CN108949252B

CN108949252B - Preparation method of efficient composite alcohol-based fuel

Info

Publication number: CN108949252B
Application number: CN201810722619.1A
Authority: CN
Inventors: 曹大强
Original assignee: Anhui Shengbao New Energy Technology Co ltd
Current assignee: Anhui Shengbao New Energy Technology Co ltd
Priority date: 2018-07-03
Filing date: 2018-07-03
Publication date: 2021-05-11
Anticipated expiration: 2038-07-03
Also published as: CN108949252A

Abstract

The invention relates to a preparation method of an efficient composite alcohol-based fuel, which comprises the steps of sequentially adding methanol, concentrated sulfuric acid and levulinic acid into a reaction kettle with a condensation recovery device, heating materials in the reaction kettle to 65-70 ℃, and reacting for 6-8 hours; removing impurities from the product in the reaction kettle to obtain a premix containing methyl levulinate and methanol; and mixing the premix and veratrole, and stirring uniformly to obtain the finished product. The methyl levulinate is synthesized and converted into methyl levulinate by utilizing levulinic acid and methanol, and then the impurity removal process of the methyl levulinate is optimized, so that the impurity removal of the methyl levulinate can be realized without rectification; compared with direct methanol combustion, the fuel evaporation rate of the composite alcohol-based fuel is reduced by 67%. High fuel utilization rate and good combustion effect.

Description

Preparation method of efficient composite alcohol-based fuel

Technical Field

The invention relates to the technical field of alcohol-based fuels, in particular to a preparation method of an efficient composite alcohol-based fuel.

Background

Alcohol-based fuels are fuels that are formulated primarily with alcohols (e.g., methanol, ethanol, butanol, etc.). The biofuel has lower combustion value than liquefied gas and diesel oil, but has higher price, can be used as the substitute fuel of liquefied petroleum gas and diesel oil, is low in price, safe and convenient, has no residue and residual liquid and no black pan bottom, has the characteristics of cleanness, sanitation, safety, low price, easily purchased raw materials, convenient use and the like, has the cost of about one third of the wholesale price of liquefied petroleum gas or diesel oil, has huge profit space and has extremely high investment value.

Methyl levulinate as an important platform compound in the biomass conversion process has wide application, and can be used as food additives, spices, gasoline additives, biofuels and the like. At present, the methods for preparing high value-added chemical levulinic acid esters through a biomass approach mainly include a levulinic acid esterification method and a direct alcoholysis method, wherein the levulinic acid esterification method generally comprises the step of reacting levulinic acid with methanol under the catalytic action of acid to generate methyl levulinate. Levulinic acid is a product obtained by converting wood fiber of renewable materials such as straws and the like into a liquid state, and has the advantages of renewability and wide raw material sources.

In the alcohol-based fuel, methanol is directly combusted to gasify part of methanol due to the very low boiling point of the methanol in the combustion process, so that a large amount of waste is caused, and the loss of the fuel is very high. Moreover, if the methanol vapor is inhaled by human body in a large amount, the methanol vapor also has influence on human health. Therefore, how to reduce the fuel loss rate of the alcohol-based fuel containing methanol is the greatest importance of the popularization of the alcohol-based fuel at present.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of an efficient composite alcohol-based fuel, which has the following specific technical scheme:

a preparation method of a high-efficiency composite alcohol-based fuel comprises the following steps:

step one, adding 50-1170 parts by mass of methanol, 6.7-9.8 parts by mass of 98% concentrated sulfuric acid and 120 parts by mass of levulinic acid into a reaction kettle with a condensation recovery device in sequence, and heating materials in the reaction kettle to 65-70 ℃ for reaction for 6-8 hours;

step two, removing impurities from the product in the reaction kettle to obtain a premix containing methyl levulinate and methanol;

and step three, mixing and stirring the premix and veratrole uniformly to obtain a finished product.

As an improvement of the above technical solution, the operation process of the impurity removal process in the second step is as follows: dehydrating a product in a reaction kettle by using water-absorbent resin to obtain a mixed solution, adding anhydrous barium chloride into the mixed solution, and stirring to generate a mixture containing precipitates, wherein the mass ratio of the mixed solution to the anhydrous barium chloride is (15-130) to (6-7.5); and filtering the mixture containing the precipitate by using filter paper to remove the precipitate to obtain the premix.

As an improvement of the technical scheme, in the step three, the mass ratio of the premix to the veratrole is 100: 26-29.

The invention has the beneficial effects that: according to the invention, renewable biomass raw materials, namely levulinic acid and methanol, are synthesized and converted into methyl levulinate, and then the impurity removal process of methyl levulinate is optimized, so that the impurity removal of methyl levulinate can be achieved without rectification; compared with direct methanol combustion, the fuel evaporation rate of the composite alcohol-based fuel is reduced by 67%. High fuel utilization rate and good combustion effect.

Detailed Description

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

Step one, adding 50 parts by mass of methanol, 6.7 parts by mass of 98% concentrated sulfuric acid and 120 parts by mass of levulinic acid into a reaction kettle with a condensation recovery device in sequence, and heating materials in the reaction kettle to 65-70 ℃ for reaction for 6 hours. The reaction yielded methyl levulinate in 63.3% yield.

Step two, dehydrating the product in the reaction kettle by using water-absorbing resin to obtain a mixed solution, adding anhydrous barium chloride into the mixed solution, and stirring to generate a mixture containing precipitates, wherein the mass ratio of the mixed solution to the anhydrous barium chloride is 15: 6; the mixture containing the precipitate was filtered using filter paper to remove the precipitate to give a premix containing methyl levulinate and methanol.

And step three, mixing and stirring the premix and veratrole uniformly according to the mass ratio of 100: 26 to obtain a finished product.

Example 2

Step one, adding 500 parts by mass of methanol, 8.9 parts by mass of 98% concentrated sulfuric acid and 120 parts by mass of levulinic acid into a reaction kettle with a condensation recovery device in sequence, and heating materials in the reaction kettle to 65-70 ℃ for reaction for 7 hours. The reaction yielded methyl levulinate in 64.1% yield.

Step two, dehydrating the product in the reaction kettle by using water-absorbing resin to obtain a mixed solution, adding anhydrous barium chloride into the mixed solution, and stirring to generate a mixture containing precipitates, wherein the mass ratio of the mixed solution to the anhydrous barium chloride is 70: 7; filtering the mixture containing the precipitate by using filter paper to remove the precipitate to obtain a premix, wherein the premix contains methyl levulinate and methanol;

and step three, mixing and stirring the premix and veratrole uniformly according to the mass ratio of 100: 28 to obtain a finished product.

Example 3

Step one, 1170 parts by mass of methanol, 9.8 parts by mass of concentrated sulfuric acid with the mass fraction of 98% and 120 parts by mass of levulinic acid are sequentially added into a reaction kettle with a condensation recovery device, and materials in the reaction kettle are heated to 65-70 ℃ for reaction for 8 hours. The reaction yielded methyl levulinate in 63.7% yield.

Step two, dehydrating the product in the reaction kettle by using water-absorbing resin to obtain a mixed solution, adding anhydrous barium chloride into the mixed solution, and stirring to generate a mixture containing precipitates, wherein the mass ratio of the mixed solution to the anhydrous barium chloride is 130: 7.5; the mixture containing the precipitate was filtered using filter paper to remove the precipitate to give a premix containing methyl levulinate and methanol.

And step three, mixing and stirring the premix and veratrole uniformly according to the mass ratio of 100: 29 to obtain a finished product.

Combustion loss experiment 1

The finished product from example 2 was used to heat 10kg of water from 25 ℃ to 100 ℃ using an alcohol based fuel cooker. After the experiment, 201.7g of the required finished product is obtained. And only 168.3g of finished product is theoretically required to be calculated according to the combustion heat of each component in the finished product. The heat loss rate of the finished product is 16.6%. Wherein, the finished product heat loss comprises insufficient combustion of the alcohol-based fuel stove, combustion heat loss and fuel evaporation rate.

Combustion loss experiment 2

10kg of water was heated from 25 ℃ to 100 ℃ with methanol using an alcohol based fuel range. After the experiment, 283.9g of methanol was required. And based on the calculation of the combustion heat of the methanol, only 139g of methanol is theoretically needed. The heat loss rate of methanol was 51%. Wherein, the methanol heat loss comprises insufficient combustion of the alcohol-based fuel stove, combustion heat loss and fuel evaporation rate.

Combustion loss experiment 3

Taking the product in the reaction kettle in the step one in the embodiment 2, rectifying the product to obtain methyl levulinate and methanol, mixing the methyl levulinate and the methanol to obtain a control premix, and mixing and stirring the control premix and veratrole uniformly according to the mass ratio of 100: 28 to obtain a control product.

An alcohol-based fuel range was used to heat 10kg of water from 25 ℃ to 100 ℃ with the control. 266.7g of the required control product is obtained through experiments. According to the calculation of the combustion heat of each component in the reference substance, only 162.9g of the reference substance is theoretically required. The heat loss rate of the control was 38.9%. Wherein, the finished product heat loss comprises insufficient combustion of the alcohol-based fuel stove, combustion heat loss and fuel evaporation rate.

Combustion loss experiment 4

And (3) taking a reference substance in the combustion loss experiment 3, adding barium chloride into the reference substance, wherein the mass ratio of the barium chloride to the reference substance is 1: 99, and stirring to completely dissolve the barium chloride in the reference substance to obtain a verification sample.

An alcohol-based fuel cooker was used to heat 10kg of water from 25 ℃ to 100 ℃ with a validation sample. Through the experiment, 198.9g of sample needs to be verified. According to the calculation of the combustion heat of each component in the reference substance, only 164.5g of the sample is theoretically verified. The heat loss rate of the control was 17.3%. Wherein, the finished product heat loss comprises insufficient combustion of the alcohol-based fuel stove, combustion heat loss and fuel evaporation rate.

In the above examples, methanol and levulinic acid are catalyzed by concentrated sulfuric acid to generate methyl levulinate and water; wherein the yield of methyl levulinate does not exceed 65%. The yield of methyl levulinate is the percentage between the mass of methyl levulinate and the total mass of reactants, which is the total mass of methanol and levulinic acid. The method for measuring the yield of the methyl levulinate can be realized by firstly sampling the inside of a reaction kettle, then distilling out the mass of a sample of the methyl levulinate in a laboratory and then calculating the mass of the product methyl levulinate.

Due to the addition of veratrole, the flame temperature of the composite alcohol-based fuel reaches 1100-1200 ℃.

In the impurity removal process, products in the reaction kettle are firstly dehydrated by using water-absorbing resin to obtain mixed liquid. This dehydration step is intended to prevent subsequent hydrolysis of the methyl levulinate in an alkaline environment. The mixed liquid comprises methanol, methyl levulinate and residual levulinic acid. Since anhydrous barium chloride is soluble in methanol, it is insoluble in methyl levulinate. Adding anhydrous barium chloride into the mixed solution, wherein the content of methanol in the mixed solution is enough, so that the anhydrous barium chloride can be completely dissolved in the methanol, barium ions and levulinate ions are combined in the methanol solution of the barium chloride to generate barium levulinate which is slightly dissolved in the methanol, and when the content of the barium levulinate in the methanol exceeds the solubility of the barium levulinate, barium levulinate precipitation is generated; that is, the barium ion combines with the levulinate ion to form a barium levulinate precipitate, which gives the majority of the levulinic acid to be removed, while the by-product hydrogen chloride dissolves in methanol. After the impurity removal process, the content of the levulinic acid in the premix is not more than 0.5 per mill, and subsequent combustion is not influenced.

In the combustion loss experiment 1, the combustion loss experiment 2 and the combustion loss experiment 3, because the alcohol-based fuel stove is the same stove and then is subjected to experiments in the same environment, the alcohol-based fuel stove can be identified to be the same in each experiment due to insufficient combustion and combustion heat loss; it follows that the difference between the heat loss rates of the fuels is only related to the evaporation of the fuel and is positive. As can be seen from the analysis of the combustion loss experiment 2: methanol is used as a fuel only, and the evaporation loss amount of the methanol is very large during combustion. By comparing the combustion loss experiment 2 and the combustion loss experiment 3, it can be seen that: the addition of methyl levulinate to replace partial methanol can reduce the evaporation amount of fuel and raise the utilization rate of fuel. By comparing the combustion loss test 1 and the combustion loss test 3, it can be seen that: the finished product of the invention also contains a barium salt dissolved in methanol relative to a mixture of methyl levulinate and methanol, so that the evaporation amount of the fuel is obviously reduced; further, the combustion loss experiment 4 further demonstrated that the addition of barium chloride brought the heat loss rate (17.3%) of the fuel in the combustion loss experiment 4 close to the heat loss rate (16.6%) of the combustion loss experiment 1.

In the invention, water and most of levulinic acid can be removed through an impurity removal process, and barium chloride is introduced into the system at the same time. The methyl levulinate and the methanol are separated without rectification in the whole process, and compared with a rectification tower with high price, the method does not need to build and purchase rectification equipment with large volume and high cost. Compared with direct methanol combustion, the fuel evaporation rate of the composite alcohol-based fuel is reduced by 67%, the fuel utilization rate of the composite alcohol-based fuel is high, and the combustion effect is good.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. The preparation method of the high-efficiency composite alcohol-based fuel is characterized by comprising the following steps:

step three, mixing and stirring the premix and veratrole uniformly to obtain a finished product;

the operation process of the impurity removal process in the second step is as follows: dehydrating a product in a reaction kettle by using water-absorbing resin to obtain a mixed solution, adding anhydrous barium chloride into the mixed solution, and stirring to generate a mixture containing precipitates, wherein the mass ratio of the mixed solution to the anhydrous barium chloride is (15-130) to (6-7.5); filtering the mixture containing the precipitate by using filter paper to remove the precipitate to obtain the premix;

in the third step, the mass ratio of the premix to the veratrole is 100 (26-29).