CN106147835B - A kind of separation catalytic cracked oil pulp simultaneously prepares the combined method that oil is needle coke - Google Patents
A kind of separation catalytic cracked oil pulp simultaneously prepares the combined method that oil is needle coke Download PDFInfo
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Abstract
The present invention provides a kind of separation catalytic cracked oil pulp and prepares the combined method that oil is needle coke.Extractant is made using C3 C5 light ends fractionations, subcritical or supercritical extract is carried out to catalytic cracked oil pulp, extracted component is made through supercritical recovery solvent to obtained extraction oil phase, raw material is prepared using extracted component as mesophase pitch, mesophase pitch is prepared through thermal polycondensation reaction, then the delayed pyrogenetic reaction of mesophase pitch is prepared to the oil system needle coke of high-quality.When the sulfur content of catalytic cracked oil pulp is higher, light component first hydrogenated desulfurization process can will be extracted, carrying out fractionation to hydrogenated oil collects hydrogenation tail oil, prepares raw material using hydrogenation tail oil as mesophase pitch, and then prepare needle coke.The method of the present invention is mutual indepedent by the preparation of control mesophase pitch and the coking process of needle coke, more conducively realization of industrialization, and can make full use of catalytic cracked oil pulp and prepare the needle coke material of high-quality.
Description
Technical Field
The invention relates to a combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke, in particular to a combined process for producing the oil-based needle coke by separating the catalytic cracking slurry oil and delaying coking.
Background
Needle coke is a carbon material and is mainly used for the production of high-power and ultrahigh-power graphite electrodes. According to different sources of preparation raw materials, the needle coke is divided into an oil system and a coal system, wherein the oil system needle coke is processed by heavy oil in an oil refinery, is widely applied, has large market demand and has insufficient production capacity. In the prior art, the production of oil-based needle coke generally adopts a delayed coking process, which comprises three parts of raw oil pretreatment, delayed coking coke formation and calcination, but two technical difficulties of raw material refining and coke formation process control exist in the actual industrial production, so that a high requirement on process control is provided for obtaining a high-quality needle coke product. The process for producing the needle coke by using the raw oil comprises the following steps: the raw oil is pretreated and reacted to prepare intermediate phase asphalt, and the intermediate phase asphalt is subjected to delayed coking and calcination to generate needle coke, so that the intermediate phase asphalt is not only an important intermediate raw material for producing the needle coke, but also the quality of the intermediate phase asphalt can influence the quality of the needle coke.
With the popularization and application of the heavy oil catalytic cracking technology, the quantity of byproduct oil slurry (FCC oil slurry) of a catalytic cracking unit is larger and larger, the processing capacity of the catalytic cracking unit in China reaches 2 hundred million tons, and the conservative estimation of the national oil slurry yield is about 750 million tons/year. The treatment and utilization of oil slurry are also attracting more and more attention in the field of heavy oil processing, and at present, most of catalytic cracking oil slurry is doped with fuel oil or directly used as fuel oil, and part of oil slurry is used as an asphalt blending component, so that not only is precious petroleum resources not utilized, but also the abrasion and coking of a heating furnace burner are easily caused due to the existence of impurities such as residual catalyst and the like in the combustion process. However, the catalytic cracking slurry oil has poor cracking reaction performance, low conversion rate and low light oil yield, and continuous accumulation and circulation of the catalytic cracking slurry oil in a catalytic cracking unit leads to increased coking and deactivation of the catalyst, so that the catalyst consumption is increased, and finally, the economic benefit is rather poor.
The FCC slurry oil contains components rich in aromatic hydrocarbon, is a valuable chemical raw material and a raw material for preparing carbon materials, can be used for producing various aromatic hydrocarbon oils and used as a raw material of mesophase pitch, and is also a raw material for producing needle coke. However, the catalytic slurry oil is a very complex system in which colloids, asphaltenes and small amounts of other solid impurities, if not effectively processed for direct use in the production of mesophase pitch, can lead to mosaic formation, which makes it difficult to form high quality mesophase pitch, and further affects the quality of needle coke.
Therefore, how to effectively refine the catalytic cracking slurry oil raw material becomes one of the key problems of preparing high-quality mesophase pitch by using good slurry oil raw material and further obtaining high-quality oil-based needle coke. For solid impurities in the oil slurry, the method such as filtration can only separate larger particles, and for solid particles with smaller particle size, such as catalyst powder, the method is difficult to separate, and cannot remove components such as asphaltene in the solid particles. Vacuum distillation and solvent extraction are common heavy oil separation methods, but the vacuum distillation extraction rate is limited, if the distillation extraction rate needs to be increased, the distillation temperature needs to be increased, and because the content of polycyclic aromatic hydrocarbon in slurry oil and impurities such as asphaltene and the like exist, coking is easily caused in a heating furnace and a distillation tower by high-temperature distillation, so that the extraction rate of an extract is difficult to increase, and the service life of equipment is shortened. As for the solvent extraction technology, there are research and well-known operations, and it is a desired goal to try to separate the aromatic hydrocarbon components from the oil slurry, so according to the properties of the catalytic cracking oil slurry, extraction and separation by using a solvent capable of extracting aromatic hydrocarbons, such as furfural, is a technological direction which is currently researched and focused, but the problem in industrial production is that in the system of oil slurry, although aromatic hydrocarbons can be extracted by the furfural solvent, the extraction of colloidal asphaltene is also performed at the same time, so that not only the phase separation of the extract and non-aromatic hydrocarbons is difficult to be realized, but also the refining purpose of the raw material of oil slurry is difficult to be achieved, and therefore, the technology needs to be applied after the pretreatment of deasphalted substances and solid impurities on the oil slurry. On the other hand, the properties of crude oil and the catalytic cracking process also cause the difference of the properties of oil slurry, particularly for the oil slurry with high-sulfur aromatic hydrocarbon components, the direct use of the oil slurry as a raw material can seriously affect the quality of mesophase pitch and needle coke, but the direct hydrotreatment of the oil slurry can cause the blockage of a catalyst bed layer and the failure of a catalyst quickly due to impurities in the oil slurry, so the oil slurry is not preferable in industrial production and is a difficult problem in the production of the mesophase pitch, and the technical problem is brought to the subsequent process for preparing high-quality needle coke products by adopting the mesophase pitch.
In addition, the process for preparing the needle coke at present basically adopts a delayed coking device, and the coking device needs to complete both the synthesis of the mesophase pitch and the preparation of the needle coke by a coking reaction, so that the process conditions need to be changed in each cycle, the temperature and pressure change is large, the control of the coking process is difficult, and the quality of the needle coke is difficult to ensure.
Disclosure of Invention
The invention provides a combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke, which utilizes the catalytic cracking slurry oil as a raw material, adopts a more reasonable and scientific method to separate the catalytic cracking slurry oil, and combines the catalytic cracking slurry oil with a preparation process of mesophase pitch and a delayed coking process, but the thermal polycondensation process for preparing the mesophase pitch and the coking process for preparing the needle coke are controlled independently, thereby being more beneficial to industrial realization, and being capable of fully utilizing the catalytic cracking slurry oil and preparing high-quality needle coke materials.
The invention provides a combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke, which comprises the following steps:
the method comprises the steps of enabling a catalytic cracking slurry oil raw material to be in countercurrent contact with an extraction solvent in an extraction tower, enabling the extraction solvent to realize extraction of the catalytic cracking slurry oil under a supercritical or subcritical condition to form an extraction oil phase and a raffinate phase, carrying out supercritical separation on the extraction oil phase to obtain an extraction component, and recovering the extraction solvent from the raffinate phase to obtain a raffinate heavy component;
taking the extracted component as a raw material for preparing the intermediate phase asphalt, and carrying out thermal polycondensation reaction to prepare the intermediate phase asphalt;
preparing oil-based needle coke by using the obtained mesophase pitch and adopting a delayed coking technology;
wherein,
the components of the extraction solvent are C3-C5 light hydrocarbon fractions, and the pseudo-critical temperature Tc of the extraction solvent is between 90 and 196 ℃, and the pseudo-critical temperature Tc is expressed by the formulaTo obtain a compound of the formula wherein xiIs the molar fraction of component i, Tc, in the light hydrocarbon fractioniIs the critical temperature of the component i, and n is the number of components contained in the extraction solvent.
According to the combined method, catalytic cracking slurry oil is used as a raw material, and the process of preparing needle coke by preparing mesophase pitch and further coking is included. In the process of treating the catalytic cracking oil slurry, firstly, selected light hydrocarbon is used as an extraction solvent, the catalytic cracking oil slurry is controlled to be extracted under the subcritical or supercritical condition of the extraction solvent, impurities in the oil slurry are removed, meanwhile, asphaltene and part of colloid which are harmful to mesophase pitch are removed, the catalytic cracking oil slurry is purified, meanwhile, the obtained extraction oil phase also realizes the concentration of aromatic hydrocarbon components, the supercritical separation process of the extraction oil phase is matched, so that the raw material with improved quality is obtained, the mesophase pitch with high quality is prepared by heat supply and polycondensation, then the mesophase pitch is subjected to delayed coking to prepare the needle coke, the decoupling of the thermal polycondensation process and the delayed coking process is realized, the contradiction on the reaction conditions of the synthesis and coking of the mesophase pitch is solved, and the high-quality oil-series needle coke product is further prepared.
According to the combination method, the extraction oil phase is subjected to supercritical separation extraction solvent to obtain an extraction component, the extraction component is selected as a raw material, a thermal polycondensation process is carried out to obtain high-quality mesophase pitch, and then the delayed coking technology is combined to obtain the oil-based needle coke product.
In a further embodiment, when the intermediate phase asphalt preparation raw material is subjected to thermal polycondensation reaction to prepare the intermediate phase asphalt, the reaction pressure is 0.1-3.0MPa, the reaction temperature is 400-.
In a further embodiment, when the mesophase pitch is made into needle coke by delayed coking reaction, the raw material feeding temperature is 480-510 ℃, the reaction pressure is 0.1-1.0MPa, and the reaction time is 12-36 h. The specific operation of the delayed coking of the mesophase pitch to produce needle coke may be the same as in the prior art, and the present invention is not particularly limited. For example, the production can be switched between two coke drums or three coke drums, in the coking reaction process, the reaction oil gas flows out from the top of the coke drum, the generated needle coke is left in the coke drum, when the coke removal of the coke drum for coke formation is completed, the other coke drum is used for continuing the reaction, and the needle coke obtained from the coke drum is subjected to further high-temperature calcination (generally 1300 ℃ and 1500 ℃) to obtain the high-quality oil-based needle coke product.
The differences of crude oil properties and processing techniques result in the obvious differences of the compositions and properties of the formed catalytic cracking slurry oils, particularly the slurry oils with high sulfur content need to be desulfurized before being used for subsequent processing, but the catalytic bed layer is easily failed by directly carrying out desulfurization. Therefore, the embodiment of the present invention for separating catalytic cracking slurry oil can further comprise a hydrodesulfurization process, that is, if the sulfur content of the catalytic cracking slurry oil raw material is more than or equal to 0.5 m%, the combined method further comprises:
subjecting the extracted components to hydrodesulfurization treatment, and fractionating the treated hydrogenated oil to obtain hydrogenated light fraction and hydrogenated tail oil, wherein the cut point of the fraction is 350-450 ℃, the sulfur content of the hydrogenated tail oil with the boiling point higher than the cut point is less than or equal to 0.3 m%, and the density is 0.970g/cm3-1.050g/cm3The content of aromatic hydrocarbon is 40-65 m%;
the hydrogenated tail oil is used as a raw material for preparing mesophase pitch.
In particular embodiments provided herein for catalysisUnder the condition that the sulfur content of the cracking slurry oil raw material is more than or equal to 0.5m percent, residual oil hydrodesulfurization catalyst can be adopted when the hydrodesulfurization treatment is carried out on the extraction component, the hydrotreating pressure is 6-16MPa, the volume ratio of hydrogen to oil is 200:1-1200:1, and the airspeed is 0.2-2.0h-1。
For the high-sulfur oil slurry, the scheme of the invention is to remove the raffinate heavy component and then implement hydrodesulfurization, so that the problem of taking the high-sulfur aromatic hydrocarbon component as a hydrotreating feed under the high-sulfur condition is solved, the product obtained after hydrodesulfurization of the high-sulfur aromatic hydrocarbon component is taken as a raw material for preparing mesophase pitch, and the high-quality mesophase pitch raw material is subjected to thermal polycondensation to prepare the high-quality mesophase pitch, so that the preparation of the high-quality oil system needle coke product is facilitated.
For most cases of catalytic cracking slurries, the combined process of the present invention may include a process of first separating the extraction system, i.e.,
the method comprises the steps of enabling a catalytic cracking slurry oil raw material to be in countercurrent contact with an extraction solvent in an extraction tower, enabling the extraction solvent to extract the catalytic cracking slurry oil under a supercritical or subcritical condition to form an extraction oil phase and a raffinate phase, feeding the extraction oil phase into a separation tower, heating and separating the extraction oil phase into a light oil phase and a heavy oil phase, and recovering the extraction solvent from the raffinate phase to obtain a raffinate heavy component;
carrying out supercritical separation extraction on the light oil phase to obtain an extracted light component, and separating the heavy oil phase from the solvent to obtain an extracted intermediate component;
taking the extracted intermediate component or the mixture of the extracted intermediate component and the extracted light component as an intermediate phase asphalt preparation raw material, and carrying out thermal polycondensation reaction to prepare intermediate phase asphalt, wherein the mass content of the extracted light component in the mixture is not more than 50%;
the obtained mesophase pitch is used for preparing the oil-based needle coke by adopting a delayed coking technology.
Therefore, the combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke provided by the invention comprises the working procedures of extracting catalytic cracking slurry oil raw materials by using a light hydrocarbon solvent in a supercritical or subcritical state, performing necessary heavy and light oil separation treatment and supercritical separation solvent for an extraction system, performing necessary hydrodesulfurization treatment and thermal polycondensation to prepare mesophase pitch, and preparing needle coke by delayed coking, and becomes a mutually matched combined process, so that the refining of the slurry oil can be realized, the catalytic cracking slurry oil is fully utilized, a high-quality mesophase pitch product (the wide-area anisotropic structure ratio of the mesophase pitch product can be obviously improved and can reach more than 90 percent) is prepared by using the obtained polycondensation raw materials, the preparation of the mesophase pitch and the coking working procedure are decoupled, the industrial realization is facilitated, and the contradiction between the conditions of mesophase pitch synthesis and coking reaction conditions is solved, further solves the problem of difficult control of the coking process, thereby obtaining the high-quality needle coke.
Drawings
FIG. 1 is a schematic process flow diagram of an embodiment of the combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke provided by the invention.
Detailed Description
The invention provides a combined method for extracting and separating catalytic cracking slurry oil and preparing needle coke, which comprises the steps of firstly adopting C3-C5 light hydrocarbon fraction as an extraction solvent, extracting the catalytic cracking slurry oil under the subcritical or supercritical condition of the extraction solvent, and separating or recovering the extraction solvent to obtain an extraction component, wherein main impurity ash, catalyst particles and the like in the slurry oil are removed to a raffinate heavy component, and simultaneously almost all C7 asphaltene (n-heptane insoluble substance) and part of heavy colloid are separated to the raffinate heavy component, and the concentration of aromatic hydrocarbon components in the slurry oil is realized through the removal of poor components; the extraction component obtained by supercritical separation of the extraction solvent can be used as a raw material for preparing mesophase pitch; the oil slurry raw material with the sulfur content of more than or equal to 0.5m percent is further combined with a hydrodesulfurization process, so that the sulfur content of the intermediate asphalt phase preparation raw material is reduced, the content of other impurities, the total content of C7 asphaltene and metal is further reduced, and the quality of the obtained needle coke product is further improved.
In a further aspect, for most of the catalytically cracked slurry oil raw materials obtained by the process, the extraction oil phase can be separated first to prepare the mesophase pitch preparation raw material, which has wider adaptability, especially for slurry oil which is not very heavy, the combined method for separating catalytically cracked slurry oil and preparing oil-based needle coke of the present invention may comprise the following steps:
the method comprises the steps of enabling a catalytic cracking slurry oil raw material to be in countercurrent contact with an extraction solvent in an extraction tower, enabling the extraction solvent to extract the catalytic cracking slurry oil under a supercritical or subcritical condition to form an extraction oil phase and a raffinate phase, feeding the extraction oil phase into a separation tower, heating and separating the extraction oil phase into a light oil phase and a heavy oil phase, and recovering the extraction solvent from the raffinate phase to obtain a raffinate heavy component;
carrying out supercritical separation extraction on the light oil phase to obtain an extracted light component, and separating the heavy oil phase from the solvent to obtain an extracted intermediate component;
taking the extracted intermediate component or the mixture of the extracted intermediate component and the extracted light component as an intermediate phase asphalt preparation raw material, and carrying out thermal polycondensation reaction to prepare intermediate phase asphalt, wherein the mass content of the extracted light component in the mixture is not more than 50%;
preparing oil-based needle coke by using the obtained mesophase pitch and adopting a delayed coking technology;
wherein,
the components of the extraction solvent are C3-C5 light hydrocarbon fractions, and the pseudo-critical temperature Tc of the extraction solvent is between 90 and 196 ℃, and the pseudo-critical temperature Tc is expressed by the formulaTo obtain a compound of the formula wherein xiIs the molar fraction of component i in the light hydrocarbon fractionNumber, TciIs the critical temperature of the component i, and n is the number of components contained in the extraction solvent.
In the specific embodiment of the invention, the light hydrocarbon solvent is used for supercritical extraction of the slurry oil, and a conventional extraction tower can be selected as long as the countercurrent contact of the solvent and the slurry oil is realized, such as a sieve plate tower or a packed tower, so that the catalytic cracking slurry oil raw material enters the tower from the upper part of the extraction tower, the tower entering temperature is 70-200 ℃, the extraction solvent enters the tower from the bottom of the extraction tower, the tower entering temperature is 50-180 ℃, the pressure of the extraction tower is 3.0-10.0MPa, the mass ratio of the extraction solvent to the catalytic cracking slurry oil raw material (the mass ratio of the solvent to the oil) is 1.5-5.0:1, the extraction oil phase is separated from the top of the extraction tower, and the raffinate phase is separated from the bottom of the.
Based on the research on the properties and the composition of catalytic cracking slurry oil, the invention selects C3-C5 light hydrocarbon solvent to extract the slurry oil (control subcritical or supercritical conditions), utilizes the extraction solvent and corresponding extraction conditions to extract components of the slurry oil, and further separates the extracted light components and the extracted intermediate components which are basically free of asphaltene and solid (ash), so that the difficulty of subsequent separation treatment is reduced, and the obtained thermal polycondensation raw material is favorable for preparing intermediate phase asphalt with improved quality, for example, the wide area anisotropic structure proportion is improved, and the high-quality intermediate phase asphalt is favorable for obtaining high-quality needle coke products.
The light hydrocarbon solvent selected for use in the present invention is a mixture of light hydrocarbons having a composition of C3 to C5, and may typically be normal/iso-alkanes and alkenes, for example, and may comprise some or all of the components propane, propylene, isobutane, n-butane, butene-1, butene-2, isobutene, n-pentane, isopentane, neopentane, and C5 alkenes. The hydrocarbon component may be selected according to the nature and composition of the slurry, or the solvent component may be selected to be "heavier" (slightly higher carbon number) if the "heavy" and "lighter" solvent components are determined, e.g., if the slurry is of higher density. The specific scheme for separating the extraction oil phase comprises heating the extraction oil phase to a temperature 5-90 deg.C higher than the temperature of the top of the extraction tower, introducing into a separation tower with a separation pressure of 3.0-10.0MPa, wherein the separation tower can be selected from empty tower and sieveAnd the heavy oil phase is discharged from the bottom of the tower, the extracted intermediate component is obtained after the solvent is separated, the light oil phase is separated from the top of the tower, and the extraction solvent is separated through supercritical separation to obtain the extracted light component. The light hydrocarbon solvent is adopted, so that the required extraction effect is met, and the solvent is favorably separated from the extracted oil phase to obtain the raw material for preparing the mesophase pitch by thermal polycondensation, namely, the extraction of oil slurry components and the phase splitting and separating effects of an extraction system are met. The invention also selects the light hydrocarbon solvent of C3-C5, and the separated light oil phase can also adopt a supercritical method to recover the solvent when extracting intermediate components from the oil phase. The corresponding supercritical conditions are controlled according to the properties of the used light hydrocarbon solvent, and the solvent can be recovered in a single fluid phase by determining the proper separation pressure, so that the separation from the extraction oil slurry is realized. In a supercritical state and a set separation pressure, theoretically, the higher the separation temperature is, the lower the density of the solvent is, and the faster the fluid velocity is, so that the operation cost and the control requirement are correspondingly higher in order to reduce the carrying of the solvent to the light oil phase. In a particular embodiment of the invention, the extraction solvent is subjected to supercritical separation such that the density of the solvent is less than 0.20g/cm3The separation pressure is 3.0-10.0MPa, and the separation temperature is controlled to be not higher than 280 ℃.
The catalytic cracking slurry oil is derived from a byproduct of a catalytic cracking process of oil refining processing, the property and processing process difference of crude oil can cause the difference of the discharged slurry oil byproduct, and the difference is generally reflected on indexes such as sulfur content, asphaltene content, particle impurity content and the like. The catalytic cracking slurry oil feedstock suitable for use in embodiments of the present invention may generally be: density 0.970g/cm3-1.200g/cm3And oil slurry carbon residue<21.0 m%, C7 asphaltene content<10.0 m%, ash content<3.0 m%, sulfur content<3.0 m%. A further option is for relatively "heavy" slurry feedstocks, for example having a density of 1.000g/cm3-1.200g/cm3Or directly transferring the extracted oil phase after extraction into a supercritical solvent recovery process without separation treatment by a separation tower.
The sulfur content is an important index for evaluating the properties of the slurry oil, and excessive sulfur brought into the hot polycondensation raw material has a certain influence on the quality of the polycondensation product. Although it is a feasible scheme to implement desulfurization by adopting a proper means for the slurry oil raw material before extraction and separation, the problem to be solved by the direct hydrodesulfurization of the slurry oil is damage to a catalyst bed and catalyst failure, which leads to the hindrance of industrial application, so in the embodiment of the invention, for the slurry oil with high sulfur content, the extraction and separation are carried out by using a light hydrocarbon solvent, the collected extraction intermediate component or the mixture of the extraction intermediate component and the extraction light component is subjected to hydrodesulfurization treatment, and the components such as asphaltene and colloid in the slurry oil are removed, and at the moment, the slurry oil is used as the hydrodesulfurization raw material, and can be easily controlled in both feeding and separation. The specific treatment of hydrodesulfurization can be determined by conventional methods including the use of catalysts and treatment processes.
In particular embodiments provided herein, sulfur content for a catalytically cracked slurry oil feedstock<0.5 m% slurry oil, directly using the separated extracted intermediate component as intermediate phase asphalt preparation raw material, or mixing the separated extracted intermediate component with the obtained extracted light component according to a certain proportion as intermediate phase asphalt preparation raw material (mixed raw material), and preparing intermediate phase asphalt by thermal polycondensation. The mixing ratio can be expressed as: the extraction light component, namely the extraction intermediate component is 0-50% to 100-50%, and the specific determination of the mixing ratio can be based on the original yield ratio of the separation product, for example, the density of the mixed raw material is controlled to be 1.0-1.1g/cm3Sulfur content is less than or equal to 0.4 m%, aromatic hydrocarbon content is 40-65 m%, the aromatic hydrocarbon content in the thermal polycondensation raw material is ensured, simultaneously the amount of the thermal polycondensation raw material for use can be adjusted, the yield of mesophase pitch is improved, of course, after extraction separation treatment, the impurity content of the obtained mixed raw material is obviously controlled, namely, the ash content<0.01%, C7 asphaltenes<0.1%, total content of metal Ni, V, Al, Fe, Na and Ca<5 μ g/g. The treatment of the thermal polycondensation raw materials is also advantageous for the preparationThe ratio of the wide-area anisotropic structure of the mesophase pitch is high (more than 90 percent), thereby providing a high-quality raw material for preparing high-quality needle coke.
In the specific embodiment provided by the invention, under the condition that the sulfur content of the catalytic cracking slurry oil raw material is more than or equal to 0.5m percent, the hydrodesulfurization treatment is firstly carried out on the extracted intermediate component or the mixture of the extracted intermediate component and the extracted light component, a residual oil hydrodesulfurization catalyst can be adopted, the hydrotreating pressure is 6-16MPa, the volume ratio of hydrogen to oil is 200:1-1200:1, and the space velocity is 0.2-2.0h-1。
In the above-mentioned scheme, it is advantageous to carry out mild hydrodesulfurization of the extract fraction, and excessive cracking is avoided as much as possible in hydrodesulfurization, so that a desulfurization catalyst for hydrotreating of a residual oil can be selected, which is advantageous in employing a hydrogenation process that is mild as possible, i.e., at a temperature as low as possible, in combination with appropriate pressure, hydrogen-to-oil ratio and space velocity. The residual oil hydrodesulfurization catalyst is a common and well-known hydrogenation catalyst in the field of heavy oil processing, and is a gamma-Al catalyst2O3The catalyst has supported VIII and/or VIB metal elements as active component and certain pore volume and pore distribution, and is not limited specially and available.
Fractionating the treated system, namely hydrogenated oil to collect hydrogenated light fraction and hydrogenated tail oil, setting the cut point of the fraction at 350-450 ℃, setting the sulfur content of the hydrogenated tail oil with the boiling point higher than the cut point to be less than or equal to 0.3 m%, and setting the density to be 0.970g/cm3-1.050g/cm3And the aromatic hydrocarbon content is 40-65 m%, and the reaction light component with the boiling point lower than the cut point generated by the reaction is discharged by flash evaporation to obtain a fraction (hydrogenation tail oil) with the boiling point higher than the cut point as a raw material for preparing the mesophase pitch. It is also advantageous to increase the cut point temperature appropriately in this temperature range to improve the quality of the mesophase pitch produced, for example, at a cut point of 420-450 ℃.
In this embodiment, the hydrogenated tail oil may be used directly as a feedstock for mesophase pitch production, or alternatively, the hydrogenated tail oil may be used as a feedstock for mesophase pitch production, as previously discussed with respect to low sulfur slurry processingMixing the intermediate phase asphalt with the extracted light components in a certain proportion to be used as a raw material for preparing the intermediate phase asphalt, and performing thermal polycondensation to prepare the intermediate phase asphalt. The mixing proportion of the extracted light component is 0-40% of hydrogenated tail oil and 100-60%, and the density of the mixed raw material is controlled to be 0.970-1.1g/cm3Total content of metals Ni, V, Al, Fe, Na and Ca<2 μ g/g, the remaining parameters being as described above for the low sulfur slurry.
The mesophase pitch prepared by the method has high wide-area anisotropic structure proportion (more than 90 percent), is a high-quality raw material for preparing high-performance carbon materials, and is beneficial to preparing high-quality oil-based needle coke products by decoupling the mesophase pitch preparation and the coking process.
The method of the invention carries out high-temperature calcination (generally 1300 ℃ and 1500 ℃) on the obtained needle coke, and then carries out mass analysis: measuring the thermal expansion coefficient at room temperature to 600 ℃ according to a petroleum coke thermal expansion coefficient measuring standard method RIPP 24-90; measuring the true density of the needle coke by GB/T6155-2008; measuring the sulfur content of the needle coke by GB/T24526-2009; determining the volatile matter of the carbon material by YB/T5189; measuring ash content by GB/T1429; the test method of the resistivity adopts GB/T24511.
Compared with the currently used technology, the core effect of the invention is as follows: after the catalytic cracking slurry oil is extracted and separated, the extracted light component and the extracted intermediate component are basically free of asphaltene and solid (ash), the extracted intermediate component and the extracted light component or the hydrogenated tail oil and the extracted light component are mixed according to a certain proportion to obtain a high-quality intermediate phase asphalt raw material, and the density of the intermediate phase asphalt raw material is 0.970-1.1g/cm3(more preferably 1.0 to 1.1 g/cm)3) Sulfur content<0.4 m%, aromatic hydrocarbon content of 40-65 m%, ash content<0.01%, C7 asphaltenes<0.1%, total content of metal Ni, V, Al, Fe, Na and Ca<5. mu.g/g (more preferably, it is<2 mu g/g) under proper thermal polycondensation conditions, and further decoupling the preparation of the mesophase pitch from the coking process, thereby solving the contradiction between the synthesis of the mesophase pitch and the coking reaction conditions and obtaining the high-quality oil-based needle coke.
The combination method provided by the invention can not only realize the refining of the oil slurry, make full use of the catalytic cracking oil slurry, but also obtain high-quality mesophase pitch, and simultaneously, the working procedures of preparing the mesophase pitch by the thermal polycondensation reaction and preparing the needle coke by the delayed coking reaction are respectively implemented in different devices, namely, the two working procedures realize decoupling, are not interfered with and influenced by each other, are more beneficial to industrial realization, also solve the problem of difficult control of the coking process in the production of the needle coke, and further obtain the high-quality needle coke product.
Description of the drawings: in the case where no particular definition is given, the expression of the content or m% used in the present invention is a mass percentage content.
The following embodiments are further provided to further explain the principles and effects of the present invention, but should not be construed as limiting the scope of the invention.
Example 1
The catalytic cracking slurry oil is used as a raw material, the properties of the slurry oil are shown in the following table 1, and the catalytic cracking slurry oil is implemented according to the flow shown in the figure 1.
The light hydrocarbon solvent consists of 75 m% of isobutane and 25 m% of normal butane, the pseudo-critical temperature is 139.4 ℃, catalytic slurry oil enters from the top of an extraction tower 1 (a sieve plate tower in the embodiment), the tower entering temperature is 120 ℃, the solvent is fed from the bottom of the extraction tower, the tower entering temperature is 80 ℃, the mass ratio of the solvent to the oil is 2.5:1, the pressure in the tower is 4.5MPa, the extraction solvent and the slurry oil raw material are in countercurrent contact for extraction, the formed extraction oil phase is fed from the top of the tower and enters a separation tower 2, the top temperature of the tower 1 is 86.2 ℃, and the raffinate phase is discharged from the bottom of the tower and is recovered as raffinate heavy components.
Table 1 example 1 slurry feedstock properties and extractive separation results
The separation tower 2 is an empty tower, the inlet temperature of the extraction oil phase is 150 ℃, the separation pressure in the tower is 4.35MPa, the extraction oil phase is separated into a light oil phase at the tower top and a heavy oil phase at the tower bottom, the light oil phase enters the supercritical solvent recovery tower 3, the pressure in the tower is controlled to be 4.25MPa, the temperature is 190 ℃, and the solvent density is 0.0847g/cm3The product containing a small amount of solvent obtained from the bottom is stripped to recover the solvent to become extracted light components, and the heavy oil phase at the bottom of the tower 3 is stripped to separate the solvent to obtain extracted intermediate components. As can be seen from the results of the separation in Table 1, the light fraction extracted was 15.0 m%, the middle fraction extracted was 60.1 m%, the impurity contents of the two fractions were significantly reduced, and the ash content thereof was significantly reduced<0.01 m%, asphaltene content<0.1 m%, a total metal content of about 1. mu.g/g, and an aromatic content of 54.09 m%.
The extracted intermediate component is taken as a preparation raw material of the intermediate phase asphalt and sent into a thermal polycondensation reactor 5, the thermal polycondensation reaction is carried out under the conditions of the temperature of 420 ℃, the time of 3h and the pressure of 1.5MPa to obtain the intermediate phase asphalt, and then the intermediate phase asphalt is sent into a coke tower to carry out the delayed coking reaction.
As shown in FIG. 1, coke drums 6 and 7 were alternately used, and one of them was decoked while the other was used in the coking reaction, that is, the obtained mesophase pitch was alternately fed to coke drums 6 and 7, and needle coke was prepared by delayed coking reaction under the coking reaction conditions of 490 ℃ of the feed temperature, 0.3MPa of the pressure, and 48 hours, and the obtained needle coke was calcined at 1300 ℃ to measure the thermal expansion Coefficient (CTE), true density, sulfur (S) content, volatile matter, ash content, resistivity, yield and the like, and the results are shown in Table 2.
TABLE 2 EXAMPLE 1 calcined needle coke Properties
Example 2
The properties of a certain catalytic cracking slurry oil are shown in Table 3, and the light hydrocarbon solvent comprises propane, isobutane and normal butane which respectively account for 25m percent and 50m percent% and 25 m%, the pseudo critical temperature is 127.0 ℃, the extraction and separation operation flow is the same as that of example 1, except that: the extraction tower 1 is a packed tower, the temperature of catalytic cracking slurry oil entering the top of the tower 1 is 100 ℃, the temperature of solvent entering the bottom of the tower 1 is 70 ℃, the mass ratio of solvent to oil is 3.5:1, the pressure in the tower 1 is 5.0MPa, and the temperature of the top of the extraction tower is 75.6 ℃; the separation tower 2 is a packed tower, the inlet temperature of the extraction oil phase is 135 ℃, and the pressure in the tower 2 is 4.8 MPa; the light oil phase enters a supercritical solvent recovery tower 3, the pressure in the tower 3 is controlled to be 4.7MPa, the temperature is controlled to be 180 ℃, and the solvent density is controlled to be 0.107g/cm3。
As can be seen from the extraction separation results in Table 3, the process according to the present example produced 20 m% of extracted light components and 47.8 m% of extracted intermediate components, and the separated extracted intermediate components had significantly removed impurities, with an ash content of <0.01 m%, an asphaltene content of <0.1 m%, a total metal content of about 4.3. mu.g/g, an aromatic content of 45.7 m%, and a sulfur content of 0.3 m%.
The obtained extracted intermediate component is used as a raw material for preparing the intermediate phase asphalt and is sent into a thermal polycondensation reactor 5, the thermal polycondensation reaction is carried out under the conditions of the temperature of 440 ℃, the time of 4 hours and the pressure of 1.0MPa to obtain the intermediate phase asphalt, and then the intermediate phase asphalt is sent into a coke tower to carry out the delayed coking reaction.
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the needle coke is prepared by delayed coking reaction under the conditions that the temperature of raw materials entering the coke towers is 495 ℃, the pressure is 0.7MPa and the time is 36h, the obtained needle coke is calcined at 1400 ℃, and the properties of the yield and the like are shown in table 4.
Table 3 example 3 slurry feedstock properties and extractive separation results
TABLE 4 EXAMPLE 2 calcined needle coke Properties
Example 3
The properties of a certain catalytic cracking slurry oil are shown in the following table 5, the light hydrocarbon solvent comprises 85m percent of n-butane and 15m percent of n-pentane respectively, and the pseudo-critical temperature is 149.5 ℃. The extraction and separation procedures were the same as in example 1, except that: the extraction tower 1 is a packed tower, the temperature of catalytic slurry oil entering the top of the tower 1 is 150 ℃, the temperature of solvent entering the bottom of the tower 1 is 120 ℃, the mass ratio of solvent to oil is 4.5:1, the pressure in the tower 1 is 6.0MPa, and the temperature of the top of the extraction tower is 124.5 ℃; the separation tower 2 is a sieve plate tower, the inlet temperature of the extraction oil phase is 175 ℃, and the pressure in the tower 2 is 5.8 MPa; the light oil phase enters a supercritical solvent recovery tower 3, the pressure in the tower 3 is controlled to be 5.6MPa, the temperature is controlled to be 210 ℃, and the solvent density is controlled to be 0.126g/cm3。
As can be seen from the extraction separation results in Table 5, the extracted light component obtained by the process of the present example is 15 m%, the intermediate component is 53.5 m%, and the separated extracted intermediate component is remarkably removed of impurities, wherein the ash content is 0.03 m%, the asphaltene content is 0.2 m%, the total metal content is less than 5 mu g/g, the aromatic content is 65.11 m%, and the sulfur content is 0.45 m%.
Directly using the obtained extracted intermediate component as an intermediate phase asphalt preparation raw material, sending the intermediate phase asphalt preparation raw material into a thermal polycondensation reactor 5, carrying out thermal polycondensation reaction under the conditions of 440 ℃, 4h and 1.0MPa to obtain intermediate phase asphalt, and sending the intermediate phase asphalt into a coke tower to carry out delayed coking reaction.
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the needle coke is prepared by delayed coking reaction under the conditions of the tower feeding temperature of 505 ℃, the pressure of 0.35MPa and the time of 18h, the obtained needle coke is calcined at 1420 ℃, and the properties of the yield and the like are shown in Table 6.
Table 5 example 3 slurry feedstock properties and extractive separation results
TABLE 6 EXAMPLE 3 calcined needle coke Properties
Example 4
The extracted light component obtained in example 3 and the extracted intermediate component are mixed according to the output mass ratio of 15.0:53.5, and are sent into a thermal polycondensation reactor 5 as an intermediate phase asphalt preparation raw material, the thermal polycondensation reaction is carried out under the conditions of the temperature of 430 ℃, the time of 6h and the pressure of 0.8MPa, the intermediate phase asphalt is obtained, and then the intermediate phase asphalt is sent into a coke tower to carry out the delayed coking reaction.
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the needle coke is prepared by delayed coking reaction under the conditions of the tower feeding temperature of 490 ℃, the pressure of 0.55MPa and the time of 16h, the obtained needle coke is calcined at 1350 ℃, and the properties of the yield and the like are shown in Table 7.
TABLE 7 EXAMPLE 4 calcined needle coke Properties
Example 5
The properties of a catalytic cracking slurry as a feedstock are shown in Table 8. The necessary hydrodesulfurization treatment was carried out according to the scheme shown in FIG. 1.
The light hydrocarbon solvent comprises 95 m%, 4 m% and 1 m% of normal butane, isobutane and normal pentane respectively, the pseudo critical temperature is 155.2 ℃, the extraction tower 1 is a packed tower, the catalytic slurry oil enters the top of the tower 1 at 160 ℃, the solvent enters the bottom of the tower 1 at 130 ℃, and the mass ratio of the solvent to the oil is4.5:1, the pressure in the tower 1 is 4.3MPa, and the temperature at the top of the extraction tower is measured to be 136.0 ℃; the separation tower 2 is a sieve plate tower, the inlet temperature of the extraction oil phase is 155 ℃, and the pressure in the tower 2 is 4.2 MPa; the light oil phase enters a supercritical solvent recovery tower 3, the pressure in the tower 3 is controlled to be 4.1MPa, the temperature is controlled to be 180 ℃, and the solvent density is controlled to be 0.113g/cm3The obtained tower top product contains a small amount of solvent, the extracted light component is obtained after the solvent is extracted through supercritical separation, and the extracted intermediate component is obtained after the heavy oil phase at the bottom of the separation tower 2 is subjected to steam stripping separation of the solvent.
As can be seen from the results of the extraction and separation in Table 8, the process according to this example produced 15.5 m% of the light fraction and 58.0% of the intermediate fraction. Feeding the obtained extracted intermediate component into hydrodesulfurization reactor 4, and using conventional residual oil hydrodesulfurization catalyst (gamma-Al)2O3Co and Mo are loaded, the pore volume is 0.4ml/g, the pore diameter is 7-13nm, and the specific surface is 150m2/g) carrying out hydrodesulfurization treatment, wherein the hydrotreating pressure is 6.0MPa, the volume ratio of hydrogen to oil is 600:1, and the space velocity is 1.0h-1Obtaining a hydrogenated product, distilling the hydrogenated product under normal pressure to collect hydrogenated tail oil with the boiling point higher than 350 ℃, discharging hydrogenated light fraction with the boiling point lower than 350 ℃ (the hydrogenated light fraction can be independently collected as a byproduct and can also be combined with reaction light components generated in the thermal polycondensation process to be discharged), and converting the yield of the hydrogenated tail oil into 49.8 m% of oil slurry (see table 8).
Mixing the extracted light components with hydrogenated tail oil according to a natural output ratio of 15.5:49.8, sending the mixture into a thermal polycondensation reactor 5, carrying out thermal polycondensation reaction at the temperature of 450 ℃, the time of 8 hours and the pressure of 2.0MPa to obtain mesophase pitch, and sending the mesophase pitch into a coke tower to carry out delayed coking reaction.
Table 8 example 5 slurry feed properties, extractive separation and hydrogenated tail oil results
TABLE 9 EXAMPLE 5 calcined needle coke Properties
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the raw material enters the coke towers at 510 ℃, the pressure of 0.45MPa and the time of 30h for delayed coking reaction to prepare needle coke, the obtained needle coke is calcined at 1350 ℃, and the properties of the yield and the like are shown in Table 9.
Example 6
The catalytic cracking slurry oil raw material, the extraction and separation operation and the hydrodesulfurization treatment are the same as those in example 5, but the hydrogenation product obtained by the hydrodesulfurization treatment has a distillate cut point of 420 ℃ during atmospheric and vacuum fractionation, and a hydrogenated tail oil fraction with a boiling point higher than 420 ℃ is obtained, wherein the yield accounts for 42.5 m% of the slurry oil raw material, and the specific reference is shown in Table 10.
Mixing the extracted light components with hydrogenated tail oil according to a natural output proportion of 15.5:42.5 by mass ratio, sending the mixture into a thermal polycondensation reactor 5, carrying out thermal polycondensation reaction at the reaction temperature of 420 ℃, the reaction time of 6h and the polycondensation pressure of 0.7MPa to obtain mesophase pitch, and sending the mesophase pitch into a coke tower to carry out delayed coking reaction.
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the delayed coking reaction is carried out on the raw materials at the tower inlet temperature of 500 ℃, the pressure of 0.7MPa and the time of 24h to prepare the needle coke, the obtained needle coke is calcined at 1450 ℃, and the properties of the yield and the like are shown in Table 11.
Table 10 example 6 hydrogenated tail oil results
TABLE 11 EXAMPLE 6 calcined needle coke Properties
Example 7
The properties of a certain catalytic cracking slurry as a raw material are shown in Table 12, and the light hydrocarbon solvent comprises 5m percent of n-butane, 3m percent of isobutane and 92m percent of n-pentane, and the pseudo-critical temperature of the catalyst is 191.7 ℃. The extraction tower 1 is a packed tower, the temperature of catalytic slurry oil entering the top of the tower 1 is 180 ℃, the temperature of solvent entering the bottom of the tower 1 is 150 ℃, the mass ratio of solvent to oil is 4.5:1, the pressure in the tower 1 is 4.0MPa, and the extraction solvent and the slurry oil raw material are in countercurrent contact to realize extraction; the extraction oil phase from the top of the tower enters a supercritical solvent recovery tower 3, extraction components are obtained after the extraction solvent is separated, the pressure in the tower 3 is controlled to be 3.7MPa, the temperature is controlled to be 230 ℃, and the solvent density is controlled to be 0.098g/cm3。
Table 12 example 7 slurry feed properties, extractive separation and hydrogenated tail oil results
TABLE 13 EXAMPLE 7 calcined needle coke Properties
As can be seen from the results of the extraction separation in Table 12, 65 m% of the extracted fraction was obtained according to the process of this example, and the obtained extracted fraction was fed to the hydrodesulfurization reactor 4 using a conventional residual oil hydrodesulfurization catalyst (. gamma. -Al)2O3The catalyst loaded with Ni and W metal active components has the pore volume of 0.45ml/g, the pore diameter range of 8-15nm and the specific surface of 200m2/g) carrying out hydrodesulfurization treatment, wherein the hydrotreating pressure is 10.0MPa, the volume ratio of hydrogen to oil is 800:1, and the space velocity is 0.6h-1Obtaining hydrogenated product, distilling the hydrogenated product to collect hydrogenated tail oil with boiling point higher than 350 ℃, and hydrogenatingThe yield of the tail oil accounts for 61.0m percent of the oil slurry.
The hydrogenated tail oil is used as a preparation raw material of the intermediate phase asphalt and is sent into a thermal polycondensation reactor 5, thermal polycondensation is carried out under the conditions of reaction temperature of 450 ℃, time of 2h and pressure of 1.5MPa, the intermediate phase asphalt is obtained, and then the intermediate phase asphalt is sent into a coke tower to carry out delayed coking reaction.
As shown in fig. 1, coke drums 6 and 7 were used alternately as in example 1. The obtained mesophase pitch is alternately sent into coke towers 6 and 7, the needle coke is prepared by delayed coking reaction under the conditions of the tower feeding temperature of 485 ℃, the pressure of 0.35MPa and the time of 24h, the obtained needle coke is calcined at 1300 ℃, and the properties of the yield and the like are shown in Table 13.
Claims (11)
1. A combined method for separating catalytic cracking slurry oil and preparing oil-based needle coke comprises the following steps:
the method comprises the steps of enabling a catalytic cracking oil slurry raw material to be in countercurrent contact with an extraction solvent in an extraction tower, enabling the extraction solvent to extract the catalytic cracking oil slurry under a supercritical or subcritical condition to form an extraction oil phase and a raffinate phase, sending the extraction oil phase into a separation tower, heating and separating the extraction oil phase into a light oil phase and a heavy oil phase, and recovering the extraction solvent from the raffinate phase to obtain a raffinate heavy component;
carrying out supercritical separation extraction on the light oil phase to obtain an extracted light component, and separating the heavy oil phase from the solvent to obtain an extracted intermediate component;
taking the extracted intermediate component or the mixture of the extracted intermediate component and the extracted light component as an intermediate phase asphalt preparation raw material, and carrying out thermal polycondensation reaction to prepare intermediate phase asphalt, wherein the mass content of the extracted light component in the mixture is not more than 50%;
preparing oil-based needle coke by using the obtained mesophase pitch and adopting a delayed coking technology;
wherein,
the components of the extraction solvent are C3-C5 light hydrocarbon fractions, and the pseudo-critical temperature Tc of the extraction solvent is between 90 and 196 ℃, and the pseudo-critical temperature Tc is expressed by the formulaTo obtain a compound of the formula wherein xiIs the molar fraction of component i, Tc, in the light hydrocarbon fractioniIs the critical temperature of the component i, n is the number of components contained in the extraction solvent,
feeding catalytic cracking slurry oil raw materials into a tower from the upper part of an extraction tower at the tower inlet temperature of 70-200 ℃, feeding an extraction solvent into the tower from the bottom of the extraction tower at the tower inlet temperature of 50-180 ℃, controlling the pressure of the extraction tower at 3.0-10.0MPa, and separating the extraction oil phase from the tower top and the raffinate phase from the tower bottom, wherein the mass ratio of the extraction solvent to the catalytic cracking slurry oil raw materials is 1.5-5.0: 1.
2. The combination method for separating catalytic cracking slurry oil and preparing oil-based needle coke as claimed in claim 1, wherein the mesophase pitch preparation material is subjected to thermal polycondensation to prepare mesophase pitch, the reaction pressure is 0.1-3.0MPa, the reaction temperature is 400-490 ℃, and the reaction time is 3-12 h.
3. The combined process for separating a catalytic cracking slurry oil and producing oil-based needle coke of claim 1, wherein the conditions of the delayed coking reaction are controlled as follows: the temperature of raw materials entering the tower is 480 ℃ and 510 ℃, the pressure is 0.1-1.0MPa, and the reaction time is 12-36 h.
4. The combined process for separating a catalytic cracking slurry oil and producing oil-based needle coke according to claim 2, wherein the conditions of the delayed coking reaction are controlled as follows: the temperature of raw materials entering the tower is 480 ℃ and 510 ℃, the pressure is 0.1-1.0MPa, and the reaction time is 12-36 h.
5. The combined method for separating catalytic cracking oil slurry and preparing oil-based needle coke according to claim 1, wherein the extracted oil phase is heated to 5-90 ℃ higher than the temperature of the top of the extraction tower, the temperature is fed into a separation tower, the separation pressure is controlled to be 3.0-10.0MPa, the heavy oil phase is discharged from the bottom of the tower, the extracted intermediate component is obtained after the solvent is separated, and the light oil phase is separated from the top of the tower, and the extracted light component is obtained by supercritical separation of the extraction solvent.
6. The combined process for separating catalytic cracking oil slurry and producing oil-based needle coke according to claim 1, wherein the supercritical separation of the extraction solvent is performed such that the density of the extraction solvent is less than 0.20g/cm3The separation pressure is 3.0-10.0MPa, and the separation temperature is controlled to be not higher than 280 ℃.
7. The combined process for separating catalytic cracking oil slurry and producing oil-based needle coke according to claim 5, wherein the supercritical separation of the extraction solvent is performed such that the density of the extraction solvent is less than 0.20g/cm3The separation pressure is 3.0-10.0MPa, and the separation temperature is controlled to be not higher than 280 ℃.
8. The combined process for separating catalytic cracking slurry oil and producing oil-based needle coke according to any one of claims 1 to 7, wherein the sulfur content of the catalytic cracking slurry oil raw material is not less than 0.5 m%, and the combined process further comprises:
the extracted intermediate component or the mixture of the extracted intermediate component and the extracted light component is subjected to hydrodesulfurization treatment, and the treated hydrogenated oil is fractionated to obtain hydrogenated light fractionThe cut point of the fraction is 350-450 ℃, the sulfur content of the hydrogenated tail oil with the boiling point higher than the cut point is less than or equal to 0.3m percent, and the density is 0.970g/cm3-1.050g/cm3The content of aromatic hydrocarbon is 40-65 m%;
the hydrogenated tail oil or the mixture of the hydrogenated tail oil and the extracted light components is used as a raw material for preparing the mesophase pitch, and the mass content of the extracted light components in the mixture is not more than 40%.
9. The combined process for separating catalytic cracking slurry oil and producing oil-based needle coke as claimed in claim 8, wherein the hydrodesulfurization process uses a residual oil hydrodesulfurization catalyst, the hydrotreating pressure is 6-16MPa, the hydrogen-oil volume ratio is 200:1-1200:1, and the space velocity is 0.2-2.0h-1。
10. The combined process for separating catalytically cracked slurry oil and producing oil-based needle coke as claimed in claim 1, wherein the catalytically cracked slurry oil has a density of 0.970g/cm3-1.200g/cm3Carbon residue<21.0 m%, C7 asphaltene content<10.0 m%, ash content<3.0 m%, sulfur content<3.0m％。
11. The combined process for separating catalytic cracking slurry oil and producing oil-based needle coke of claim 1, wherein the density of the obtained mesophase pitch production feedstock is 0.970-1.1g/cm3Aromatic hydrocarbon content of 40-65 m%, sulfur content<0.4m％。
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| CN112812802B (en) * | 2021-01-13 | 2022-04-15 | 中国石油大学(华东) | Continuous process for preparing mesophase pitch by refining raw oil |
| CN115216335A (en) * | 2021-04-14 | 2022-10-21 | 张家港保税区慧鑫化工科技有限公司 | Needle coke production process |
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