Alumina evaporation system

Abstract

The utility model relates to the technical field of aluminum oxide production, in particular to an aluminum oxide evaporation system, which comprises a first evaporator module, a second evaporator module, a third evaporator module, a first flash evaporator module, a second flash evaporator module, a stock solution tank and a blending tank, the first flash evaporator module is connected with the first evaporator module, and the stock solution tank is respectively connected with the second evaporator module and the blending tank, so that a stock solution sequentially passes through the second evaporator module, the first evaporator module and the first flash evaporator module to be evaporated and concentrated to obtain a first mother solution; the third evaporator module is connected with the second flash evaporator module and the stock solution tank in sequence, so that the stock solution is evaporated and concentrated through the second flash evaporator module and the third evaporator module in sequence to obtain a second mother solution. The mother liquor concentration can be conveniently adjusted, and fluctuation of the mother liquor concentration is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of aluminum oxide production, in particular to an aluminum oxide evaporation system. Technical Field

[0003] Aluminum oxide is an inorganic substance with the chemical formula Al2O3. It is a high-hardness compound with a melting point of 2054℃ and a boiling point of 2980℃. It is an ion crystal that can be ionized at high temperatures and is often used to make refractory materials. With the rapid development of my country's electrolytic aluminum, ceramics, medicine, electronics, machinery and other industries, the market demand for alumina still has a large room for growth, and the output of alumina will continue to grow.

[0004] In the production of alumina, it is necessary to evaporate and concentrate the Bayer process seed liquor or the sintering process carbon liquor, discharge excess salt, obtain qualified circulating mother liquor, and then apply it to the next cycle. The evaporation process currently used in alumina production is multi-effect evaporation, which uses steam as a heat source to concentrate the evaporated stock solution. Due to the long evaporation process, it will take a long time for the adjustment of parameters to be reflected in the changes in the outlet mother liquor concentration. The process parameter operation is blind, resulting in large fluctuations in the outlet mother liquor concentration, and even unqualified situations, resulting in a large consumption of steam. Utility Model Content

[0005] In order to solve the above problems, the utility model provides an aluminum oxide evaporation system, which can facilitate the adjustment of the mother liquor concentration and reduce the fluctuation of the mother liquor concentration.

[0006] In order to achieve the above purpose, the technical solution of the utility model is:

[0007] An aluminum oxide evaporation system comprises a first evaporator module, a second evaporator module, a third evaporator module, a first flash evaporator module, a second flash evaporator module, a raw liquid tank and a mixing tank.

[0008] The first evaporator module, the second evaporator module, and the third evaporator module are connected in sequence, the first flash evaporator module is connected to the first evaporator module, and the stock liquid tank is connected to the second evaporator module and the mixing tank respectively, so that the stock liquid is evaporated and concentrated through the second evaporator module, the first evaporator module, and the first flash evaporator module in sequence to obtain a first mother liquid, and the first mother liquid enters the mixing tank;

[0009] The third evaporator module is connected to the second flash evaporator module and the raw liquid tank in sequence, so that the raw liquid is evaporated and concentrated through the second flash evaporator module and the third evaporator module in sequence to obtain a second mother liquid, and the second mother liquid enters the mixing tank.

[0010] Further, the first evaporator module includes a first effect evaporator and a second effect evaporator, the second evaporator module includes a third effect evaporator and a fourth effect evaporator, and the third evaporator module includes a fifth effect evaporator and a sixth effect evaporator.

[0011] The first effect evaporator, the second effect evaporator, the third effect evaporator, the fourth effect evaporator, the fifth effect evaporator, and the sixth effect evaporator are connected in sequence through a steam pipe, so that new steam passes through the first effect evaporator, the second effect evaporator, the third effect evaporator, the fourth effect evaporator, the fifth effect evaporator, and the sixth effect evaporator in sequence;

[0012] The first effect evaporator, the second effect evaporator, the third effect evaporator, the fourth effect evaporator, the fifth effect evaporator, and the sixth effect evaporator are correspondingly provided with condensed water tanks, and the condensed water tanks are connected in sequence so that the condensed water of the first effect evaporator, the second effect evaporator, the third effect evaporator, the fourth effect evaporator, the fifth effect evaporator, and the sixth effect evaporator are collected in a water tank.

[0013] Furthermore, the condensed water tank of the first effect evaporator is connected to a plate heat exchanger.

[0014] Further, the first flash evaporator module comprises a first flash evaporator, a second flash evaporator and a third flash evaporator connected in sequence, and the third flash evaporator is connected to the mixing tank, so that the raw liquid is sequentially evaporated and concentrated through the fourth effect evaporator, the third effect evaporator, the second effect evaporator, the first effect evaporator, the first flash evaporator, the second flash evaporator and the third flash evaporator to obtain a first mother liquid, and the first mother liquid enters the mixing tank;

[0015] The steam from the first flash evaporator is input to the second effect evaporator, the steam from the second flash evaporator is input to the third effect evaporator, and the steam from the third flash evaporator is input to the fourth effect evaporator.

[0016] Further, the second flash evaporator module includes a first stock liquid flash evaporator and a second stock liquid flash evaporator, the first stock liquid flash evaporator, the second stock liquid flash evaporator, the VI effect evaporator, and the V effect evaporator are connected in sequence, and the V effect evaporator is connected to the mixing tank, so that the stock liquid is evaporated and concentrated through the first stock liquid flash evaporator, the second stock liquid flash evaporator, the VI effect evaporator, and the V effect evaporator in sequence to obtain a second mother liquid, and the second mother liquid enters the mixing tank.

[0017] Furthermore, it also includes a water cooler, and the water vapor from the first raw liquid flash evaporator, the second raw liquid flash evaporator and the VI-effect evaporator is introduced into the water cooler.

[0018] Furthermore, it also includes a forced effect evaporator, the new steam and the steam of the first effect evaporator are passed into the forced effect evaporator to provide heat for the discharge of the forced effect evaporator, and the forced effect evaporator is provided with a forced effect condensation water tank, and the condensation water of the forced effect condensation water tank is passed into the condensation water tank of the VI effect evaporator.

[0019] The beneficial effects of the utility model are:

[0020] The first evaporator module, the second evaporator module, and the third evaporator module are connected in sequence, and multiple evaporators can be connected in series to form a multi-stage evaporation system. The previous stage evaporator serves as the heating steam for the next stage evaporator, thereby realizing the step-by-step utilization of energy, so that the raw liquid is evaporated and concentrated after passing through the second evaporator module, the first evaporator module, and the first flash evaporator module to obtain the first mother liquor, and the raw liquid is evaporated and concentrated after passing through the second flash evaporator module and the third evaporator module in sequence to obtain the second mother liquor with a different concentration from the first mother liquor. The first mother liquor and the second mother liquor are blended through the blending tank to stably obtain the mother liquor of the required concentration, thereby providing sufficient circulating mother liquor with a qualified concentration for the next process of raw material grinding. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural block diagram of an alumina evaporation system in a preferred embodiment of the utility model.

[0022] In the figure, 1-first effect evaporator, 12-second effect evaporator, 13-third effect evaporator, 14-fourth effect evaporator, 15-fifth effect evaporator, 16-VI effect evaporator, 17-condensate tank, 18-plate heat exchanger, 21-first flash evaporator, 22-second flash evaporator, 23-third flash evaporator, 31-first raw liquid flash evaporator, 32-second raw liquid flash evaporator, 4-raw liquid tank, 5-preparation tank, 6-water tank, 7-water cooler, 8-forced effect evaporator, 81-forced effect condensate tank. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a component centered. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a component centered. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a component centered. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0026] See also Figure 1 An alumina evaporation system according to a preferred embodiment of the present invention includes a first evaporator module, a second evaporator module, a third evaporator module, a first flash evaporator module, a second flash evaporator module, a raw liquid tank 4 and a mixing tank 5.

[0027] The first evaporator module, the second evaporator module, and the third evaporator module are connected in sequence, the first flash evaporator module is connected to the first evaporator module, and the raw liquid tank 4 is respectively connected to the second evaporator module and the mixing tank 5, so that the raw liquid is evaporated and concentrated through the second evaporator module, the first evaporator module, and the first flash evaporator module in sequence to obtain a first mother liquid, and the first mother liquid enters the mixing tank 5.

[0028] The third evaporator module is connected to the second flash evaporator module and the raw liquid tank 4 in sequence, so that the raw liquid is evaporated and concentrated through the second flash evaporator module and the third evaporator module in sequence to obtain a second mother liquid, and the second mother liquid enters the mixing tank 5.

[0029] The first evaporator module, the second evaporator module, and the third evaporator module are connected in sequence, and multiple evaporators can be connected in series to form a multi-stage evaporation system. The previous stage evaporator serves as the heating steam for the next stage evaporator, thereby realizing the step-by-step utilization of energy, so that the raw liquid is evaporated and concentrated after passing through the second evaporator module, the first evaporator module, and the first flash evaporator module to obtain a first mother liquor, and the raw liquid is evaporated and concentrated after passing through the second flash evaporator module and the third evaporator module in sequence to obtain a second mother liquor with a different concentration from the first mother liquor. The first mother liquor and the second mother liquor are blended by the blending tank 5 to stably obtain the mother liquor of the required concentration, thereby providing sufficient circulating mother liquor with a qualified concentration for the next step of raw material grinding.

[0030] In this embodiment, the first evaporator module includes a first effect evaporator 11 and a second effect evaporator 12, the second evaporator module includes a third effect evaporator 13 and a fourth effect evaporator 14, and the third evaporator module includes a fifth effect evaporator 15 and a sixth effect evaporator 16.

[0031] The first effect evaporator 11, the second effect evaporator 12, the third effect evaporator 13, the fourth effect evaporator 14, the fifth effect evaporator 15, and the sixth effect evaporator 16 are connected in sequence through steam pipes so that new steam passes through the first effect evaporator 11, the second effect evaporator 12, the third effect evaporator 13, the fourth effect evaporator 14, the fifth effect evaporator 15, and the sixth effect evaporator 16 in sequence.

[0032] The first effect evaporator 11, the second effect evaporator 12, the third effect evaporator 13, the fourth effect evaporator 14, the fifth effect evaporator 15, and the sixth effect evaporator 16 are correspondingly provided with condensed water tanks 17, and each condensed water tank 17 is connected in sequence so that the condensed water of the first effect evaporator 11, the second effect evaporator 12, the third effect evaporator 13, the fourth effect evaporator 14, the fifth effect evaporator 15, and the sixth effect evaporator 16 are collected in the water tank 6.

[0033] In this embodiment, the condensate tank 17 of the first-effect evaporator 11 is connected to the plate heat exchanger 18. The primary steam condensate produced by the first-effect evaporator 11 can be supplied to the thermal power plant or sent to the condensate tank of this workshop for storage through the plate heat exchanger 18 according to its alkalinity or production requirements.

[0034] The first flash evaporator module includes a first flash evaporator 21, a second flash evaporator 22 and a third flash evaporator 23 which are connected in sequence, and the third flash evaporator 23 is connected to the mixing tank 5, so that the raw liquid is evaporated and concentrated in sequence through the fourth effect evaporator 14, the third effect evaporator 13, the second effect evaporator 12, the first effect evaporator 11, the first flash evaporator 21, the second flash evaporator 22 and the third flash evaporator 23 to obtain a first mother liquor, and the first mother liquor enters the mixing tank 5.

[0035] The steam from the first flash evaporator 21 is input to the second effect evaporator 12, the steam from the second flash evaporator 22 is input to the third effect evaporator 13, and the steam from the third flash evaporator 23 is input to the fourth effect evaporator 14. The water molecules in the raw liquid are evaporated by using a multi-stage flash evaporator to achieve evaporation and concentration of the raw liquid.

[0036] In this embodiment, the second flash evaporator module includes a first raw liquid flash evaporator 31 and a second raw liquid flash evaporator 32. The first raw liquid flash evaporator 31, the second raw liquid flash evaporator 32, the VI effect evaporator 16, and the V effect evaporator 15 are connected in sequence, and the V effect evaporator 15 is connected to the mixing tank 5, so that the raw liquid passes through the first raw liquid flash evaporator 31, the second raw liquid flash evaporator 32, the VI effect evaporator 16, and the V effect evaporator 15 in sequence to be evaporated and concentrated to obtain a second mother liquid, and the second mother liquid enters the mixing tank 5.

[0037] In this embodiment, a water cooler 7 is further included, and the water vapor of the first raw liquid flash evaporator 31, the second raw liquid flash evaporator 32 and the VI effect evaporator 16 is passed into the water cooler 7. The secondary steam generated by the VI effect evaporator 16 is passed into the water cooler 7 to ensure that the evaporation system maintains a certain vacuum degree. The water cooler 7 of this embodiment is provided with a vacuum pump to obtain circulating upper water and circulating lower water.

[0038] This embodiment also includes a forced high-efficiency evaporator 8, and the new steam and the steam of the first-effect evaporator 11 are introduced into the forced high-efficiency evaporator 8 to provide heat for the discharge of the forced high-efficiency evaporator 8, and the forced high-efficiency evaporator 8 is provided with a forced high-efficiency condensed water tank 81, and the condensed water of the forced high-efficiency condensed water tank 81 is introduced into the condensed water tank 17 of the sixth-effect evaporator 16. Preferably, a certain flow of evaporation mother liquor is introduced from the third-effect flash evaporator 23 to the forced high-efficiency evaporator 8 for super-concentration treatment, and at the same time, salt slurry is added to the forced high-efficiency evaporator 8 as a seed crystal to make Na2CO3 in the solution crystallize out quickly; the salt sedimentation tank of the discharge of the forced high-efficiency evaporator 8, after the salt is discharged by the salt discharge system, the strong alkali solution returns to the third-effect flash evaporator 23, is sent to the blending tank or is supplied to various alkali points in the whole plant, and the Na2CO3 salt is dissolved by heated water and causticized by lime milk, and the causticized dilute liquid is sent to the blending tank, and the causticized slag is sent to the sedimentation leaf filter.

[0039] In this embodiment, the condensed water generated by the II effect evaporator 12, the III effect evaporator 13, the IV effect evaporator 14, the V effect evaporator 15, and the VI effect evaporator 16 is subjected to the effect of pressure difference, so that the condensed water enters the water tank from the condensed water tanks 17 corresponding to the II effect evaporator 12, the III effect evaporator 13, the IV effect evaporator 14, the V effect evaporator 15, and the VI effect evaporator 16; the condensed water generated by the forced high effect evaporator 8 enters the condensed water tank 17 of the VI effect evaporator 16 under the effect of pressure difference, and is sent to the water tank through the secondary steam condensed water pump.

[0040] In this embodiment, the new steam pressure is 5.0-6.0 bar, the temperature is 170±20°C; the evaporation raw liquid temperature is ≥85°C; the steam consumption is 0.273t / t·H2O; the evaporation mother liquid concentration NK is 235-255g / l; the forced effect discharge concentration NK is 300-320g / l; the VI effect liquid temperature is controlled at 54-56°C; the circulating upper water temperature is ≤30°C, and the circulating lower water temperature is ≤50°C.

[0041] The raw liquid treatment process of the alumina evaporation system of this embodiment is as follows:

[0042] The raw liquid is divided into two parts for processing. One part of the raw liquid is sequentially evaporated and concentrated through the IV effect evaporator 14, the III effect evaporator 13, the II effect evaporator 12, the I effect evaporator 11, the I flash evaporator 21, the II flash evaporator 22, and the III flash evaporator 23 to obtain a first mother liquid, and the first mother liquid enters the mixing tank 5; the other part of the raw liquid is sequentially evaporated and concentrated through the first raw liquid flash evaporator 31, the second raw liquid flash evaporator 32, the VI effect evaporator 16, and the V effect evaporator 15 to obtain a second mother liquid, and the second mother liquid enters the mixing tank 5.

Claims

1. An alumina evaporation system, characterized in that: It comprises a first evaporator module, a second evaporator module, a third evaporator module, a first flash evaporator module, a second flash evaporator module, a raw liquid tank (4) and a mixing tank (5), The first evaporator module, the second evaporator module, and the third evaporator module are connected in sequence, the first flash evaporator module is connected to the first evaporator module, and the stock liquid tank (4) is connected to the second evaporator module and the mixing tank (5) respectively, so that the stock liquid is evaporated and concentrated through the second evaporator module, the first evaporator module, and the first flash evaporator module in sequence to obtain a first mother liquid, and the first mother liquid enters the mixing tank (5); The third evaporator module is connected to the second flash evaporator module and the raw liquid tank (4) in sequence, so that the raw liquid is evaporated and concentrated through the second flash evaporator module and the third evaporator module in sequence to obtain a second mother liquid, and the second mother liquid enters the mixing tank (5).

2. An aluminum oxide evaporation system according to claim 1, characterized in that: The first evaporator module comprises a first effect evaporator (11) and a second effect evaporator (12), the second evaporator module comprises a third effect evaporator (13) and a fourth effect evaporator (14), and the third evaporator module comprises a fifth effect evaporator (15) and a sixth effect evaporator (16). The first effect evaporator (11), the second effect evaporator (12), the third effect evaporator (13), the fourth effect evaporator (14), the fifth effect evaporator (15), and the sixth effect evaporator (16) are connected in sequence through a steam pipe, so that new steam passes through the first effect evaporator (11), the second effect evaporator (12), the third effect evaporator (13), the fourth effect evaporator (14), the fifth effect evaporator (15), and the sixth effect evaporator (16) in sequence; The first effect evaporator (11), the second effect evaporator (12), the third effect evaporator (13), the fourth effect evaporator (14), the fifth effect evaporator (15), and the sixth effect evaporator (16) are respectively provided with condensed water tanks (17), and the condensed water tanks (17) are connected in sequence so that the condensed water of the first effect evaporator (11), the second effect evaporator (12), the third effect evaporator (13), the fourth effect evaporator (14), the fifth effect evaporator (15), and the sixth effect evaporator (16) are collected in a water tank (6).

3. An aluminum oxide evaporation system according to claim 2, characterized in that: The condensed water tank (17) of the first-effect evaporator (11) is connected to a plate heat exchanger (18).

4. An aluminum oxide evaporation system according to claim 2, characterized in that: The first flash evaporator module comprises a first flash evaporator (21), a second flash evaporator (22) and a third flash evaporator (23) which are connected in sequence, and the third flash evaporator (23) is connected to the mixing tank (5), so that the raw liquid passes through the fourth effect evaporator (14), the third effect evaporator (13), the second effect evaporator (12), the first effect evaporator (11), the first flash evaporator (21), the second flash evaporator (22) and the third flash evaporator (23) in sequence for evaporation and concentration to obtain a first mother liquid, and the first mother liquid enters the mixing tank (5); The steam from the first flash evaporator (21) is input to the second effect evaporator (12), the steam from the second flash evaporator (22) is input to the third effect evaporator (13), and the steam from the third flash evaporator (23) is input to the fourth effect evaporator (14).

5. The aluminum oxide evaporation system according to claim 2, characterized in that: The second flash evaporator module comprises a first raw liquid flash evaporator (31) and a second raw liquid flash evaporator (32); the first raw liquid flash evaporator (31), the second raw liquid flash evaporator (32), the VI-effect evaporator (16), and the V-effect evaporator (15) are connected in sequence, and the V-effect evaporator (15) is connected to the mixing tank (5), so that the raw liquid is evaporated and concentrated in sequence through the first raw liquid flash evaporator (31), the second raw liquid flash evaporator (32), the VI-effect evaporator (16), and the V-effect evaporator (15) to obtain a second mother liquid, and the second mother liquid enters the mixing tank (5).

6. An aluminum oxide evaporation system according to claim 5, characterized in that: It also includes a water cooler (7), into which water vapor from the first raw liquid flash evaporator (31), the second raw liquid flash evaporator (32) and the VI-effect evaporator (16) is introduced.

7. An aluminum oxide evaporation system according to claim 5, characterized in that: The invention also comprises a forced effect evaporator (8), wherein the new steam and the steam of the first effect evaporator (11) are passed into the forced effect evaporator (8) to provide heat for the discharge of the forced effect evaporator (8), and the forced effect evaporator (8) is provided with a forced effect condensate tank (81), and the condensate of the forced effect condensate tank (81) is passed into the condensate tank (17) of the sixth effect evaporator (16).

Images