Urea hydrolysis ammonia system adaptive to peak-shaving boiler SCR denitration

Abstract

This invention relates to the field of waste gas treatment technology and discloses a urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers. The system comprises multiple urea solution reactor units, with a urea solution header pipe connected in parallel at the lower end of each reactor unit and a gas production header pipe connected in parallel at the upper end. The system consists of multiple urea solution reactor units connected in parallel. Each reactor unit can independently control the urea solution and heating steam involved in the reaction within the unit without affecting the operating parameters of other reactor units. By installing a regulating valve on the urea solution side of the hydrolysis reaction, the fluctuations that should occur on the gas production side in the current hydrolysis ammonia production reactor are limited to the reaction solution side, thus ensuring stable gas production pressure and concentration even when ammonia demand changes frequently.

Description

Technical Field

[0001] This invention belongs to the field of waste gas treatment technology, specifically a urea hydrolysis ammonia production system adapted to SCR denitrification of peak-shaving boilers. Background Technology

[0002] Coal combustion in coal-fired power plants produces large amounts of flue gas, including significant amounts of nitrogen oxides (NOx), which pollute the atmosphere. A common solution is to install a flue gas denitrification device at the boiler's tail end, using selective catalytic reduction (SCR) to remove NOx from the flue gas and convert it into non-toxic and harmless nitrogen (N2) and water (H2O), thereby meeting pollutant emission requirements.

[0003] In selective catalytic reduction (SCR), the ammonia (NH3) required for denitrification is typically supplied in three forms: liquid ammonia, ammonia water, and urea conversion. Liquid ammonia and ammonia water are classified as hazardous chemicals. National regulations govern the storage, use, and transportation of liquid ammonia and ammonia water.

[0004] Industrial urea is a white crystalline granule, not classified as a hazardous chemical, making it easy to store and transport, and posing no safety hazard due to leakage. The production of ammonia from urea is the most common method in denitrification processes at coal-fired power plants both domestically and internationally. Among these methods, the urea solution hydrolysis ammonia production process has advantages in terms of economy, safety, and operating costs, and is therefore adopted by most power plants in China.

[0005] Domestic hydrolysis reactors mostly adopt a reaction vessel structure. A urea solution with a mass fraction of 40%-60% is introduced into the reaction vessel. The heat to ensure the urea hydrolysis reaction is carried out is provided by heating steam through the coils in the reaction vessel.

[0006] The urea hydrolysis reactor operates under set temperature and pressure conditions, producing a mixture of ammonia, carbon dioxide, and water vapor. When the urea solution has a mass percentage of 50%, the reactor liquid phase temperature is around 145℃, and the gas-side pressure is 0.4-0.6MPa, the mass percentage of ammonia in the mixture is approximately 37%. The output of the ammonia mixture is controlled by an outlet regulating valve. After being diluted by dilution air to a mass percentage of ammonia below 8%, it is then distributed to the SCR catalytic reactor side for catalytic reduction reaction.

[0007] Current issues:

[0008] Nitrogen oxides in flue gas need to react with ammonia in the presence of a catalyst to produce nitrogen and water. If the amount of ammonia is insufficient, the amount of nitrogen oxides removed will be insufficient, resulting in low denitrification efficiency and environmental pollution.

[0009] Excessive ammonia gas can lead to ammonia escape: the escaped ammonia wastes funds and pollutes the environment; it corrodes the catalyst module, causing catalyst deactivation (i.e., failure) and blockage, greatly shortening the catalyst's lifespan; the escaped ammonia reacts with SO3 in the flue gas to form ammonium sulfate (corrosive and adhesive), causing blockage and corrosion of the heat storage components in the air preheater downstream of the denitrification process; excess escaped ammonia is absorbed by fly ash, making the aerated concrete blocks (ash bricks) unsellable; and excess ammonia absorbed by the desulfurization tower will escape into the atmosphere after subsequent desulfurization wastewater treatment, continuing to pollute the environment.

[0010] The "Technical Guidelines for Flue Gas Denitrification in Thermal Power Plants" (DL / 296-2011) stipulates that "the ammonia slip concentration of denitrification units using SCR technology should preferably not exceed 2.3 mg / m3".

[0011] Urea hydrolysis to ammonia production is a highly complex physicochemical process with intricate chemical mechanisms. The reaction involves multiple components, and its rate is affected by concentration, temperature, and pressure. Furthermore, the produced gas is a mixture of ammonia, carbon dioxide, and water vapor, creating a gas-liquid-solid equilibrium. Under conditions of minimal boiler load variation and stable or slowly fluctuating ammonia demand, the urea hydrolysis reactor, after adaptive operation adjustments, can output a stable ammonia gas supply. This process has minimal impact on the SCR denitrification system.

[0012] However, many modern power plant boilers operate in conjunction with the power grid for deep peak shaving, causing boiler load variation rates to fluctuate within the range of 50%-100% of the boiler's maximum continuous evaporation rate (BMCR) for short periods. Some boilers can even reach a minimum load of 30% BMCR. These load changes require coordinated adjustments to coal consumption, forced draft, induced draft, boiler feedwater, and steam regulation. Changes in coal consumption and forced / induced draft will lead to variations in flue gas volume and composition, as well as SCR-side pressure and temperature. To ensure SCR operating efficiency and prevent ammonia escape, the ammonia production system needs to provide values ​​that match the ammonia demand in real time.

[0013] To maintain the continuous and stable operation of the ammonia production process, existing urea hydrolysis reactors generally employ two methods: constant pressure operation and sliding pressure operation.

[0014] 1. Constant Pressure Operation: The ammonia output regulating valve automatically adjusts the ammonia output based on changes in boiler load, flue gas volume, and flue gas composition. Changes in ammonia output directly affect the phase equilibrium of the reaction unit, causing variations in the pressure on the ammonia-gas mixture side. Constant pressure regulation is achieved by adjusting the solution temperature within the reactor using steam. This process simultaneously affects parameters such as the hydrolysis reaction rate, gas production rate, and gas-side pressure. Through PID control, the gas-side pressure is gradually stabilized to the set value, allowing the urea hydrolysis reaction to reach the corresponding equilibrium state. Simultaneously with temperature regulation, the liquid level in the unit is also controlled via the urea feed pump.

[0015] 2. Sliding Pressure Operation: The ammonia output regulating valve automatically adjusts the ammonia output based on changes in boiler load, flue gas volume, and flue gas composition. Changes in ammonia output directly affect the phase balance of the reaction unit, causing pressure variations on the ammonia-gas mixture side. The goal of sliding pressure regulation is to maintain a constant solution temperature. For example, if the ammonia regulating valve is opened wider, the gas-side pressure decreases, increasing the chemical reaction rate and solution evaporation rate. This leads to a decrease in solution temperature. In this case, PID control is needed to increase the steam flow and gradually adjust the solution temperature back to the set value. This process of solution temperature adjustment directly causes fluctuations in the hydrolysis reaction rate, resulting in fluctuations in gas production and pressure fluctuations on the gas production side.

[0016] Power plants generally recommend constant pressure operation, which provides a rapid response to the reaction pressure. The heating steam valves are quickly adjusted to their positions via a PID control module, resulting in minimal fluctuations in reactor pressure and temperature. (However, under low load conditions, considering the characteristics of urea hydrolysis reaction with temperature variation—specifically, between 120-160 degrees Celsius, exhibiting slow, vigorous, and exponentially increasing reaction rates—significant pressure fluctuations may still occur when adjusting the ammonia output valve in the low load zone, taking into account the thermal inertia of the solution within the tank.)

[0017] Currently, hydrolysis reactors, regardless of the operating mode, suffer from issues such as pressure fluctuations in the ammonia mixture source, ammonia concentration fluctuations, and even overpressure emissions of the ammonia mixture. Furthermore, they cannot quickly and timely match the ammonia demand during deep peak-shaving operation of the boiler.

[0018] To address this problem, the present invention provides a urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers. Summary of the Invention

[0019] In order to overcome the shortcomings of the prior art, the present invention provides a urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers. This system effectively solves the problem that the pressure and concentration on the gas production side of the existing urea hydrolysis device change drastically with the load of the peak-shaving boiler, resulting in uncontrollable ammonia supply, reduced SCR efficiency, or increased ammonia escape.

[0020] To achieve the above objectives, the present invention provides the following technical solution: a urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers, comprising multiple urea solution reactor units, with a urea solution header pipe connected in parallel at the lower ends of the multiple urea solution reactor units, and a gas generation header pipe connected in parallel at the upper ends of the multiple urea solution reactor units. A reflux water tank is provided between the urea solution header pipe and the gas generation header pipe, with one end of the reflux water tank connected to the urea solution header pipe and the other end of the reflux water tank connected to the gas generation header pipe through a gas balance pipe. A reflux liquid header pipe is connected between the multiple urea solution reactor units, with one end of the reflux liquid header pipe connected to the reflux water tank, and the gas generation header pipe connected to the reflux liquid header pipe through a drain pipe.

[0021] Preferably, the input end of the urea solution main pipe is connected to a filter, a feed pump is connected to one side of the filter, and a check valve is connected to one side of the feed pump.

[0022] Preferably, a safety valve is connected to the upper end of the gas production header, a secondary gas-water separator is connected to one side of the upper end of the gas production header, and an ammonia outlet regulating valve is connected to the upper end of the secondary gas-water separator.

[0023] Preferably, the urea solution reactor unit includes a tubular heat exchanger, with a unit circulating pump connected to the lower end of the tubular heat exchanger, a unit regulating valve connected to the upper end of the tubular heat exchanger, a unit gas-liquid separator connected to the upper end of the unit regulating valve, a steam condensate discharge valve connected to one side of the tubular heat exchanger, and an inlet steam regulating valve connected to one side of the tubular heat exchanger.

[0024] Preferably, the unit gas-water separator has a heated urea solution inlet at the center of its bottom, an anti-impact baffle is provided above the heated urea solution inlet and inside the unit gas-water separator, a gas production port is provided at the top of the unit gas-water separator, a return liquid port is provided on one side of the bottom of the unit gas-water separator, an open-hole fixed isolation plate is connected inside the unit gas-water separator, a gas-water separation wire mesh is filled below the open-hole fixed isolation plate, and a mixed gas space is provided above the open-hole fixed isolation plate.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] The system of this invention consists of multiple urea solution reactor units connected in parallel. Each reaction unit can independently control the urea solution and heating steam participating in the reaction within the unit without affecting the operating parameters of other reaction units. By installing a regulating valve on the urea solution side of the hydrolysis reaction, the fluctuations that should occur on the gas production side in the current hydrolysis ammonia production reactor are limited to the reaction solution side. Thus, even when the ammonia demand changes frequently, a stable gas production pressure and concentration can still be obtained. This solves the problem of pressure and concentration fluctuations on the ammonia production side caused by large and frequent fluctuations in the ammonia demand of SCR in existing urea hydrolysis reaction systems under deep peak shaving conditions of coal-fired boilers. The stable urea hydrolysis ammonia mixture gas source properties of the system of this invention provide the necessary conditions for precise control of SCR ammonia supply, improvement of denitrification efficiency, and control of ammonia escape. Attached Figure Description

[0027] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0028] In the attached diagram:

[0029] Figure 1 This invention relates to a combined system device for urea hydrolysis to ammonia production.

[0030] Figure 2 This is a schematic diagram of the structure of the urea solution reactor unit of the present invention;

[0031] Figure 3 This is a schematic diagram of the structure of the unit gas-water separator of the present invention;

[0032] In the diagram: 1. Filter; 2. Feed pump; 3. Check valve; 4. Urea solution main pipe; 5. Urea solution reactor unit; 5-1. Unit circulation pump; 5-2. Steam drain valve; 5-3. Inlet steam regulating valve; 5-4. Unit regulating valve; 5-5. Unit gas-liquid separator; 5-5-1. Heated urea solution inlet; 5-5-2. Gas-liquid separation wire mesh; 5-5-3. Perforated fixed isolation plate; 5-5-4. Mixed gas space; 5-5-5. Gas production port; 5-5-6. Impact baffle; 5-5-7. Return liquid port; 5-6. Tubular heat exchanger; 6. Return liquid main pipe; 7. Return water tank; 8. Gas production main pipe; 8-1. Secondary gas-liquid separator; 8-2. Safety valve; 9. Ammonia outlet regulating valve; 10. Gas balance pipe; 11. Drain pipe. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] Example 1, by Figures 1-3 The present invention includes multiple urea solution reactor units 5, with urea solution header 4 connected in parallel at the lower ends of the multiple urea solution reactor units 5, and gas generation header 8 connected in parallel at the upper ends of the multiple urea solution reactor units 5. A return water tank 7 is provided between the urea solution header 4 and the gas generation header 8. One end of the return water tank 7 is connected to the urea solution header 4, and the other end of the return water tank 7 is connected to the gas generation header 8 through a gas balance pipe 10. A return liquid header 6 is connected between the multiple urea solution reactor units 5, with one end of the return liquid header 6 connected to the return water tank 7. The gas generation header 8 is connected to the return liquid header 6 through a drain pipe 11.

[0035] Specifically, the input end of the urea solution main pipe 4 is connected to a filter 1, a feed pump 2 is connected to one side of the filter 1, and a check valve 3 is connected to one side of the feed pump 2.

[0036] A safety valve 8-2 is connected to the upper end of the gas production main pipe 8, and a secondary gas-water separator 8-1 is connected to one side of the upper end of the gas production main pipe 8. An ammonia outlet regulating valve 9 is connected to the upper end of the secondary gas-water separator 8-1.

[0037] Specifically, the urea solution reactor unit 5 includes a tubular heat exchanger 5-6, a unit circulating pump 5-1 connected to the lower end of the tubular heat exchanger 5-6, a unit regulating valve 5-4 connected to the upper end of the tubular heat exchanger 5-6, a unit gas-liquid separator 5-5 connected to the upper end of the unit regulating valve 5-4, a steam condensate discharge valve 5-2 connected to one side of the tubular heat exchanger 5-6, and an inlet steam regulating valve 5-3 connected to one side of the tubular heat exchanger 5-6.

[0038] Specifically, the unit gas-water separator 5-5 has a heated urea solution inlet 5-5-1 at the center of its bottom, an anti-impact baffle 5-5-6 above the heated urea solution inlet 5-5-1 and inside the unit gas-water separator 5-5, a gas production port 5-5-5 at the top of the unit gas-water separator 5-5, a return liquid port 5-5-7 on one side of the bottom of the unit gas-water separator 5-5, an open-hole fixed isolation plate 5-5-3 connected inside the unit gas-water separator 5-5, a gas-water separation wire mesh 5-5-2 filled below the open-hole fixed isolation plate 5-5-3, and a mixed gas space 5-5-4 above the open-hole fixed isolation plate 5-5-3.

[0039] Working principle: I. Steady-state working process:

[0040] Prepare a urea aqueous solution with a mass percentage concentration of 40-60% in advance at a temperature of 60-80℃;

[0041] The urea solution is pumped by the feed pump 2 and filtered by the filter 1 into the urea solution header 4. The solution is then distributed into each urea solution reactor unit 5 and the return water tank 7 through the header 4. The water volume is controlled to the designed liquid level of the water supply and ammonia production combination unit. At this time, the liquid level of the urea solution reactor unit 5 is about 5-10cm below the position of the perforated fixed isolation plate 5-5-3.

[0042] The unit circulation pump 5-1 is turned on. The urea solution enters the unit gas-liquid separator 5-5 through the heating tube bundle in the urea solution reactor unit 5, the unit regulating valve 5-4, and then returns to the return water tank 7 through the return liquid port 5-5-7. Finally, it returns to the mother liquor pipe 4 and re-enters the inlet of the unit circulation pump 5-1 to form a circulation loop.

[0043] The inlet steam regulating valves 5-3 of each urea solution reactor unit 5 are gradually opened. Steam enters the urea solution in the shell-side heating tube bundle of the urea solution reactor unit 5 through the inlet. After the urea solution is heated to above 90°C, it begins to slowly undergo hydrolysis reaction, generating a mixture of ammonia, carbon dioxide, and water. When the solution containing the reaction gas circulates through the unit gas-liquid separator 5-5, it collides with the gas-liquid separation wire mesh 5-5-2. The water flow is in a strong turbulent state, and separation is achieved by relying on the different upward flow velocities of the gas and liquid after separation.

[0044] The separated mixed gas is collected in the gas production header 8 through the mixed gas space 5-5-4, and then sent to the boiler SCR system through the secondary gas-water separator 8-1 and the ammonia outlet regulating valve 9. The water separated in the gas production header 8 is returned to the return water tank 7 through the drain pipe 11.

[0045] Unreacted urea solution flows through the reflux header 6 into the reflux tank 7 for the next cycle.

[0046] The gas space of the return water tank 7 is connected to the gas production header 8 through the gas balance pipe 10 to prevent problems such as poor water return caused by gas side pressure. At the same time, the hydrolysis reaction that continues in the solution of the return water tank 7 will produce ammonia mixed gas, which will also directly enter the gas production header 8 through the gas balance pipe 10.

[0047] The SCR denitrification system controls the ammonia demand based on the flue gas volume and nitrogen oxide concentration. Changes in the ammonia demand are controlled by the ammonia outlet regulating valve 9.

[0048] As the urea hydrolysis reaction proceeds, the amount of urea solution will continuously decrease, and the feed pump 2 will adjust the amount of water added according to the system liquid level via frequency conversion.

[0049] When the system is in steady-state operation, under the condition that the concentration of the inlet ammonia solution, the steam parameters, and the amount of ammonia used remain unchanged, it will enter a dynamic equilibrium state in which the pressure, temperature, and flow rate all change very little.

[0050] II. Deep Peak Shaving Workflow:

[0051] When a boiler is deeply shaving its load, there are three typical operating conditions: rapid load reduction, rapid load increase, and rapid load fluctuations including both reduction and increase. For the above three operating conditions, the device of the present invention performs the following operation regulation.

[0052] The invention example uses a coal-fired boiler with 20 urea solution reactor units 5. The ammonia production of each urea solution reactor unit 5 corresponds to the ammonia demand of the boiler at 5% BMCR load.

[0053] 1. Rapid load reduction condition

[0054] The invention device adjusts the boiler load by rapidly reducing it by 15% BMCR. During the boiler load change adjustment cycle, the unit regulating valves 5-4 of the three urea solution reactor units 5 are adjusted accordingly. The unit regulating valve 5-4 before the unit gas-liquid separator 5-5 of the urea solution reactor unit 5 gradually closes, and the opening of the inlet steam regulating valve 5-3 and the frequency adjustment of the unit circulating pump 5-1 are adjusted synchronously until they are closed.

[0055] During the boiler load change cycle, the ammonia production load of the three reaction units decreased by 15%.

[0056] For example, if the boiler load decreases by 5% within 1 minute, the steam will be shut off within 1 minute, and the heating amount will decrease by 5%; the unit circulation pump 5-1 will gradually stop, and the unit regulating valve 5-4 will gradually close.

[0057] The solution remaining in the heating tube of urea solution reactor unit 5 will continue to undergo a small amount of hydrolysis reaction due to the residual heat of the shell-side steam. The generated gas is shut off by the unit regulating valve 5-4 and remains in the pipeline of urea solution reactor unit 5, thus not directly affecting the gas pressure. The increased gas pressure in the heating tube causes some gas to dissolve in the urea solution. The increased pressure of the undissolved gas causes the urea solution in the tube to flow back to the solution header 4, and is then transported by the other unit circulation pump 5-1 to other urea solution reactor units 5. After the next round of venting, it enters the return water tank 7. The feed pump 2, which is interlocked with the liquid level of the return water tank 7, will simultaneously reduce the urea solution feed rate according to the tank level. The main regulation involves reducing the steam in this reaction unit to a stop and reducing the urea aqueous solution circulation rate in the regulating unit to a stop. The controlled reduction in ammonia gas corresponds one-to-one with the reduction in boiler load, maintaining a balance between gas production and consumption. The operating parameters of the other reaction units remain unchanged. Therefore, the pressure fluctuations and gas concentration changes on the gas side are approximately zero.

[0058] 2. Rapid load increase condition

[0059] If the boiler load increases rapidly by 15% BMCR, the three urea solution reactor units 5 will work together to regulate the total ammonia production by 15%.

[0060] Analysis was conducted on one of the urea solution reactor units, unit 5:

[0061] Since the solution side of urea solution reactor unit 5 is connected to the mother liquor pipe 4, it is always in a hot standby state. When the boiler load increases, the ammonia demand for SCR denitrification increases, the ammonia outlet regulating valve 9 opens wider, and the gas pressure in the gas side space decreases. Opening the unit regulating valve 5-4 of urea solution reactor unit 5 allows the reaction gas temporarily stored in the reactor heating tube bundle to be carried out by the circulating liquid. After passing through the unit gas-liquid separator 5-5, the ammonia mixture is quickly replenished to stabilize the gas side pressure. Subsequently, taking advantage of the small heat capacity of the urea solution participating in the heating reaction in the unit reactor, the high-temperature solution in the urea solution mother pipe 4 is rapidly heated by steam to the high reaction rate reaction range, which can quickly increase the gas production.

[0062] Urea solution feed pump 2, with frequency conversion, increases the water supply and replenishes the reaction solution to the designed liquid level.

[0063] In addition, to meet the heat requirements of rapid gas production, a margin of 10-20% should be reserved for the heat exchange area or the maximum steam volume when designing the reaction unit.

[0064] 3. Continuous fluctuation control

[0065] The boiler load fluctuates between rapid increases and rapid decreases. When the load decreases rapidly, the unit regulating valve 5-4 and the inlet steam regulating valve 5-3 are closed simultaneously to balance the gas production and gas consumption, thus quickly balancing the gas-side pressure. The urea gas produced due to waste heat is temporarily stored in the urea solution pipeline. When the load increases rapidly, the unit regulating valve 5-4 and the inlet steam regulating valve 5-3 are opened simultaneously. First, the temporarily stored gas in the heating pipe is released, and the pressure is reduced. Then, taking advantage of the small heat capacity of the urea solution participating in the reaction in the unit reaction device, the urea solution in the pipe can be quickly heated to the rapid gas production temperature range, increasing the gas production to within the boiler's ammonia load and quickly restoring the original equilibrium state.

[0066] This embodiment is merely an example. For systems with different ammonia requirements, different system configuration modes can be adopted, including using a main circulation pump header mode to replace the unit circulation pump, and using a main gas-side gas-water separation header mode to replace the unit module separate gas-water separation mode, etc. Any adjustments to the system device of the present invention as described above should fall within the scope of protection of the present invention.

Claims

1. A urea hydrolysis ammonia production system adapted for peak shaving boiler SCR denitration, comprising a plurality of urea solution reactor units (5), characterized in that: A urea solution reactor unit (5) is connected in parallel at the lower end to a urea solution main pipe (4), and a gas generation main pipe (8) is connected in parallel at the upper end of the urea solution reactor unit (5). A return water tank (7) is provided between the urea solution main pipe (4) and the gas generation main pipe (8). One end of the return water tank (7) is connected to the urea solution main pipe (4), and the other end of the return water tank (7) is connected to the gas generation main pipe (8) through a gas balance pipe (10). A return liquid main pipe (6) is connected between the urea solution reactor units (5). One end of the return liquid main pipe (6) is connected to the return water tank (7), and the gas generation main pipe (8) is connected to the return liquid main pipe (6) through a drain pipe (11). The urea solution reactor unit (5) includes a tubular heat exchanger (5-6), a unit circulating pump (5-1) connected to the lower end of the tubular heat exchanger (5-6), a unit regulating valve (5-4) connected to the upper end of the tubular heat exchanger (5-6), a unit gas-water separator (5-5) connected to the upper end of the unit regulating valve (5-4), a steam condensate discharge valve (5-2) connected to one side of the tubular heat exchanger (5-6), and an inlet steam regulating valve (5-3) connected to one side of the tubular heat exchanger (5-6).

2. The urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers according to claim 1, characterized in that: The input end of the urea solution main pipe (4) is connected to a filter (1), a feed pump (2) is connected to one side of the filter (1), and a check valve (3) is connected to one side of the feed pump (2).

3. The urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers according to claim 1, characterized in that: The upper end of the gas production main pipe (8) is connected to a safety valve (8-2), and a secondary gas-water separator (8-1) is connected to one side of the upper end of the gas production main pipe (8). The upper end of the secondary gas-water separator (8-1) is connected to an ammonia outlet regulating valve (9).

4. The urea hydrolysis ammonia production system adapted to SCR denitrification in peak-shaving boilers according to claim 1, characterized in that: The unit gas-water separator (5-5) has a heated urea solution inlet (5-5-1) at the center of its bottom. An anti-impact baffle (5-5-6) is provided above the heated urea solution inlet (5-5-1) and inside the unit gas-water separator (5-5). A gas production port (5-5-5) is provided at the top of the unit gas-water separator (5-5). A return liquid port (5-5-7) is provided on one side of the bottom of the unit gas-water separator (5-5). An open-hole fixed isolation plate (5-5-3) is connected inside the unit gas-water separator (5-5). A gas-water separation wire mesh (5-5-2) is filled below the open-hole fixed isolation plate (5-5-3). A mixed gas space (5-5-4) is provided above the open-hole fixed isolation plate (5-5-3).

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