Ethylene glycol rectification system

Abstract

The utility model provides a kind of ethylene glycol rectification system, it is related to ethylene glycol rectification technical field, including ethylene glycol concentration tower, reboiler and dealcoholization tower;Wherein, reboiler is as the external device of ethylene glycol concentration tower, and is communicated with ethylene glycol concentration tower by heat exchange tube bundle, so that liquid phase in ethylene glycol concentration tower circulates through the heat exchange tube bundle of reboiler and carries out heat exchange;The heat source inlet end of reboiler is communicated with the heat pump being set in the top of dealcoholization tower, and heat pump is used to deliver the gas phase generated by dealcoholization tower to reboiler as the heat source of reboiler, by additionally setting ethylene glycol concentration tower in ethylene glycol rectification system, gas phase generated by dealcoholization tower is sent to reboiler by heat pump, liquid phase material in ethylene glycol concentration tower is heated without increasing steam consumption, realize dealcoholization tower and the double-effect rectification effect of ethylene glycol concentration tower, simultaneously reduce the problem that circulating water consumption increases due to the need of using circulating water for cooling in the gas phase cooling of existing dealcoholization tower top.

Description

Technical Field

[0001] This utility model relates to the field of ethylene glycol distillation technology, and specifically to an ethylene glycol distillation system. Background Technology

[0002] Ethylene glycol distillation refers to the process of recovering as much ethylene glycol as possible from crude ethylene glycol through continuous multi-tower distillation under negative pressure, thereby reducing energy consumption and ensuring that the extracted ethylene glycol meets the quality requirements of polyester-grade ethylene glycol.

[0003] In the existing technology, when using a dealcoholization tower for the purification of ethylene glycol, the boiling points of 1,2-butanediol in crude ethylene glycol are close to those of ethylene glycol, making separation difficult. The dealcoholization tower often needs to use a large reflux ratio with a reflux pump to increase the separation efficiency of 1,2-butanediol and ethylene glycol. However, the current use of a large reflux ratio in the dealcoholization tower leads to an increase in the overall steam consumption of the unit, and the high temperature of the gas phase at the top of the dealcoholization tower requires the use of circulating water for cooling, which wastes heat source and increases the consumption of circulating water.

[0004] Therefore, how to provide a low-consumption ethylene glycol distillation system is a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this utility model provides an ethylene glycol distillation system that solves the problems of increased overall steam consumption in the current dealcoholization tower due to its large reflux ratio, and the high temperature of the gas phase at the top of the dealcoholization tower requiring the use of circulating water for cooling, which wastes heat and increases the consumption of circulating water.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] In this invention, the ethylene glycol distillation system includes an ethylene glycol concentration tower, a reboiler, and a dealcoholization tower.

[0010] The reboiler is an external device of the ethylene glycol concentration tower and is connected to the ethylene glycol concentration tower through a heat exchange tube bundle, so that the liquid phase in the ethylene glycol concentration tower circulates through the heat exchange tube bundle of the reboiler for heat exchange.

[0011] The heat pump installed at the top of the dealcoholization tower is connected to the heat source inlet of the reboiler. The heat pump is used to transport the gas phase generated by the dealcoholization tower to the reboiler as the heat source of the reboiler.

[0012] Furthermore, the reboiler is externally connected to a condenser;

[0013] The condenser is connected to the heat source outlet of the reboiler and is used to transport the gas-liquid mixture formed after the reboiler uses the heat source to the condenser for cooling.

[0014] Furthermore, the inlet temperature of the circulating water in the condenser is 30°C.

[0015] Furthermore, the material level in the reboiler and the liquid level in the ethylene glycol concentration tower are at the same height.

[0016] Furthermore, the gas phase in the dealcoholization tower is pressurized by a heat pump to reach a gas phase temperature of 160°C.

[0017] Furthermore, the reboiler is a thermosiphon reboiler.

[0018] Furthermore, control valves are installed on the ethylene glycol concentration tower, reboiler, dealcoholization tower, and condenser.

[0019] Furthermore, each control valve is fitted with a shock absorber adjacent to it.

[0020] (III) Beneficial Effects

[0021] This invention provides an ethylene glycol distillation system. Compared with the prior art, it has the following advantages:

[0022] By adding an ethylene glycol concentration tower to the ethylene glycol distillation system, the light components collected from the top of the dealcoholization tower are sent to the ethylene glycol concentration tower. Ethylene glycol in the light components is recovered through concentration, thus reducing the loss of ethylene glycol during the ethylene glycol distillation process.

[0023] Furthermore, the gas phase generated by the dealcoholization tower is sent to the reboiler via a heat pump as a heat source for the reboiler. The gas phase is then pressurized by the reboiler to raise its temperature, thereby heating the liquid phase material in the ethylene glycol concentration tower without increasing steam consumption. This achieves a dual-effect distillation effect between the dealcoholization tower and the ethylene glycol concentration tower, while also reducing the problem of increased circulating water consumption caused by the need for circulating water to cool the gas phase at the top of the existing dealcoholization tower. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of an ethylene glycol distillation system.

[0026] Figure label:

[0027] 1. Ethylene glycol concentration tower; 2. Reboiler; 3. De-alcoholization tower; 4. Condenser. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions in the embodiments of this utility model are described clearly and completely. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] This application provides an ethylene glycol distillation system that solves the problems of increased overall steam consumption in the current dealcoholization tower due to its large reflux ratio, and the high temperature of the gas phase at the top of the dealcoholization tower requiring the use of circulating water for cooling, which wastes heat and increases the consumption of circulating water. This system achieves better energy-saving performance in the ethylene glycol distillation system.

[0030] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0031] In the existing technology, when using a dealcoholization tower for the purification of ethylene glycol, the boiling points of 1,2-butanediol in crude ethylene glycol are close to those of ethylene glycol, making separation difficult. The dealcoholization tower often needs to use a large reflux ratio of the reflux pump to increase the separation efficiency of 1,2-butanediol and ethylene glycol. However, the current use of a large reflux ratio in the dealcoholization tower leads to an increase in the overall steam consumption of the unit, and the high temperature of the gas phase at the top of the dealcoholization tower requires the use of circulating water for cooling, which wastes heat source and increases the consumption of circulating water.

[0032] Research has found that, for example Figure 1 As shown, by adding an ethylene glycol concentration tower to the ethylene glycol distillation system, the light components collected from the top of the dealcoholization tower are sent to the ethylene glycol concentration tower. Ethylene glycol in the light components is recovered through concentration, thereby reducing the loss of ethylene glycol during the ethylene glycol distillation process.

[0033] Furthermore, the gas phase generated by the dealcoholization tower is sent to the reboiler via a heat pump as a heat source for the reboiler. The gas phase is then pressurized by the reboiler to raise its temperature, thereby heating the ethylene glycol concentration tower without increasing steam consumption. This achieves a dual-effect distillation effect between the dealcoholization tower and the ethylene glycol concentration tower, while also reducing the problem of increased circulating water consumption caused by the need for circulating water to cool the gas phase at the top of the existing dealcoholization tower.

[0034] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0035] Example:

[0036] like Figure 1 As shown, an ethylene glycol distillation system includes an ethylene glycol concentration tower 1, a reboiler 2, and a dealcoholization tower 3.

[0037] Among them, the reboiler 2 is an external device of the ethylene glycol concentration tower 1, and is connected to the ethylene glycol concentration tower 1 through a heat exchange tube bundle, so that the liquid phase in the ethylene glycol concentration tower 1 circulates through the heat exchange tube bundle of the reboiler 2 for heat exchange.

[0038] The heat pump installed at the top of the dealcoholization tower 3 is connected to the heat source inlet of the reboiler 2. The heat pump is used to transport the gas phase generated by the dealcoholization tower 3 to the reboiler 2 as the heat source of the reboiler 2.

[0039] It should be noted that when the reboiler 2 is installed and used, the liquid level of the reboiler 2 and the liquid level of the ethylene glycol concentration tower 1 are at the same height.

[0040] When heat exchange is carried out using reboiler 2: the liquid phase supplied from the bottom of ethylene glycol concentration tower 1 enters reboiler 2. After being heated by an external heat source, part of the liquid phase flowing in reboiler 3 is vaporized and sent back to ethylene glycol concentration tower 1 to form a two-phase flow. At this time, the gas phase component in the returned tower rises and is condensed by the top condenser to form a liquid phase component that falls back to the bottom of the tower for subsequent distillation process in ethylene glycol concentration tower 1.

[0041] Specifically, the gas phase in the dealcoholization tower 3 is pressurized by a heat pump to reach a gas phase temperature of 160°C;

[0042] The reboiler 2 is a thermosiphon reboiler.

[0043] By adding an ethylene glycol concentration tower 1 to the ethylene glycol distillation system, the light components collected from the top of the dealcoholization tower 3 are sent to the ethylene glycol concentration tower 1. Ethylene glycol in the light components is recovered through concentration, thus reducing the loss of ethylene glycol during the ethylene glycol distillation process.

[0044] Furthermore, the gas phase generated by the dealcoholization tower 3 is sent to the reboiler 2 via a heat pump as a heat source for the reboiler 2. The gas phase is then pressurized by the reboiler 2 to raise its temperature, thereby heating the liquid phase material formed in the ethylene glycol concentration tower 1 without increasing steam consumption. This achieves a dual-effect distillation effect between the dealcoholization tower 3 and the ethylene glycol concentration tower 1, while also reducing the problem of increased circulating water consumption caused by the need to use circulating water for cooling the top gas phase of the existing dealcoholization tower 3.

[0045] In summary, the above solution solves the problems of increased overall steam consumption in the current dealcoholization tower 3 due to its large reflux ratio, and the high temperature of the gas phase at the top of the dealcoholization tower 3, which requires the use of circulating water for cooling, resulting in both heat source waste and increased circulating water consumption. This solution achieves better energy-saving performance in the ethylene glycol distillation system.

[0046] like Figure 1 As shown, the reboiler 2 is externally connected to a condenser 4;

[0047] The condenser 4 is connected to the heat source outlet of the reboiler 2 and is used to transport the gas-liquid mixture formed by the reboiler 2 after using the heat source to the condenser 4 for cooling.

[0048] The inlet temperature of the circulating water in condenser 4 is 30℃.

[0049] By adding a condenser 4 outside the reboiler 2, the gas-liquid mixture after being cooled by the reboiler 2 is cooled by the condenser 4, thereby achieving the effect of energy saving and environmental protection.

[0050] It should be noted that control valves are installed on ethylene glycol concentration tower 1, reboiler 2, dealcoholization tower 3 and condenser 4 to control the opening and closing of the corresponding flow ports and related flow parameters.

[0051] Each control valve is fitted with a shock absorber to reduce the impact of vibration on the control valve and improve the long-term safety of the system.

[0052] In summary, compared with existing technologies, it has the following beneficial effects:

[0053] 1. By adding an ethylene glycol concentration tower 1 to the ethylene glycol distillation system, the light components collected from the top of the dealcoholization tower 3 are sent to the ethylene glycol concentration tower 1. Ethylene glycol in the light components is recovered through concentration, thereby reducing the loss of ethylene glycol during the ethylene glycol distillation process.

[0054] 2. Furthermore, the gas phase generated by the dealcoholization tower 3 is sent to the reboiler 2 via a heat pump as a heat source for the reboiler 2. The gas phase is then pressurized and heated by the reboiler 2, which heats the liquid phase material in the ethylene glycol concentration tower 1 without increasing steam consumption. This achieves a dual-effect distillation effect between the dealcoholization tower 3 and the ethylene glycol concentration tower 1, while reducing the need for circulating water to cool the gas phase at the top of the existing dealcoholization tower 3, which would otherwise lead to increased circulating water consumption.

[0055] 3. By adding a condenser 4 outside the reboiler 2, the gas-liquid mixture after being cooled by the reboiler 2 is cooled down by the condenser 4, thereby achieving the effect of energy saving and environmental protection.

[0056] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0057] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. An ethylene glycol distillation system, characterized in that, It includes an ethylene glycol concentration tower (1), a reboiler (2), and a dealcoholization tower (3); Among them, the reboiler (2) is an external device of the ethylene glycol concentration tower (1) and is connected to the ethylene glycol concentration tower (1) through the heat exchange tube bundle, so that the liquid phase in the ethylene glycol concentration tower (1) circulates through the heat exchange tube bundle of the reboiler (2) for heat exchange. The heat pump installed at the top of the dealcoholization tower (3) is connected to the heat source inlet of the reboiler (2). The heat pump is used to transport the gas phase generated by the dealcoholization tower (3) to the reboiler (2) as the heat source of the reboiler (2).

2. The ethylene glycol distillation system as described in claim 1, characterized in that, The reboiler (2) is externally connected to a condenser (4); The condenser (4) is connected to the heat source outlet of the reboiler (2) and is used to transport the gas-liquid mixture formed by the reboiler (2) after using the heat source to the condenser (4) for cooling.

3. The ethylene glycol distillation system as described in claim 2, characterized in that, The circulating water inlet temperature in the condenser (4) is 30°C.

4. The ethylene glycol distillation system as described in claim 1, characterized in that, The material level in the reboiler (2) and the liquid level in the ethylene glycol concentration tower (1) are at the same height.

5. The ethylene glycol distillation system as described in claim 1, characterized in that, The gas phase in the dealcohol tower (3) is pressurized by a heat pump to reach a gas phase temperature of 160°C.

6. The ethylene glycol distillation system as described in claim 1, characterized in that, The reboiler (2) is a thermosiphon reboiler.

7. The ethylene glycol distillation system as described in claim 1, characterized in that, Control valves are installed on the ethylene glycol concentration tower (1), reboiler (2), dealcoholization tower (3), and condenser (4).

8. The ethylene glycol distillation system as described in claim 7, characterized in that, Each control valve is fitted with a shock absorber.

Images