Environment-friendly and energy-saving distillation device for soda production

Abstract

This utility model relates to the field of ammonia stripping technology and provides an environmentally friendly and energy-saving distillation apparatus for soda ash production, comprising an ammonia stripping tower, a steam ejector, and a first flash evaporator. The top and bottom of the first flash evaporator are connected to the ammonia stripping tower via pipelines. The top of the steam ejector is connected to the first flash evaporator via a pipeline, and the bottom of the steam ejector is connected to the ammonia stripping tower via a pipeline. The first flash evaporator is connected to a waste liquid pump via a pipeline. Preferably, a second flash evaporator is connected between the first flash evaporator and the waste liquid pump via a pipeline. Preferably, a liquid distributor is installed at the outlet of the inlet pipeline of the second flash evaporator. Preferably, the liquid distributor is an overflow tank. The distillation apparatus provided by this utility model can not only reduce the temperature of the distillation waste liquid and reduce the steam consumption in the ammonia stripping process, but also reduce the ammonia content in the waste liquid, reducing ammonia consumption, thereby reducing the production cost of soda ash.

Description

Technical Field

[0001] This utility model belongs to the field of ammonia distillation technology, and in particular relates to an environmentally friendly and energy-saving distillation device for the production of soda ash. Background Technology

[0002] The ammonia stripping process is a crucial step in the production of soda ash using the ammonia-soda process. Its main task is to recover ammonia and carbon dioxide from the filtered mother liquor using a mother liquor distillation tower with ash decomposition and steam-heated distillation. Simultaneously, it utilizes a distillation tower to recover ammonia and carbon dioxide from the distillation condensate and the condensate from the light ash furnace gas. Mother liquor ammonia stripping, limestone decomposition, and heavy soda ash calcination are the three major energy-consuming processes in an ammonia-soda plant, accounting for over 30% of the total energy consumption of the entire production process.

[0003] Currently, the distillation process for mother liquor in the ammonia-soda process is divided into two types: pressure distillation and vacuum distillation. The existing low-vacuum distillation process has the following drawbacks: ① The system vacuum is low, resulting in low flash intensity, high waste liquid temperature, and significant heat loss. Statistics show that the vacuum level in the first flash evaporator is approximately -2 kPa, the flash outlet temperature is 95-98℃, and the waste liquid temperature is approximately 93℃. The steam consumption in the ammonia stripping process is approximately 1500 kg / t of alkali, accounting for 55% of the total steam consumption for soda ash. The sensible heat carried away by the distillation residue and the heat energy from the ammonia stripping process account for as much as 70% of this, highlighting the significant heat loss. ② When connected to the ammonia system, the pressure in the middle of the ammonia stripping tower is around 0 kPa. When the negative pressure fluctuates, the pressure in the middle increases, causing a large amount of ammonia-containing gas inside the pre-ash tank to backflow into the primary flash evaporator, resulting in ammonia entrainment in the waste liquid, a sharp increase in ammonia consumption, and pollution of the surrounding atmosphere of the slag yard.

[0004] In summary, achieving energy conservation, high efficiency, and low consumption as much as possible in the ammonia recovery process is a crucial issue in the ammonia distillation process. Recovering and utilizing the sensible heat of the distillation waste liquid is a feasible way to reduce energy consumption in production. Therefore, this application proposes an environmentally friendly and energy-saving distillation apparatus for soda ash production. Utility Model Content

[0005] The purpose of this invention is to provide an environmentally friendly and energy-saving distillation apparatus for the production of soda ash, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: an environmentally friendly and energy-saving distillation device for soda ash production, comprising an ammonia stripping tower, a steam ejector, and a first flash evaporator. The top and bottom of the first flash evaporator are connected to the ammonia stripping tower via pipelines. The top of the steam ejector is connected to the first flash evaporator via a pipeline, and the bottom of the steam ejector is connected to the ammonia stripping tower via a pipeline. The first flash evaporator is connected to a waste liquid pump via a pipeline.

[0007] Preferably, a second flash generator is connected between the first flash generator and the waste liquid pump via a pipeline.

[0008] Preferably, a liquid distributor is installed at the outlet of the inlet line of the second flash generator.

[0009] Preferably, the liquid distributor is an overflow trough.

[0010] Preferably, the second flash emitter is a double-layer flash emitter.

[0011] Preferably, the waste liquid pump is connected to a waste liquid slag removal site via a pipeline.

[0012] This utility model has at least the following beneficial effects:

[0013] This invention provides an environmentally friendly and energy-saving distillation apparatus for soda ash production. It can not only reduce the temperature of the distillation waste liquid and reduce the steam consumption in the ammonia stripping process, but also reduce the ammonia content in the waste liquid and reduce ammonia consumption, thereby reducing the production cost of soda ash. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model.

[0015] In the attached diagram, the following are the reference numerals: 1. Ammonia stripping tower; 2. Steam ejector; 3. First flash evaporator; 4. Second flash evaporator; 5. Waste liquid pump. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model.

[0017] Example

[0018] Please see Figure 1 This utility model provides a technical solution: an environmentally friendly and energy-saving distillation device for soda ash production, comprising an ammonia stripping tower 1, a steam ejector 2, and a first flash evaporator 3. The top and bottom of the first flash evaporator 3 are connected to the ammonia stripping tower 1 via pipelines. The top of the steam ejector 2 is connected to the first flash evaporator 3 via a pipeline, and the bottom of the steam ejector 2 is connected to the ammonia stripping tower 1 via a pipeline. The first flash evaporator 3 is connected to a waste liquid pump 5 via a pipeline. The waste liquid pump 5 is connected to a waste liquid slag removal area via a pipeline. The first flash evaporator 3 is connected to a pre-ash tank via a pipeline.

[0019] The first flash evaporator 3 is connected to the waste liquid pump 5 via a pipeline to the second flash evaporator 4; a liquid distributor is installed at the outlet of the inlet pipeline of the second flash evaporator 4; the liquid distributor is an overflow tank; the second flash evaporator 4 is a double-layer flash evaporator; the second flash evaporator 4 is connected to a distillation tower via a pipeline.

[0020] Working principle and usage process of this utility model:

[0021] The waste liquid formed after the ammonia in the mother liquor is distilled off in the ammonia stripping tower 1 enters the first flash evaporator 3 from the bottom ring of the tower. The flash vapor after flashing enters the steam ejector, and the motive steam drives the steam ejector 2 to do work. The steam ejector 2 causes the vacuum degree in the first flash evaporator 3 to increase. The flash vapor is then incorporated into the original single-tower steam pipeline and enters the bottom of the ammonia stripping tower 1 for secondary utilization. The waste liquid after the first-stage flashing enters the second flash evaporator 4. The steam flashed from the second flash evaporator 4 enters the 9th ring of the distillation tower as the steam source for the distillation tower. The waste liquid from the second flash evaporator 4 is sent to the waste liquid slag removal area by the waste liquid pump 5.

[0022] Using steam at different pressures as power, the steam ejector 2 is driven to do work. The steam ejector 2 drives the vacuum degree in the first flash evaporator 3 to reduce the temperature of the second flash waste liquid, thereby realizing the recovery of waste liquid heat.

[0023] An overflow tank is installed at the outlet of the inlet pipeline of the second flash evaporator 4 as a liquid distributor. After the waste liquid from the first flash enters the overflow tank, it flows down evenly. The second flash evaporator 4 adopts a double-layer flash, which increases the flash area of ​​the waste liquid from the first flash and the residence time in the second flash, which is conducive to the further recovery of waste heat and can solve the problem of insufficient steam source heat in the distillation tower.

[0024] This solution: ① Utilizes jet technology to generate a high-speed airflow using steam injection, creating a vacuum within the flash evaporator, causing the high-temperature distillation waste liquid to flash and release steam due to pressure reduction; ② Uses exhaust steam as motive steam to drive the ejector, further reducing the vacuum level within the first flash evaporator, thereby lowering the temperature of the second flash waste liquid. The secondary steam obtained from the second flash can be directly used for mother liquor distillation, achieving the recovery and utilization of waste heat; ③ The flash evaporation gas no longer enters the middle of the ammonia stripping tower, but instead is incorporated into the original single-tower steam pipeline and enters the bottom of the ammonia stripping tower, eliminating the problem of ammonia-containing gas in the pre-ash tank backflowing into the first-stage flash evaporator, effectively reducing the ammonia content in the waste liquid.

[0025] In summary, this application can not only reduce the temperature of the distillation waste liquid and reduce the steam consumption in the ammonia stripping process, but also reduce the ammonia content in the waste liquid and reduce ammonia consumption, thereby reducing the production cost of soda ash.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or basic characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description. Therefore, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this utility model, and no reference numerals in the claims should be construed as limiting the scope of the claims.

[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An environmentally friendly and energy-saving distillation device for soda production, characterized in that, It includes an ammonia stripping tower (1), a steam ejector (2) and a first flash evaporator (3). The top and bottom of the first flash evaporator (3) are connected to the ammonia stripping tower (1) through pipelines. The top of the steam ejector (2) is connected to the first flash evaporator (3) through pipelines. The bottom of the steam ejector (2) is connected to the ammonia stripping tower (1) through pipelines. The first flash evaporator (3) is connected to the waste liquid pump (5) through pipelines. A second flash generator (4) is connected to the first flash generator (3) and the waste liquid pump (5) through a pipeline; The second flash generator (4) is a double-layer flash generator.

2. The environment-friendly and energy-saving distillation device for soda production according to claim 1, characterized in that: The liquid distributor is installed at the outlet of the liquid inlet line of the second flash generator (4).

3. The environment-friendly and energy-saving distillation device for soda production according to claim 2, characterized in that: The liquid distributor is an overflow tank.

4. The environment-friendly and energy-saving distillation device for soda production according to claim 1, characterized in that: The waste liquid pump (5) is connected to the waste liquid slag removal site via a pipeline.

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