Method for preparing an impregnating agent with zero quinoline insoluble content

Abstract

The invention relates to a method for preparing an impregnating agent asphalt, and in particular to a method for preparing an impregnating agent with zero quinoline insoluble matter content. The problem to be solved is to provide an impregnating agent asphalt with zero quinoline insoluble matter content, which is prepared by using ethylene tar as a raw material and controlling the composition, thermal polymerization and air oxidation conditions of the ethylene tar. The technical scheme adopted is as follows: heating the ethylene tar, and then using a ceramic plate filter to remove quinoline insoluble matter and ash from the ethylene tar; conveying the ethylene tar from which the quinoline insoluble matter and ash have been removed to a first autoclave stirred reactor, heating the ethylene tar and separating light components therein by vacuuming to obtain heavy tar; conveying part of the heavy tar to a second autoclave stirred reactor, introducing air to obtain medium-temperature petroleum asphalt; conveying the medium-temperature petroleum asphalt to a third autoclave stirred reactor, and simultaneously adding part of the heavy tar to the third autoclave stirred reactor, and stirring and mixing the two for reaction.

Description

Technical Field

[0001] The present invention relates to a method for preparing an impregnating agent asphalt, in particular to a method for preparing an impregnating agent with zero quinoline insoluble matter content. Background Art

[0002] With the continuous development of the steel industry, the performance requirements for graphite electrodes are becoming increasingly stringent. Graphite electrodes are primarily made from natural graphite (or needle coke), binder pitch, and impregnating pitch. They are formed and then gradually heat-treated at high temperatures. The impregnating pitch fills the pores created during the forming and heat-treatment processes, reducing the active sites in the graphite electrode and thereby extending its service life. Therefore, the effectiveness and frequency of impregnation with the impregnating pitch significantly impact the production cost and service life of the graphite electrode.

[0003] Currently, there are two main methods for producing impregnating pitch in China. One uses medium-temperature coal tar pitch as the raw material and removes some quinoline-insoluble matter (QI) through centrifugation or filtration. Because medium-temperature coal tar pitch itself contains 5-9% QI, the QI content of the impregnating pitch produced by this method is typically 2-3.5%. The other method uses coal tar as the raw material, removes the QI components through a mixture of wash oil and kerosene, and then undergoes moderate thermal polymerization to produce a low-QI impregnating pitch. In theory, increasing the sedimentation ratio can significantly reduce the QI content of the impregnating pitch, but this increases production costs. Therefore, the QI content of the impregnating pitch produced by this method is typically 1-1.5%. The QI content of the impregnating pitch directly affects the impregnation quality and the number of impregnations required for graphite electrodes. Therefore, domestic graphite electrode manufacturers generally require the electrodes to be impregnated three to four times, which undoubtedly increases production costs. Therefore, how to adopt a new approach to prepare impregnating asphalt with 0% quinoline insoluble matter is an asphalt variety urgently needed by the domestic carbon industry.

[0004] Ethylene tar, a byproduct of ethylene production, boasts a domestic production of 1.8 million tons per year. Currently, ethylene tar is primarily used as a feedstock for fuel oil or industrial carbon black, with minimal added value. Developing a high-value-added ethylene tar solution is a major challenge facing the petrochemical industry. Summary of the Invention

[0005] The present invention overcomes the shortcomings of the existing technology and provides a method for preparing an impregnant with zero quinoline-insoluble content. This method addresses the current performance status of domestic impregnant pitches and the background of ethylene tar. Using ethylene tar as a raw material, the method controls the composition, thermal polymerization, and air oxidation conditions of the ethylene tar to produce an impregnant pitch with zero quinoline-insoluble content. This method not only effectively reduces the production cost of graphite electrodes but also provides a path to increasing the added value of ethylene tar.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A method for preparing an impregnating agent with zero quinoline insoluble content comprises the following steps:

[0008] 1) Ethylene tar is heated to 80-150°C in a tubular reactor and then flows into a ceramic plate filter to remove quinoline insoluble matter and ash from the ethylene tar;

[0009] 2) The ethylene tar from which quinoline insolubles and ash have been removed is transported to a first stirred tank reactor via a gear pump, the ethylene tar is heated to 230-250°C, and the light components are separated by vacuum to obtain heavy tar;

[0010] 3) transferring a portion of the heavy tar to a second stirred tank reactor via a gear pump, introducing air, and reacting at 250-340° C. for 2-10 hours, with a stirring speed of 200-300 r / min and a reaction pressure of 40-90 kPa to produce medium-temperature petroleum asphalt;

[0011] 4) delivering the medium-temperature petroleum asphalt to a third stirred tank reactor by a gear pump, and simultaneously delivering a certain amount of the heavy tar obtained in step (2) to the third stirred tank reactor by a gear pump, and stirring and mixing the two to react;

[0012] 5) The liquid asphalt obtained from the third kettle-type stirred reactor is transported to the asphalt forming machine by a gear pump, thereby obtaining an impregnating agent asphalt with zero quinoline insoluble matter.

[0013] The ethylene tar has a softening point of 20-35° C., a quinoline insoluble matter content of 0.01-0.1%, and an ash content of less than 100-500 ppm.

[0014] The heavy tar has a softening point of 40-60° C., a quinoline insoluble matter content of 0%, an ash content of 0%, and a coking value of 8-14%.

[0015] The medium-temperature petroleum asphalt has a softening point of 120-160° C., a quinoline insoluble matter content of 0%, an ash content of 0%, and a coking value of 48-56%.

[0016] The mass ratio of the medium-temperature petroleum asphalt to the heavy tar in the third kettle-type stirred reactor is 1-49:1; the reaction temperature is 150-250° C., the reaction pressure is 0.1-0.5 MPa, and the stirring time is 1-4 hours.

[0017] Compared with the prior art, the present invention has the following beneficial effects.

[0018] 1. The quinoline insoluble matter in the impregnating asphalt prepared by the present invention is 0%. The material has good rheological properties in the liquefied state, which can reduce the number of impregnations in the production process of graphite electrodes.

[0019] Second, by adjusting the air oxidation conditions, the coking value of the prepared impregnating agent asphalt still reaches 45-48%, which improves the residual carbon rate of the impregnating agent asphalt to a certain extent.

[0020] 3. Ethylene tar is cheap, and the production cost of the impregnating asphalt made from it is low, providing high-quality impregnating asphalt products for the domestic graphite electrode industry.

[0021] Fourth, converting ethylene tar with extremely low added value into impregnating asphalt effectively solves a major problem facing the petrochemical industry. DETAILED DESCRIPTION

[0022] The present invention will be further described with reference to the following examples.

[0023] Example 1

[0024] Using ethylene tar with a softening point of 23°C, a QI content of 0.02% and an ash content of 110ppm as raw material, the ethylene tar is heated to 100°C using a tubular reactor and then flows into a ceramic plate filter to remove the QI and ash from the ethylene tar. The heavy tar with the QI and ash removed is transported to a 3m 3 In the first stirred tank reactor, ethylene tar was heated to 250°C and the light components were separated by vacuum extraction at a pressure of 50 kPa. The resulting heavy tar had a softening point of 42°C, a QI content of 0%, an ash content of 0%, and a coking value of 13%.

[0025] Example 2

[0026] Using ethylene tar with a softening point of 23°C, a QI content of 0.02% and an ash content of 110ppm as raw material, the ethylene tar is heated to 100°C using a tubular reactor and then flows into a ceramic plate filter to remove the QI and ash from the ethylene tar. The heavy tar with the QI and ash removed is transported to a 3m 3 In the first stirred tank reactor, ethylene tar was heated to 236°C and the light components were separated by vacuum extraction at a pressure of 50 kPa. The heavy tar produced had a softening point of 35°C, a QI content of 0%, an ash content of 0%, and a coking value of 10%.

[0027] Example 3

[0028] The heavy tar prepared in Example 1 was transported to a 2.5 m 3In a second stirred reactor, air was introduced and the reaction was carried out at 300°C for 6 hours with a stirring speed of 200 r / min and a reaction pressure of 50 kPa to produce medium-temperature petroleum asphalt. The medium-temperature petroleum asphalt had a softening point of 135°C, a QI content of 0%, an ash content of 0%, and a coking value of 46%.

[0029] Example 4

[0030] The heavy tar prepared in Example 1 was transported to a 2.5 m 3 In a second stirred reactor, air was introduced and the reaction was carried out at 300°C for 9 hours with a stirring speed of 200 r / min and a reaction pressure of 50 kPa to produce medium-temperature petroleum asphalt. The medium-temperature petroleum asphalt had a softening point of 158°C, a QI content of 0%, an ash content of 0%, and a coking value of 49.7%.

[0031] Example 5

[0032] The heavy tar prepared in Example 1 was transported to a 2.5 m 3 In a second stirred reactor, air was introduced and the reaction was carried out at 300°C for 9 hours with a stirring speed of 200 r / min and a reaction pressure of 80 kPa to produce medium-temperature petroleum asphalt. The medium-temperature petroleum asphalt had a softening point of 142°C, a QI content of 0%, an ash content of 0%, and a coking value of 47.1%.

[0033] Example 6

[0034] The heavy tar prepared in Example 1 was transported to a 2.5 m 3 In a second stirred reactor, air was introduced and the reaction was carried out at 340°C for 6 hours with a stirring speed of 200 r / min and a reaction pressure of 50 kPa to produce medium-temperature petroleum asphalt. The medium-temperature petroleum asphalt had a softening point of 161°C, a QI content of 0%, an ash content of 0%, and a coking value of 54%.

[0035] Example 7

[0036] The medium temperature petroleum asphalt prepared in Example 3 was transported to a 2m 3 A third stirred reactor was added, and the heavy tar prepared in Example 1 was simultaneously transferred to stirred reactor 3 via a gear pump. When the mass ratio of medium-temperature petroleum asphalt to heavy tar was 80%:20%, the mixing temperature was 160°C, the mixing pressure was 0.2 MPa, and the stirring time was 3 hours, a liquid impregnating agent pitch was produced. The liquid impregnating agent pitch was transferred from the third stirred reactor to an asphalt forming machine via a gear pump to produce a solid impregnating agent pitch. The solid impregnating agent pitch produced had a QI content of 0%, an ash content of 0%, a softening point of 68°C, and a coking value of 37%.

[0037] Example 8

[0038] The medium temperature petroleum asphalt prepared in Example 3 was transported to a 2m 3 A third stirred reactor was added, and the heavy tar prepared in Example 1 was simultaneously transferred to stirred reactor 3 via a gear pump. When the mass ratio of medium-temperature petroleum asphalt to heavy tar was 90%:10%, the mixing temperature was 160°C, the mixing pressure was 0.2 MPa, and the stirring time was 3 hours, a liquid impregnating agent pitch was produced. The liquid impregnating agent pitch was transferred from the third stirred reactor to an asphalt forming machine via a gear pump to produce a solid impregnating agent pitch. The solid impregnating agent pitch had a QI content of 0%, an ash content of 0%, a softening point of 75°C, and a coking value of 41.5%.

[0039] Example 9

[0040] The medium temperature petroleum asphalt prepared in Example 4 was transported to a 2m 3 A third stirred reactor was added, and the heavy tar prepared in Example 1 was simultaneously transferred to stirred reactor 3 via a gear pump. When the mass ratio of medium-temperature petroleum asphalt to heavy tar was 90%:10%, the mixing temperature was 160°C, the mixing pressure was 0.2 MPa, and the stirring time was 3 hours, a liquid impregnating agent pitch was produced. The liquid impregnating agent pitch was transferred from the third stirred reactor to an asphalt forming machine via a gear pump to produce a solid impregnating agent pitch. The solid impregnating agent pitch had a QI content of 0%, an ash content of 0%, a softening point of 87°C, and a coking value of 45.3%.

[0041] Example 10

[0042] The medium temperature petroleum asphalt prepared in Example 6 was transported to a 2m 3 A third stirred reactor was added, and the heavy tar prepared in Example 1 was simultaneously transferred to stirred reactor 3 via a gear pump. When the mass ratio of medium-temperature petroleum asphalt to heavy tar was 80%:20%, the mixing temperature was 160°C, the mixing pressure was 0.2 MPa, and the stirring time was 3 hours, a liquid impregnating agent pitch was produced. The liquid impregnating agent pitch was transferred from the third stirred reactor to an asphalt forming machine via a gear pump to produce a solid impregnating agent pitch. The solid impregnating agent pitch had a QI content of 0%, an ash content of 0%, a softening point of 81°C, and a coking value of 43.4%.

[0043] Example 11

[0044] The medium temperature petroleum asphalt prepared in Example 6 was transported to a 2m 3A third stirred reactor was added, and the heavy tar prepared in Example 1 was simultaneously transferred to stirred reactor 3 via a gear pump. When the mass ratio of medium-temperature petroleum asphalt to heavy tar was 90%:10%, the mixing temperature was 160°C, the mixing pressure was 0.2 MPa, and the stirring time was 3 hours, a liquid impregnating agent pitch was produced. The liquid impregnating agent pitch was transferred from the third stirred reactor to an asphalt forming machine via a gear pump to produce a solid impregnating agent pitch. The solid impregnating agent pitch had a QI content of 0%, an ash content of 0%, a softening point of 98°C, and a coking value of 48.7%.

[0045] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Those skilled in the art may modify or improve the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical concepts disclosed herein shall be encompassed by the claims of the present invention.

Claims

1. A method for preparing an impregnating agent having a zero quinoline insoluble content, characterized in that: The following steps are involved: 1) Ethylene tar is heated to 80-150°C in a reactor, and then quinoline insoluble matter and ash are removed from the ethylene tar using a ceramic plate filter; 2) The ethylene tar from which quinoline insolubles and ash have been removed is transferred to a first stirred tank reactor, where the ethylene tar is heated to 230-250°C and the light components are separated by vacuum to obtain heavy tar; 3) transferring a portion of the heavy tar to a second stirred reactor, introducing air, and reacting at 250-340° C. for 2-10 hours, with a stirring speed of 200-300 r / min and a reaction pressure of 40-90 kPa to produce medium-temperature petroleum asphalt; 4) transporting the medium-temperature petroleum asphalt to a third stirred tank reactor, and simultaneously adding a portion of the heavy tar to the third stirred tank reactor, stirring and mixing the two to react; 5) The liquid asphalt obtained from the third stirred tank reactor is transported to an asphalt forming machine to produce an impregnating agent asphalt containing zero quinoline insoluble matter; The ethylene tar has a softening point of 20-35° C. and a quinoline insoluble content of 0.01-0.1%; The mass ratio of the medium-temperature petroleum asphalt to the heavy tar in the third kettle-type stirred reactor is 1-49:1; the reaction temperature is 150-250° C., the reaction pressure is 0.1-0.5 MPa, and the stirring time is 1-4 hours.

2. The method for preparing an impregnating agent having a zero quinoline insoluble content according to claim 1, wherein: The heavy tar has a softening point of 40-60° C., a quinoline insoluble matter content of 0%, an ash content of 0%, and a coking value of 8-14%.

3. The method for preparing an impregnating agent having a zero quinoline insoluble content according to claim 1, wherein: The medium-temperature petroleum asphalt has a softening point of 120-160° C., a quinoline insoluble matter content of 0%, an ash content of 0%, and a coking value of 48-56%.