Enzyme catalytic reaction device and enzyme catalytic reaction method for biodiesel

Abstract

The present invention provides an enzyme catalytic reaction device and an enzyme catalytic reaction method for biodiesel. The reaction device comprises N reaction tanks connected in sequence, a feed pipeline for crude oil, a feed pipeline for alkali solution, an enzyme feed pipeline, a soft water feed pipeline and a methanol feed pipeline; N is an integer greater than 0; the reaction tank comprises a tank body, a feed port and a discharge port arranged on the tank body; the outside of the feed port of the first reaction tank is connected to an external feed main pipe, the inside of the feed port of the reaction tank is connected to an internal feed main pipe, the internal feed main pipe is connected to a feed distribution pipe, and a plurality of material injectors are connected through the feed distribution pipe. The mixed material enters the tank body through the external feed main pipe, and is subjected to a cyclic injection reaction through the material injector. The enzyme catalytic reaction device and the reaction method for biodiesel of the present invention can effectively realize the continuous reaction production of biodiesel. Not only the conversion rate of crude oil is significantly increased, the energy consumption is significantly reduced, but also the reaction capacity of the device is large.

Description

Technical Field

[0001] The invention relates to the technical field of biodiesel production, and in particular to an enzyme catalytic reaction device and an enzyme catalytic reaction method for biodiesel. Background Art

[0002] Biodiesel refers to a renewable diesel fuel that can replace petroleum diesel, which is made from oil crops such as soybeans, rapeseed, cotton, palm, wild oil plants, aquatic plant oils such as engineered microalgae, animal fats, and waste cooking oils through esterification, transesterification or thermochemical processes. Because its physical and chemical properties are very similar to those of petroleum diesel, it has gradually replaced petroleum diesel in buses and other systems in recent years, which is conducive to reducing the consumption of petroleum, a non-renewable resource.

[0003] In the prior art, the preparation process of biodiesel usually adopts an acid-base two-step method, that is, esterification-ester exchange reaction is carried out by acid and base catalysis respectively. The crude fatty acid methyl ester obtained by esterification and ester exchange reaction of the raw oil is separated from the crude glycerol after gravity sedimentation to obtain crude biodiesel. The crude biodiesel needs to be further refined to obtain biodiesel with purity that meets the national standard requirements. The refining treatment of biodiesel usually includes flash treatment, light removal treatment, distillation treatment and other processes. The above process requires that alcohol must be excessive, and the subsequent process must have a corresponding alcohol recovery device, which has high energy consumption, and the esterification product is difficult to recover. There is waste alkali liquid discharge in the production process, which seriously pollutes the environment. In addition, the industrial esterification reaction often uses liquid sulfuric acid as a catalyst for the esterification reaction. The esterification reaction process is carried out under acidic conditions, so the anti-corrosion requirements of the esterification reaction tank are high; at the same time, the addition of liquid sulfuric acid leads to an increase in sulfate ions in biodiesel, which increases the sulfur content of biodiesel. In order to remove excessive sulfur, the crude biodiesel needs to be washed or distilled, which significantly increases the wastewater content, thereby increasing the difficulty and cost of wastewater treatment and increasing the energy consumption of distillation.

[0004] The enzyme-catalyzed reaction production process is another process for preparing biodiesel. Its reaction conditions are relatively mild, there is basically no requirement for the quality of the raw oil, and the reaction product is easy to separate. At the same time, the enzyme catalyst commonly used for the ester exchange reaction between the raw oil and alcohol is lipase, which is abundant in nature. Therefore, the process of preparing biodiesel by enzyme-catalyzed reaction has been increasingly widely used. Commonly used lipases include liquid lipase, solid lipase, etc. Among them, liquid lipase is more widely used because of its simple production process and low cost.

[0005] In the prior art, enzyme-catalyzed reaction to prepare biodiesel usually adopts horizontal continuous reaction method or intermittent reaction method. Figure 7As shown, the horizontal reaction method is usually a series connection of multiple horizontal reactors, and a long stirring shaft is driven by a motor at the end to drive the scraper-type agitator in the horizontal reactor to stir. Since multiple horizontal reactors are connected in series using the same stirring shaft, the installation accuracy is high, and the stirring shaft is easily deformed, resulting in the scraper scraping against the inner wall of the horizontal reactor, and the service life of the equipment is short; there are many dead corners for stirring, resulting in low conversion rate. The series connection of multiple horizontal reactors not only requires high equipment investment and very high energy consumption, but also has high requirements on the horizontality and load-bearing capacity of the foundation, and the total cost is very high. Therefore, in the prior art, intermittent kettle reactors are more often used to intermittently produce biodiesel.

[0006] However, in the intermittent reactor reaction method, due to the limited stirring range of the stirring paddle, in order to meet the stirring requirements as much as possible and reduce the stirring dead angle, the effective volume of the intermittent reactor cannot be expanded indefinitely. If 150 tons of biodiesel are to be produced per day, due to the limited effective volume of the intermittent reactor, the number of intermittent reactors used is at least 10. This leads to a very large investment in equipment, and the simultaneous control of 10 intermittent reactors leads to great control difficulty, reduced quality stability of biodiesel, low biodiesel conversion rate and very high energy consumption. In addition, the acid value in the traditional enzyme-catalyzed reaction process is difficult to reduce to below 5, and the reaction time is usually greater than 30h. Combined with the time of intermittent feeding and discharging, the total reaction time of the traditional enzyme-catalyzed reaction process is usually up to 40h. Therefore, there are problems such as long reaction time, high acid value of crude biodiesel, and high energy consumption.

[0007] Therefore, it is necessary to develop a new enzyme-catalyzed reaction process for biodiesel to overcome the above technical defects. Summary of the invention

[0008] The first object of the present invention is to provide an enzyme catalytic reaction device for biodiesel, which can significantly improve the conversion rate of biodiesel and reduce energy consumption.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] The enzyme catalytic reaction device of biodiesel comprises N reaction tanks connected in sequence, a feed pipeline of crude oil, a feed pipeline of alkali solution, an enzyme feed pipeline, a water feed pipeline and a methanol feed pipeline, wherein N is an integer greater than 0; wherein:

[0011] The reaction tank comprises a tank body, a feed port and a discharge port arranged on the tank body; the outside of the feed port of the first reaction tank is connected to an external feed main pipe, and a feed pump is arranged on the external feed main pipe; the inside of the feed port of the reaction tank is connected to an internal feed main pipe, and the internal feed main pipe is connected to a feed distribution pipe, and a plurality of material injectors are connected through the feed distribution pipe, and the plurality of material injectors are evenly distributed in an annular manner along the inner wall of the tank body; the material injectors are arranged obliquely, and the nozzle outlet faces upward;

[0012] The feeds from the crude oil feed pipeline, the alkali solution feed pipeline, the enzyme feed pipeline, the water feed pipeline and the methanol feed pipeline are mixed to obtain a mixed material, the mixed material continuously enters the tank body through the external feed main pipe, and is subjected to a cyclic injection reaction through the material injector;

[0013] The discharge port of the last reaction tank is connected to a discharge pipeline, a discharge pump is arranged on the discharge pipeline, and the discharge pipeline is connected to a separation device; a circulation main pipe is connected to the discharge pipeline after the discharge pump, and the other end of the circulation main pipe is connected to the pipeline in front of the feed port.

[0014] It should be noted that, in the present invention, there is no limitation on how to mix the raw materials such as crude oil and enzyme into the mixed material. The above mixing process can be achieved by conventional techniques in the prior art, such as using a premixing tank to mix through a stirring device.

[0015] It should be noted that N is an integer greater than 0, that is, it can be a continuous reaction in one reaction tank. It can also be a continuous reaction in multiple reaction tanks. The number of the reaction tanks can be flexibly adjusted according to the volume of the reaction tank and the daily output of biodiesel.

[0016] It should be noted that, in the present invention, the specific form of the feed pipeline inside the tank body can be various, as long as it can achieve the goal of making a plurality of the material injectors evenly distributed in an annular shape along the inner wall of the tank body.

[0017] It should be noted that the separation equipment may be equipment commonly used in the prior art for separating glycerol from crude biodiesel, such as a separation centrifuge, a gravity settling tank, and the like.

[0018] According to the preferred technical solution of the present invention, N is an integer greater than 1, the discharge port of the previous reaction tank is connected to the feed port of the next reaction tank through an intermediate connecting pipeline; the other end of the circulation main pipe is connected to the external feed main pipe and / or the intermediate connecting pipeline.

[0019] It should be noted that, in the present invention, the other end of the circulation main pipe can be connected to the external feed main pipe and / or the intermediate connecting pipeline. That is, it can be circulated back to the front of the first reaction tank, or it can be circulated to the front of other reaction tanks. Those skilled in the art can connect the circulation main pipe with the external feed main pipe and / or the intermediate connecting pipeline according to the conversion rate of the material in the circulation main pipe.

[0020] Preferably, the material injector is a Venturi-type injector, comprising a feed connecting pipe, a mixing section, a reduced diameter section connected to the mixing section, an enlarged section connected to the reduced diameter section, and a convex head section connected to the enlarged section, wherein a plurality of injection holes are provided on the convex head section;

[0021] One end of the feed connecting pipe is connected to the feed distribution pipe, and the other end extends into the mixing section. The mixing section is provided with a suction pipe opening.

[0022] Preferably, the convex head section is spherical as a whole. More preferably, the convex head section is a spherical segment.

[0023] Preferably, the angle between the axis center line of the material ejector and the horizontal plane is 30 to 85 degrees. More preferably, the angle between the material ejector and the horizontal plane is 30 to 60 degrees.

[0024] Preferably, N is an integer of 1-6.

[0025] Preferably, the feed distribution pipe is an annular distribution pipe arranged along the inner wall of the tank body; the end of the internal feed main pipe extends into the center of the tank body and is connected to the internal feed branch pipe, and the ends of the internal feed branch pipes are respectively connected to the feed distribution pipe.

[0026] Further preferably, the end of the internal feed main pipe extends into the center of the tank body and is evenly divided into two internal feed branch pipes on both sides, the ends of the two internal feed branch pipes are respectively connected to the feed distribution pipe, and the material injector is symmetrically arranged relative to the two internal feed branch pipes.

[0027] Alternatively, the end of the internal feed main pipe is connected downward to the top of the cylindrical liquid distribution box, one end of the internal feed branch pipe is respectively connected to the outer wall of the liquid distribution box, and the other end is respectively connected to the feed distribution pipe. The internal feed branch pipes are evenly and symmetrically distributed along the outer wall of the liquid distribution box.

[0028] The mixed material enters the liquid distribution box along the internal feed main pipe, and is evenly distributed to the feed distribution pipe through the internal feed branch pipe, and then is sprayed and reacted through the material injector.

[0029] Such an arrangement makes the distribution of the mixed feed in the tank body more uniform, and the subsequent injection reaction through the material injector is more uniform, the reaction conversion rate is improved, and the quality is improved.

[0030] Preferably, the methanol feed pipeline comprises a methanol feed main pipe and a methanol feed branch pipe, one end of the methanol feed branch pipe is connected to the methanol feed main pipe, and the other end is respectively connected to the external feed main pipe in front of the feed port.

[0031] It should be noted that, when N is an integer greater than 1, the other end of one of the methanol feed branch pipes is connected to the external feed main pipe to serve as methanol feed; the other end of the other methanol feed branch pipe is connected to the intermediate connecting pipeline to compensate methanol for the subsequent reaction tank;

[0032] The enzyme-catalyzed reaction device also includes a first methanol reflux pipeline and at least one second methanol reflux pipeline, one end of the first methanol reflux pipeline extends into the upper part of the reaction tank, a collecting funnel with an upward opening is installed at the end, and the other end merges with the methanol feed branch pipe; one end of the second methanol reflux pipeline extends into the middle part of the reaction tank, and the other end merges with the methanol feed branch pipe.

[0033] With such arrangement, the methanol layer on the upper part of the tank body can be better collected, and the unreacted materials in the middle part of the tank body can also be effectively circulated, which can effectively reduce methanol volatilization, improve methanol utilization rate, and improve conversion rate.

[0034] Preferably, the enzyme feed pipeline includes an enzyme feed main pipe and an enzyme supplement main pipe; a plurality of enzyme supplement branch pipes branch out from the enzyme supplement main pipe, the enzyme supplement branch pipes are connected to the supplement pipe port at the top of the tank body, and the bottom of the supplement pipe port is inserted into the tank body.

[0035] With such arrangement, when the enzyme content in the reaction tank is insufficient, the enzyme can be replenished promptly and quickly without adjusting the flow of the enzyme feed main pipe, thereby reducing the control difficulty and improving the control accuracy.

[0036] Preferably, the bottom of the supplementary pipe is inserted into the collecting funnel. This arrangement allows the supplemented enzyme to be pre-mixed with raw materials such as methanol before entering the reaction tank, effectively ensuring the reactivity of the enzyme and improving the conversion rate.

[0037] According to another preferred technical solution of the present invention, the enzyme catalytic reaction device for biodiesel further comprises a first static mixer, a second static mixer, a third static mixer and a plurality of heat exchangers;

[0038] The crude oil feed pipeline and the alkali solution feed pipeline are respectively connected to the feed port of the first static mixer, the enzyme feed pipeline and the water feed pipeline are respectively connected to the feed port of the second static mixer, the external feed main pipe is connected to the third static mixer, the discharge ports of the first static mixer and the second static mixer are respectively connected to the external feed main pipe in front of the third static mixer through pipelines, and the methanol feed pipeline is connected to a feed port of the third static mixer; a heat exchanger is also connected to the external feed main pipe before the feed port of the reaction tank, and a heat exchanger is arranged on the discharge pipeline between the separation equipment and the discharge pump.

[0039] Preferably, the outside of the reaction tank is respectively provided with a jacket, and the temperature of the medium in the jacket is controlled at 40±2°C.

[0040] The separation device can be a conventional device for separating glycerol from the product of biodiesel enzyme catalysis reaction in the prior art, such as a sedimentation tank, a centrifuge. Preferably, the separation device is a centrifuge.

[0041] The second object of the present invention is to provide an enzyme catalytic reaction method, using the above-mentioned biodiesel enzyme catalytic reaction device, the mixed raw material passes through N reaction tanks for continuous cyclic injection reaction, comprising the following steps:

[0042] The mixed raw material enters the internal feed main pipe and feed distribution pipe through the feed inlet of the reaction tank, and then passes through a plurality of material injectors evenly distributed along the inner wall of the tank body for cyclic injection reaction;

[0043] The temperature of the mixed raw material is controlled to be 40±2°C, and the reaction temperature in the reaction tank is controlled to be 40±2°C; the total reaction time T of the mixed raw material passing through the N reaction tanks is controlled to be 15 to 24 hours. Then the reaction time of each tank is T / N.

[0044] Preferably, the number of the material injectors installed in one reaction tank is 4 to 8.

[0045] The dimensions of the material injector are as follows: the maximum outer diameter D1 of the mixing section is 10 to 100 mm, the inner diameter D2 of the reduced diameter section is 10 to 50 mm, the maximum inner diameter D3 of the expanded section is 15 to 120 mm, the distance L1 from the starting end of the mixing section to the end of the expanded section is 100 to 300 mm, the length L2 of the mixing section is 10 to 100 mm, and the length L3 of the reduced diameter section is 10 to 100 mm.

[0046] The output pressure of the feed pump is 0.11-0.3 MPaG. The output pressure of the feed pump can be flexibly adjusted according to factors such as the pressure head loss of the pipeline, the head of the selected feed pump, and the height of the reaction tank.

[0047] Compared with the prior art, the present invention has the following beneficial technical effects:

[0048] The enzyme catalytic reaction device and reaction method of biodiesel of the present invention, wherein the mixed material passes through N reaction tanks and a plurality of material injectors evenly distributed along the inner wall of the tank body for cyclic injection reaction, can effectively realize the continuous reaction production of biodiesel. Compared with the stirring reaction adopted by the existing intermittent reactor, under the condition that the acid value of crude biodiesel is equivalent, the reaction time is significantly shortened, the production energy consumption is significantly reduced, and the daily output of biodiesel is significantly increased.

[0049] At the same time, since the present invention uses a material ejector to carry out a cyclic injection reaction instead of an intermittent stirring reaction, the volume of the reaction tank can be larger and the reaction capacity of the device is greater. Under the premise of the same crude oil processing volume, the equipment investment of the present invention is significantly less, the equipment operation difficulty is reduced, the inspection and maintenance are easy, and the operating cost is significantly reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a flow chart of the enzyme catalytic reaction device for biodiesel in Example 1.

[0051] Figure 2 This is a schematic diagram (sectional view) of the structure of the reaction tank of Example 1.

[0052] Figure 3 Schematic diagram of the distribution structure of the feed pipeline and material injector in the reaction tank.

[0053] Figure 4 It is a structural schematic diagram of the material ejector.

[0054] Figure 5 This is a schematic diagram of the distribution structure of the feed pipeline and material injector in the reaction tank of Example 2.

[0055] Figure 6 The figure is a flow chart of an existing enzymatic reaction device for biodiesel using intermittent kettle reactors (10 reactors, only 2 of which are shown in the figure).

[0056] Figure 7 This is a schematic diagram of the structure of the horizontal reactor used in the horizontal continuous reaction method.

[0057] In the figure:

[0058] 100-reaction tank, 200-raw oil feed pipeline, 300-alkali solution feed pipeline, 400-enzyme feed pipeline, 500-soft water feed pipeline, 600-1-first static mixer, 600-2-second static mixer, 600-3-third static mixer, 700-methanol feed main pipe, 800-enzyme supplement main pipe, 810-enzyme supplement branch pipe, 900-heat exchanger;

[0059] 110-first methanol reflux pipeline, 120-second methanol reflux pipeline, 111-collecting funnel, 710-methanol feed branch pipe;

[0060] 130-feeding port, 140-discharging port, 150-external feed main pipe, 160-intermediate connecting pipeline, 170-discharging pipeline, 180-discharging pump, 1000-centrifuge, 190-circulation main pipe, 1100-internal feed main pipe, 1110-internal feed branch pipe, 1120-feeding distribution pipe, 1130-material ejector, 151-feeding pump;

[0061] 1131 -feed connecting pipe, 1132 -mixing section, 1133 -reducing section, 1134 -enlarging section, 1135 -intake pipe opening, 1136 -convex head section. DETAILED DESCRIPTION

[0062] The following is a further detailed description of the enzymatic reaction device and reaction method of biodiesel of the present invention with reference to the accompanying drawings. It should be understood that the following embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0063] Example 1: Biodiesel enzyme catalytic reaction device

[0064] like Figures 1 to 4 As shown, the enzyme catalytic reaction device for biodiesel of this embodiment includes five reaction tanks 100 connected in sequence, a crude oil feed pipeline 200, an alkali solution feed pipeline 300, an enzyme feed pipeline 400, a soft water feed pipeline 500, a first static mixer 600-1, a second static mixer 600-2, a third static mixer 600-3, a methanol feed main pipe 700, a methanol feed branch pipe 710, a first methanol reflux pipeline 110, a second methanol reflux pipeline 120, an enzyme feed main pipe 410, an enzyme supplement main pipe 800, an enzyme supplement branch pipe 810 and six heat exchangers 900.

[0065] The reaction tank 100 includes a tank body, a feed port 130 and a discharge port 140 arranged at the lower part of the tank body; the feed port of the first reaction tank 100 is connected to the outside with an external feed main pipe 150, the crude oil feed pipeline 200 and the alkali solution feed pipeline 300 are respectively connected to the feed port of the first static mixer 600-1, the enzyme feed main pipe 410 and the soft water feed pipeline 500 are respectively connected to the feed port of the second static mixer 600-2, the external feed main pipe 150 is connected to the third static mixer 600-3, the first static mixer 600-1 and the second static mixer 600-2 The discharge port of the third static mixer 600-3 is connected to the external feed main pipe 150 in front of the third static mixer 600-3 through a pipeline, and the feed port of the third static mixer 600-3 is connected to the end of the methanol feed branch pipe 710; one end of the first methanol reflux pipeline 110 extends into the upper part of the reaction tank 100, and the other end merges with the methanol feed branch pipe 710, and one end of the second methanol reflux pipeline 120 extends into the middle part of the reaction tank 100, and the other end merges with the methanol feed branch pipe 710; the external feed main pipe 150 is also connected to a heat exchanger 900 before the feed port of the first reaction tank 100. A feed pump 151 is arranged on the external feed main pipe 150 after the heat exchanger 900.

[0066] The discharge port of the previous reaction tank 100 is connected to the feed port of the next reaction tank 100 through an intermediate connecting pipeline 160, and the intermediate connecting pipeline 160 is also connected to the methanol feed branch pipe 710; the discharge port of the last reaction tank 100 is connected to the discharge pipeline 170, and the discharge pipeline 170 is provided with a discharge pump 180 and connected to the centrifuge 1000; the discharge pipeline 170 after the discharge pump 180 is connected to a circulation main pipe 190, and the other end of the circulation main pipe 190 is connected to the external feed main pipe 150 before the heat exchanger 900; the discharge pipeline 170 between the centrifuge 1000 and the discharge pump 180 is provided with a heat exchanger 900. The intermediate connecting pipelines 160 before the feed ports of the subsequent reaction tanks 100 are respectively provided with heat exchangers 900.

[0067] The feed port of the reaction tank 100 is internally connected to an internal feed main pipe 1100, the end of the internal feed main pipe 1100 extends into the center of the tank body and is evenly divided into two internal feed branch pipes 1110 on both sides, the ends of the two internal feed branch pipes 1110 are respectively connected to an annular feed distribution pipe 1120; the feed distribution pipe 1120 is evenly connected with material injectors 1130.

[0068] The material injector 1130 is a Venturi-type injector, including a feed connecting pipe 1131, a mixing section 1132, a reduced diameter section 1133 connected to the mixing section 1132, an expanded section 1134 connected to the reduced diameter section 1133, and a spherical segment-shaped convex head section 1136 connected to the expanded section 1134, wherein a plurality of injection holes are provided on the convex head section 1136; one end of the feed connecting pipe 1131 is connected to the feed distribution pipe 1120, and the other end extends into the mixing section 1132, wherein the mixing section 1132 is provided with a suction pipe port 1135.

[0069] The mixed material enters the mixing section 1132 through the feed connecting pipe 1131, then enters the expanding section 1134 through the reducing section 1133, and finally enters the convex section 1136, and is sprayed out to all sides from the spray hole of the convex section 1136. The spray angle and direction are large, and the spray reaction of the mixed material in the reactor is more uniform.

[0070] like Figure 2 As shown, the injection trajectory of the mixed material after being injected from the convex head section 1136 of the material injector 1130 is spherical. This arrangement makes the injection reaction of the mixed material in the reaction tank 100 more uniform and rapid, and the reaction conversion rate is increased.

[0071] The reaction tanks 100 are respectively provided with jackets, the medium in the jackets is water, and the temperature of the water is controlled at 40±2°C.

[0072] The first methanol reflux pipeline 110 extends into the upper end of the reaction tank 100 and is provided with a collecting funnel 111 with its opening facing upward; four enzyme supplement branch pipes 810 branch out from the enzyme supplement main pipe 800, and the four enzyme supplement branch pipes 810 are respectively inserted into the collecting funnels 111 in the first to fourth reaction tanks.

[0073] Since the reaction time of the material in the last reaction tank 100 is relatively short, the addition of enzyme has little effect on improving the reaction conversion rate. Therefore, the enzyme addition branch pipe may not be provided.

[0074] The enzyme catalytic reaction device for biodiesel of the present invention adopts the following reaction method:

[0075] (1) The crude oil and alkali solution are mixed through the first static mixer 600-1 to obtain a crude oil feed with a pH of 5.0 to 6.0; the enzyme and soft water are mixed through the second static mixer 600-2 to obtain an enzyme feed; then the crude oil feed, enzyme feed and methanol feed are mixed together through the third static mixer 600-3, and then heat exchanged to 40±2°C through the heat exchanger 900 to obtain a mixed feed, which then enters the first reaction tank 100.

[0076] (2) The mixed feed passes through the internal feed main pipe 1100, then enters the annular feed distribution pipe 1120 along the internal feed branch pipe 1110, and finally passes through the material injector 1130 for cyclic injection reaction. The material flowing out of the discharge port of the first reaction tank 100 enters the feed port of the next reaction tank 100 through the intermediate connecting pipeline 160, and the injection reaction is repeated; the material flowing out of the discharge port of the last reaction tank 100 enters the centrifuge 1000 through the discharge pipeline for centrifugal separation to obtain crude biodiesel with an acid value of 4 to 6 mg KOH / g.

[0077] At the same time, the methanol-containing clear liquid layer in the upper part of the first reaction tank 100 and the incompletely reacted materials in the middle part are respectively extracted through the first methanol reflux pipeline 110 and the second methanol reflux pipeline 120, and merged into the methanol feed branch pipe 710 for circulation reaction.

[0078] It should be noted that a sampling pipeline is provided on the discharge pipeline of the last reactor 100, which is used to detect and analyze the acid value of the crude biodiesel obtained after the reaction of the last reactor. If the conversion rate meets the standard, the crude biodiesel is directly transported to the centrifuge through the discharge pump for centrifugal separation, and finally obtains biodiesel with an acid value of 4 to 6 mg KOH / g. A methanol solution of potassium hydroxide is added to the biodiesel with an acid value of 4 to 6 mg KOH / g to adjust the acid value to within 0.5 mg KOH / g, and the final product biodiesel is obtained. If the conversion rate does not meet the standard (acid value>6 mg KOH / g), the crude biodiesel that does not meet the standard is circulated back to the external feed main pipe 150 before the heat exchanger 900 along the circulation main pipe 190, or circulated back to the intermediate connecting pipe 160 before the heat exchanger 900, so that the material continues to react.

[0079] The specific reactor to which the crude biodiesel that does not meet the standards is recycled is determined by the acid value of the crude biodiesel. If the acid value is greater than the acid value of the mixed material at the outlet of the first reactor, it is recycled to the first reactor. If the acid value is greater than the acid value of the mixed material at the outlet of the second reactor, it is recycled to the second reactor, and so on.

[0080] Preferably, in the orthographic projection view, the angle between the axis centerline of the material ejector 1130 and the horizontal plane is 30 to 80 degrees, more preferably 30 to 60 degrees.

[0081] Preferably, there are 4 to 8 material injectors 1130, which are evenly distributed along the annular feed distribution pipe 1120 and are symmetrically arranged relative to the two internal feed branches.

[0082] It should be noted that the volume and number of the reaction tank can be flexibly adjusted according to the output of biodiesel. The number of the material injectors can be flexibly adjusted according to the volume of the reaction tank and the injection flow rate of the material injectors, the feed of the pump and other parameters.

[0083] Example 2: Biodiesel enzyme catalytic reaction device

[0084] like Figure 5 As shown, the basic process and structure are the same as those of Example 1, except that the connection method between the internal feed main pipe 1100 at the bottom of the reaction tank and the annular feed distribution pipe 1120 is different. Specifically:

[0085] The end of the internal feed main pipe 1100 is connected downward to the top of the cylindrical liquid distribution box 1140, one end of the internal feed branch pipe 1110 is respectively connected to the outer wall of the liquid distribution box 1140, and the other end is respectively connected to the feed distribution pipe 1120. The internal feed branch pipes 1110 are evenly and symmetrically distributed along the outer wall of the liquid distribution box 1140.

[0086] The mixed material enters the liquid distribution box 1140 at a certain pressure and flow rate along the internal feed main pipe 1100, and is evenly distributed to the feed distribution pipe 1120 through the internal feed branch pipe 1110 again, and then undergoes a cyclic injection reaction through the material injector 1130. With this arrangement, the distribution of the mixed material is more uniform, which is conducive to improving the cyclic injection reaction efficiency of the material.

[0087] Comparative Example 1: Intermittent enzyme catalytic reaction device for biodiesel

[0088] like Figure 6 As shown, a conventional intermittent kettle reactor is used, the crude oil and alkali solution are mixed through the fourth static mixer 600-4 to obtain the crude oil feed; the enzyme and soft water are mixed to obtain the enzyme feed; the crude oil feed, the enzyme feed and the methanol feed enter the intermittent kettle reactor, the upper methanol-containing clear liquid layer is circulated through the methanol circulation pipeline, and reacts to an acid value of 4 to 6 mg KOH / g under the stirring action of the stirrer to obtain a reaction mass. Then the reaction mass is centrifuged in the centrifuge to obtain crude biodiesel.

[0089] Example 3, pilot reaction

[0090] Five reaction tanks were used for continuous reaction. The diameter of the reaction tanks was 1.0 m, the height was 2.0 m, and the total volume was 1.57 m 3 Combined with the actual effective volume of the spray reactor (filling rate 85%), the amount of mixed feed that can be loaded into one reactor is usually 1.20 tons, of which the feed amount of crude oil is 1.0 ton and the feed amount of methanol is 0.20 ton. Then, 5 reactors can be loaded with 5 tons of crude oil.

[0091] Raw oil properties: pre-treated kitchen waste oil, temperature 50-70°C, slightly acidic (pH 4.0-5.0), acid value: <100 mg KOH / g, moisture: 0.2-0.5%.

[0092] Reaction conditions: pH 5.0-6.0; water dosage: 2% of the raw oil content (including the water content of the raw oil itself); enzyme dosage: 0.2% of the raw oil content; reaction temperature: 40±2° C. There are three material injectors, which are evenly distributed, and the angle between the material injectors and the horizontal plane is 30-85 degrees.

[0093] The dimensions of the material ejector are: D1 40mm, D2 20mm, D3 42mm, L1 100mm, L2 30mm, L3 30mm. The diameter of the feed connection pipe 1131 is 30mm, and the diameter of the suction pipe port 1135 is 30mm. The output pressure of the feed pump is 0.13MPaG.

[0094] The feed connection pipe 1131 is connected to the feed distribution pipe 1120 through a tee, and the angle of the material injector 1130 can be adjusted by adjusting the installation angle of the tee and the feed distribution pipe 1120. It is easy for those skilled in the art to understand that the feed distribution pipe 1120 connected to the tee line is a straight pipe.

[0095] When the device is started, when the first reaction tank is not full, the discharge valve installed on the discharge port is in a closed state. When the continuous feeding time is T / 5 and the reaction tank is full, the discharge valve installed on the discharge port can be opened to allow the partially reacted material in the first reaction tank to continuously enter the second reaction tank. And so on. When all five reaction tanks are full and the reaction time reaches T, the discharge valve of the fifth reaction tank is opened to discharge continuously. At the same time, the first reaction tank continues to feed continuously to achieve continuous reaction.

[0096] Therefore, in order to improve the accuracy of the comparative data, the devices of Example 1 and Example 2 respectively adjusted the material injector 1130 to different angles, and operated them for 10 days respectively. After the operation stabilized, the average data of 3 consecutive days was taken, and the standard of the prepared biodiesel was calculated as shown in Table 1.

[0097] Table 1 Comparison of enzyme catalytic reaction parameters and acid values ​​in the examples

[0098]

[0099]

[0100] From the data in Table 1, it can be seen that the enzyme catalytic reaction device of Example 1 and Example 2 is used for enzyme catalytic reaction, and the reaction time is 15 to 24 hours to achieve an acid value of 4.3 to 5.3 mg KOH / g, reaching the range of 4 to 6 mg KOH / g. Therefore, the enzyme catalytic reaction device of Example 1 and Example 2 is a continuous reaction device with high reaction efficiency.

[0101] In practical applications, under the conditions of certain size, installation angle and number of material ejectors, the reaction time of a single reaction tank can be ensured to be within the range of 15 to 24 hours by adjusting the feed flow rate of the feed pump and the discharge flow rate of the discharge pump. The output pressure head of the pump is used to ensure that the mixed material can be ejected from the feed connection pipe 1131 at high speed, and a negative pressure is formed at the mixing section 1132, so that the mixed material in the reaction tank is sucked from the suction pipe port 1135, mixed at high speed through the reduced diameter section 1133, further mixed through the expanded section 1134, and finally ejected from the mesh of the screen protrusion 1136 to the surroundings.

[0102] The material ejector can effectively cycle and eject the mixed material in the reaction tank 10 under the output pressure of the feed pump, just like a high-pressure water gun ensures that water can be ejected at high speed from a nozzle installed at the end of the high-pressure water gun through the output pressure of the compressor.

[0103] Application Examples

[0104] The enzyme catalytic reaction device of Comparative Example 1 and Example 1 was used for industrial preparation of biodiesel, using the same enzyme.

[0105] Raw oil properties: pre-treated kitchen waste oil, temperature 50-70°C, slightly acidic (pH 4.0-5.0), acid value: <100 mg KOH / g, moisture: 0.2-0.5%.

[0106] Reaction conditions: pH 5.0-6.0; water dosage: 2% of the raw oil content (including the water content of the raw oil itself); enzyme dosage: 0.2% of the raw oil content; reaction temperature: 40±2°C.

[0107] In Example 1, 5 reaction tanks were designed, each with a diameter of 3.2 m, a height of 6.0 m, and a total volume of 48 m 3 Combined with the actual effective volume of the spray reactor (filling rate 85%), the amount of mixed feed that can be loaded into one reactor is usually 36 tons, of which the feed amount of crude oil is 30 tons and the feed amount of methanol is 6 tons. Then, 5 reactors can be loaded with 150 tons of crude oil.

[0108] There are 8 material injectors. Figure 2As shown, the angle between the material ejector and the horizontal plane is 45 degrees. The dimensions of the material ejector are: D1 60mm, D2 30mm, D3 63mm, L1 150mm, L2 45mm, L3 45mm. The diameter of the feed connection pipe 1131 is 45mm, and the diameter of the suction pipe port 1135 is 45mm. The output pressure of the feed pump is 0.2MPaG.

[0109] It is easy for a person skilled in the art to understand that the feed flow rate can be adjusted according to parameters such as the reaction time of the mixed material in a single reaction tank (approximately the residence time of the material) and the output pressure head of the feed pump.

[0110] Due to the limitation of the stirring performance of the stirred tank reactor, the volume of the stirred tank reactor cannot be too large. Therefore, in Comparative Example 1, 10 reaction tanks were designed, with a diameter of 2.5 m, a height of 5 m, and a volume of 24.5 m 3 . Combined with the actual effective volume of the intermittent reaction tank (filling rate 82%), the amount of mixed feed that can be filled in a reaction tank is usually 18 tons. The feed of crude oil is 15 tons, and the feed of methanol is 3 tons. 10 reaction tanks can hold 150 tons of crude oil and 30 tons of methanol. In the intermittent reaction, the feeding time of a batch of materials is about 2 hours, and the discharging time is 2 hours, so the intermediate operation time of a batch of materials is 4 hours.

[0111] When the device is started, when the first reaction tank is not full, the discharge valve installed on the discharge port is in a closed state. When the continuous feeding time is T / 5 and the reaction tank is full, the discharge valve installed on the discharge port can be opened to allow the partially reacted material in the first reaction tank to continuously enter the second reaction tank. And so on. When all five reaction tanks are full and the reaction time reaches T, the discharge valve of the fifth reaction tank is opened to discharge continuously. At the same time, the first reaction tank continues to feed continuously to achieve continuous reaction.

[0112] Therefore, in order to improve the accuracy of the comparative data, the device of Example 1 was operated for 10 days, and the average data of 3 consecutive days was taken after the operation stabilized. The standard of the prepared biodiesel was calculated as shown in Table 2.

[0113] Table 2 Comparison of enzyme catalytic reaction parameters and acid values ​​between Comparative Example 1 and Example 1

[0114]

[0115] It can be seen from the data in Table 2 that, for the same reaction of biodiesel to an acid value in the range of 4 to 6 mg KOH / g, the reaction time of the enzyme-catalyzed reaction device for biodiesel of the present invention is 15 to 24 hours, which is significantly lower than the reaction time of the existing intermittent reactor. Therefore, the overall reaction energy consumption is significantly reduced, the production cost is significantly reduced, and the acid value of the crude biodiesel obtained by the present invention is significantly lower, in the range of 4.2 to 5.1 mg KOH / g.

[0116] At the same time, the present invention adopts a continuous reaction method, the volume of the reaction tank is larger, and the number of reaction tanks and control devices installed on the reaction tanks required under the same daily production conditions is reduced, so the control efficiency is high and the control accuracy is better. When the feed flow rate is increased, not only the total reaction time is significantly shortened, but also the daily production of biodiesel is significantly increased. According to the data recorded in Table 2, the daily production can be increased by 20-60%.

[0117] The specific embodiments of the present invention are described in detail above, but they are only examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modification and substitution of the practical is also within the scope of the present invention. Therefore, the equalization transformation and modification made without departing from the spirit and scope of the present invention should be included in the scope of the present invention.

Claims

1. An enzyme catalytic reaction device for biodiesel, characterized in that: The method comprises N reaction tanks, a crude oil feed pipeline, an alkali solution feed pipeline, an enzyme feed pipeline, a water feed pipeline and a methanol feed pipeline connected in sequence, wherein N is an integer greater than 1; wherein: The reaction tank comprises a tank body, a feed port and a discharge port arranged on the tank body; the outside of the feed port of the first reaction tank is connected to an external feed main pipe, and a feed pump is arranged on the external feed main pipe; the inside of the feed port of the reaction tank is connected to an internal feed main pipe, and the internal feed main pipe is connected to a feed distribution pipe, and a plurality of material injectors are connected through the feed distribution pipe, and the plurality of material injectors are evenly distributed in an annular manner along the inner wall of the tank body; the material injectors are arranged obliquely, and the nozzle outlet faces upward; The feeds from the crude oil feed pipeline, the alkali solution feed pipeline, the enzyme feed pipeline, the water feed pipeline and the methanol feed pipeline are mixed to obtain a mixed material, the mixed material continuously enters the tank body through the external feed main pipe, and is subjected to a cyclic injection reaction through the material injector; The discharge port of the last reaction tank is connected to the discharge pipeline, and a discharge pump is arranged on the discharge pipeline and connected to the separation device; the discharge pipeline after the discharge pump is connected to a circulation main pipe, and the discharge port of the previous reaction tank is connected to the feed port of the next reaction tank through an intermediate connecting pipeline; the other end of the circulation main pipe is connected to the external feed main pipe and / or the intermediate connecting pipeline; The feed distribution pipe is an annular distribution pipe arranged along the inner wall of the tank body; the end of the internal feed main pipe extends into the center of the tank body and is connected to the internal feed branch pipe, and the ends of the internal feed branch pipes are respectively connected to the feed distribution pipe; The methanol feed pipeline comprises a methanol feed main pipe and a methanol feed branch pipe, one end of the methanol feed branch pipe is connected to the methanol feed main pipe, and the other end is respectively connected to the external feed main pipe in front of the feed port; The enzyme catalytic reaction device also includes a first methanol reflux pipeline and at least one second methanol reflux pipeline, one end of the first methanol reflux pipeline extends into the upper part of the reaction tank, a collecting funnel with an opening facing upward is installed at the end, and the other end merges with the methanol feed branch pipe; one end of the second methanol reflux pipeline extends into the middle part of the reaction tank, and the other end merges with the methanol feed branch pipe; The enzyme feeding pipeline includes an enzyme feeding main pipe and an enzyme supplement main pipe; a plurality of enzyme supplement branch pipes are branched from the enzyme supplement main pipe, the enzyme supplement branch pipes are connected to the supplement pipe port at the top of the tank body, the bottom of the supplement pipe port is inserted into the tank body; the bottom of the supplement pipe port is inserted into the collecting funnel.

2. The enzyme catalytic reaction device for biodiesel according to claim 1, characterized in that: The material injector is a Venturi-type injector, comprising a feed connection pipe, a mixing section, a reduced diameter section connected to the mixing section, an enlarged section connected to the reduced diameter section, and a convex head section connected to the enlarged section, wherein a plurality of injection holes are provided on the convex head section; One end of the feed connecting pipe is connected to the feed distribution pipe, and the other end extends into the mixing section. The mixing section is provided with a suction pipe opening.

3. The enzyme catalytic reaction device for biodiesel according to claim 1, characterized in that: The angle between the axis center line of the material ejector and the horizontal plane is 30 to 85 degrees.

4. The enzymatic reaction device for biodiesel according to any one of claims 1 to 3, characterized in that: Also includes a first static mixer, a second static mixer, a third static mixer and a plurality of heat exchangers; The crude oil feed pipeline and the alkali solution feed pipeline are respectively connected to the feed port of the first static mixer, the enzyme feed pipeline and the water feed pipeline are respectively connected to the feed port of the second static mixer, the external feed main pipe is connected to the third static mixer, the discharge ports of the first static mixer and the second static mixer are respectively connected to the external feed main pipe in front of the third static mixer through pipelines, and the methanol feed pipeline is connected to a feed port of the third static mixer; a heat exchanger is also connected to the external feed main pipe before the feed port of the reaction tank, and a heat exchanger is arranged on the discharge pipeline between the separation equipment and the discharge pump.

5. An enzyme-catalyzed reaction method, characterized in that: The enzymatic reaction device for biodiesel according to any one of claims 1 to 4 is used, wherein the mixed material is continuously sprayed through N reaction tanks, comprising the following steps: The mixed material enters the internal feed main pipe and the feed distribution pipe through the feed inlet of the reaction tank, and then passes through a plurality of material injectors evenly distributed along the inner wall of the tank body for cyclic injection reaction; Control the temperature of the mixed material to 40±2°C, and control the reaction temperature in the reaction tank to 40±2°C; The total reaction time T of the mixed material passing through the N reaction tanks is controlled to be 15 to 24 hours.

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