阅读说明：本技术 一种高熔点费托合成蜡的脱油方法 (Deoiling method of high-melting-point Fischer-Tropsch synthetic wax ) 是由 苗恒 钱震 王海国 袁玮 菅文应 韩飞 郭伟 周岩 王祯绮 于 2021-09-30 设计创作，主要内容包括：本发明提供了一种高熔点费托合成蜡的脱油方法,包括以下步骤：将熔点70℃以上的费托精制蜡在熔融状态下和蜡晶改性剂混合,得到混合物；所述蜡晶改性剂选自聚烯烃、聚(甲基)丙烯酸醋、富马酸二烷基-醋酸乙烯共聚物、苯乙烯-马来酸醋共聚物和萘的缩合物中的一种或多种；将所述混合物装料,降温结晶,升温发汗过程中离心脱油,收集,得到脱油后费托合成蜡。该方法一方面通过在原料蜡中加入上述种类的蜡晶改性剂,使原料蜡结晶时形成较大粒度蜡晶,利于后期“汗液”在较大蜡晶空隙中排出；另一方面,本方法发汗操作时采用离心设备,大大提高汗液排除效率和效果。(The invention provides a deoiling method of high-melting-point Fischer-Tropsch synthetic wax, which comprises the following steps: mixing Fischer-Tropsch refined wax with a melting point of more than 70 ℃ with a wax crystal modifier in a molten state to obtain a mixture; the wax crystal modifier is selected from one or more of polyolefin, poly (methyl) acrylic acid vinegar, fumaric acid dialkyl-vinyl acetate copolymer, styrene-maleic acid vinegar copolymer and naphthalene condensate; and (3) loading the mixture, cooling and crystallizing, centrifugally deoiling in the heating and sweating process, and collecting to obtain the deoiled Fischer-Tropsch synthetic wax. On one hand, the wax crystal modifier is added into the raw material wax, so that wax crystals with larger grain size are formed when the raw material wax is crystallized, and later-stage sweat can be discharged from gaps of the larger wax crystals; on the other hand, the method adopts centrifugal equipment during sweating operation, thereby greatly improving the efficiency and effect of removing sweat.)

1. A deoiling method for high-melting-point Fischer-Tropsch synthetic wax comprises the following steps:

mixing Fischer-Tropsch refined wax with a melting point of more than 70 ℃ with a wax crystal modifier in a molten state to obtain a mixture; the wax crystal modifier is selected from one or more of polyolefin, poly (methyl) acrylic acid vinegar, fumaric acid dialkyl-vinyl acetate copolymer, styrene-maleic acid vinegar copolymer and naphthalene condensate;

and (3) loading the mixture, cooling and crystallizing, centrifugally deoiling in the heating and sweating process, and collecting to obtain the deoiled Fischer-Tropsch synthetic wax.

2. The deoiling method of claim 1, wherein the wax crystal modifier accounts for 0.1-5 wt% of the mass of the Fischer-Tropsch refined wax with the melting point of above 70 ℃.

3. The deoiling method according to claim 1, wherein the specific process of temperature reduction and crystallization comprises:

cooling at a first cooling rate of 3-5 ℃/h, and keeping the temperature for 4-8 h for the first time when the temperature is reduced to 10-30 ℃ below the melting point;

continuously cooling at a second cooling rate, wherein the second cooling rate is higher than the first cooling rate, and continuously keeping the temperature for 4-8 hours for the second time when the temperature is reduced to 10-30 ℃ below the temperature of the first constant temperature;

and continuously cooling, wherein n sections are arranged in the cooling section, n is more than or equal to 2, and the cooling rate of the nth section is more than that of the nth-1 section until the cooling temperature is 40-70 ℃ below the melting point.

4. The deoiling method according to claim 1, wherein the specific process of warming and sweating comprises:

heating the wax crystal material obtained by cooling crystallization to a first temperature at a first heating rate of 0.5-10 ℃/h, and keeping the temperature for 4-8 h for the first time; the first temperature is 20-40 ℃ below the melting point;

continuing heating at a second heating rate, wherein the second heating rate is lower than the first heating rate, heating to a second temperature, and keeping the temperature constant for the second time; the second temperature is 10-20 ℃ higher than the first temperature;

and continuously heating, wherein m sections are arranged in the heating section, m is more than or equal to 3 and less than or equal to 5, and the heating rate of the mth section is less than that of the m-1 section until the temperature is raised to be higher than the melting point to melt the wax crystal material.

5. The deoiling method of claim 1, wherein the centrifugal deoiling is performed at a centrifugal speed of 3000rpm or more and for a centrifugal time of 10min or more.

6. The deoiling process of claim 1, wherein the fischer-tropsch refined wax having a melting point of 70 ℃ or higher is prepared according to the following process:

hydrofining and separating Fischer-Tropsch synthetic wax to obtain Fischer-Tropsch refined wax with the melting point of more than 70 ℃; the distillation range of the Fischer-Tropsch refined wax with the melting point of more than 70 ℃ is 50-100 ℃.

7. The deoiling process of claim 6, wherein the separating is carried out in a vacuum rectification column, a sidedraw vacuum rectification column, a vacuum rectification column bank, a thin film evaporator or a short path evaporator;

the pressure used for separation is more than 0Pa and less than or equal to 1000Pa, and the temperature is 150-350 ℃.

Technical Field

The invention belongs to the technical field of Fischer-Tropsch synthetic wax, and particularly relates to a deoiling method of high-melting-point Fischer-Tropsch synthetic wax.

Background

At present, the deep processing of the domestic Fischer-Tropsch synthetic wax is mainly carried out by related procedures such as hydrofining, separation and the like, and the refined wax is primarily separated into Fischer-Tropsch wax products with low melting points (less than 50 ℃), medium melting points (50-80 ℃), high melting points (more than 80-110 ℃) and other brands. Although the Fischer-Tropsch synthetic wax has high positive structuring degree, the Fischer-Tropsch synthetic wax still contains a small amount of oil components, and the Fischer-Tropsch wax products with various melting points which are cut out have high oil content still have a remarkable gap with foreign products, so that the Fischer-Tropsch synthetic wax cannot meet the requirements of high-end customers. Therefore, in order to obtain a high-end wax product meeting the product indexes at home and abroad, the Fischer-Tropsch synthesis crude wax or the cut fraction wax needs to be deoiled.

There are two main types of deoiling processes widely used globally for producing fully (semi) refined paraffin, including sweating deoiling and solvent deoiling, and fractional crystallization deoiling technology is also a process derived on the basis of sweating.

The solvent deoiling technology separates oil from wax by utilizing different solubilities of the solvent to the oil and the wax, but the solvent deoiling technology mainly has the problems that a large amount of solvent is needed in the production process, the solvent needs to be recovered with large energy consumption and the like, the solvent is flammable and easily causes production accidents, and meanwhile, the solvent can also affect the environment.

The sweating deoiling method is to separate and purify various hydrocarbon components in wax by utilizing the property of different melting points.

The common sweating deoiling process mainly comprises the following steps: (1) preparation work: filling water, and filling the lower space of the sweating device with water; (2) charging: heating the raw materials to a temperature above the melting point and putting the raw materials into a sweating device when the raw materials are in a liquid state; (3) cooling and crystallizing: during the cooling process, the components are crystallized from high to low in the order of melting point to form a solid. (4) Warming and sweating: when the temperature of the wax layer reaches the specified temperature and crystallization is completed, draining the padding water; the raw materials are slowly heated to the temperature required for sweating according to a temperature control program. During the heating and sweating process, the components are sequentially melted into liquid state according to the sequence of melting point from low to high and flow out of the wax, and finally the wax layer residue is obtained, namely the wax with high melting point and low oil content is on the wax. (5) Collecting products: and after the temperature rise and sweating are finished, the temperature is continuously raised to melt and take out the wax, and the product is obtained.

In the common sweating and deoiling method, the solid component wax with a higher melting point, the wax with a lower melting point and the liquid component oil are respectively in two phases of solid and liquid in the temperature rising and sweating process, but the two components are difficult to be completely separated. In order to meet the oil content of the final product, methods of prolonging the sweating time and raising the sweating termination temperature are generally used, but this results in long production cycles and a decrease in product yield.

Disclosure of Invention

In view of the above, the present invention aims to provide a method for deoiling a high melting point fischer-tropsch wax, which has a high deoiling effect.

The invention provides a deoiling method of high-melting-point Fischer-Tropsch synthetic wax, which comprises the following steps:

mixing Fischer-Tropsch refined wax with a melting point of more than 70 ℃ with a wax crystal modifier in a molten state to obtain a mixture; the wax crystal modifier is selected from one or more of polyolefin, poly (methyl) acrylic acid vinegar, fumaric acid dialkyl-vinyl acetate copolymer, styrene-maleic acid vinegar copolymer and naphthalene condensate;

and (3) loading the mixture, cooling and crystallizing, centrifugally deoiling in the heating and sweating process, and collecting to obtain the deoiled Fischer-Tropsch synthetic wax.

The wax crystal modifier accounts for 0.1-5 wt% of the mass of the Fischer-Tropsch refined wax with the melting point of more than 70 ℃.

In the invention, the wax crystal modifier can change the crystal form of the high-melting-point Fischer-Tropsch wax with the temperature of more than 70 ℃, and simultaneously, in order to improve the sweat discharge efficiency and the sweat discharge effect, a centrifugal device is used as a sweating device, so that the deoiling efficiency is improved, the product yield of common sweating is improved, and the deoiling of the high-melting-point Fischer-Tropsch wax is realized.

In the invention, the melting point of the Fischer-Tropsch refined wax with the melting point of more than 70 ℃ is 78 ℃, and the oil content is 2.6%; or the melting point is 91 ℃ and the oil content is 0.9 percent.

In the invention, the specific process of temperature-reducing crystallization comprises the following steps:

cooling at a first cooling rate of 3-5 ℃/h, and keeping the temperature for 4-8 h for the first time when the temperature is reduced to 10-30 ℃ below the melting point;

continuously cooling at a second cooling rate, wherein the second cooling rate is higher than the first cooling rate, and continuously keeping the temperature for 4-8 hours for the second time when the temperature is reduced to 10-30 ℃ below the temperature of the first constant temperature;

and continuously cooling, wherein n sections are arranged in the cooling section, n is more than or equal to 2, and the cooling rate of the nth section is more than that of the nth-1 section until the cooling temperature is 40-70 ℃ below the melting point.

In the invention, the specific process of warming and sweating comprises the following steps:

heating the wax crystal material obtained by cooling crystallization to a first temperature at a first heating rate of 0.5-10 ℃/h, and keeping the temperature for 4-8 h for the first time; the first temperature is 20-40 ℃ below the melting point;

continuing to heat at a second heating rate, wherein the second heating rate is lower than the first heating rate, heating to a second temperature, and continuing to perform constant temperature for the second time;

and continuously heating, wherein m sections are arranged in the heating section, m is more than or equal to 3 and less than or equal to 5, and the heating rate of the mth section is less than that of the m-1 section until the temperature is raised to be higher than the melting point to melt the wax crystal material.

In the invention, the termination temperature of the third temperature rise is preferably 5-10 ℃ higher than that of the second temperature rise; the termination point of the fourth temperature rising section is 1-5 ℃ higher than that of the third temperature rising section, and the fifth temperature rising section melts the raw materials above the melting point and discharges the raw materials.

The temperature is kept constant after the temperature is raised to a certain temperature each time; the constant temperature time is preferably 4-8 h.

In the invention, the centrifugal rotation speed of the centrifugal deoiling is more than or equal to 3000rpm, and the centrifugal time is more than or equal to 10 min. The bottom of the traditional sweating device, such as a vertical tubular heat exchanger, needs to be padded with water to prevent molten wax from entering the sweating deoiling device to block a support plate (with pores, and subsequent sweat is discharged at the bottom by gravity or other external force). The invention adopts the centrifugal oil removal in the centrifugal sweating device, and the sweat is thrown out in a centrifugal mode, and the sweat of light components is discharged at the upper part, so that the bottom is not padded with water. The centrifugal deoiling device is not limited to the model, has a centrifugal function, and is equipped with the program temperature control function according to the demand.

In the invention, the Fischer-Tropsch refined wax with the melting point of more than 70 ℃ is prepared by the following method:

hydrofining and separating Fischer-Tropsch synthetic wax to obtain Fischer-Tropsch refined wax with the melting point of more than 70 ℃; the distillation range of the Fischer-Tropsch refined wax with the melting point of more than 70 ℃ is 50-100 ℃.

In the present invention, the separation is carried out in a vacuum rectification column, a vacuum rectification column with a side line, a vacuum rectification column group, a thin film evaporator or a short path evaporator;

the pressure used for separation is more than 0Pa and less than or equal to 1000Pa, and the temperature is 150-350 ℃.

The invention uses standard SH/T0638 to detect the oil content in wax.

The invention provides a deoiling method of high-melting-point Fischer-Tropsch synthetic wax, which comprises the following steps: mixing Fischer-Tropsch refined wax with a melting point of more than 70 ℃ with a wax crystal modifier in a molten state to obtain a mixture; the wax crystal modifier is selected from one or more of polyolefin, poly (methyl) acrylic acid vinegar, fumaric acid dialkyl-vinyl acetate copolymer, styrene-maleic acid vinegar copolymer and naphthalene condensate; and (3) loading the mixture, cooling and crystallizing, centrifugally deoiling in the heating and sweating process, and collecting to obtain the deoiled Fischer-Tropsch synthetic wax. On one hand, the wax crystal modifier is added into the raw material wax, so that wax crystals with larger grain size are formed when the raw material wax is crystallized, and later-stage sweat can be discharged from gaps of the larger wax crystals; on the other hand, the method adopts centrifugal equipment during sweating operation, thereby greatly improving the efficiency and effect of removing sweat.

Detailed Description

In order to further illustrate the present invention, the method for deoiling a high melting point fischer-tropsch wax provided by the present invention is described in detail with reference to the following examples, which should not be construed as limiting the scope of the present invention.

Example 1

The Fischer-Tropsch wax is prepared from Fischer-Tropsch wax obtained by a certain Fischer-Tropsch synthesis process as a raw material through a hydrofining reaction.

The Fischer-Tropsch refined wax sequentially enters a thin film evaporator and a short-path evaporator for separation to obtain the Fischer-Tropsch fraction wax with the distillation range of 70 ℃ and the melting point of 78 ℃.

The Fischer-Tropsch wax with the melting point of 78 ℃ contains 2.6 wt% of oil, 0.5% of wax crystal modifier poly (methyl) acrylic acid vinegar is added into the molten state, and the mixture is fully mixed and then added into a sweat tube of a centrifugal sweating device. Slowly cooling by a temperature control system of a centrifugal sweating device at a cooling rate of 3 ℃/h to 50 ℃, and keeping the temperature for 4 h; the temperature is reduced to 30 ℃ at the rate of 5 ℃/h, and the temperature is kept for 4 h. Cooling to 10 ℃ at a cooling rate of 5 ℃/h, and keeping the temperature for 4h to finish the cooling and crystallizing process. Slowly heating to 50 ℃ at the heating rate of 5 ℃/h, keeping the temperature for 4h, performing centrifugal deoiling for 10min, and collecting sweat; continuously and slowly heating to 65 ℃ at the heating rate of 3 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, and collecting sweat; continuously and slowly heating to 70 ℃ at the heating rate of 2 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, and collecting sweat; heating to 75 ℃ at the heating rate of 1 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, collecting sweat, and finishing the sweating process. And finally, heating to the temperature of more than 80 ℃, melting and collecting a sample, wherein the product yield is 71%.

The product was analyzed: melting point is 80.1 deg.C, and oil content is 0.7%.

Control group: for the 78 ℃ raw material wax, no wax crystal modifier is added, the operation is carried out in a traditional vertical type tube array sweating device, under the same operation steps (namely the same temperature rise and fall control program, no centrifugal deoiling operation), the product yield is 48%, and the product analysis is as follows: melting point 79.3 ℃ and oil content 1.8 wt%.

Example 2:

the Fischer-Tropsch wax is prepared from Fischer-Tropsch wax obtained by a certain Fischer-Tropsch synthesis process as a raw material through a hydrofining reaction.

The Fischer-Tropsch refined wax sequentially enters a thin film evaporator and a short-path evaporator for separation to obtain the Fischer-Tropsch fraction wax with the distillation range of 50 ℃ and the melting point of 91 ℃.

The Fischer-Tropsch fraction wax with the melting point of 91 ℃ contains 0.9 wt% of oil, 2% of wax crystal modifier styrene-maleic acid-vinegar copolymer is added in the molten state, and the mixture is fully mixed and then added into a sweat tube of a centrifugal sweat device. Slowly cooling by a temperature control system of a centrifugal sweating device at a cooling rate of 3 ℃/h to 70 ℃, and keeping the temperature for 2 h; the temperature is reduced to 50 ℃ at the rate of 3 ℃/h and the temperature is kept for 4 h. Cooling to 30 ℃ at a cooling rate of 5 ℃/h, and keeping the temperature for 4h to finish the cooling and crystallizing process. Slowly heating to 60 ℃ at the heating rate of 8 ℃/h, keeping the temperature for 4h, performing centrifugal deoiling for 10min, and collecting sweat; continuously and slowly heating to 75 ℃ at the heating rate of 5 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, and collecting sweat; continuously and slowly heating to 80 ℃ at the heating rate of 3 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, and collecting sweat; heating to 85 ℃ at the heating rate of 1 ℃/h, keeping the temperature for 4h, carrying out centrifugal deoiling for 10min, collecting sweat, and finishing the sweating process. And finally, heating to more than 100 ℃, melting and collecting a sample, wherein the product yield is 83%.

The product was analyzed: the melting point was 92.9 ℃ and the oil content was 0.3 wt.%.

From the above embodiments, it can be seen that in the method provided by the present invention, for the high melting point fischer-tropsch wax with a melting point higher than 70 ℃, the wax is crystallized by adding the wax crystal modifier, and the wax grows into crystals with coarse and uniform particle size when being cooled, and the crystallized wax layer is porous and easy to permeate, so as to finally achieve the effects of easy sweat discharge and improved deoiling; on the other hand, the centrifugal device is adopted for sweating operation, so that the sweat discharge efficiency and the sweat discharge effect are improved.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.