Method and system for improving light transmittance of coal ethylene glycol

Abstract

The invention belongs to the technical field of coal ethylene glycol, and relates to a method and system for improving the light transmittance of coal ethylene glycol, and the method comprises the following steps: in coal ethylene glycol multi-tower rectification, an auxiliary agent is supplemented into an ethylene glycol product tower through an auxiliary agent pipeline, the auxiliary agent is ethylene glycol, and the addition amount of the auxiliary agent is 1-2 L / h. According to the invention, the assistant is supplemented into the ethylene glycol product tower, so that the light transmittance of the ethylene glycol product is improved, the aldehyde content of the product is reduced, scaling and polymer generation in the ethylene glycol rectifying tower can be effectively inhibited, the quality of the ethylene glycol product is improved, the production cost is reduced, and the process is simple and has no residual risk.

Description

Technical Field

[0001] This invention belongs to the field of coal-to-ethylene glycol technology, and relates to a method and system for improving the light transmittance of coal-to-ethylene glycol. Background Technology

[0002] In coal-based ethylene glycol production, ethylene glycol distillation often employs a multi-tower system, consisting of a methanol recovery tower (#1), a methanol recovery tower (#2), a dehydration tower, a light alcohol removal tower (50), an ethylene glycol product tower (60), an ethylene glycol recovery tower (#1), an ethanol recovery tower (#2), and an aldehyde removal tower; this is also known as eight-tower distillation. To ensure ethylene glycol performance, the national standard GB / T4649-2018 requires that the ethylene glycol product have UV transmittance of ≥75%, 92%, and 99% at 220nm, 275nm, and 350nm UV values, respectively. However, in actual production, crude ethylene glycol contains impurities such as organic acids, aldehydes, and esters, which exhibit strong absorption peaks in UV light at 220nm or 275nm wavelengths, resulting in low UV transmittance of the ethylene glycol product. Consequently, during hydrogenation synthesis, the quality of ethylene glycol deteriorates, increasing the difficulty of subsequent ethylene glycol distillation, reducing the ethylene glycol product yield, and increasing ethylene glycol production costs.

[0003] Currently, to improve the UV transmittance of ethylene glycol products, chemical additives are added during the ethylene glycol distillation process to remove or convert impurities that affect transmittance; these chemical additives are resins (formaldehyde-removing resins and deesterifying resins). While existing methods can improve transmittance, they have the following problems:

[0004] (1) Since the resin relies on physical adsorption or chemical conversion, it needs to be replaced or regenerated when it reaches saturation, which makes the process complex and the production cost high.

[0005] (2) There is a risk of resin particles remaining. These resin particles may form tiny suspended matter in the ethylene glycol product, which can easily cause scaling or polymer formation in the ethylene glycol refining tower, resulting in high aldehyde content in the product, poor quality of the ethylene glycol product, and reduced light transmittance. Summary of the Invention

[0006] To address the technical problems associated with existing methods for improving the transmittance of ethylene glycol using resins, such as process complexity, high production costs, and residual risks, this invention provides a method and system for improving the transmittance of coal-derived ethylene glycol.

[0007] This invention involves adding an additive, namely ethylene glycol, to the ethylene glycol product column. The additive has the same composition as the final product, which not only improves the light transmittance of the ethylene glycol product and reduces the aldehyde content, but also effectively inhibits scaling and polymer formation in the ethylene glycol distillation column, thereby improving the quality of the ethylene glycol product, reducing production costs, and making the process simple, without residual risks, and safe and reliable.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for improving the light transmittance of coal-derived ethylene glycol includes the following steps:

[0010] In the multi-tower distillation of coal-to-ethylene glycol, an auxiliary agent, ethylene glycol, is added to the ethylene glycol product tower through an auxiliary agent pipeline at a rate of 1 L / h to 2 L / h.

[0011] Furthermore, the amount of additives added is regulated by an additive metering pump installed on the additive pipeline.

[0012] Further specified, the additives are supplied to the additive pipeline via additive storage tanks.

[0013] Furthermore, the liquid level in the additive storage tank should be controlled between 50% and 70%.

[0014] A system for improving the transmittance of ethylene glycol, used to implement the method for improving the transmittance of coal-derived ethylene glycol, includes an additive pipeline and an additive metering pump. The additive pipeline is connected to an ethylene glycol production unit and is used to add an additive, which is ethylene glycol, to the ethylene glycol production unit.

[0015] An additive metering pump, installed on the additive pipeline, is used to control the amount of additives added in the ethylene glycol production unit.

[0016] Furthermore, the system for improving the light transmittance of ethylene glycol also includes an additive storage tank; the additive storage tank is connected to the ethylene glycol production unit via an additive metering pump and additive pipelines.

[0017] Furthermore, the auxiliary agent storage tank is equipped with a level gauge.

[0018] Further specifying, the ethylene glycol production unit includes a light-light product removal tower, an ethylene glycol product tower feed pump, and an ethylene glycol product tower connected in sequence; the auxiliary agent pipeline is connected to the ethylene glycol product tower feed pump and the ethylene glycol product tower respectively.

[0019] Furthermore, the system for improving the transmittance of ethylene glycol also includes a calibration column connected to the additive metering pump, which is used to calibrate and detect the flow rate of the additive metering pump.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This invention involves adding an additive, ethylene glycol, to the ethylene glycol product column. The additive reacts with unsaturated trace impurities in the ethylene glycol product to form heavier components, which are then removed, thereby reducing impurity components in the ethylene glycol product. Simultaneously, the added additive also acts as an antioxidant. This improves the light transmittance of the ethylene glycol product, reduces its aldehyde content, and enhances its quality. The ethylene glycol additive is added directly to the distillation process via pipeline, making the operation simple, safe, and reliable.

[0022] 2. This invention adds ethylene glycol as an additive to the ethylene glycol product column. Since the additive has the same composition as the final product, there is no risk of residue. It can also effectively inhibit scaling and polymer formation in the ethylene glycol distillation column, improve the quality of ethylene glycol products, and reduce production costs.

[0023] 3. This invention adds an additive to the multi-tower distillation process of coal-to-ethylene glycol after the light component removal tower. This improves light transmittance and product quality while preventing the ethylene glycol additive from diluting the concentration of light components in the light component removal tower and affecting the reaction balance, thus avoiding excessive ethylene glycol content in the top light component product. This ensures the quality of the ethanol product in subsequent processes. Actual production operation has shown that adding the additive to the multi-tower distillation process of coal-to-ethylene glycol after the light component removal tower, at an ethylene glycol addition rate of 1L / h to 2L / h, results in the crude ethylene glycol from the side stream of the ethylene glycol product tower achieving an average transmittance of 79.84% at 220nm and an average transmittance of 82.77% at 275nm. The final ethylene glycol product has an average transmittance of 95%-96% and an aldehyde content ≤10ppm, thereby maximizing transmittance and the quality of the ethylene glycol product.

[0024] 4. In this invention, the liquid level in the auxiliary agent storage tank is adjusted to 50% to 70% when adding the auxiliary agent. This is because the ethylene glycol product tower is a negative pressure tower, and a liquid level of 50% to 70% can maintain a high liquid level, avoiding backflow that would allow air to enter the auxiliary agent pipeline and affect the continuous and stable addition of the auxiliary agent, thus ensuring the normal operation of the production process system.

[0025] 5. This invention connects a calibration column to the auxiliary metering pump, and uses the calibration column to calibrate and detect the flow rate of the auxiliary metering pump, so that ethylene glycol is added to the ethylene glycol production process with a precise flow rate, which greatly improves the light transmittance of ethylene glycol and the quality of the finished ethylene glycol product. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a system for improving the transmittance of ethylene glycol provided by the present invention;

[0027] in:

[0028] 10 - Additive pipeline; 20 - Additive metering pump; 30 - Additive storage tank; 40 - Level gauge; 50 - Light weight removal tower; 60 - Ethylene glycol product tower; 70 - Ethylene glycol product tower feed pump; 80 - Reflux pipeline. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. It should be noted that the technical terms used in this invention are for describing particular embodiments only and are not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this invention, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. "Upper," "lower," "left," "right," etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0031] In the existing coal-to-ethylene glycol multi-tower distillation process, the main processing steps in each tower are as follows:

[0032] (1) The crude methanol from the ethylene glycol synthesis process is separated in the No. 1 methanol recovery tower. After distillation, a small amount of methanol is taken out from the reflux tank to reduce the low-boiling-point ester impurities in the system. Refined methanol is taken out from the side stream. Ethylene glycol mixture containing a small amount of esters and methanol (i.e. crude ethylene glycol) is obtained from the bottom of the tower and sent to the No. 2 methanol recovery tower for further separation.

[0033] (2) The crude ethylene glycol from the ethylene glycol synthesis process separated by the No. 2 methanol recovery tower and the crude ethylene glycol from the No. 1 methanol recovery tower are distilled and collected from the reflux tank to obtain methanol with higher purity. The crude ethylene glycol obtained from the bottom of the tower is sent to the dehydration tower for further purification of ethylene glycol.

[0034] (3) The crude ethylene glycol from the No. 2 methanol recovery tower is separated by the dehydration tower. After distillation, the mixed alcohol ester aqueous solution containing a large amount of ethanol is collected from the reflux tank and sent to the No. 2 ethanol recovery tower. The ethylene glycol (crude ethylene glycol) with a higher content is obtained from the bottom of the tower and sent to the light alcohol removal tower for further purification of ethylene glycol.

[0035] (4) The crude ethylene glycol from the light-light separation tower and the dehydration tower is distilled and the crude ethylene glycol solution containing a large amount of butanediol is collected from the reflux tank and sent to the aldehyde removal tower; the ethylene glycol (crude ethylene glycol) with higher purity is obtained from the bottom of the tower and sent to the ethylene glycol product tower for further purification.

[0036] (5) The crude ethylene glycol from the light alcohol removal tower is distilled and then taken out of the reflux tank to the liquid phase hydrogenation reactor, or to the qualified ethylene glycol tank, or directly sent to the light alcohol removal tower for re-distillation; after distillation, polyester grade ethylene glycol is taken out from the side stream, and ethylene glycol containing heavy alcohol (crude ethylene glycol) is obtained from the bottom of the tower and sent to the No. 1 ethylene glycol recovery tower for further separation. The polyester grade ethylene glycol taken out from the side stream is cooled and then enters the refining tank. After impurity treatment, it is sent to the ethylene glycol metering tank for storage.

[0037] (6) The crude ethylene glycol from the ethylene glycol product tower is separated in the No. 1 ethylene glycol recovery tower. After distillation, industrial-grade ethylene glycol is collected from the reflux tank and sent to the liquid phase hydrogenation reactor, or to the qualified ethylene glycol tank. Crude ethylene glycol with a high diethylene glycol content is obtained from the bottom of the tower and sent to the heavy alcohol tank.

[0038] (7) The 2# ethanol recovery tower separates and dehydrates the mixed alcohol ester aqueous solution containing a large amount of ethanol. After distillation, a small amount of high-purity methanol is collected from the reflux tank and sent to the 1# methanol recovery tower; ethanol with a purity of more than 80% is collected from the side stream; and mixed alcohol ester with a high water content is obtained from the bottom of the tower and sent to the mixed alcohol ester tank.

[0039] (8) The crude ethylene glycol solution containing a large amount of butanediol from the light-light removal tower is separated by the aldehyde removal tower. After distillation, the crude ethylene glycol containing a large amount of butanediol is collected from the reflux tank. Ethylene glycol containing a small amount of butanediol is obtained from the bottom of the tower and sent to the reflux tank of the light-light removal tower for recovery.

[0040] Multi-tower distillation of coal-to-ethylene glycol is a mature existing technology, and the remaining processes will not be elaborated here. Towers #1 and #2 are both methanol recovery towers, and towers #1 and #2 are both ethanol recovery towers; the names #1 and #2 are used to distinguish the feed and distilled products. In the existing multi-tower distillation process of ethylene glycol, the ultraviolet transmittance of ethylene glycol decreases, resulting in poor distillation separation. Therefore, this invention proposes a method to improve the transmittance of ethylene glycol, namely, adding an additive (ethylene glycol) during the ethylene glycol distillation process, specifically between the light radical removal tower and the ethylene glycol product tower. This effectively improves product quality, transmittance, and yield; furthermore, it prevents the free radical conversion and decomposition in ethylene glycol from forming polymers, thus preventing crystallization and polymerization, and improving the operational efficiency of ethylene glycol distillation.

[0041] The method for improving the transmittance of ethylene glycol according to the present invention will be described in detail below with specific embodiments.

[0042] Example 1

[0043] To address the problems of decreased UV transmittance and poor distillation separation in existing ethylene glycol production processes, this embodiment provides a method for improving the transmittance of coal-derived ethylene glycol, comprising the following steps:

[0044] In the multi-tower distillation of ethylene glycol from coal, an additive, ethylene glycol, is added to the ethylene glycol product tower 60 at a rate of 1 L / h to 2 L / h. The flow rate can be 1 L / h, 1.2 L / h, 1.5 L / h, 1.8 L / h, or 2 L / h.

[0045] Preferably, an ethylene glycol product column feed pump 70 is installed between the ethylene glycol product column 60 and the light-weight product column 50. The ethylene glycol product column feed pump 70 is used to transport the bottom liquid of the light-weight product column 50 to the ethylene glycol product column 60. An auxiliary agent pipeline 10 is connected to the outlet pipeline of the ethylene glycol product column feed pump 70, that is, the pipeline between the ethylene glycol product column feed pump 70 and the ethylene glycol product column 60, for adding auxiliary agents to the ethylene glycol product column 60.

[0046] Preferably, in order to facilitate control of the amount of additives added, an additive metering pump 20 is installed on the additive pipeline 10.

[0047] Preferably, an auxiliary agent storage tank 30 is also provided, which is connected to the auxiliary agent metering pump 20. The auxiliary agent storage tank 30 is used to store the auxiliary agent ethylene glycol. In use, the auxiliary agent stored in the auxiliary agent storage tank 30 is pumped into the auxiliary agent pipeline 10 by the auxiliary agent metering pump 20, so that the auxiliary agent and the bottom liquid of the light removal tower 50 are sent to the ethylene glycol product tower 60 together.

[0048] Preferably, the liquid level in the additive storage tank 30 is above 50%, because the ethylene glycol product tower 60 is a negative pressure tower, which keeps the additive at a high liquid level to prevent backflow and allow air to enter the additive pipeline 10.

[0049] The following specific application examples illustrate the detailed process by which the present invention improves the light transmittance of coal-to-ethylene glycol.

[0050] In the 8-tower distillation process for preparing ethylene glycol, ethylene glycol is added to the auxiliary agent storage tank 30 at a level of 50%-70%. Then, the outlet pipeline of the ethylene glycol product tower feed pump 70 is connected to the auxiliary agent metering pump 20 and the auxiliary agent storage tank 30 via the auxiliary agent pipeline 10. The stroke of the auxiliary agent metering pump 20 is adjusted according to the transmittance of the ethylene glycol product to control the amount of supplementary glycol added, which is then delivered to the ethylene glycol product tower 60. Specifically, the ethylene glycol level in the auxiliary agent storage tank 30 is controlled at 50%, 55%, 60%, 65%, or 70%.

[0051] In this embodiment, the additive metering pump 20 is used to accurately deliver various additives. It is equipped with a calibration column, which is used to calibrate and test the flow rate of the additive metering pump 20 to ensure its metering accuracy. It should be noted that both the additive metering pump 20 and the calibration column are commercially available products, and their connection and installation are based on mature technologies in the field.

[0052] Specifically, adjust the stroke of the auxiliary metering pump 20 to 0%, open the inlet valve of the auxiliary metering pump 20, open the root valve of the calibration column at the inlet of the auxiliary metering pump 20, fill the calibration column with 100mL of liquid, close the inlet valve of the auxiliary metering pump 20, open the outlet valve of the auxiliary metering pump 20, start the auxiliary metering pump 20 to adjust the dosage of calibration auxiliary agent, and control the amount of auxiliary agent added to the ethylene glycol system.

[0053] In this embodiment, the operation steps for the calibration column on the additive metering pump 20 are as follows:

[0054] (1) Adjust the 20 stroke of the additive metering pump to 0%;

[0055] (2) At a flow rate of 1 L / h, it takes 6 minutes to precipitate 100 mL of the calibration column; at a flow rate of 1.5 L / h, it takes 4 minutes to precipitate 100 mL of the calibration column; at a flow rate of 2 L / h, it takes 3 minutes to precipitate 100 mL of the calibration column.

[0056] (3) After the calibration column is calibrated, open the inlet valve of the auxiliary metering pump 20 and close the root valve of the calibration column.

[0057] The following section uses our company's coal-to-ethylene glycol multi-tower distillation (i.e., eight-tower distillation) production as an example to improve the existing coal-to-ethylene glycol eight-tower distillation process. Ethylene glycol as an additive is added to the ethylene glycol product tower 60. Then, at different time points during operation, ethylene glycol product (or crude ethylene glycol product) is collected from the side stream of the ethylene glycol product tower 60, and its transmittance is tested. Specific data are shown in Tables 1, 2, and 3 below.

[0058] Table 1. Light transmittance of ethylene glycol product samples taken from the side of the tower at different time points during continuous operation without additives.

[0059]

[0060]

[0061] Table 2. Light transmittance of ethylene glycol product tower side at different time points during continuous operation with additives added at a rate of 1 L / h.

[0062]

[0063] Table 3. Light transmittance of ethylene glycol product from the tower side at different time points during continuous operation with additives added at 1.5 L / h.

[0064]

[0065] As shown in Table 1, when producing ethylene glycol using conventional multi-tower distillation, the crude ethylene glycol product collected from side 60 of the ethylene glycol product tower after continuous operation for a certain period of time has an average transmittance of 76.76% at 220 nm and an average transmittance of 77.6% at 275 nm.

[0066] As shown in Table 2, when ethylene glycol additive is added between ethylene glycol product tower 60 and light residue removal tower 50 at a flow rate of 1 L / h, the crude ethylene glycol product collected from the side stream of ethylene glycol product tower 60 has an average transmittance of 79.86% at 220 nm, which is 3.1% higher than that without additive; and an average transmittance of 80.77% at 275 nm, which is 3.17% higher than that without additive.

[0067] As shown in Table 3, when ethylene glycol additive is added between ethylene glycol product tower 60 and light residue removal tower 50 at a flow rate of 1.5 L / h, the crude ethylene glycol product collected from the side stream of ethylene glycol product tower 60 has an average transmittance of 82.77% at 220 nm, which is 6.01% higher than that without additive; and an average transmittance of 83.18% at 275 nm, which is 5.58% higher than that without additive.

[0068] In this embodiment, when the flow rate of the auxiliary agent diethanol was increased to 2L / h, the crude ethylene glycol product collected from the 60 side stream of the ethylene glycol product tower had an average transmittance of 84.69% at 220nm, which is 7.93% higher than that without the auxiliary agent; and an average transmittance of 84.07% at 275nm, which is 6.47% higher than that without the auxiliary agent.

[0069] The data above also shows that transmittance increases with flow rate, but the increase is smaller when the flow rate exceeds 2 L / h. Considering factors such as cost and efficiency, it is advisable to control the amount of ethylene glycol added to the additive within the range of 1 L / h to 2 L / h.

[0070] Further processing of the ethylene glycol (i.e. crude ethanol) collected from the side of the ethylene glycol product tower 60 in this embodiment, including subsequent separation, purification, and aldehyde removal, yields the finished ethylene glycol product. Its average transmittance at 220 nm is above 85%, and its average transmittance at 275 nm is 95%-96%, with an aldehyde content ≤10 ppm.

[0071] The above results indicate that by adding an additive between the light-light-removal tower 50 and the ethylene glycol product tower 60, the additive and the crude ethylene glycol from the light-light-removal tower 50 can simultaneously enter the ethylene glycol product tower 60, thereby increasing the transmittance of the crude ethylene glycol from the ethylene glycol product tower and the final ethylene glycol product. At the same time, it can effectively inhibit scaling and polymer formation in the ethylene glycol distillation tower, reduce aldehyde content, improve the quality of the ethylene glycol product, and reduce production costs.

[0072] Example 2

[0073] See Figure 1 This embodiment provides a system for improving the transmittance of ethylene glycol, used in the method of Example 1 to improve the transmittance of ethylene glycol. The system for improving the transmittance of ethylene glycol includes an additive line 10, an additive metering pump 20, and an additive storage tank 30.

[0074] The additive pipeline 10 is connected to the ethylene glycol production unit and is used to add additives to the ethylene glycol production unit. The additives are preferably ethylene glycol.

[0075] An additive metering pump 20 is installed on the additive pipeline 10 and is used to control the flow rate of additives added in the ethylene glycol production unit. Preferably, the flow rate is 1L / h to 2L / h, and the flow rate can be 1L / h, 1.2L / h, 1.5L / h, 1.8L / h, or 2L / h.

[0076] The auxiliary agent storage tank 30 is used for storing auxiliary agents, and the auxiliary agent storage tank 30 is connected to the ethylene glycol production unit through the auxiliary agent metering pump 20 and the auxiliary agent pipeline 10.

[0077] In this embodiment, a calibration column is connected to the additive metering pump 20 to calibrate and detect the flow rate of the additive metering pump 20, ensuring the stability and accuracy of the ethylene glycol addition flow rate.

[0078] In this embodiment, a level gauge 40 is also installed on the auxiliary agent storage tank 30 to monitor the liquid level of the auxiliary agent in the tank 30. Maintaining the liquid level between 50% and 70% ensures that the auxiliary agent storage tank 30 is at a high level, preventing backflow that could draw air into the auxiliary agent pipeline and affect the continuous and stable addition of the auxiliary agent. Specifically, the liquid level is controlled at 50%, 55%, 60%, 65%, or 70%.

[0079] In this embodiment, the ethylene glycol production unit includes a light-light product removal tower 50, an ethylene glycol product tower feed pump 70, and an ethylene glycol product tower 60 connected in sequence. One end of the auxiliary agent pipeline 10 is connected to the auxiliary agent storage tank 30, and the other end of the auxiliary agent pipeline 10 is connected to both the ethylene glycol product tower feed pump 70 and the ethylene glycol product tower 60. This allows the auxiliary agent pipeline 10 to connect to the ethylene glycol product tower 60 via the ethylene glycol product tower feed pump 70. Preferably, the bottom of the light-light product removal tower 50 is connected to the ethylene glycol product tower 60 via the ethylene glycol product tower feed pump 70. To improve the crude ethylene glycol separation efficiency of the light-light product removal tower 50, a reflux pipeline 80 is also provided. After passing through the ethylene glycol product tower feed pump 70, a portion of the liquid from the bottom of the light-light product removal tower 50 enters the ethylene glycol product tower 60 along with the auxiliary agent; the remaining portion flows back to the side of the light-light product removal tower 50 via the reflux pipeline 80, thereby improving the separation efficiency of the crude ethylene glycol and increasing the purity of the final product.

[0080] Preferably, there are two ethylene glycol product tower feed pumps 70, connected in parallel, with one as a backup. When one of the ethylene glycol product tower feed pumps 70 stops urgently, the system can be switched to the other in a timely manner to ensure normal system operation. The system for improving the transmittance of ethylene glycol in this embodiment operates in the same way as the method in Example 1.

[0081] It should be noted that all equipment components used in this invention are commercially available and conventional in the field, and these devices can meet the process requirements for temperature, pressure, and corrosion resistance during operation. Furthermore, the connection and installation methods of each component are conventional and known techniques in the field, and will not be described in detail here.

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the light transmittance of coal-based ethylene glycol, characterized in that, Includes the following steps: In the multi-tower distillation of coal-to-ethylene glycol, an additive is added to the ethylene glycol product tower (60) through the additive pipeline (10). The additive is ethylene glycol, and the amount of additive added is 1L / h to 2L / h.

2. The method for improving the light transmittance of coal-based ethylene glycol according to claim 1, characterized in that, The amount of additive added is adjusted by an additive metering pump (20) installed on the additive line (10).

3. The method for improving the light transmittance of coal-to-ethylene glycol according to claim 1, characterized in that, Additives are supplied to the additive pipeline (10) via the additive storage tank (30).

4. The method for improving the light transmittance of coal-to-ethylene glycol according to claim 3, characterized in that, The liquid level in the additive storage tank (30) is controlled at 50% to 70%.

5. A system for improving the transmittance of ethylene glycol, used to achieve the method for improving the transmittance of coal-derived ethylene glycol as described in claim 2, characterized in that, Includes an additive pipeline (10) and an additive metering pump (20). The additive pipeline (10) is connected to the ethylene glycol production unit and is used to add the additive ethylene glycol to the ethylene glycol production unit. An additive metering pump (20) is installed on the additive pipeline (10) to control the amount of additives added in the ethylene glycol production unit.

6. The system for improving the transmittance of ethylene glycol according to claim 5, characterized in that, The system for improving the light transmittance of ethylene glycol also includes an additive storage tank (30); the additive storage tank (30) is connected to the ethylene glycol production unit via an additive metering pump (20) and an additive pipeline (10).

7. The system for improving the transmittance of ethylene glycol according to claim 6, characterized in that, A level gauge (40) is installed on the auxiliary agent storage tank (30).

8. The system for improving the transmittance of ethylene glycol according to claim 6, characterized in that, The ethylene glycol production unit includes a light-removal tower (50), an ethylene glycol product tower feed pump (70), and an ethylene glycol product tower (60) connected in sequence; the auxiliary agent pipeline (10) is connected to the ethylene glycol product tower feed pump (70) and the ethylene glycol product tower (60) respectively.

9. The system for improving the transmittance of ethylene glycol according to claim 5, characterized in that, The system for improving the transmittance of ethylene glycol also includes a calibration column connected to the additive metering pump (20), which is used to calibrate and detect the flow rate of the additive metering pump (20).

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