outlet valve 3. The pressure of the sodium bicarbonate ammonia reactor drops in a short period of time, and the decomposition reaction rate of the ammonium bicarbonate solution increases. According to the relationship function y = 0.0031x 2 -0.76x+46 determines that the required reaction pressure for sodium bicarbonate ammonia production is 2.71 bar. Using this required reaction pressure of 2.71 bar as the target value for PID control, this is compared with the measurement signal from reactor pressure gauge 5. PID regulation determines the opening of reactor pressure regulating valve 7 to achieve a stable balance between pressure and ammonia production.

[0043] Example 4

[0044] As described in Example 2, other conditions remain unchanged. When the ammonia production load is reduced from 80% to 70%, the PID adjustment reduces the opening of the product gas outlet valve 3. The pressure of sodium bicarbonate ammonia production increases in a short time, and the decomposition reaction rate of ammonium bicarbonate solution decreases. Through the relationship function y=0.0031x 2-0.76x+46 can determine that the required reaction pressure of the sodium bicarbonate ammonia production reactor is 7.99 bar. The required reaction pressure of 7.99 bar is used as the target value of PID control and compared with the pressure measurement signal of the sodium bicarbonate ammonia production reactor. The opening of the reactor pressure regulating valve 7 is determined by PID adjustment to achieve a stable balance between the pressure and ammonia production of the sodium bicarbonate ammonia production reactor.

[0045] It should be noted that the present invention utilizes the characteristic that the decomposition reaction rate of ammonium bicarbonate solution gradually decreases with increasing pressure, and controls the ammonia production rate of the ammonium bicarbonate ammonia production reactor by adjusting the pressure in the ammonium bicarbonate ammonia production reactor, thereby realizing the response of the ammonium bicarbonate ammonia production reactor to the variable load instruction. The control method is simple to implement and has a rapid response, which can improve the adaptability of the ammonia production system to the unit load and enhance the stability of ammonia production. It should also be noted that the present invention has the following characteristics:

[0046] Shorten the response time: By utilizing the characteristic that the decomposition reaction rate of ammonium bicarbonate solution gradually decreases with increasing pressure, and establishing a functional relationship between load and reaction pressure based on the operating conditions of the ammonium bicarbonate ammonia production reactor, the required pressure of the ammonium bicarbonate ammonia production reactor can be directly obtained when the load is variable, and the opening of the reactor pressure regulating valve 7 is adjusted, which can significantly shorten the response time of the ammonia production system and improve the followability of the ammonia production reactor system to variable loads.

[0047] Fast pressure regulation: The rate of ammonia production reaction is controlled by adjusting the pressure in the ammonium bicarbonate ammonia production reactor, avoiding the heat conduction process of steam and the slow temperature change process, which can quickly respond to the ammonia production load.

[0048] Improved system safety: Because the decomposition reaction rate of ammonium bicarbonate solution decreases with increasing pressure, a negative feedback regulation process is implemented, resulting in high control precision and improved system stability and safety. In the event of an emergency shutdown, such as when the ammonia supply needs to be cut off or significantly reduced, the brief pressure increase within the ammonium bicarbonate reactor inhibits the continued decomposition reaction, preventing the danger of continued pressure increases within the system.

[0049] Ammonia recovery and reuse: The reactor pressure regulating valve 7 is connected to the ammonia absorption device 8. When the reactor pressure regulating valve 7 is opened, the escaped ammonia is absorbed by water and then circulated back to the ammonium bicarbonate ammonia absorption device 8 for reuse.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A pressure-regulated ammonium bicarbonate reactor control method, characterized in that: An ammonium bicarbonate ammonia production reactor control system based on pressure regulation, the pressure-regulated ammonium bicarbonate ammonia production reactor control system comprising a product gas outlet valve (3), a product gas detector (2) and a control system; The product gas outlet of the ammonium bicarbonate ammonia production reactor is connected to the inlet of the product gas detector (2) via a product gas outlet valve (3); a reactor pressure gauge (5) is provided on the top of the sodium bicarbonate ammonia production reactor; a reactor pressure regulating valve (7) is provided at the pressure regulating port on the top of the sodium bicarbonate ammonia production reactor; and a control system is connected to the reactor pressure regulating valve (7), the reactor pressure gauge (5), the product gas detector (2) and the product gas outlet valve (3); The following steps are involved: 1) According to the operating data of the ammonium bicarbonate ammonia reactor, the relationship function f(x) between the reactor ammonia production load x (%) and the reactor pressure y (bar) is obtained, where y = 0.0031x 2 -0.76x+46; 2) Taking the required ammonia production load N% as the target value of PID control, the target value is compared with the flow signal detected by the product gas detector (2), and the opening of the product gas outlet valve (3) is determined by PID regulation based on the comparison result, and the product gas outlet valve (3) is controlled accordingly; 3) According to the required ammonia production load N%, the required reaction pressure of the reactor is determined by the relationship function f(x) between the reactor ammonia production load x (%) and the reactor pressure y (bar); 4) According to the required reaction pressure of the reactor, the reactor pressure regulating valve (7) is controlled by PID regulation to adjust the pressure in the sodium bicarbonate ammonia production reactor, thereby achieving a stable balance between the pressure and ammonia production of the sodium bicarbonate ammonia production reactor.

2. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, wherein: The invention also comprises an ammonia absorption device (8), and the reactor pressure regulating valve (7) is connected to the gas inlet on the bottom side of the ammonia absorption device (8).

3. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, wherein: An exhaust port is provided on the top of the ammonia absorption device (8).

4. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, wherein: The bottom of the ammonia absorption device (8) is provided with a liquid outlet.

5. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, wherein: A nozzle is provided in the ammonia absorption device (8), and the nozzle is connected to the supplementary water introduction pipe.

6. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, characterized in that: The outlet of the product gas detector (2) is connected to the downstream system.

7. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, characterized in that: The control system comprises a required ammonia production load input signal input module (1), a product gas adjustment module (4) and a reactor pressure adjustment module (6); The required ammonia production load input signal input module (1) is connected to the input end of the product gas regulating module (4) and the input end of the reactor pressure regulating module (6); the output end of the product gas detector (2) is connected to the input end of the product gas regulating module (4); the output end of the product gas regulating module (4) is connected to the control end of the product gas outlet valve (3); the output end of the reactor pressure gauge (5) is connected to the input end of the reactor pressure regulating module (6); and the output end of the reactor pressure regulating module (6) is connected to the control end of the reactor pressure regulating valve (7).

8. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, characterized in that: The product gas regulating module (4) adopts a PID control method.

9. The pressure-regulated ammonium bicarbonate reactor control method according to claim 1, characterized in that: The reactor pressure regulating module (6) adopts a PID control method.

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