Large phosphoric acid flash cooling evaporator

Abstract

The utility model discloses a large-scale phosphoric acid flash cooling evaporator, which solves the problems that the existing evaporator is poorer in abrasion resistance, short in service life and difficult to maintain, and adopts the technical scheme that the large-scale phosphoric acid flash cooling evaporator comprises an upper sealing head, an upper-section barrel body, a lower-section barrel body and a lower cone, a rubber lining covers the inner surface of the upper-section barrel body, and alloy coatings cover the inner surfaces of the lower-section barrel body and the lower cone. The lower end of the rubber lining at the junction of the upper-section barrel body and the lower-section barrel body is pressed on the surface of the upper end of the alloy coating, a pressing plate is arranged outside the lower end of the rubber lining, the lower end of the pressing plate is pressed on the alloy coating, and the upper end of the pressing plate is pressed on the rubber lining; the lower ends of a plurality of alloy bolts are welded on the alloy coating at the junction, and the upper ends of the alloy bolts sequentially penetrate through the rubber lining and the pressing plate to be connected and tightened with the alloy nuts. The heat exchanger is simple in structure, long in service life, easy to maintain and good in heat transfer effect, and the whole heat exchanger is wear-resistant and corrosion-resistant.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of evaporators. BACKGROUND

[0002] Flash evaporator is the key equipment in wet-process phosphoric acid plant, its principle is to make liquid evaporation to take away heat under the operating condition close to vacuum, to remove the reaction heat of phosphoric acid reaction slurry, balance the operating temperature of reaction tank.

[0003] Traditional flash evaporator is conical bottom structure, reaction slurry is pumped from the wall of the equipment and enters axially. The cylinder is made of steel lined rubber structure, and the lower cylinder is lined with carbon bricks, which can be suitable for certain abrasion of reaction slurry. But the conical bottom is severely eroded due to high flow rate and scouring, even if it is made of steel lined rubber and brick structure, the service life is not long, and it needs to be replaced and repaired many times every year, which affects the continuous operation of the whole device.

[0004] For example, the publication number 203886214U discloses a phosphoric acid slurry flash evaporator, which includes a cylinder and a top cover. The cylinder is provided with a material inlet and a material outlet, and the top cover is provided with an exhaust port. The top cover is a single-layer glass steel, and the outer surface of the top cover is provided with a reinforcing rib. The improved phosphoric acid slurry flash evaporator effectively improves the corrosion resistance of the equipment during production, enhances the compressive strength, reduces the downtime for equipment maintenance, and improves the production efficiency. The structure of the top cover is improved to solve the problem of corrosion and pressure resistance at the top, but the problem of abrasion of the lower cylinder and the conical bottom is not solved. SUMMARY

[0005] The utility model aims at solving the above technical problem, and provides a large-scale phosphoric acid flash evaporator with simple structure, overall abrasion resistance, long service life, easy maintenance and good heat transfer effect.

[0006] The technical scheme includes an upper head, an upper cylinder, a lower cylinder and a lower cone. The inner surface of the upper cylinder is covered with a rubber lining, and the inner surfaces of the lower cylinder and the lower cone are covered with an alloy cladding layer. The lower end of the rubber lining at the junction of the upper and lower cylinders is pressed onto the upper end surface of the alloy cladding layer. The lower end of the rubber lining is provided with a pressing plate. The lower end of the pressing plate is pressed onto the alloy cladding layer, and the upper end is pressed onto the rubber lining. The lower ends of a plurality of alloy bolts are welded to the alloy cladding layer at the junction, and the upper ends are connected to alloy nuts through the rubber lining and the pressing plate in sequence and tightened.

[0007] The lower end of the pressing plate is an arc edge.

[0008] The radius of the arc edge is the same as that of the lower cylinder.

[0009] The length L of the pressing plate covering the rubber lining is at least 80 mm.

[0010] The outer surface radius R1 of the pressing plate is smaller than the inner surface radius R2 of the rubber plate.

[0011] The alpha angle of the feed inlet on the lower section cylinder is 60-80 degrees.

[0012] The vertical distance between the center line of the feed inlet and the liquid level is 1.3-2 times the diameter of the feed inlet pipe.

[0013] The bottom of the lower cone has a vortex breaker at the discharge outlet.

[0014] In view of the problems in the background art, the inventors have made the following improvements:

[0015] In view of the problems in the background art, the inventors have made the following improvements:

[0016] The lower end of the rubber lining is provided with a pressing plate, which presses the end of the rubber lining. The lower end of the pressing plate is processed into an arc edge, which can avoid the slurry from washing the lower edge of the rubber lining, reduce the risk of slurry penetration and rubber lining warping and flanging. Preferably, the outer surface radius R1 of the pressing plate is smaller than the inner surface radius R2 of the rubber plate. In this way, after the alloy nut is tightened, the middle part of the pressing plate can also tightly press the rubber plate, further preventing the rubber plate from warping. The length L of the pressing plate covering the rubber lining is at least 80 mm to ensure sufficient coverage height.

[0017] Preferably, the feed inlet is a non-radial feed inlet, which has a certain spiral impact effect on the slurry, disturbs the slurry and promotes heat transfer. Preferably, the alpha angle of the feed inlet is 60-80 degrees. If it is greater than or equal to 80 degrees, the feed swirl is close to the cylinder wall and has a large friction with the cylinder wall. If it is less than or equal to 60 degrees, it is difficult to form an impact disturbance effect on the upper liquid surface. Preferably, the distance h between the center line of the feed inlet and the normal liquid level is 1.3-2 times the diameter of the feed inlet pipe, which can avoid the flash boiling phenomenon of the material and cause serious mist entrainment at the gas outlet. The bottom of the lower cone has a vortex breaker, such as a cross-shaped vortex breaker, which can reduce the swirl at the bottom of the lower cone, reduce the flow rate and reduce the abrasion of the lower cone.

[0018] The utility model discloses the structure is simple, and the material is applied, and it can not only meet the problem of liquid solid medium corrosion and strong abrasion, but also adapt to the problem of gas phase high fluorine medium corrosion, improve the service life of the equipment, be easy to maintain, reduce the alloy usage amount, and the cost is low, the flash evaporation amount is big, and the operation is stable under the negative pressure condition, and the effect of flow disturbance is good. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a schematic view of the utility model structure.

[0020] Figure 2 It is Figure 1 A-A view.

[0021] Figure 3 It is Figure 1 I node amplification view in.

[0022] Figure 4 It is Figure 3 B-B view.

[0023] 1-gas phase outlet, 2-upper head, 3-upper section cylinder, 4-feeding port, 5-lower section cylinder, 6-lower cone, 7-discharge port, 8-vortex breaker, 9-weld, 10-pressing plate, 10.1-arc edge, 11-bolt weld, 12-alloy nut, 13-alloy bolt, 14-rubber lining, 15-alloy cladding, M-rubber lining cutoff line, N-alloy cladding cutoff line. DETAILED DESCRIPTION

[0024] The utility model is further explained and described below in combination with the drawings:

[0025] Referring to Figure 1 , the utility model includes upper head 2, upper section cylinder 3, lower section cylinder 5 and lower cone 6, and the upper section cylinder 3 and lower section cylinder 5 are welded (with weld 9) between, the upper section cylinder 3 top is equipped with gas phase outlet 1, and the inner surface is covered rubber lining 14, and the inner surface of lower section cylinder 5 and lower cone 6 is covered alloy cladding 15, is equipped with feeding port 4 on lower section cylinder 5, referring to Figure 2 , the α angle of feeding port 4 is 60~80 °, and the vertical distance of the center line of feeding port 4 from liquid level is 1.3~2 times of the vertical distance of the center line of feeding port 4 from liquid level; lower cone 6 bottom is equipped with discharge port 7, and there is vortex breaker at discharge port 7.

[0026] Referring to Figure 3 , the lower end of rubber lining 14 at the junction of upper section cylinder 3 and lower section cylinder 5 is pressed on the upper end surface of alloy cladding 15, the lower end of rubber lining 14 is provided with pressing plate 10, the end of rubber lining is pressed by pressing plate, the lower end of pressing plate 10 is pressed on alloy cladding 15, and the upper end is pressed on rubber lining 14; the lower end of multiple alloy bolts 13 is welded on the alloy cladding 15 (with bolt weld 11) at the junction, and the upper end is sequentially connected and tightened with alloy nut 12 through rubber lining 14, pressing plate 10 and alloy nut 12.

[0027] The lower end of the pressing plate 10 is an arc edge 10.1, the curvature of which is the same as that of the lower section cylinder 5. The length L of the pressing plate 10 covered in the rubber lining 13 is at least 80 mm; see Figure 4 The outer surface radius R1 of the pressing plate 10 is smaller than the inner surface radius R2 of the rubber plate.

[0028] The upper section cylinder 3, the lower section cylinder 5 and the lower cone 6 are all made of carbon steel, and the alloy cladding layer 15 and the alloy bolt 13 and the alloy nut 12 can be made of nickel alloy material, super austenitic stainless steel material or duplex steel, such as Hastelloy, 3127hMo, 254smo, 904L, 2507, 2205, etc. Such materials can resist corrosion and abrasion of phosphoric acid slurry under high temperature working conditions.

Claims

1. A large phosphoric acid flash evaporator, comprising an upper head, an upper cylindrical section, a lower cylindrical section, and a lower cone, characterized in that, The upper section of the cylinder is covered with a rubber lining, and the lower section of the cylinder and the lower cone are covered with an alloy coating. The lower end of the rubber lining at the junction of the upper and lower sections of the cylinder is pressed onto the upper surface of the alloy coating. A pressure plate is provided on the lower end of the rubber lining. The lower end of the pressure plate is pressed onto the alloy coating, and the upper end is pressed onto the rubber lining. The lower ends of multiple alloy bolts are welded to the alloy coating at the junction, and the upper ends pass through the rubber lining, the pressure plate, and are connected and tightened with alloy nuts in sequence.

2. The large-scale phosphoric acid flash evaporator as described in claim 1, characterized in that, The lower end of the pressure plate has an arc edge.

3. The large-scale phosphoric acid flash evaporator as described in claim 2, characterized in that, The curvature of the arc edge is the same as that of the lower section of the cylinder.

4. The large-scale phosphoric acid flash evaporator as described in claim 1, characterized in that, The length L of the pressure plate covering the rubber lining is at least 80 mm.

5. The large-scale phosphoric acid flash evaporator as described in any one of claims 1-4, characterized in that, The outer surface radius R1 of the pressure plate is smaller than the inner surface radius R2 of the adhesive plate.

6. The large-scale phosphoric acid flash evaporator as described in any one of claims 1-4, characterized in that, The α angle of the feed inlet on the lower section of the cylinder is 60-80°.

7. The large-scale phosphoric acid flash evaporator as described in claim 6, characterized in that, The vertical distance between the centerline of the feed inlet and the liquid level above is 1.3 to 2 times the diameter of the feed inlet pipe.

8. The large-scale phosphoric acid flash evaporator as described in any one of claims 1-4, characterized in that, The discharge port at the bottom of the lower cone has a vortex breaker.

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