Improved denitration system for thermal power plant
By adding sub-silo and preheating device for urea hydrolysis catalyst in the denitrification system of the thermal power plant, the problem of difficult nitrogen oxide emissions in the thermal power plant is solved when the thermal power plant is mixed with inferior coal, and the ammonia production of the hydrolysis device and the stable operation of the system are achieved.
Patent Information
- Application Number
- CN202421459037.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-25
- Publication Date
- 2025-04-15
- Estimated Expiration
- 2034-06-25
AI Technical Summary
When thermal power plants are mixed with inferior coal, the nitrogen oxides generated by boiler combustion have increased dramatically. The existing denitrification systems are prone to overtemperature and overpressure under high ammonia production conditions, and the hydrolysis device design cannot meet the demand for inferior coal, resulting in the problem of system transformation and adding hydrolysis devices.
An improved denitrification system for thermal power plants was designed, and a sub-silo for urea hydrolysis catalyst was added. A preheating device was set up on the infusion pipeline to form a mixed solution by stirring urea, urea hydrolysis catalyst and water, and hydrolyzing in the hydrolysis device to produce ammonia for denitrification, while preheating the mixed solution to avoid overtemperature of the hydrolysis device.
Under the original design pressure and temperature, the ammonia production of the hydrolysis device was increased by nearly 50%, avoiding the overtemperature of the hydrolysis device, reducing the transformation project volume, and meeting the denitrification needs of thermal power plants under the conditions of burning inferior coal.
Smart Images
Figure CN222752942U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of denitration, in particular to an improved denitration system of a thermal power plant. Background Art
[0002] In recent years, thermal power plants have been affected by the coal market and have been burning a large amount of low-quality coal. In this environment, the nitrogen oxides produced by boiler combustion have increased dramatically, and the environmental indicator NOx is very difficult to control. The hydrolyzer of the denitrification system frequently overheats and overpressures due to excessive ammonia injection. The output of the hydrolyzer is designed according to the designed coal type, which is currently unable to meet the unit's demand for burning low-quality coal, and is facing the problem of system transformation and adding hydrolyzers. Summary of the invention
[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the utility model provides an improved denitration system for a thermal power plant, aiming to increase the ammonia production of a hydrolyzer.
[0004] Technical solution: To achieve the above-mentioned purpose, the utility model provides an improved denitration system for a thermal power plant, comprising a main silo, an auxiliary silo, and a dissolving tank, a mixing pump, a liquid storage tank, a delivery pump and a hydrolyzer connected in sequence through a liquid infusion pipeline; urea is stored in the main silo, and a urea hydrolysis catalyst is stored in the auxiliary silo, and the main silo and the auxiliary silo can add urea and urea hydrolysis catalyst into the dissolving tank; an agitator is provided in the dissolving tank, and the agitator can stir urea, urea hydrolysis catalyst and water into a mixed solution; the mixed solution in the dissolving tank is transported to the liquid storage tank by the mixing pump for storage, and the mixed solution in the liquid storage tank is transported to the hydrolyzer by the delivery pump for hydrolysis to produce ammonia for denitration.
[0005] Furthermore, a preheating device is provided on the liquid delivery pipeline between the delivery pump and the hydrolyzer, so that the mixed solution in the liquid storage tank is preheated before entering the hydrolyzer.
[0006] Furthermore, the preheating device comprises a heating ring sleeve mounted outside the infusion pipeline, wherein a liquid flow cavity is provided in the heating ring sleeve, and a high-temperature liquid flows in the liquid flow cavity to preheat the mixed solution in the infusion pipeline.
[0007] Furthermore, the preheating device includes a plurality of heating rings, which are arranged in sequence on the infusion pipeline, and the temperature of the high-temperature liquid in each heating ring gradually increases along the liquid flow direction in the infusion pipeline.
[0008] Furthermore, the main material bin and the auxiliary material bin are both arranged above the dissolving tank, the main discharge pipe below the main material bin is opposite to the feed port of the dissolving tank, and an auxiliary discharge pipe is arranged below the auxiliary material bin, and the auxiliary discharge pipe is connected to the main discharge pipe.
[0009] Furthermore, both the main discharge pipe and the auxiliary discharge pipe are provided with electromagnetic control valves.
[0010] Beneficial effects: The improved denitration system for thermal power plants of the utility model has the following beneficial effects:
[0011] 1) An auxiliary silo for storing urea hydrolysis catalyst is added. During the operation of the denitrification system, urea hydrolysis catalyst can be added while preparing urea solution and pumped to the hydrolyzer through the infusion pipeline, which can increase the ammonia production of the hydrolyzer at the original design pressure and temperature;
[0012] 2) A heating ring is provided on the infusion pipeline between the delivery pump and the hydrolyzer, which can preheat the mixed solution entering the hydrolyzer, so that the hydrolyzer is not prone to overheating. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Attached Figure 1 It is a schematic diagram of the denitration system of the utility model. DETAILED DESCRIPTION
[0014] The utility model is further described below in conjunction with the accompanying drawings.
[0015] As attached Figure 1 The improved denitration system of a thermal power plant comprises a main silo 1, an auxiliary silo 2, and a dissolving tank 4, a mixing pump 5, a liquid storage tank 6, a delivery pump 7 and a hydrolyzer 8 connected in sequence through a liquid infusion pipeline 3. Urea is stored in the main silo 1, and a urea hydrolysis catalyst is stored in the auxiliary silo 2. The main silo 1 and the auxiliary silo 2 can add urea and urea hydrolysis catalyst to the dissolving tank 4. A stirrer 9 is provided in the dissolving tank 4, and the stirrer 9 can stir urea, urea hydrolysis catalyst and water into a mixed solution. The stirrer 9 comprises a stirring rod, and a stirring blade is provided at one end of the stirring rod. The other end of the stirring rod is connected to a motor, and the motor drives the stirring rod and the stirring blade to stir the urea, urea hydrolysis catalyst and water in the dissolving tank 4. In practical applications, the added water is usually 50 degrees.
[0016] The mixed solution obtained by stirring in the dissolving tank 4 is sent to the liquid storage tank 6 by the mixing pump 5 for storage. When the hydrolyzer 8 is working, the mixed solution in the liquid storage tank 6 is sent to the hydrolyzer 8 by the delivery pump 7, and the urea component in the mixed solution undergoes a hydrolysis reaction in the hydrolyzer 8 to produce ammonia, which reacts with nitrogen oxides produced by boiler combustion to achieve denitration.
[0017] In practical applications, the urea hydrolysis catalyst is a composite catalyst which uses high-purity phosphate as a carrier and is configured with aluminum oxide, titanium dioxide and a small amount of nickel-vanadium compounds in different proportions. Due to the addition of the auxiliary silo 2, the catalyst can be additionally added during the preparation of the urea solution, thereby increasing the ammonia production of the hydrolyzer 8 by nearly 50% at the original design pressure and temperature, so that the entire denitrification system does not need to add an additional hydrolyzer 8, and the amount of modification work is small.
[0018] A preheating device is provided on the liquid delivery pipeline 3 between the delivery pump 7 and the hydrolyzer 8, so that the mixed solution in the liquid storage tank 6 is preheated before entering the hydrolyzer 8. Since the mixed solution is preheated before entering the hydrolyzer 8, the heat required to be provided by the hydrolyzer 8 is reduced, which can effectively avoid the overheating phenomenon of the hydrolyzer 8.
[0019] The preheating device includes a heating ring 10 sleeved on the outside of the infusion pipeline 3, and a liquid flow cavity is provided in the heating ring 10, and a liquid inlet and a liquid outlet are provided on the liquid flow cavity. The high-temperature liquid flows in the liquid flow cavity through the liquid inlet and the liquid outlet to preheat the mixed solution in the infusion pipeline 3. The high-temperature liquid can be hot water. The preheating device includes a plurality of heating rings 10, and the plurality of heating rings 10 are arranged in sequence on the infusion pipeline 3, and along the liquid flow direction in the infusion pipeline 3, the temperature of the high-temperature liquid in each of the heating rings 10 gradually increases, and accordingly, the mixed solution is gradually preheated and heated up in the process of passing through each heating ring 10.
[0020] The main silo 1 and the auxiliary silo 2 are both arranged above the dissolving tank 4, the main discharge pipe 11 below the main silo 1 is opposite to the feed port 13 of the dissolving tank 4, and an auxiliary discharge pipe 12 is arranged below the auxiliary silo 2, and the auxiliary discharge pipe 12 is connected to the main discharge pipe 11. The urea hydrolysis catalyst can be discharged from the auxiliary discharge pipe 12 of the auxiliary silo 2, enter the main discharge pipe 11, and then enter the dissolving tank 4 from the main discharge pipe 11. The main discharge pipe 11 and the auxiliary discharge pipe 12 are both provided with an electromagnetic control valve 14, which can control the opening and closing of the main discharge pipe 11 and the auxiliary discharge pipe 12, thereby controlling the discharge of the main silo 1 and the auxiliary silo 2.
[0021] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. An improved denitration system for a thermal power plant, characterized in that: The invention comprises a main material bin (1), an auxiliary material bin (2), and a dissolving tank (4), a mixing pump (5), a liquid storage tank (6), a delivery pump (7) and a hydrolyzer (8) which are sequentially connected via a liquid delivery pipeline (3); urea is stored in the main material bin (1), a urea hydrolysis catalyst is stored in the auxiliary material bin (2), and the main material bin (1) and the auxiliary material bin (2) can add urea and the urea hydrolysis catalyst into the dissolving tank (4); a stirrer (9) is arranged in the dissolving tank (4), and the stirrer (9) can stir urea, the urea hydrolysis catalyst and water into a mixed solution; the mixed solution in the dissolving tank (4) is delivered to the liquid storage tank (6) by the mixing pump (5) for storage, and the mixed solution in the liquid storage tank (6) is delivered to the hydrolyzer (8) by the delivery pump (7) for hydrolysis to generate ammonia gas for denitration.
2. The improved denitration system for thermal power plants according to claim 1, characterized in that: A preheating device is provided on the liquid delivery pipeline (3) between the delivery pump (7) and the hydrolyzer (8), so that the mixed solution in the liquid storage tank (6) is preheated before entering the hydrolyzer (8).
3. The improved denitration system for thermal power plants according to claim 2, characterized in that: The preheating device comprises a heating ring (10) sleeved outside the infusion pipeline (3), wherein a liquid flow cavity is provided in the heating ring (10), and a high-temperature liquid flows in the liquid flow cavity to preheat the mixed solution in the infusion pipeline (3).
4. The improved denitration system for thermal power plants according to claim 3, characterized in that: The preheating device comprises a plurality of heating ring sleeves (10), which are arranged in sequence on the infusion pipeline (3), and the temperature of the high-temperature liquid in each of the heating ring sleeves (10) gradually increases along the liquid flow direction in the infusion pipeline (3).
5. The improved denitration system for thermal power plants according to claim 1, characterized in that: The main material bin (1) and the auxiliary material bin (2) are both arranged above the dissolving tank (4); a main discharge pipe (11) below the main material bin (1) is opposite to a feed port (13) of the dissolving tank (4); an auxiliary discharge pipe (12) is arranged below the auxiliary material bin (2); and the auxiliary discharge pipe (12) is connected to the main discharge pipe (11).
6. The improved denitration system for thermal power plants according to claim 5, characterized in that: The main discharge pipe (11) and the auxiliary discharge pipe (12) are both provided with electromagnetic control valves (14).