Sebacic acid acidification crystallization device

Abstract

The utility model provides a sebacic acid acidification crystallization device which comprises a monosodium salt aqueous solution input pipeline, a concentrated sulfuric acid input pipeline, a tubular heat exchanger, a multi-stage acidification crystallization kettle, a centrifugal machine and a tail gas removal tower, the multi-stage acidification crystallization kettle is formed by connecting ten stages of unit kettles in parallel in series, and stirrers are mounted in the unit kettles; the upper end of each unit kettle is provided with a feed port and a tail gas removal pipe, the lower end of each unit kettle is provided with a crystallization liquid output pipe, the monosodium salt aqueous solution input pipeline is connected with the feed port of the first-stage unit kettle through the tubular heat exchanger, and the concentrated sulfuric acid input pipeline is connected with the feed port of the first-stage unit kettle. An acidizing fluid outflow pipeline is arranged between every two adjacent stages of unit kettles, the tail gas removal pipe of each stage of unit kettle is connected with the tail gas removal tower, and the crystallization fluid output pipeline of each stage of unit kettle is connected with the centrifugal removal machine. The sebacic acid acidification crystallization device disclosed by the utility model is high in purity of separated products and low in energy consumption.

Description

Technical Field

[0001] The utility model belongs to the technical field of sebacic acid production, and particularly relates to a sebacic acid acidification crystallization device. Background Art

[0002] Sebacic acid is a white flaky crystal, slightly soluble in water, soluble in organic solvents such as ethanol and ether, flammable and non-toxic, while its industrial products are slightly yellow. Sebacic acid is an important fine chemical intermediate and an important dibasic acid produced by non-petroleum routes. It can replace petroleum to produce a variety of chemicals and is widely used in the chemical industry. For example, a series of polymerization products can be prepared from sebacic acid, such as engineering plastics, a variety of acetic acid products, lubricants, diluents, cold-resistant plasticizers, and high-temperature lubricating oils. More than 90% of the world's sebacic acid production comes from China. At present, the main way to industrially produce sebacic acid is to use castor oil as raw material. Its production process is to hydrolyze castor oil with a catalyst to produce ricinoleic acid, and then obtain it by high-temperature alkali cleavage. Chinese invention CN102826991B discloses a continuous acidification process and equipment in the acidification section of sebacic acid production. The equipment includes a storage tank, a pipeline pump, an acidifier, a heating tank, an acidification crystallization tank. A pipeline pump is installed at the outlet of the storage tank, and the outlet of the pipeline pump is connected to the inlet of the acidifier through a pipeline. The spatial positions of the four equipment, namely the acidifier, the heating tank, the acidification crystallization tank and the thickener, are connected and fixed by pipelines from top to bottom. The heating tank is a two-stage heating tank connected in series up and down, and the acidification crystallization tank is a sixteen-stage acidification crystallization tank connected in series up and down. A stirrer is installed in the acidification crystallization tank. The bottom of the first three-stage acidification crystallization tank is a jacket at the position of the front coil. The outlet of the last-stage acidification crystallizer is connected to the inlet of the thickener through a pipeline, and a stirrer is installed in the thickener. The decolorized liquid of the above equipment needs to be heated to 85°C - 100°C by steam, pumped into the acidifier, and sulfuric acid is added at the same time. The pH value is controlled at 1 - 3 to make the liquid material mix and boil, and then cooled for crystallization. The above process is carried out in a boiling state. The crystallization speed is too fast, resulting in small molecule organic impurities in the liquid material being wrapped in the crystal, affecting the color number and purity of the product, and having high energy consumption. At the same time, the pH value is relatively low, which causes great corrosion to the equipment. Summary of the Invention

[0003] The technical problem solved by the utility model is the problems of high energy consumption, large corrosion to equipment and poor product purity in the existing boiling acidification process.

[0004] The utility model provides a decanedioic acid acidification crystallization device, which includes a monosodium salt aqueous solution input pipeline, a concentrated sulfuric acid input pipeline, a tubular heat exchanger, a multi-stage acidification crystallization kettle, a centrifuge, and a tail gas tower. The multi-stage acidification crystallization kettle is composed of ten-stage unit kettles connected in parallel in series. A stirrer is installed in the unit kettle. The upper end of the unit kettle is provided with a feed inlet and a tail gas pipe, and the lower end of the unit kettle is provided with a crystallization liquid output pipe. The outer wall of the first-stage unit kettle is provided with a jacket, and a low-pressure steam pipe is connected to the jacket. The outer walls of the fourth to tenth-stage unit kettles are provided with cooling jackets. The monosodium salt aqueous solution input pipeline is connected to the feed inlet of the first-stage unit kettle through the tubular heat exchanger, and the concentrated sulfuric acid input pipeline is connected to the feed inlet of the first-stage unit kettle. An acidification liquid outflow pipeline is provided between adjacent two-stage unit kettles. The tail gas pipes of each stage of unit kettles are connected to the tail gas tower, and the crystallization liquid output pipes of each stage of unit kettles are connected to the centrifuge.

[0005] Further, the tubular heat exchanger is used to preheat the monosodium salt aqueous solution to a temperature of 83 ± 1 °C.

[0006] Further, the first-stage unit kettle is used to mix the concentrated sulfuric acid and the preheated monosodium salt aqueous solution for acidification, and the pH value of the mixed solution is 5.6 ± 0.1.

[0007] Further, it also includes a filter, and the filter is connected between the concentrated sulfuric acid input pipeline and the first-stage unit kettle.

[0008] Further, flow meters are provided on both the monosodium salt aqueous solution input pipeline and the concentrated sulfuric acid input pipeline.

[0009] Further, the feed inlet of the tubular heat exchanger is arranged at the bottom, the discharge outlet is arranged at the top, a thermometer is provided at the discharge outlet, and a condensate outlet is also provided at the bottom side of the tubular heat exchanger, and a pressure gauge is provided at the condensate outlet.

[0010] Further, the stirrer is provided with a stirring shaft, the stirring shaft extends along the inner shaft of the unit kettle, and multiple groups of stirring blades are arranged on the surface of the stirring shaft from top to bottom.

[0011] Further, the lower ends of the cooling jackets of the ninth and tenth unit kettles are connected to a circulating water supply pipeline, and the upper ends of the cooling jackets of the fourth to tenth unit kettles are connected to a circulating water return pipeline.

[0012] Further, it also includes a cooling tank, one end of the cooling tank is connected to the upper side of the tenth-stage unit kettle, and the other end is connected to a mother liquor tank.

[0013] The utility model has the following beneficial effects: (1) The crystallization temperature of the sebacic acid acidification crystallization device of the utility model is accurately controlled to 83 (±1) °C. During the crystallization process at this temperature, the crystallization speed is appropriately slowed down compared with the boiling state, and there is a "crystal nurturing" process, so that the precipitated sebacic acid crystals are in the shape of "snowflakes", with a lower color number and high product purity. (2) The temperature is reduced compared with the boiling acidification process, achieving the effect of energy conservation and consumption reduction. (3) The pH value is controlled at 5.6 (±1), weakening the influence of equipment corrosion. Brief Description of the Drawings

[0014] Figure 1 Schematic diagram of the sebacic acid acidification crystallization device of the utility model. Detailed Embodiments

[0015] To clearly illustrate the technical features of this solution, the following is an elaboration of this solution through specific embodiments and in conjunction with its drawings. Obviously, the described embodiments are only a part of the embodiments of the utility model, rather than all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative efforts shall fall within the scope of protection of the utility model.

[0016] In the description of the utility model, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the utility model, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the utility model.

[0017] As Figure 1 shown, a sebacic acid acidification crystallization device includes a monosodium salt aqueous solution input pipeline, a concentrated sulfuric acid input pipeline, a tubular heat exchanger 1, a multi-stage acidification crystallization kettle 2, a centrifuge, and a tail gas tower.

[0018] Flow meters are provided on both the monosodium salt aqueous solution input pipeline and the concentrated sulfuric acid input pipeline. The bottom of the tubular heat exchanger 1 is provided with a feed inlet, the top is provided with a discharge outlet, a thermometer is provided at the discharge outlet, and a condensate outlet is provided at the bottom side of the tubular heat exchanger 1, and a pressure gauge is provided at the condensate outlet.

[0019] The multi-stage acidification crystallization kettle 2 is composed of ten parallel-connected unit kettles in series. The upper end of the unit kettle is provided with a feed inlet and a tail gas output pipe, the lower end of the unit kettle is provided with a crystallization liquid output pipe, and a stirrer is installed in the unit kettle. The stirrer is provided with a stirring shaft, and the stirring shaft extends along the inner shaft of the unit kettle. Multiple groups of stirring blades are arranged on the surface of the stirring shaft from top to bottom. The outer wall of the first-stage unit kettle is provided with a sandwich layer, and a low-pressure steam pipe is connected to the sandwich layer. The outer walls of the fourth to tenth-stage unit kettles are provided with cooling sandwich layers. The lower ends of the cooling sandwich layers of the ninth and tenth unit kettles are connected to a circulating water supply pipeline, and the upper ends of the cooling sandwich layers of the fourth to tenth unit kettles are connected to a circulating water return pipeline.

[0020] The input pipeline of the monosodium salt aqueous solution is connected to the feed inlet of the first-stage unit kettle through the tubular heat exchanger 1, and the concentrated sulfuric acid input pipeline is connected to the feed inlet of the first-stage unit kettle through a filter. The filter is used to remove impurities in the concentrated sulfuric acid. An acidification liquid outflow pipeline is provided between adjacent two-stage unit kettles. The tail gas pipes of each unit kettle are connected to a tail gas tower, and the crystallization liquid output pipelines of each unit kettle are connected to a centrifuge. The tenth-stage unit kettle is also connected to a cooling tank 3, and the other end of the cooling tank 3 is connected to a mother liquor pool. The mother liquor pool is used to recover the liquid and recycle it.

[0021] The tubular heat exchanger 1 is used to preheat the monosodium salt aqueous solution and heat it to 83 ± 1 °C. The crystallization rate at this temperature is relatively slow, and there is a "crystal cultivation" process, so that the precipitated sebacic acid crystals are in the shape of "snowflake" crystals, avoiding the situation that small molecular organic impurities in the monosodium salt aqueous solution are wrapped in the crystals due to too fast crystallization rate, which affects the color number and purity of the product.

[0022] The first-stage unit kettle is used to mix the concentrated sulfuric acid and the preheated monosodium salt aqueous solution for acidification. The pH value of the mixed solution is 5.6 ± 0.1, and the mixed solution is cooled through the low-pressure steam pipe connected to the outer wall sandwich layer of the first-stage unit kettle to keep its temperature at 83 ± 1 °C. In this process, the mixed solution will crystallize. The sebacic acid crystals enter the centrifuge through the crystallization liquid output pipe below under the action of gravity, and the upper mixed solution enters the next-stage unit kettle through the acidification liquid outflow pipeline for crystallization. After the mixed solution is naturally cooled and crystallized in the second and third-stage unit kettles, it enters the fourth to tenth-stage unit kettles for secondary cooling crystallization through the cooling water sandwich layer. Crystallization occurs in each unit kettle, and the most crystals are generated in the ninth-stage unit kettle. The sebacic acid crystals generated in each unit kettle enter the centrifuge through the crystallization liquid output pipeline for centrifugal dehydration and drying to obtain the finished product.

[0023] Other parts not described in detail in the present utility model belong to the prior art, so they will not be elaborated here.

[0024] It can be understood that the present utility model is described through some embodiments. Those skilled in the art know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present utility model. Additionally, under the teaching of the present utility model, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the present utility model. Therefore, the present utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application belong to the scope protected by the present utility model.

Claims

1. A sebacic acid acidification crystallization device, characterized in that: It includes a monosodium salt aqueous solution input pipeline, a concentrated sulfuric acid input pipeline, a tubular heat exchanger, a multi-stage acidification crystallization kettle, a centrifuge, and a tail gas tower. The multi-stage acidification crystallization kettle is composed of ten unit kettles in parallel and connected in series, wherein a stirrer is installed in the unit kettle, a feed inlet and a tail gas removal pipe are arranged at the upper end of the unit kettle, a crystallization liquid output pipe is arranged at the lower end of the unit kettle, an interlayer is arranged on the outer wall of the first unit kettle, a low-pressure steam pipe is connected to the interlayer, and a cooling interlayer is arranged on the outer wall of the fourth to tenth unit kettles, The monosodium salt aqueous solution input pipeline is connected to the first-stage unit kettle feed port via a tubular heat exchanger, the concentrated sulfuric acid input pipeline is connected to the first-stage unit kettle feed port, an acidified liquid outflow pipeline is provided between two adjacent unit kettles, the tail gas removal pipes of each stage of the unit kettle are connected to the tail gas removal tower, and the crystallization liquid output pipelines of each stage of the unit kettle are connected to the de-centrifuge.

2. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The tubular heat exchanger is used to preheat the monosodium salt aqueous solution to a temperature of 83±1°C.

3. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The first-stage unit kettle is used to mix concentrated sulfuric acid and a preheated monosodium salt aqueous solution for acidification, and the pH value of the mixed solution is 5.6±0.

1.

4. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The invention also comprises a filter, wherein the filter is connected between the concentrated sulfuric acid input pipeline and the first-stage unit kettle.

5. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The monosodium salt aqueous solution input pipeline and the concentrated sulfuric acid input pipeline are both provided with flow meters.

6. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The inlet of the tubular heat exchanger is arranged at the bottom, the outlet is arranged at the top, a thermometer is arranged at the outlet, and a condensate outlet is arranged at the bottom of the side of the tubular heat exchanger, and a pressure gauge is arranged at the condensate outlet.

7. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The stirrer is provided with a stirring shaft, which extends along the inner shaft of the unit kettle, and a plurality of stirring blades are arranged on the surface of the stirring shaft from top to bottom.

8. The sebacic acid acidification crystallization device according to claim 1, characterized in that: The lower ends of the ninth and tenth unit kettle cooling interlayers are connected to circulating water supply pipelines, and the upper ends of the fourth to tenth unit kettle cooling interlayers are connected to circulating water return pipelines.

9. The sebacic acid acidification crystallization device according to claim 1, characterized in that: It also includes a cooling tank, one end of which is connected to the upper end of the side of the tenth-stage unit kettle, and the other end of which is connected to a mother liquor removal tank.

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