Condensation evaporator set for concentrating sodium aluminate solution

Abstract

The utility model discloses a condensation evaporator set for concentrating a sodium aluminate solution, and aims to solve the problems of higher production cost caused by more condensation water tank equipment of an evaporator set and higher steam consumption of the evaporator set caused by insufficient utilization of heat of secondary condensation water in the prior art. Comprising a steam condensation loop formed by sequentially connecting seven sets of evaporators, the steam condensation loop comprises a secondary steam condensation recovery branch, and the second-effect evaporator to the last-effect evaporator are directly and sequentially connected through a secondary condensate water collecting pipe. The secondary steam condensation recovery branch further comprises a secondary condensate water collecting tank and a secondary condensate water pump which are arranged on a secondary condensate water collecting pipe led out of the last-effect evaporator. The utility model has the advantages that a secondary condensate water tank corresponding to each effect heating chamber is omitted, the equipment investment of the secondary condensate water tank is reduced, the production cost is reduced, secondary condensate water directly enters the shell pass of the next effect heating chamber in sequence, the heat utilization is more sufficient, and the steam consumption of the evaporator group is lower.

Description

Technical Field

[0001] The utility model relates to the technical field of concentrated evaporation equipment for circulating mother liquor sodium aluminate solution in alumina production, in particular to a condenser evaporator group for concentrated sodium aluminate solution. Background Art

[0002] At present, in the production process of alumina, a six-effect evaporator group is usually used to concentrate and evaporate the sodium aluminate mother liquor. These evaporator groups have the problem of high steam consumption during operation, resulting in high production costs.

[0003] In the face of the above problems, a Chinese utility model patent with authorization announcement number CN212523051U and authorization announcement date of February 12, 2021 discloses a seven-effect segmented evaporator device. The seven-effect operation makes the secondary steam utilized six times, which makes the steam consumption lower when the solution is concentrated. However, in actual work, the secondary condensate drawn out from the second to seventh effect heating chambers respectively enter the corresponding secondary condensate tanks, and the secondary condensate tanks are connected in sequence, and finally enter the secondary condensate collection tank for combined collection. The condensate process is that the condensate from each effect heating chamber of the evaporator group enters its own condensate tank for collection, the primary condensate is collected by the primary condensate tank, and the secondary condensate tanks are connected in sequence and finally enter the last effect condensate tank for collection.

[0004] The defects of the above-mentioned evaporator group equipment are as follows: first, there are many devices in the condensate tank, many liquid level meters and regulating valves, resulting in high equipment investment and production costs; second, the heat of the secondary condensate is not fully utilized, and the steam consumption of the evaporator group is high. Utility Model Content

[0005] The utility model aims to provide a condenser evaporator group for concentrating sodium aluminate solution, so as to solve the problems of high equipment investment and production cost caused by more condensate tank equipment in the evaporator group in the prior art and high steam consumption of the evaporator group caused by insufficient utilization of heat of secondary condensed water.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] A condenser evaporator group for concentrating sodium aluminate solution is designed, including an evaporator consisting of a heating chamber and a vapor-liquid separation chamber, at least three-effect evaporators are connected in sequence to form a solution concentration circuit and a steam condensation circuit, the steam condensation circuit includes a primary steam condensation recovery branch and a secondary steam condensation recovery branch, the secondary steam condensation recovery branch includes a secondary condensate collection pipe, at least two adjacent evaporators of the effect are directly connected in sequence through the secondary condensate collection pipe, and the secondary steam condensation recovery branch also includes a secondary condensate collection tank on the secondary condensate collection pipe led out from the last-effect evaporator.

[0008] Preferably, the shell side of the heating chamber is connected to the secondary condensed water collecting pipe, and the shell side of the last-effect heating chamber is connected to the secondary condensed water collecting tank through the secondary condensed water collecting pipe.

[0009] Preferably, the heating chamber and the vapor-liquid separation chamber are split structures, and the seven-effect evaporators are connected in sequence to form a solution concentration loop and a steam circulation loop.

[0010] Preferably, the solution concentration circuit includes a first concentration branch and a second concentration branch arranged in parallel, the first concentration branch is composed of a V-effect evaporator, a IV-effect evaporator, a III-effect evaporator, a II-effect evaporator, an I-effect evaporator, a I-level flash evaporator, a II-level flash evaporator, a III-level flash evaporator, a IV-level flash evaporator, and a V-level flash evaporator connected in series in sequence, the feed port of the V-effect evaporator is connected to a raw liquid feed pipeline, and the discharge port of the V-effect flash evaporator is connected to a finished product recovery pipeline.

[0011] Preferably, the second concentration branch is composed of a VII effect evaporator and a VI effect evaporator connected in series in sequence, the feed port of the VII effect evaporator is connected to a raw liquid feed pipeline, and the discharge port of the VI effect evaporator is connected to a finished product recovery branch arranged on a finished product recovery pipeline.

[0012] Preferably, the primary steam condensation recovery branch includes an external raw steam inlet pipe connected to the steam inlet of the heating chamber of the first-effect evaporator and a primary condensate collecting pipe connected to the condensate outlet of the heating chamber of the first-effect evaporator, and the primary condensate collecting pipe is sequentially provided with a primary condensate collecting tank, a heat exchanger and a primary condensate pump.

[0013] Preferably, a circulating feeding pipeline is provided between the lower discharge port and the top feeding port of each effective heating chamber.

[0014] Compared with the prior art, the beneficial technical effects of the utility model are:

[0015] 1. The II-effect evaporator and the last-effect evaporator in the utility model are directly connected in sequence through the secondary condensed water collecting pipe, and the outlet of the last-effect heating chamber is connected with a secondary condensed water tank, which saves the secondary condensed water tanks corresponding to each effect heating chamber, and only uses one secondary condensed water tank to complete the collection of secondary condensed water, thereby reducing the investment in equipment such as secondary condensed water tanks, regulating valves, and automatic control, reducing the chance of equipment leakage in the evaporator group, and reducing production costs and maintenance costs.

[0016] 2. In the utility model, the secondary condensed water directly enters the shell side of the next-effect heating chamber in sequence, the heat of the secondary condensed water is more fully utilized, and the steam consumption of the evaporator group is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the utility model;

[0018] Figure 2 It is the material flow chart of the utility model;

[0019] Figure 3 This is a steam flow chart of the utility model.

[0020] In the figure, 1a-Ⅰ effect heating chamber; 1b-Ⅱ effect heating chamber; 1c-Ⅲ effect heating chamber; 1d-Ⅳ effect heating chamber; 1e-Ⅴ effect heating chamber; 1f-Ⅵ effect heating chamber; 1g-Ⅶ effect heating chamber; 2a-Ⅰ effect gas-liquid separation chamber; 2b-Ⅱ effect gas-liquid separation chamber; 2c-Ⅲ effect gas-liquid separation chamber; 2d-Ⅳ effect gas-liquid separation chamber; 2e-Ⅴ effect gas-liquid separation chamber; 2f-Ⅵ effect gas-liquid separation chamber; 2g-Ⅶ effect gas-liquid separation chamber; 3a-I-stage flash evaporator; 3b-II-stage flash evaporator; 3c-III-stage flash evaporator; 3d-IV-stage flash evaporator; 3e-V-stage flash evaporator; 4-raw liquid feeding pipeline; 5-finished product recovery pipeline; 6-circulating feeding pipeline; 7-circulating pump; 8-feeding pump; 9-external raw steam inlet pipeline; 10-water cooler; 11-vacuum pump; 12-primary condensate pump; 13-secondary condensate pump; 14-finished product feed pump; 15-first discharge pump; 17-heat exchanger; 18-primary condensate collection tank; 19-secondary condensate collection tank. DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is described below in conjunction with the accompanying drawings and embodiments, but the following embodiments are only used to illustrate the present invention in detail and do not limit the scope of the present invention in any way. The equipment parts, structures, etc. involved in the following embodiments are all conventional commercially available products unless otherwise specified.

[0022] Example 1: Figure 1-3 As shown, a condenser evaporator group for concentrating sodium aluminate solution includes an evaporator consisting of a heating chamber and a vapor-liquid separation chamber, and at least three-effect evaporators are connected in sequence to form a solution concentration circuit and a steam condensation circuit.

[0023] Specifically, the heating chamber and the gas-liquid separation chamber are split structures, and the seven-effect evaporator is connected in sequence to form a solution concentration loop and a steam circulation loop. The seven-effect evaporator includes an effect I evaporator (composed of an effect I heating chamber 1a and an effect I gas-liquid separation chamber 2a), an effect II evaporator (composed of an effect II heating chamber 1b and an effect II gas-liquid separation chamber 2b), and an effect III evaporator (composed of an effect III heating chamber 1c and an effect III gas-liquid separation chamber 2c); the low-temperature evaporator adopts a planar plate falling film evaporator, including an effect IV evaporator (composed of an effect IV heating chamber 1d and an effect IV gas-liquid separation chamber 2d), an effect V evaporator (composed of an effect V heating chamber 1e and an effect V gas-liquid separation chamber 2e), an effect VI evaporator (composed of an effect VI heating chamber 1f and an effect VI gas-liquid separation chamber 2f), and an effect VII evaporator (composed of an effect VII heating chamber 1g and an effect VII gas-liquid separation chamber 2g). The evaporator group further includes a flash evaporator, which includes a first-stage flash evaporator 3a, a second-stage flash evaporator 3b, a third-stage flash evaporator 3c, a fourth-stage flash evaporator 3d, and a fifth-stage flash evaporator 3e.

[0024] The solution concentration circuit includes a first concentration branch and a second concentration branch arranged in parallel, wherein the first concentration branch is composed of a V-effect evaporator, a IV-effect evaporator, a III-effect evaporator, a II-effect evaporator, an I-effect evaporator, a I-level flash evaporator, a II-level flash evaporator, a III-level flash evaporator, a IV-level flash evaporator, and a V-level flash evaporator connected in series in sequence, the feed port of the V-effect evaporator is connected to a raw liquid feed pipeline 4, and the discharge port of the V-level flash evaporator is connected to a finished product recovery pipeline 5; the second concentration branch is composed of a VII-effect evaporator and a VI-effect evaporator connected in series in sequence, the feed port of the VII-effect evaporator is connected to a raw liquid feed pipeline 4, and the discharge port of the VI-effect evaporator is connected to a finished product recovery branch pipe arranged on the finished product recovery pipeline 5.

[0025] A circulating feeding pipe 6 is arranged between the lower discharge port and the top feeding port of each effective heating chamber, and a circulating pump 7 is arranged on the circulating feeding pipe 6. A feeding pump 8 is installed on the material conveying pipe between each adjacent heating chamber in the first concentration branch and the second concentration branch systems.

[0026] The steam condensation circuit includes a primary steam condensation recovery branch and a secondary steam condensation recovery branch, wherein the primary steam condensation recovery branch includes an external raw steam inlet pipe 9 connected to the steam inlet of the I-effect heating chamber 1a and a primary condensate collecting pipe connected to the condensate outlet of the I-effect heating chamber 1a, and a primary condensate collecting tank 18, a heat exchanger 17 and a primary condensate pump 12 are installed on the primary condensate collecting pipe in sequence.

[0027] The secondary steam condensation recovery branch includes a secondary condensate collection pipe, and the II-VII effect evaporators are directly connected through the secondary condensate collection pipe. The secondary steam condensation recovery branch also includes a secondary condensate collection tank 19 and a secondary condensate pump 13 on the secondary condensate collection pipe led out from the VII effect evaporator, and also includes a secondary steam connecting pipe connecting the I-VII evaporators in sequence (that is, the secondary steam outlets of the I-III effect heating chambers are respectively connected to the corresponding gas-liquid separation chambers, and the secondary steam outlet pipelines of the I-VII effect gas-liquid separation chambers are respectively connected to the air inlets of the adjacent next effect heating chambers), secondary steam flash pipes connecting the I-V flash evaporators and the II-VI effect gas-liquid separation chambers respectively, and a non-condenser outlet pipe with a water cooler 10 and a vacuum pump 11 led out from the VII effect gas-liquid separation chamber 2g.

[0028] The shell sides of the above-mentioned II-VII effect heating chambers are connected in series via secondary condensate collecting pipes. The shell side outlet of the last effect heating chamber is connected to a secondary condensate tank, which eliminates the need for secondary condensate tanks corresponding to each effect heating chamber. The secondary condensate is collected by only one secondary condensate tank, thereby reducing the investment in equipment such as secondary condensate tanks and regulating valves, and reducing production costs. The secondary condensate directly enters the shell side of the next effect heating chamber in turn, so the heat of the secondary condensate is more fully utilized and the steam consumption of the evaporator group is lower.

[0029] During operation, the sodium aluminate solution enters the V-effect heating chamber 1e and the VII-effect heating chamber 1g respectively through the stock solution feed pipeline 4 according to the process of the two concentration branches: the stock solution entering the V-effect heating chamber 1e is connected to the IV-effect heating chamber 1d, the III-effect heating chamber 1c, the II-effect heating chamber 1b, and the I-effect heating chamber 1a for heating and evaporation, and then enters the I-level flash evaporator 3a, the II-level flash evaporator 3b, the III-level flash evaporator 3c, the IV-level flash evaporator 3d, and the V-level flash evaporator 3e in sequence through the finished product feed pump 14 for cooling and self-evaporation and concentration, and is collected by the discharge pump 15 to obtain the finished product solution; the stock solution entering the VII-effect heating chamber 1g is connected to the VI-effect heating chamber 1f for heating and evaporation, and is collected by the discharge pump 15 after concentration to obtain the finished product solution, and finally the finished products obtained by the first concentration branch and the second concentration branch are mixed and collected.

[0030] At the same time, the hot steam introduced by the high-temperature gas source first enters the I-effect heating chamber 1a through the external raw steam inlet pipe 9, heats and concentrates the solution in the I-effect heating chamber 1a, and the secondary steam evaporated from the I-effect heating chamber 1a enters the II-effect heating chamber 1b through the I-effect gas-liquid separation chamber 2a. Similarly, the secondary steam evaporated from the VI-effect heating chamber 1f enters the VII-effect heating chamber 1g through the VI-effect gas-liquid separation chamber 2f, and the secondary steam evaporated from the VII-effect heating chamber 1g enters the water cooler 10 through the VII-effect gas-liquid separation chamber 2g for cooling.

[0031] The secondary steam coming out of the first-stage flash evaporator 3a enters the second-effect gas-liquid separation chamber 2b, the secondary steam coming out of the second-stage flash evaporator 3b enters the third-effect gas-liquid separation chamber 2c, the secondary steam coming out of the third-stage flash evaporator 3c enters the fourth-effect gas-liquid separation chamber 2d, the secondary steam coming out of the fourth-stage flash evaporator 3d enters the fifth-effect gas-liquid separation chamber 2e, and the secondary steam coming out of the fifth-stage flash evaporator 3e enters the sixth-effect gas-liquid separation chamber 2f.

[0032] The utility model is described in detail above with reference to the accompanying drawings and embodiments. However, those skilled in the art will appreciate that, without departing from the spirit of the utility model, the specific parameters in the above embodiments may be changed to form a plurality of specific embodiments, which are all within the common variation range of the utility model and will not be described in detail here.

Claims

1. A condenser evaporator group for concentrating sodium aluminate solution, comprising an evaporator consisting of a heating chamber and a vapor-liquid separation chamber, at least a triple-effect evaporator connected in sequence to form a solution concentration circuit and a steam condensation circuit, characterized in that: The steam condensation circuit includes a primary steam condensation recovery branch and a secondary steam condensation recovery branch. The secondary steam condensation recovery branch includes a secondary condensate collection pipe. At least two adjacent evaporators of the two effects are directly connected in sequence through the secondary condensate collection pipe. The secondary steam condensation recovery branch also includes a secondary condensate collection tank on the secondary condensate collection pipe led out from the last effect evaporator.

2. The condenser evaporator group for concentrating sodium aluminate solution according to claim 1, characterized in that: The shell side of the heating chamber is connected to the secondary condensed water collecting pipe, and the shell side of the final effect heating chamber is connected to the secondary condensed water collecting tank through the secondary condensed water collecting pipe.

3. The condenser evaporator group for concentrating sodium aluminate solution according to claim 1, characterized in that: The heating chamber and the vapor-liquid separation chamber are split structures, and the seven-effect evaporators are connected in sequence to form a solution concentration loop and a steam circulation loop.

4. The condenser evaporator group for concentrating sodium aluminate solution according to claim 1, characterized in that: The solution concentration loop comprises a first concentration branch and a second concentration branch arranged in parallel, wherein the first concentration branch is composed of a V-effect evaporator, a IV-effect evaporator, a III-effect evaporator, a II-effect evaporator, an I-effect evaporator, a I-level flash evaporator, a II-level flash evaporator, a III-level flash evaporator, a IV-level flash evaporator, and a V-level flash evaporator connected in series in sequence, a feed port of the V-effect evaporator is connected to a raw liquid feed pipeline, and a discharge port of the V-level flash evaporator is connected to a finished product recovery pipeline.

5. The condenser evaporator group for concentrating sodium aluminate solution according to claim 4, characterized in that: The second concentration branch is composed of a VII effect evaporator and a VI effect evaporator connected in series in sequence. The feed port of the VII effect evaporator is connected to a raw liquid feed pipeline, and the discharge port of the VI effect evaporator is connected to a finished product recovery branch pipe arranged on a finished product recovery pipeline.

6. The condenser evaporator group for concentrating sodium aluminate solution according to claim 1, characterized in that: The primary steam condensation recovery branch includes an external raw steam inlet pipeline connected to the steam inlet of the heating chamber of the first-effect evaporator and a primary condensate collecting pipe connected to the condensate outlet of the heating chamber of the first-effect evaporator. A primary condensate collecting tank, a heat exchanger and a primary condensate pump are sequentially arranged on the primary condensate collecting pipe.

7. The condenser evaporator group for concentrating sodium aluminate solution according to claim 1, characterized in that: A circulating feeding pipeline is arranged between the lower discharge port and the top feeding port of each effective heating chamber.

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