A seawater desalination flash chamber water inlet pipeline efficiency and noise reduction reconstruction structure

Abstract

The utility model discloses a kind of seawater desalination flash chamber water inlet pipeline synergism noise reduction reconstruction structure, belong to seawater desalination technical field.Aiming at the uneven water distribution of existing flash chamber water inlet mode, low flash efficiency, small water treatment capacity, large pressure difference, severe vibration noise and the problem that it is difficult to implement large-diameter reconstruction due to narrow space limitation, the utility model uses DN700 hot water inlet to extend the water inlet pipe to the flash chamber water inlet side, and sets the spray water distribution assembly prefabricated outside in the flash chamber, the assembly includes spray main pipe and spray branch pipe with nozzle;At the same time, open flash flow-through hole at the flash chamber water inlet side and cancel the baffle plate of the outer wall of this side.The utility model realizes uniform water distribution, significantly improves the water treatment capacity of single device, effectively reduces equipment vibration and operating noise, restores the pressure difference to the reasonable range of design, and adapts to narrow space fast installation.

Description

Technical Field

[0001] This utility model relates to the field of seawater desalination technology, specifically to a structure for improving efficiency and reducing noise in the inlet pipe of a flash evaporator. Background Technology

[0002] At coastal power plants or island freshwater supply sites, low-temperature multi-effect distillation (MED) seawater desalination units typically require continuous 24-hour operation. Taking a MED system with a daily desalination capacity of 10,000 tons as an example, its flash chamber operates in a high-temperature seawater environment exceeding 60°C. During operation, high-temperature concentrated brine from the preceding effects rushes in through the inlet pipe at the bottom of the flash chamber, directly impacting the solid baffle plate installed on the outer wall of the flash chamber's inlet side. Water can only be forced into the flash chamber from the edge of the baffle plate and a few overflow holes.

[0003] Because the baffle is a solid, integral structure, the flow area is limited and the flow direction changes abruptly. This results in intense turbulence on the water-facing side in front of the baffle and a large vortex zone behind it. Standing on the outer platform of the flash evaporator, personnel can clearly perceive continuous low-frequency vibrations from the shell, accompanied by a muffled water-impact sound and cavitation noise; the equipment's operating noise often exceeds 85 dB. Simultaneously, the pressure difference between the flash chamber and the first-effect evaporator chamber remains consistently large, forcing operators to frequently adjust valves to maintain system vacuum balance.

[0004] Due to the uneven water distribution, turbulent flow field, and violent water flow impact, a large amount of hot water falls directly down before it has fully flashed, resulting in the actual water processing capacity of a single unit hovering between 60t / h and 70t / h for a long time, and low flashing efficiency. After long-term operation, leakage occurred at the interface between the heat exchange tubes and the tube sheet due to vibration fatigue, and cracks also appeared in the welded seams of the pipe supports, significantly reducing the system's stability and utilization rate. Utility Model Content

[0005] The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a modification structure for improving the efficiency and reducing noise of the inlet pipe of a seawater desalination flash evaporator. This modification structure solves the technical problems of low flash evaporation efficiency, small water treatment capacity, excessive pressure difference, serious vibration and noise, and difficulty in implementing large-diameter modifications in confined spaces, without altering the main body of the flash evaporator or extending the downtime.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A structure for improving efficiency and reducing noise in the inlet pipe of a seawater desalination flash evaporator includes: The flash chamber has a water inlet side and a DN700 hot water inlet; A water inlet pipe extends into and out of the DN700 hot water inlet to the water inlet side of the flash chamber; A prefabricated spray water distribution assembly is installed inside the flash evaporator and connected to the water inlet pipe. The prefabricated spray water distribution assembly is prefabricated outside the flash evaporator and includes a main spray pipe and spray branch pipes connected to the main spray pipe. Both the main spray pipe and the spray branch pipes are equipped with nozzles. The flash evaporation flow hole is opened on the water inlet side of the flash chamber, and there is no baffle on the outer wall of the water inlet side of the flash chamber. Water is distributed into the flash chamber by the prefabricated spray water distribution assembly.

[0007] Preferably, there are five spray branch pipes, each of which is equipped with two branch pipe nozzles, and the main spray pipe is equipped with eight main pipe nozzles.

[0008] Preferably, the flow rate of a single nozzle on the branch pipe of the spray branch pipe is 20 m³ / h, and the flow rate of a single nozzle on the main pipe of the spray main pipe is 50 m³ / h.

[0009] Preferably, the side wall of the flash chamber is provided with a manhole, the size of which is 730mm×480mm. The water inlet pipe and the prefabricated spray water distribution assembly are adapted to the manhole and are fed into the flash chamber through the DN700 hot water inlet. The maximum nominal diameter of the water inlet pipe and the prefabricated spray water distribution assembly does not exceed DN450 and the length is less than 1000mm.

[0010] Preferably, a stainless steel clamp is provided on the outside of the main spray pipe, which limits and fixes the spray branch pipe to the outside of the main spray pipe; the nozzle of the main pipe is fixed by the stainless steel clamp.

[0011] Preferably, the water inlet pipe, the main spray pipe, the branch spray pipe, the nozzle, and the clamp are all made of 316L stainless steel, and all welds are pickled and passivated.

[0012] Preferably, the flash flow hole includes: a rectangular steam flow hole disposed on the side wall of the flash chamber, mainly used for steam flow; and a strip-shaped reflux hole disposed at the bottom of the side wall of the flash chamber.

[0013] The flash flow holes are used to balance the inlet water flow and eliminate eddies.

[0014] Compared with the prior art, the present invention has the following beneficial effects: Significantly increased water treatment capacity: Water is introduced into a large-diameter water distribution component through a DN700 hot water inlet, and water is distributed by a combination of a main spray pipe and multiple branch spray pipes. The water treatment capacity of a single unit has been steadily increased from the original 60t / h to 70t / h to 100t / h, which significantly improves the water treatment capacity of a single unit.

[0015] Flash evaporation efficiency is significantly improved: the prefabricated spray water distribution assembly is prefabricated as a whole outside the flash chamber, and only a small amount of welding is required on site for rapid installation; the nozzles on the spray main pipe and spray branch pipe are arranged in zones, so that hot water is evenly distributed and fully flashed in the flash chamber, and the secondary steam production is increased.

[0016] Significant noise and vibration reduction effects: The original solid baffle plate was removed and replaced with a flash flow hole on the water inlet side of the flash chamber, which eliminated the severe impact of water flow on the solid plate and the eddy current behind the plate. The equipment vibration and operating noise were significantly reduced, and the operation was more stable.

[0017] Pressure differential returns to normal: turbulence in the flow field is eliminated, the pressure differential between the flash chamber and the first-effect evaporation chamber is reduced to the reasonable design range, and the system's operational stability is enhanced.

[0018] Convenient and safe construction: The existing DN700 hot water inlet is fully utilized as a large-diameter channel. Combined with the precise adaptation of the manhole size, the modification can be completed without extending the downtime. All components are made of 316L stainless steel and have undergone pickling and passivation treatment, which effectively resists high-temperature seawater corrosion and extends the service life of the equipment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a flash chamber in the prior art; Figure 2 This is a schematic diagram of the installation of the modified structure described in an embodiment of this utility model; Figure 3 This is a schematic diagram of the prefabricated spray water distribution assembly described in an embodiment of the present invention; Figure 4 This is a top view of the prefabricated spray water distribution assembly described in an embodiment of the present invention.

[0020] In the diagram: 1. DN700 hot water inlet; 2. Outer wall of the flash chamber on the water inlet side; 3. Baffle plate; 4. Flash chamber; 5. Water inlet pipe; 6. Flash flow hole; 7. Spray branch pipe; 8. Stainless steel clamp; 9. Branch pipe nozzle; 10. Spray main pipe; 11. Main pipe nozzle. Detailed Implementation

[0021] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, in the prior art, the flash chamber 4 typically relies on a bottom water inlet channel for water to enter from bottom to top. After the water flow impacts the solid baffle 3 set on the outer wall 2 of the water inlet side of the flash chamber, it enters the interior of the flash chamber 4 through the overflow holes on the baffle 3 to complete the water distribution. This method results in uneven water distribution and violent impact, and conventional modification methods make it difficult to send a large-diameter water distribution device into the interior.

[0023] This embodiment provides a structure for improving the efficiency and reducing noise of the inlet pipe of a seawater desalination flash evaporator. For example... Figures 2 to 4 As shown, the flash chamber 4 has a DN700 hot water inlet 1 and a manhole located on the side wall. The water inlet pipe 5 extends into and to the water inlet side of the flash chamber 4 through the DN700 hot water inlet 1. The diameter and length of the water inlet pipe 5 are adapted to the manhole restrictions, and the maximum nominal diameter of the pipe does not exceed DN450 and the length is less than 1000mm.

[0024] The prefabricated spray water distribution assembly is installed inside the flash chamber 4 and connected to the inlet pipe 5. This prefabricated assembly is entirely prefabricated outside the flash chamber 4, requiring only minor welding for on-site installation. The prefabricated spray water distribution assembly includes a main spray pipe 10 and five branch spray pipes 7 connected to it. The main spray pipe 10 is located at the top of the inlet pipe 5 and on the outer side of the water inlet side outer wall 2 of the flash chamber. The main spray pipe 10 has eight main pipe nozzles 11, and each branch spray pipe 7 has two branch pipe nozzles 9. The flow rate of a single branch pipe nozzle 9 is 20 m³ / h, and the flow rate of a single main pipe nozzle 11 is 50 m³ / h. Stainless steel clamps 8 are installed on the outside of the main spray pipe 10 to limit and fix the branch spray pipes 7 to the outside of the main spray pipe 10, ensuring uniform spacing between spray layers. Both the branch pipe nozzle 9 and the main pipe nozzle 11 are fixed by stainless steel clamps 8. The nozzles (including the branch pipe nozzle 9 and the main pipe nozzle 11) face the interior space of the flash chamber 4 to achieve uniform spraying and water distribution.

[0025] The original solid baffle plate 3 on the outer wall of the flash chamber 4 on the water inlet side is removed, and the baffle plate is no longer installed. Instead, a flash flow hole 6 is opened on the water inlet side. The flash flow hole 6 includes: a rectangular steam flow hole 61, which is set on the side wall of the flash chamber and is mainly used for steam flow; and a strip-shaped return hole 62, which is set at the bottom of the side wall of the flash chamber 4. The flash flow hole 6 is used to balance the water inlet flow and eliminate eddies, reducing vibration and noise caused by water flow impact.

[0026] All components, including the water inlet pipe 5, the main spray pipe 10, the branch spray pipe 7, the branch pipe nozzles 9, the main pipe nozzles 11, and the stainless steel clamps 8, are made of 316L austenitic stainless steel. After all welding processes are completed, the entire weld seam is pickled and passivated to resist pitting and crevice corrosion in the high-temperature seawater environment and extend the service life of the equipment.

[0027] After the modification, high-temperature hot water is delivered from the DN700 hot water inlet 1 through the inlet pipe 5 to the prefabricated spray distribution assembly on the inlet side of the flash chamber 4. It is then evenly distributed to each spray branch pipe 7 via the main spray pipe 10, and finally sprayed into the interior space of the flash chamber 4 by the branch pipe nozzles 9 and the main pipe nozzles 11. Compared with before the modification, the water processing capacity of a single unit has steadily increased from 60t / h to 70t / h to 100t / h. Equipment vibration and operating noise have been significantly reduced, the pressure difference between the flash chamber 4 and the first-effect evaporation chamber has returned to the reasonable design range, and both flash evaporation efficiency and system stability have been significantly improved.

Claims

1. A structure for improving efficiency and reducing noise in the inlet pipe of a seawater desalination flash evaporator, characterized in that, include: Flash chamber (4), the flash chamber (4) having a water inlet side and a DN700 hot water inlet (1); Water inlet pipe (5), which extends into and out of the DN700 hot water inlet (1) to the water inlet side of the flash chamber (4); A prefabricated spray water distribution assembly is installed inside the flash chamber (4) and connected to the water inlet pipe (5). The prefabricated spray water distribution assembly is prefabricated outside the flash chamber (4) and includes a main spray pipe (10) and a branch spray pipe (7) connected to the main spray pipe (10). Both the main spray pipe (10) and the branch spray pipe (7) are equipped with nozzles. Flash flow hole (6) is opened on the water inlet side of the flash chamber (4), and the prefabricated spray water distribution assembly distributes water into the flash chamber (4).

2. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 1, characterized in that, The spray branch pipe (7) is provided with five branches, each of which is provided with two branch pipe nozzles (9), and the spray main pipe (10) is provided with eight main pipe nozzles (11).

3. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 2, characterized in that, The flow rate of a single branch nozzle (9) is 20 m³ / h, and the flow rate of a single main nozzle (11) is 50 m³ / h.

4. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 1, characterized in that, The flash chamber (4) has a manhole on its side wall. The size of the manhole is 730mm×480mm. The water inlet pipe (5) and the prefabricated spray water distribution assembly are adapted to the manhole and are sent into the flash chamber (4) through the DN700 hot water inlet (1). The maximum nominal diameter of the water inlet pipe (5) and the prefabricated spray water distribution assembly does not exceed DN450 and the length is less than 1000mm.

5. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 1, characterized in that, The main spray pipe (10) is provided with a stainless steel clamp (8) on the outside. The stainless steel clamp (8) limits and fixes the spray branch pipe (7) to the outside of the main spray pipe (10). The nozzle is fixed by the stainless steel clamp (8).

6. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 5, characterized in that, The water inlet pipe (5), the main spray pipe (10), the branch spray pipe (7), the nozzle and the clamp are all made of 316L stainless steel, and all welds are pickled and passivated.

7. The efficiency-enhancing and noise-reducing modification structure for the inlet pipe of a seawater desalination flash evaporator according to claim 1, characterized in that, The flash flow hole (6) includes: a rectangular steam flow hole (61) disposed on the side wall of the flash chamber (4) and mainly used for steam flow; and a strip-shaped reflux hole (62) disposed at the bottom of the side wall of the flash chamber (4).

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