A device for adding protective liquid for shutdown

Abstract

The utility model discloses a dosing device for shutdown protection liquid, and relates to a dosing device; it comprises a main water inlet pipe, a shutdown protection liquid soluble medicine box and a multi-stage centrifugal pump; the main water inlet pipe is provided with a main water inlet valve, and is divided into an upper water inlet pipe and a lower water inlet pipe after the main water inlet valve; the top of the shutdown protection liquid soluble medicine box is connected with the upper water inlet pipe, the bottom of the shutdown protection liquid soluble medicine box is provided with a lower medicine outlet pipe of the soluble medicine box, and the lower medicine outlet pipe of the soluble medicine box is connected with the lower water inlet pipe and then connected to the multi-stage centrifugal pump; a Y-type filter is provided at the inlet of the multi-stage centrifugal pump, and a lower water inlet pipe ball valve is provided at the lower water inlet pipe; the shutdown protection liquid soluble medicine box is provided with an overflow pipe, and the overflow pipe is connected with a sewage pipe; the outlet of the multi-stage centrifugal pump is connected with the outlet pipe of the multi-stage centrifugal pump, and a pressure gauge, a check valve and a float flowmeter are provided on the outlet pipe of the multi-stage centrifugal pump in sequence; the utility model solves the problems of dosing time and inconvenient operation of the existing dosing device.

Description

Technical Field

[0001] The utility model relates to a dosing device, in particular to a dosing device for shutdown protection liquid of a thermal power plant. Background Art

[0002] With the rapid development of new energy, the overcapacity of the power generation industry, and the continuous increase in power generation costs, traditional thermal power units are often in a state of long-term shutdown. Since the water in the unit cannot be completely drained during shutdown, if it is not properly maintained, the thermal equipment will be fully exposed to the atmosphere, and the water vapor system will produce more serious corrosion. In the long run, it will affect the safety of the unit, so anti-corrosion work during shutdown has become particularly important. Traditional shutdown protection methods include nitrogen filling method, waste heat drying method, ammonia-hydrazine method, vapor phase corrosion inhibitor method and film-forming amine method. Among them, the film-forming amine method has been widely used due to its advantages such as long protection period, good anti-corrosion effect and no impact on maintenance. The film-forming amine method is to inject organic amines into the thermal system through a dosing pump to form a dense, uniform monolayer adsorption film on the inner surface of the thermal system, which acts as a barrier to prevent oxygen, CO 2 Corrosion factors such as corrosion factors invade the metal surface, but in practice many power plants have not designed special shutdown protection liquid dosing pumps, and only use existing ammonia pumps and phosphate pumps for shutdown maintenance. The dosing time is too long, which seriously affects the shutdown process; or there are special shutdown protection liquid dosing pumps designed, but it is not convenient for operators to operate. Utility Model Content

[0003] The utility model overcomes the shortcomings of the prior art and provides a device for adding a protection liquid during shutdown, solving the problem of how to shorten the adding time and simplify the operation.

[0004] In order to achieve the above purpose, the utility model is implemented through the following technical solutions.

[0005] A shutdown protection liquid dosing device comprises a main water inlet pipe, a shutdown protection liquid dissolving medicine box and a multi-stage centrifugal pump for pumping the shutdown protection liquid into a thermal system; a main water inlet valve is arranged on the main water inlet pipe, and the main water inlet valve is divided into an upper water inlet pipe and a lower water inlet pipe after the main water inlet valve; the top of the shutdown protection liquid dissolving medicine box is connected with the upper water inlet pipe, the bottom of the shutdown protection liquid dissolving medicine box is provided with a lower medicine outlet pipe of the dissolving medicine box, and the lower medicine outlet pipe of the dissolving medicine box is connected with the lower water inlet pipe and then connected to the multi-stage centrifugal pump; a Y-type filter is arranged at the inlet of the multi-stage centrifugal pump, a lower water inlet pipe is provided with a lower water inlet pipe ball valve, and the shutdown protection liquid dissolving medicine box is provided with a Y-type filter at the inlet of the multi-stage centrifugal pump, a lower water inlet pipe ball valve is provided, and a ... lower water inlet pipe ball valve is provided. A sewage pipe is connected to the bottom of the box, and a sewage pipe ball valve is arranged on the sewage pipe; an overflow pipe is arranged on the shutdown protection liquid solution box, and the overflow pipe is connected to the sewage pipe; the outlet of the multistage centrifugal pump is connected to the multistage centrifugal pump outlet pipe, and a pressure gauge, a check valve and a float flowmeter are arranged on the multistage centrifugal pump outlet pipe in sequence; the multistage centrifugal pump outlet pipe is divided into two pipes after the float flowmeter: a condensate dosing pipe and a feed water dosing pipe, the condensate dosing pipe is connected to the condensate pump outlet, and a first outlet valve is arranged; the feed water dosing pipe is connected to the deaerator downcomer, and a second outlet valve is arranged.

[0006] Furthermore, a float valve is provided on the upper water inlet pipe to control the inflow of water, and the float of the float valve is arranged in the shutdown protection liquid-soluble medicine box.

[0007] Furthermore, a stirring device is provided at the top center of the shutdown protection liquid-soluble medicine box, and a stirring rod and blades of the stirring device extend below the float ball in the shutdown protection liquid-soluble medicine box.

[0008] Furthermore, an electrical control box for controlling the stirring device and the multi-stage centrifugal pump is also provided on the external side of the furnace shutdown protection liquid-soluble medicine box.

[0009] Furthermore, a drug outlet pipe ball valve is provided on the drug outlet pipe at the lower part of the drug dissolving box.

[0010] Furthermore, a drug adding port is provided on the top of the liquid-soluble medicine box for shutdown protection.

[0011] Furthermore, a liquid level gauge is provided on the side of the furnace shutdown protection liquid-soluble medicine box, and a liquid level gauge drain pipe is provided at the bottom of the liquid level gauge.

[0012] Furthermore, it also includes a base, and the shutdown protection liquid-soluble medicine box and the multi-stage centrifugal pump are arranged on the base.

[0013] The beneficial effects of the utility model compared with the prior art are:

[0014] The utility model uses a multi-stage centrifugal pump to shorten the original 3-6 hours to about 40 minutes, and the multi-stage centrifugal pump inlet dilutes the liquid medicine twice through the lower water inlet, making the dosing process more continuous and smooth, reducing the impact of stopping the furnace to dosing on the operation of the unit. At the same time, the upper water inlet pipe is controlled by a float valve, which simplifies the dilution and flushing process of the dosing, and is convenient for the operator to use.

[0015] The utility model is provided with two drug outlets, which are respectively connected to the condensate pump outlet and the deaerator downcomer, so as to change the drug addition to two points, fully protect the condensate system and the water supply system, and achieve a good drug addition effect while facilitating operation.

[0016] The utility model can ensure that the dosing pipeline is not blocked by setting the upper and lower water inlet pipelines and the Y-type filter, realize the functions of flushing, mixing, dosing and maintenance of the device, and operate the system through electrical control, making the whole process more convenient. It solves the problems of dosing time and inconvenient operation of the existing dosing device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front view of the shutdown protection liquid dosing device described in the utility model.

[0018] Figure 2 It is a right view of the shutdown protection liquid dosing device described in the utility model.

[0019] Figure 3 It is a left view of the shutdown protection liquid dosing device described in the utility model.

[0020] Figure 4 It is a top view of the shutdown protection liquid dosing device described in the utility model.

[0021] In the figure: 1-mixer, 2-upper water inlet pipe, 3-upper water inlet float valve, 4-water inlet main valve, 5-main water inlet pipe, 6-electrical control box, 7-lower water inlet pipe, 8-lower medicine outlet pipe of dissolving medicine box, 9-base, 10-Y-type filter, 11-pressure gauge, 12-outlet pipe ball valve, 13-check valve, 14-multistage centrifugal pump, 15-multistage centrifugal pump outlet pipe, 16-liquid level gauge, 17-boiler shutdown protection liquid dissolving medicine box, 18-dosing port, 19-overflow pipe, 20-drain pipe ball valve, 21-drain pipe, 22-lower water inlet pipe ball valve, 23-liquid level gauge drain valve, 24-drug outlet pipe ball valve, 25-condensate dosing pipe, 26-water dosing pipe, 27-first outlet valve, 28-second outlet valve. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail in combination with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The technical solution of the present invention is described in detail below in combination with the embodiments and the accompanying drawings, but the scope of protection is not limited thereto.

[0023] See also Figures 1 to 4This embodiment provides a shutdown protection liquid dosing device, which mainly includes a base 9, a shutdown protection liquid dissolving box 17 arranged on the base 9, and a multi-stage centrifugal pump 14 for pumping the shutdown protection liquid into the thermal system. The shutdown protection liquid dissolving box 17 is made of stainless steel, has a cylindrical shape, a hemispherical bottom, and a volume of 1.0m 3 -2.0 m 3 ; The head of the multistage centrifugal pump 14 is 4MPa-6MPa, and the output is 2 m 3 / h-3 m 3 / h.

[0024] A main water inlet valve 4 is provided on the main water inlet pipe 5, and the main water inlet valve 4 controls the switch of the water source. After the main water inlet valve 4, it is divided into an upper water inlet pipe 2 and a lower water inlet pipe 7; the top of the shutdown protection liquid-soluble medicine box 17 is connected to the upper water inlet pipe 2, and the upper water inlet pipe 2 is provided with a float valve 3 to control the inflow of water. When the liquid level in the shutdown protection liquid-soluble medicine box 17 is lower than the float ball in the box, the float valve 3 opens, and when the liquid level is higher than the float ball, the float valve 3 closes.

[0025] The top of the shutdown protection liquid medicine box 17 is provided with a medicine adding port 18, and the bottom of the shutdown protection liquid medicine box 17 is provided with a medicine box lower medicine outlet pipe 8, and the lower medicine box lower medicine outlet pipe 8 is provided with a medicine outlet pipe ball valve 24. The lower medicine outlet pipe 8 of the medicine box is connected to the lower water inlet pipe 7 and then connected to the multi-stage centrifugal pump 14. The function is to use desalted water to dilute the viscous medicine liquid again to reduce the burden of the multi-stage centrifugal pump 14 and prevent the pump from overloading. The inlet of the multi-stage centrifugal pump 14 is provided with a Y-type filter 10 to prevent impurities or foreign matter in the medicine box from entering the pump during operation. The lower water inlet pipe 7 is provided with a lower water inlet pipe ball valve 22 to play a role in regulating the water flow.

[0026] The bottom of the shutdown protection liquid soluble medicine box 17 is connected with a sewage pipe 21, and a sewage pipe ball valve 20 is arranged on the sewage pipe 21. The shutdown protection liquid soluble medicine box 17 is provided with an overflow pipe 19, and the overflow pipe 19 is connected with the sewage pipe 21.

[0027] A stirring device 1 is provided at the top center of the shutdown protection liquid medicine box 17. The stirring rod and blades of the stirring device 1 extend below the float in the shutdown protection liquid medicine box 17. Its function is to fully dilute the shutdown protection liquid and make it more uniform and stable during the dosing and flushing process.

[0028] The outlet of the multistage centrifugal pump 14 is connected to a multistage centrifugal pump outlet pipe 15, on which a pressure gauge 11, a check valve 13 and a float flowmeter 12 are arranged in sequence; the multistage centrifugal pump outlet pipe 15 is connected to the steam system of the boiler of the power plant, and the multistage centrifugal pump outlet pipe 15 is divided into two pipes after the float flowmeter 12: a condensate dosing pipe 25 and a feed water dosing pipe 26, the condensate dosing pipe 25 is connected to the condensate pump outlet and is provided with a first outlet valve 27; the feed water dosing pipe 26 is connected to the deaerator downcomer and is provided with a second outlet valve 28. The check valve 13 is to prevent the backflow of water vapor in the thermal system.

[0029] An electrical control box 6 for controlling the stirring device 1 and the multi-stage centrifugal pump 14 is provided on the outer side of the furnace shutdown protection liquid-soluble medicine box 17. A multi-stage centrifugal pump frequency conversion control module is arranged in the electrical control box 6 to receive flow signals. When the working condition of the system changes when the dosing point is switched, the frequency of the multi-stage centrifugal pump 14 is adjusted according to the flow signal fed back, and the outlet flow of the multi-stage centrifugal pump 14 is controlled to be constant. The float flowmeter 12 can monitor the outlet flow of the multi-stage centrifugal pump 14 and transmit the flow signal to the electrical control box 6. The electrical control box 6 can control the start and stop of the stirring device 1 and the multi-stage centrifugal pump 14, and can also control the frequency change of the multi-stage centrifugal pump 14 according to the flow signal transmitted back by the float flowmeter 12.

[0030] A liquid level gauge 16 is provided on the side of the shutdown protection liquid soluble medicine box 17 to facilitate monitoring of the liquid level height in the shutdown protection liquid soluble medicine box 17; a liquid level gauge drain pipe 23 is provided at the bottom of the liquid level gauge 16, and the residual liquid in the liquid level gauge 16 can be drained after the addition of medicine is completed to prevent the liquid from solidifying and blocking the liquid level gauge.

[0031] The process steps of adding shutdown protection liquid using the utility model are as follows:

[0032] Step 1: When using for the first time, open the water inlet main valve 4 and the lower water inlet pipe ball valve 22 to fill water into the shutdown protection liquid medicine box 17. After the medicine box is full of water, close the above valves, open the sewage pipe ball valve 20, flush the shutdown protection liquid medicine box 17, and repeat 2-3 times until there are no impurities in the shutdown protection liquid medicine box 17. Refill water into the shutdown protection liquid medicine box 17, perform system pressure test and trial operation debugging, and confirm that there is no leakage in the connecting pipeline and the dosing system operates normally.

[0033] Step 2: When the unit is shut down and needs to be dosed, first open the main water inlet valve 4, and inject water into the shutdown protection liquid soluble medicine box 17 through the upper water inlet pipe 2. When the liquid level in the box lifts the float, the water inlet stops, and the stirring device 1 is turned on. A certain amount (the specific amount is determined according to the capacity and model of the thermal power plant unit) of shutdown protection liquid is poured into the shutdown protection liquid soluble medicine box 17 through the dosing port 18 to allow the liquid to be fully and evenly stirred.

[0034] Step 3: First add medicine to the condensate system, open the lower water inlet pipe ball valve 22, the medicine outlet pipe ball valve 24, and the first outlet valve 27, dilute the medicine liquid with desalted water and flush it into the multi-stage centrifugal pump 14, start the multi-stage centrifugal pump 14, inject the shutdown protection liquid into the thermal system, appropriately reduce the opening of the lower water inlet pipe ball valve 22, and keep the liquid level of the shutdown protection liquid dissolving medicine box 17 in a downward trend. When the liquid level drops to two-thirds, open the second outlet valve 28, close the first outlet valve 27, and add medicine to the water supply system. At this time, the external system pressure changes and the frequency conversion control module can control the flow of the multi-stage centrifugal pump 14 at a constant value. During the dosing process, when the liquid level in the box is lower than the float, the float valve 3 is opened to inject water into the box. When the liquid level lifts the float, the float valve 3 is closed. This can keep the liquid level fluctuating in a constant range, eliminating the need for frequent monitoring of the liquid level. In addition, the shutdown protection liquid below the lower discharge pipe 8 of the solvent box can be fully added to the thermal system during the continuous dilution process to avoid waste.

[0035] Step 4: When the liquid in the shutdown protection liquid-soluble medicine box 17 becomes clear and its color is close to that of desalted water, it indicates that the dosing is completed, stop the multi-stage centrifugal pump 14, close the second outlet valve 28, and fill water into the shutdown protection liquid-soluble medicine box 17. After it is full of water, close the main water inlet valve 4 and the lower water inlet pipe ball valve 22, open the drain pipe ball valve 20 and the liquid level meter drain pipe 23, and close the above two valves after the water is drained. All operations of the shutdown protection dosing device are completed.

[0036] The above content is a further detailed description of the utility model in combination with a specific preferred implementation method. It cannot be determined that the specific implementation methods of the utility model are limited to this. For ordinary technicians in the technical field to which the utility model belongs, they can make several simple deductions or substitutions without departing from the utility model, which should be regarded as belonging to the utility model and the scope of patent protection determined by the submitted claims.

Claims

1. A shutdown protection liquid dosing device, characterized in that: The invention comprises a main water inlet pipe (5), a furnace shutdown protection liquid medicine box (17), and a multistage centrifugal pump (14) for pumping the furnace shutdown protection liquid into the thermal system; the main water inlet pipe (5) is provided with a main water inlet valve (4), and is divided into an upper water inlet pipe (2) and a lower water inlet pipe (7) after the main water inlet valve (4); the top of the furnace shutdown protection liquid medicine box (17) is connected to the upper water inlet pipe (2), the bottom of the furnace shutdown protection liquid medicine box (17) is provided with a medicine box lower medicine outlet pipe (8), the medicine box lower medicine outlet pipe (8) is connected to the lower water inlet pipe (7) and then connected to the multistage centrifugal pump (14); the inlet of the multistage centrifugal pump (14) is provided with a Y-type filter (10), the lower water inlet pipe (7) is provided with a lower water inlet pipe ball valve (22), and the bottom of the furnace shutdown protection liquid medicine box (17) is connected with a sewage pipe (21) , a sewage pipe ball valve (20) is provided on the sewage pipe (21); the shutdown protection liquid solution medicine box (17) is provided with an overflow pipe (19), and the overflow pipe (19) is connected to the sewage pipe (21); the outlet of the multistage centrifugal pump (14) is connected to the multistage centrifugal pump outlet pipe (15), and the multistage centrifugal pump outlet pipe (15) is provided with a pressure gauge (11), a check valve (13) and a float flowmeter (12) in sequence; the multistage centrifugal pump outlet pipe (15) is divided into two pipes after the float flowmeter (12): a condensate dosing pipe (25) and a feed water dosing pipe (26), the condensate dosing pipe (25) is connected to the condensate pump outlet, and is provided with a first outlet valve (27); the feed water dosing pipe (26) is connected to the deaerator downcomer, and is provided with a second outlet valve (28).

2. A shutdown protection liquid dosing device according to claim 1, characterized in that: The upper water inlet pipe (2) is provided with a float valve (3) to control the inflow of water, and the float of the float valve (3) is arranged in the furnace shutdown protection liquid solution box (17).

3. A shutdown protection liquid dosing device according to claim 2, characterized in that: A stirring device (1) is provided at the top center of the furnace shutdown protection liquid soluble medicine box (17), and a stirring rod and blades of the stirring device (1) extend below the float ball in the furnace shutdown protection liquid soluble medicine box (17).

4. A shutdown protection liquid dosing device according to claim 3, characterized in that: An electrical control box (6) for controlling the stirring device (1) and the multi-stage centrifugal pump (14) is also provided on the outer side of the furnace shutdown protection liquid-soluble medicine box (17).

5. The shutdown protection liquid dosing device according to claim 1 is characterized in that: A drug outlet pipe ball valve (24) is provided on the drug outlet pipe (8) at the lower part of the drug dissolving box.

6. The shutdown protection liquid dosing device according to claim 1, characterized in that: A medicine adding port (18) is provided on the top of the furnace shutdown protection liquid medicine box (17).

7. The shutdown protection liquid dosing device according to claim 1 is characterized in that: A liquid level gauge (16) is provided on the side of the furnace shutdown protection liquid solution medicine box (17), and a liquid level gauge drain pipe (23) is provided at the bottom of the liquid level gauge (16).

8. The shutdown protection liquid dosing device according to claim 1, characterized in that: It also comprises a base (9), on which the furnace shutdown protection liquid medicine tank (17) and the multi-stage centrifugal pump (14) are arranged.

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