Coal gasification ammonia-containing water ammonia recovery tower with on-line cleaning function

Abstract

The present application belongs to the technical field of coal gasification ash water treatment, and particularly relates to an ammonia recovery tower for coal gasification ash water ammonia extraction which can be cleaned online. In the existing coal gasification ash water ammonia extraction process, high ash water hardness and water quality fluctuation can easily lead to the scaling and plugging of the tray 2 of the ammonia recovery tower, which requires shutdown cleaning, affects the continuity of production, and reduces the ammonia recovery efficiency. The present application correspondingly sets online cleaning devices on each layer of trays inside the ammonia recovery tower, and the cleaning devices are integrated in the tray operation area, so that the tray plate surface, screen hole and gas-liquid contact channel can be cleaned and descaled in real time under the normal operating condition of the ammonia recovery tower. The present application can eliminate the scaling and plugging problem caused by high hardness ash water in real time without stopping the equipment and disassembling the tower body, can guarantee the gas-liquid mass transfer efficiency in the tower, can ensure the continuous and stable operation of the ammonia recovery tower, can greatly reduce the equipment operation and maintenance cost and parking loss, and is suitable for the ash water ammonia extraction system of various types of coal slurry gasification processes.

Description

Technical Field

[0001] This invention belongs to the field of coal gasification ash water treatment technology, specifically relating to an ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water. Background Technology

[0002] Coal-water slurry gasification technology is one of the core processes in modern coal chemical industry. During the gasification process, a large amount of coal gasification ash water is generated. This ash water contains high concentrations of free ammonia, ammonium salts, and other ammonia-containing substances. Direct discharge would lead to resource waste and water pollution. Therefore, ammonia recovery towers are commonly used in industry to treat the ash water to remove ammonia, thereby realizing the recovery and resource utilization of ammonia.

[0003] Coal gasification production involves complex operating conditions, resulting in ash water with poor stability, high calcium and magnesium ion content, and high water hardness. Existing ash water pretreatment equipment often suffers from incomplete hardening removal and poor adaptability to fluctuations in operating conditions, leading to excessive hardness in the ash water entering the ammonia recovery tower. During gas-liquid mass transfer and temperature-induced desorption in the ammonia recovery tower, the high-hardness ash water readily precipitates as carbonates and sulfates, forming hard scale that continuously adheres to the tower trays, sieve holes, and gas-liquid channels.

[0004] As equipment operating time increases, scale buildup accumulates on the trays, causing blockage of the tray sieves, reduced gas-liquid contact area, and increased mass transfer resistance. This directly leads to decreased ammonia recovery efficiency, abnormal pressure drop within the tower, and erratic operating conditions. When scale buildup becomes severe, gas-liquid flow within the tower is completely blocked, necessitating a forced shutdown of the equipment. Scale must then be removed through manual disassembly of the tower, high-pressure water washing, or chemical cleaning.

[0005] Existing ammonia recovery towers lack online cleaning capabilities. Shutting down for cleaning not only interrupts the continuous coal chemical production process, causing production line downtime losses, but also presents problems such as long cleaning cycles, large maintenance workload, high labor costs, and easy damage to equipment seals and wear and tear on parts caused by tower disassembly and assembly. These issues severely restrict the stable, efficient, and continuous operation of the coal gasification ash water ammonia extraction system, and are currently a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by solving the technical problems of traditional ammonia recovery towers used for ammonia extraction from coal gasification ash water, which lack online cleaning functions, are prone to scaling and clogging of the tower trays due to high-hardness ash water, require frequent shutdowns for cleaning, have poor production continuity, high operation and maintenance costs, and have unstable ammonia recovery efficiency.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an ammonia recovery tower for coal gasification ash water ammonia extraction that can be cleaned online. It includes a vertical tower body and multiple layers of trays fixedly installed inside the tower body from top to bottom. The tower body has an ammonia gas outlet at the top, an ash water inlet on the side wall, and a treated wastewater outlet at the bottom. The core improvement lies in the integrated installation of an independent online cleaning device on each tray. This online cleaning device is fully adapted to the tray structure and can perform comprehensive cleaning and descaling of the tray surface, sieve holes, and gas-liquid channels under normal continuous operation under load.

[0008] Furthermore, the online cleaning device a includes a water supply component, cleaning pipelines, control valves, a spray component, and an intelligent control module; the cleaning pipelines are laid in a ring along the outer edge of each tray and fixed at a preset position above the tray; multiple high-pressure spray heads are evenly distributed inside the cleaning pipelines, with the spray range fully covering the working surface of the trays; a sealing component is installed at the point where the cleaning pipelines exit the tower body to ensure the airtightness of the tower body; the control valves are located at the water inlet of each cleaning pipeline to achieve independent on / off control of each layer; the water supply component provides a stable pressure clean water source, suitable for the high temperature and high pressure operating environment inside the tower.

[0009] Furthermore, the online cleaning device b includes a water supply component, cleaning pipelines, control valves, a spray component, and an intelligent control module; the spray component is located in the center of the tower tray, the cleaning pipelines are connected to the spray pipelines of the spray component, the spray pipelines are located in the space above the tower tray via support pipelines, and multiple high-pressure spray heads are evenly distributed on the lower side of the spray pipelines, with the spray range fully covering the working surface of the tower tray; a sealing component is installed at the position where the cleaning pipelines exit the tower body to ensure the airtightness of the tower body; the control valves are located at the water inlet end of the cleaning pipelines of each layer to realize independent on / off control of each layer; the water supply component provides a stable pressure cleaning water source, which is suitable for the high temperature and high pressure operating environment inside the tower.

[0010] Furthermore, the spray pipe of the online cleaning device b is rotatable about the support pipe.

[0011] Furthermore, the high-pressure spray head of the spray assembly sprays at an angle that covers the entire surface of the tray and the tray sieve area.

[0012] Furthermore, the online cleaning device is sealed to the tower body, and a sealing component is installed where the cleaning pipeline passes through the tower body.

[0013] Furthermore, the water supply component is an industrial softened water supply system or a grey water treatment purification system.

[0014] Furthermore, the online cleaning device is also equipped with an intelligent control module, which can collect the scaling data of the trays in real time, automatically trigger the cleaning program according to the scaling thickness, and can also be set to perform timed online cleaning, so as to realize intelligent and unmanned descaling operation, and the cleaning operation and ammonia extraction operation are carried out simultaneously without interference.

[0015] Furthermore, the intelligent control module includes a timing control module and a scale detection module. The scale detection module is installed on the surface of the tray to monitor the scale thickness of the tray in real time. The timing control module is electrically connected to the control valve and the scale detection module to realize automatic timed cleaning and on-demand intelligent cleaning.

[0016] Furthermore, the online cleaning device for the multi-layer trays is independently controlled, enabling individual cleaning of a single layer or simultaneous cleaning of multiple layers.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention achieves online cleaning without downtime: By installing a dedicated online cleaning device on the trays inside the ammonia recovery tower, the invention can complete the descaling of the trays under the premise of normal operation of the ammonia recovery tower without stopping the machine, depressurizing, or interrupting production. This completely solves the drawback of traditional equipment requiring downtime for cleaning, ensures the continuous and stable operation of the coal gasification production line, and significantly reduces losses due to downtime.

[0018] 2. Long-term guarantee of ammonia recovery efficiency: This invention can remove hard scale precipitated on the trays in real time and on a regular basis, avoiding sieve blockage and obstruction of gas-liquid mass transfer channels, continuously ensuring the gas-liquid contact area and mass transfer efficiency of the trays, stabilizing the ammonia recovery capacity and recovery purity of the ammonia recovery tower, and adapting to the working conditions of coal gasification ash water treatment with high hardness and large water quality fluctuations.

[0019] 3. Significantly reduced operation and maintenance costs: This invention eliminates the need for manual disassembly and cleaning, reducing the workload of manual operation and maintenance, avoiding seal damage and component wear caused by disassembly and assembly, extending the service life of the equipment, and reducing equipment inspection and maintenance costs.

[0020] 4. Strong intelligent adaptability: This invention supports multiple modes such as manual cleaning, timed automatic cleaning, and intelligent scaling-triggered cleaning. It features independent layer control and can perform targeted cleaning based on the scaling conditions of different trays. The cleaning is highly accurate, consumes less water, and is energy-efficient. Attached Figure Description

[0021] Figure 1 A three-dimensional structural diagram of the online cleaning device a of the ammonia recovery tower of the present invention, installed inside the tower; Figure 2 A three-dimensional structural diagram of the online cleaning device b of the ammonia recovery tower of the present invention, which is set in the center of the tower tray; In the diagram: 1-Tower body; 2-Tower tray; 3-Cleaning pipeline; 4-High-pressure spray head; 5-Spray pipeline; 6-Support pipeline. Detailed Implementation

[0022] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention. Example 1

[0023] Reference Figure 1 This embodiment provides an ammonia recovery tower for ammonia extraction from coal gasification ash water that can be cleaned online. It includes a tower body 1, sieve trays 2, an ash water inlet, an ammonia outlet, a wastewater outlet, internal support components, and an online cleaning device a. The tower body 1 is a vertical, sealed pressure tank. The trays 2 are horizontally layered and fixed inside the tower body 1 from top to bottom. The spacing between adjacent trays 2 is uniformly set to 800mm, suitable for conventional ammonia extraction from coal gasification ash water.

[0024] In this embodiment, each tray 2 is equipped with a separate online cleaning device a. Each online cleaning device a includes a ring cleaning pipeline 3, a high-pressure spray head 4, a control valve, a softened water supply pump, a sealing flange, an intelligent control terminal, and a scale sensor.

[0025] The annular cleaning pipeline 3 is made of 304 stainless steel and is fixed around the outer edge of the tray 2, 150mm above the tray surface, to avoid interfering with gas-liquid mass transfer within the tower. High-pressure spray heads 4 are evenly spaced inside the annular cleaning pipeline 3, with adjustable spray angles. The overall spray range completely covers all sieve holes and the tray surface area, eliminating blind spots. The cleaning pipeline 3 exits the tower body 1 using a flanged seal, suitable for high-temperature, slightly positive-pressure conditions within the tower, preventing ammonia leakage.

[0026] Each cleaning pipeline 3 has an independent control valve installed at its inlet end, enabling independent control of the cleaning operation of a single-layer tray 2. It can start cleaning of any layer individually or multiple layers can be cleaned simultaneously. The water supply components use pre-treated softened water from the plant.

[0027] Scale sensors are attached to the center of each tray 2 to monitor the scale thickness on the tray 2 surface in real time, and the monitoring data is transmitted to the intelligent control terminal in real time. The intelligent control terminal presets a scale threshold. When the scale thickness reaches 0.2mm, it automatically triggers the cleaning program of the corresponding tray 2, opens the control valve and water supply pump, and uses high-pressure spray water to flush the tray 2 surface and screen holes, washing away uncured scale and loose scale in real time. The flushed wastewater is discharged normally down the tower with the wastewater.

[0028] Meanwhile, the control terminal is equipped with a timed cleaning mode, which can be set to perform online cleaning 1-2 times daily, with each cleaning session lasting 3-5 minutes. This achieves preventative descaling, preventing scale buildup and solidification at the source. Throughout the cleaning process, the ammonia recovery tower continues to receive ash water and recover ammonia gas normally, with no fluctuations in production conditions and no need for any shutdown operations. Example 2

[0029] Reference Figure 2This embodiment provides an ammonia recovery tower for ammonia extraction from coal gasification ash water that can be cleaned online. It includes a tower body 1, sieve trays 2, an ash water inlet, an ammonia outlet, a wastewater outlet, internal support components, and an online cleaning device b. The tower body 1 is a vertical, sealed pressure tank. The trays 2 are horizontally layered and fixed inside the tower body 1 from top to bottom. The spacing between adjacent trays 2 is uniformly set to 600mm, suitable for conventional ammonia extraction from coal gasification ash water.

[0030] In this embodiment, each tray 2 is equipped with a separate online cleaning device b. Each online cleaning device b mainly consists of a water supply component, a cleaning pipeline 3, a control valve, a spray component, and an intelligent control module. The spray component is located in the center of the tray 2. The cleaning pipeline 3 is connected to the spray pipeline 5 of the spray component. The spray pipeline 5 is located in the space above the tray 2 via a support pipeline 6. Multiple high-pressure spray heads 4 are evenly distributed on the lower side of the spray pipeline 5, and the spray range fully covers the working surface of the tray 2. A sealing component is installed at the position where the cleaning pipeline 3 exits the tower body 1 to ensure the airtightness of the tower body 1. The control valve is located at the water inlet of each layer's cleaning pipeline 3 to achieve independent on / off control of each layer. The water supply component provides a stable pressure cleaning water source, which is adapted to the temperature and pressure environment of the tower.

[0031] The cleaning pipeline 3, spray assembly, and support pipeline 6 are made of 304 stainless steel. The spray pipeline 5 of the spray assembly is 200mm above the surface of the tray 2 to avoid interfering with gas-liquid mass transfer within the tower. Under the reaction force of the high-pressure spray head 4, the cleaning pipeline 3 can rotate around the support pipeline 6, and the rotational spray range completely covers all sieve holes and the surface area of ​​the tray 2, with no blind spots. The cleaning pipeline 3 is sealed with a flange at the point where it exits the tower body 1, adapting to the temperature and pressure conditions inside the tower and preventing ammonia leakage.

[0032] Each cleaning pipeline 3 has an independent control valve installed at its inlet, enabling independent control of the cleaning operation of a single-layer tray 2. It can start cleaning of any layer individually or multiple layers can be cleaned simultaneously. The water supply component uses hot water from the bottom of the ammonia recovery tower.

[0033] Scale sensors are attached to the center of each tray 2 to monitor the scale thickness on the tray 2 surface in real time, and the monitoring data is transmitted to the intelligent control terminal in real time. The intelligent control terminal presets a scale threshold. When the scale thickness reaches 0.2mm, it automatically triggers the cleaning program of the corresponding tray 2, opens the control valve and water supply pump, and uses high-pressure spray water to flush the tray 2 surface and screen holes, washing away uncured scale and loose scale in real time. The flushed wastewater is discharged normally down the tower with the wastewater.

[0034] Meanwhile, the control terminal is equipped with a timed cleaning mode, which can be set to perform online cleaning 1-2 times daily, with each cleaning session lasting 3-5 minutes. This achieves preventative descaling, preventing scale buildup and solidification at the source. Throughout the cleaning process, the ammonia recovery tower continues to receive ash water and recover ammonia gas normally, with no fluctuations in production conditions and no need for any shutdown operations.

[0035] Another embodiment differs from Embodiment 1 in that, for extreme conditions with large fluctuations in water quality and persistently high hardness in greywater, the online cleaning device is equipped with a micro-chemical cleaning aid dosing component. This allows for the addition of trace amounts of environmentally friendly descaling agents to the cleaning water, enhancing the removal effect on lightly solidified hard scale. Furthermore, the amount of agent added is controllable and will not affect the ammonia extraction quality of the greywater or subsequent wastewater treatment processes. The remaining structure and operation are consistent with Embodiment 1, enabling 24 / 7 uninterrupted online descaling and adapting to high-load, high-hardness greywater continuous treatment conditions.

[0036] The working principle of this invention: By installing a dedicated online cleaning device on tray 2 of the ammonia recovery tower, this invention can complete the descaling of tray 2 under the premise of normal operation of the ammonia recovery tower, without stopping the machine, without depressurization, and without interrupting production. This completely solves the drawback of traditional equipment requiring shutdown for cleaning, ensures the continuous and stable operation of the coal gasification production line, and significantly reduces the losses caused by downtime. Compared with traditional ammonia recovery towers, it greatly reduces the failure rate of scaling and blockage, significantly reduces equipment maintenance labor costs and downtime loss costs, and has significant overall economic benefits.

[0037] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water, comprising a tower body, multiple trays, a feed inlet, a gas outlet, and a liquid outlet, wherein the multiple trays are horizontally fixed inside the tower body from top to bottom, characterized in that: Each tray is equipped with an online cleaning device, which is adapted to the tray structure and can perform online descaling and cleaning of the trays without stopping the operation while the ammonia recovery tower is running normally and continuously.

2. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 1, characterized in that: The online cleaning device a includes a cleaning pipeline, a spray assembly, a control valve, a water supply assembly, and an intelligent control module. The cleaning pipeline is arranged around the edge of the tray. The spray assembly is evenly installed on the side of the cleaning pipeline facing the tray. The control valve is installed at the water inlet of the cleaning pipeline. The water supply assembly is connected to the cleaning pipeline to provide cleaning water to the spray assembly.

3. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 1, characterized in that: The online cleaning device b includes cleaning pipelines, control valves, a water supply assembly, and an intelligent control module. The spray assembly is located in the center of the tower tray, and the cleaning pipelines are connected to the spray pipelines of the spray assembly. The spray pipelines are located in the space above the tower tray via support pipelines. Multiple high-pressure spray heads are evenly distributed on the lower side of the spray pipelines, and the spray range fully covers the working surface of the tower tray. A sealing assembly is installed at the point where the cleaning pipelines exit the tower body to ensure the airtightness of the tower body. The control valves are located at the water inlet of each layer of the cleaning pipelines to achieve independent on / off control of each layer. The water supply assembly provides a stable pressure cleaning water source, which is suitable for the high temperature and high pressure operating environment inside the tower.

4. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 3, characterized in that: The spray pipe of the online cleaning device b is rotatable about the support pipe.

5. An ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 2 or 3, characterized in that: The high-pressure spray head of the spray assembly sprays at an angle that covers the entire surface of the tray and the area of ​​the tray sieve holes.

6. An ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to any one of claims 1-3, characterized in that: The water supply components are industrial softened water supply systems or grey water treatment purification systems.

7. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 1, characterized in that: The online cleaning device also includes a timed control module and a scale detection module. The scale detection module is installed on the surface of the tray to monitor the scale thickness of the tray in real time. The timed control module is electrically connected to the control valve and the scale detection module to realize automatic timed cleaning and on-demand intelligent cleaning.

8. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 1, characterized in that: The online cleaning device is sealed to the tower body, and a sealing component is installed where the cleaning pipeline passes through the tower body.

9. The ammonia recovery tower for online cleaning of ammonia extraction from coal gasification ash water according to claim 1, characterized in that: The online cleaning device for the multi-layer trays is independently controlled, enabling individual cleaning of a single layer or simultaneous cleaning of multiple layers.

Images