A yellow glycerin impurity removal system

Abstract

The utility model relates to a kind of yellow glycerol impurity removal systems, and the yellow glycerol impurity removal system includes yellow glycerol storage tank (1), preheater (3), rectifying tower (4), condenser (5), cooler (6) and condensate tank (7) etc.;The yellow glycerol impurity removal system is contacted by stripping steam and yellow glycerol in rectifying tower, and the efficient transfer of impurity from liquid phase to gas phase is realized.Test results show that the yellow glycerol impurity removal system of the utility model can improve the purity of yellow glycerol from 97% to more than 99%, and the saponification equivalent is reduced from 35mmol / 100g to less than 3mmol / 100g.The yellow glycerol impurity removal system of the utility model has the advantages of stable operation, easy maintenance, low energy consumption and high efficiency.

Description

Technical Field

[0001] This utility model belongs to the field of chemical equipment separation technology. More specifically, this utility model relates to a system for removing impurities from yellow glycerin. Background Technology

[0002] Yellow glycerin is produced during the refining process of glycerin. Its glycerin content is below 97%, and its saponification equivalent is above 20 mmol / 100g. It still contains a small amount of water and organic impurities, which can affect the quality and application range of glycerin products. Therefore, removing impurities from yellow glycerin to improve its purity is of great significance for meeting the needs of the high-end market and increasing the added value of the product.

[0003] Currently, although some methods and equipment exist for removing impurities from glycerol on the market, they generally suffer from low efficiency, high energy consumption, and complex operation. Some of these methods require multiple distillation and extraction steps, which not only increases production costs but may also introduce new impurities. Some impurity removal equipment has complex structures, is difficult to maintain, and requires highly skilled operators. Therefore, developing a highly efficient, energy-saving, and easy-to-operate glycerol impurity removal system has become an urgent problem to be solved in the field of chemical equipment separation technology.

[0004] In order to overcome some of the shortcomings of the existing technology, the inventors conducted a large number of experiments and research analyses based on the summary of the existing technology, and finally completed this utility model. Summary of the Invention

[0005] [Technical problem to be solved] The purpose of this invention is to provide a system for removing impurities from yellow glycerin.

[0006] Technical solution This utility model is achieved through the following technical solution.

[0007] This utility model relates to a yellow glycerin impurity removal system, which includes a yellow glycerin storage tank 1, a preheater 3, a distillation column 4, a condenser 5, a cooler 6, and a condensate tank 7. Yellow glycerin from outside the system is connected to the yellow glycerin storage tank inlet 11 located at the upper part of the yellow glycerin storage tank 1 through a pipeline, while the yellow glycerin storage tank outlet 12 located at the lower part of the yellow glycerin storage tank 1 is connected to the yellow glycerin transfer pump 2 and the preheater inlet 31 located at one end of the preheater 3 through a pipeline. The preheater outlet 32 ​​located at the other end of the preheater 3 is connected to the distillation column inlet 41 located in the middle of the distillation column 4 through a pipeline. A refined glycerin inlet 33 and a refined glycerin outlet 34 are arranged opposite each other near the preheater outlet 32. A distillation column outlet 43 is provided at the bottom of the distillation column 4. It is connected to the refined glycerin inlet 33 via a pipeline to the refined glycerin delivery pump 9. The refined glycerin outlet 34 discharges refined glycerin through a pipeline. A distillation column vapor outlet 42 is provided at the top of the distillation column 4. It is connected to the distillation column vapor inlet 51 located at one end of the condenser 5 via a pipeline. A first thermometer mounting port 48 and a second thermometer mounting port 49 are provided at the upper and middle parts of the distillation column 4, respectively. A first liquid level gauge mounting port 46 and a second liquid level gauge mounting port 47 are provided on the same side at the lower part of the distillation column 4. Liquid level gauges 411 are installed at the first liquid level gauge mounting port 46 and the second liquid level gauge mounting port 47. A stripping steam inlet 44 is provided on the opposite side of them. A third thermometer mounting port 410 is provided below the stripping steam inlet 44. A distillation column vapor inlet 51 is provided at one end of the condenser 5. A condensate tank condensate inlet 53 and a condensate tank condensate outlet 54 are also provided at the top of the same end. The former is connected to the condensate tank outlet 72 via a pipe and a reflux pump 8, while the latter is connected to the condensate reflux port 45 via a pipe. A condensate outlet 52 is provided at the other end of the condenser 5. It is connected to the condensate inlet 61 at one end of the cooler 6 via a pipe, while the cooling condensate outlet 62 at the other end of the cooler 6 is connected to the condensate tank inlet 71. A cooler vapor outlet 65 provided at the other end of the cooler 6 is connected to the condensate tank vapor outlet 74 provided at one end of the condensate tank 7, and is open to the outside. A refrigerant inlet 63 and a refrigerant outlet 64 are provided at the top of the cooler 6 near the cooler vapor outlet 65. In the condensate tank 7, a condensate tank outlet 72 and a condensate discharge outlet 73 are respectively provided at both ends on the side opposite to the condensate tank gas phase outlet 74; the condensate tank outlet 72 is connected to the reflux pump 8, while the condensate discharge outlet 73 is open to the outside.

[0008] According to a preferred embodiment of the present invention, the distillation column 4 is a floating valve plate or sieve plate type column.

[0009] According to another preferred embodiment of the present invention, the number of trays in the distillation column 4 is 20 to 40.

[0010] According to another preferred embodiment of the present invention, the tray opening ratio of the distillation column 4 is 5~20%.

[0011] According to another preferred embodiment of the present invention, the height to diameter ratio of the distillation column 4 is 8~12:1.

[0012] According to another preferred embodiment of the present invention, the upper part of the distillation column 4 is a packing layer with a height of 1 to 3 m.

[0013] According to another preferred embodiment of the present invention, the preheater 3, the condenser 5 and the cooler 6 are shell-and-tube heat exchangers.

[0014] According to another preferred embodiment of the present invention, the yellow glycerin delivery pump 2, the reflux pump 8, and the refined glycerin delivery pump 9 are positive displacement pumps.

[0015] According to another preferred embodiment of the present invention, the thermometer installed in the thermometer mounting port is a thermocouple thermometer.

[0016] According to another preferred embodiment of the present invention, the level gauge installed in the level gauge mounting port is a magnetic float level gauge or a differential pressure level gauge.

[0017] The present invention will now be described in more detail.

[0018] This utility model relates to a yellow glycerin impurity removal system, the specific structure of which is shown in the appendix. Figure 1 .

[0019] The impurity removal system for yellow glycerin of this utility model includes a yellow glycerin storage tank 1, a preheater 3, a distillation column 4, a condenser 5, a cooler 6, and a condensate tank 7; The yellow glycerin from outside the boundary is connected to the yellow glycerin storage tank inlet 11 located at the top of the yellow glycerin storage tank 1 through a pipeline, while the yellow glycerin storage tank outlet 12 located at the bottom of the yellow glycerin storage tank 1 is connected to the yellow glycerin transfer pump 2 and the preheater inlet 31 located at one end of the preheater 3 through a pipeline. The preheater outlet 32 ​​located at the other end of the preheater 3 is connected to the distillation column inlet 41 located in the middle of the distillation column 4 through a pipeline. The refined glycerin inlet 33 and the refined glycerin outlet 34 are set opposite to each other at the end near the preheater outlet 32. The yellow glycerin storage tank 1 used in this utility model has a yellow glycerin storage tank inlet 11 at the upper part of the tank body and a yellow glycerin storage tank outlet 12 at the lower part of the tank body. It is a chemical material storage tank commonly used in the field of chemical technology.

[0020] The glycerin transfer pump 2 used in this invention is a positive displacement pump. This type of pump has advantages such as stable flow rate, small pressure fluctuations, and resistance to contamination of the transported medium. It ensures the stable and reliable operation of the glycerin impurity removal system and also has strong self-priming capability, adapting to the transport requirements under different working conditions. The positive displacement pump used in this invention is a screw pump or a rotary pump, which are currently available on the market. For example, the screw pump sold by Shanghai Sunshine Pump Industry Manufacturing Co., Ltd. under the trade name G-type single screw pump, and the rotary pump sold by Qingdao Luode General Machinery Equipment Co., Ltd. under the trade name cam rotor pump. The reflux pump 8 and the refined glycerin transfer pump 9 used below are also positive displacement pumps, and will not be described further below.

[0021] The preheater 3 used in this invention primarily functions to preheat the yellow glycerin entering the system, bringing it to a suitable temperature. Preheating effectively improves the efficiency of subsequent impurity removal and reduces energy consumption. Simultaneously, the preheater employs a highly efficient heat transfer structure to ensure uniform heating of the yellow glycerin, preventing localized overheating that could alter its properties and ensuring stable and efficient operation of the yellow glycerin impurity removal system.

[0022] The preheater 3 has a preheater inlet 31 at one end, which is connected to the yellow glycerin transfer pump 2 through a pipeline, and a preheater outlet 32 ​​at the other end, which is connected to the distillation column inlet 41 located in the middle of the distillation column 4 through a pipeline.

[0023] A refined glycerin inlet 33 and a refined glycerin outlet 34 are provided opposite to each other at one end near the preheater outlet 32; the refined glycerin discharged from the distillation column outlet 43 located at the bottom of the distillation column 4 is sent to the refined glycerin inlet 33 through a pipeline, and the refined glycerin is preheated in the preheater 3 and then discharged from the refined glycerin outlet 34. The preheater 3 used in this invention is a shell-and-tube heat exchanger, which has advantages such as compact structure, high heat transfer efficiency, and high operational flexibility, and can meet the high heat exchange requirements of the yellow glycerin impurity removal system. This invention uses a shell-and-tube heat exchanger to achieve efficient heat recovery and full utilization, reducing energy consumption and improving the overall economy of the system. The shell-and-tube heat exchanger preheater 3 is a heat exchange device well-known to engineers in this field and is a product currently available on the market, such as the shell-and-tube heat exchanger sold by Xiong Yu Industrial Equipment (Jiangsu) Co., Ltd. under the trade name "Tube Heat Exchanger". The condenser 5 and cooler 6 used below are also shell-and-tube heat exchangers, and will not be described further below.

[0024] The main function of the distillation column 4 used in this invention in the yellow glycerin impurity removal system is to separate impurities from the yellow glycerin through distillation, thereby improving the purity of the yellow glycerin. The distillation column has a specific tray structure that provides ample contact area between the gas and liquid phases, allowing the refined glycerin to exchange heat and mass with the descending condensate during its ascent, thus achieving impurity separation and glycerin purification. Simultaneously, the distillation column is also equipped with a high-efficiency reboiler and condenser to ensure the stability and efficiency of the distillation process.

[0025] The distillation column 4 used in this invention is a plate column with a floating valve plate or perforated sieve plate structure. A packing layer is provided in the upper part of the distillation column 4, and a floating valve plate or perforated sieve plate is installed below the packing layer. The floating valve plate is a plate with a valve plate structure that can float up and down; the perforated sieve plate is a plate with a uniformly distributed sieve hole structure. These plates are arranged at certain intervals within the column, forming a multi-stage plate structure. These plates can effectively increase the gas-liquid two-phase contact area and contact time, thereby enhancing the mass transfer process and improving the impurity removal efficiency.

[0026] This invention uses a distillation column with 20 to 40 floating valve plates or perforated sieve plates. If the number of floating valve plates or perforated sieve plates is less than 20, the contact between the gas and liquid phases in the column will be insufficient, the mass transfer process will be incomplete, leading to a decrease in impurity removal efficiency and making it difficult to achieve the desired improvement in the purity of glycerin. If the number of floating valve plates or perforated sieve plates is more than 40, although it can increase the gas-liquid contact to a certain extent, it will increase the system resistance, resulting in increased energy consumption and increased equipment manufacturing costs, which is not conducive to the economical operation of the system. Therefore, a number of floating valve plates or perforated sieve plates of 20 to 40 is reasonable. The opening ratio of the valve plate or sieve plate in the distillation column is 5-20%. If the opening ratio is less than 5%, the resistance to steam passage will be too high, resulting in poor stripping effect and insufficient removal of impurities from the glycerol. If the opening ratio is greater than 20%, the liquid layer of glycerol on the plate will be too thin, resulting in insufficient contact time between the stripping steam and the glycerol, which will also affect the impurity removal efficiency. Therefore, an opening ratio of 5-20% is suitable, ensuring smooth steam passage while allowing a uniform liquid layer of glycerol to form on the plate, ensuring sufficient contact between the stripping steam and the glycerol, and efficiently stripping impurities to the top of the column.

[0027] The distillation column 4 used in this invention has a packing layer at its top. This packing layer further increases the contact area between the gas and liquid phases, prolongs the contact time, and thus enhances the mass transfer effect. Furthermore, the packing layer can disperse and redistribute the rising vapor, making the contact between the vapor and the glycerin more uniform, improving the uniformity and stability of impurity removal. This packing layer is a packing layer with a regular geometric arrangement of wire mesh, corrugated plates, or grid packing. The thickness of this packing layer is 1-3 m. If the thickness of the packing layer is less than 1 m, the further separation and purification effect of the gas and liquid is limited, making it difficult to effectively retain trace impurities that may be entrained in the glycerin. If the height of the packing layer is greater than 3 m, although it can enhance the separation effect, it will increase the equipment resistance, leading to increased system energy consumption, and may also cause operational problems such as flooding, affecting system stability. Therefore, a thickness of 1-3 m is appropriate, ensuring both good separation effect and maintaining efficient and stable system operation. This packing layer is installed inside the distillation column 4 perpendicular to the column wall.

[0028] This invention uses a distillation column 4 with a height-to-diameter ratio of 8 to 12:1. If the ratio is less than 8:1, the gas-liquid distribution within the column will be uneven, leading to decreased mass transfer efficiency and affecting impurity removal. If the ratio is greater than 12:1, the column will be too tall, increasing manufacturing costs and potentially causing operational instability, increased energy consumption, and higher maintenance complexity. Therefore, a height-to-diameter ratio of 8 to 12:1 for the distillation column 4 is suitable.

[0029] The distillation column 4 used in this utility model is a product currently sold on the market, such as the plate column with floating valve plate sold by Jiangsu Xiede Energy Saving Technology Co., Ltd. under the trade name Distillation Column, and the plate column with sieve plate structure sold by Wuxi Hongdinghua Chemical Equipment Co., Ltd. under the trade name Distillation Column.

[0030] A distillation column outlet 43 is provided at the bottom of the distillation column 4. It is connected to the refined glycerin inlet 33 via a pipeline to the refined glycerin delivery pump 9. The refined glycerin outlet 34 discharges refined glycerin through a pipeline. A distillation column vapor outlet 42 is provided at the top of the distillation column 4. It is connected to the distillation column vapor inlet 51 located at one end of the condenser 5 via a pipeline. A first thermometer mounting port 48 and a second thermometer mounting port 49 are provided at the upper and middle parts of the distillation column 4, respectively. A first liquid level gauge mounting port 46 and a second liquid level gauge mounting port 47 are provided on the same side at the lower part of the distillation column 4. Liquid level gauges 411 are installed at the first liquid level gauge mounting port 46 and the second liquid level gauge mounting port 47. A stripping steam inlet 44 is provided on the opposite side of them. A third thermometer mounting port 410 is provided below the stripping steam inlet 44. The thermometers installed in these thermometer mounting ports are all thermocouple thermometers currently available on the market. The level gauges installed in the level gauge mounting ports are magnetic float level gauges or differential pressure level gauges, such as the magnetic float level gauges sold by Shanghai Sipai Electronic Technology Co., Ltd. under the trade name Magnetic Float Level Gauge, and the differential pressure level gauges sold by Tianjin Huatai Tianke Electronic Technology Co., Ltd. under the trade name Differential Pressure Level Gauge.

[0031] The condenser 5 used in this invention plays a key role in the impurity removal system of yellow glycerin by cooling and liquefying the vapor generated during the distillation of yellow glycerin, thus converting it back into a liquid state. By controlling the reflux ratio of the condensate, the purity of yellow glycerin can be improved.

[0032] A distillation column vapor inlet 51 is provided at one end of the condenser 5. A condensate tank condensate inlet 53 and a condensate tank condensate outlet 54 are also provided at the top of the same end. The former is connected to the condensate tank outlet 72 via a pipe and a reflux pump 8, while the latter is connected to the condensate reflux port 45 via a pipe. A condensate outlet 52 is provided at the other end of the condenser 5. It is connected to the condensate inlet 61 at one end of the cooler 6 via a pipe, while the cooling condensate outlet 62 at the other end of the cooler 6 is connected to the condensate tank inlet 71. A cooler vapor outlet 65 provided at the other end of the cooler 6 is connected to the condensate tank vapor outlet 74 provided at one end of the condensate tank 7, and is open to the outside. A refrigerant inlet 63 and a refrigerant outlet 64 are provided at the top of the cooler 6 near the cooler vapor outlet 65. In the condensate tank 7, a condensate tank outlet 72 and a condensate discharge outlet 73 are respectively provided at both ends on the side opposite to the condensate tank gas phase outlet 74; the condensate tank outlet 72 is connected to the reflux pump 8, while the condensate discharge outlet 73 is open to the outside.

[0033] The condensate tank 7 used in this utility model is a tank with a hollow structure. It is a product currently sold on the market, such as the product sold by Shanghai Xiongyu Machinery Equipment Co., Ltd. under the trade name stainless steel storage tank.

[0034] The yellow glycerin used in this invention was provided by Ningbo Huanyang New Material Co., Ltd. and Fujian Huanyang New Material Co., Ltd.

[0035] According to the analytical method of GB / T13206-2022, the glycerol content of this yellow glycerin is determined to be 96.0%~97.0% by weight. The refined glycerin obtained by using the yellow glycerin impurity removal system of this invention has a glycerin content of 99.0% or more by weight. According to the analytical method of GB / T13206-2022, the saponification equivalent of this yellow glycerol is determined to be above 35.2 mmol / 100g.

[0036] The saponification equivalent of refined glycerol obtained by using the yellow glycerol impurity removal system of this invention is less than 2.6 mmol / 100g.

[0037] [Beneficial Effects] This invention relates to a system for removing impurities from yellow glycerol. This system achieves efficient transfer of impurities from the liquid phase to the gas phase through countercurrent contact between stripping steam and yellow glycerol within a distillation column. Experimental results show that this system can increase the purity of yellow glycerol from below 97% to above 99%, and reduce the saponification equivalent from 35 mmol / 100g to below 3 mmol / 100g. This system offers significant advantages such as stable operation, simple maintenance, low energy consumption, and high efficiency. [Attached Image Description] Figure 1 This is a schematic diagram of the structure of the yellow glycerin impurity removal system of this utility model; In the picture: 1-Glycerin storage tank; 11-Glycerin storage tank inlet; 12-Glycerin storage tank outlet; 2-Glycerin transfer pump; 3-Preheater; 31-Preheater inlet; 32-Preheater outlet; 33-Refined glycerin inlet; 34-Refined glycerin outlet; 4-Distillation column; 41-Distillation column inlet; 42-Distillation column vapor outlet; 43-Distillation column outlet; 44-Stripping steam inlet; 45-Condensate reflux port; 46-First level gauge installation port; 47-Second level gauge installation port; 48-First thermometer installation port; 49-Second thermometer installation port; 41 0 - Third thermometer installation port; 411 - Liquid level gauge; 5 - Condenser; 51 - Distillation column vapor inlet; 52 - Condensate outlet; 53 - Condensate tank condensate inlet; 54 - Condensate tank condensate outlet; 6 - Cooler; 61 - Condensate inlet; 62 - Cooling condensate outlet; 63 - Refrigerant inlet; 64 - Refrigerant outlet; 65 - Cooler vapor outlet; 7 - Condensate tank; 71 - Condensate tank inlet; 72 - Condensate tank outlet; 73 - Condensate discharge outlet; 74 - Condensate tank vapor outlet; 8 - Reflux pump; 9 - Refined glycerin transfer pump.

Detailed Implementation Methods

[0038] Example 1: The present invention's yellow glycerin impurity removal system The implementation method of this embodiment is as follows: The impurity removal system for yellow glycerin includes a yellow glycerin storage tank 1, a preheater 3, a distillation column 4, a condenser 5, a cooler 6, and a condensate tank 7. Yellow glycerin from outside the system is connected to the yellow glycerin storage tank inlet 11 located at the top of the yellow glycerin storage tank 1 via a pipeline. The yellow glycerin storage tank outlet 12 located at the bottom of the yellow glycerin storage tank 1 is connected to the yellow glycerin transfer pump 2 of the rotary pump via a pipeline to the preheater inlet 31 located at one end of the shell-and-tube heat exchanger preheater 3. The preheater outlet 32 ​​located at the other end of the preheater 3 is connected to the distillation column inlet 41 located in the middle of the distillation column 4 via a pipeline. A refined glycerin inlet 33 and a refined glycerin outlet 34 are arranged opposite each other near the preheater outlet 32. Distillation column 4 is a plate column with a floating valve plate or sieve plate structure. Distillation column 4 has a 1.6m thick metal wire mesh packing layer in the upper part of the column body, and floating valve plates are installed below the packing layer. It has 26 plates and an opening ratio of 15%. The height to diameter ratio of distillation column 4 is 8:1.

[0039] A distillation column outlet 43 is provided at the bottom of the distillation column 4. It is connected to the refined glycerol inlet 33 via a pipeline to the rotary pump refined glycerol transfer pump 9. The refined glycerol outlet 34 discharges refined glycerol through a pipeline. A distillation column vapor outlet 42 is provided at the top of the distillation column 4. It is connected to the distillation column vapor inlet 51 located at one end of the shell-and-tube heat exchanger condenser 5 via a pipeline. A first thermometer mounting port 48 and a second thermometer mounting port 49 are provided at the upper and middle parts of the distillation column 4, respectively. A first level gauge mounting port 46 and a second level gauge mounting port 47 are provided on the same side at the lower part of the distillation column 4. A magnetic level gauge 411, sold by Shanghai Sipai Electronic Technology Co., Ltd. under the trade name Magnetic Flip Level Gauge, is provided between the first level gauge mounting port 46 and the second level gauge mounting port 47. A stripping steam inlet 44 is provided on the opposite side of them. A third thermometer mounting port 410 is provided below the stripping steam inlet 44. The first thermometer installed in the first thermometer mounting port 48, the second thermometer installed in the second thermometer mounting port 49, and the third thermometer installed in the third thermometer mounting port 410 have detection temperatures of 130℃, 150℃, and 170℃, respectively. The magnetic float level gauge installed at the first level gauge installation port 46 and the second level gauge installation port 47 detects a liquid level of 75.6%. A distillation column vapor inlet 51 is provided at one end of the condenser 5 of the shell-and-tube heat exchanger. A condensate inlet 53 and a condensate outlet 54 are also provided at the top of the same end. The former is connected to the condensate outlet 72 of the condensate tank via a pipe to the rotor pump reflux pump 8, while the latter is connected to the condensate reflux port 45 via a pipe. A condensate outlet 52 is provided at the other end of the condenser 5. It is connected to the condensate inlet 61 at one end of the cooler 6 of the shell-and-tube heat exchanger via a pipe. The cooling condensate outlet 62 at the other end of the cooler 6 is connected to the condensate tank inlet 71. A cooler vapor outlet 65 provided at the other end of the cooler 6 is connected to the condensate tank vapor outlet 74 provided at one end of the condensate tank 7, and is open to the outside. A refrigerant inlet 63 and a refrigerant outlet 64 are provided at the top of the cooler 6 near the cooler vapor outlet 65. In the condensate tank 7, a condensate tank outlet 72 and a condensate discharge outlet 73 are respectively provided at both ends on the side opposite to the condensate tank gas phase outlet 74; the condensate tank outlet 72 is connected to the rotor pump return pump 8, while the condensate discharge outlet 73 is open to the outside.

[0040] The results of testing the glycerol content of yellow glycerol, the glycerol content of refined glycerol, and the saponification equivalent of yellow glycerol and refined glycerol according to the method described in this application are listed in Table 1 below.

[0041] Example 2: The present invention's yellow glycerin impurity removal system The implementation method of this embodiment is the same as that of Embodiment 1, except that the yellow glycerin from outside the industry is produced by Ningbo Huanyang New Material Co., Ltd.; the distillation column 4 has a 1.0m thick corrugated packing layer in the upper part of the column body, and a sieve plate is installed below the packing layer. The number of plates is 40, and its opening ratio is 5%. The height to diameter ratio of the distillation column 4 is 10:1; the yellow glycerin transfer pump 2 is a screw pump, the reflux pump 8 is a screw pump; the refined glycerin transfer pump 9 is a rotary pump; the detection temperatures of the first thermometer, the second thermometer, and the third thermometer are 120℃, 140℃, and 165℃, respectively; the liquid level detected by the differential pressure level gauge is 78.8%; The glycerol content of yellow glycerol, the glycerol content of refined glycerol, and the saponification equivalent of yellow glycerol and refined glycerol were tested according to the method described in this application. The test results are listed in Table 1 below.

[0042] Example 3: The present invention's yellow glycerin impurity removal system The implementation method of this embodiment is the same as that of Embodiment 1, except that the yellow glycerin from outside the industry is produced by Ningbo Huanyang New Material Co., Ltd.; the distillation column 4 has a 3.0m thick grid packing layer in the upper part of the column body, and a floating valve plate is installed below the packing layer. The number of plates is 20, and its opening ratio is 20%. The height to diameter ratio of the distillation column 4 is 12:1; the yellow glycerin transfer pump 2 is a screw pump, the reflux pump 8 is a rotary pump; the refined glycerin transfer pump 9 is a screw pump; the detection temperatures of the first thermometer, the second thermometer, and the third thermometer are 110℃, 130℃, and 150℃, respectively; the liquid level detected by the differential pressure level gauge is 82.1%; The glycerol content of yellow glycerol, the glycerol content of refined glycerol, and the saponification equivalent of yellow glycerol and refined glycerol were tested according to the method described in this application. The test results are listed in Table 1 below.

[0043] Example 4: The present invention's yellow glycerin impurity removal system The implementation method of this embodiment is the same as that of Embodiment 1, except that the yellow glycerin from outside the industry is produced by Ningbo Huanyang New Material Co., Ltd.; the distillation column 4 has a 2.4m thick corrugated packing layer in the upper part of the column body, and a sieve plate is installed below the packing layer. The number of plates is 34, and the opening ratio is 10%. The height to diameter ratio of the distillation column 4 is 10:1; the yellow glycerin transfer pump 2 is a rotary pump, the reflux pump 8 is a screw pump; the refined glycerin transfer pump 9 is a screw pump; the detection temperatures of the first thermometer, the second thermometer, and the third thermometer are 115℃, 136℃, and 155℃, respectively; the liquid level detected by the magnetic float level gauge is 80.5%; The glycerol content of yellow glycerol, the glycerol content of refined glycerol, and the saponification equivalent of yellow glycerol and refined glycerol were tested according to the method described in this application. The test results are listed in Table 1 below.

[0044] Table 1: Implementation Results of Examples 1-4 The results listed in Table 1 clearly show that the yellow glycerol treated with the present invention's yellow glycerol impurity removal system has a stable glycerol content of over 99%, and the saponification equivalent is significantly reduced to below 3 mmol / 100g. This fully demonstrates the excellent performance of the present invention's yellow glycerol impurity removal system in removing impurities and improving glycerol purity.

Claims

1. A system for removing impurities from glycerin, comprising a glycerin storage tank (1), a preheater (3), a distillation column (4), a condenser (5), a cooler (6), and a condensate tank (7); characterized in that... The yellow glycerin from outside the boundary is connected to the yellow glycerin storage tank inlet (11) located at the top of the yellow glycerin storage tank (1) through a pipeline, while the yellow glycerin storage tank outlet (12) located at the bottom of the yellow glycerin storage tank (1) is connected to the yellow glycerin transfer pump (2) and the preheater inlet (31) located at one end of the preheater (3) through a pipeline. The preheater outlet (32) located at the other end of the preheater (3) is connected to the distillation column inlet (41) located in the middle of the distillation column (4) through a pipeline. The refined glycerin inlet (33) and the refined glycerin outlet (34) are set opposite to each other at the end near the preheater outlet (32). A distillation column outlet (43) is provided at the bottom of the distillation column (4), which is connected to the refined glycerin inlet (33) via a pipeline to the refined glycerin delivery pump (9), and the refined glycerin outlet (34) discharges refined glycerin via a pipeline; a distillation column vapor outlet (42) is provided at the top of the distillation column (4), which is connected to the distillation column vapor inlet (51) located at one end of the condenser (5) via a pipeline; a first thermometer installation port (48) and a second thermometer installation port (49) are provided at the upper and middle parts of the distillation column (4), respectively; a first liquid level gauge installation port (46) and a second liquid level gauge installation port (47) are provided on the same side of the lower part of the distillation column (4), and a liquid level gauge (411) is installed at the first liquid level gauge installation port (46) and the second liquid level gauge installation port (47); a stripping steam inlet (44) is provided on the opposite side of them; and a third thermometer installation port (410) is provided below the stripping steam inlet (44); A distillation column vapor inlet (51) is provided at one end of the condenser (5), and a condensate tank condensate inlet (53) and a condensate tank condensate outlet (54) are respectively provided at the top of the same end. The former is connected to the condensate tank outlet (72) through a pipe and a reflux pump (8), while the latter is connected to the condensate reflux port (45) through a pipe. A condensate outlet (52) is provided at the other end of the condenser (5), which is connected to the condensate inlet (61) at one end of the cooler (6) through a pipe, while the cooling condensate outlet (62) at the other end of the cooler (6) is connected to the condensate tank inlet (71). A cooler vapor outlet (65) provided at the other end of the cooler (6) is connected to the condensate tank vapor outlet (74) provided at one end of the condensate tank (7), and is open to the outside. A refrigerant inlet (63) and a refrigerant outlet (64) are provided at the top of the cooler (6) near the cooler vapor outlet (65). In the condensate tank (7), a condensate tank outlet (72) and a condensate discharge outlet (73) are respectively provided at both ends on the side opposite to the condensate tank gas phase outlet (74); the condensate tank outlet (72) is connected to the reflux pump (8), while the condensate discharge outlet (73) is connected to the outside.

2. The yellow glycerin impurity removal system according to claim 1, characterized in that... Distillation column (4) is a type of plate column with floating valve plate or perforated plate.

3. The yellow glycerin impurity removal system according to claim 1 or 2, characterized in that... The number of trays in the distillation column (4) is 20 to 40.

4. The yellow glycerin impurity removal system according to claim 1 or 2, characterized in that... The tray opening ratio of the distillation column (4) is 5~20%.

5. The yellow glycerin impurity removal system according to claim 1, characterized in that... The ratio of the height to the diameter of the distillation column (4) is 8~12:

1.

6. The yellow glycerin impurity removal system according to claim 1, characterized in that... The upper part of the distillation column (4) is a packing layer with a height of 1~3m.

7. The yellow glycerin impurity removal system according to claim 1, characterized in that... The preheater (3), condenser (5) and cooler (6) are shell-and-tube heat exchangers.

8. The yellow glycerin impurity removal system according to claim 1, characterized in that... The yellow glycerin transfer pump (2), the reflux pump (8) and the refined glycerin transfer pump (9) are positive displacement pumps.

9. The yellow glycerin impurity removal system according to claim 1, characterized in that... The thermometer installed in the thermometer mounting port is a thermocouple thermometer.

10. The yellow glycerin impurity removal system according to claim 1, characterized in that... The level gauge installed in the level gauge mounting port is a magnetic float level gauge or a differential pressure level gauge.

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