Glycerol distillation fractionation apparatus and method of use thereof

Abstract

The present application relates to the technical field of glycerol distillation, and discloses a glycerol distillation salt separation device and an application method thereof. The device comprises a salt separation assembly and a salt storage assembly. The salt separation assembly comprises a tank body and a feeding member in the tank body. The bottom of the tank body is provided with a sedimentation channel, and the sedimentation channel is in communication with the top of the salt storage assembly. The device reduces the influence of fluid disturbance on the sedimentation and salt separation of salt-containing crude glycerol through the salt separation assembly, the salt storage assembly and the sedimentation channel in communication with the two, thereby significantly improving the salt separation efficiency. Meanwhile, the tank body is divided into a feeding area and a non-feeding area by the setting of a blocking member. The fluid disturbance is limited in the feeding area, and the non-feeding area is not affected by the fluid disturbance for sedimentation and salt separation, thereby significantly improving the separation efficiency. In the method, the distillation efficiency of one-time distillation and the optimal glycerol yield are ensured by controlling the proportion of reflux glycerol, the yield of high-whiteness recovered salt is significantly increased, the yield of poor-quality salt and residue is significantly reduced, and the yield of refined glycerol is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of glycerol distillation technology, and in particular to a glycerol distillation and salt separation apparatus and its application method. Background Technology

[0002] The raw material used for glycerol distillation is crude glycerol, whose main component is glycerol, with a content of 80% or more. The remaining components are impurities such as salt, water, fats, aldehydes, soaps, and pigments, among which the salt content is more than 3%. Therefore, crude glycerol needs to be refined and purified to obtain refined glycerol. The traditional industrial method for refining crude glycerol is glycerol distillation, but this process has the following problems: As glycerol is continuously distilled, salt in the crude glycerol will precipitate and settle at the bottom of the first distillation column. The crude glycerol, salt, and impurities at the bottom of the first distillation column are not separated and all enter the second distillation column for re-distillation. Because the residue contains a lot of salt and carries a lot of glycerol, the glycerol yield is significantly reduced. At the same time, the salt particles cause great wear on the conveying equipment and seals, resulting in reduced equipment durability.

[0003] Therefore, to solve the above problems, existing technologies disclose a method for the second distillation of glycerol. This method improves the yield of glycerol by transferring the salt-containing crude glycerol produced after the first distillation to a second distillation tank for second distillation. However, the residue after second distillation still contains a large amount of glycerol, and the residue is difficult to utilize, making the by-product treatment difficult. To further improve the yield of glycerol distillation, existing technologies also disclose a method for desalting by distillation, such as the alternating desalting device for precipitating salts from glycerol by patent number CN205055535U. This device uses a filter device between the first and second distillation columns to filter and separate the salt and impurities in the salt-containing glycerol after the first distillation before transferring it to the second distillation column. However, this type of device has drawbacks in use. Because salt and impurities easily adhere to the filter device, prolonged use can cause the filter device to become clogged, resulting in high cleaning difficulty and low practicality. In addition, the existing technology "Improvement of Glycerol Distillation Desalination Process" sets up a storage tank and a centrifuge between the first and second distillation towers. The salt-containing crude glycerol is pre-stored and then allowed to stand for separation. The salt in the crude glycerol is then separated by centrifugation. However, the above method has low operational continuity and low production efficiency. Furthermore, centrifugation separation has problems such as high separation cost and small separation volume.

[0004] Currently, existing technologies for processing salt-containing glycerol mainly employ a method of first separating the salt and then secondary distillation. The separation devices used mainly include filtration devices, settling separation devices, and centrifugal separation devices. Due to the limited separation capacity of centrifugal devices, filtration devices and settling separation devices are mainly selected in industrial production. In actual use of the settling separation device, this application found that if salt-containing glycerol is directly injected into the salt separation tank, the injected salt-containing glycerol will generate great fluid disturbance. The fluid disturbance will cause the already separated glycerol and salt to remix. At the same time, the disturbance process significantly affects the settling effect and reduces the efficiency of settling separation. Summary of the Invention

[0005] To overcome the problem that the fluid disturbance generated after the injection of salt-containing glycerol into the salt separation tank in the prior art significantly reduces the sedimentation and salt separation efficiency, this application provides a glycerol distillation and salt separation device and its application method. In this device, by setting a sedimentation channel between the salt separation component and the salt storage component, the salt in the salt-containing glycerol can be unaffected by the fluid disturbance during the sedimentation process, which significantly improves the separation speed of the salt-containing crude glycerol and improves the salt separation efficiency.

[0006] The specific technical solution of this invention is as follows:

[0007] A glycerol distillation and salt separation device includes a salt separation component and a salt storage component. The salt separation component includes a tank and a feed component located inside the tank. The bottom of the tank is provided with a settling channel, which communicates with the top of the salt storage component.

[0008] This application provides a glycerol distillation and salt separation device. This device reduces the impact of fluid disturbance on the salt separation of crude glycerol by setting a sedimentation channel between the salt separation component and the salt storage component, thereby significantly improving the salt separation efficiency. This application finds that conventional static salt separation devices are usually integrated devices with salt separation and salt storage components. After injecting crude glycerol containing salt, static stratification is performed to separate the salt and crude glycerol. However, fluid disturbance is generated during the injection of crude glycerol containing salt. At this time, the injected crude glycerol containing salt cannot be sedimented and stratified. The stratification operation can only be performed after the injection of crude glycerol containing salt is stopped, which takes a long time, has low salt separation efficiency, cannot achieve continuous production, and has low production efficiency. Therefore, to address the aforementioned issues, this application separates the salt separation component from the salt storage component via a settling channel. This allows the crude glycerol containing salt to enter the settling channel and then into the salt storage component for settling and separation. This ensures that the crude glycerol is unaffected by fluid disturbances, and salt separation can occur simultaneously with the injection of the crude glycerol. Furthermore, after the crude glycerol in the salt storage component stratifies, the glycerol floats back to the settling tank during the stratification process, while the salt settles in the salt storage component, achieving separation of salt and glycerol. This allows for simultaneous stratification and settling of salt and glycerol during the injection of the crude glycerol, significantly improving separation efficiency and ensuring the continuity of glycerol production.

[0009] Preferably, the tank body is provided with a baffle, one end of which is connected to the top of the tank body and suspended inside the tank body, and the baffle divides the tank body into a feeding area and a non-feeding area.

[0010] Preferably, the ratio of the cross-sectional area of ​​the feeding zone to the non-feeding zone is 1:3 to 4.

[0011] Preferably, the bottom of the baffle does not exceed the plane formed by the upper edge of the bottom of the tank.

[0012] This application finds that fluid disturbances during feeding significantly affect the sedimentation and salt separation process, making it impossible to perform. Typically, a settling separation is required after feeding, but this process is time-consuming, discontinuous, and inefficient. Therefore, this application addresses this problem by installing baffles within the tank. As salt-containing glycerol enters the salt separation device, it gradually accumulates within the separation components. When the surface of the salt-containing glycerol contacts the bottom of the baffle, the baffle separates the accumulated glycerol into a feeding zone and a non-feeding zone. Fluid disturbances are confined to the feeding zone, while the non-feeding zone remains undisturbed. Since the feeding and non-feeding zones are connected, the glycerol enters the non-feeding zone for sedimentation and salt separation. By installing baffles, the impact of fluid disturbances on glycerol sedimentation and salt separation is significantly reduced. Simultaneously, sedimentation and separation occur in the non-feeding zone while the glycerol is fed into the feeding zone, significantly reducing separation time and improving separation efficiency. The bottom of the baffle in this application does not exceed the upper edge of the bottom of the tank. The length of the baffle affects the rate of fluid sedimentation and salt separation. A shorter baffle length will result in a smaller volume of the non-feeding zone, affecting the efficiency of sedimentation and salt separation in the non-feeding zone. If the baffle length is too long, it will result in poor fluid flow, affecting the salt separation efficiency. In addition, the cross-sectional area of ​​the feeding zone and the non-feeding zone in this application also has a significant impact on the efficiency of sedimentation and salt separation. If the ratio of the cross-sectional area of ​​the feeding zone and the non-feeding zone exceeds the range defined in this application, it will result in an excessively large volume of the feeding zone, which will reduce the volume of salt-containing glycerol in the non-feeding zone that is not disturbed by the fluid, thus reducing the salt separation efficiency. If the ratio of the cross-sectional area of ​​the feeding zone and the non-feeding zone is lower than the range defined in this application, it will result in easy blockage in the feeding zone.

[0013] Preferably, the bottom of the tank is funnel-shaped;

[0014] The bottom of the tank in this application is designed as a funnel. Its function is that after the salt settles to the bottom of the tank, it will quickly enter the settling channel along the slope of the funnel under the action of gravity, resulting in a high separation effect.

[0015] Preferably, the length-to-diameter ratio of the tank body is 2 to 3:1.

[0016] A method for applying a glycerol distillation and salt separation device includes the following steps: injecting salt-containing crude glycerol into the feed unit, the salt-containing glycerol entering the tank through the outlet of the feed unit for sedimentation and salt separation treatment to obtain salt and salted glycerol, the salted glycerol being divided into reflux glycerol and second-distilled glycerol, and the salt entering the separation device for separation and purification;

[0017] Preferably, the flow rate of the salt-containing glycerol injected into the feeder is ≥1.4 m / s.

[0018] Preferably, the sedimentation and salt separation treatment includes a first state and a second state;

[0019] The first state includes: the salt storage component is not full, the salt-containing glycerin enters the settling channel from the bottom of the tank and finally enters the salt storage component, the salt-containing glycerin settles and stratifies in the salt storage component, and the salt settles to the bottom of the salt storage component;

[0020] The second state includes: the salt storage component is full, the salt-containing glycerol accumulates in the salt separation component, the salt settles at the bottom of the tank and enters the settling channel and finally settles in the salt storage component, while the separated glycerol accumulates in the tank.

[0021] Preferably, the volume ratio of the refluxed glycerol to the fractionated glycerol is 0.8 to 0.95:1.

[0022] This application also provides a method for applying the aforementioned glycerol separation device. In this method, after the salt-containing glycerol is injected into the glycerol separation device, it undergoes sedimentation and separation. Due to the special structure of the glycerol separation device, the sedimentation and separation process is mainly divided into a first state and a second state. In the first state, the salt storage component is not full. At this time, the salt-containing glycerol enters the separation device and then enters the salt storage component through the sedimentation channel. The salt-containing glycerol in the salt storage component will preferentially collect. When the salt storage component is full, the salt-containing glycerol begins to accumulate in the separation component. Simultaneously, the salt-containing glycerol in the salt storage component is not affected by fluid disturbance and will undergo a rapid sedimentation and separation process within the salt storage component. Salt is deposited in the salt storage component, while the separated glycerol... The glycerol rises to the salt separation component. While the salt storage component is settling and separating the glycerol, the second state is activated. At this time, the glycerol accumulates in the salt separation component. When the surface of the glycerol comes into contact with the bottom of the baffle, the glycerol gradually forms a feed zone and a non-feed zone in the salt separation tank. The feed zone confines the disturbances caused by the glycerol within the feed zone. At the same time, the bottoms of the feed zone and the non-feed zone are connected. The liquid glycerol will fill the feed zone and the non-feed zone evenly. The glycerol in the non-feed zone will not be affected by the fluid disturbance. While feeding, the glycerol settles and separates rapidly. The settled salt enters the settling channel and eventually settles in the salt storage component. The separated glycerol is finally stored in the salt separation component.

[0023] Furthermore, the glycerol separated by the glycerol salting device still contains about 5% dissolved salt that needs further processing. This application further processes the glycerol by separating it into reflux glycerol and double-distilled glycerol. The reflux glycerol is returned to the first distillation column and distilled with the newly added crude glycerol to produce refined glycerol. The double-distilled glycerol is then distilled in the second distillation column to produce yellow glycerol. This method can significantly improve the yield of refined glycerol and remove salt from the glycerol to the maximum extent. Moreover, the salt separated by the glycerol salting device in this application has higher whiteness and fewer impurities than the salt obtained in the second distillation column, and its quality is significantly better.

[0024] Furthermore, this application specifies the ratio of reflux glycerol to desalted glycerol. By limiting this ratio, it is possible to significantly increase the yield of refined glycerol while maximizing the production of high-quality, white salt through the glycerol desalting device, thus reducing the yield of inferior salt and residue. Regarding these effects, firstly, the distillation temperatures and vacuum levels of the first and second distillation columns differ. The first distillation column operates at 160-170°C with a vacuum of <3 mmHg, while the second distillation column operates at 180-190°C with a vacuum of <6 mmHg. The first distillation column produces refined glycerol, while the second distillation column uses the salt-containing glycerol from the first distillation column as raw material for further distillation and separation. Due to the different temperatures and vacuum levels of the first and second distillation columns... High distillation temperatures generate polyglycerol, resulting in yellow glycerol, inferior salts, and residue in the second distillation column. To maximize refined glycerol yield and minimize yellow glycerol production, we typically reflux all the fractionated glycerol back into the first distillation column. However, in practice, this gradually reduces the refined glycerol yield and makes long-term production unstable. Because glycerol remains at high temperatures for extended periods in the distillation column, the proportion of polyglycerol in the distillation system gradually increases. Excessive polyglycerol concentration reduces distillation efficiency, leading to a decrease in refined glycerol yield. Therefore, this application limits the proportion of refluxed glycerol to ensure a higher refined glycerol yield.

[0025] Compared with the prior art, this application has the following technical effects:

[0026] 1. This application reduces the impact of fluid disturbance on the sedimentation and separation of salt-containing crude glycerol by using a salt separation component, a salt storage component, and a sedimentation channel connecting the two, thereby significantly improving the salt separation efficiency;

[0027] 2. This application divides the tank into a feeding zone and a non-feeding zone by setting baffles. The feeding zone confines fluid disturbances within the feeding zone, while the non-feeding zone is unaffected by fluid disturbances and allows for sedimentation and salt separation, thus significantly improving separation efficiency.

[0028] 3. This application also provides a method for applying the glycerol distillation and salt separation apparatus. In this method, the distillation efficiency and optimal glycerol yield of a single distillation are ensured by controlling the proportion of refluxed glycerol. This method can significantly increase the yield of high-whiteness recovered salt, significantly reduce the yield of inferior salt and residue, and significantly improve the yield of refined glycerol. Attached Figure Description

[0029] Figure 1 This is a cross-sectional view of the salt separation device of the present invention.

[0030] The diagram shows a salt separation component 1, a tank 101, a feed component 102, a baffle 103, a salt storage component 2, and a settling channel 3. Detailed Implementation

[0031] The present invention will be further described below with reference to embodiments.

[0032] Example 1:

[0033] like Figure 1 As shown, a glycerol distillation and salt separation device includes a salt separation component 1 and a salt storage component 2. The salt separation component includes a tank body 101 and a feed component 102 located inside the tank body. The bottom of the tank body is provided with a settling channel 3, which is connected to the top of the salt storage component. The length-to-diameter ratio of the tank body is 2.5:1. The tank body is also provided with a vacuum vent, a manhole, an observation mirror hole, a pressure detection hole, a temperature detection hole, and a discharge hole. A baffle 103 is provided inside the tank body. One end of the baffle is connected to the top of the tank body and hangs inside the tank body. The bottom of the baffle does not exceed the plane formed by the upper edge of the bottom of the tank body. The baffle divides the tank body into a feed zone and a non-feed zone. The feed component is located in the feed zone. The cross-sectional area ratio of the feed zone and the non-feed zone is 1:4. The bottom of the tank body is funnel-shaped with a 90° radius on the side wall. The bottom of the tank body is provided with a settling channel 3, which is connected to the salt storage component. The salt storage component is a salt storage tank with a discharge port at the bottom, which is connected to a filter press.

[0034] Example 2:

[0035] A method for using a glycerol distillation and salt separation apparatus, the method comprising the following steps:

[0036] The crude glycerol containing salt is pumped into the feed unit. The glycerol containing salt enters the tank through the outlet of the feed unit for sedimentation and salt separation treatment to obtain salt and salted glycerol. The salted glycerol is divided into reflux glycerol and distilled glycerol. The salt enters the separation device for separation and purification. The flow rate of the glycerol containing salt injected into the feed unit is 3 m / s.

[0037] The sedimentation and salt separation process includes a first state and a second state;

[0038] The first state includes: the salt storage component is not full, the salt-containing glycerin enters the settling channel from the bottom of the tank and finally enters the salt storage component, the salt-containing glycerin settles and stratifies in the salt storage component, and the salt settles to the bottom of the salt storage component;

[0039] The second state includes: the salt storage component is full, the salt-containing glycerol accumulates in the salt separation component, the salt settles at the bottom of the tank and enters the settling channel and finally settles in the salt storage component, while the salt separation glycerol accumulates in the tank.

[0040] The volume ratio of refluxed glycerol to fractionated glycerol is 0.95:1.

[0041] Example 3:

[0042] A method for using a glycerol distillation and salt separation apparatus, the method comprising the following steps:

[0043] The crude glycerol containing salt is pumped into the feed unit. The glycerol containing salt enters the tank through the outlet of the feed unit for sedimentation and salt separation treatment to obtain salt and salted glycerol. The salted glycerol is divided into reflux glycerol and distilled glycerol. The salt enters the separation device for separation and purification. The flow rate of the glycerol containing salt injected into the feed unit is 2.14 m / s.

[0044] The sedimentation and salt separation process includes a first state and a second state;

[0045] The first state includes: the salt storage component is not full, the salt-containing glycerin enters the settling channel from the bottom of the tank and finally enters the salt storage component, the salt-containing glycerin settles and stratifies in the salt storage component, and the salt settles to the bottom of the salt storage component;

[0046] The second state includes: the salt storage component is full, the salt-containing glycerol accumulates in the salt separation component, the salt settles at the bottom of the tank and enters the settling channel and finally settles in the salt storage component, while the salt separation glycerol accumulates in the tank.

[0047] The volume ratio of refluxed glycerol to fractionated glycerol is 0.85:1.

[0048] Example 4:

[0049] A method for using a glycerol distillation and salt separation apparatus, the method comprising the following steps:

[0050] The crude glycerol containing salt is pumped into the feed unit. The glycerol containing salt enters the tank through the outlet of the feed unit for sedimentation and salt separation treatment to obtain salt and salted glycerol. The salted glycerol is divided into reflux glycerol and distilled glycerol. The salt enters the separation device for separation and purification. The flow rate of the glycerol containing salt injected into the feed unit is 1.41 m / s.

[0051] The sedimentation and salt separation process includes a first state and a second state;

[0052] The first state includes: the salt storage component is not full, the salt-containing glycerin enters the settling channel from the bottom of the tank and finally enters the salt storage component, the salt-containing glycerin settles and stratifies in the salt storage component, and the salt settles to the bottom of the salt storage component;

[0053] The second state includes: the salt storage component is full, the salt-containing glycerol accumulates in the salt separation component, the salt settles at the bottom of the tank and enters the settling channel and finally settles in the salt storage component, while the salt separation glycerol accumulates in the tank.

[0054] The volume ratio of refluxed glycerol to fractionated glycerol is 0.8:1.

[0055] Comparative Example 1: (Integrated settling salt container)

[0056] Compared with Example 2, Comparative Example 1 uses a conventional integrated salt separation tank, while the other conditions are the same as in Example 2.

[0057] Comparative Example 2: (No baffles installed)

[0058] Compared with Example 2, Comparative Example 2 differs in that no baffle is installed inside the tank of the salt separation component, while the other conditions are the same as in Example 2.

[0059] Comparative Example 3: (Injection feed rate is too low)

[0060] Compared with Example 2, Comparative Example 3 differs in that the flow rate of the salt glycerol injected into the feeder is 1.13 m / s, while the other conditions are the same as in Example 2.

[0061] Comparative Example 4: (The ratio of refluxed glycerol to decomposed glycerol is 1:1)

[0062] Compared with Example 2, Comparative Example 4 differs in that all fractional-salt glycerol is refluxed as reflux glycerol, while the other conditions are the same as in Example 2.

[0063] Comparative Example 5: (The proportion of refluxed glycerin was too small)

[0064] Compared with Example 2, Comparative Example 5 differs in that the ratio of refluxed glycerol to deionized glycerol is 0.7:1, while the other conditions are the same as in Example 2.

[0065] Comparative Example 6: (No salt separation device installed)

[0066] Compared with Example 2, Comparative Example 6 is different in that no salt separation device is set up, i.e. no sedimentation and salt separation treatment is performed, while the other conditions are the same as those in Example 2.

[0067] Comparative Example 7: (The ratio of the cross-sectional area of ​​the feeding zone to that of the non-feeding zone is too large)

[0068] Compared with Example 2, Comparative Example 7 differs in that the ratio of the cross-sectional area of ​​the feeding zone to the non-feeding zone is 1:1, while the other conditions are the same as in Example 2.

[0069] Comparative Example 8: (The ratio of the cross-sectional area of ​​the feeding zone to that of the non-feeding zone is too small)

[0070] Compared with Example 2, Comparative Example 8 differs in that the ratio of the cross-sectional area of ​​the feeding zone to the non-feeding zone is 1:6, while the other conditions are the same as in Example 2.

[0071] Detection example

[0072] The salt separation efficiency of the glycerol distillation and salt separation devices in Examples 2-4 and Comparative Examples 1-3 and 7-8 was tested. The test results are shown in Table 1. The formula for calculating the salt separation efficiency is: (1 - salt content of reflux glycerol / salt content of feed glycerol) × 100%.

[0073] Table 1. Salt separation efficiency of the glycerol distillation and salt separation device

[0074] Time required to desalinate one ton of salt-containing glycerol (h) Salt separation efficiency (%) Example 2 0.76 87.49 Example 3 0.88 86.10 Example 4 1.14 81.93 Comparative Example 1 ＞12 86.10 Comparative Example 2 0.76 16.60 Comparative Example 3 1.43 77.76 Comparative Example 7 0.76 79.15 Comparative Example 8 0.76 76.37

[0075] As shown in Table 1, Examples 2 and 3 used the glycerol distillation and salt separation device provided in this application. The shortest salt separation time required for each ton of salt-containing glycerol in this application is 0.76 hours, while the salt separation time required for each ton of salt-containing glycerol in Comparative Example 1 exceeds 12 hours. Compared with Comparative Example 1, the salt separation time of this application is significantly reduced. The salt separation efficiency of this application can reach up to 87.49%, while Comparative Example 2, without the baffle, has a salt separation efficiency of only 16.60% in the same salt separation time. Therefore, the above comparison shows that the salt separation efficiency of this application can be significantly improved after the baffle is installed. Furthermore, in Comparative Example 3, when the flow rate of the salt-containing glycerin injected into the feeder was too low, the time required for salt separation per ton of salt-containing glycerin in Comparative Example 3 increased significantly, and the salt separation efficiency also decreased significantly. It can be seen from Comparative Example 3 that the flow rate of the salt-containing glycerin injected into the feeder needs to be limited within the range set in this application. If it is too low, the efficiency of salt separation time will be significantly reduced. In Comparative Examples 7 and 8, the effects of setting the cross-sectional area ratio of the feed area to the non-feed area to exceed the limit of (1:3~4) in this application on the sedimentation and salt separation process were observed. In Comparative Example 7, when the cross-sectional area ratio of the feed area to the non-feed area was too large, the time required for salt separation per ton of salt-containing glycerin was significantly reduced, and the salt separation efficiency was significantly reduced. In Comparative Example 8, when the cross-sectional area ratio of the feed area to the non-feed area was too small, it was found that salt blockage was prone to occur in the feed area after long-term use, requiring frequent cleaning before it could be used again. The actual use effect was poor, and the practicality was low.

[0076] The quality of the products obtained in Examples 2-4 and Comparative Examples 1, 4, and 5 was tested and statistically analyzed. The test results are shown in Table 2.

[0077] Table 2. Products and Yields of Glycerol Distillation and Separation Process

[0078]

[0079] As shown in Table 2, Examples 2-4 use the method provided in this application. Comparative Example 1 uses a conventional integrated salt separation device. Compared with Comparative Example 1, the refined glycerol yield of this application can be increased by up to 3%, and the whiteness of the salt obtained from secondary distillation can be increased by up to 1%. In Comparative Example 2, no baffle is set. The glycerol yield and the whiteness of the salt obtained from secondary distillation in Comparative Example 2 are significantly reduced, and the yield of the secondary distillation residue is significantly increased, up to 4%. In Comparative Example 3, when the flow rate of the salt-containing glycerol injected into the feed is too low, the glycerol yield of Comparative Example 3 is significantly reduced, and the secondary distillation residue yield is also significantly reduced. The yield of distillation residue increased significantly, by up to 3%. In Comparative Example 4, after all the desalted glycerol was refluxed to the first distillation column, it was found that this method could not be used for distillation after 5 days and required shutdown and cleaning before it could continue. The production efficiency was extremely low and could not be applied to actual production. In Comparative Example 5, if the proportion of refluxed glycerol was too small, the yield of refined glycerol would decrease. In addition, in Comparative Example 6, no salt separation device was installed and no sedimentation salt separation treatment was performed before entering the second distillation. Its refined glycerol yield was only 83%, and the second distillation residue rate was the highest, reaching 10%.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for separating salts using a glycerol distillation and salt separation apparatus, characterized in that, Includes the following steps: Salt-containing glycerol is injected into the feed unit at a flow rate ≥1.4 m / s. The salt-containing glycerol enters the tank through the outlet of the feed unit for sedimentation and salt separation treatment to obtain salt and salt-separated glycerol. The salt-separated glycerol is divided into reflux glycerol and distilled glycerol. The volume ratio of reflux glycerol to salt-separated glycerol is 0.8~0.95:

1. The reflux glycerol is returned to the first distillation column and distilled with the newly added crude glycerol to produce refined glycerol. The distilled glycerol enters the second distillation column for distillation to produce yellow glycerol. The salt enters the separation unit for separation and purification. The settling and salt separation process includes a first state and a second state. The first state includes: the salt storage component is not full, and the salt-containing glycerol enters the settling channel from the bottom of the tank and finally enters the salt storage component. The salt-containing glycerol settles and stratifies in the salt storage component, and the salt settles to the bottom of the salt storage component. The second state includes: the salt storage component is full, and the salt-containing glycerol accumulates in the salt separation component. The salt settles at the bottom of the tank and enters the settling channel and finally settles in the salt storage component, while the separated glycerol accumulates in the tank. The glycerol distillation and salt separation device includes a salt separation component (1) and a salt storage component (2). The salt separation component includes a tank body (101) and a feed component (102) located inside the tank body. A settling channel (3) is provided at the bottom of the tank body. The settling channel is connected to the top of the salt storage component. A baffle (103) is provided inside the tank body. One end of the baffle is connected to the top of the tank body and hangs inside the tank body. The bottom of the baffle does not exceed the plane formed by the upper edge of the bottom of the tank body. The baffle divides the tank body into a feed area and a non-feed area. The cross-sectional area ratio of the feed area and the non-feed area is 1:3~4.

2. The method as described in claim 1, characterized in that, The flow rate of the salt-containing glycerol injected into the feed unit is 3 m / s.

3. The method as described in claim 1, characterized in that, The volume ratio of refluxed glycerol to fractionated glycerol is 0.95:

1.

4. The method as described in claim 1, characterized in that, The ratio of the cross-sectional area of ​​the feeding zone to that of the non-feeding zone is 1:

4.

5. The method as described in claim 1, characterized in that, The bottom of the tank is funnel-shaped.

6. The method as described in claim 1, characterized in that, The length-to-diameter ratio of the tank body is 2~3:

1.

7. The method of claim 6, characterized in that, The length-to-diameter ratio of the tank is 2.5:1.

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