Online cleaning device for heat exchanger in coal chemical synthesis gas system

Abstract

The utility model relates to the technical field of coal chemical synthesis gas systems, in particular to a heat exchanger on-line cleaning device in a coal chemical synthesis gas system, which comprises a shell-and-tube heat exchanger, and a crude synthesis gas inlet pipe and a crude synthesis gas outlet pipe are respectively connected with a tube pass inlet and a tube pass outlet of the shell-and-tube heat exchanger. The shell pass inlet and outlet are respectively connected with a water inlet pipe and a water outlet pipe; the inlet and outlet of the shell pass are connected with a circulating cleaning pipe, and the circulating cleaning pipe is connected with a chemical pool, a circulating pump I and a cooling device for cooling liquid in the circulating cleaning pipe; valves are arranged on the water inlet pipe, the water outlet pipe and the circulating cleaning pipe; the medicament tank is connected with a circulating filter pipe, the circulating filter pipe is connected with a filter device and a circulating pump II, and the circulating filter pipe is provided with a valve; the on-line cleaning device realizes on-line cleaning of the heat exchanger.

Description

Technical Field

[0001] This utility model relates to the technical field of coal chemical synthesis gas systems, specifically an online cleaning device for heat exchangers in coal chemical synthesis gas systems. Background Technology

[0002] In a coal chemical syngas system, coal is first gasified to produce crude syngas. After heat exchange in equipment such as a waste heat boiler, the crude syngas is cooled by a heat exchanger and an ammonia chiller. Finally, acidic gases in the crude syngas are removed through a low-temperature methanol washing process. During long-term operation, scale easily forms on the surface of heat exchangers due to the high temperature of the process medium and the quality of the circulating water, which reduces the heat transfer efficiency of the heat exchangers and increases energy consumption, thus requiring cleaning. Traditional heat exchanger cleaning methods are mostly offline cleaning, which requires shutting down the equipment and disassembling the heat exchangers. This not only consumes a lot of manpower, material resources and time, but also requires the production system to be shut down during the cleaning process. The shutdown cost of large-scale chemical plants with continuous production is high, and it may also cause safety and environmental impacts. Utility Model Content

[0003] The main objective of this invention is to provide an online cleaning device for heat exchangers in a coal chemical syngas system, in order to solve the problem that the production system needs to be shut down during the heat exchanger cleaning process in the prior art, which may cause safety and environmental impacts.

[0004] To achieve the above objectives, this utility model provides an online cleaning device for heat exchangers in a coal chemical syngas system, comprising a shell-and-tube heat exchanger. The tube side inlet and outlet of the shell-and-tube heat exchanger are respectively connected to a crude syngas inlet pipe and a crude syngas outlet pipe, and the shell side inlet and outlet are respectively connected to a water inlet pipe and a water outlet pipe. A circulating cleaning pipe is connected to the shell side inlet and outlet, and the circulating cleaning pipe is connected to a reagent tank, a circulating pump, and a cooling device for cooling the liquid inside the circulating cleaning pipe. Valves are provided on the water inlet pipe, the water outlet pipe, and the circulating cleaning pipe. A circulating filter pipe is connected to the reagent tank, and a filter device and a circulating pump are connected to the circulating filter pipe, which is also equipped with valves.

[0005] Furthermore, the cooling device includes a cooling heat exchanger connected to the circulating cleaning pipe and a chiller unit connected to the cooling heat exchanger via a pipe.

[0006] Furthermore, an online pH monitor is connected to the circulating filter tube to monitor the pH value of the liquid inside the circulating filter tube.

[0007] Furthermore, a temperature sensor for monitoring the temperature inside the circulating cleaning pipe is connected to the circulating cleaning pipe. The temperature sensor is electrically connected to a PID temperature controller, which is electrically connected to the cooling device.

[0008] This invention enables online cleaning of heat exchangers in coal chemical syngas systems without requiring shutdown, thus avoiding adverse effects on safety and environmental protection.

[0009] This invention, by setting up a circulating filter pipe and a filter device, can filter the cleaning agent without affecting the circulating cleaning pipe. As more and more impurities are filtered, the filter device will affect the flow rate of the liquid in the circulating filter pipe, but it will not affect the flow rate of the liquid in the circulating cleaning pipe. After the filter device has been used for a period of time, the valve on the circulating filter pipe needs to be closed to discharge the impurities in the filter device, which will not affect the continuous operation of the circulating cleaning pipe. Attached Figure Description

[0010] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0011] Figure 1 This is a schematic diagram of the online cleaning device for heat exchangers in the coal chemical syngas system in the embodiment.

[0012] In the diagram: 1. Shell-and-tube heat exchanger; 2. Crude syngas inlet pipe; 3. Crude syngas outlet pipe; 4. Water inlet pipe; 5. Water outlet pipe; 6. Circulating cleaning pipe; 7. Chemical tank; 8. Circulating pump one; 9. Cooling device; 901. Cooling heat exchanger; 902. Chiller unit; 10. Circulating filter pipe; 11. Filter device; 12. Circulating pump two; 13. Temperature sensor; 14. pH monitor; 15. Automatic dosing device. Detailed Implementation

[0013] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0014] Example of an online cleaning device for heat exchangers in a coal chemical syngas system

[0015] like Figure 1As shown, an online cleaning device for a heat exchanger in a coal chemical syngas system includes a shell-and-tube heat exchanger 1. The inlet and outlet of the shell-and-tube heat exchanger 1 are connected to a crude syngas inlet pipe 2 and a crude syngas outlet pipe 3, respectively, while the inlet and outlet of the shell side are connected to a water inlet pipe 4 and a water outlet pipe 5, respectively. A circulating cleaning pipe 6 is connected to the shell side inlet and outlet. A reagent tank 7, a circulating pump 8, and a cooling device 9 for cooling the liquid inside the circulating cleaning pipe 6 are connected to the circulating cleaning pipe 6. Valves are installed on the water inlet pipe 4, the water outlet pipe 5, and the circulating cleaning pipe 6. A circulating filter pipe 10 is connected to the reagent tank 7. A filter device 11 and a circulating pump 12 are connected to the circulating filter pipe 10. The filter device 11 can be a Y-type filter or a basket filter. Valves are installed on the circulating filter pipe 10. An automatic dosing device 15 is connected to the reagent tank 7 via a pipeline.

[0016] The cooling device 9 includes a cooling heat exchanger 901 connected to the circulating cleaning pipe 6 and a chiller unit 902 connected to the cooling heat exchanger 901 via a pipe.

[0017] An online pH monitor 14 is connected to the circulating filter tube 10 to monitor the pH value of the liquid inside the circulating filter tube 10.

[0018] A temperature sensor 13 for monitoring the temperature inside the circulating cleaning pipe 6 is connected to the circulating cleaning pipe 6. The temperature sensor 13 is electrically connected to a PID temperature controller, which is electrically connected to the chiller unit 902.

[0019] Example of an online cleaning method for heat exchangers in a coal chemical syngas system

[0020] A method for online cleaning of heat exchangers in a coal chemical syngas system, using the aforementioned online cleaning device for heat exchangers in a coal chemical syngas system, includes the following steps:

[0021] S1. The crude syngas from coal chemical industry at a temperature of 70-75℃ passes through the tube side of shell-and-tube heat exchanger 1, and the cooling water enters the shell side of shell-and-tube heat exchanger 1 through the inlet pipe 4 and is discharged through the outlet pipe 5.

[0022] S2. Prepare a trisodium phosphate aqueous solution with a pH value of 13-14 and add it to reagent tank 7;

[0023] S3. Close the valves on the inlet pipe 4 and outlet pipe 5, open the valve on the circulating cleaning pipe 6, and pass the trisodium phosphate aqueous solution in the reagent tank 7 into the shell side of the shell-and-tube heat exchanger 1 for cleaning, and circulate the trisodium phosphate aqueous solution along the circulating cleaning pipe 6; adjust the temperature of the trisodium phosphate aqueous solution by the cooling device 9, and after multiple cycles, reduce the temperature of the trisodium phosphate aqueous solution before entering the shell-and-tube heat exchanger 1 to 30-35℃; the temperature of the trisodium phosphate aqueous solution when it exits the shell-and-tube heat exchanger 1 is 68-72℃; the temperature of the crude syngas from coal chemical industry when it exits the shell-and-tube heat exchanger 1 is 35-40℃; the cleaning time of the cleaning solution lasts for 24-48 hours;

[0024] The pH of the liquid in the circulating filter tube 10 is monitored using an online pH monitor 14. When the pH value exceeds the set value, trisodium phosphate aqueous solution is added to the reagent tank 7 in a timely manner to adjust the pH value to the set value.

[0025] When the temperature sensor 13 detects that the liquid temperature in the circulating cleaning pipe 6 exceeds the set value, it sends a signal to the PID temperature controller. The PID temperature controller controls the chiller unit 902 to adjust the operating parameters so that the liquid temperature in the circulating cleaning pipe 6 is maintained at the set value.

[0026] S4. After cleaning is complete, close the valve on the circulating cleaning pipe 6 and open the valves on the inlet pipe 4 and the outlet pipe 5.

[0027] This invention enables online cleaning of heat exchangers in coal chemical syngas systems without requiring shutdown, thus avoiding adverse effects on safety and environmental protection.

[0028] This invention, by setting up a circulating filter pipe and a filter device, can filter the cleaning agent without affecting the circulating cleaning pipe. As more and more impurities are filtered, the filter device will affect the flow rate of the liquid in the circulating filter pipe, but it will not affect the flow rate of the liquid in the circulating cleaning pipe. After the filter device has been used for a period of time, the valve on the circulating filter pipe needs to be closed to discharge the impurities in the filter device, which will not affect the continuous operation of the circulating cleaning pipe.

[0029] This invention uses a trisodium phosphate aqueous solution as the cleaning agent, controlling its temperature to be reduced to 30-35°C before entering the shell-and-tube heat exchanger. This allows the trisodium phosphate aqueous solution to act as both a cleaning agent and a substitute for cooling water in the coal chemical process for heat exchange and cooling of the crude syngas, thus achieving online cleaning of the heat exchanger. While the trisodium phosphate aqueous solution is at a low temperature before entering the shell-and-tube heat exchanger, its temperature rises after heat exchange within the exchanger, exiting at 68-72°C. This temperature ensures optimal descaling, allowing the active components of trisodium phosphate to react more effectively with the minerals in the scale, resulting in more thorough scale removal. The invention avoids excessively high or low temperatures. High temperatures cause partial decomposition, reducing the solution's alkalinity and cleaning power, and corroding the heat exchanger. Low temperatures reduce solubility and decrease cleaning power.

[0030] This invention controls the pH value of the trisodium phosphate aqueous solution, thereby controlling the concentration of the trisodium phosphate aqueous solution. The concentration of the trisodium phosphate aqueous solution works synergistically with the temperature to achieve the best cleaning effect.

[0031] This invention controls the cleaning time of the cleaning fluid to last 24-48 hours, ensuring that the interior of the shell-and-tube heat exchanger is thoroughly cleaned and that the system can be quickly restored to the use of cooling water for heat exchange and cooling of the crude syngas from coal chemical plants.

[0032] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An online cleaning device for a heat exchanger in a coal chemical syngas system, comprising a shell-and-tube heat exchanger (1), wherein the tube side inlet and outlet of the shell-and-tube heat exchanger (1) are respectively connected to a crude syngas inlet pipe (2) and a crude syngas outlet pipe (3), and the shell side inlet and outlet are respectively connected to a water inlet pipe (4) and a water outlet pipe (5); characterized in that, The shell side inlet and outlet are connected to a circulating cleaning pipe (6), and the circulating cleaning pipe (6) is connected to a chemical tank (7), a circulating pump (8), and a cooling device (9) for cooling the liquid in the circulating cleaning pipe (6); valves are provided on the inlet pipe (4), the outlet pipe (5), and the circulating cleaning pipe (6); the chemical tank (7) is connected to a circulating filter pipe (10), and a filter device (11) and a circulating pump (12) are connected on the circulating filter pipe (10), and valves are provided on the circulating filter pipe (10).

2. The online cleaning device for heat exchangers in a coal chemical syngas system as described in claim 1, characterized in that, The cooling device (9) includes a cooling heat exchanger (901) connected to the circulating cleaning pipe (6) and a chiller unit (902) connected to the cooling heat exchanger (901) via a pipe.

3. The online cleaning device for heat exchangers in a coal chemical syngas system as described in claim 2, characterized in that, An online pH monitor (14) for monitoring the pH value of the liquid inside the circulating filter tube (10) is connected to the circulating filter tube (10).

4. The online cleaning device for heat exchangers in a coal chemical syngas system as described in claim 1, characterized in that, A temperature sensor (13) for monitoring the temperature inside the circulating cleaning pipe (6) is connected to the circulating cleaning pipe (6). The temperature sensor (13) is electrically connected to a PID temperature controller, which is electrically connected to the cooling device (9).

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