Efficient urea hydrolysis boiler SCR denitration system

Abstract

The utility model discloses an efficient urea hydrolysis boiler SCR (Selective Catalytic Reduction) denitration system, which comprises a screw conveyer (7), a dissolving tank (1), a storage tank (2), a hydrolyzer (4), a boiler (5), a desalting water tank (6) and a drain tank (3), and is characterized in that the screw conveyer (7) is connected with the dissolving tank (1) through a pipeline, the boiler (5) and the desalting water tank (6) are respectively connected with the dissolving tank (1) through pipelines, and the drain tank (3) is connected with the dissolving tank (1) through a pipeline. The dissolving tank (1) is provided with a stirrer, the dissolving tank (1) is connected with the storage tank (2) through a pipeline, the boiler (5) and the demineralized water tank (6) are respectively connected with the hydrolyzer (4) through pipelines, and the hydrolyzer (4) outputs ammonia gas and wastewater obtained after reaction out of a system through pipelines. By arranging the monitoring system and the controller, the injection amount and the temperature of the urea solution are accurately controlled, and the conversion rate from urea to ammonia gas can be maximized.

Description

Technical Field

[0001] The utility model relates to the technical field of boiler SCR denitration, in particular to a high-efficiency urea hydrolysis boiler SCR denitration system. Background Art

[0002] Selective catalytic reduction (SCR) technology is widely used to reduce nitrogen oxide (NOx) emissions. SCR uses a catalyst to preferentially react with NOx in the presence of excess oxygen, reducing it to nitrogen and water vapor. Ammonia is widely used as a reducing agent in the SCR process due to its high activity and selectivity, but it carries certain risks. Urea hydrolysis ammonia production technology eliminates the risks of direct handling and storage of ammonia by thermally decomposing or hydrolyzing a urea solution to produce ammonia and carbon dioxide.

[0003] Urea hydrolysis to produce ammonia technology means that urea can be decomposed into ammonia and carbon dioxide under the action of water, but the hydrolysis rate is slow at low temperatures. If the temperature and pressure of urea hydrolysis are strictly controlled, most of the urea can be hydrolyzed into ammonia and carbon dioxide. The chemical reaction formula is: CO(NH2)+H2O=2NH2+CO2.

[0004] The urea hydrolysis system is complex in design, requiring multiple steps and equipment to control the hydrolysis process of the urea solution, resulting in high energy consumption and equipment investment. Furthermore, the urea hydrolysis system needs to specifically adjust the urea hydrolysis reaction rate based on the SCR system's demand for ammonia and control the flow of urea solution entering the hydrolyzer. However, manual operation makes it difficult to respond in a timely manner, resulting in low conversion efficiency. Utility Model Content

[0005] The purpose of the utility model is to provide a high-efficiency urea hydrolysis boiler SCR denitrification system to solve the problems of high energy consumption and low ammonia conversion efficiency raised in the above background technology.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a high-efficiency urea hydrolysis boiler SCR denitrification system, comprising a screw conveyor, a dissolving tank, a storage tank, a hydrolyzer, a boiler, a desalted water tank, and a drain tank, wherein the screw conveyor and the dissolving tank are connected by a pipeline to convey dry urea, the boiler and the desalted water tank are respectively connected to the dissolving tank by pipelines to convey desalted water and steam to the dissolving tank, the dissolving tank is equipped with an agitator to dissolve the dry material, and the dissolving tank is connected to the storage tank by a pipeline to convey the dissolved urea solution; the storage tank and the hydrolyzer are connected by a pipeline to convey the stored urea solution, and the boiler and the desalted water tank are respectively connected to the storage tank by pipelines to convey desalted water and steam to the storage tank;

[0007] The boiler and the desalted water tank are respectively connected to the hydrolyzer through pipelines to transmit desalted water and steam to the hydrolyzer, and the hydrolyzer outputs the ammonia gas and wastewater obtained after the reaction to the system through pipelines;

[0008] Two pipes are connected between the drain tank and the dissolution tank, the storage tank, and the hydrolyzer. The drain tank and the boiler are connected through the pipes. The drain in the dissolution tank, the storage tank, and the hydrolyzer is recovered and separated into steam and drain by a water pump, and the drain is returned to the dissolution tank, the storage tank, and the hydrolyzer for recycling, and the steam is returned to the boiler for reuse.

[0009] Preferably, the temperature in the hydrolyzer needs to be maintained at 130-160°C, and the pressure is controlled at 0.4-0.6MPa. The hydrolyzer is connected to three monitoring devices: a thermometer, a water level monitor, and a pressure gauge, which respectively monitor the temperature, water level and pressure of the hydrolyzer, and transmit the data to the monitoring system. The monitoring system analyzes and determines whether the hydrolyzer environment meets the reaction requirements and whether the water level is within the normal range. After the judgment is completed, a signal is sent to the controller. The storage tank, boiler, desalted water tank, drain tank and the pipeline connected to the hydrolyzer are respectively installed with a liquid inlet valve and a steam valve. The desalted water valve and the valve, the liquid inlet valve and the steam valve are respectively controlled by a liquid inlet controller and a pressure controller. The desalted water valve and the valve are controlled by a temperature controller. The liquid inlet controller, the pressure controller and the temperature controller are all connected to the monitoring system, and the valve state is changed after receiving the signal sent by the monitoring system.

[0010] Preferably, the mass fraction of the urea solution in the solution tank and the storage tank should be 40% to 50%, the dissolving tank is equipped with a monitor 1, the pipelines connecting the boiler and the desalted water tank to the dissolving tank are respectively equipped with a steam valve 1 and a water inlet valve, the steam valve 1 and the water inlet valve are respectively controlled by a valve controller 1 and a water inlet controller, the pipeline connecting the dissolving tank and the storage tank is equipped with a storage valve, the storage valve is controlled by the storage controller, the screw conveyor has a conveying motor, and the conveying motor is connected to the motor controller;

[0011] The monitor is connected to the monitoring system to monitor the solution concentration, water level and temperature of the dissolution tank for analysis and transmit the signal to the controller. If the liquid level in the dissolution tank is lower than the low liquid level, the water inlet valve is opened by the water inlet controller; when the liquid level is higher than the low liquid level, the water inlet valve is closed; if the solution concentration is insufficient, the motor controller controls the feeding; when the concentration meets the requirement, the feeding is stopped; when the concentration meets the requirement and the water level is sufficient, the storage valve is opened by the storage controller.

[0012] Preferably, the storage tank is equipped with a second monitor, and a second steam valve is installed on the pipe connecting the boiler and the storage tank. The second steam valve is controlled by a second valve controller. The second monitor is connected to the monitoring system to monitor the water level and temperature of the storage tank and perform analysis, and transmit the signal to the controller. The storage valve controls the water level, and the steam valve controls the steam entering and the condensed water flowing into the drain tank to keep the temperature in the storage tank constant.

[0013] Compared with the existing technology, the beneficial effects of the present invention are: 1. The present invention accurately controls the injection amount and temperature of the urea solution through the setting of the monitoring system and controller, thereby maximizing the conversion rate of urea to ammonia and ensuring that the entire system is maintained under the conditions required for the reaction. At the same time, the monitoring system can reflect the status of the entire system, making it easier for staff to maintain and improve the system.

[0014] 2. The utility model separates the collected gas and liquid through the drain box, and the obtained condensed water and steam are recycled for reuse, which reduces the external energy demand, reduces the system energy consumption, and achieves greater economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the device of the present utility model.

[0016] Figure 2 This is a schematic diagram of the structure of the utility model.

[0017] In the figure: 1. Dissolution tank; 2. Storage tank; 3. Drain tank; 4. Hydrolyzer; 5. Boiler; 6. Desalted water tank; 7. Screw conveyor. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0019] See also Figure 1 The utility model provides a technical solution: a high-efficiency urea hydrolysis boiler SCR denitrification system, comprising a screw conveyor 7, a dissolving tank 1, a storage tank 2, a hydrolyzer 4, a boiler 5, a desalted water tank 6, and a drain tank 3. The screw conveyor 7 and the dissolving tank 1 are connected by a pipeline to transport urea dry material, so that the speed is controllable and it is convenient to adjust the feed according to subsequent conditions. The boiler 5 and the desalted water tank 6 are respectively connected to the dissolving tank 1 through pipelines to transmit desalted water and steam to the dissolving tank 1. The dissolving tank 1 is equipped with a stirrer to dissolve dry material. The dissolving tank 1 is connected to the storage tank 2 through a pipeline to transmit the dissolved urea solution.

[0020] The storage tank 2 and the hydrolyzer 4 are connected by pipelines to transmit the stored urea solution, and the boiler 5 and the desalted water tank 6 are connected by pipelines to the storage tank 2 to transmit desalted water and steam to the storage tank 2;

[0021] The boiler 5 and the desalted water tank 6 are connected to the hydrolyzer 4 through pipelines to transmit desalted water and steam to the hydrolyzer 4, and the hydrolyzer 4 outputs the ammonia gas and wastewater obtained after the reaction to the system through pipelines;

[0022] There are two pipes connected between the drain tank 3 and the dissolving tank 1, the storage tank 2, and the hydrolyzer 4, which are used for input and output respectively. The drain tank 3 and the boiler 5 are connected by the pipe. The drain in the dissolving tank 1, the storage tank 2, and the hydrolyzer 4 is recovered and separated into steam and drain by a water pump, and the drain is returned to the dissolving tank 1, the storage tank 2, and the hydrolyzer 4 for recycling, and the steam is returned to the boiler 5 for reuse, saving energy consumption.

[0023] See also Figure 2 , the temperature in the hydrolyzer needs to be maintained at 130-160°C, and the pressure is controlled at 0.4-0.6MPa. The hydrolyzer 4 is connected to three monitoring devices: a thermometer, a water level monitor, and a pressure gauge, which respectively monitor the temperature, water level and pressure of the hydrolyzer, and transmit the data to the monitoring system. The monitoring system analyzes and determines whether the hydrolyzer environment meets the reaction requirements and whether the water level is within the normal range. After the judgment is completed, a signal is sent to the controller. The pipelines connecting the storage tank 2, the boiler 5, the desalted water tank 6, the drain tank 3 and the hydrolyzer 4 are respectively equipped with a liquid inlet valve, a steam valve 3, a desalted water valve, and a valve. The liquid inlet valve and the steam valve 3 are controlled by the liquid inlet controller and the pressure controller respectively. The desalted water valve and the valve are controlled by the temperature controller. The liquid inlet controller, the pressure controller, and the temperature controller are all connected to the monitoring system, and the valve state is changed after receiving the signal sent by the monitoring system;

[0024] The mass fraction of urea solution in the solution tank and the storage tank should be 40% to 50%. The dissolving tank 1 is equipped with a monitor 1. The pipelines connecting the boiler 5 and the desalted water tank 6 to the dissolving tank 1 are respectively equipped with a steam valve 1 and a water inlet valve. The steam valve 1 and the water inlet valve are respectively controlled by a valve controller 1 and a water inlet controller. The pipeline connecting the dissolving tank 1 and the storage tank 2 is equipped with a storage valve. The storage valve is controlled by a storage controller. The screw conveyor 7 has a conveying motor, which is connected to a motor controller.

[0025] Monitor 1 is connected to the monitoring system to monitor the solution concentration, water level and temperature of the dissolving tank 1 for analysis and transmit the signal to the controller. If the liquid level of the dissolving tank 1 is lower than the low liquid level, the water inlet valve is opened by the water inlet controller. When the liquid level is higher than the low liquid level, the water inlet valve is closed. If the solution concentration is insufficient, the motor controller controls the feeding. When the concentration meets the requirement, the feeding is stopped. When the concentration meets the requirement and the water level is sufficient, the storage controller opens the storage valve. The system automatically starts the agitator after detecting the pump stop and the water inlet valve closing signal.

[0026] The storage tank 2 is equipped with a second monitor, and a second steam valve is installed on the pipe connecting the boiler 5 and the storage tank 2. The second steam valve is controlled by a second valve controller. The second monitor is connected to the monitoring system to monitor the water level and temperature of the storage tank 2 and analyze them, and transmit the signal to the controller. The storage valve controls the water level to keep the water level constant so as not to affect the ammonia preparation rate. The steam valve controls the steam entering and the condensed water flowing into the drain tank to keep the temperature in the storage tank 2 constant.

[0027] Working principle: When the motor starts, the screw conveyor 7 conveys urea dry material to the dissolving tank 1, and the desalted water tank flows into the desalted water to dissolve the urea dry material. The boiler steam flows in to maintain the temperature to ensure the dissolution efficiency. The monitor is connected to the monitoring system to monitor the solution concentration, water level and temperature of the dissolving tank 1 for analysis and transmit the signal to the controller. If the liquid level of the dissolving tank 1 is lower than the low liquid level, the water inlet valve is opened by the water inlet controller. When the liquid level is higher than the low liquid level, the water inlet valve is closed. After the system detects the pump stop and the water inlet valve closing signal, it automatically starts the agitator. The agitator accelerates the dissolution of the dry material. The solution concentration requirement is 50%. If the solution concentration is insufficient, the motor controller controls the feeding. When the concentration meets the requirement, the feeding is stopped. When the concentration meets the requirement and the water level is sufficient, the storage controller opens the storage valve, and the urea solution is pumped into the storage tank 2 for storage by the water pump, and the steam is blown into the drain tank 3 for recovery; the steam flowing into the storage tank 2 is blown into the drain tank for recovery; the 50% concentration urea solution in the storage tank 2 flows into the hydrolyzer 4 through the water pump, and at a temperature of 13 The decomposition reaction occurs under the conditions of 0-150℃ and pressure of 0.45-0.55MPa, and is converted into carbon dioxide and ammonia. The hydrolyzer 4 is connected to three monitoring devices: a thermometer, a water level monitor, and a pressure gauge, which respectively monitor the temperature, water level and pressure of the hydrolyzer 4, and transmit the data to the monitoring system. The monitoring system analyzes and determines whether the environment of the hydrolyzer 4 meets the reaction requirements and whether the water level is within the normal range. After the judgment is completed, a signal is sent to the controller. The pipelines connecting the storage tank 2, the boiler 5, the desalted water tank 6, the drain tank 3 and the hydrolyzer 4 are respectively equipped with a liquid inlet valve, a steam valve 3, a desalted water valve, and a valve. The liquid inlet valve and the steam valve 3 are controlled by the liquid inlet controller and the pressure controller respectively. The desalted water valve and the valve are controlled by the temperature controller. The liquid inlet controller, the pressure controller, and the temperature controller are all connected to the monitoring system. After receiving the signal sent by the monitoring system, the valve state is changed. After the reaction of the hydrolyzer 4 is completed, the ammonia gas flows out into the subsequent system, the wastewater is recovered, and the steam is extracted into the drain tank 3;

[0028] The steam trap is divided into two types: steam system and gas system. The steam trap is installed at the terminal of the steam-heated pipeline to collect and reuse the condensed water in the steam-heated pipeline. The condensed water is transported to the dissolution tank, storage tank, and hydrolyzer condensate pipeline for temperature control. The steam is recovered by blowing into the boiler and then transported for reuse.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency urea hydrolysis boiler SCR denitrification system, comprising a screw conveyor (7), a dissolution tank (1), a storage tank (2), a hydrolyzer (4), a boiler (5), a desalted water tank (6), and a drain tank (3), characterized in that: The screw conveyor (7) and the dissolving tank (1) are connected via a pipeline to transport urea dry material, the boiler (5) and the desalted water tank (6) are respectively connected to the dissolving tank (1) via pipelines to transmit desalted water and steam to the dissolving tank (1), the dissolving tank (1) is equipped with a stirrer to dissolve the dry material, and the dissolving tank (1) is connected to the storage tank (2) via a pipeline to transmit the dissolved urea solution; The storage tank (2) and the hydrolyzer (4) are connected via a pipeline to transmit the stored urea solution, and the boiler (5) and the desalted water tank (6) are respectively connected to the storage tank (2) via a pipeline to transmit desalted water and steam to the storage tank (2); The boiler (5) and the desalted water tank (6) are respectively connected to the hydrolyzer (4) through pipelines to transmit desalted water and steam to the hydrolyzer (4), and the hydrolyzer (4) outputs ammonia gas and wastewater obtained after the reaction to the system through pipelines; Two pipes are connected between the drain tank (3) and the dissolving tank (1), the storage tank (2), and the hydrolyzer (4). The drain tank (3) and the boiler (5) are connected through the pipes. The drain in the dissolving tank (1), the storage tank (2), and the hydrolyzer (4) is recovered and separated into steam and drain by a water pump, and the drain is returned to the dissolving tank (1), the storage tank (2), and the hydrolyzer (4) for recycling and utilization, and the steam is returned to the boiler (5) for reuse.

2. The high-efficiency urea hydrolysis boiler SCR denitrification system according to claim 1, characterized in that: The temperature in the hydrolyzer needs to be maintained at 130-160°C, and the pressure is controlled at 0.4-0.6MPa. The hydrolyzer (4) is connected to three monitoring devices, namely a thermometer, a water level monitor, and a pressure gauge, which respectively monitor the temperature, water level and pressure of the hydrolyzer and transmit the data to the monitoring system. The monitoring system analyzes and judges whether the hydrolyzer environment meets the reaction requirements and whether the water level is within the normal range. After the judgment is completed, a signal is sent to the controller. The pipelines connecting the storage tank (2), the boiler (5), the desalted water tank (6), the drain tank (3) and the hydrolyzer (4) are respectively installed with a liquid inlet valve, a steam valve 3, a desalted water valve, and a valve. The liquid inlet valve and the steam valve 3 are respectively controlled by a liquid inlet controller and a pressure controller. The desalted water valve and the valve are controlled by a temperature controller. The liquid inlet controller, the pressure controller, and the temperature controller are all connected to the monitoring system. After receiving the signal sent by the monitoring system, the valve state is changed.

3. The high-efficiency urea hydrolysis boiler SCR denitrification system according to claim 1, characterized in that: The mass fraction of the urea solution in the solution tank and the storage tank should be 40% to 50%. The dissolving tank (1) is equipped with a monitor. The pipelines connecting the boiler (5) and the desalted water tank (6) to the dissolving tank (1) are respectively equipped with a steam valve (1) and a water inlet valve. The steam valve (1) and the water inlet valve are respectively controlled by a valve controller (1) and a water inlet controller. The pipeline connecting the dissolving tank (1) and the storage tank (2) is equipped with a storage valve. The storage valve is controlled by a storage controller. The screw conveyor (7) has a conveying motor, and the conveying motor is connected to a motor controller. The monitor is connected to the monitoring system, monitors the solution concentration, water level and temperature of the dissolving tank (1) for analysis, and transmits the signal to the controller. If the liquid level of the dissolving tank (1) is lower than the low liquid level, the water inlet valve is opened by the water inlet controller. When the liquid level is higher than the low liquid level, the water inlet valve is closed. If the solution concentration is insufficient, the motor controller controls the feeding. When the concentration meets the requirement, the feeding is stopped. When the concentration meets the requirement and the water level is sufficient, the storage controller opens the storage valve.

4. The high-efficiency urea hydrolysis boiler SCR denitrification system according to claim 1, characterized in that: The storage tank (2) is equipped with a second monitoring instrument. A second steam valve is installed on the pipe connecting the boiler (5) and the storage tank (2). The second steam valve is controlled by a second valve controller. The second monitoring instrument is connected to the monitoring system to monitor the water level and temperature of the storage tank (2) and analyze them, and transmit the signal to the controller. The storage valve controls the water level, and the steam valve controls the steam entering and the condensed water flowing into the drain tank to keep the temperature in the storage tank (2) constant.

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