Low boiling ester and glycerol separation device for biodiesel distillation process

Abstract

The invention discloses a low-boiling ester and glycerin separation device for a biodiesel distillation process, comprising a vertical cooler, a glycerin separator, a glycerin barrel and a connecting pipeline; a low-boiling ester outlet pipe is arranged on the top of the vertical cooler, a low-boiling ester inlet pipe, a cooling water inlet and outlet are arranged on the side, and a glycerin outlet is arranged at the bottom; the low-boiling ester inlet cylinder at the bottom adopts an extended type to extend the separation time for glycerin precipitation and reduce the glycerin content of the upper low-boiling ester; a middle partition and a heating coil are arranged in the middle and upper part of the glycerin separator, and the middle partition makes the material flow in the separator in a U shape, which is conducive to the separation of glycerin and low-boiling ester; a low-boiling ester outlet pipe is arranged on the upper part of the glycerin separator on one side of the middle partition, and a glycerin inlet pipe is arranged on the top of the separator on the other side; a glycerin outlet pipe is arranged at the bottom of the glycerin separator. The invention has the characteristics of low investment, convenient operation, stable product quality, energy saving, and good effect of separating low-boiling ester and glycerin from each other.

Description

Technical Field

[0001] The invention relates to a biodiesel production device, in particular to a low-boiling ester and glycerol separation device in a biodiesel distillation process. Background Art

[0002] Biodiesel production generally uses waste oil as raw material. Since free fatty acids coexist with oil and contain many impurities in waste oil, it is necessary to purify and remove impurities, and then produce crude fatty acid methyl ester through two-step chemical methods of esterification and transesterification. The crude methyl ester enters the falling film flash evaporation to remove water and low-boiling substances such as methanol, and then heats the crude methyl ester to 250℃ with heat transfer oil, and then enters the biodiesel distillation tower. Under negative pressure of -0.05MPa, the finished biodiesel is obtained from the top of the distillation tower. Since crude methyl ester contains C 16 (carbon 16) and glycerol, when these low-boiling esters and glycerol enter the high-temperature vacuum distillation process of the finished product, the quality and yield of biodiesel are greatly affected. Therefore, the biodiesel distillation process needs to separate low-boiling esters and glycerol from the distillation tower first. In the prior art, the low-boiling ester and glycerol separation device of biodiesel generally adopts the structure of a horizontal cooler and a glycerol separation receiving tank. There are problems: the horizontal cooler has a poor effect on the separation of glycerol in the low-boiling ester, so that the low-boiling ester product contains more glycerol and the quality is unqualified, and the separated glycerol contains more low-boiling esters, which is not conducive to the production of crude glycerol. Summary of the invention

[0003] The purpose of the present invention is to provide a low-boiling ester and glycerin separation device for a biodiesel distillation process with low investment, convenient operation, stable product quality, energy saving, and good separation effect of low-boiling ester and glycerin. To achieve the above purpose, the low-boiling ester and glycerin separation device for a biodiesel distillation process of the present invention comprises a distillation tower, a reboiler, a distillation tower circulation pump, a vertical cooler, a glycerin separation receiving tank, a glycerin separation receiving tank pump, a low-boiling ester receiving tank, a glycerin separator, a glycerin barrel, a separator glycerin pump, a neutralization kettle, a neutralization kettle outlet pump and a glycerin receiving tank; the inlet of the distillation tower circulation pump is connected to the bottom of the distillation tower through a pipeline, and the outlet is connected to the top inlet of the reboiler through a pipeline, and the vapor phase inlet of the distillation tower reboiler is connected to the bottom of the reboiler; the top of the vertical cooler is provided with a low-boiling ester outlet, the side is provided with a low-boiling ester inlet, a cooling water inlet and a cooling water outlet, and the lower part is provided with a glycerin outlet, and the low-boiling ester inlet cylinder at the lower part of the vertical cooler adopts an extended type to increase the height so as to reduce the material flow rate and thus prolong the separation time; the low-boiling ester outlet pipeline is connected to the low-boiling ester receiving tank located at a low position, and the glycerin outlet pipe ... The glycerin separator is provided with a middle partition plate in the middle upper part, so that the glycerin flows in a U shape in the separator, which is beneficial to the separation of glycerin and low-boiling esters. The top of the glycerin separator on one side of the middle partition plate is provided with a glycerin inlet pipe, and the upper part of the side of the glycerin separator on the other side is provided with a low-boiling ester outlet pipe; the lower part of the glycerin separator is provided with a glycerin outlet; the glycerin separator is provided with a steam heating coil; the inlet pipeline of the glycerin separation receiving tank pump is connected to the outlet of the glycerin receiving tank, and the outlet of the glycerin separation receiving tank pump is connected to the glycerin inlet pipe; the low-boiling ester outlet pipe is connected to the low-boiling ester receiving tank located at a low position; the glycerin outlet pipe is connected to the glycerin barrel, the inlet pipe of the separator glycerin pump is connected to the outlet of the glycerin barrel, and the outlet pipe of the separator glycerin pump is connected to the neutralization kettle; the inlet of the neutralization kettle outlet pump is connected to the bottom of the neutralization kettle through a pipeline, and the outlet is connected to the glycerin receiving tank through a pipeline.

[0004] The glycerin inlet pipe at the top of the glycerin separator extends into the separator by 1 meter, so that the glycerin from the glycerin separation tank enters the middle mixing zone of the glycerin separator.

[0005] The low boiling ester outlet at the upper side of the glycerin separator is 0.3 meters away from the top.

[0006] The above-mentioned low-boiling ester and glycerin separation device of the biodiesel distillation process adopts a vertical cooler and an extended low-boiling ester inlet cylinder to increase the height so as to reduce the material flow rate and thus prolong the separation time. The low-boiling ester has a low inlet and a high outlet, so that its liquid level is significantly higher than that of the horizontal cooler in the prior art. Since the density of glycerin is 1.2 tons / m 3 The density of low-boiling ester is 0.87 tons / m 3The difference between the two is obvious, which greatly prolongs the separation time. Glycerol will naturally settle at the bottom due to its heavy density and flow to the glycerol receiving tank, greatly reducing the glycerol content in the low-boiling ester, while the low-boiling ester will float to the top from the bottom due to its light density and flow to the low-boiling ester receiving tank; on the other hand, the low-boiling ester in glycerol is further separated by adding a glycerol separator, and a middle partition is set in the middle and upper part of the glycerol separator, so that the glycerol flows in a U shape in the separator, which is conducive to a more thorough separation of glycerol and low-boiling ester.

[0007] The low-boiling ester and glycerol separation device of the biodiesel distillation process of the present invention has the following technical characteristics and beneficial effects:

[0008] 1. Changing the horizontal low-boiling ester cooler to a vertical low-boiling ester cooler and increasing the height of the separation part will help improve the separation efficiency of glycerol from low-boiling esters during continuous production and ensure the stability of production quality.

[0009] 2. Add a glycerin separator and set a middle partition in the middle and upper part of it, which can automatically separate the low-boiling esters mixed in the glycerin and let them flow by gravity. The glycerin at the bottom of the separator is discharged manually and regularly; because the amount of low-boiling esters in crude glycerin is reduced, it is beneficial to the subsequent production of glycerin to achieve the purpose of energy saving and consumption reduction.

[0010] 3. The glycerol separation device in the low-boiling ester distillation tower has the advantages of simple structure, low manufacturing cost, excellent effect and easy operation.

[0011] 4. It can be promoted and applied in similar production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic structural diagram of a low-boiling ester and glycerol separation device in a biodiesel distillation process of the present invention.

[0013] Figure 2 yes Figure 1 Schematic diagram of the enlarged structure of the middle distillation tower.

[0014] Figure 3 yes Figure 1 Enlarged structural diagram of the neutral cooler.

[0015] Figure 4 yes Figure 1 Schematic diagram of the enlarged structure of the glycerol separator.

[0016] Figure numerals: distillation tower 1, reboiler 2, distillation tower circulation pump 3, vertical cooler 4, glycerin separation receiving tank 5, glycerin separation receiving tank pump 6, low-boiling ester receiving tank 7, glycerin separator middle partition 8, glycerin separator 9, glycerin barrel 10, separator glycerin pump 11, neutralization kettle 12, neutralization kettle outlet pump 13, glycerin receiving tank 14, distillation tower crude methyl ester feed inlet a, distillation tower vacuum outlet b, distillation tower low-boiling ester and glycerin outlet c, distillation tower reboiler vapor phase inlet d, distillation tower methyl ester feed outlet e, distillation tower reboiler circulation port f, vertical cooler low-boiling ester inlet g, vertical cooler cooling water outlet h, vertical cooler low-boiling ester outlet i, vertical cooler cooling water inlet j, vertical cooler glycerin outlet k, glycerin outlet l, glycerin separator low-boiling ester outlet m, glycerin inlet pipe n, glycerin separator steam inlet o. DETAILED DESCRIPTION

[0017] The low-boiling ester and glycerin separation device of the biodiesel distillation process of the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0018] Figure 1-Figure 4 As shown, the low-boiling ester and glycerol separation device of the biodiesel distillation process of the present invention comprises a distillation tower 1, a reboiler 2, a distillation tower circulation pump 3, a vertical cooler 4, a glycerol separation receiving tank 5, a glycerol separation receiving tank pump 6, a low-boiling ester receiving tank 7, a glycerol separator 9, a glycerol barrel 10, a separator glycerol pump 11, a neutralization kettle 12, a neutralization kettle outlet pump 13 and a glycerol receiving tank 14; the inlet of the distillation tower circulation pump 3 is connected to the bottom of the distillation tower 1 through a pipeline, and the outlet is connected to the top inlet of the reboiler 2 through a pipeline, and the vapor phase inlet of the distillation tower reboiler is connected to the bottom of the distillation tower 1 through a pipeline. d is connected to the bottom of the reboiler 2; the top of the vertical cooler 4 is provided with a low-boiling ester outlet i, the side is provided with a low-boiling ester inlet g, a cooling water inlet h and a cooling water outlet j, and the lower part is provided with a glycerol outlet k. The low-boiling ester inlet cylinder at the lower part of the vertical cooler 4 is lengthened to increase the height so as to reduce the material flow rate; the low-boiling ester outlet i pipeline is connected to the low-boiling ester receiving tank 7 located at a low position, and the glycerol outlet k pipeline is connected to the glycerol separation receiving tank 5; the low-boiling ester inlet and high-outlet make its liquid level significantly higher than that of the horizontal cooler. Since the density of glycerol is 1.2 tons / m 3 The density of low-boiling ester is 0.87 tons / m 3, the difference between the two is obvious. After the separation time is greatly extended, glycerol will naturally precipitate at the bottom due to its heavy density and flow to the glycerol separation receiving tank 5 by gravity, so that the glycerol content in the low-boiling ester is greatly reduced, while the low-boiling ester will float from the bottom to the top due to its light density and flow to the low-boiling ester receiving tank 7 located at a low position; the glycerol separator 9 is equipped with an intermediate partition 8 in the middle and upper part, so that glycerol flows in a U shape in the glycerol separator 9, which is conducive to the separation of glycerol and low-boiling ester. The top of the glycerol separator 9 on one side of the intermediate partition 8 is provided with a glycerol inlet pipe n, and the glycerol inlet pipe n is to extend 1 meter, so that the glycerol from the glycerol separation receiving tank 5 enters the middle mixing zone of the glycerol separator 9; the upper side of the glycerol separator 9 on the other side is provided with a low-boiling ester outlet m, and the outlet m is 0.3 meters away from the top; the lower part of the glycerol separator 9 is provided with a glycerol outlet l; the glycerol separator 9 is equipped with a steam heating coil, and its function is to control the temperature in the glycerol separator 9 to meet the set temperature by passing steam The degree is convenient for separating glycerin and low-boiling esters. The inlet pipeline of the glycerin separation receiving tank pump 6 is connected to the outlet of the glycerin separation receiving tank 5, the outlet of the glycerin separation receiving tank pump 6 is connected to the glycerin inlet pipe n, and the low-boiling ester outlet m is connected to the low-boiling ester receiving tank 7 located at a low position; the glycerin outlet pipe l is connected to the glycerin barrel 10, the inlet pipeline of the separator glycerin pump 11 is connected to the outlet of the glycerin barrel 10, and the outlet pipeline of the separator glycerin pump 11 is connected to the neutralization kettle 12; the inlet of the neutralization kettle outlet pump 13 is connected to the bottom of the neutralization kettle 12 through a pipeline, and the outlet is connected to the glycerin receiving tank 14 through a pipeline; the low-boiling ester floating on the upper part of the glycerin separator 9 flows to the low-boiling ester receiving tank 7 located at a low position by utilizing the height difference, thereby naturally forming a three-part composition material of upper low-boiling ester, middle glycerin and low-boiling ester mixture, and lower glycerin, and the glycerin at the bottom of the glycerin separator 9 is regularly discharged from the outlet pipe l to the glycerin barrel 10, and the glycerin discharge is stopped when the glycerin and low-boiling ester mixture is discharged.

[0019] The specific operation process during production is as follows: crude biodiesel is firstly removed from most of the low-boiling substances (such as methanol and water) in a flash evaporator, and then enters the crude methyl ester feed port a of the distillation tower in the middle of the distillation tower 1. The crude methyl ester is heated to a certain temperature by the reboiler 2 of the distillation tower 1 and the remaining low-boiling esters and glycerol are removed under vacuum. The low-boiling esters and glycerol flow from the distillation tower 1 to the lower part of the vertical cooler 4 by gravity. The low-boiling ester flows from bottom to top in the vertical cooler 4 and flows by gravity to the low-boiling ester receiving tank 7. The glycerol is naturally precipitated at the lower part of the vertical cooler 4 and flows by gravity to the glycerol receiving tank 7. The separated glycerin is pumped from the glycerin separation receiving tank 5 by the glycerin separation receiving tank pump 6 to the glycerin separator 9 for further separation of glycerin and low-boiling esters. The glycerin naturally sinks to the bottom of the glycerin separator 9 and is discharged to the glycerin barrel 10 by manual control. The glycerin in the glycerin barrel 10 is then pumped to the neutralization kettle 12 by the separator glycerin pump 11 for neutralization. After neutralization, the glycerin is pumped from the bottom of the neutralization kettle by the neutralization kettle outlet pump 13 to the glycerin receiving tank 14. The low-boiling ester separated from the glycerin separator 9 floats on the upper part of the glycerin separator 9 and flows to the low-boiling ester receiving tank 7 by gravity.

Claims

1. A device for separating low-boiling esters and glycerol in a biodiesel distillation process, comprising a distillation tower (1), a reboiler (2), a distillation tower circulation pump (3), a glycerol separation receiving tank (5), a glycerol separation receiving tank pump (6), a low-boiling ester receiving tank (7), a separator glycerol pump (11), a neutralization kettle (12), a neutralization kettle outlet pump (13) and a glycerol receiving tank (14); the inlet of the distillation tower circulation pump (3) is connected to the bottom of the distillation tower (1) through a pipeline, the outlet is connected to the top inlet of the reboiler (2) through a pipeline, and the vapor phase inlet (d) of the distillation tower reboiler is connected to the bottom of the reboiler (2); the inlet of the neutralization kettle outlet pump (13) is connected to the bottom of the neutralization kettle (12) through a pipeline, and the outlet is connected to the glycerol receiving tank (14) through a pipeline; the device is characterized in that: It also includes a vertical cooler (4), a glycerin separator (9) and a glycerin barrel (10); the top of the vertical cooler (4) is provided with a vertical cooler low-boiling ester outlet (i), the side is provided with a vertical cooler low-boiling ester inlet (g), a vertical cooler cooling water inlet (h) and a vertical cooler cooling water outlet (j), and the bottom is provided with a vertical cooler glycerin outlet (k); the low-boiling ester inlet cylinder at the bottom of the vertical cooler (4) is of an extended type to increase the height so as to reduce the material flow rate and thus prolong the separation time; the vertical cooler low-boiling ester outlet (i) is connected to a low-boiling ester receiving tank (7) arranged at a low position through a pipeline, and the vertical cooler glycerin outlet (k) is connected to a glycerin separation receiving tank (5) through a pipeline; the glycerin separator (9) is provided with a middle partition plate (8) in the middle and upper part so that the glycerin flows in the glycerin separator (9) in a U shape, which is beneficial to the separation of glycerin and low-boiling ester. The glycerin separator (9) is provided with a glycerin inlet pipe (n) at the top of one side of the middle partition (8), and a glycerin separator low-boiling ester outlet (m) is provided at the upper side of the glycerin separator (9) on the other side; a glycerin outlet (l) of the glycerin separator is provided at the lower part of the glycerin separator (9); a steam heating coil is installed in the glycerin separator (9); the inlet pipe of the glycerin separation receiving tank pump (6) is connected to the outlet of the glycerin separation receiving tank (5), the outlet of the glycerin separation receiving tank pump (6) is connected to the glycerin inlet pipe (n), and the glycerin separator low-boiling ester outlet (m) pipe is connected to the low-boiling ester receiving tank (7) arranged at a low position; the glycerin outlet (l) pipe is connected to the glycerin barrel (10), the inlet pipe of the separator glycerin pump (11) is connected to the outlet of the glycerin barrel (10), and the outlet pipe of the separator glycerin pump (11) is connected to the neutralization kettle (12).

2. The low-boiling ester and glycerol separation device of biodiesel distillation process as claimed in claim 1, characterized in that: The glycerin inlet pipe (n) at the top of the glycerin separator (9) extends 1 meter into the glycerin separator (9) so that the glycerin from the glycerin separation receiving tank (5) enters the mixing zone in the middle of the glycerin separator (9).

3. The low-boiling ester and glycerol separation device of biodiesel distillation process as claimed in claim 1, characterized in that: The glycerin separator low-boiling ester outlet (m) at the upper side of the glycerin separator (9) is 0.3 m away from the top.

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