阅读说明：本技术 一种采用离子液体作为萃取剂的汽油脱硫方法 (Gasoline desulfurization method adopting ionic liquid as extractant ) 是由 方静 安志伟 李�浩 李春利 于 2019-10-21 设计创作，主要内容包括：本发明为一种采用离子液体作为萃取剂的汽油脱硫方法。该方法包括以下步骤：将离子液体在常温下由第10-30块板注入萃取塔内,含硫汽油在常温下由第5-10块板进入,塔顶采出液为质量分数大于99％的正辛烷；萃取塔塔釜采出离子液体和噻吩类衍生物的混合物,质量比为离子液体：含硫汽油＝1:0.7-1；所述的离子液体阴离子种类为磷酸根、硼酸根、氯酸根、醋酸根或磺酰基酰亚胺类；阳离子种类为吡啶类阳离子、季铵盐类阳离子或咪唑类阳离子。本发明采用离子液体作为萃取剂来脱除燃油中的噻吩类化合物,来达到对汽油进行高效脱硫的目的,为工业实施提供了可能。(The invention relates to a gasoline desulfurization method using ionic liquid as an extractant. The method comprises the following steps: injecting ionic liquid into the extraction tower from the 10 th to 30 th plates at normal temperature, introducing sulfur-containing gasoline from the 5 th to 10 th plates at normal temperature, and taking produced liquid at the tower top as n-octane with the mass fraction of more than 99%; the mixture of the ionic liquid and the thiophene derivative is extracted from the tower bottom of the extraction tower, and the mass ratio of the ionic liquid to the thiophene derivative is as follows: sulfur-containing gasoline 1: 0.7-1; the ionic liquid anion species are phosphate radicals, borate radicals, chlorate radicals, acetate radicals or sulfonyl imide species; the cation type is pyridine cations, quaternary ammonium salt cations or imidazole cations. The invention adopts the ionic liquid as the extracting agent to remove the thiophene compounds in the fuel oil, achieves the aim of efficiently desulfurizing the gasoline, and provides possibility for industrial implementation.)

1. A gasoline desulfurization method using ionic liquid as an extractant is characterized by comprising the following steps:

injecting ionic liquid into the extraction tower from the 10 th to 30 th plates at normal temperature, introducing sulfur-containing gasoline from the 5 th to 10 th plates at normal temperature, and taking produced liquid at the tower top as n-octane with the mass fraction of more than 99%; the mixture of the ionic liquid and the thiophene derivative is extracted from the tower bottom of the extraction tower, and the mass ratio of the ionic liquid to the thiophene derivative is as follows: sulfur-containing gasoline =1: 0.7-1;

wherein the number of tower plates of the extraction tower is 10 ~ 30, the operating pressure is 101.325Kpa, the temperature of the extraction tower is 28 ~ 33 ℃, the mass ratio of ionic liquid to sulfur ~ containing gasoline is =1:0.7 ~ 1, the number of tower plates of the extraction tower is 10 ~ 30, the operating pressure is 101.325Kpa, and the reflux ratio of the tower top is 1.5 ~ 2.5;

The ionic liquid anion species are phosphate radicals, borate radicals, chlorate radicals, acetate radicals or sulfonyl imide species; the cation type is pyridine cations, quaternary ammonium salt cations or imidazole cations;

The sulfur-containing gasoline contains 1-5% of sulfur element by mass.

2. The method for desulfurizing gasoline using an ionic liquid as an extractant according to claim 1, wherein the ionic liquid is selected from the group consisting of 1-hexyl-3-methylimidazole trifluorophosphate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole hexafluorophosphate, 1-octyl-3-methylimidazole chloride, 1-ethyl-3-methylimidazole acetate and 1-ethyl-3-methylimidazole ethoxy sulfonate.

3. The method of claim 1, wherein the sulfur-containing gasoline component comprises n-octane and thiophene derivatives; the mass ratio is preferably n-octane: the thiophene derivatives are 30: 1.

4. A gasoline desulfurization method using ionic liquid as an extractant according to claim 3, characterized in that the thiophene derivatives are preferably benzothiophenes.

Technical Field

The invention relates to the field of extraction, in particular to an ionic liquid for separating gasoline desulfurization substances by adopting an extraction tower and an extraction method.

background

Thiophene sulfides account for more than 70 percent of the total sulfur content in catalytic cracked gasoline (FCC); the content of thiophene sulfides in the diesel oil is more than 85 percent of the total sulfur content. Therefore, the removal of thiophene sulfides is the key to reducing the sulfur content of fuel.

Currently, the commonly used fuel oil desulfurization techniques can be mainly classified into two categories: hydrodesulfurization technology (HDS) and non-hydrodesulfurization technology (NHDS). The hydrodesulfurization technology is the most widely applied fuel oil desulfurization method in the petroleum refining industry, is mature, has a good removal effect on most sulfides in fuel oil, such as mercaptan, thioether and the like, but has a non-ideal deep desulfurization effect, can reduce the contents of olefin and aromatic hydrocarbon in the fuel oil, causes the reduction of the octane number of the fuel oil, and has the defects of high investment and operation cost, harsh operation conditions and the like. Desulfurization technologies widely studied at present, such as adsorption desulfurization technology, biological desulfurization technology, oxidative desulfurization technology, extraction desulfurization technology, and the like, are collectively referred to as non-hydrodesulfurization technologies. However, the adsorptive desulfurization method has low selectivity and difficult adsorbent regeneration; the biological desulfurization method has low desulfurization speed, and oil and water phases are not easy to separate; the oxidative desulfurization method has high investment cost, low fuel yield and difficult treatment of sulfur-containing compounds.

The extraction desulfurization operation condition is mild (low temperature, low pressure or normal temperature and normal pressure), the properties of the desulfurized oil product are not changed, extra substances such as hydrogen, oxidant and the like are not required to be consumed, the equipment is simple, the flow is short, and the investment cost is low. However, the desulfurization rate of the method is low due to the limitation of the property of the extracting agent, and the environmental pollution caused by the traditional organic solvent extraction is serious.

Currently, the extracting agent used in the extraction desulfurization technology is generally methanol solution, a compound solvent of TS-1 complex extracting agent N, N-dimethylformamide and acetonitrile, and N-formylmorpholine, and the extracting agents have the limitations of low single desulfurization rate, secondary pollution, poor repeatability and the like. Therefore, the development of an efficient and low-pollution green extraction desulfurization solvent is the research focus of the current extraction desulfurization process.

disclosure of Invention

The invention aims to provide a gasoline desulfurization method adopting ionic liquid as an extractant, aiming at the defects that the traditional desulfurization method can not achieve deep desulfurization, has high operation cost, large investment, harsh reaction conditions and the use of harmful volatile solvents. The method adopts the ionic liquid as the extracting agent to remove the thiophene compounds in the fuel oil, achieves the aim of efficiently desulfurizing the gasoline, and provides possibility for industrial implementation.

The technical scheme of the invention is as follows:

A gasoline desulfurization method adopting ionic liquid as an extractant comprises the following steps:

Injecting ionic liquid into the extraction tower from the 10 th to 30 th plates at normal temperature, introducing sulfur-containing gasoline from the 5 th to 10 th plates at normal temperature, and taking produced liquid at the tower top as n-octane with the mass fraction of more than 99%; the mixture of the ionic liquid and the thiophene derivative is extracted from the tower bottom of the extraction tower, and the mass ratio of the ionic liquid to the thiophene derivative is as follows: sulfur-containing gasoline 1: 0.7-1;

Wherein the number of the tower plates of the extraction tower is 10-30, and the operating pressure is 101.325 Kpa; the temperature of the extraction tower is 28-33 ℃; the mass ratio of the ionic liquid: sulfur-containing gasoline is 1:0.7-1, the number of tower plates of the extraction tower is 10-30, and the operation pressure is 101.325 Kpa; the reflux ratio of the tower top is 1.5-2.5;

The ionic liquid anion species are phosphate radicals, borate radicals, chlorate radicals, acetate radicals or sulfonyl imide species; the cation type is pyridine cations, quaternary ammonium salt cations or imidazole cations; specifically 1-hexyl-3-methylimidazole trifluorophosphate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole hexafluorophosphate, 1-octyl-3-methylimidazole chloride, 1-ethyl-3-methylimidazole acetate or 1-ethyl-3-methylimidazole ethoxy sulfonate.

The sulfur-containing gasoline contains 1 to 5 percent of sulfur element by mass;

the sulfur-containing gasoline comprises the following components: thiophene derivatives; the mass ratio is preferably n-octane: the thiophene derivatives are 30: 1.

The thiophene derivative is benzothiophene.

the invention has the beneficial effects that:

the invention uses the extraction gasoline desulfurization tower and adopts the ionic liquid as the extractant to achieve the purpose of desulfurizing the gasoline, thereby providing possibility for industrial implementation. The prior art is limited by the property of an extracting agent, the desulfurization rate of the method is low, the desulfurization rate is about 80 percent, the pollution of the traditional organic solvent to the environment is serious, and the ionic liquid is a high-efficiency and low-pollution green extraction desulfurization solvent. The ionic liquid can improve the extraction desulfurization rate in an n-octane-benzothiophene mixed system, and the application example shows that when the mass ratio of the ionic liquid to gasoline is 1:0.7, the ionic liquid can be well extracted to obtain more than 99% of n-octane and benzothiophene. For an n-octane-benzothiophene system, the ionic liquid and the benzothiophene have good intersolubility, and the relative volatility of n-octane relative to the benzothiophene can be improved through the action of chemical affinity, hydrogen bond force and the like and water. If in view of polarity, the n-octane is a non-polar solvent, the benzothiophene is a polar solvent, the ionic liquid has strong polarity, and the interaction between the ionic liquid and the benzothiophene molecules is far greater than that between the ionic liquid and the n-octane molecules, so that the relative volatility of the n-octane is improved.

Drawings

FIG. 1: the invention relates to a flow diagram of extraction gasoline desulfurization.

Wherein the central equipment is an extraction tower, 1 is an ionic liquid stream, 2 is an n-octane raffinate phase stream extracted from the top of the tower, 3 is an n-octane-benzothiophene mixture (gasoline model compound) feeding stream, and 4 is a tower bottom ionic liquid-benzothiophene extract phase stream

Detailed Description

The present invention is described in detail below with reference to fig. 1, which is for illustrative purposes only and is not intended to be limiting.

The gasoline containing 1% of sulfur element in percentage by mass comprises two components in percentage by mass: the thiophene sulfur-containing compound is 30: 1

The method for desulfurizing the extraction separation gasoline provided by the invention comprises the following steps in detail:

the actual plate number of the extraction tower is 30, the operation pressure is 101.325Kpa, the ionic liquid (normal temperature 20-30 ℃) enters from the 20 th plate, the n-octane-benzothiophene mixture enters from the 5 th plate at normal temperature (20-30 ℃), the produced liquid at the tower top is n-octane with the mass fraction of 99.2-99.4%, and the reflux ratio is 2; extracting a mixture of ionic liquid and benzothiophene from the tower kettle of the extraction tower; the temperature of the extraction tower is 25-30 ℃; wherein the mass ratio is that the ionic liquid: n-octane-benzothiophene mixture ═ 1: 0.7-1.

The ionic liquid is specifically 1-hexyl-3-methylimidazole trifluorophosphate, 1-butyl-3-methylimidazole tetrafluoroborate, 1-butyl-3-methylimidazole hexafluorophosphate, 1-octyl-3-methylimidazole chloride, 1-ethyl-3-methylimidazole acetate or 1-ethyl-3-methylimidazole ethoxy sulfonate, which are all commercially known substances and have analytical purity.

the extraction tower related by the invention is a common plate tower, and the diameter of the tower is 1 m.