A boiler steam drum blowdown water recovery system

Abstract

The invention discloses a boiler drum waste water recovery system, comprising a waste water tank, one end of which is connected to the drum, the other end of which is connected to a waste water cooler through a waste water pipe, the outlet end of the waste water cooler is connected to a ditch through a pipeline, a first stop valve, a pneumatic interlock regulating valve and a second stop valve are sequentially arranged on the waste water pipe, a first pipe is connected to the waste water pipe behind the pneumatic interlock regulating valve, the other end of the first pipe is connected to a pneumatic pump, the device air is delivered to the pneumatic pump through an air intake pipe, a second pipe is connected above the pneumatic pump, and the other end of the second pipe is connected to an external condensate pipe network through an external condensate delivery pipeline. The first pipe of the invention is led out from behind the pneumatic interlock regulating valve, which ensures that the waste water flashes to recover steam on the one hand, and avoids the situation of cross pressure in the pipeline on the other hand; the waste water is pressurized by the pneumatic pump, and the waste water is recovered, so as to save production costs and reduce resource waste.

Description

Technical Field

[0001] The invention relates to the technical field of boilers, and in particular to a boiler drum wastewater recovery system. Background Art

[0002] The steam drum is also called the gas-liquid separator. As the key equipment for the nitric acid plant to deliver high-pressure steam, the safe, stable and long-term operation of the steam drum plays a very important role in the entire nitric acid process system. The steam drum is the connecting hub of the three processes of heating, evaporation and superheating in the boiler system of the nitric acid plant. There is a certain amount of water in the steam drum, which can effectively slow down the change rate of the internal pressure of the system when the working conditions change, which is conducive to regulating and controlling the amount of steam. There is a gas-liquid separation device in the steam drum. The saturated steam is separated into gas and liquid in the steam separator to produce high-quality high-pressure steam. Although the boiler system uses desalted water, there are still a small amount of calcium ions and magnesium ions. For a long time, CaCO3, MgCO3 or Fe(OH)3 precipitates will accumulate at the bottom of the steam drum and in the boiler coil. This kind of scale is not conducive to heat transfer. Due to the presence of scale, the boiler coil must be heated to a very high temperature. At this time, the pipe material gradually oxidizes, causing it to lose its mechanical strength, which will eventually cause the waste heat boiler coil to explode. The explosion of the coil will break through the platinum mesh, causing huge losses. Therefore, it is necessary to discharge the steam drum to reduce the accumulation of scale at the bottom of the steam drum.

[0003] At present, the nitric acid plant requires continuous blowdown of the drum during normal production (blowdown volume 3m 3 / h), the sewage is mainly discharged into the sewage tank first, and then dynamically adjusted by the pneumatic interlock valve and DCS system to maintain 50% of the liquid level in the sewage tank. The remaining sewage is discharged through the sewage pipe to the sewage cooler for cooling and then discharged into the ditch. During the start-up of the nitric acid unit, in order to stabilize the drum liquid level, the sewage discharge volume will be increased (6m 3 / h or so); in the prior art, sewage is discharged into the ditch and flows into the rainwater network, but this part of water is desalted water, which will be wasted if not recycled. Therefore, it is necessary to recycle this water, but the pressure of the sewage is relatively low (about 0.05MPa), and the pressure of the system network is high. The sewage cannot be directly recycled to the system network, which brings difficulties to recycling. Summary of the invention

[0004] The purpose of the present invention is to provide a boiler drum wastewater recovery system to solve the problem that the wastewater pressure is low, the system pipe network pressure is high, and the wastewater cannot be directly recovered to the system pipe network.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The present invention discloses a boiler drum wastewater recovery system, comprising a wastewater tank, one end of which is connected to the drum, the other end of which is connected to a wastewater cooler through a wastewater pipe, the outlet end of the wastewater cooler is connected to a ditch through a pipeline, a first stop valve, a pneumatic interlock regulating valve and a second stop valve are sequentially arranged on the wastewater pipe, a first pipe is connected to the wastewater pipe behind the pneumatic interlock regulating valve, the other end of the first pipe is connected to a pneumatic pump, device air is transported to the pneumatic pump through an air intake pipe, a second pipe is connected above the pneumatic pump, and the other end of the second pipe is connected to an external condensate pipe network through an external condensate delivery pipeline.

[0007] Furthermore, a bypass pipe is provided on one side of the sewage pipe, one end of the bypass pipe is connected in front of the first stop valve, the other end of the bypass pipe is connected behind the second stop valve, and a third stop valve is provided on the bypass pipe.

[0008] Furthermore, the third stop valve is configured as a normally closed valve.

[0009] Furthermore, a fourth stop valve is provided on the first pipeline, and a fifth stop valve is provided on the second pipeline.

[0010] Furthermore, the first stop valve, the fourth stop valve and the fifth stop valve are configured as normally open valves, and the second stop valve is configured as a normally closed valve.

[0011] Compared with the prior art, the beneficial technical effects of the present invention are:

[0012] The present invention discloses a boiler drum wastewater recovery system, comprising a wastewater tank, one end of which is connected to the drum, the other end of which is connected to a wastewater cooler through a wastewater pipe, the outlet end of the wastewater cooler is connected to a ditch through a pipeline, a first stop valve, a pneumatic interlock regulating valve and a second stop valve are sequentially arranged on the wastewater pipe, a first pipe is connected to the wastewater pipe behind the pneumatic interlock regulating valve, the other end of the first pipe is connected to a pneumatic pump, the air of the device is delivered to the pneumatic pump through an air intake pipe, a second pipe is connected above the pneumatic pump, and the second pipe The other end of the pipeline is connected to the external condensate delivery network through an external condensate delivery pipeline; the first pipeline of the present invention is led out from behind the pneumatic interlock regulating valve, which on the one hand ensures the flash evaporation of sewage to recover steam, and on the other hand avoids the situation of pipeline cross pressure; the sewage is pressurized by a pneumatic pump to match the pressure of the sewage with the pressure of the external condensate delivery network, which is convenient for conveying the sewage to the external condensate delivery network and recovering the sewage. The air of the device is introduced nearby by the pneumatic pump as the power source of the air pump, which reduces the difficulty of electrical wiring construction, saves production costs, and reduces resource waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be further described below in conjunction with the accompanying drawings.

[0014] Figure 1 It is a schematic structural diagram of the sewage recovery system of the boiler steam drum of the present invention;

[0015] Explanation of reference numerals in the drawings: 1. sewage discharge tank; 2. sewage discharge pipeline; 3. bypass pipeline; 4. first stop valve; 5. pneumatic interlock regulating valve; 6. second stop valve; 7. third stop valve; 8. sewage cooler; 9. first pipeline; 10. fourth stop valve; 11. pneumatic pump; 12. second pipeline; 13. fifth stop valve; 14. air inlet pipeline; 15. external condensate network; 16. external condensate pipeline. Specific embodiments

[0016] As Figure 1 shown, a sewage recovery system for a boiler steam drum includes a sewage discharge tank 1, one end of the sewage discharge tank 1 is connected to the steam drum, the other end of the sewage discharge tank 1 is connected to a sewage cooler 8 through a sewage discharge pipeline 2, the outlet end of the sewage cooler 8 is communicated with a trench through a pipeline, a first stop valve 4, a pneumatic interlock regulating valve 5 and a second stop valve 6 are sequentially arranged on the sewage discharge pipeline 2, a first pipeline 9 is connected to the sewage discharge pipeline 2 behind the pneumatic interlock regulating valve 5, the other end of the first pipeline 9 is connected to a pneumatic pump 11, device air is supplied to the pneumatic pump 11 through an air inlet pipeline 14, a second pipeline 12 is connected above the pneumatic pump 11, and the other end of the second pipeline 12 is connected to an external condensate network 15 through an external condensate pipeline 16; the first pipeline 9 is led out from behind the pneumatic interlock regulating valve 5, on the one hand, it ensures the flashing and recovery of steam from the sewage discharge, and on the other hand, it avoids the situation of pressure crossover in the pipeline; the present invention retains the connecting pipeline between the sewage discharge pipeline 2 and the sewage cooler 8 in the prior art. Once the reformed pipeline or equipment malfunctions and sewage cannot be discharged, when the fourth stop valve 10 is closed and the second stop valve 6 is opened, this pipeline can still be used for normal sewage discharge to ensure the normal continuous sewage discharge of the steam drum; the present invention pressurizes the sewage discharge through a pneumatic pump 11 to make the pressure of the sewage discharge match the pressure of the external condensate network 15, facilitating the transportation of the sewage discharge into the external condensate network 15 for sewage recovery. The device air is used as the power source of the air pump near the pneumatic pump 11, reducing the difficulty of electrical wiring construction; the construction cost of the project of the present invention is 10,000 yuan. After the project is put into use, a large amount of desalted water waste is reduced. The annual water recovery volume can be 24,000 m 3 , and the desalted water is 8 yuan per ton, saving 192,000 yuan annually, saving production costs and reducing resource waste.

[0017] Specifically, a bypass pipeline 3 is arranged on one side of the sewage discharge pipeline 2. One end of the bypass pipeline 3 is connected in front of the first stop valve 4, and the other end of the bypass pipeline 3 is connected behind the second stop valve 6. A third stop valve 7 is arranged on the bypass pipeline 3; when the sewage discharge pipeline 2 is abnormal or the pneumatic interlock control valve 5 is damaged, the third stop valve 7 is opened, and sewage is discharged through the bypass pipeline 3 to maintain the normal liquid level of the sewage discharge tank 1.

[0018] The third stop valve 7 is set as a normally closed valve.

[0019] A fourth stop valve 10 is arranged on the first pipeline 9, and a fifth stop valve 13 is arranged on the second pipeline 12.

[0020] The first stop valve 4, the fourth stop valve 10 and the fifth stop valve 13 are set as normally open valves, and the second stop valve 6 is set as a normally closed valve.

[0021] The use process of the present invention is as follows:

[0022] First, the blowdown water from the steam drum is first discharged into the sewage discharge tank 1, and then the liquid level of the sewage discharge tank is dynamically adjusted and maintained at 50% through the pneumatic interlock control valve 5 and the DCS system. The remaining sewage enters the first pipeline 9 through the sewage discharge pipeline 2. The air of the device is transported to the pneumatic pump 11 through the air inlet pipeline 14. The pneumatic pump 11 pressurizes the sewage. The sewage with a higher pressure is connected to the external condensate pipeline 16 through the second pipeline 12 and is transported to the external condensate pipe network 15 through the external condensate pipeline 16 to achieve the purpose of sewage recovery.

[0023] The embodiments described above are only used to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solution of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A boiler drum waste water recovery system, comprising a waste water tank, one end of which is connected to the drum, the other end of which is connected to a waste water cooler through a waste water pipe, the outlet end of the waste water cooler is connected to a ditch through a pipeline, and a first stop valve, a pneumatic interlock regulating valve and a second stop valve are sequentially arranged on the waste water pipe. Features: A first pipe is connected to the sewage pipe behind the pneumatic interlock regulating valve, and the other end of the first pipe is connected to a pneumatic pump. The device air is transported to the pneumatic pump through an air intake pipe. A second pipe is connected above the pneumatic pump, and the other end of the second pipe is connected to an external condensate pipe network through an external condensate pipe line; a bypass pipe is arranged on one side of the sewage pipe, one end of the bypass pipe is connected to the front of the first stop valve, and the other end of the bypass pipe is connected to the back of the second stop valve, and a third stop valve is arranged on the bypass pipe; a fourth stop valve is arranged on the first pipe, and a fifth stop valve is arranged on the second pipe.

2. The boiler drum wastewater recovery system according to claim 1, Features: The third stop valve is configured as a normally closed valve.

3. The boiler drum wastewater recovery system according to claim 1, Features: The first stop valve, the fourth stop valve and the fifth stop valve are configured as normally open valves, and the second stop valve is configured as a normally closed valve.

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