Sieve plate type thin liquid distillation tower

Abstract

The utility model discloses a sieve plate type thin liquid distillation tower which sequentially comprises a base, a bottom storage barrel, a middle distillation section and a top cooling water tank from bottom to top, wherein the middle distillation section is provided with a plurality of layers of sieve plates, each sieve plate is provided with a plurality of sieve holes, and a gap is formed between every two adjacent sieve plates; an air inlet is formed below the sieve plate on the lowermost layer and is used for introducing steam; and a liquid inlet is formed above the sieve plate on the uppermost layer and is used for introducing ammonia-containing condensate (or diluted liquid). The treatment capacity of the light liquid distillation tower is multiplied compared with that of a packed tower, the operation period is long, the light liquid distillation tower can continuously run for 2-3 years without being cleaned, and the problem of low distillation efficiency is effectively solved. On the premise of ensuring the production efficiency, the height of the tower can be reduced by about 8-10 meters, the production cost is greatly reduced, and the processing capacity is nearly two times that of a packed tower with the same tower diameter. The thin liquid distillation tower disclosed by the utility model meets higher environmental protection requirements, and meanwhile, the production efficiency and economic benefits of sodium carbonate are also improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of dilute liquor distillation towers, and particularly relates to a sieve plate type dilute liquor distillation tower. Background Technique

[0002] In the soda ash production process, the dilute liquor distillation tower is mainly used to distill the ammonia-containing condensate, i.e., dilute liquor, to recover the ammonia therein and at the same time reduce the ammonia-nitrogen concentration in the dilute liquor to meet the requirements of discharge or reuse. This process is not only environmentally friendly but also economical because the recovered ammonia and carbon dioxide can be used in other process steps, reducing the waste of raw materials.

[0003] In industrial production, the packing in the dilute liquor distillation tower should have a large specific surface area and good porosity to avoid channeling and uneven flow, ensure sufficient contact between the vapor and liquid phases, and improve the distillation efficiency. In addition, the design of the tower should also consider the problem of mother liquor expansion, as well as the problem that as the production volume increases, the amount of dilute liquor will also increase correspondingly, resulting in a decrease in distillation efficiency and an increase in the ammonia content in the waste dilute liquor. Therefore, for large-scale soda ash plants, it is necessary to transform the dilute liquor distillation tower to meet higher production requirements. Currently, all the dilute liquor distillation towers used in soda ash production plants are of packing structure and must be overhauled and the packing replaced after a certain period of use. Specifically, the existing dilute liquor distillation towers in the prior art have the following problems:

[0004] 1. Reduction in distillation efficiency

[0005] As the production volume increases, the amount of dilute liquor increases, and the gas-liquid distribution in the dilute liquor distillation tower is uneven and the contact is poor, resulting in a reduction in distillation efficiency. In addition, due to site space limitations, the dilute liquor distillation tower cannot be enlarged in diameter for transformation, resulting in a reduction in production efficiency and an increase in energy consumption. At the same time, in the existing packed tower with Pall rings in the tower, the operation cycle is short, it is easy to be blocked, and the packing needs to be cleaned and replaced regularly, resulting in high operating costs.

[0006] 2. Material corrosion

[0007] Due to severe corrosion of the liquid distributor inside the dilute liquor distillation tower, uneven liquid distribution occurs, resulting in uneven flow, an increase in tower pressure, and a large steam consumption; the internal structure adopts a multi-stage packing structure, and after a certain period of use, problems such as scaling and a decrease in the packing gap occur; in this case, it is necessary to transform the internal structure of the tower to improve the service life and production efficiency of the equipment.

[0008] 3. Energy waste

[0009] During the distillation process, excessive steam consumption is a serious problem. Due to the poor liquid separation effect of the distributor between the two packings in the lower layer of the tower, uneven liquid distribution occurs, resulting in ammonia in the waste dilute liquor, too high tower pressure, liquid entrainment in the outlet gas, etc. These problems not only affect the stability of production but also lead to energy waste. Summary of the Invention

[0010] To solve the above technical problems, the present utility model provides a sieve-plate type weak liquor distillation column, which successively includes a base, a bottom storage barrel, an intermediate distillation section, and a top cooling water tank from bottom to top; wherein, the intermediate distillation section is provided with multiple layers of sieve plates, each sieve plate is provided with a plurality of sieve holes, and there is a gap between adjacent sieve plates;

[0011] A downcomer is further provided on each layer of sieve plate;

[0012] An air inlet is provided below the lowermost sieve plate for introducing steam;

[0013] A liquid inlet is provided above the uppermost sieve plate for introducing ammonia-containing condensate (or weak liquor).

[0014] According to an embodiment of the present utility model, the bottom storage barrel is used for collecting waste weak liquor. Preferably, in the waste weak liquor, the ammonia nitrogen content is below 80 ppm.

[0015] According to an embodiment of the present utility model, the distance between adjacent sieve plates is 500 - 1200 mm, preferably 700 - 1000 mm.

[0016] According to an embodiment of the present utility model, the sieve plates are at least 10 layers, for example, 10 - 40 layers.

[0017] According to an embodiment of the present utility model, a plurality of sieve holes are evenly distributed on the sieve plate.

[0018] According to an embodiment of the present utility model, on the sieve plate, any three sieve holes are distributed in a triangular shape.

[0019] According to an embodiment of the present utility model, the sieve plates are all located between two tower rings. The material of the tower body of the weak liquor distillation column of the present utility model is HT200 cast iron. When manufacturing the tower body, it cannot be manufactured integrally. The tower body needs to be divided into multiple tower rings. Each tower ring is integrally cast and then connected together by flanges to form the entire tower body.

[0020] According to an embodiment of the present utility model, the sieve plates are made of stainless steel.

[0021] According to an embodiment of the present utility model, the aperture of the sieve holes is 16 - 35 mm. Preferably, the opening ratio of the sieve holes is 6.5% - 19.2%.

[0022] According to the embodiments of the present utility model, the downcomer hole rate is 8.7% - 24.6%. The working principle of the sieve plate is to form an air cushion layer at the lower part of the sieve plate. The liquid flows downward from the downcomer, and the downcomer ensures a certain liquid level above the sieve plate. The steam passes upward through the sieve holes to fully contact the liquid; that is, the sieve holes are for the steam to go upward, and the downcomer is for the liquid to flow downward.

[0023] According to the embodiments of the present utility model, a liquid inlet pipe is provided on the liquid inlet. Preferably, the liquid inlet pipe is an L-shaped liquid inlet pipe.

[0024] According to the embodiments of the present utility model, an air inlet pipe is provided on the air inlet.

[0025] According to the embodiments of the present utility model, the cooling water tank is used to recover ammonia. Preferably, the shell of the cooling water tank is made of HT200 cast iron, and the internal heat exchange tube bundle of the cooling water tank is made of S31603 stainless steel or TA2 titanium.

[0026] The beneficial effects of the present utility model:

[0027] (1) The processing capacity of the dilute liquid distillation tower of the present utility model is several times higher than that of the packed tower, and the operation cycle is long. It can operate continuously for 2 - 3 years without cleaning, effectively solving the problem of low distillation efficiency. On the premise of ensuring production efficiency, the tower height can be reduced by about 8 - 10 meters, greatly reducing the production cost, and the processing capacity is nearly 2 times that of the packed tower with the same tower diameter. The dilute liquid distillation tower of the present utility model meets higher environmental protection requirements, and at the same time improves the efficiency and economic benefits of soda ash production.

[0028] (2) The sieve plate of the present utility model has the following advantages:

[0029] a. The gas pressure drop is small, and the liquid level drop on the plate is also small. The gas-liquid flow path of the sieve plate type dilute liquid distillation tower is relatively smooth, and the resistance encountered by the gas when passing through the sieve holes is small, so the gas pressure drop is relatively small. At the same time, since the liquid layer is evenly distributed on the tower plate, the liquid level drop on the plate is also small. These two characteristics help to reduce the energy consumption during the distillation process and improve the overall energy efficiency.

[0030] b. The tower plate efficiency is relatively high. The gas-liquid contact time of the sieve plate type dilute liquid distillation tower is long, and the mixing between gas and liquid is relatively sufficient, which helps to improve the mass transfer efficiency of the tower plate. In addition, the sieve plate type dilute liquid distillation tower also has a certain operation flexibility, that is, when the gas-liquid load fluctuates, it can still maintain a relatively high tower plate efficiency.

[0031] (3) The present utility model is provided with a separate cooling water tank at the top of the tower, which can effectively solve the situation that the cooling system does not meet the production needs caused by sharing the cooler with the mother liquid distillation.

[0032] (4) The internals of the dilute liquid distillation column of the present utility model are all made of stainless steel materials, effectively solving the problem of component corrosion and failure, and preventing the adverse situations of increased tower pressure and increased energy consumption caused by corrosion and scaling of the internals of the tower. Description of the Drawings

[0033] Figure 1 is a schematic structural diagram of the dilute liquid distillation column of the present utility model;

[0034] Figure 2 is an enlarged view of part A;

[0035] Figure 3 is a schematic structural diagram of the sieve plate;

[0036] Among them, 1, base; 2, bottom storage barrel; 3, sieve plate; 4, top cooling water tank; 5, tower cover; 6, tower ring. Detailed Embodiments

[0037] The technical solutions of the present utility model will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only illustrative explanations of the present utility model and should not be construed as limiting the protection scope of the present utility model. All technologies implemented based on the above content of the present utility model are covered within the scope of protection intended by the present utility model.

[0038] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0039] Embodiment 1

[0040] As Figure 1 shown, the overall height H of the dilute liquid distillation column produced by our company for the third branch of Jiangsu Suli Salt and God Co., Ltd. in 2021 and already in use is 30995 mm; the tower body diameter is 2730 mm. A sieve plate type dilute liquid distillation column includes a base 1, a bottom storage barrel 2, an intermediate distillation section, a top cooling water tank 4 and a tower cover 5 from bottom to top in sequence; among them, the intermediate distillation section is provided with 22 sieve plates 3, and each sieve plate is provided with a plurality of sieve holes, and the plurality of sieve holes are evenly distributed on the sieve plate. On the sieve plate, any three sieve holes are triangular in shape, and the distance between adjacent sieve plates is 1000 mm.

[0041] An air inlet is provided below the lowermost sieve plate, and an air inlet pipe is arranged on the air inlet for introducing steam;

[0042] A liquid inlet is provided above the uppermost sieve plate, and an L-shaped liquid inlet pipe is arranged on the liquid inlet for introducing ammonia-containing condensate.

[0043] The bottom storage barrel is used to collect waste dilute liquid, and the ammonia nitrogen content in the waste dilute liquid is below 80 ppm.

[0044] The sieve plate is located between two tower rings.

[0045] The sieve plate is made of stainless steel.

[0046] The aperture of the sieve holes is 20 - 25 mm. Preferably, the opening ratio of the sieve holes is 15.5% - 18.3%.

[0047] A downcomer is also provided on each sieve plate, and the opening ratio of the downcomer is 17.5 - 20.7%.

[0048] The cooling water tank recovers ammonia. The shell of the cooling water tank is made of HT200 cast iron, and the internal heat exchange tube bundle is made of S31603 stainless steel or TA2 titanium.

[0049] Above, the embodiments of the present utility model have been described exemplarily. However, the protection scope of the present utility model is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A sieve plate type dilute liquid distillation tower, characterized in that: From bottom to top, it includes a base, a bottom storage barrel, an intermediate distillation section, and a top cooling water tank; wherein the intermediate distillation section is provided with multiple layers of sieve plates, each sieve plate is provided with multiple sieve holes, and there are gaps between adjacent sieve plates; Each sieve plate is also provided with a downcomer; An air inlet is provided below the lowest sieve plate for introducing steam; A liquid inlet is provided above the uppermost sieve plate for introducing ammonia-containing condensate.

2. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: The bottom storage tank is used to collect waste dilute liquid.

3. The sieve plate type dilute liquid distillation tower according to claim 2, characterized in that: The ammonia nitrogen content in the waste dilute liquid is below 80ppm; The spacing between adjacent sieve plates is 500-1200mm; The sieve plates have at least 10 layers.

4. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: A plurality of sieve holes are evenly distributed on the sieve plate.

5. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: The sieve plates are all located between the two tower circles; The sieve plate is made of stainless steel.

6. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: The sieve hole has a diameter of 16 to 35 mm; And / or, the opening rate of the sieve holes is 6.5% to 19.2%.

7. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: The opening rate of the downcomer is 8.7% to 24.6%.

8. The sieve plate type dilute liquid distillation tower according to claim 1, characterized in that: The cooling water tank is used to recover ammonia; The shell of the cooling water tank is made of HT200 cast iron, and the internal heat exchange tube bundle of the cooling water tank is made of S31603 stainless steel or TA2 titanium.

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