Circulating alkali washing system for heat exchanger

Abstract

The circulating alkali washing system comprises a waste oil tank, and a liquid inlet, a first reflux inlet, a liquid outlet and a second reflux inlet are formed in the waste oil tank; the liquid inlet is communicated with an alkali liquor inlet pipe, the liquid outlet is communicated with an alkali liquor outlet pipe, the alkali liquor outlet pipe is communicated with an alkali liquor pump and a cleaning header pipe, the first reflux inlet is communicated with a reflux header pipe, the second reflux inlet is communicated with a liquid return pipe and the cleaning header pipe, the liquid inlet end of the ammonia water removal cooler is communicated with a liquid inlet main pipe, and the liquid outlet end of the ammonia water removal cooler is communicated with a liquid outlet main pipe; a bypass pipeline and a backflow branch pipe led out from the liquid inlet main pipe are connected in parallel on the sides of the liquid inlet main pipe and the liquid outlet main pipe, the backflow branch pipe is communicated with a backflow main pipe, a cleaning branch pipe is led out from the liquid outlet main pipe, the cleaning branch pipe is communicated with a cleaning main pipe, and a branch cleaning valve is installed on the cleaning branch pipe. When the ammonia water removal cooler is blocked and the heat exchange effect is poor, the alkali washing investment cost is low, the workload of workers is small, the operation process is simple and convenient, and safe and stable operation of the device is effectively guaranteed.

Description

Technical Field

[0001] The present application relates to a cleaning device, and in particular to a heat exchanger circulating alkali cleaning system. Background Art

[0002] In the coal chemical production process, the phenol-ammonia recovery unit mainly processes the product gas water provided by the gas-water separation unit. In the actual production process, the oil content in the product gas water often exceeds the oil content in the originally designed product gas water, resulting in excessive oil content in the raw phenol water entering the phenol recovery unit. The deacidification and deamination towers of the phenol recovery unit can only remove a small amount of low-boiling light hydrocarbons in the oil. Most of the oil leaves the deamination tower with the deamination water, and is cooled from 113°C to 45°C by heat exchange in the deamination water cooler. The temperature decreases and the viscosity of the oil in the deamination water increases, and it adheres to the surface of the deamination water cooler tube bundle. As time goes by, the oil stains attached to the surface of the tube bundle gradually increase, which leads to a decrease in the heat exchange effect of the heat exchanger, causing the extraction system to overheat and the device to be forced to operate at a reduced load.

[0003] When the heat exchanger is clogged, the existing technology usually adopts high-pressure water flushing. Before flushing, not only the upper and lower heads must be removed, but also the tube bundles must be cleaned one by one. Each cleaning time is at least 4 to 5 days. Not only is the workload large, but it is also time-consuming, which seriously restricts the full-load stable operation of the device. Summary of the invention

[0004] The present application provides a heat exchanger circulating alkali cleaning system which reduces the cleaning workload and time.

[0005] The purpose of the present application is achieved as follows: A heat exchanger circulating alkali washing system includes a waste oil tank, wherein the waste oil tank is provided with a liquid inlet and a first reflux port at the upper end surface, and a liquid outlet and a second reflux port at the lower end surface;

[0006] The liquid inlet is connected to the alkali liquid inlet pipe and is equipped with an alkali inlet valve;

[0007] The liquid outlet is connected to the alkali solution outlet pipe, the alkali solution outlet pipe is connected to the liquid inlet of the alkali solution pump, the liquid outlet of the alkali solution pump is connected to the cleaning main pipe, a cleaning main valve is installed on the cleaning main pipe, and an alkali outlet valve is installed on the alkali solution outlet pipe;

[0008] The first reflux port is connected to the reflux main pipe and is equipped with a first reflux valve and a second reflux valve;

[0009] The second reflux port is connected to a liquid return pipe, the liquid inlet end of the liquid return pipe is connected to the cleaning main pipe, and a liquid return valve is installed on the liquid return pipe;

[0010] The liquid inlet end of the deammoniation water cooler is connected with a liquid inlet main pipe, on which a first liquid inlet valve is installed; the liquid outlet end of the deammoniation water cooler is connected with a liquid outlet main pipe, on which a first liquid outlet valve is installed; a bypass pipeline is connected in parallel to the liquid inlet main pipe and the liquid outlet main pipe, on which a bypass valve is installed; the liquid inlet end of the bypass pipeline is connected with the liquid inlet main pipe, and the liquid outlet end of the bypass pipeline is connected with the liquid outlet main pipe;

[0011] A reflux branch pipe is led out from the liquid inlet main pipe on the front side of the first liquid inlet valve, and the reflux branch pipe is connected to the reflux main pipe. A branch reflux valve is installed on the reflux branch pipe. A cleaning branch pipe is led out from the liquid outlet main pipe on the rear side of the first liquid outlet valve, and the cleaning branch pipe is connected to the cleaning main pipe. A branch cleaning valve is installed on the cleaning branch pipe. The liquid inlet end of the bypass pipeline is connected to the liquid inlet main pipe on the front side of the first liquid inlet valve, and the liquid outlet end of the bypass pipeline is connected to the liquid outlet main pipe on the rear side of the first liquid outlet valve.

[0012] A drain outlet is opened at the bottom of the deammoniation water cooler, the inner port of the drain outlet is connected to the inside of the deammoniation water cooler, the outer port of the drain outlet is connected to a drain branch pipe, the drain end of the drain branch pipe is connected to a drain main pipe, a drain valve is installed on the drain branch pipe, and a drain main valve is installed on the drain main pipe.

[0013] A sewage main pipe is led out from the return main pipe between the first return valve and the second return valve, and a sewage valve is installed on the sewage main pipe.

[0014] The drainage main is also connected to the return main.

[0015] This application utilizes the saponification reaction of oil and sodium hydroxide, and the reaction product is easily soluble in water. A dirty oil tank is added next to the deammoniation water heat exchanger. A lye pump is provided at the bottom of the dirty oil tank. The outlet of the lye pump is connected to the deammoniation water pipeline at the inlet of the deammoniation water heat exchanger. The oily waste liquid after washing is discharged from the outlet of the deammoniation water heat exchanger in two ways, one of which is connected to the top of the dirty oil tank for recycling, and the other is discharged to the gas-water separation device for sewage treatment after alkali washing. During alkali washing, the alkali liquid comes from the alkali liquid pipeline network, and the amount used each time is 1t. In order to improve the alkali washing effect, increase the solubility of fatty acid sodium and glycerol in water, and shorten the cleaning time, 113℃ deammoniation water is added to the alkali liquid to reduce the alkali concentration and increase the temperature of the alkali washing liquid. Then, the alkali pump and the dirty oil tank are used for cyclic cleaning until the cleaning is qualified. The heat exchanger generally takes no more than 16 hours from the start of isolation to the end of alkali washing, which shortens the cleaning time of the heat exchanger. When the deammoniation water cooler is blocked and the heat exchange effect is poor, the heat exchanger is cut out and isolated. The investment cost of alkaline cleaning is small through this application, the workload of workers is small, the operation process is simple and convenient, and each cleaning can save at least 4 days of cleaning time, which saves maintenance costs and minimizes the impact of heat exchanger blockage, effectively ensuring the safe and stable operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The specific structure of this application is given by the following drawings and embodiments:

[0017] Attached Figure 1 It is a schematic diagram of the structure of this application;

[0018] Attached Figure 2 It is a schematic diagram of the structure of the present application when multiple deammoniation water coolers are connected in series.

[0019] Legend: 1. Main pipe, 2. Bypass pipeline, 3. Deammoniation water cooler, 4. Cleaning branch pipe, 5. Drainage main pipe, 6. Drainage branch pipe, 7. Cleaning main pipe, 8. Return pipe, 9. Alkali solution pump, 10. Alkali solution outlet pipe, 11. Waste oil tank, 12. Alkali solution inlet pipe, 13. Reflux main pipe, 14. Reflux branch pipe, 15. Sewage main pipe, 16. Bypass branch pipe.

[0020] V01, bypass valve, V02, first liquid inlet valve, V03, first liquid outlet valve, V04, branch cleaning valve, V05, branch reflux valve, V06, first reflux valve, V07, alkali inlet valve, V08, alkali outlet valve, V09, main cleaning valve, V10, sewage valve, V11, second reflux valve, V12, drain valve, V13, main drain valve, V14, second liquid inlet valve, V15, second liquid outlet valve, V16, third liquid inlet valve, V17, third liquid outlet valve, V18, liquid return valve. Implementation

[0021] The present application is not limited by the following embodiments, and the specific implementation method can be determined according to the technical solution of the present application and actual conditions.

[0022] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached manual. Figure 1 The layout is described in detail, such as the positional relationship of top, bottom, left, right, etc. is based on the instructions attached to the manual. Figure 1 It is determined by the layout direction.

[0023] The present invention is explained below in conjunction with the accompanying drawings and embodiments: Embodiment 1, as Figure 1 As shown, a heat exchanger circulating alkali washing system includes a waste oil tank 11, wherein the waste oil tank 11 is provided with a liquid inlet and a first reflux port at the upper end surface, and a liquid outlet and a second reflux port at the lower end surface;

[0024] The liquid inlet is connected to the alkali liquid inlet pipe 12 and is equipped with an alkali inlet valve V07;

[0025] The liquid outlet is connected to the alkali solution outlet pipe 10, the alkali solution outlet pipe 10 is connected to the liquid inlet of the alkali solution pump 9, the liquid outlet of the alkali solution pump 9 is connected to the cleaning main pipe 7, a cleaning main valve V09 is installed on the cleaning main pipe 7, and an alkali outlet valve V08 is installed on the alkali solution outlet pipe 10;

[0026] The first reflux port is connected to the reflux main pipe 13 and is equipped with a first reflux valve V06 and a second reflux valve V11;

[0027] The second reflux port is connected to the liquid return pipe 8, the liquid inlet end of the liquid return pipe 8 is connected to the cleaning main pipe 7, and a liquid return valve V18 is installed on the liquid return pipe 8;

[0028] The liquid inlet end of the deammoniation water cooler 3 is connected with a liquid inlet main pipe 1, on which a first liquid inlet valve V02 is installed; the liquid outlet end of the deammoniation water cooler 3 is connected with a liquid outlet main pipe, on which a first liquid outlet valve V03 is installed; a bypass pipeline 2 is connected in parallel to the liquid inlet main pipe 1 and the liquid outlet main pipe side, on which a bypass valve V01 is installed; the liquid inlet end of the bypass pipeline 2 is connected with the liquid inlet main pipe 1, and the liquid outlet end of the bypass pipeline 2 is connected with the liquid outlet main pipe;

[0029] A reflux branch pipe 14 is led out from the liquid inlet main pipe 1 on the front side of the first liquid inlet valve V02, and the reflux branch pipe 14 is connected to the reflux main pipe 13. A branch reflux valve V05 is installed on the reflux branch pipe 13. A cleaning branch pipe 4 is led out from the liquid outlet main pipe on the rear side of the first liquid outlet valve V03, and the cleaning branch pipe 4 is connected to the cleaning main pipe 7. A branch cleaning valve V04 is installed on the cleaning branch pipe 4. The liquid inlet end of the bypass pipeline 2 is connected to the liquid inlet main pipe 1 on the front side of the first liquid inlet valve V02, and the liquid outlet end of the bypass pipeline 2 is connected to the liquid outlet main pipe on the rear side of the first liquid outlet valve V03.

[0030] Furthermore, a drain port is provided at the bottom of the deammoniation water cooler 3, the inner port of the drain port is connected to the inside of the deammoniation water cooler 3, the outer port of the drain port is connected to the drain branch pipe 6, and the drain end of the drain branch pipe 6 is connected to the drain main pipe 5. A drain valve V12 is installed on the drain branch pipe 6, and a drain main valve V13 is installed on the drain main pipe 5.

[0031] Furthermore, a sewage main pipe 15 is led out from the return main pipe 13 between the first return valve V06 and the second return valve V11 , and a sewage valve V10 is installed on the sewage main pipe 15 .

[0032] Furthermore, the drainage main pipe 5 is also connected to the return main pipe 13.

[0033] The above-mentioned deammoniation water cooler 3 is a prior art, and its specific structure is not the invention of this application, and will not be described in detail here. The above-mentioned waste oil tank 11 is a hollow body, which is used to hold liquid.

[0034] When cleaning, close the first liquid inlet valve V02 and the first liquid outlet valve V03, open the bypass valve V01, and the deammoniation water introduced by the phenol water secondary heat exchanger is diverted by the bypass pipeline 2. Then open the alkali inlet valve V07 to inject alkali solution into the dirty oil tank 11. When the liquid level in the dirty oil tank 11 reaches the high liquid level, close the alkali inlet valve V07, open the branch cleaning valve V04, the branch reflux valve V05, the first reflux valve V06, the alkali outlet valve V08, the second reflux valve V11, and the liquid return valve V18, start the alkali pump 9, and pump the alkali solution into the deammoniation water cooler 3 from the liquid outlet end. The alkali solution will circulate and clean the deammoniation water cooler 3 through the alkali outlet pipe 10, the cleaning main pipe 7, the cleaning branch pipe 4, the reflux branch pipe 14, and the reflux main pipe 13. The liquid return valve V18 is opened when the deammoniation water cooler 3 is seriously blocked. The alkali liquid entering pressure will be relatively large to prevent the deammoniation water cooler 3 from bursting due to excessive pressure. When the pressure is relatively high, part of the alkali liquid will flow back from the liquid return pipe 8 to the waste oil tank 11.

[0035] After the deammoniation water cooler 3 is no longer blocked, the circulation cleaning is completed. At this time, the sewage valve V10 is opened, the second reflux valve V11 is closed, and the cleaned alkali solution is discharged from the sewage main pipe 15.

[0036] After all the alkali liquid is drained, close the branch cleaning valve V04, branch reflux valve V05, first reflux valve V06, alkali outlet valve V08, sewage valve V10, second reflux valve V11, and liquid return valve V18, and stop the alkali liquid pump 9. Open the first liquid inlet valve V02, drainage valve V12, and main drainage valve V13, and inject high-temperature deammoniation water into the deammoniation water cooler 3 for flushing. The deammoniation water after flushing is discharged from the drainage branch pipe 6 and the drainage main pipe 5 to the dust-containing gas water expander.

[0037] After cleaning, the drain valve V12 and the main drain valve V13 are closed, the first liquid outlet valve V03 is opened, the deammoniation water cooler 3 is put back into use, and the bypass valve V01 is closed.

[0038] Embodiment 2, when multiple deammoniation water coolers 3 are used in series, the liquid inlet end of the bypass pipeline 2 is connected to the liquid inlet main pipe 1 of the deammoniation water cooler 3 located at the front side, the liquid outlet end of the bypass pipeline 2 is connected to the liquid outlet main pipe of the deammoniation water cooler 3 located at the rear side, the liquid outlet main pipe of each deammoniation water cooler 3 is connected to the liquid inlet main pipe 1 of the adjacent rear side deammoniation water cooler 3, a bypass branch pipe 16 is led out at the connection point, the bypass branch pipe 16 is connected to the bypass pipeline 2, and each bypass branch pipe 16 is connected in parallel. A bypass valve is installed on the bypass pipeline 2 between each bypass branch pipe 16, and the bypass valve corresponds to the deammoniation water cooler 3 one by one.

[0039] Furthermore, a reflux branch pipe is led out from the liquid inlet main pipe of each deammoniation water cooler 3, and the reflux branch pipe is connected to the reflux main pipe 13. A branch reflux valve is installed on the reflux branch pipe. A cleaning branch pipe is led out from the liquid outlet main pipe, and the cleaning branch pipe is connected to the cleaning main pipe 7. A branch cleaning valve is installed on the cleaning branch pipe.

[0040] A drain port is provided at the bottom of each deammoniation water cooler 3 , and the drain port is connected to a drain branch pipe 6 , and a drain end of the drain branch pipe 6 is connected to a drain main pipe 5 .

[0041] When the deammoniation water heat exchanger is put into use normally, the first liquid inlet valve V02, the first liquid outlet valve V03, the second liquid inlet valve V14, the second liquid outlet valve V15, the third liquid inlet valve V16, and the third liquid outlet valve V17 are in the open state, and the remaining valves are in the closed state.

[0042] When the heat exchange effect of the deammonium water heat exchanger 3 located at the front side is not good, the first liquid inlet valve V02 and the first liquid outlet valve V03 are closed, and the bypass valve V01 is opened, and the deammonium water introduced from the phenol water secondary heat exchanger is guided to the subsequent deammonium water heat exchangers B and C through the bypass pipeline 2 and the bypass branch pipe 16. Then, the alkali inlet valve V07 is opened to inject alkali solution into the dirty oil tank 11. When the liquid level in the dirty oil tank 11 reaches the high liquid level, the alkali inlet valve V07 is closed, the branch cleaning valve V04, the branch reflux valve V05, the first reflux valve V06, the alkali outlet valve V08, the second reflux valve V11, and the liquid return valve V18 are opened, and the alkali pump 9 is started to pump the alkali solution into the deammonium water cooler 3 from the liquid outlet end. The alkali solution will be circulated and cleaned in the deammonium water cooler 3 through the alkali outlet pipe 10, the cleaning main pipe 7, the cleaning branch pipe 4, the reflux branch pipe 14, and the reflux main pipe 13. The liquid return valve V18 is opened when the deammoniation water cooler 3 is seriously blocked. The alkali liquid entering pressure will be relatively large to prevent the deammoniation water cooler 3 from bursting due to excessive pressure. When the pressure is relatively high, part of the alkali liquid will flow back from the liquid return pipe 8 to the waste oil tank 11.

[0043] After the deammoniation water cooler 3 is no longer blocked, the circulation cleaning is completed. At this time, the sewage valve V10 is opened, the second reflux valve V11 is closed, and the cleaned alkali solution is discharged from the sewage main pipe 15.

[0044] After all the alkali liquid is drained, close the branch cleaning valve V04, branch reflux valve V05, first reflux valve V06, alkali outlet valve V08, sewage valve V10, second reflux valve V11, and liquid return valve V18, and stop the alkali liquid pump 9. Open the first liquid inlet valve V02, drainage valve V12, and main drainage valve V13, and inject high-temperature deammoniation water into the deammoniation water cooler 3 for flushing. The deammoniation water after flushing is discharged from the drainage branch pipe 6 and the drainage main pipe 5 to the dust-containing gas water expander.

[0045] After cleaning, the drain valve V12 and the main drain valve V13 are closed, the first liquid outlet valve V03 is opened, the deammoniation water cooler 3 located at the front side is put back into use, and the bypass valve V01 is closed.

[0046] This application utilizes the saponification reaction of oil and sodium hydroxide, and the reaction product is easily soluble in water. A dirty oil tank 11 is added next to the deammoniation water heat exchanger. A lye pump 9 is provided at the bottom of the dirty oil tank 11. The outlet of the lye pump 9 is connected to the deammoniation water pipeline at the inlet of the deammoniation water heat exchanger 3. The oily waste liquid after washing is discharged from the outlet of the deammoniation water heat exchanger 3 in two ways, one of which is connected to the top of the dirty oil tank 11 for recycling, and the other is discharged to the gas-water separation device for sewage treatment after the alkali washing is qualified. During the alkali washing, the alkali liquid comes from the alkali liquid pipeline network, and the amount used each time is 1t. In order to improve the alkali washing effect, increase the solubility of fatty acid sodium and glycerol in water, and shorten the washing time, 113℃ deammoniation water is added to the alkali liquid to reduce the alkali concentration and increase the temperature of the alkali washing liquid. Then, the alkali pump 9 and the dirty oil tank 11 are used for circulation and washing until the washing is qualified. The deammoniation water heat exchanger 3 generally takes no more than 16 hours from the beginning of isolation to the end of alkali washing, which shortens the cleaning time of the heat exchanger.

[0047] The above description is only an example for clearly explaining the present application, and is not intended to limit the implementation methods of the present application. Any obvious changes or modifications derived from the technical solution of the present application are still within the scope of protection of the present application.

Claims

1. A heat exchanger circulating alkali washing system, characterized in that: It comprises a waste oil tank, wherein the upper end surface of the waste oil tank is provided with a liquid inlet and a first reflux port, and the lower end surface of the waste oil tank is provided with a liquid outlet and a second reflux port; The liquid inlet is connected to the alkali liquid inlet pipe and is equipped with an alkali inlet valve; The liquid outlet is connected to the alkali solution outlet pipe, the alkali solution outlet pipe is connected to the liquid inlet of the alkali solution pump, the liquid outlet of the alkali solution pump is connected to the cleaning main pipe, a cleaning main valve is installed on the cleaning main pipe, and an alkali outlet valve is installed on the alkali solution outlet pipe; The first reflux port is connected to the reflux main pipe and is equipped with a first reflux valve and a second reflux valve; The second reflux port is connected to a liquid return pipe, the liquid inlet end of the liquid return pipe is connected to the cleaning main pipe, and a liquid return valve is installed on the liquid return pipe; The liquid inlet end of the deammoniation water cooler is connected with a liquid inlet main pipe, on which a first liquid inlet valve is installed; the liquid outlet end of the deammoniation water cooler is connected with a liquid outlet main pipe, on which a first liquid outlet valve is installed; a bypass pipeline is connected in parallel to the liquid inlet main pipe and the liquid outlet main pipe, on which a bypass valve is installed; the liquid inlet end of the bypass pipeline is connected with the liquid inlet main pipe, and the liquid outlet end of the bypass pipeline is connected with the liquid outlet main pipe; A reflux branch pipe is led out from the liquid inlet main pipe on the front side of the first liquid inlet valve, and the reflux branch pipe is connected to the reflux main pipe. A branch reflux valve is installed on the reflux branch pipe. A cleaning branch pipe is led out from the liquid outlet main pipe on the rear side of the first liquid outlet valve, and the cleaning branch pipe is connected to the cleaning main pipe. A branch cleaning valve is installed on the cleaning branch pipe. The liquid inlet end of the bypass pipeline is connected to the liquid inlet main pipe on the front side of the first liquid inlet valve, and the liquid outlet end of the bypass pipeline is connected to the liquid outlet main pipe on the rear side of the first liquid outlet valve.

2. A heat exchanger circulating alkali cleaning system according to claim 1, characterized in that: A drain outlet is opened at the bottom of the deammoniation water cooler, the inner port of the drain outlet is connected to the inside of the deammoniation water cooler, the outer port of the drain outlet is connected to a drain branch pipe, the drain end of the drain branch pipe is connected to a drain main pipe, a drain valve is installed on the drain branch pipe, and a drain main valve is installed on the drain main pipe.

3. A heat exchanger circulating alkali cleaning system according to claim 1, characterized in that: A sewage main pipe is led out from the return main pipe between the first return valve and the second return valve, and a sewage valve is installed on the sewage main pipe.

4. A heat exchanger circulating alkali cleaning system as claimed in claim 2, characterized in that: The drainage main is also connected to the return main.

5. A heat exchanger circulating alkali washing system as claimed in claim 1, 2, 3 or 4, characterized in that: When multiple deammoniation water coolers are used in series, the liquid inlet end of the bypass pipeline is connected to the liquid inlet main pipe of the deammoniation water cooler located at the front side, and the liquid outlet end of the bypass pipeline is connected to the liquid outlet main pipe of the deammoniation water cooler located at the rear side. The liquid outlet main pipes of each deammoniation water cooler are connected to the liquid inlet main pipe of the adjacent rear deammoniation water cooler. A bypass branch pipe is led out at the connecting point, and the bypass branch pipe is connected to the bypass pipeline, and each bypass branch pipe is connected in parallel.

6. A heat exchanger circulating alkali cleaning system as claimed in claim 5, characterized in that: Bypass valves are installed on the bypass pipelines between the bypass branches, and the bypass valves correspond to the deammoniation water coolers one by one.

7. A heat exchanger circulating alkali cleaning system as claimed in claim 5, characterized in that: A reflux branch pipe is led out from the liquid inlet main pipe of each deammoniation water cooler, and a cleaning branch pipe is led out from the liquid outlet main pipe.

8. A heat exchanger circulating alkali cleaning system as claimed in claim 5, characterized in that: A drain outlet is provided at the bottom of each deammoniation water cooler.

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