Method for reducing acid value and peroxide value of grease based on microchannel reactor

Abstract

The invention belongs to the technical field of microchannels, and particularly relates to a method for reducing the acid value and peroxide value of grease based on a microchannel reactor, which comprises the following steps: S1, preparing a sodium hydroxide solution and grease, and controlling the temperature range to be 40-65 DEG C; s2, the sodium hydroxide solution and grease are conveyed into a micro-mixer to be subjected to a mixed reaction and flow into a first micro-channel to continue the reaction, the micro-mixer is placed in a water bath environment at the temperature of 40-70 DEG C, the first micro-channel comprises a front section placed in the water bath environment at the temperature of 40-75 DEG C and a rear section placed in the water bath environment at the temperature of 60-80 DEG C, and a mixed solution is obtained; s3, collecting a mixed solution at an outlet of the first micro-channel, and centrifuging to remove saponified substances and water to obtain deacidified grease; s4, the deacidified grease is conveyed into a second micro-channel, the second micro-channel comprises a front section placed in an oil bath environment of 150-250 DEG C and a rear section placed in a water bath environment of 60 DEG C or below, and refined grease is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of microchannels, and in particular relates to a method for reducing the acid value and peroxide value of oil based on a microchannel reactor. Background Art

[0002] With the advancement of science and technology, microchemical technology has gradually emerged and become the new favorite in the chemical industry. As the core equipment of microchemical technology, microchannel reactors have been widely used in the field of chemical synthesis due to their efficient mass and heat transfer performance, precise temperature and pressure control, and continuous flow reaction characteristics. The micro-cavity array structure inside the microchannel reactor allows the materials to be fully mixed inside the reactor, greatly improving the reaction efficiency. At the same time, the microchannel reactor has high heat and mass transfer efficiency and can quickly transfer the heat generated by the reaction to avoid local overheating. In addition, microchannel reactors also have the advantages of continuous operation, easy scale-up, and easy integration, which has brought revolutionary changes to chemical production.

[0003] Although microchannel reactors have made remarkable achievements in the field of chemical synthesis, their application in the field of oil refining is relatively rare. Although there have been attempts, the continuity is poor, and the acid value and peroxide value of oils and fats cannot be completed continuously. Traditional oil refining methods still dominate, resulting in problems such as low oil refining efficiency.

[0004] Therefore, how to overcome the defect that the microchannel reactor cannot continuously reduce the acid value and peroxide value of oil is a technical problem that urgently needs to be solved in this field.

[0005] Therefore, the present invention proposes a method for oil refining using a microchannel reactor to solve the problems existing in traditional oil refining methods and promote the innovation and development of oil refining technology.

[0006] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0007] The embodiments of the present disclosure at least provide a method for reducing the acid value and peroxide value of oil based on a microchannel reactor.

[0008] In the first aspect, an embodiment of the present disclosure provides a method for reducing the acid value and peroxide value of oil based on a microchannel reactor, comprising the following steps: step S1, preparing sodium hydroxide solution and oil, and controlling the temperature range at 40-65°C; step S2, conveying the sodium hydroxide solution and oil to a micromixer for mixed reaction, and flowing into a first microchannel to continue the reaction, wherein the micromixer is placed in a 40-70°C water bath environment, and the first microchannel includes a front section placed in a 40-75°C water bath environment and a rear section placed in a 60-80°C water bath environment to obtain a mixed liquid; step S3, collecting the mixed liquid at the outlet of the first microchannel, centrifuging to remove saponification and water, and obtaining deacidified oil; step S4, conveying the deacidified oil to a second microchannel, wherein the second microchannel includes a front section placed in a 150-250°C oil bath environment and a rear section placed in a water bath environment below 60°C, to obtain refined oil.

[0009] In an optional embodiment, the micromixer is any one of a T-type micromixer, a Y-type micromixer, a coaxial micromixer, and an interdigital micromixer.

[0010] In an optional embodiment, the oil includes any one or more combinations of snake oil, lard, mutton fat, beef tallow, soybean oil, rapeseed oil, olive oil, and peanut oil.

[0011] In an optional embodiment, the material of the first microchannel is any one of polytetrafluoroethylene, polyperfluoroethylene propylene, polypropylene, and stainless steel; the material of the second microchannel includes stainless steel.

[0012] In an optional embodiment, the diameter of the first microchannel is 0.3-10 mm; the diameter of the second microchannel is 0.3-10 mm.

[0013] In an optional embodiment, the first microchannel has a front-end reaction time of 5-50 s and a back-end reaction time of 5-50 s.

[0014] In an optional embodiment, the mass ratio of the sodium hydroxide solution to the oil is 1:

[0015] (5-25).

[0016] In an optional embodiment, the front-end reaction time of the second microchannel is 5-500s.

[0017] In an optional embodiment, the centrifugal speed in step S3 is 5000-20000 rpm, and the centrifugal time is 5-30 min.

[0018] In a second aspect, the embodiments of the present disclosure also provide a refined oil, which uses the above-mentioned method to reduce the oil acid value and peroxide value of the refined oil.

[0019] The beneficial effect of the present invention is that the method for reducing the acid value and peroxide value of oil based on the microchannel reactor makes the alkali solution and oil quickly and evenly mix and react in the microchannel by means of gradient temperature increase, thereby preventing the problem of excessive saponification of oil. The saponification reaction is an exothermic reaction, and the higher the temperature, the faster the reaction rate. At low temperatures, oil and alkali solution can be quickly and fully mixed, while the saponification reaction is slow. As the temperature increases, the reaction rate gradually increases, and the uniform mixing of alkali solution and oil greatly reduces the non-uniformity of the reaction and reduces local excessive saponification. In addition, the high heat transfer characteristics of the microchannel enable the heat released by the reaction to be transferred in time, avoiding the violent reaction caused by high temperature, and further reducing excessive saponification; at the same time, because the reaction yield in the first microchannel is high, it is only necessary to centrifuge to remove the saponified product to directly carry out the peroxide value reduction treatment. Based on the fact that the oil in the microchannel is not affected by air, high-quality refined oil can be obtained by rapid temperature increase and decomposition and then rapid cooling.

[0020] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description.

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below for detailed description as follows. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the following will be described clearly and completely in combination with the technical solution of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] As used herein, the phrases "in one embodiment," "according to one embodiment," "in some embodiments," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like are used to "serve as an example, instance, or illustration." Any implementation, aspect, or design described herein as "example" or "exemplary" is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0024] In this document, as used herein, expressions such as "at least one of..." when following a list of elements modify the entire list of elements rather than modifying the individual elements in the list. For example, the expression "at least one of a, b, and c" should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0025] The terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components and / or combinations thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0026] Traditionally, the acid value and peroxide value of oils and fats are reduced separately in the reactor. During the acid value reduction process, the alkali solution and the oil cannot be quickly and evenly mixed, which can easily cause excessive saponification of the oil and fat, reducing the yield. During the peroxide value reduction process, the oil and fat are heated to 200°C. In order to prevent the oil and fat from oxidizing at high temperatures, the reactor needs to be vacuumed.

[0027] The defects existing in the above solutions are the results obtained by the inventor after practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the present disclosure for the above problems below should be the contributions made by the inventor to the present disclosure during the disclosure process.

[0028] Some embodiments of the present invention are described in detail below. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] The disclosed embodiment provides a method for reducing the acid value and peroxide value of oil based on a microchannel reactor, comprising the following steps: step S1, preparing sodium hydroxide solution and oil, and controlling the temperature range to be 40-65°C; step S2, conveying the sodium hydroxide solution and oil to a micromixer for mixed reaction, and flowing into a first microchannel for continued reaction, wherein the micromixer is placed in a 40-70°C water bath environment, and the first microchannel includes a front section placed in a 40-75°C water bath environment and a rear section placed in a 60-80°C water bath environment, to obtain a mixed solution; step S3, collecting the mixed solution at the outlet of the first microchannel, centrifuging to remove saponification and water, to obtain deacidified oil; step S4, conveying the deacidified oil to a second microchannel, wherein the second microchannel includes a front section placed in a 150-250°C oil bath environment and a rear section placed in a water bath environment below 60°C, to obtain refined oil.

[0030] In some embodiments, specifically, the micromixer is any one of a T-type micromixer, a Y-type micromixer, a coaxial micromixer, and an interdigital micromixer.

[0031] In some embodiments, specifically, the oil includes any one or more combinations of snake oil, lard, mutton fat, beef tallow, soybean oil, rapeseed oil, olive oil, and peanut oil.

[0032] In some embodiments, specifically, the material of the first microchannel is any one of polytetrafluoroethylene, polyperfluoroethylene propylene, polypropylene, and stainless steel; the material of the second microchannel includes stainless steel.

[0033] In some embodiments, specifically, the diameter of the first microchannel is 0.3-10 mm; the diameter of the second microchannel is 0.3-10 mm.

[0034] In some embodiments, specifically, the first microchannel has a front-end reaction time of 5-50 s and a back-end reaction time of 5-50 s.

[0035] In some embodiments, specifically, the mass ratio of the sodium hydroxide solution to the oil is 1:(5-25).

[0036] In some embodiments, specifically, the front-end reaction time of the second microchannel is 5-500s.

[0037] In some embodiments, specifically, the centrifugal speed in step S3 is 5000-20000 rpm, and the centrifugal time is 5-30 min.

[0038] The disclosed embodiments also provide a refined oil, which uses the above-mentioned method to reduce the oil acid value and peroxide value of the refined oil.

[0039] The original snake oil was refined. The acid value of the original snake oil used in the embodiment was 16.62 mg KOH / g, and the peroxide value was 11.42 mmol / Kg.

[0040] Example 1

[0041] Snake oil heated to 50°C and 16% sodium hydroxide solution at 50°C are transported to a cross-finger micro-mixer, where the oil and sodium hydroxide are mixed and reacted, and then flow into a polytetrafluoroethylene tube with an inner diameter of 1 mm to continue the reaction.

[0042] The micromixer was placed in a 50°C water bath, the front section of the polytetrafluoroethylene microchannel was placed in a 60°C water bath, and the rear section of the microchannel was placed in a 70°C water bath. The mixed solution reacted in the front section and the rear section of the microchannel for 10 seconds respectively. The mixed solution was collected at the outlet of the pipeline, centrifuged at 8000rpm for 5 minutes to remove the saponification product and water, and the deacidified oil was obtained. The acid value was detected and the yield was calculated.

[0043] The snake oil heated to 60°C was transported to a stainless steel microchannel with an inner diameter of 1 mm. The oil bath temperature was 170°C. The oil stayed in the front section for 120 s. After cooling in the back section, the oil was collected and the peroxide value was tested.

[0044] Example 2

[0045] Snake oil heated to 45°C and a 16% sodium hydroxide solution at 45°C are transported to a cross-finger micro-mixer, where the oil and sodium hydroxide are mixed and reacted, and then flow into a polytetrafluoroethylene tube with an inner diameter of 1 mm to continue the reaction. The micro-mixer is placed in a 45°C water bath, the front section of the polytetrafluoroethylene microchannel is placed in a 65°C water bath, and the rear section of the microchannel is placed in an 80°C water bath. The mixed solution reacts in the front section and the rear section for 10 seconds respectively, and the mixed solution is collected at the outlet of the pipeline. After centrifugation at 8000rpm for 5 minutes, the saponified matter and water are removed to obtain the deacidified oil, and its acid value is detected and the yield is calculated.

[0046] The snake oil heated to 60°C was transported to a stainless steel microchannel with an inner diameter of 1 mm. The oil bath temperature was 195°C. The oil stayed in the front section for 120 s. After cooling in the back section, the oil was collected and the peroxide value was tested.

[0047] Example 3

[0048] Snake oil heated to 65°C and sodium hydroxide solution at 65°C were transported to a cross-finger micro-mixer, where the oil and sodium hydroxide were mixed and reacted, and then flowed into a polytetrafluoroethylene tube with an inner diameter of 1 mm to continue the reaction. The micro-mixer and the front and rear sections of the polytetrafluoroethylene microchannel were placed in a 70°C water bath, and the mixed solution reacted in the front and rear sections of the microchannel for 20 seconds each. The mixed solution was collected at the outlet of the pipeline, centrifuged at 8000rpm for 5 minutes to remove saponification and water, and the deacidified oil was obtained. Its acid value was tested and the yield was calculated.

[0049] The snake oil heated to 60°C was transported to a stainless steel microchannel with an inner diameter of 1 mm. The oil bath temperature was 230°C. The oil stayed in the front section for 120 s. After cooling in the back section, the oil was collected and the peroxide value was tested.

[0050] Example 4

[0051] Snake oil heated to 45°C and a 16% sodium hydroxide solution at 45°C are transported to a T-type micromixer, the oil and sodium hydroxide are mixed and reacted in the micromixer, and then flow into a stainless steel tube with an inner diameter of 1 mm to continue reacting. The micromixer is placed in a 45°C water bath, the front section of the polytetrafluoroethylene microchannel is placed in a 55°C water bath, and the rear section of the microchannel is placed in a 70°C water bath. The mixed solution reacts in the front section and the rear section of the microchannel for 20s and 10s respectively, the mixed solution is collected at the outlet of the pipeline, and the saponified matter and water are removed after centrifugation at 8000rpm for 5min to obtain deacidified oil, the acid value of which is detected, and the yield is calculated.

[0052] The snake oil heated to 60°C was transported to a stainless steel pipe with an inner diameter of 1 mm. The oil bath temperature was 230°C. The oil stayed in the front section of the microchannel for 60 s. After cooling in the rear section, the oil was collected and the peroxide value was tested.

[0053] Example 5

[0054] Snake oil at 50°C and a sodium hydroxide solution at 50°C with a concentration of 16% are transported to a cross-finger micromixer, the oil and sodium hydroxide are mixed and reacted in the micromixer, and then flow into a polytetrafluoroethylene microchannel with an inner diameter of 2 mm to continue reacting. The micromixer is placed in a 50°C water bath, the front section of the polytetrafluoroethylene microchannel is placed in a 60°C water bath, and the rear section of the microchannel is placed in a 70°C water bath. The mixed solution reacts in the front section and the rear section of the microchannel for 20 seconds respectively, the mixed solution is collected at the pipeline outlet, and the saponified matter and water are removed after centrifugation at 8000rpm for 5 minutes to obtain deacidified oil, the acid value of which is detected, and the yield is calculated.

[0055] The snake oil heated to 60°C was transported to a stainless steel pipe with an inner diameter of 1 mm. The oil bath temperature was 230°C. The oil stayed in the front section of the microchannel for 160 s. After cooling in the rear section, the oil was collected and the peroxide value was tested.

[0056] Example 6

[0057] Snake oil at 50°C and a sodium hydroxide solution at 50°C with a concentration of 16% are transported to a cross-finger micromixer, the oil and sodium hydroxide are mixed and reacted in the micromixer, and then flow into a polytetrafluoroethylene microchannel with an inner diameter of 3 mm to continue reacting. The micromixer is placed in a 50°C water bath, the front section of the polytetrafluoroethylene microchannel is placed in a 60°C water bath, and the rear section of the microchannel is placed in a 70°C water bath. The mixed solution reacts in the front section and the rear section of the microchannel for 20 seconds respectively, the mixed solution is collected at the pipeline outlet, and the saponified matter and water are removed after centrifugation at 8000rpm for 5 minutes to obtain deacidified oil, the acid value of which is detected, and the yield is calculated.

[0058] The snake oil heated to 60°C was transported to a stainless steel pipe with an inner diameter of 2 mm. The oil bath temperature was 230°C. The oil stayed in the front section of the microchannel for 180 s. After cooling in the rear section, the oil was collected and the peroxide value was tested.

[0059] Example 7

[0060] Snake oil at 50°C and a sodium hydroxide solution at 50°C with a concentration of 16% are transported to a cross-finger micromixer, where the oil and sodium hydroxide are mixed and reacted, and then flow into a polytetrafluoroethylene microchannel with an inner diameter of 5 mm to continue reacting. The micromixer is placed in a 50°C water bath, the front section of the polytetrafluoroethylene microchannel is placed in a 60°C water bath, and the rear section of the microchannel is placed in a 70°C water bath. The mixed solution reacts in the front section and the rear section of the microchannel for 20 seconds respectively, and the mixed solution is collected at the outlet of the pipeline. After centrifugation at 8000rpm for 5 minutes, saponification and water are removed to obtain deacidified oil, the acid value of which is detected, and the yield is calculated.

[0061] The snake oil heated to 60°C was transported to a stainless steel pipe with an inner diameter of 4 mm. The oil bath temperature was 230°C. The oil stayed in the front section of the channel for 180 s. After cooling in the rear section, the oil was collected and the peroxide value was tested.

[0062] Specifically, the acid value and peroxide value of the oils and fats of Examples 1-7 after treatment are shown in Table 1 below.

[0063] Table 1 Acid value and peroxide value of Examples 1-7

[0064] Example Acid value (mgKOH / g) Yield (%) Peroxide value (mmol / Kg) Snake oil as is 16.62 - 11.42 Example 1 0.16 88.75 6.86 Example 2 0.17 84.38 3.88 Example 3 0.22 82.23 0.90 Example 4 0.21 87.41 2.15 Example 5 0.23 79.73 0.87 Example 6 0.46 80.12 1.52 Example 7 0.97 80.59 2.07

[0065] As can be seen from the above table, in the process of reducing the acid value, the oil yield obtained by gradient heating is higher. This is because the oil and alkali solution are fully mixed at low temperature, and the saponification reaction is relatively mild at this time. As the temperature rises, the saponification reaction gradually intensifies, and excessive saponification is reduced as much as possible to increase the yield. If the temperature is too high, the saponification reaction is too intense, which will also lead to excessive saponification and reduce the yield, as shown in Example 2.

[0066] Regarding the selection of micro mixers, the mixing effect of the cross-finger micro mixer is better than that of the T-type micro mixer, so the oil acid value obtained by using the cross-finger micro mixer is lower.

[0067] In addition, the increase in channel size is not conducive to the uniform mixing of oil and alkali solution, resulting in an unsatisfactory reduction in acid value and a low yield.

[0068] In the process of reducing the peroxide value, increasing the temperature and extending the time can help reduce the peroxide value. Smaller channel size helps faster heat transfer, resulting in a lower peroxide value.

[0069] In summary, the method for reducing the acid value and peroxide value of oil based on microchannel reactor makes the alkali solution and oil quickly and evenly mix and react in the microchannel by means of gradient temperature increase, so as to prevent the problem of excessive saponification of oil. The saponification reaction is an exothermic reaction. The higher the temperature, the faster the reaction rate. At low temperature, oil and alkali solution can be quickly and fully mixed, while the saponification reaction is slow. As the temperature increases, the reaction rate gradually increases. The uniform mixing of alkali solution and oil greatly reduces the non-uniformity of the reaction and reduces local excessive saponification. In addition, the high heat transfer characteristics of the microchannel enable the heat released by the reaction to be transferred in time, avoiding the violent reaction caused by high temperature and further reducing excessive saponification. At the same time, because the reaction yield is high in the first microchannel, it is only necessary to centrifuge to remove the saponified product to directly reduce the peroxide value. Based on the fact that the oil in the microchannel is not affected by air, high-quality refined oil can be obtained by rapid temperature rise and decomposition and then rapid cooling.

[0070] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A method for reducing the acid value and peroxide value of oil based on a microchannel reactor, characterized in that: The steps include: Step S1, preparing sodium hydroxide solution and oil, and controlling the temperature range to be 40-65° C.; Step S2, conveying the sodium hydroxide solution and the oil to a micro mixer for mixed reaction, and flowing into the first micro channel for further reaction, wherein the micro mixer is placed in a 40-70° C. water bath environment, and the first micro channel includes a front section placed in a 40-75° C. water bath environment and a rear section placed in a 60-80° C. water bath environment, to obtain a mixed solution; Step S3, collecting the mixed liquid at the outlet of the first microchannel, and centrifuging to remove saponified matter and water to obtain deacidified oil; Step S4, transporting the deacidified oil to the second microchannel, wherein the second microchannel includes a front section placed in an oil bath environment of 150-250°C and a rear section placed in a water bath environment below 60°C, to obtain refined oil.

2. The method according to claim 1, characterized in that The micro mixer is any one of a T-type micro mixer, a Y-type micro mixer, a coaxial micro mixer and an interdigital micro mixer.

3. The method according to claim 1, characterized in that The oil comprises any one or more combinations of snake oil, lard, sheep oil, beef tallow, soybean oil, rapeseed oil, olive oil and peanut oil.

4. The method according to claim 1, characterized in that The material of the first microchannel is any one of polytetrafluoroethylene, polyperfluoroethylene propylene, polypropylene, and stainless steel; The material of the second microchannel includes stainless steel.

5. The method according to claim 1, characterized in that The diameter of the first microchannel is 0.3-10 mm; The diameter of the second microchannel is 0.3-10 mm.

6. The method according to claim 1, characterized in that The first microchannel has a front-end reaction time of 5-50s and a rear-end reaction time of 5-50s.

7. The method according to claim 1, characterized in that The mass ratio of the sodium hydroxide solution to the oil is 1:(5-25).

8. The method according to claim 1, characterized in that The front-end reaction time of the second microchannel is 5-500s.

9. The method according to claim 1, characterized in that The centrifugal speed in step S3 is 5000-20000 rpm, and the centrifugal time is 5-30 min.

10. A refined oil, characterized in that: The method according to any one of claims 1 to 9 is used to reduce the oil acid value and peroxide value of refined oils and fats.