Caprolactam flash evaporation system

Abstract

The caprolactam flash evaporation system comprises a separation kettle and a flash evaporation tank which are sequentially communicated, a liquid phase outlet pipe of the flash evaporation tank is communicated with a buffer tank, a gas phase outlet pipe of the flash evaporation tank is communicated with a mixer, an outlet pipe of the mixer is communicated with a condenser, and the condenser is provided with a vacuum pump for keeping the interior in a vacuum state. Compared with the prior art, the vacuum flash evaporation system has the beneficial effects that by improving the current vacuum flash evaporation system and abandoning an ejector with great water consumption, the efficient utilization of steam and condensate is realized, the energy conservation and the improvement of environmental protection benefits are greatly promoted, and by reducing the generation amount of the steam condensate, not only is the burden of subsequent wastewater treatment reduced, but also the production cost is reduced. The potential environmental pollution risk is reduced from the source, the green production and sustainable development goals of enterprises are favorably realized, and greater economic benefits are created for the enterprises.

Description

Technical Field

[0001] The utility model relates to the technical field of caprolactam flashing, and particularly relates to a caprolactam flashing system. Background Art

[0002] In the current field of caprolactam production, for the refining process of high-purity (over 99%) caprolactam, highly refined high-vacuum flashing and distillation technologies are adopted. The reason for choosing to carry out this technology in a high-vacuum environment is mainly based on the unique physical properties of caprolactam - its crystallization point is relatively high, reaching 69°C, which means that under lower pressure, caprolactam can be more effectively separated from the mixture, while avoiding premature crystallization, ensuring the purification efficiency and product quality.

[0003] In order to achieve and maintain this high-vacuum environment, the traditional process generally relies on a steam ejector system. The working principle of this system is to use high-pressure steam (usually requiring a pressure above 1.0 MPa) as the driving force. Through the special structural design of the ejector, the high-speed kinetic energy of the steam is converted into vacuum suction force, thereby effectively extracting the non-condensable gas in the system and forming and maintaining the required vacuum degree. However, in this process, the steam as the power source is finally discharged from the system in the form of condensed wastewater after completing its mission. This not only means that a large amount of steam resources are consumed, but also generates a considerable amount of process wastewater, increasing the burden and cost of subsequent wastewater treatment.

[0004] Therefore, although the high-vacuum flashing and distillation technologies are excellent in improving the purification efficiency of caprolactam, their high consumption of steam resources and wastewater discharge problems have also become one of the key factors restricting their sustainable development. Therefore, there is an urgent need for a new flashing system and a supporting flashing process that can save more steam resources. Content of the Utility Model

[0005] Aiming at the deficiencies of the prior art, to solve the problems of high consumption of steam resources and wastewater discharge in the current vacuum flashing technology;

[0006] The utility model provides a caprolactam flashing system, which includes a separation kettle and a flashing tank connected in sequence. The liquid phase outlet pipe of the flashing tank is connected to a buffer tank, the gas phase outlet pipe of the flashing tank is connected to a mixer, the outlet pipe of the mixer is connected to a condenser, and a vacuum pump for maintaining the internal vacuum state is arranged in the condenser.

[0007] Furthermore, the mixer is provided with a liquid inlet pipe for introducing steam or condensate.

[0008] Furthermore, the outlet pipe of the buffer tank is connected to a heavy component distillation system to transport high-purity caprolactam.

[0009] As a preferred solution, the mixer is an orifice plate mixer, and the mass ratio of the steam introduced to the light component gas is 3 / 8 to 5 / 8.

[0010] As a preferred solution, an atomizing nozzle for ensuring the mixing effect of the introduced condensate is arranged in the mixer.

[0011] As a preferred solution, the vacuum pump is a Roots water ring vacuum unit.

[0012] The beneficial effects of the present utility model are as follows:

[0013] By improving the current vacuum flashing system and abandoning the ejector with extremely high water consumption, the efficient utilization of steam and condensate is realized, which greatly promotes energy conservation and environmental protection benefits. And by reducing the generation amount of steam condensate, not only the burden of subsequent wastewater treatment is reduced, but also the potential environmental pollution risk is reduced from the source, which helps to achieve the green production and sustainable development goals of the enterprise and creates greater economic benefits for the enterprise. Description of the Drawings

[0014] In order to make the content of the present utility model easier to be clearly understood, the following further details the present utility model according to specific embodiments in conjunction with the drawings, where

[0015] Figure 1 The structural schematic diagram of the present utility model.

[0016] The reference numerals in the drawings are:

[0017] According to the provided text, the parts with reference numerals include:

[0018] 1. Separation kettle; 2. Flash tank; 21. Liquid phase outlet pipe; 22. Gas phase outlet pipe; 3. Mixer; 31. Liquid inlet pipe; 4. Buffer tank; 5. Mixer; 5. Condenser; 6. Vacuum pump. Detailed Embodiments

[0019] To illustrate the features of the present utility model, the following further describes the present utility model in conjunction with the drawings and embodiments.

[0020] Embodiment 1:

[0021] Please refer to Figure 1 , the embodiment of the present utility model provides a caprolactam flashing system, which includes a separation kettle 1 and a flash tank 2 connected in sequence, the liquid phase outlet pipe 21 of the flash tank 2 is connected to a buffer tank 4, the gas phase outlet pipe 22 of the flash tank 2 is connected to a mixer 3, the outlet pipe of the mixer 3 is connected to a condenser 5, and a vacuum pump 6 for maintaining the internal vacuum state is arranged on the condenser 5.

[0022] Specifically, the mixer 3 is provided with a liquid inlet pipe 31 for introducing steam. The mixer 3 uses an orifice plate mixer, and the mass ratio of the introduced steam to the light component gas is 5 / 8. To be precise, the current production capacity of our company is 300,000 tons. The light components are approximately 800 kilograms, and the steam used is approximately 500 kilograms.

[0023] In terms of the liquid phase treatment of flash evaporation, the outlet pipe of the buffer tank 4 is connected to the heavy component distillation system to transport high-purity caprolactam, and the heavy components of caprolactam are further separated. In this embodiment, the vacuum pump 6 is a Roots water ring vacuum unit, which can improve the pumping rate and efficiency, especially suitable for environments dealing with a large amount of condensable steam, and can reach a relatively high ultimate vacuum degree to meet the application requirements of high vacuum.

[0024] Embodiment 2:

[0025] Please refer to Figure 1 , this embodiment of the utility model provides a caprolactam flash evaporation system, which includes a separation kettle 1 and a flash tank 2 connected in sequence. The liquid phase outlet pipe 21 of the flash tank 2 is connected to a buffer tank 4, the gas phase outlet pipe 22 of the flash tank 2 is connected to a mixer 3, the outlet pipe of the mixer 3 is connected to a condenser 5, and the condenser 5 is provided with a vacuum pump 6 to maintain the internal vacuum state.

[0026] The mixer 3 is provided with a liquid inlet pipe 31 for introducing condensate. In this embodiment, to reduce the working pressure of the condenser 5 and further reduce the volume of the condenser 5, the mixing of steam and light component gas used in Embodiment 1 is improved to use condensate and light component gas for mixing. To ensure the full mixing of condensate and light component gas, an atomizing nozzle is also provided at the inner end of the liquid inlet pipe 31 of the mixer 3 to fully atomize the condensate, thereby ensuring the mixing degree with the light component gas. The mixer 3 uses an orifice plate mixer, and the flow rate of the introduced condensed water is 1 to 2 cubic meters per hour, so that the inlet air temperature of the condenser is controlled at 90 - 110 °C.

[0027] In terms of the liquid phase treatment of flash evaporation, the outlet pipe of the buffer tank 4 is connected to the heavy component distillation system to transport high-purity caprolactam, and the heavy components of caprolactam are further separated. In this embodiment, the vacuum pump 6 uses a Roots screw vacuum unit with a higher pumping speed efficiency, which can improve the pumping rate and efficiency, especially suitable for environments dealing with a large amount of condensable steam, and can reach a relatively high ultimate vacuum degree to meet the application requirements of high vacuum.

[0028] By improving the current vacuum flashing system and abandoning the ejector with extremely high water consumption, the efficient utilization of steam and condensate has been achieved, greatly promoting energy conservation and environmental protection benefits. Moreover, by reducing the generation amount of steam condensate, not only the burden of subsequent wastewater treatment is alleviated, but also the potential environmental pollution risk is reduced from the source, contributing to the realization of the enterprise's green production and sustainable development goals and creating greater economic benefits for the enterprise. This technological innovation not only reflects the pursuit of modern industry for efficient and environmentally friendly production methods, but also provides useful reference for the transformation and upgrading of the entire industry.

[0029] The above embodiments and the accompanying drawings are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. The present invention has been described in detail with reference to the preferred embodiments. Those of ordinary skill in the art should understand that any changes, modifications, additions or substitutions made by those of ordinary skill in the art within the scope of the essence of the present invention do not depart from the purpose of the present invention and should also fall within the protection scope of the claims of the present invention. Other related technical structures not exhaustively disclosed in the present invention are the prior art in this field.

Claims

1. A caprolactam flashing system, comprising a separation kettle (1) and a flashing tank (2) connected in sequence, and a liquid phase outlet pipe (21) of the flashing tank (2) is connected to a buffer tank (4), characterized in that: The gas-phase outlet pipe (22) of the flash tank (2) is connected to the mixer (3), the outlet pipe of the mixer (3) is connected to the condenser (5), and a vacuum pump (6) for maintaining the internal vacuum state is provided in the condenser (5).

2. The caprolactam flashing system according to claim 1, wherein: The mixer (3) is provided with a liquid inlet pipe (31) for introducing steam or condensate.

3. The caprolactam flashing system according to claim 1, wherein: The outlet pipe of the buffer tank (4) is connected to the heavy component distillation system to transport high-purity caprolactam.

4. The caprolactam flashing system according to claim 2, wherein: The mixer (3) is an orifice plate mixer, and the mass ratio of the introduced steam to the light component gas is 3 / 8 to 5 / 8.

5. The caprolactam flashing system according to claim 2, wherein: An atomizing nozzle for ensuring the mixing effect of the introduced condensate is provided in the mixer (3).

6. The caprolactam flashing system according to claim 1, wherein: The vacuum pump (6) is a Roots water ring vacuum unit.

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