Treatment method for reducing acid value of crude methyl ester
阅读说明：本技术 一种降低粗甲酯酸价的处理方法 (Treatment method for reducing acid value of crude methyl ester ) 是由 邓金华 钟民强 鲁昊 肖振 李进文 于 2021-10-08 设计创作，主要内容包括：本发明公开一种降低粗甲酯酸价的处理方法,属于生物柴油技术领域。本发明提出一种降低粗甲酯酸价的处理方法,包括以下步骤：S1、向粗甲酯中加入甲基磺酸催化剂并加热至110-150℃,之后加入甲醇蒸汽进行搅拌反应得到第一酯化油；S2、将所述第一酯化油降温至100℃以下,之后加入氧化钙进行搅拌反应得到降酸价后的第二酯化油。通过本发明提出的处理方法将粗甲酯的酸价降低至0.5KOH/(mg/g)以下。(The invention discloses a treatment method for reducing the acid value of crude methyl ester, belonging to the technical field of biodiesel. The invention provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps: s1, adding a methanesulfonic acid catalyst into the crude methyl ester, heating to 110-150 ℃, and then adding methanol steam to perform a stirring reaction to obtain first esterified oil; s2, cooling the first esterified oil to below 100 ℃, and then adding calcium oxide to carry out stirring reaction to obtain a second esterified oil with a reduced acid value. The acid value of the crude methyl ester is reduced to be below 0.5KOH/(mg/g) by the treatment method provided by the invention.)
1. A treatment method for reducing the acid value of crude methyl ester is characterized by comprising the following steps:
s1, adding a methanesulfonic acid catalyst into the crude methyl ester, heating to 110-150 ℃, and then adding methanol steam to perform a stirring reaction to obtain first esterified oil;
s2, cooling the first esterified oil to below 100 ℃, and then adding calcium oxide to carry out stirring reaction to obtain a second esterified oil with a reduced acid value.
2. The process of claim 1, wherein in step S1, the pressure of the stirring reaction is 0.1MPa to 0.11 MPa.
3. The method as claimed in claim 1, wherein the amount of the methanesulfonic acid added in step S1 is 0.1-0.5% by mass of the crude methyl ester.
4. The method as claimed in claim 3, wherein the amount of the methanesulfonic acid added in step S1 is 0.2-0.3% of the mass of the crude methyl ester.
5. The method as claimed in claim 1, wherein the pressure of the methanol vapor is 0.6-1.2MPa in step S1.
6. The method as claimed in claim 1, wherein in step S2, the amount of calcium oxide added is 0.15-0.5% of the mass of the first esterified oil.
7. The method as claimed in claim 1, wherein the time for adding the methanol vapor to perform the stirring reaction in step S1 is 60-180 min.
8. The method as claimed in claim 7, wherein the time for adding the methanol vapor to perform the stirring reaction in step S2 is 100-120 min.
9. The method as claimed in claim 1, wherein the time for adding the calcium oxide to perform the stirring reaction in step S2 is 30-40 min.
10. The method as claimed in claim 1, wherein the methyl ester is heated to 120-125 ℃ in step S1.
Technical Field
The invention relates to the technical field of biodiesel, in particular to a treatment method for reducing the acid value of crude methyl ester.
Background
The process for producing fatty acid methyl ester by using waste oil as a raw material and adopting a lipase method has the problem that the acid value of the prepared crude methyl ester is too high, the acid value of the generated crude methyl ester is usually 3-7KOH/(mg/g), the crude methyl ester with higher acid value cannot directly enter a distillation refining process, the acid value of the prepared biodiesel product can be ensured to be below 0.8KOH/(mg/g) by further reducing the acid value of the crude methyl ester to be below 0.5KOH/(mg/g), and the technical problem that the acid value of the crude methyl ester is difficult to reduce to be below 0.5KOH/(mg/g) exists in the prior art.
Disclosure of Invention
The invention aims to overcome the technical defects and provide a treatment method for reducing the acid value of crude methyl ester, which solves the technical problem that the acid value of the crude methyl ester is difficult to be reduced to be less than 0.5KOH/(mg/g) in the prior art.
In order to achieve the technical purpose, the technical scheme of the invention provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into the crude methyl ester, heating to 110-150 ℃, and then adding methanol steam to perform a stirring reaction to obtain first esterified oil;
s2, cooling the first esterified oil to below 100 ℃, and then adding calcium oxide to carry out stirring reaction to obtain a second esterified oil with a reduced acid value.
Further, in step S1, the pressure of the stirring reaction is 0.1MPa to 0.11 MPa.
Further, in step S1, the methanesulfonic acid is added in an amount of 0.1 to 0.5% by mass based on the mass of the crude methyl ester.
Further, in step S1, the addition amount of the methanesulfonic acid is 0.2 to 0.3% by mass of the crude methyl ester.
Further, in step S1, the pressure of the methanol vapor added is 0.6 to 1.2 MPa.
Further, in step S2, the addition amount of the calcium oxide is 0.15% to 0.5% of the mass of the first esterified oil.
Further, in step S1, the time for adding the methanol vapor to perform the stirring reaction is 60 to 180 minutes.
Further, in step S2, the time for adding the methanol vapor to perform the stirring reaction is 100-120 minutes.
Further, in step S2, the time for adding the calcium oxide to perform the stirring reaction is 30 to 40 minutes.
Further, in step S1, the methanesulfonic acid catalyst was added to the crude methyl ester and heated to 120-125 ℃.
Compared with the prior art, the invention has the beneficial effects that: firstly adding a methanesulfonic acid catalyst into crude methyl ester, heating to 110-150 ℃, then adding methanol steam to carry out stirring reaction, realizing esterification reaction of fatty acid in the crude methyl ester to obtain first esterified oil, greatly reducing the acid value of the crude methyl ester, wherein the main reason that the first esterified oil also has higher acid value is because fatty acid and methanesulfonic acid are remained, continuously cooling the first esterified oil to be below 100 ℃, adding calcium oxide into the first esterified oil, carrying out stirring reaction for 30-40 minutes to obtain second esterified oil with reduced acid value, reacting the calcium oxide with the fatty acid to generate calcium fatty acid soap, and reacting the methanesulfonic acid with the calcium oxide to generate calcium methylsulfonate soap to realize further reduction of the acid value, so that the acid value of the second esterified oil can be reduced to be below 0.5 KOH/(mg/g).
Detailed Description
The specific embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into the crude methyl ester and heating to 110-150 ℃, preferably 120-125 ℃; then adding methanol steam to carry out stirring reaction for 60-180 minutes, preferably for 100-120 minutes to obtain a first esterified oil; the pressure of the stirring reaction is 0.1MPa-0.11 MPa; the addition amount of the methanesulfonic acid is 0.1-0.5 percent of the mass of the crude methyl ester, and preferably 0.2-0.3 percent; the pressure of the methanol vapor is 0.6-1.2 MPa.
S2, cooling the first esterified oil to be below 100 ℃, adding calcium oxide, and stirring for reaction for 30-40 minutes to obtain a second esterified oil with a reduced acid value; the addition amount of the calcium oxide is 0.15-0.5% of the mass of the first esterified oil.
Reaction of fatty acid (RCOOH) with calcium oxide (CaO) to form calcium soap ((RCOO)2Ca) is an oil-soluble substance, and remains in the plant pitch in the subsequent distillation refining step, the residual fatty acid is further neutralized by calcium oxide, and methanesulfonic acid (methylsulfonic acid)CH3O3SH and calcium oxide (CaO) react to generate calcium methanesulfonate soap ((CH)3O3S)2Ca) is an oil-soluble substance which can be remained in the plant asphalt in the subsequent distillation and refining steps, and impurities can be prevented from entering the biodiesel product while the acid value is reduced.
The reaction equation is:
2RCOOH+CaO＝(RCOO)2Ca+H2O
2CH3O3SH+CaO＝(CH3O3S)2Ca+H2O
the acid value of the crude fatty acid methyl ester distillation refining must be below 0.5KOH/(mg/g) to ensure that the acid value of the biodiesel product is below 0.8 KOH/(mg/g).
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into crude methyl ester with an acid value of 4.8KOH/(mg/g), slowly heating to 125 ℃, adding methanol steam through a methanol steam distributor, stirring and reacting for 100 minutes to obtain first esterified oil, sampling and detecting the acid value, wherein the acid value is 0.8 KOH/(mg/g); the pressure of the stirring reaction is 0.102 MPa; the addition amount of the methanesulfonic acid is 0.3 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 1.0 MPa.
S2, cooling the first esterified oil to 90 ℃, adding calcium oxide, and carrying out stirring reaction for 30 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 0.34 KOH/(mg/g); the addition amount of the calcium oxide is 0.2 percent of the mass of the first esterified oil.
Example 2
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into crude methyl ester with an acid value of 5.1KOH/(mg/g), heating to 110 ℃, adding methanol steam, stirring and reacting for 180 minutes to obtain first esterified oil, and sampling to detect the acid value, wherein the acid value is 1.1 KOH/(mg/g); the pressure of the stirring reaction is 0.11 MPa; the addition amount of the methanesulfonic acid is 0.1 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 0.6 MPa.
S2, cooling the first esterified oil to 80 ℃, adding calcium oxide, and carrying out stirring reaction for 40 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 0.42 KOH/(mg/g); the addition amount of the calcium oxide is 0.5 percent of the mass of the first esterified oil.
Example 3
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into the crude methyl ester with the acid value of 3.9KOH/(mg/g), heating to 150 ℃, adding methanol steam, and carrying out stirring reaction for 60 minutes to obtain a first esterified oil, wherein the acid value of the first esterified oil is 0.9 KOH/(mg/g); the pressure of the stirring reaction is 0.105 MPa; the addition amount of the methanesulfonic acid is 0.2 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 1.2 MPa.
S2, cooling the first esterified oil to 95 ℃, adding calcium oxide, and carrying out stirring reaction for 35 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 0.35 KOH/(mg/g); the addition amount of the calcium oxide is 0.3 percent of the mass of the first esterified oil.
Example 4
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into the crude methyl ester with the acid value of 6.8KOH/(mg/g), heating to 130 ℃, adding methanol steam, and carrying out stirring reaction for 110 minutes to obtain a first esterified oil, wherein the acid value of the first esterified oil is 1.3 KOH/(mg/g); the pressure of the stirring reaction is 0.104 MPa; the addition amount of the methanesulfonic acid is 0.4 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 0.8 MPa.
S2, cooling the first esterified oil to 95 ℃, adding calcium oxide, and carrying out stirring reaction for 35 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 1.3 KOH/(mg/g); the addition amount of the calcium oxide is 0.15 percent of the mass of the first esterified oil.
Example 5
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into crude methyl ester with an acid value of 5.7KOH/(mg/g), heating to 110 ℃, adding methanol steam, stirring and reacting for 130 minutes to obtain first esterified oil, and sampling to detect the acid value, wherein the acid value is 1.4 KOH/(mg/g); the pressure of the stirring reaction is 0.107 MPa; the addition amount of the methanesulfonic acid is 0.1 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 0.9 MPa.
S2, cooling the first esterified oil to 85 ℃, adding calcium oxide, and carrying out stirring reaction for 40 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 0.48 KOH/(mg/g); the addition amount of the calcium oxide is 0.25 percent of the mass of the first esterified oil.
Example 6
The embodiment provides a treatment method for reducing the acid value of crude methyl ester, which comprises the following steps:
s1, adding a methanesulfonic acid catalyst into crude methyl ester with an acid value of 6.2KOH/(mg/g), heating to 110 ℃, adding methanol steam, stirring and reacting for 130 minutes to obtain first esterified oil, and sampling to detect the acid value, wherein the acid value is 1.3 KOH/(mg/g); the pressure of the stirring reaction is 0.107 MPa; the addition amount of the methanesulfonic acid is 0.1 percent of the mass of the crude methyl ester; the pressure of the methanol vapor fed through the methanol vapor distributor was 0.9 MPa.
S2, cooling the first esterified oil to 85 ℃, adding calcium oxide, and carrying out stirring reaction for 40 minutes to obtain a second esterified oil with a reduced acid value, wherein the acid value of the second esterified oil is 0.45 KOH/(mg/g); the addition amount of the calcium oxide is 0.25 percent of the mass of the first esterified oil.
The above-described embodiments of the present invention should not be construed as limiting the scope of the present invention. Any other corresponding changes and modifications made according to the technical idea of the present invention should be included in the protection scope of the claims of the present invention.