Flue gas SCR denitration urea hydrolysis dilution air heating system

Abstract

The utility model relates to a flue gas SCR denitration urea hydrolysis dilution air heating system. The system comprises key assemblies such as an SCR reactor, a dilution fan and a urea solvent pool. A urea particle storage tank is mounted above the urea solvent pool, and urea particles are controlled to flow into the solvent pool through an electromagnetic valve. Desalted water in the demineralized water tank is injected into the solvent pool through the electric control water pump, and urea particles are dissolved to form a urea solution. The solution is sent to an electric heating tower through a water pump to be heated to 600 DEG C to generate ammonia gas, and the ammonia gas flows into an ammonia gas kettle through a pipeline and then is pumped into an ammonia gas blower through a sucking pump. Dilution air generated by the dilution fan is preheated by the heat exchanger and then is fed into the flue. Ammonia is fed into the flue by the ammonia blower to be mixed with the hot dilution air and then enters the SCR reactor. According to the system, hydrolysis of urea and supply of ammonia gas are effectively achieved, a necessary reducing agent is provided for SCR denitration, and meanwhile reaction uniformity and efficiency are guaranteed through heating and adjusting of dilution air. Intelligent monitoring and management ensure the treatment efficiency and the denitration effect, and the operation cost is optimized.

Description

TECHNICAL FIELD

[0001] The technical field of the utility model relates to the industrial environmental protection technical field, especially relates to a flue gas SCR denitration urea hydrolysis dilution air heating system. BACKGROUND

[0002] Thermal power plants, as traditional air pollution sources, emit nitrogen oxides (NOx) which become the focus of control. Selective catalytic reduction (SCR) flue gas denitration technology is widely used to reduce NOx emissions due to its high efficiency and reliability. In the SCR flue gas denitration system, the choice of reducing agent is crucial. Common reducing agents include ammonia water, liquid ammonia, and ammonia produced by urea. Although liquid ammonia has certain advantages in terms of operating cost and investment cost, its potential safety risks limit its application. In contrast, urea, as a raw material for ammonia production, is gradually gaining more favor due to its non-toxicity, safety in transportation and storage, and other advantages.

[0003] Urea ammonia production mainly includes urea hydrolysis and urea pyrolysis processes. The urea hydrolysis process involves reacting urea solution at specific temperature and pressure conditions to produce ammonia, carbon dioxide, and water vapor. This process usually occurs at about 150℃. To achieve the required ammonia concentration for denitration, the generated mixed gas must be mixed with dilution air. However, when the temperature of the mixed gas is below 130℃, the reverse reaction occurs, producing ammonium carbamate crystals, which can cause pipe and equipment blockage. Therefore, ensuring that the temperature of the mixed gas remains between 150-180℃ is crucial to prevent blockage and maintain normal operation of the system.

[0004] Currently, common methods for heating dilution air include electric heating and steam heating. However, electric heating consumes a large amount of electricity, while steam heating consumes a large amount of high-quality steam, both of which are not economical in terms of operating costs. This challenge has prompted the industry to seek more efficient and economical solutions to ensure that the SCR flue gas denitration system meets increasingly stringent environmental protection requirements while also achieving economic operation. UTILITY MODEL CONTENT

[0005] Therefore, in order to improve operating economy and avoid wasting high-grade energy, the present application proposes a flue gas SCR denitration urea hydrolysis dilution air heating system.

[0006] To achieve the above-mentioned purposes, the present application adopts the following solutions:

[0007] A flue gas SCR denitrification urea hydrolysis dilution air heating system includes an SCR reactor. The system is characterized by comprising a dilution fan, a urea solvent tank, a urea granule storage tank, and a demineralized water tank. The urea solvent tank is connected to an electric heating tower via a water supply pipe. The electric heating tower is connected to an ammonia reactor via a Z-shaped pipe. The ammonia reactor is connected to an ammonia blower via a gas supply pipe. The dilution fan is connected to a heat exchanger via an air supply pipe. The SCR reactor has a flue, which is connected to the ammonia blower and heat exchanger via air supply pipes.

[0008] Preferably, the urea granule storage tank is installed above the urea solvent pool, the urea granule storage tank is equipped with an electromagnetic valve, the urea granule storage tank stores urea granules, and the urea granules flow into the urea solvent pool under the control of the electromagnetic valve.

[0009] Preferably, a water supply pipe is provided between the demineralized water tank and the urea solvent pool, the water supply pipe is equipped with an electrically controlled water pump, the demineralized water tank stores demineralized water, and the demineralized water is injected into the urea solvent pool by the electrically controlled water pump.

[0010] Preferably, the urea particles flowing into the urea solvent pool dissolve into a urea solution after being injected with demineralized water, and the urea solution is pumped out by a water pump and flows into an electric heating tower.

[0011] Preferably, the electric heating tower electrically heats the incoming urea solution, and the urea solution is heated to 600°C to generate a large amount of ammonia gas, which flows into the ammonia gas reactor through a Z-shaped pipe.

[0012] Preferably, an air extraction pump is provided between the ammonia gas reactor and the ammonia gas blower, and the ammonia gas in the ammonia gas reactor is drawn into the ammonia gas blower by the air extraction pump.

[0013] Preferably, the dilution fan generates a large amount of dilution air and sends it to a heat exchanger through an air supply pipe. The heat exchanger preheats the dilution air and sends it into the flue.

[0014] Preferably, the ammonia blower sends ammonia into the flue, where it mixes with the hot dilution air inside the flue and finally enters the SCR reactor.

[0015] The beneficial effects of this utility model are as follows:

[0016] 1. This application achieves rapid and continuous ammonia production and flue gas mixing through a highly efficient urea pyrolysis process and precise ammonia mixing control. Simultaneously, using urea as the ammonia source reduces transportation and storage risks and improves operational safety. 2. This application utilizes a heat exchanger to recover waste heat from the flue gas to preheat the dilution air, reducing additional energy requirements. Simultaneously, maintaining the system temperature between 150 and 180°C effectively prevents reverse reactions and system blockage, ensuring long-term stable operation.

[0017] 3. The system design takes into account economic operation, reduces power consumption and high-quality steam consumption, lowers operating costs, and at the same time helps the factory meet strict environmental standards by reducing NOx emissions, thus improving environmental friendliness.

[0018] 4. The modular design makes the system easy to install, maintain and upgrade, and can adjust the processing capacity according to the actual needs of different factories, increasing the system's applicability and flexibility, while also facilitating daily maintenance and repair. Attached Figure Description

[0019] Figure 1 This is a structural diagram of a flue gas SCR denitrification urea hydrolysis dilution air heating system according to the present invention.

[0020] In the diagram: 1. SCR reactor; 2. Dilution blower; 3. Urea solvent tank; 4. Urea granule storage tank; 5. Demineralized water tank; 6. Electric heating tower; 7. Ammonia reactor; 8. Ammonia blower; 9. Heat exchanger; 10. Flue; 11. Solenoid valve; 12. Air pump. Detailed Implementation

[0021] A flue gas SCR denitrification urea hydrolysis dilution air heating system includes an SCR reactor 1. It is characterized by comprising a dilution fan 2, a urea solvent tank 3, the urea solvent tank 3 being equipped with a urea granule storage tank 4 and a demineralized water tank 5, the urea solvent tank 3 being connected to an electric heating tower 6 via a water supply pipe, the electric heating tower 6 being connected to an ammonia gas reactor 7 via a Z-shaped pipe, the ammonia gas reactor 7 being connected to an ammonia gas blower 8 via an air supply pipe, the dilution fan 2 being connected to a heat exchanger 9 via an air supply pipe, and the SCR reactor 1 having a flue 10, which is connected to the ammonia gas blower 8 and the heat exchanger 7 via air supply pipes.

[0022] The urea granule storage tank 4 is installed above the urea solvent pool 3. The urea granule storage tank 4 is equipped with an electromagnetic valve 11. The urea granule storage tank 4 stores urea granules, and the urea granules flow into the urea solvent pool 3 under the control of the electromagnetic valve.

[0023] A water supply pipe is provided between the demineralized water tank 5 and the urea solvent tank 3. The water supply pipe is equipped with an electrically controlled water pump. The demineralized water tank 5 stores demineralized water, which is injected into the urea solvent tank 3 by the electrically controlled water pump.

[0024] Urea particles flowing into urea solvent pool 3 dissolve into urea solution after being injected with demineralized water. The urea solution is then pumped out by a water pump and flows into electric heating tower 6.

[0025] The electric heating tower 6 electrically heats the incoming urea solution. When the urea solution is heated to 600°C, a large amount of ammonia gas is generated. The ammonia gas flows into the ammonia gas reactor 7 through the Z-shaped pipe.

[0026] An air pump 12 is installed between the ammonia gas reactor 7 and the ammonia gas blower 8. The ammonia gas in the ammonia gas reactor 7 is drawn into the ammonia gas blower 8 by the air pump 9.

[0027] The dilution fan 2 generates a large amount of dilution air and sends it into the heat exchanger 7 through the air supply duct. The heat exchanger 7 preheats the dilution air and sends it into the flue 10.

[0028] Ammonia gas blower 8 sends ammonia gas into the flue, where it mixes with the hot dilution air in the flue 10 and finally enters the SCR reactor 1.

Claims

1. A flue gas SCR denitration urea hydrolysis dilution air heating system comprising an SCR reactor (1), characterized in that, The device comprises a dilution fan (2), a urea solvent pool (3), a urea particle storage tank (4) and a desalted water tank (5) installed on the urea solvent pool (3), the urea solvent pool (3) is connected with an electric heating tower (6) through a water feeding pipeline, the electric heating tower (6) is connected with an ammonia gas kettle (7) through an ethylene pipeline, the ammonia gas kettle (7) is connected with an ammonia gas fan (8) through a gas feeding pipeline, the dilution fan (2) is connected with a heat exchanger (9) through an air feeding pipeline, and the SCR reactor (1) is provided with a flue (10) connected with the ammonia gas fan (8) and the heat exchanger (9) through air feeding pipelines.

2. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 1, characterized in that, The urea particle storage tank (4) is installed above the urea solvent pool (3), the urea particle storage tank (4) is provided with an electromagnetic valve, and the urea particle storage tank (4) stores urea particles, which are controlled to fall into the urea solvent pool (3) by the electromagnetic valve (11).

3. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 1, characterized in that, The desalted water tank (5) is connected with the urea solvent pool (3) through a water feeding pipeline, the water feeding pipeline is provided with an electric control water pump, the desalted water tank (5) stores desalted water, and the desalted water is injected into the urea solvent pool (3) by the electric control water pump.

4. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 2 or 3, characterized in that, The urea particles flowing into the urea solvent pool (3) are dissolved into urea solution after being injected with desalted water, and the urea solution is pumped out and flows into the electric heating tower (6).

5. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 2 or 3, characterized in that, The electric heating tower (6) electrically heats the urea solution flowing in, and the urea solution is heated to 600 DEG C to generate a large amount of ammonia gas, which flows into the ammonia gas kettle (7) through the ethylene pipeline.

6. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 1, characterized in that, The ammonia gas kettle (7) is provided with a gas pump (12) connected with the ammonia gas fan (8), and the ammonia gas in the ammonia gas kettle (7) is pumped into the ammonia gas fan (8) by the gas pump (12).

7. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 1, characterized in that, The dilution fan (2) generates a large amount of dilution wind and sends it into the heat exchanger (9) through the air feeding pipeline, and the heat exchanger (9) preheats the dilution wind and sends it into the flue (10).

8. The urea hydrolysis and dilution air heating system for flue gas SCR De-NOx according to claim 1, characterized in that, The ammonia gas fan (8) sends ammonia gas into the flue, mixes with hot dilution wind in the flue (10), and finally enters the SCR reactor (1).

Images