阅读说明：本技术 一种精制中温沥青的制备方法 (Preparation method of refined medium-temperature asphalt ) 是由 刘春法 刘其国 于 2020-05-07 设计创作，主要内容包括：本发明涉及一种精制中温沥青的制备方法,其包括如下步骤：将煤焦油在120～170℃进行离心,得到净化焦油轻相；将所述净化焦油轻相进行蒸馏,得到中温沥青；将所述中温沥青在230～270℃下进行程序过滤,得到所述精制中温沥青；其中,所述净化焦油轻相中的QI含量为0～0.3％,所述馏分中的QI含量为0～0.6％,软化点为70～85℃。本发明具有以下有益效果：1)传统的方法是焦油蒸馏得到的中温沥青采用溶剂沉降法、离心分离法、闪蒸分离法,采用碟片式离心机和桶式过滤器的方法,工艺更加简单,QI含量控制更加稳定；2)通过本发明的制备方法得到的精制中温沥青的QI含量≤0.03％,软化点为70～85℃。(The invention relates to a preparation method of refined medium-temperature asphalt, which comprises the following steps: centrifuging the coal tar at 120-170 ℃ to obtain a purified tar light phase; distilling the purified tar light phase to obtain medium temperature pitch; performing program filtration on the medium-temperature asphalt at 230-270 ℃ to obtain refined medium-temperature asphalt; wherein the QI content in the purified tar light phase is 0-0.3%, the QI content in the fraction is 0-0.6%, and the softening point is 70-85 ℃. The invention has the following beneficial effects: 1) the traditional method is that medium temperature pitch obtained by tar distillation adopts a solvent sedimentation method, a centrifugal separation method and a flash separation method, and adopts a disc centrifuge and a barrel filter method, so that the process is simpler, and the QI content is more stably controlled; 2) the QI content of the refined medium-temperature asphalt obtained by the preparation method is less than or equal to 0.03%, and the softening point is 70-85 ℃.)

1. A preparation method of refined medium-temperature asphalt is characterized by comprising the following steps:

performing centrifugal separation on the coal tar at 120-170 ℃ to obtain a purified tar light phase and a purified tar slag phase;

carrying out reduced pressure distillation on the purified tar light phase to obtain medium temperature pitch;

performing program filtration on the medium-temperature asphalt at 230-270 ℃ to obtain refined medium-temperature asphalt;

wherein the QI content in the purified tar light phase is 0-0.3%, the QI content in the medium-temperature asphalt is 0-0.6%, and the softening point is 70-85 ℃.

2. The method for preparing refined medium-temperature asphalt according to claim 1, wherein the centrifugation is performed in a disk-type centrifuge.

3. The process for preparing refined medium-temperature asphalt according to claim 1, wherein the operation of said programmed filtration is carried out in a rod filter.

4. The process for producing refined medium-temperature asphalt according to claim 1, wherein the temperature of the reduced pressure distillation is 240 to 380 ℃ and the absolute pressure is 1 to 40 KPa.

Technical Field

The invention relates to a preparation method of refined medium-temperature asphalt, belonging to the technical field of coal chemical industry.

Background

Coal tar pitch is a bulk product of deep processing of coal tar, and accounts for more than 50% of the total amount of the coal tar, China is a large country for producing and applying the coal tar pitch, and the yield of the coal tar pitch is more than 200 million tons at present. Therefore, the deep processing and application of the coal pitch have profound significance for the development of coal chemical industry.

Coal tar pitch is a complex mixture of many high molecular weight aromatic compounds, and pitch is not completely soluble in any known solvent so far, so that it is generally difficult to extract a single substance with a certain chemical composition and structure from the mixture, and only the substance is extracted by various solvents and divided into a plurality of components for research. Due to different research purposes, different solvents and different operation methods, coal tar pitch has various grouping methods. Of these, the separation into, and the three components are more common. The grouping method is shown in fig. 1.

In which the role of Quinoline Insoluble (QI) component is more and more emphasized, and low-QI asphalt is required for raw materials such as needle coke, spinning asphalt, high-thermal conductivity foam carbon and the like.

Chinese patent CN1058984 discloses a method for separating quinoline insoluble substances in coal tar by a centrifugal method, wherein the content of quinoline insoluble substances in the coal tar obtained by the method is less than or equal to 0.08 percent under the conditions that the separation temperature is 75-90 ℃ and the revolution of a centrifugal machine is 6500-7500 r/min, the yield of purified coal tar is 80 percent, and the method is suitable for the coal tar and is not suitable for pitch with higher viscosity.

The U.S. Pat. No. 4, 4986895 discloses a technology for obtaining refined soft pitch by 'primary centrifugation-pressurized thermal polycondensation-secondary centrifugation' starting from coal tar. Separating primary quinoline insoluble substances in coal tar, wherein the temperature of primary centrifugation is 200-350 ℃, and the separation factor is 2000-3500G; the temperature of the pressurized thermal polycondensation is 350-450 ℃, and the pressure is less than 2 MPa; in order to separate the secondary quinoline insoluble substances generated in the thermal polycondensation process of the coal tar, the secondary centrifugation operation temperature is 200-400 ℃, and the separation factor is 2000-4000G.

In order to achieve a good QI removal effect, the above U.S. patent requires to operate at a higher temperature, so that the performance requirements on the centrifuge are severe, and the general centrifuge is limited by the requirements of materials, sealing materials and the like, and the allowable operating temperature is less than or equal to 100 ℃.

Chinese patent CN1793287A discloses a process for purifying maltha by solvent static settling, wherein the adopted solvent is a mixed solvent of aliphatic hydrocarbon and aromatic hydrocarbon 0.6-1.2: 1, the mixed solvent and maltha are fully stirred and mixed in a stirring kettle according to the proportion of 0.6-1.6: 1 at the temperature of 90-120 ℃, after standing and settling for 2-20 hr, the upper layer light phase is sent to a solvent recovery tower to recover the solvent to obtain purified asphalt, and the lower layer heavy phase is distilled to recover the solvent to obtain binder asphalt. The technology is used for large-scale industrial production, and the required settling tank has large volume, large quantity, large occupied area, intermittent operation, frequent operation and low efficiency.

Chinese patent CN101302431A adopts a centrifugal filtration method to remove QI in coal tar or coal pitch. Firstly adding the coal tar light component containing the filter aid into a centrifuge to form a uniform filter aid filter cake, then introducing a mixed solution of the coal tar or the coal pitch added with the washing oil and the filter aid into the centrifuge which forms the uniform filter cake for separation, and recovering the solvent from the centrifuged solution through atmospheric distillation to obtain the purified maltha with the QI content of 0.22-0.27%. The method is intermittent operation, has high labor intensity and serious pollution when replacing the filter cloth, and is not suitable for industrial large-scale production. In addition, the QI content of the purified maltha is higher than the level of 0.1% or less suggested in the general literature.

Disclosure of Invention

The invention provides coal-based refined medium-temperature asphalt with more stable quality, wherein the QI content is less than or equal to 0.03%, and the softening point is 70-85 ℃, so that the problems in the prior art are solved.

The invention is realized by the following technical scheme:

the invention provides a preparation method of refined medium-temperature asphalt, which comprises the following steps:

performing centrifugal separation on the coal tar at 120-170 ℃ to obtain a purified tar light phase and a purified tar slag phase;

carrying out reduced pressure distillation on the purified tar light phase to obtain medium temperature pitch;

performing program filtration on the medium-temperature asphalt at 230-270 ℃ to obtain refined medium-temperature asphalt;

wherein the QI content in the purified tar light phase is 0-0.3%, the QI content in the medium-temperature asphalt is 0-0.6%, and the softening point is 70-85 ℃. The light phase of the purified tar can remove more than 50 percent of light components through reduced pressure distillation, and QI is about 2 times of the content of the purified tar in the heavy phase medium temperature asphalt.

Preferably, the centrifugation is performed in a disk centrifuge.

Preferably, the temperature of the reduced pressure distillation is 240-380 ℃, and the absolute pressure is 1-40 KPa.

Preferably, the operation of the programmed filtration is carried out in a rod filter. The procedure for the rod filter includes: in the filter cake forming process, after a certain filter cake is formed, refined medium-temperature asphalt with the QI content of less than or equal to 0.03 percent can be obtained, and the filter efficiency is reduced along with the thickening of the filter cake, so that the filter rods need to be subjected to the processes of backwashing, regeneration and the like.

The invention has the following beneficial effects:

1) the traditional method is that medium temperature pitch obtained by tar distillation adopts a solvent sedimentation method, a centrifugal separation method and a flash separation method, and adopts a disc centrifuge and a barrel filter method, so that the process is simpler, and the QI content is more stably controlled;

2) the purification cost is greatly reduced, a solvent settling method, a centrifugal separation method and a flash separation method all use a mixed solvent, the volatilization amount of the mixed solvent is large, the solvent must be removed by flash evaporation through a flash tower after separation, a large amount of energy consumption is consumed, the solvent is unstable, and the quality of refined asphalt is unstable;

3) the QI content of the refined medium-temperature asphalt obtained by the preparation method is less than or equal to 0.03%, and the softening point is 70-85 ℃.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

FIG. 1 is a schematic diagram of the analysis flow of the solvent extraction components of coal pitch;

FIG. 2 is a process flow chart of the process for producing refined medium-temperature asphalt according to the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the present invention.

Example 1

The embodiment relates to a preparation method of refined medium-temperature asphalt, as shown in fig. 2, which specifically comprises the following steps:

coal tar with the QI content of 3.6% is adopted, and is centrifuged at 156 ℃ by a disc centrifuge to obtain the coal tar with the QI content of 0.2%; the obtained coal tar is subjected to reduced pressure distillation to obtain medium temperature pitch with QI content of 0.36% and softening point of 75 ℃. Medium temperature asphalt with QI content of 0.36% and softening point of 75 deg.C was subjected to drum filter procedure at 265 deg.C to obtain refined medium temperature asphalt with QI content of 0.02% and softening point of 73.5 deg.C.

Example 2

The embodiment relates to a preparation method of refined medium-temperature asphalt, which specifically comprises the following steps:

coal tar with QI content of 2.6% is adopted, and is centrifuged at 145 ℃ by a disc centrifuge to obtain coal tar with QI content of 0.15%; the obtained coal tar is distilled under reduced pressure to obtain medium temperature pitch with QI content of 0.33% and softening point of 81 ℃. Medium temperature asphalt with QI content of 0.33% and softening point of 81 deg.C was subjected to drum filter procedure at 251 deg.C to obtain refined medium temperature asphalt with QI content of 0.01% and softening point of 76.9 deg.C.

In summary, the present invention is only a preferred embodiment, and not intended to limit the scope of the invention, and all equivalent changes and modifications in the shape, structure, characteristics and spirit of the present invention described in the claims should be included in the scope of the present invention.