Crude glycerine refining and impurity removing equipment

Abstract

The invention discloses crude glycerine refining and impurity removing equipment which comprises a reaction unit, a low-boiling-point removing unit and a distillation unit, the reaction unit comprises an alcohol-containing crude glycerine tank, an esterification oil tank and a reaction tower, and the alcohol-containing crude glycerine tank and the esterification oil tank are both communicated with a feeding port of the reaction tower; the low-boiling-point removal unit comprises a first evaporation device, and a feed port of the first evaporation device is communicated with a heavy-phase discharge port of the reaction tower; the distillation unit comprises a first distillation device and a glycerin tank, a feed port of the first distillation device is communicated with a liquid phase outlet of the first evaporation device, and a condensation outlet of the first distillation device is communicated with the glycerin tank. Compared with the prior art, the crude glycerine refining and impurity removing equipment provided by the invention has the advantages that glyceryl esterified oil obtained by deacidifying waste oil and fat and alcohol-containing crude glycerine are mixed, and alcohol and alkali in the alcohol-containing crude glycerine are used as raw materials for transesterification, so that the content of alkali and alcohol in alcohol-containing glycerine soap is reduced, the concentration of glycerine is increased, and the purity of the alcohol-containing glycerine soap is improved; and performing low-boiling-point removal, distillation, settling separation and the like to obtain refined glycerol.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biodiesel, and particularly relates to a crude glycerol refining and impurity removing equipment. BACKGROUND

[0002] Biodiesel is a kind of bio-liquid fuel considered to be environmentally friendly, which is prepared from waste oil (kitchen waste oil, slightly water oil, acidified oil, etc.). This bio-fuel can be used like diesel. The most common method for preparing biodiesel is transesterification. Waste oil reacts with alcohol (usually methanol) in the presence of a catalyst to produce fatty acid esters. Crude glycerol is the main by-product of the production process, which has complex components and generally includes: glycerol, methanol, fatty acid methyl ester, polyglycerol, fatty acid potassium soap, monoglyceride, potassium hydroxide, etc.

[0003] In the production process of preparing distillation-free biodiesel from waste oil, a by-product of alcohol-containing crude glycerol will be obtained, that is, glycerol containing a certain amount of methanol, alkali and other impurities. In order to purify the alcohol-containing crude glycerol and obtain refined glycerol with high purity, the traditional process usually uses hydrochloric acid solution for acidification treatment to reduce the fatty acid potassium soap (RCOOK) in the raw material into free fatty acid (RCOOH) and generate potassium chloride (KCl); potassium hydroxide (KOH) is neutralized to further generate salts, and after separating the acidified oil, sodium hydroxide (NaOH) is used to neutralize the acid crude glycerol solution, so that the crude glycerol solution is alkaline for subsequent rectification and purification. However, in this process, a large amount of water is consumed in the multi-step acid-base neutralization reaction, and a large amount of salt is generated, resulting in high energy consumption in the subsequent dehydration process and a large amount of solid waste salt.

[0004] Therefore, it is urgent to propose a new purification and impurity removal equipment to solve the above problems. SUMMARY

[0005] The present application aims to overcome the above technical deficiencies and provide a crude glycerol refining and impurity removing equipment to solve the technical problem of high energy consumption in the subsequent dehydration process and a large amount of solid waste salt in the existing technology.

[0006] To achieve the above technical purpose, the present application adopts the following technical scheme: The present application provides a crude glycerol refining and impurity removing equipment, which comprises a reaction unit, a low-boiling removal unit and a distillation unit, The reaction unit comprises an alcohol-containing crude glycerol tank, an esterified oil tank and a reaction tower, the reaction tower has a heavy phase discharge port, a feed port and a light phase discharge port arranged in sequence from bottom to top, and the alcohol-containing crude glycerol tank and the esterified oil tank are both connected to the feed port of the reaction tower; The low-boiling unit comprises a first evaporation device having a feed inlet, a liquid phase outlet and a gas phase outlet, the feed inlet of the first evaporation device being communicated with the heavy phase outlet of the reaction column; The distillation unit comprises a first distillation device having a feed inlet, a condensate outlet and a concentrate outlet, the feed inlet of the first distillation device being communicated with the liquid phase outlet of the first evaporation device, and the condensate outlet of the first distillation device being communicated with the glycerol tank.

[0007] In some embodiments, the reaction unit further comprises a methanol tank, the methanol tank also being communicated with the feed inlet of the reaction column.

[0008] In some embodiments, the reaction column comprises a column body having the heavy phase outlet, the feed inlet and the light phase outlet, and a first circulation device comprising a first distributor, the column body having a grid plate below the first distributor, the grid plate and the first distributor being arranged in the column body to divide the column body into a heavy phase settling separation zone, a loop reaction zone and a light phase settling separation zone arranged in sequence from bottom to top, the heavy phase outlet being communicated with the heavy phase settling separation zone, the feed inlet being communicated with the loop reaction zone, and the light phase outlet being communicated with the light phase settling separation zone.

[0009] In some embodiments, the first circulation device further comprises a first circulation pipe and a first circulation pump, the first circulation pipe having an upper end below the light phase outlet and being communicated with the light phase settling separation zone, and a lower end connected to the first distributor, the first circulation pump being arranged on the first circulation pipe to drive the material to flow from the upper end of the first circulation pipe to the first distributor, and the first distributor being arranged downwardly.

[0010] In some embodiments, the reaction column further comprises a second circulation device, the second circulation device comprising a second circulation pipe, a second circulation pump and a second distributor, the second circulation pipe having a lower end communicated with the heavy phase settling separation zone, and an upper end extending from the feed inlet into the loop reaction zone and connected to the second distributor, the second distributor being arranged in the loop reaction zone and having a discharge end arranged upwardly, and the second circulation pump being arranged on the second circulation pipe to drive the material to flow from the lower end of the second circulation pipe to the second distributor.

[0011] In some embodiments, the reaction unit further comprises a secondary crude glycerol-containing temporary tank, the heavy phase outlet of the reaction column being communicated with the feed inlet of the first evaporation device via the secondary crude glycerol-containing temporary tank.

[0012] In some embodiments, the low-boiling removal unit further comprises a crude methanol tank and a first heat exchanger, the gas phase outlet of the first evaporation device is communicated with the crude methanol tank, and the first heat exchanger is arranged on a pipeline between the first evaporation device and the crude methanol tank to condense methanol vapor.

[0013] In some embodiments, the low-boiling removal unit further comprises a crude glycerol buffer tank, the liquid phase outlet of the first evaporation device is communicated with the feed inlet of the first distillation device via the crude glycerol buffer tank.

[0014] In some embodiments, the distillation unit further comprises a second distillation device, the second distillation device also has a feed inlet, a condensate outlet and a concentrate outlet, the concentrate outlet of the first distillation device is communicated with the feed inlet of the second distillation device, and the condensate outlet of the second distillation device is communicated with the glycerol tank.

[0015] In some embodiments, a tail gas treatment unit is further included, the tail gas treatment unit comprises a main pipeline, a plurality of branch pipelines and a second heat exchange device, the main pipeline is connected with the alcohol-containing crude glycerol tank and the reaction tower via each of the branch pipelines, and the second heat exchange device is arranged on the main pipeline.

[0016] Compared with the prior art, the crude glycerol refining and impurity removing equipment provided by the present application can not only reduce the alkali and alcohol content in the alcohol-containing glycerol soap and increase the glycerol concentration, but also can recover part of the fatty acid methyl ester dispersed in the alcohol-containing crude glycerol and reduce the loss of the fatty acid methyl ester, by mixing and processing the glycerol esterified oil obtained by deacidifying waste oil and the byproduct alcohol-containing crude glycerol, using the alcohol and alkali in the alcohol-containing crude glycerol as raw materials for the ester exchange reaction. Then, by further performing steps such as low-boiling removal, distillation and sedimentation separation, refined glycerol meeting the standard requirements can be obtained. When refining glycerol, the present application avoids the use of additional acid and alkali solutions, does not need to consume a large amount of water, and will not produce a large amount of solid waste salt, and has the advantages of being green and environmentally friendly and producing less solid waste. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of the crude glycerol refining and impurity removing equipment provided by the present application; Figure 2 is a structural schematic diagram of the reaction tower in Figure 1 Figure 3 is a partial structural schematic diagram of the low-boiling removal unit in Figure 1 Figure 4 is a structural schematic diagram of the first distillation device in Figure 1 is a structural schematic diagram of the first distillation device in

[0018] ​​​In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0019] In the production process of preparing distillation-free biodiesel by using waste oil, a by-product of alcohol-containing crude glycerol is obtained. The traditional method of removing impurities from crude glycerol consumes a large amount of water and produces a large amount of salt. The present application provides a crude glycerol refining and impurity removal equipment which can refine glycerol while producing only a small amount of solid waste, having the advantages of green and environmental protection.

[0020] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of the crude glycerol refining and impurity removal equipment provided by the embodiments of the present application. Figure 1 The arrow in the figure indicates the flow direction of liquid or gas. The crude glycerol refining and impurity removal equipment comprises a reaction unit, a low-boiling removal unit and a distillation unit.

[0021] The reaction unit comprises an alcohol-containing crude glycerol tank 11, an esterified oil tank 12 and a reaction column 13. The alcohol-containing crude glycerol tank 11 stores the by-product of alcohol-containing crude glycerol produced during the production of distillation-free biodiesel, i.e. glycerol containing a certain amount of methanol, alkali and other impurities. The esterified oil tank 12 stores a part of the glycerol esterified oil obtained by deacidifying waste oil. The waste oil is reacted with glycerol to reduce the acid value, and the glycerol esterified oil is obtained, a part of which is stored in the esterified oil tank 12.

[0022] Please refer to Figure 2 , Figure 2 is a structural schematic diagram of the reaction column 13 in Figure 1 . The reaction column 13 has a heavy phase discharge port 1301, a feed port 1302 and a light phase discharge port 1303 arranged in order from bottom to top. The alcohol-containing crude glycerol tank 11 and the esterified oil tank 12 are both connected to the feed port 1302 of the reaction column 13. The alcohol-containing crude glycerol and the glycerol esterified oil are reacted in the reaction column 13, the alcohol and alkali in the crude glycerol are consumed by the reaction, and the glycerol content is increased. Moreover, the crude glycerol has a large density and will be discharged from the heavy phase discharge port 1301. The oil obtained by the reaction has a small density and will overflow from the light phase discharge port 1303 and be guided to other recovery equipment.

[0023] Please refer to Figure 3 , Figure 3 is a partial structural schematic diagram of the low-boiling removal unit in Figure 1 . The low-boiling removal unit comprises a first evaporation device 21, which has a feed port 211, a liquid phase outlet 212 and a gas phase outlet 213. The feed port 211 of the first evaporation device 21 is connected to the heavy phase discharge port 1301 of the reaction column 13. The crude glycerol after the reaction is evaporated in the first evaporation device 21 to remove low-boiling substances.

[0024] Please refer to Figure 4 , the distillation unit includes a first distillation device 31 and a glycerol tank 32, the first distillation device 31 has a feed port 311, a condensation outlet 312 and a concentration outlet 313. The feed port 311 of the first distillation device 31 is communicated with the liquid phase outlet 212 of the first evaporation device 21, and the condensation outlet 312 of the first distillation device 31 is communicated with the glycerol tank 32. The first distillation device 31 can condense glycerol, further improve the purity of glycerol, and the condensed glycerol is transported into the glycerol tank 32, and after standing and settling, the required refined glycerol can be obtained.

[0025] The crude glycerol refining and impurity removing equipment provided by the application can mix and process glycerol esterification oil and by-product alcohol-containing crude glycerol obtained by deacidifying waste oil, use alcohol and alkali in the alcohol-containing crude glycerol as raw materials for ester exchange reaction, reduce the alkali and alcohol content in the alcohol-containing glycerol soap, improve the glycerol concentration, recover part of the fatty acid methyl ester dispersed in the alcohol-containing crude glycerol, and reduce the loss amount of the carried fatty acid methyl ester; then, through the steps of low-boiling removal, distillation and sedimentation separation, refined glycerol meeting the standard requirements can be obtained. The use of additional acid and alkali solutions is avoided, a large amount of water does not need to be consumed, and a large amount of solid waste salt will not be produced, so that the advantages of green environmental protection and less solid waste are achieved.

[0026] Please refer to Figure 2 In some embodiments, the reaction column 13 includes a column body 131, a grid plate 132 and a first circulating device 133, the column body 131 has a heavy phase outlet 1301, a feed port 1302 and a light phase outlet 1303. The first circulating device 133 includes a first distributor 1331, the grid plate 132 is located below the first distributor 1331, and the grid plate 132 and the first distributor 1331 are both arranged in the column body 131, and a heavy phase sedimentation separation zone 1304, a loop reaction zone 1305 and a light phase sedimentation separation zone 1306 are sequentially arranged from bottom to top in the column body 131. The heavy phase outlet 1301 is communicated with the heavy phase sedimentation separation zone 1304, the feed port 1302 is communicated with the loop reaction zone 1305, and the light phase outlet 1303 is communicated with the light phase sedimentation separation zone 1306. The grid plate 132 is a porous structure, and the material can pass through the grid plate 132, but the grid plate 132 can slow down the speed of the material passing through.

[0027] Further, the first circulation device 133 further comprises a first circulation pipe 1332 and a first circulation pump 1333. The upper end of the first circulation pipe 1332 is located below the light phase outlet 1303 and communicates with the light phase settling separation zone 1306, the lower end of the first circulation pipe 1332 is connected to the first distributor 1331, and the first circulation pump 1333 is arranged on the first circulation pipe 1332 to drive the material to flow from the upper end of the first circulation pipe 1332 to the first distributor 1331. The first distributor 1331 is arranged downwardly to send the material into the loop reaction zone 1305.

[0028] In the preferred embodiment, the reaction tower 13 further comprises a second circulation device 134, which comprises a second distributor 1341, a second circulation pipe 1342 and a second circulation pump 1343. The lower end of the second circulation pipe 1342 communicates with the heavy phase settling separation zone 1304, and the upper end of the second circulation pipe 1342 extends from the feed inlet 1302 into the loop reaction zone 1305 and is connected to the second distributor 1341. The second distributor 1341 is arranged in the loop reaction zone 1305 and the material outlet end of the second distributor 1341 is arranged upwardly. The second circulation pump 1343 is arranged on the second circulation pipe 1342 to drive the material to flow from the lower end of the second circulation pipe 1342 to the second distributor 1341, and the second distributor 1341 sends the material into the loop reaction zone 1305.

[0029] The material enters the loop reaction zone 1305 through the feed inlet 1302, and in some embodiments, the material can also be fed through the second circulation device 134, i.e. the feed pipe communicates with the second circulation pipe 1342 or the second circulation pump 1343. The material in the loop reaction zone 1305 performs the ester exchange reaction, the light phase product moves upwardly, enters the light phase settling separation zone 1306 for settling separation, and the light phase product continues to move upwardly, part of which is transported by the first circulation device 133 into the loop reaction zone 1305 for reaction again, and the other part is overflowed and discharged through the light phase outlet 1303. The heavy phase product produced by the ester exchange reaction in the loop reaction zone 1305 moves downwardly through the grid plate 132 and falls into the heavy phase settling separation zone 1304, and after settling separation in the heavy phase settling separation zone 1304, the heavy phase product is discharged through the heavy phase outlet 1301. The light material in the upper layer of the heavy phase settling separation zone 1304 can also be transported back into the loop reaction zone 1305 through the second circulation device 134.

[0030] In some embodiments, the reaction column 13 further comprises a heating device 135, which comprises a heater 1351, a temperature sensor 1352 and a controller 1353. The heater 1351 is arranged in the loop reaction zone 1305 and located between the upper end of the second circulation pipe 1342 and the second distributor 1341. The temperature sensor 1352 is arranged in the light phase sedimentation separation zone 1306 and connected with the heater 1351 through the controller 1353. The heater 1351 can be in the form of electric heating, steam heating, etc. to maintain the reaction temperature in the loop reaction zone 1305. The temperature sensor 1352 indirectly infers the temperature of the loop reaction zone 1305 by detecting the temperature of the light phase sedimentation separation zone 1306, so as to feedback adjust the heating power of the heater 1351 through the controller 1353, so as to keep the reaction temperature in a suitable range.

[0031] In some embodiments, the reaction unit further comprises a methanol tank 14, which is also connected with the feed inlet 1301 of the reaction column 13. The methanol tank 14 stores methanol. Since the waste oil is widely available and its internal composition and content are unstable, when the transesterification reaction of the crude glycerol and glyceride oil in the reaction column 13 occurs and the methanol is insufficient, the methanol tank 14 can supplement the appropriate amount of methanol into the reaction column 13. The addition of methanol can also play a role in demulsification, promoting the separation of oil and alcohol-containing glycerol soap.

[0032] In some embodiments, the reaction unit further comprises a secondary crude glycerol containing tank 15, and the heavy phase outlet 1301 of the reaction column 13 is connected with the feed inlet 211 of the first evaporation device 21 through the secondary crude glycerol containing tank 15. The alcohol-containing crude glycerol discharged from the heavy phase outlet 1301 of the reaction column 13 is first stored in the secondary crude glycerol containing tank 15, and then transported to the first evaporation device 21 for evaporation to remove low-boiling substances. The alcohol-containing crude glycerol stored in the secondary crude glycerol containing tank 15 also contains alcohol, but since it has undergone the transesterification reaction in the reaction column 13, the content of methanol and alkali in the alcohol-containing crude glycerol in the secondary crude glycerol containing tank 15 is lower than that of the initial alcohol-containing crude glycerol in the alcohol-containing crude glycerol tank 11. In other words, the alcohol-containing crude glycerol in the secondary crude glycerol containing tank 15 has a higher glycerol content.

[0033] Please refer again to Figure 1 and Figure 3 In some embodiments, the first evaporation device 21 adopts a wiped film evaporator. The low-boiling unit further comprises a crude methanol tank 22 and a first heat exchanger 23, and the gas phase outlet 213 of the first evaporation device 21 is connected with the crude methanol tank 22, and the first heat exchanger 23 is arranged on the pipeline between the first evaporation device 21 and the crude methanol tank 22. The first evaporation device 21 can control the heating temperature to make the low-boiling substances in the alcohol-containing crude glycerol, such as methanol, evaporate first. The first heat exchanger 23 condenses and recycles these low-boiling substances.

[0034] In the present embodiment, a water ring vacuum pump 24 is arranged between the first evaporation device 21 and the crude methanol tank 22, and the crude methanol tank 22 is also connected with the water ring vacuum pump 24, and a liquid ring of the water ring vacuum pump 24 is formed by the crude methanol in the crude methanol tank 22. A liquid level monitoring device is arranged on the crude methanol tank 22, and when the internal methanol content reaches an upper limit value, a part of the crude methanol is extracted through a pipeline and an extraction device.

[0035] In the preferred embodiment, two evaporation devices can also be arranged in series, and the temperatures of the two evaporation devices are different, and they are respectively used for evaporating methanol and other low-boiling-point substances, so that the content of the crude methanol condensed in the crude methanol tank 22 is higher, and the workload of subsequent purification treatment is reduced.

[0036] In some embodiments, the low-boiling removal unit also comprises a crude glycerol buffer tank 25, and the liquid phase outlet 212 of the first evaporation device 21 is connected to the feed inlet 311 of the first distillation device 31 through the crude glycerol buffer tank 25.

[0037] Please refer to Figure 1 and Figure 4 In some embodiments, the first distillation device 31 adopts a molecular still, which can distill the material, and the distilled product is discharged from the condensation outlet 312, and the remaining product is discharged from the concentration outlet 313.

[0038] In some embodiments, the distillation unit also comprises a second distillation device 33, which is similar to the first distillation device 31 and also has a feed inlet, a condensation outlet and a concentration outlet, and the second distillation device 33 can also adopt a molecular still. The concentration outlet 313 of the first distillation device 31 is connected to the feed inlet of the second distillation device 33, and the condensation outlet of the second distillation device 33 is connected to the glycerol tank 32. The concentrated product after the distillation of the first distillation device 31 is transported into the second distillation device 33 for concentration again, so as to fully recover the crude glycerol therein and store it in the glycerol tank 32 for sedimentation and separation, so as to obtain refined glycerol with the required purity. The concentrated outlet of the second distillation device 33 discharges glycerol pitch.

[0039] In some embodiments, due to the volatility of various materials, the crude glycerol refining and impurity removal equipment also comprises a tail gas treatment unit 4, which comprises a main pipe 41, a plurality of branch pipes 42 and a second heat exchange device 43. The main pipe 41 is connected with the crude glycerol tank 11 containing alcohol, the reaction tower 13, the methanol tank 14, the secondary crude glycerol containing temporary storage tank 15 and the crude methanol tank 22 through the branch pipes 42 respectively, and the second heat exchange device 43 is arranged on the main pipe 41 and used for condensing various volatile gases into liquids, which are collected and then input back into the equipment for reaction.

[0040] It is easily understood that valves and pumps can be arranged on the various pipes of the apparatus to control the flow of liquid or gas as required.

[0041] The above description of the preferred embodiments of the present application is not intended to limit the scope of the present application. Various other changes and modifications can be made to the present application according to the technical concept of the present application, and such changes and modifications should be included in the scope of the present application.

Claims

1. A crude glycerol impurity removal apparatus, characterized by, The reaction unit comprises a crude glycerol tank containing alcohol, an esterification oil tank and a reaction tower, the reaction tower has a heavy phase discharge port, a feed port and a light phase discharge port arranged in sequence from bottom to top, the crude glycerol tank containing alcohol and the esterification oil tank are both communicated with the feed port of the reaction tower. The low boiling removal unit comprises a first evaporation device, the first evaporation device has a feed port, a liquid phase outlet and a gas phase outlet, the feed port of the first evaporation device is communicated with the heavy phase discharge port of the reaction tower. The distillation unit comprises a first distillation device and a glycerol tank, the first distillation device has a feed port, a condensation outlet and a concentration outlet, the feed port of the first distillation device is communicated with the liquid phase outlet of the first evaporation device, and the condensation outlet of the first distillation device is communicated with the glycerol tank. The reaction unit further comprises a methanol tank, and the methanol tank is also communicated with the feed port of the reaction tower.

2. The crude glycerol impurity removal apparatus of claim 1, wherein, The reaction tower comprises a tower body, a grid plate and a first circulation device, the tower body has the heavy phase discharge port, the feed port and the light phase discharge port, the first circulation device comprises a first distributor, the grid plate is located below the first distributor, and the grid plate and the first distributor are both arranged in the tower body to divide the tower body into a heavy phase sedimentation separation zone, a loop reaction zone and a light phase sedimentation separation zone arranged in sequence from bottom to top, the heavy phase discharge port is communicated with the heavy phase sedimentation separation zone, the feed port is communicated with the loop reaction zone, and the light phase discharge port is communicated with the light phase sedimentation separation zone.

3. The crude glycerol impurity removal apparatus of claim 1, wherein, The first circulation device further comprises a first circulation pipe and a first circulation pump, the upper end of the first circulation pipe is located below the light phase discharge port and is communicated with the light phase sedimentation separation zone, the lower end of the first circulation pipe is connected with the first distributor, and the first circulation pump is arranged on the first circulation pipe to drive the material to flow from the upper end of the first circulation pipe to the first distributor, and the first distributor is arranged downward.

4. The crude glycerol impurity removal apparatus of claim 3, wherein, The reaction tower further comprises a second circulation device, the second circulation device comprises a second circulation pipe, a second circulation pump and a second distributor, the lower end of the second circulation pipe is communicated with the heavy phase sedimentation separation zone, the upper end of the second circulation pipe extends from the feed port into the loop reaction zone and is connected with the second distributor, the second distributor is arranged in the loop reaction zone and the discharge end of the second distributor is arranged upward, and the second circulation pump is arranged on the second circulation pipe to drive the material to flow from the lower end of the second circulation pipe to the second distributor.

5. The crude glycerol impurity removal apparatus of claim 4, wherein, The reaction unit further comprises a secondary crude glycerol containing temporary storage tank, and the heavy phase discharge port of the reaction tower is communicated with the feed port of the first evaporation device through the secondary crude glycerol containing temporary storage tank.

6. The crude glycerol refining and impurity removal apparatus of claim 1, wherein, The low boiling removal unit further comprises a crude methanol tank and a first heat exchanger, the gas phase outlet of the first evaporation device is communicated with the crude methanol tank, and the first heat exchanger is arranged on the pipeline between the first evaporation device and the crude methanol tank to condense methanol vapor.

7. The crude glycerol refining and impurity removal apparatus of claim 1, wherein, The low boiling removal unit further comprises a crude glycerol buffer tank, and the liquid phase outlet of the first evaporation device is communicated with the feed port of the first distillation device through the crude glycerol buffer tank.

8. The crude glycerol refining and impurity removal apparatus of claim 1, wherein, ​ 9. The crude glycerol refining and impurity removal apparatus of claim 1, wherein, The distillation unit further comprises a second distillation device, which also has a feed inlet, a condensate outlet and a concentrate outlet, the concentrate outlet of the first distillation device is communicated with the feed inlet of the second distillation device, and the condensate outlet of the second distillation device is communicated with the glycerol tank.

10. The crude glycerol refining and impurity removal apparatus of claim 1, wherein, The exhaust gas treatment unit is also provided, which comprises a main pipe, a plurality of branch pipes and a second heat exchange device, the main pipe is connected with the crude glycerol tank containing alcohol and the reaction tower via each branch pipe respectively, and the second heat exchange device is arranged on the main pipe.

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