AU2021100018A4

AU2021100018A4 - Extracting desulfurizing agent, preparation method thereof and desulfurizing refining method of biodiesel

Info

Publication number: AU2021100018A4
Application number: AU2021100018A
Authority: AU
Inventors: Changzhu Li; Li Li; Peiwang LI; Zhihong XIAO; Aihua Zhang
Original assignee: Hunan Academy of Forestry
Current assignee: Hunan Academy of Forestry
Priority date: 2021-01-04
Filing date: 2021-01-04
Publication date: 2021-04-22
Anticipated expiration: 2029-01-04

Abstract

The present invention belongs to the field of deep processing of biomass energy liquid fuel, and discloses an extracting desulfurizing agent, a preparation method thereof and a desulfurizing refining method of biodiesel. The extracting desulfurizing agent is liquid ionic inorganic salt and is synthesized by carrying out a reaction on a precursor A and sodium tetrafluoroborate according to a mass ratio of (40-50): (50-70). The precursor A is 1-butyl-3-methylimidazole bromide or 1-propyl-3-methylimidazole bromide. The desulfurizing refining method of the biodiesel includes: adding an extracting desulfurizing agent and an accelerant for extracting reaction into the biodiesel; and leaving the biodiesel for standing and layering after the reaction to separate the biodiesel. The liquid ionic inorganic salt can remove sulfur content in the biodiesel effectively, and the two phases are extremely easy to separate, so that an emulsion phenomenon can be avoided effectively. The present invention reduces the sulfur content of the biodiesel by using the liquid ionic inorganic salt for extraction and can reduce the sulfur content in the biodiesel by more than 90%. The present invention has the advantages of low energy consumption, low refining consumption and no pollution. Drawings of Description Accelerant Precursor A Liquid - ~ ionic Additive BC ~ inorgatc Biodiesel salt O So dium tetrafluoroborate Separation Desulfunzat . ..---. ion at a Blending high temperature Fig. 1 1

Description

Drawings of Description

Accelerant

Precursor A Liquid - ~ ionic Additive BC ~ inorgatc Biodiesel salt O

So dium Separation tetrafluoroborate

Desulfunzat . ..---. ion at a Blending high temperature

Fig. 1

Description

EXTRACTING DESULFURIZING AGENT, PREPARATION METHOD THEREOF AND DESULFURIZING REFINING METHOD OF BIODIESEL

Technical Field

The present invention belongs to the field of deep processing of biomass energy liquid fuel, and particularly relates to an extracting desulfurizing agent, a preparation method thereof and a desulfurizing refining method of biodiesel.

Background

Biomass energy is a core component of global renewable resources and also one of basic resources for human survival and development, which is second only to coal, petroleum and natural gas. With the rapid development of the economic globalization, while enjoying the achievements brought by science and technology, the human beings are also forced to bear the double pressure of energy shortage and environmental deterioration. In recent years, under the support of the technology, policy and market, Chinese government has attached great importance to the development and utilization of biomass resources, has successively issued a series of strategic plans and guiding policies, and proposed clear goals and requirements for the development of biomass energy in different fields. Biodiesel is a long-chain fatty acid methyl ester formed by transesterification of triglyceride of animals and plants and methanol, which is a typical "green energy", and has the characteristics of good environmental protection performance, good engine starting performance, good fuel performance, wide source of raw materials and renewability. Vigorously developing the biodiesel has important strategic significance for the sustainable economic development, promotion of energy substitution, reduction of environmental pressure and control of urban air pollution. Although a sulfur content of the biodiesel is far lower than that of fossil fuels, it is necessary to control sulfur elements in fuels in the new century with increasingly severe environmental awareness. The sulfur elements in the biodiesel mainly exist in a form of organic sulfur. The excessively high content of sulfur not only affects the quality of the biodiesel, but also has strong corrosion to metal equipment, which can seriously affect the service life of engines. Especially, active sulfur-containing compounds have direct corrosion to metals, such as thioalcohol, elemental sulfur, hydrogen sulfide, etc. Sulfur oxides such as SO2 and S03 formed after the burning of the sulfur-containing compounds not only seriously corrode parts in high

Description

temperature areas, but also may react with lubricating oil on air cylinder walls to accelerate the generation of a paint film and the accumulation of carbon deposits. At present, the biodiesel is blended with diesel and then enters sales channels. A main specification is BD5, which contains 5% of biodiesel and 95% of 04 diesel. Since 2017, the national-V standard for gasoline and diesel in China has been fully implemented. The sulfur content is a most critical environmental protection index in automotive oil products. In order to further improve the capacity of an automobile exhaust purification system and reduce the emission of automobile pollutants, the standard reduces the limit of sulfur content index from 50 ppm at the fourth stage to 10 ppm, which is reduced by 80%. Conventional desulfurization mainly adopts catalytic hydrogenation or selective adsorption desulfurization, which is high in energy consumption, high in refining consumption and easy to cause pollution.

Summary

The present invention provides an extracting desulfurizing agent. The extracting desulfurizing agent is liquid ionic inorganic salt which is synthesized by carrying out a reaction on a precursor A and sodium tetrafluoroborate. A mass ratio of the precursor A to sodium tetrafluoroborate is (40-50): (50-70). In the above extracting desulfurizing agent, raw material components of the precursor A include 30-50 parts of1-methylimidazole and 40-60 parts of N-bromobutane or bromopropane. In the above extracting desulfurizing agent, the precursor A is1-butyl-3-methylimidazole bromide or 1-propyl-3-methylimidazole bromide. Further, the present invention also provides a preparation method of the extracting desulfurizing agent. The method includes the following steps: (1) preparing a precursor A: carrying out a reaction on 1-methylimidazole and N-bromobutane or bromopropane; after the reaction, leaving a mixed solution for standing and layering, collecting a lower solution to stand until white solids are precipitated, recrystallizing with an additive B, and drying by rotary evaporation to obtain a white solid precursor A; (2) placing the above precursor A and sodium tetrafluoroborate in an acetone solvent for reaction under a stirring condition to obtain yellow viscous liquid, washing the obtained liquid with an additive C, and carrying out the rotary evaporation to obtain a bright yellow clear product. In the above preparation method of the extracting desulfurizing agent, a mass ratio of 1-methylimidazole to N-bromobutane or bromopropane in the step (1) is (30-50): (40-60).

Description

In the above preparation method of the extracting desulfurizing agent, reaction conditions in the step (1) are: a reaction temperature is 30-60 °C, and the reaction time is 3-8 h. In the above preparation method of the extracting desulfurizing agent, the standing conditions for the lower solution in the step (1) are: a reaction temperature is 10-30 °C, and the standing time is 12-36 h. In the above preparation method of the extracting desulfurizing agent, components of the additive B in the step (1) include 20-40 parts of acetonitrile, 20-40 parts of ethyl acetate and -30 parts of acetone. In the above preparation method of the extracting desulfurizing agent, the additive B in the step (1) is prepared by the following steps: mixing the acetonitrile, the ethyl acetate and the acetone at a room temperature, increasing the temperature to 40-80 °C, refluxing for 60-100 min, standing, and slowing cooling for standby use. In the above preparation method of the extracting desulfurizing agent, a recrystallization operation in the step (1) is to carry out the recrystallization for 1-2 times at the temperature of -25 °C. In the above preparation method of the extracting desulfurizing agent, a rotary evaporation operation in the step (1) is to carry out the vacuum drying for 1-3 h on a rotary evaporator at the temperature of 40-90 °C. In the above preparation method of the extracting desulfurizing agent, a mass ratio of the precursor A to sodium tetrafluoroborate in the step (2) is (40-50): (50-70). In the above preparation method of the extracting desulfurizing agent, the consumption of the acetone in the step (2) is 1/4-1/2 of a total mass of the precursor A and the sodium tetrafluoroborate. In the above preparation method of the extracting desulfurizing agent, the reaction conditions in the step (2) are: a reaction temperature is 10-40 °C, and the electromagnetic stirring time is 8-20 h. In the above preparation method of the extracting desulfurizing agent, components of the additive C in the step (2) include 40-60 parts of dichloromethane and 30-50 parts of trichloromethane. In the above preparation method of the extracting desulfurizing agent, the additive C in the step (2) is prepared by the following steps: uniformly stirring dichloromethane and trichloromethane in an explosion-proof closed stirring kettle at the temperature of 20-25 °C, and standing for standby use.

Description

In the above preparation method of the extracting desulfurizing agent, a washing operation of the additive C in the step (2) is to wash for 1-3 times with the additive C of 2-3 times of volume. In the above preparation method of the extracting desulfurizing agent, the rotary evaporation operation in the step (2) is to carry out the rotary evaporation for 50-100 min under a vacuum condition at the temperature of 80-100 °C. Further, the present invention also provides a desulfurizing refining method of biodiesel. The method includes the following steps: (1) preheating the biodiesel in a reactor, and carrying out distillation under reduced pressure until there is no bubble generated on a liquid surface; (2) when cooling water in a sandwich layer of the reactor is cooled to 40-70 °C, adding an extracting desulfurizing agent into the biodiesel, and adding an accelerant for extracting reaction during the continuous stirring; after the reaction, carrying out the standing and layering to separate the biodiesel, and recycling the extracting desulfurizing agent from the lower layer. In the above desulfurizing refining method of the biodiesel, in the step (1), the biodiesel is preheated to 100-120 °C, and distilled under reduced pressure for 1-5 h. In the above desulfurizing refining method of the biodiesel, the consumption of the extracting desulfurizing agent in the step (2) is 10-20 % of the mass of the biodiesel; and the extracting desulfurizing agent has the meaning as described above. In the above desulfurizing refining method of the biodiesel, a continuous stirring operation in the step (2) is to carry out the continuous stirring for 60-120 min at a rotation speed of 200-1000 r/min. In the above desulfurizing refining method of the biodiesel, the accelerant in the step (2) is hydrogen peroxide. A concentration of the hydrogen peroxide is 0.1-1% by mass. The above desulfurizing refining method of the biodiesel further includes: after the step (2), repeating the operations in the step (1) and step (2) for 2-5 times, and determining a sulfur content of the biodiesel. The present invention has the beneficial effects: (1) The extracting desulfurizing agent of the present invention, i.e. the liquid ionic inorganic salt can remove the sulfur content in the biodiesel effectively, and the two phases are extremely easy to separate, so that an emulsion phenomenon can be avoided effectively. (2) Raw materials involved in the present invention are low in price, safe and environment-friendly, and the used process is simple and convenient.

A

Description

(3) The present invention reduces the sulfur content of the biodiesel by using the liquid ionic inorganic salt for extraction and can reduce the sulfur content in the biodiesel by more than %. Compared with the conventional hydrogenation desulfurization or wet-method desulfurization, the method of the present invention has the advantages of low energy consumption, low refining consumption and no pollution. No sewage is produced in the entire refining process, so that enterprises do not need to spend a great amount of financial and material resources to solve the environmental protection problem caused by the waste water.

Description of Drawings

To more clearly describe the technical solutions in the embodiments of the present invention or in the prior art, the drawings required to be used in the description of the embodiments or in the prior art will be simply presented below. Apparently, the following drawings show some embodiments of the present invention, so for those ordinary skilled in the art, other drawings can also be obtained according to these drawings without contributing creative labor. Fig. 1 is a flow chart of a desulfurizing refining method of biodiesel according to embodiment 1 of the present invention.

Detailed Description

The present invention provides an extracting desulfurizing agent. The extracting desulfurizing agent is liquid ionic inorganic salt which is synthesized by carrying out a reaction on a precursor A and sodium tetrafluoroborate. A mass ratio of the precursor A to sodium tetrafluoroborate is (40-50): (50-70). Raw material components of the precursor A include 30-50 parts of1-methylimidazole and -60 parts of N-bromobutane or bromopropane. In the above extracting desulfurizing agent, the precursor A is 1-butyl-3-methylimidazole bromide or 1-propyl-3-methylimidazole bromide. Further, the present invention also provides a preparation method of the extracting desulfurizing agent. The method includes the following steps: (1) A precursor A is prepared: 1-methylimidazole and N-bromobutane or bromopropane in a ratio of (30-50): (40-60) are stirred for reaction; after the reaction, a mixed solution stands for layering; a lower solution is collected and stands until white solids are precipitated; the white

Description

solids are recrystallized with an additive B, and the recrystallized mixture is dried by rotary evaporation to obtain a white solid precursor A. Components of the additive B include 20-40 parts of acetonitrile, 20-40 parts of ethyl acetate and 20-30 parts of acetone. (2) Under a stirring condition, the above precursor A and sodium tetrafluoroborate are placed in an acetone solvent for reaction according to a mass ratio of (40-50): (50-70) to obtain yellow viscous liquid; and the obtained liquid is washed with an additive C and then subjected to rotary evaporation to obtain a bright yellow clear product. The components of the additive C include 40-60 parts of dichloromethane and 30-50 parts of trichloromethane. In the above preparation method of the extracting desulfurizing agent, reaction conditions in the step (1) are: a reaction temperature is 30-60 °C, and the reaction time is 3-8 h. In the above preparation method of the extracting desulfurizing agent, the standing conditions for the lower solution in the step (1) are: a reaction temperature is 10-30 °C, and the standing time is 12-36 h. In the above preparation method of the extracting desulfurizing agent, the additive B in the step (1) is prepared by the following steps: the acetonitrile, the ethyl acetate and the acetone are mixed at a room temperature; the temperature increases to 40-80 °C; refluxing is carried out for -100 min; and a mixed solution stands and is slowly cooled for standby use In the above preparation method of the extracting desulfurizing agent, a recrystallization operation in the step (1) is to carry out the recrystallization for 1-2 times at the temperature of -25 °C. The rotary evaporation operation is to carry out the vacuum drying on a rotary evaporator for 1-3 h at 40-90°C. In the above preparation method of the extracting desulfurizing agent, the consumption of the acetone in the step (2) is 1/4-1/2 of a total mass of the precursor A and the sodium tetrafluoroborate. In the above preparation method of the extracting desulfurizing agent, the reaction conditions in the step (2) are: a reaction temperature is 10-40 °C, and the electromagnetic stirring time is 8-20 h. In the above preparation method of the extracting desulfurizing agent, the additive C in the step (2) is prepared by the following steps: dichloromethane and trichloromethane are uniformly stirred in an explosion-proof closed stirring kettle at the temperature of 20-25 °C, and stand for standby use. In the above preparation method of the extracting desulfurizing agent, a washing operation of the additive C in the step (2) is to wash for 1-3 times with the additive C of 2-3 times of

t,

Description

volume.The rotary evaporation operation is to carry out rotary evaporation for 50-100 min under a vacuum condition at 80-100 °C. Further, the present invention also provides a desulfurizing refining method of biodiesel. The method includes the following steps: (1) Biodiesel is preheated to 100-120 °C in a reactor, and then distilled under reduced pressure for 1-5 h until there is no bubble generated on a liquid surface. (2) When cooling water in a sandwich layer of the reactor is cooled to 40-70 °C, an extracting desulfurizing agent is added into the biodiesel, and an accelerant for extracting reaction is added during the continuous stirring; after the reaction, an obtained mixed solution stands for layering to separate the biodiesel, and the extracting desulfurizing agent is recycled from the lower layer. In the above desulfurizing refining method of the biodiesel, the consumption of the extracting desulfurizing agent in the step (2) is 10-20 % of the mass of the biodiesel; and the extracting desulfurizing agent has the meaning as described above. In the above desulfurizing refining method of the biodiesel, a continuous stirring operation in the step (2) is to carry out the continuous stirring for 60-120 min at a rotation speed of 200-1000 r/min. In the above desulfurizing refining method of the biodiesel, the accelerant in the step (2) is hydrogen peroxide. A concentration of the hydrogen peroxide is 0.1-1% by mass. The above desulfurizing refining method of the biodiesel further includes: after the step (2), repeating the operations in the step (1) and step (2) for 2-5 times, and determining a sulfur content of the biodiesel. The technical solutions of the present invention are further described in detail below in combination with specific embodiments. The embodiments described below are only used to exemplarily explain and interprete the present invention, but shall not be construed as limiting the protection scope of the present invention. All technologies implemented on the basis of the above contents of the present invention are contained in the protection scope of the present invention. Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercial products, or can be prepared by known methods. The sulfur content in the present invention is detected by an Elementar Trace SN ultraviolet-fluorescent sulfur detector of Germany. Preparation example 1

'7

Description

An extracting desulfurizing agent was prepared through the following steps: Components of a precursor A include 45 parts of 1-methylimidazole and 55 parts of N-bromobutane or bromopropane. Components of an additive B include 40 parts of acetonitrile, 40 parts of ethyl acetate and parts of acetone. Components of the additive C (a stabilizer C) include 50 parts of dichloromethane and 50 parts of trichloromethane. The precursor A, sodium tetrafluoroborate (1.2 times of a molar mass of the precursor A) and acetone (1/3 of a total mass of the raw materials) serving as a solvent reacted, and the reacting solution was electromagnetically stirred for 15 h at 20 °C to obtain yellow viscous liquid. The obtained liquid was washed twice with the additive C of 3 times of volume. The yellow viscous liquid was subjected to rotary evaporation for 60 min under a vacuum condition at 80°C to obtain a bright yellow clear product. Embodiment 1 Desulfurizing refining method of biodiesel - extracting desulfurizing process The biodiesel was prepared from swill-cooked dirty oil raw material with a sulfur content of 1.73 mg/L. The raw material biodiesel was preheated to 120 °C in a reactor with a sandwich layer, and after the distillation under reduced pressure for 2 h, there was no residual methanol and water. The raw material biodiesel was cooled to 50 °C and liquid ionic inorganic salt with a mass fraction of 18% was added. The mixture was continuously stirred for 100 min at a rotation speed of 800 r/min; hydrogen peroxide with a mass fraction of 0.5% was dropwise added as an accelerant for extracting reaction during the stirring; after the reaction, the solution stood for layering to separate the biodiesel, and the liquid ionic inorganic salt was recycled from the lower layer. The extracting desulfurization was repeated for three times under the same conditions. The sulfur content of the refined biodiesel was 0.14 mg/L after detection. Embodiment 2 The biodiesel was prepared from plant residual waste, i.e., acid oil, with a sulfur content of raw material of 14.89 mg/L. The refining was carried out in the same steps as the embodiment 1. The sulfur content of the refined biodiesel was 0.21 mg/L by detection. The embodiments of the present invention are described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Q

Claims

1. An extracting desulfurizing agent, which is liquid ionic inorganic salt and synthesized by carrying out a reaction on a precursor A and sodium tetrafluoroborate, wherein a mass ratio of the precursor A to sodium tetrafluoroborate is (40-50): (50-70).

2. The extracting desulfurizing agent according to claim 1, wherein raw material components of the precursor A comprise 30-50 parts of 1-methylimidazole and 40-60 parts of N-bromobutane or bromopropane; preferably, the precursor A is 1-butyl-3-methylimidazole bromide or 1-propyl-3-methylimidazolebromide.

3. A preparation method of the extracting desulfurizing agent of claim 1 or 2, comprising the following steps: (1) preparing a precursor A: carrying out a reaction on 1-methylimidazole and N-bromobutane or bromopropane; after the reaction, leaving a mixed solution for standing and layering, collecting a lower solution to stand until white solids are precipitated, recrystallizing with an additive B, and drying by rotary evaporation to obtain a white solid precursor A; (2) placing the above precursor A and sodium tetrafluoroborate in an acetone solvent for reaction under a stirring condition to obtain yellow viscous liquid, washing the obtained liquid with an additive C, and carrying out the rotary evaporation to obtain a bright yellow clear product.

4. The preparation method of the extracting desulfurizing agent according to claim 3, wherein a mass ratio of 1-methylimidazole to N-bromobutane or bromopropane in the step (1) is (30-50): (40-60); reaction conditions are: a reaction temperature is 30-60 °C, and the reaction time is 3-8 h; the standing conditions for the lower solution are: a reaction temperature is 10-30 °C, and the standing time is 12-36 h; a recrystallization operation is to carry out the recrystallization for 1-2 times at the temperature of 15-25 °C; a rotary evaporation operation is to carry out the vacuum drying for 1-3 h on a rotary evaporator at the temperature of 40-90 °C.

5. The preparation method of the extracting desulfurizing agent according to claim 3 or 4, wherein components of the additive B in the step (1) comprise 20-40 parts of acetonitrile, 20-40 parts of ethyl acetate and 20-30 parts of acetone;

Claims

the additive B is prepared by the following steps: mixing the acetonitrile, the ethyl acetate and the acetone at a room temperature, increasing the temperature to 40-80 °C, refluxing for -100 min, standing, and slowing cooling for standby use.

6. The preparation method of the extracting desulfurizing agent according to claim 3 or 4, wherein a mass ratio of the precursor A to sodium tetrafluoroborate in the step (2) is (40-50): (50-70); the consumption of the acetone is 1/4-1/2 of a total mass of the precursor A and the sodium tetrafluoroborate; the reaction conditions are: a reaction temperature is 10-40 °C, and the electromagnetic stirring time is 8-20 h; a washing operation of the additive C is to wash for 1-3 times with the additive C of 2-3 times of volume; the rotary evaporation operation is to carry out the rotary evaporation for 50-100 min under a vacuum condition at the temperature of 80-100 °C.

7. The preparation method of the extracting desulfurizing agent according to claim 3 or 6, wherein components of the additive C in the step (2) comprise 40-60 parts of dichloromethane and 30-50 parts of trichloromethane; the additive C is prepared by the following steps: uniformly stirring dichloromethane and trichloromethane in an explosion-proof closed stirring kettle at the temperature of 20-25 °C, and standing for standby use.

8. A desulfurizing refining method of biodiesel, comprising the following steps: (1) preheating the biodiesel in a reactor, and carrying out distillation under reduced pressure until there is no bubble generated on a liquid surface; (2) when cooling water in a sandwich layer of the reactor is cooled to 40-70 °C, adding an extracting desulfurizing agent into the biodiesel, and adding an accelerant for extracting reaction during the continuous stirring; after the reaction, carrying out the standing and layering to separate the biodiesel; and recycling the extracting desulfurizing agent from the lower layer, wherein in the above desulfurizing refining method of the biodiesel, in the step (1), the biodiesel is preheated to 100-120 °C, and distilled under reduced pressure for 1-5 h; a continuous stirring operation in the step (2) is to carry out the continuous stirring for -120 min at a rotation speed of 200-1000 r/min; the accelerant is hydrogen peroxide, and a concentration of the hydrogen peroxide is 0.1-1% by mass.

Claims

9. The desulfurizing refining method of biodiesel according to claim 8, wherein the consumption of the extracting desulfurizing agent in the step (2) is 10-20 % of the mass of the biodiesel; and the extracting desulfurizing agent has the meaning in claim 1 or 2.

10. The desulfurizing refining method of biodiesel according to claim 8, wherein the method further comprises: after the step (2), repeating the operations in the step (1) and step (2) for 2-5 times, and determining a sulfur content of the biodiesel.