LIQUID-LIQUID MIXER, LIQUID-LIQUID REACTION APPARATUS COMPRISING LIQUID-LIQUID MIXER, AND LIQUID-LIQUID REACTION METHOD USING LIQUID-LIQUID MIXER

Abstract

The present disclosure provides a microchannel liquid-liquid mixing device, comprising a microchannel component and a shell, wherein the microchannel component is fixed inside the shell, wherein an inlet is provided at one end of the shell for feeding at least two reaction liquid phases, and an outlet is provided at the other end for discharging a mixed material; said microchannel component comprises multiple stacked sheets and oleophilic fiber filaments and hydrophilic fiber filaments filled in the crevices between adjacent sheets, wherein the fiber filaments form several microchannels between them, and the fiber filaments are clamped and fixed by the sheets. The microchannel liquid-liquid mixing device is used for at least two reaction liquid phases to form a mixed material, and the at least two reaction liquid phases are cut by fiber filaments and mixed in the microchannel mixing device to form a mixed material. The present invention also discloses the liquid-liquid reaction apparatus and liquid-liquid reaction process comprising the above microchannel liquid-liquid mixing device, such as an olefin hydration reaction apparatus and an olefin hydration process, and a reaction apparatus and process for producing biodiesel with transesterification.

Claims

1. A microchannel liquid-liquid mixing device, comprising a microchannel component and a shell, wherein the microchannel component is fixed inside the shell, wherein an inlet is provided at one end of the shell for feeding at least two reaction liquid phases, and an outlet is provided at the other end for discharging a mixed material; said microchannel component comprises multiple stacked sheets and oleophilic and hydrophilic fiber filaments filled in the crevices between adjacent sheets, wherein the fiber filaments form several microchannels between them, and the fiber filaments are clamped and fixed by the sheets.

2. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the microchannel component in the shell of the microchannel mixer are divided into a feeding end and a discharging end along the direction of the crevice, wherein a feeding distribution space is provided between the material inlet and the feeding end, and a discharging distribution space is provided between the material outlet and the discharging end, except for the feeding end and the discharging end, all other ends of the microchannel component are connected to the shell in a sealed manner.

3. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said fiber filaments can be arranged in single or multiple layers, preferably 1-50 layers, and more preferably 1-5 layers.

4. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: when said fiber filaments are arranged in multiple layers, the projection of two adjacent layers of fiber filaments along the vertical direction of the sheets forms a mesh structure.

5. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: in any layer, preferably, in each layer of fiber filaments, the distance between adjacent fiber filaments is 0.5 m-50 m, preferably arranged at equal intervals; and/or, the fiber filaments are arranged along any of the transverse, longitudinal or oblique direction of the surface of the sheet.

6. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said fiber filament has an arbitrary curve shape, preferably a periodically changing curve shape.

7. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the fiber filaments in the same layer have the same shape, and preferably, the fiber filaments in all layers have the same shape.

8. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said fiber filaments have a diameter of 0.5-50 m, preferably 0.5-5 m, more preferably 0.5-1 km.

9. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said oleophilic fiber filament is at least one of a polyester fiber filament, a nylon fiber filament, a stainless steel fiber filament, a polyurethane fiber filament, a polypropylene fiber filament, a polyacrylonitrile fiber filament, a polyvinyl chloride fiber filament, or an oleophilically surface-treated fiber filament material.

10. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said hydrophilic fiber filament is selected from one or more of a high molecular polymer containing at least one hydrophilic group in its main chain or side chain or a fiber filament that has been hydrophilically treated with a physical or chemical method.

11. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said hydrophilic fiber filament is selected from one or more of glass fiber filament, ceramic fiber filament, polypropylene fiber, polyamide fiber or acrylic fiber.

12. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: said sheet has a thickness of 0.05 mm-5 mm, preferably 0.1-1.5 mm.

13. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the ratio by weight of the oleophilic fiber filament to the hydrophilic fiber filament filled in the crevices between said adjacent sheets is 1:50-1:1.

14. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the hydrophilic fiber filaments in any layer are uniformly distributed in the oleophilic fiber filaments.

15. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the ratio by weight of the oleophilic fiber filament to the hydrophilic fiber filament in any layer is 1:50-1:1.

16. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the sheet is of any one or more of metal, ceramics, organic glass, or polyester material.

17. The microchannel liquid-liquid mixing device according to any of the aforementioned claims, which is characterized in that: the shape of the sheet is any one of rectangle, square, polygon, circle, ellipse, or sector.

18. A liquid-liquid reaction apparatus, which includes a microchannel mixing device I, a microchannel mixing device II, and a reactor; said microchannel mixing device I has a tube-shell type structure, and a bundle of inorganic membrane tubes is arranged inside the shell; the inlet end of the bundle of inorganic membrane tubes is communicated with the first liquid phase feeding pipeline, the cavity in the shell outside of the bundle of inorganic membrane tubes is communicated with a second liquid phase feeding pipeline, and the outlet end of the bundle of inorganic membrane tubes is an outlet for a mixed material I; the microchannel mixing device I is used for feeding a first liquid phase and a second liquid phase to form a mixed material I, the second liquid phase diffuses into the first liquid phase inside the inorganic membrane tube through porous channels in the tube wall of the inorganic membrane tube from the cavity in the shell, and under the action of the shearing force of the first liquid phase having a high flow rate in the tube, two liquid phases forms a homogeneous mixed material I, which is used as the main reaction feed; preferably, a control device is provided in the microchannel mixing device I so that the ratio of the first liquid phase to the second liquid phase is greater than or less than (preferably greater than) the theoretical ratio of the first liquid phase to the second liquid phase of the reaction; said microchannel mixing device II is a microchannel liquid-liquid mixing device according to claim 1, which includes a microchannel component and a shell, the microchannel component is fixed inside the shell, an inlet is provided at one end of the shell for feeding the first liquid phase and the second liquid phase, and an outlet is provided at the other end for discharging a mixed material II; said microchannel component comprises multiple stacked sheets and oleophilic and hydrophilic fiber filaments filled in the crevices between adjacent sheets, wherein the fiber filaments form several microchannels between them, and the fiber filaments are clamped and fixed by the sheets; the microchannel mixing device II is used for the first liquid phase and the second liquid phase to form the mixed material II, and the first liquid phase and the second liquid phase are cut by fiber filaments and mixed in the microchannel mixing device II to form the mixed material II; wherein preferably a control device is provided in the microchannel mixing device II so that the ratio of the first liquid phase to the second liquid phase is not greater than or not less than (preferably not greater than) the theoretical ratio of the first liquid phase to the second liquid phase of the reaction; the top, the bottom, or the side of the reactor is provided with feed inlet(s), while the bottom, the top, or the side is provided with discharge outlet(s); the reactor body is provided with an inlet for the mass transfer-enhancing material; in principle, the inlet for the mass transfer-enhancing material can be provided at any position within the reactor; the outlet for the mixed material I of the microchannel mixing device I is connected to the feed inlet through pipeline(s), and the outlet for the mixed material II of the microchannel mixing device II is connected to the inlet for the mass transfer-enhancing material.

19. The liquid-liquid reaction apparatus according to claim 18, which is characterized in that: the bundle of inorganic membrane tubes of said microchannel mixing device I is of one or more of ceramic membrane, metal membrane, metal/ceramic composite membrane, alloy membrane, molecular sieve composite membrane, zeolite membrane glass membrane or the like; the tube wall of the inorganic membrane tube has a hole diameter of 10 nm-1 m.

20. An olefin hydration reaction process by using the liquid-liquid reaction apparatus according to claim 18, which is characterized in that said olefin hydration reactor is a fix bed reactor, the inlet for the mass transfer-enhancing material is provided between two adjacent catalyst beds; the catalyst bed is filled with an olefin hydration catalyst; one or more olefin hydration reactors can be provided as required, when more than one reactor is provided, the reactors are connected in parallel or in series; one or more catalyst bed(s) are provided in the reactor.

21. The olefin hydration reaction according to claim 20, which is characterized in that: a mixed material I is formed by mixing an olefin phase and an aqueous phase with an aqueous phase/olefin phase ratio of 1 with the microchannel mixing device I and sent to the bottom of the olefin hydration reactor as the main reaction material; and a mixed material II is formed by mixing an olefin phase and an aqueous phase with an aqueous phase/olefin phase ratio of <1 with a microchannel mixing device II and introduced to the reactor as the mass transfer-enhancing material; the mixed material I and the mixed material II undergo the olefin hydration reaction in the catalyst bed(s), and the reaction products flow out from the outlet at the top of the reactor and enter the next separation unit.

22. The olefin hydration reaction process according to claim 20, which is characterized in that the operation conditions of microchannel mixing device I generally are as follows: the temperature is normal temperature to 250 C., pressure is 1.0-10.0 MPaG; the operation conditions of microchannel mixing device II generally are as follows: the temperature is normal temperature to 200 C., the pressure is 1.0-10.0 MPaG.

23. The olefin hydration reaction process according to claim 20, which is characterized in that the olefin phase is generally any one of ethylene, propylene, n-butene, isobutene, isopentene, cyclohexene or the like.

24. The olefin hydration reaction process according to claim 20, which is characterized in that the olefin hydration reactor generally adopts a form of bottom-in and top-out.

25. The olefin hydration reaction process according to claim 20, which is characterized in that in the microchannel mixing device I, the aqueous phase/olefin phase ratio by mass is generally 2:1-20:1, and in the microchannel mixing device II, the aqueous phase/olefin phase ratio by mass is generally 1:20-1:1.

26. The olefin hydration reaction process according to claim 20, which is characterized in that in the mixed material I formed by said microchannel mixing device I, the olefin droplets have a particle size d1 of 100-900 m and preferably have the disperse uniformity of 80%; in the mixed material II formed by said microchannel mixing device II, the olefin droplets have a particle size d2 of less than 100 m and preferably 0.1-50 m.

27. The olefin hydration reaction process according to claim 20, which is characterized in that the addition amount of the mixed material II is 1 wt %-30 wt % of the total materials in the reactor (the total amount of the olefin phase and the aqueous phase); when the mixed material II is divided into multiple streams for the addition, it is preferable to gradually increase the addition amount of each stream along the flow direction of the materials in the reactor (for example, the addition amount of the latter stream increases by 5-20 wt % relative to the addition amount of the former stream); and/or, preferably the aqueous phase/olefin phase ratio along the flow direction of the materials in the reactor is reduced or unchanged.

28. The olefin hydration reaction process according to claim 20, which is characterized in that a catalyst with acid catalytic function, such as mineral acid, benzene sulfonic acid, ion exchange resin, molecular sieve, and other types of catalysts, is generally used in the catalyst bed(s) of the olefin hydration reactor.

29. The olefin hydration reaction process according to claim 20, which is characterized in that the conditions of the olefin hydration reaction is generally as follows: the temperature is 80-250 C., the pressure is 1.0-10.0 MPaG, and the space velocity is 0.1-3.0 h.sup.1.

30. A transesterification process performed by using the liquid-liquid reaction device according to claim 18, which is characterized in that the reactor is a tank reactor, a column reactor, a tubular reactor, or an improved form of the aforementioned reactors; one or more reactors can be provided as required, and the reactors can be connected in parallel or series; at least one mixed material formed by the microchannel mixing device II is introduced as the mass transfer-enhancing material.

31. The transesterification process according to claim 30, which is characterized in that: a mixed material I is formed by mixing two phases of low carbon alcohol and triglyceride having the molar ratio of low carbon alcohol to triglyceride of 3 with the microchannel mixing device I and sent to the transesterification reactor as the main reaction material; and a mixed material II is formed by mixing two phases of low carbon alcohol and triglyceride having the molar ratio of low carbon alcohol to triglyceride of <3 with a microchannel mixing device II and introduced to the reactor as the mass transfer-enhancing material; the mixed material I and the mixed material II undergo the transesterification reaction in the reactor, and the reaction products flow out from the outlet of the reactor and enter the separation unit.

32. The transesterification process according to claim 30, which is characterized in that: the operation conditions of the microchannel mixing device I generally include: the temperature is normal temperature to 150 C., the pressure is 0.5-3.0 MPaG; the operation conditions of the microchannel mixing device II generally include: the temperature is normal temperature to 150 C., the pressure is 0.5-3.0 MPaG, in particular, the amount of the liquid catalyst is 0.5%-10% of the amount of the oil/fat raw material.

33. The transesterification process according to claim 30, which is characterized in that: the oil/fat raw material is a triglyceride, mainly derived from animal oils or vegetable oils, including the oil and fat having an acid value of 0-130 mg KOH/g (including gutter oil), and refined vegetable oils such as jatropha oil, rapeseed oil, soybean oil, flax oil, peanut oil, palm oil, and tea seed oil are preferred.

34. The transesterification process according to claim 30, which is characterized in that: the low carbon alcohol is an aliphatic alcohol having the carbon number of 1-6, and can be a single aliphatic alcohol, or a mixture containing one or more aliphatic alcohols, preferably methanol.

35. The transesterification process according to claim 30, which is characterized in that: a basic catalyst is used in the transesterification, and said basic catalyst can be one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, calcium hydroxide, magnesium oxide, calcium oxide, barium oxide and diethylamine.

36. The transesterification process according to claim 30, which is characterized in that: the reaction conditions of the transesterification are as follows: the reaction pressure is 0.5-2.0 MPaG, the reaction temperature is 100-150 C.; the molar ratio of low carbon alcohol to triglyceride is 1:3-1:15, and the amount of the basic catalyst is 0.5%-10% by weight of the amount of the oil/fat raw material.

37. The transesterification process according to claim 30, which is characterized in that: a liquid catalyst is optionally contained in the mass transfer-enhancing material II.

38. The transesterification process according to claim 30, which is characterized in that: the total residence time in the transesterification reactor is 0.5-7 hours, preferably 0.5-3.5 hours.

39. The transesterification process according to claim 30, which is characterized in that: in the microchannel mixing device I, the low carbon alcohol/triglyceride molar ratio is generally 3:1-15:1, and in the microchannel mixing device II, the alcohol/oil molar ratio is generally 1:10-1:0.33.

40. The transesterification process according to claim 30, which is characterized in that: in the mixed material I formed by said microchannel mixing device I, the triglyceride droplets have a particle size d1 of 100-900 m and preferably have the disperse uniformity of 80%; and in the mixed material II formed by said microchannel mixing device II, the triglyceride droplets have a particle size d2 of less than 100 m and preferably 0.1-50 m.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] FIG. 1A is a schematic diagram of the olefin hydration reaction apparatus of the present invention.

[0060] FIG. 1B is a schematic diagram of the microchannel component in the microchannel mixing device II,

[0061] In FIGS. 1A and 1B: [0062] 101 Olefin phase I [0063] 102 Aqueous phase I [0064] 103 Microchannel mixing device I [0065] 104 Shell of the tube-shell type inorganic membrane mixer [0066] 105 Bundle of inorganic membrane tubes [0067] 106 Shell space outside the bundle of inorganic membrane tubes [0068] 107 Mixed material I [0069] 108 Olefin phase II [0070] 109 Aqueous phase II [0071] 110 Microchannel mixing device II [0072] 111 Microchannel component [0073] 112 Microchannel shell [0074] 113 Microchannel sheet [0075] 114 Crevice between microchannel sheets [0076] 115 Hydrophilic fiber filaments [0077] 116 Oleophilic fiber filaments [0078] 117 Mixed material II [0079] 118 Mass transfer-enhancing material introduced between the first and second catalyst beds [0080] 119 Mass transfer-enhancing material introduced between the second and third catalyst beds [0081] 120 Mass transfer-enhancing material introduced between the third and fourth catalyst beds [0082] 121 Olefin hydration reactor [0083] 122 First catalyst bed [0084] 123 Second catalyst bed [0085] 124 Third catalyst bed [0086] 125 Fourth catalyst bed [0087] 126 Feed distributor for the first catalyst bed [0088] 127 Feed distributor for the second catalyst bed [0089] 128 Feed distributor for the third catalyst bed [0090] 129 Feed distributor for the fourth catalyst bed [0091] 130 Olefin hydration reaction product

[0092] FIG. 2A is a schematic diagram of the reaction apparatus for producing biodiesel with transesterification of the present invention.

[0093] FIG. 2B is a schematic diagram of the microchannel component in the microchannel mixing device II,

[0094] In FIGS. 2A and 2B: [0095] 201 Triglyceride I [0096] 202 Low carbon alcohol and liquid catalyst I [0097] 203 Microchannel mixing device I [0098] 204 Shell of the tube-shell type inorganic membrane mixer [0099] 205 Bundle of inorganic membrane tubes [0100] 206 Shell space outside the bundle of inorganic membrane tubes [0101] 207 Mixed material I [0102] 208 Triglyceride II [0103] 209 Low carbon alcohol and liquid catalyst II [0104] 210 Microchannel mixing device II [0105] 211 Microchannel component [0106] 212 Microchannel shell [0107] 213 Microchannel sheet [0108] 214 Crevice between microchannel sheets [0109] 215 Hydrophilic fiber filaments [0110] 216 Oleophilic fiber filaments [0111] 217 Mixed material II [0112] 218 Mass transfer-enhancing material introduced into the transesterification reactor [0113] 219 Mass transfer-enhancing material introduced into the transesterification reactor [0114] 220 Mass transfer-enhancing material introduced into the transesterification reactor [0115] 221 Transesterification reactor [0116] 222 Material distributor [0117] 223 Transesterification reaction product

DETAILED DESCRIPTION

[0118] The following provides a detailed explanation of the present invention in conjunction with the accompanying drawings and examples, without limiting the present invention.

[0119] FIG. 1A is taken as an example to illustrate the olefin hydration reaction apparatus and the olefin hydration process of the present invention:

[0120] Firstly, the olefin phase 101 and the aqueous phase 102 are introduced into the microchannel mixing device 1103 in the aqueous phase/olefin phase ratio of 1, forming a mixed material 1107. The olefin phase 101 is introduced into the shell space 106 of the microchannel mixing device I 103, and the aqueous phase 102 is introduced into the inorganic membrane tube bundle 105 of the microchannel mixing device I 103. The olefin phase 101 penetrates into the tube through the tube wall of the inorganic membrane tube from the outside. Under the high-speed shear action of water, the two undergo the forced mixing to form the mixed material I 107, As the main reaction material, it enters the olefin hydration reactor 121 and undergoes a reaction in the catalyst bed layer. Another part of olefin phase II 108 and the aqueous phase II 109 are introduced into the microchannel mixing device II 110 at the aqueous phase/olefin phase ratio of <1. After passing through the crevice 114 between the microchannel sheets 113 in the microchannel component 111 provided in the microchannel mixing device II 110, the hydrophilic fiber filaments 115 and the oleophilic fiber filaments 116 filled between the crevice 114 are continuously cut multiple times to form a mixed material II 117, which is introduced as the mass transfer-enhancing material 118 between the first and second catalyst beds, the mass transfer-enhancing material 119 between the second and third catalyst beds, the mass transfer-enhancing material 120 between the third and fourth catalyst beds respectively, between the catalyst beds of the olefin hydration reactor 121, enabling the mass transfer-enhancing material to quickly supplement the olefin molecules consumed during the reaction process, thus achieving the purpose of enhancing the mass transfer. After the completion of the olefin hydration reaction, the reaction product 130 leaves.

[0121] The olefin hydration reactor of the present invention is applied to the hydration reactions of propylene, n-butene, isobutene, and cyclohexene, respectively. The specific reaction conditions can be found in Comparative Example 1-1, Comparative Example 1-2, Comparative Example 1-3, Comparative Examples 1-4, Example 1-1, Example 1-2, Example 1-3, Example 1-4, Example 1-5, Example 1-6. The olefin raw materials are commercially available, and their specific properties are shown in Table 1-1, Table 1-2, and Table 1-3. Among them, the catalyst used for propylene hydration is the DIAP type catalyst produced by Dandong Mingzhu Special Resin Co., Ltd., the catalyst used for n-butene hydration is the DNW-JJ type catalyst produced by Dandong Mingzhu Special Resin Co., Ltd., the catalyst used for isobutene hydration is the DT-017 type catalyst produced by Dandong Mingzhu Special Resin Co., Ltd., and the catalyst used for cyclohexene hydration is the Amberlyst 36 type resin catalyst.

TABLE-US-00001 TABLE 1-1 Composition of propylene raw material Item Component Content, wt % 1 propylene 95.32 2 propane 3.43 3 butane 0.57 4 iso-butane 0.26 5 2-butene 0.38

TABLE-US-00002 TABLE 1-2 Composition of n-butene raw material Item Component Content, wt % 1 propane 0.02 2 iso-butane 9.69 3 trans-2-butene 14.22 4 cis-2-butene 5.77 5 propylene 0.01 6 n-butane 11.68 7 1-butene 58.48 8 iso-butene 0.13

TABLE-US-00003 TABLE 1-3 Composition of isobutene raw material Item Component Content, wt % 1 propane 0.22 2 propylene 0.35 3 iso-butane 0.43 4 iso-butene 98.35 5 trans-butene 0.14 6 iso-pentane 0.15 7 cis-butene 0.25 8 Others 0.11

Comparative Example 1-1

[0122] Using a propylene raw material from Table 1-1, isopropanol was prepared by the hydration reaction of propylene with water under the action of a catalyst. The propylene raw material and water were mixed through a conventional static mixer, model SL-1.6/25-10.0-200, and the mixed material entered the propylene hydration reactor for the hydration reaction. The mixing conditions were as follows: the temperature was 155 C., and the pressure was 8.0 MPa. The reactor was a regular up-flow reactor, which was equipped with three stages of the catalyst beds. The inlet of each stage of the catalyst bed was equipped with a distribution sieve plate, with a sieve plate hole diameter of 3 mm. A mixture of olefin and water was introduced into the bottom of the olefin hydration reactor, evenly distributed along the cross-section of the reactor with the distribution sieve plate, entered the catalyst bed for the olefin hydration reaction, and finally left the olefin hydration reactor through the discharge outlet at the top of the reactor.

[0123] The reaction products were obtained from propylene raw material in Table 1-1 through the propylene hydration reactor. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Comparative Example 1-2

[0124] Using a n-butene raw material from Table 1-2, sec-butanol was prepared by the hydration reaction of n-butene with water under the action of a catalyst. The n-butene raw material and water were mixed three times continuously through a conventional static mixer, model SL-1.6/25-10.0-250, and the mixed material entered the n-butene hydration reactor for the hydration reaction. The mixing conditions were as follows: the temperature was 175 C., and the pressure was 8.0 MPa. The reactor was a regular up-flow reactor, which was equipped with four stages of the catalyst beds. The inlet of each stage of the catalyst bed was equipped with a distribution sieve plate, with a sieve plate hole diameter of 2 mm. A mixture of n-butene and water was introduced into the bottom of the olefin hydration reactor, evenly distributed along the cross-section of the reactor with the distribution sieve plate, entered the catalyst bed for the olefin hydration reaction, and finally left the olefin hydration reactor through the discharge outlet at the top of the reactor.

[0125] The reaction products were obtained from n-butene raw material in Table 1-2 through the n-butene hydration reactor. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Comparative Example 1-3

[0126] Using an isobutylene raw material from Table 1-3, tert-butanol was prepared by the hydration reaction of isobutene with water under the action of a catalyst. The isobutene raw material and water were mixed through a conventional static mixer, model SL-1.6/25-5.0-200, and the mixed material entered the isobutene hydration reactor for the hydration reaction. The mixing conditions were as follows: the temperature was 105 C., and the pressure was 2.6 MPa. The reactor was a regular up-flow reactor, which was equipped with two stages of the catalyst beds. The inlet of each stage of the catalyst bed was equipped with a distribution sieve plate, with a sieve plate hole diameter of 3 mm. A mixture of iso-butene and water was introduced into the bottom of the olefin hydration reactor, evenly distributed along the cross-section of the reactor with the distribution sieve plate, entered the catalyst bed for the olefin hydration reaction, and finally left the olefin hydration reactor through the discharge outlet at the top of the reactor.

[0127] The reaction products were obtained from iso-butene raw material in Table 1-3 through the iso-butene hydration reactor. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-1

[0128] Using a propylene raw material from Table 1-1, isopropanol was prepared by the hydration reaction of propylene with water under the action of a catalyst. A mixed material I was formed by introducing into the microchannel mixing device I at the aqueous phase/olefin phase ratio by mass of 12:1, and sent as the main reaction material to the olefin hydration reactor for the reaction in the catalyst bed(s).

[0129] A mixed material II was formed by introducing into the microchannel mixing device II at the aqueous phase/olefin phase ratio by mass of 1:7.5, and introduced as the mass transfer-enhancing material between the catalyst beds to enhance the olefin hydration reaction process. The reaction effluent left the reactor and entered the next separation unit.

[0130] The used reactor was the reactor of the present invention, with bottom-in and top-out. Three catalyst beds were provided in the reactor. Two streams of mass transfer-enhancing mixed material II were introduced between the first/second catalyst beds and between the second/third catalyst beds, respectively. The addition amount of mixed material II was 3.6 wt % of the total of the materials to the reactor (the total of olefin phase and aqueous phase). The proportion of the mixed material II introduced between the first/second catalyst beds to that introduced between the second/third catalyst beds was 1:1.5. In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.2 mm. Five layers of metal fiber filaments having a diameter of 5 m and one layer of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m. The fiber filament had a curve shape with periodic changes in wavy lines. The operation conditions of microchannel mixing device I were as follows: the temperature was 150 C., the pressure was 7.5 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 125 C., the pressure was 7.0 MPaG.

[0131] The reaction products were obtained from propylene raw material in Table 1-1. The propylene hydration reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-2

[0132] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 1-1. Different from Example 1-1, more mild reaction conditions were used in this example. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-3

[0133] Using a n-butene raw material from Table 1-2, sec-butanol was prepared by the hydration reaction of n-butene with water under the action of a catalyst. A mixed material I was formed by introducing into the microchannel mixing device I at the aqueous phase/olefin phase ratio by mass of 3:1, and sent as the main reaction material to the olefin hydration reactor for the reaction in the catalyst bed(s). A mixed material II was formed by introducing into the microchannel mixing device II at the aqueous phase/olefin phase ratio by mass of 1:2, and introduced as the mass transfer-enhancing material between the catalyst beds to enhance the olefin hydration reaction process. The reaction effluent left the reactor and entered the next separation unit.

[0134] The used reactor was the reactor of the present invention, with bottom-in and top-out. Four catalyst beds were provided in the reactor. The mass transfer-enhancing mixed material II was introduced between the first/second catalyst beds, between the second/third catalyst beds, and between the third/fourth catalyst beds, respectively. The addition amount of mixed material II was 4.0 wt % of the total of the materials to the reactor (the total of olefin phase and aqueous phase). The proportion of the mixed material II introduced between the first/second catalyst beds to that introduced between the second/third catalyst beds to that introduced between the third/fourth catalyst beds was 1:1.2:1.5.

[0135] In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.0 mm. Three layers of glass fiber filaments having a diameter of 1 m and one layer of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m. The fiber filament had a curve shape with periodic changes in wavy lines. The operation conditions of microchannel mixing device I were as follows: the temperature was 175 C., the pressure was 7.8 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 135 C., the pressure was 7.0 MPaG.

[0136] n-Butene raw material were shown in Table 1-2. The hydration reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-4

[0137] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 1-3. Different from Example 1-3, more mild reaction conditions were used in this example. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-5

[0138] Using an isobutylene raw material from Table 1-3, tert-butanol was prepared by the hydration reaction of isobutene with water under the action of a catalyst. A mixed material I was formed by introducing into the microchannel mixing device I at the aqueous phase/olefin phase ratio by mass of 4:1, and sent as the main reaction material to the olefin hydration reactor for the reaction in the catalyst bed(s). A mixed material II was formed by introducing into the microchannel mixing device II at the aqueous phase/olefin phase ratio by mass of 1:1.62, and introduced as the mass transfer-enhancing material between the catalyst beds to enhance the olefin hydration reaction process. The reaction effluent left the reactor and entered the next separation unit.

[0139] The used reactor was the reactor of the present invention, with bottom-in and top-out. Two catalyst beds were provided in the reactor. The mass transfer-enhancing mixed material II was introduced between the first/second catalyst beds. The addition amount of mixed material II was 2.0 wt % of the total of the materials to the reactor (the total of olefin phase and aqueous phase).

[0140] In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.5 mm. Eight layers of stainless steel fiber filaments having a diameter of 5 m and two layers of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m. The fiber filament had a curve shape with periodic changes in wavy lines. The operation conditions of microchannel mixing device I were as follows: the temperature was 105 C., the pressure was 2.8 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 85 C., the pressure was 2.1 MPaG.

[0141] Isobutene raw material were shown in Table 1-3. The hydration reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

Example 1-6

[0142] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 1-5. Different from Example 1-5, more mild reaction conditions were used in this example. The reaction conditions, the residence time, and the raw material conversion rate were shown in Table 1-4.

TABLE-US-00004 TABLE 1-4 Reaction conditions and results Once- through conversion Total mass of raw Temperature, Pressure, VHSP, ratio of materials, Selectivity, No C. MPaG h.sup.1 aqueous/olefin wt % % 1 Comparative 155-160 8.0 0.25 15 64.5 92.3 Example1-1 2 Comparative 175-180 8.0 1.0 2.5 6.3 96.2 Example1-2 3 Comparative 105-110 2.5 1.0 3 85.6 97.5 Example1-3 4 Example 1-1 150-156 7.0 0.32 10 94.7 99.3 5 Example 1-2 130-135 6.0 0.35 10 94.2 99.3 6 Example 1-3 175-180 7.5 1.5 2.0 50.2 98.3 7 Example 1-4 136-142 6.3 1.6 2.0 49.6 98.4 8 Example 1-5 105-111 2.5 1.2 2.2 98.2 99.2 9 Example 1-6 100-106 2.2 1.4 2.0 97.8 99.2

[0143] The dispersion size and dispersion effect of olefin droplets in water in the process of the present invention were measured by using a high-speed camera, and by selecting several characteristic particles to obtain the particle uniformity of the dispersed phase. The smaller the particle size, the higher the uniformity, the better the dispersion and mixing effect. Therefore, the measurement method for the mixing and dispersion effect in the above Examples and Comparative Examples was to mix the dispersed phase (olefin phase) and the continuous phase (aqueous phase) by using different mixing and dispersion methods (such as conventional static mixer, Microchannel mixing system I and Microchannel mixing system II in the reactor of the present invention) under the same conditions. For each method, at least 10 sets of mixed material samples were obtained, and the UK IX i-SPEED 5 high-speed camera was used to capture the size of the dispersed phase particles in the mixed material samples. The particles in the photo were summed, the percentage contents of the particles of various sizes were calculated to obtain the normal distribution diagram of particles of various sizes, and then obtain the particle uniformity.

[0144] From the above examples and comparative examples of the present invention, it could be seen that in case that the olefin hydration reaction apparatus and the reaction process of the present invention are used, due to the introduction of the main reaction material from the bottom of the reactor, the reaction feed maintains two phases to be homogeneous in the reactor, providing a prerequisite for the high conversion rate of the olefin hydration reaction. Then another part of the olefin and water passed through the microchannel mixing device II under the aqueous phase/olefin phase ratio of <1 to form the mixed material II, which was introduced as the mass transfer-enhancing material between catalyst beds. Due to the small size of olefin droplets and the concentrated olefin molecules, the mixed material II can quickly break through the phase interface and supplement the olefin phase consumed in the reaction, greatly enhancing the mass transfer of the entire reaction process, improving the olefin hydration reaction rate and raw material once-through conversion, reducing the aqueous phase/olefin phase ratio, reducing the number of reactors or the reaction residence time, and improving the production efficiency of the olefin hydration apparatus.

[0145] FIG. 2A is taken as an example to illustrate the reaction apparatus and process for producing biodiesel with transesterification of the present invention:

[0146] Firstly, the triglyceride 201 and low carbon alcohol and liquid catalyst 202 are introduced into the microchannel mixing device I 203 in the low carbon alcohol/triglyceride molar ratio of 3, forming a mixed material I 207. The triglyceride 201 is introduced into the shell space 206 of the microchannel mixing device 1203, and the low carbon alcohol and liquid catalyst 202 is introduced into the inorganic membrane tube bundle 205 of the microchannel mixing device I 203. The triglyceride 201 penetrates into the tube through the tube wall of the inorganic membrane tube from the outside. Under the high-speed shear action of the low carbon alcohol and liquid catalyst, the two undergo the forced mixing to form the mixed material I 207, As the main reaction material, it enters the transesterification reactor 221 and undergoes the transesterification reaction in the reactor. Another part of triglyceride II 208 and the low carbon alcohol and liquid catalyst II 209 are introduced into the microchannel mixing device II 210 at the low carbon alcohol/triglyceride molar ratio of <3. After passing through the crevice 214 between the microchannel sheets 213 in the microchannel component 211 provided in the microchannel mixing device II 210, the hydrophilic fiber filaments 215 and the oleophilic fiber filaments 216 filled between the crevice 214 are continuously cut multiple times to form a mixed material II 217, which is introduced as the mass transfer-enhancing material 218, the mass transfer-enhancing material 219, and the mass transfer-enhancing material 220 respectively into the transesterification reactor 221, enabling the mass transfer-enhancing materials to quickly supplement the triglyceride consumed during the reaction process, thus achieving the purpose of enhancing the mass transfer. After the completion of the transesterification reaction, the reaction product 222 leaves. The raw material triglyceride used in the examples and comparative examples of the present invention is tung oil, and its properties are shown in Table 1.

TABLE-US-00005 TABLE 1 Properties of raw material No Item Index 1 Color (Lovibond colorimeter 1 inch Yellow: 35, Red: 3.0 cuvette) 2 Odor Inherent normal odor of tung oil, without off-flavor 3 Transparency (stood for 24 hours, Transparent 20 C.) 4 Acid value/mg(KOH) .Math. g.sup.1 3.0 5 Moisture and volatile matter, % 0.10 6 Mechanical impurity, % No

Comparative Example 2-1

[0147] The conventional transesterification apparatus and reaction process for biodiesel products were used. The raw materials for transesterification were the oil/fat raw material, methanol and basic catalyst (see Table 1 for the properties of the oil/fat raw material). First, the oil/fat raw material, methanol and basic catalyst were introduced into a stirred tank for stirring and mixing for 15-20 minutes, and then pumped with a feeding pump into a two-stage reactor to perform the transesterification, wherein the first stage reactor was a column reactor with a size of 2001200 mm, the second stage reactor was a tube reactor with a size of 8012800 mm.

[0148] The operation conditions of the reactor were as follows: [0149] Feeding rate of the oil/fat raw material: 1.5 kg/h; [0150] The reaction temperature was 120 C.-125 C.; [0151] The reaction pressure was 2.0 MPaG; [0152] Alcohol/oil molar ratio: 8-10 (the molecular weight of the oil and fat was equivalent to 880, the same for the following) [0153] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%.

[0154] Under the reaction conditions, the raw material conversion at the outlet of the first stage reactor was 75.2%, the raw material conversion at the outlet of the second stage reactor was 87.4%; the first-stage transesterification residence time (based on the total of the materials) was 2.02 hours, the second-stage transesterification residence time (based on the total of the materials) was 3.44 hours.

Comparative Example 2-2

[0155] The conventional transesterification apparatus and reaction process for biodiesel products were used. The raw materials for transesterification were the oil/fat raw material, methanol and basic catalyst (see Table 1 for the properties of the oil/fat raw material). First, the oil/fat raw material, methanol and basic catalyst were introduced into a collision-type reactor for mixing by collision for 5-10 minutes, and then pumped with a feeding pump into a two-stage reactor to perform the transesterification, wherein the first stage reactor was a column reactor with a size of 2001200 mm, the second stage reactor was a tube reactor with a size of 8012800 mm.

[0156] The operation conditions of the reactor were as follows: [0157] Feeding rate of the oil/fat raw material: 1.8 kg/h; [0158] The reaction temperature was 120 C.-125 C.; [0159] The reaction pressure was 2.0 MPaG; [0160] Alcohol/oil molar ratio: 8-10 (the molecular weight of the oil and fat was equivalent to 880) [0161] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%.

[0162] Under the reaction conditions, the raw material conversion at the outlet of the first stage reactor was 87.2%, the raw material conversion at the outlet of the second stage reactor was 90.5%; the first-stage transesterification residence time (based on the total of the materials) was 1.68 hours, the second-stage transesterification residence time (based on the total of the materials) was 2.87 hours.

Example 2-1

[0163] The transesterification process of the present invention was used. The raw materials for transesterification were the oil/fat raw material, methanol and basic catalyst (see Table 1 for the properties of the oil/fat raw material). First, the oil/fat raw material, methanol and basic catalyst were introduced to the microchannel mixing device I, wherein the molar ratio of the oil/fat raw material/methanol was 6:1, the oil/fat raw material was introduced into the shell side of the microchannel mixing device I, and methanol and liquid basic catalyst were introduced into the tube side of the microchannel mixing device I, the mixed material I formed with the microchannel mixing device I was used as the main reaction material to enter a two-stage transesterification reactor to perform the transesterification, wherein the first stage reactor was a column reactor with a size of 200800 mm, the second stage reactor was a tube reactor with a size of 806400 mm a mixed material II was formed from the oil/fat raw material and methanol in the molar ratio of 1:1 with the microchannel mixing device II, and introduced as the mass transfer-enhancing material into the column reactor and the tubular reactor respectively to enhance the transesterification process. The reaction effluent left the reactor and entered the next separation unit.

[0164] In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.2 mm. Five layers of metal fiber filaments having a diameter of 5 m and one layer of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m.

[0165] The fiber filament had a curve shape with periodic changes in wavy lines.

[0166] The operation conditions of the transesterification process were as follows: [0167] Feeding rate of the oil/fat raw material: 3.6 kg/h; [0168] Reaction temperature: 120 C.-125 C.; [0169] Reaction pressure: 2.0 MPaG; [0170] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%;

[0171] The mass transfer-enhancing material added to the column reactor comprised 25.6 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 5.2 wt % of the total reaction feed.

[0172] The operation conditions of microchannel mixing device I were as follows: the temperature was 120-125 C., the pressure was 2.0 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 120 C., the pressure was 2.0 MPaG.

[0173] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 96.30%, the raw material conversion in the second-stage transesterification was 98.7%; the first-stage transesterification residence time was 0.87 hours, the second-stage transesterification residence time was 1.11 hours.

Example 2-2

[0174] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 2-1. Different from Example 2-1, in this example, on the one hand, the transesterification conditions were changed, on the other hand, the introduction position and amount of the mass transfer-enhancing material were appropriately adjusted.

[0175] The operation conditions of the transesterification process were as follows: [0176] Feeding rate of the oil/fat raw material: 3.6 kg/h; [0177] Reaction temperature: 120 C.-125 C.; [0178] Reaction pressure: 1.8 MPaG; [0179] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%;

[0180] The mass transfer-enhancing material added to the column reactor comprised 16.6 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 8.0 wt % of the total reaction feed.

[0181] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 97.10%, the raw material conversion in the second-stage transesterification was 98.8%; the first-stage transesterification residence time was 0.87 hours, the second-stage transesterification residence time was 1.11 hours.

Example 2-3

[0182] The transesterification process of the present invention was used. The raw materials for transesterification were the oil/fat raw material, methanol and basic catalyst (see Table 1 for the properties of the oil/fat raw material). First, the oil/fat raw material, methanol and basic catalyst were introduced to the microchannel mixing device I, wherein the molar ratio of the oil/fat raw material/methanol was 5:1, the oil/fat raw material was introduced into the shell side of the microchannel mixing device I, and methanol and liquid basic catalyst were introduced into the tube side of the microchannel mixing device I, the mixed material I formed with the microchannel mixing device I was used as the main reaction material to enter a two-stage transesterification reactor to perform the transesterification, wherein the first stage reactor was a column reactor with a size of 200800 mm, the second stage reactor was a tube reactor with a size of 806400 mm; a mixed material II was formed from the oil/fat raw material and methanol in the molar ratio of 1:2 with the microchannel mixing device II, and introduced as the mass transfer-enhancing material into the column reactor and the tubular reactor respectively to enhance the transesterification process. The reaction effluent left the reactor and entered the next separation unit.

[0183] In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.0 mm. Three layers of glass fiber filaments having a diameter of 1 m and one layer of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m. The fiber filament had a curve shape with periodic changes in wavy lines.

[0184] The operation conditions of the transesterification process were as follows: [0185] Feeding rate of the oil/fat raw material: 3.6 kg/h; [0186] Reaction temperature: 120 C.-125 C.; [0187] Reaction pressure: 2.0 MPaG; [0188] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%;

[0189] The mass transfer-enhancing material added to the column reactor comprised 20.0 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 3.6 wt % of the total reaction feed.

[0190] The operation conditions of microchannel mixing device I were as follows: the temperature was 120-125 C., the pressure was 2.0 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 120 C., the pressure was 2.0 MPaG.

[0191] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 97.0%, the raw material conversion in the second-stage transesterification was 98.9%; the first-stage transesterification residence time was 1.01 hours, the second-stage transesterification residence time was 1.30 hours.

Example 2-4

[0192] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 2-3. Different from Example 2-3, in this example, on the one hand, the feed rate and the transesterification conditions were changed, on the other hand, the introduction position and amount of the mass transfer-enhancing material were appropriately adjusted.

[0193] The operation conditions of the transesterification process were as follows: [0194] Feeding rate of the oil/fat raw material: 4.0 kg/h; [0195] Reaction temperature: 120 C.-125 C.; [0196] Reaction pressure: 2.0 MPaG; [0197] The mass fraction of basic catalyst relative to the oil/fat raw material: 3.0%;

[0198] The mass transfer-enhancing material added to the column reactor comprised 22.4 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 3.2 wt % of the total reaction feed.

[0199] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 96.8%, the raw material conversion in the second-stage transesterification was 99.1%; the first-stage transesterification residence time was 1.01 hours, the second-stage transesterification residence time was 1.30 hours.

Example 2-5

[0200] The transesterification process of the present invention was used. The raw materials for transesterification were the oil/fat raw material, methanol and basic catalyst (see Table 1 for the properties of the oil/fat raw material). First, the oil/fat raw material, methanol and basic catalyst were introduced to the microchannel mixing device I, wherein the molar ratio of the oil/fat raw material/methanol was 8:1, the oil/fat raw material was introduced into the shell side of the microchannel mixing device I, and methanol and liquid basic catalyst were introduced into the tube side of the microchannel mixing device I, the mixed material I formed with the microchannel mixing device I was used as the main reaction material to enter a two-stage transesterification reactor to perform the transesterification, wherein the first stage reactor was a column reactor with a size of 200800 mm, the second stage reactor was a tube reactor with a size of 806400 mm; a mixed material II was formed from the oil/fat raw material and methanol in the molar ratio of 1:1 with the microchannel mixing device II, and introduced as the mass transfer-enhancing material into the column reactor and the tubular reactor respectively to enhance the transesterification process. The reaction effluent left the reactor and entered the next separation unit.

[0201] In the microchannel mixing device II, the sheets in the microchannel mixing component were made of stainless steel material and had a thickness of 1.5 mm. Eight layers of stainless steel fiber filaments having a diameter of 5 m and two layers of ceramic fiber filaments having a diameter of 5 m were filled in the crevices between the sheets, wherein the fiber filaments were evenly spaced with a spacing of 1 m. The fiber filament had a curve shape with periodic changes in wavy lines.

[0202] The operation conditions of the transesterification process were as follows: [0203] Feeding rate of the oil/fat raw material: 4.0 kg/h; [0204] Reaction temperature: 120 C.-125 C.; [0205] Reaction pressure: 2.0 MPaG; [0206] The mass fraction of basic catalyst relative to the oil/fat raw material: 2.5%;

[0207] The mass transfer-enhancing material added to the column reactor comprised 21.6 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 1.5 wt % of the total reaction feed.

[0208] The operation conditions of microchannel mixing device I were as follows: the temperature was 120-125 C. and a pressure of 2.0 MPaG; the operation conditions of microchannel mixing device II were as follows: the temperature was 120 C., and the pressure was 2.0 MPaG.

[0209] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 97.8%, the raw material conversion in the second-stage transesterification was 98.9%; the first-stage transesterification residence time was 0.611 hours, the second-stage transesterification residence time was 0.782 hours.

Examples 2-6

[0210] In this Example, the reaction raw materials, the reactor structure, the reaction process, the operation conditions of microchannel mixing device I, and the operation conditions of microchannel mixing device II were identical to those of Example 2-5. Different from Example 2-5, in this example, on the one hand, the feed rate and the transesterification conditions were changed, on the other hand, the introduction position and amount of the mass transfer-enhancing material were appropriately adjusted.

[0211] The operation conditions of the transesterification process were as follows: [0212] Feeding rate of the oil/fat raw material: 4.0 kg/h; [0213] Reaction temperature: 120 C.-125 C.; [0214] Reaction pressure: 1.8 MPaG; [0215] The mass fraction of basic catalyst relative to the oil/fat raw material: 3.0%;

[0216] The mass transfer-enhancing material added to the column reactor comprised 17.5 wt % of the total reaction feed, while the mass transfer-enhancing material added to the tube reactor comprised 6.4 wt % of the total reaction feed.

[0217] Under the reaction conditions, the raw material conversion in the first-stage transesterification was 97.3%, the raw material conversion in the second-stage transesterification was 98.8%; the first-stage transesterification residence time was 0.611 hours, the second-stage transesterification residence time was 0.782 hours.

[0218] The dispersion size and dispersion effect of triglyceride droplets in low carbon alcohol in the process of the present invention were measured by using a high-speed camera, and by selecting several characteristic particles to obtain the particle uniformity of the dispersed phase. The smaller the particle size, the higher the uniformity, the better the dispersion and mixing effect. Therefore, the measurement method for the mixing and dispersion effect in the above Examples and Comparative Examples was to mix the dispersed phase (triglyceride) and the continuous phase (low carbon alcohol phase) by using different mixing and dispersion methods (such as conventional static mixer, microchannel mixing system I and microchannel mixing system II in the reactor of the present invention) under the same conditions. For each method, at least 10 sets of mixed material samples were obtained, and the UK IX i-SPEED 5 high-speed camera was used to capture the size of the dispersed phase particles in the mixed material samples. The particles in the photo were summed, the percentage contents of the particles of various sizes were calculated to obtain the normal distribution diagram of particles of various sizes, and then obtain the particle uniformity.

[0219] From the above examples and comparative examples of the present invention, it could be seen that in case that the apparatus and process for producing biodiesel by transesterification of the present invention were used, due to the introduction of the mixed material I formed from oil/fat raw material, low carbon alcohol and catalyst with the microchannel mixing device I as the main reaction material into one end of the reactor, wherein the molar ratio of the low carbon alcohol to the oil/fat raw material in the mixed material I was 3, the reaction feed maintained two phases to be homogeneous in the reactor, providing a prerequisite for the high conversion rate of the transesterification reaction. Then another part of the oil/fat raw material having a molar ratio of low carbon alcohol to triglyceride of 3, and methanol and catalyst passed through the microchannel mixing device II under the molar ratio of low carbon alcohol to triglyceride of <1 to form the mixed material II, which was introduced as the mass transfer-enhancing material into the transesterification reactor. Due to the small size of the oil/fat raw material droplets and the concentrated molecules, the mixed material II could quickly break through the phase interface and supplement the oil/fat raw material consumed in the reaction, greatly enhancing the mass transfer of the entire reaction process, improving the transesterification reaction rate and raw material once-through conversion, reducing the molar ratio of low carbon alcohol to triglyceride, reducing the number of reactors or the reaction residence time, and improving the production efficiency of the apparatus for producing biodiesel with transesterification.