Resource utilization method of ethylene tar

Abstract

The invention provides a resource utilization method of ethylene tar, which is characterized in that phosphoric acid is added into the ethylene tar, and then light fractions and heavy fractions in different temperature intervals are respectively obtained in a reduced pressure distillation manner, so that the yield of light components and the carbon yield in a carbonization stage are increased; meanwhile, sulfur, nitrogen and metal elements in the ethylene tar can be transferred to the heavy fraction, so that the light fraction has fewer impurities and is purer. The method provided by the invention can recycle all fractions of the ethylene tar, improves the overall utilization rate of ethylene tar resources, and has the advantages of economy and environmental protection.

Description

Technical Field

[0001] The invention belongs to the field of petrochemical industry, and specifically relates to a resource utilization method of ethylene tar. Background Art

[0002] Ethylene tar (ET) is a by-product of the ethylene production process, and its output is increasing year by year. ET has a complex composition, mainly composed of C and H elements, and a high asphaltene content. Most of it is used as boiler fuel in China, resulting in a waste of resources and low economic benefits. In addition, a large amount of black smoke is produced during the combustion process, polluting the environment. How to improve the clean and efficient use of ethylene tar resources determines the overall benefits of ethylene plants, and is also one of the issues that need to be addressed in the current research on ethylene tar at home and abroad.

[0003] Ethylene tar has good application prospects in carbon materials, and there are many studies in this direction. Patent CN117658128A fractionates ethylene tar (ET) to obtain a fraction of 250-550°C, performs hydrogenation treatment, pre-carbonizes part of the hydrogenated ET to obtain coke, mixes the remaining hydrogenated ET and the coke to form a mixture, and then performs activation treatment to obtain porous carbon. The porous carbon prepared above has high purity and good stability, but this method has a complicated process, and only takes the fraction with a fraction section of 250-550°C, and the other fractions cannot be fully utilized. The use of hydrogenation treatment leads to high production costs. Patent CN106672966A dissolves ethylene tar in n-heptane, refluxes, filters, and pre-oxidizes the filter cake to obtain a precursor of a porous carbon material. A chemically synthesized in-situ template and the precursor are co-carbonized to prepare porous carbon. The template method compensates for the wider pore size distribution formed by alkali activation. The template agent is easy to remove. After acid washing, the template agent can be regenerated, thereby realizing the recycling of materials. However, the ethylene tar is pre-treated with n-heptane to remove the light components, which makes it impossible to fully utilize the light components, resulting in a waste of resources.

[0004] It can be seen that when using ethylene tar (ET) as a raw material to prepare carbon materials, most of them only select some of the fractions, resulting in the inability to fully utilize other fractions, causing a waste of resources. In addition, in the activation stage, KOH is used as an activator, which is costly, and a large amount of alkali input causes serious corrosion of the equipment, and impurities are difficult to remove; affecting the specific surface area and pore size distribution of the carbon material. At the same time, the light components obtained by the current common methods have high sulfur, nitrogen and metal contents, which also affects their next step of utilization. Summary of the invention

[0005] Based on the above-mentioned background technology, the present invention provides a method for resource utilization of ethylene tar, which adds phosphoric acid to ethylene tar (ET), and then obtains light fractions and heavy fractions in different temperature ranges by vacuum distillation, thereby increasing the yield of light components and the carbon yield in the carbonization stage, and at the same time, it can realize the transfer of sulfur, nitrogen and metal elements in ethylene tar to heavy fractions, thereby making the light fractions have fewer impurities and purer. The method of the present invention can recycle all fractions of ethylene tar, improve the overall utilization rate of ethylene tar resources, and has the advantages of economy and environmental protection.

[0006] In order to achieve the purpose of the invention, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for resource utilization of ethylene tar, comprising the following steps:

[0008] (1) Ethylene tar is mixed with phosphoric acid and then heated to perform vacuum distillation;

[0009] (2) Separating to obtain a light fraction of ≤85°C, a naphthalene-containing fraction of >85°C and ≤101°C, a methylnaphthalene-containing fraction of >101°C and ≤117.5°C, a fraction of >117.5°C and ≤210°C, and a heavy fraction of >210°C.

[0010] In the present invention, the ethylene tar in step (1) is a high-temperature condensation byproduct obtained by high-temperature cracking of hydrocarbon raw materials such as straight-run coal diesel or naphtha in the production of ethylene, and mainly contains components such as naphthalene and methylnaphthalene. The present invention has no special requirements for its source and composition; preferably, based on the weight percentage of the ethylene tar as 100%, its elemental composition includes: 85-95wt% (for example, 85wt%, 87wt%, 89wt%, 90wt%, 91wt%, 93wt%, 95wt%, etc.), H 5-15wt% (e.g., 5wt%, 7wt%, 9wt%, 10wt%, 11wt%, 13wt%, 15wt%, etc.), sulfur ≤0.7wt% (e.g., 0.6wt%, 0.5wt%, 0.4wt%, 0.3wt%, 0.2wt%, 0.1wt%, 0.05wt%, etc.), nitrogen ≤1wt% (e.g., 1wt%, 0.9wt%, 0.8wt%, 0.7wt%, 0.6wt%, 0.5wt%, 0.4wt%, 0.3wt%, 0.2wt%, 0.1wt%, etc.), metal elements ≤120ppm (e.g., 120ppm, 100ppm, 80ppm, 60ppm, 50ppm, 40ppm, etc.);

[0011] Among them, metal elements are introduced from cracking oil raw materials, cracking equipment, etc., mainly including iron, nickel, manganese, vanadium, etc.;

[0012] Among them, the main compounds of C and H elements exist in the form of aromatic hydrocarbons, including naphthalene and methylnaphthalene, and the rest are long-chain alkanes, cycloalkanes, etc.; preferably, based on the weight percentage of the ethylene tar as 100%, it includes: 20-50wt% of naphthalene (for example, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, etc.), 10-30wt% of methylnaphthalene (for example, 10wt%, 13wt%, 15wt%, 18wt%, 20wt%, 23wt%, 25wt%, 28wt%, 30wt%, etc.).

[0013] In the present invention, the amount of phosphoric acid added in step (1) is 10-40% of the mass of ethylene tar, for example, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, etc., preferably 40wt%.

[0014] In the present invention, step (1) heats ethylene tar for vacuum distillation, wherein the vacuum distillation is carried out by using a vacuum pump to maintain a negative pressure of -0.5 to -0.05 MPa, such as -0.5 MPa, -0.3 MPa, -0.1 MPa, -0.05 MPa, -0.01 MPa, etc.;

[0015] Preferably, the reduced pressure distillation has a heating rate of 1 to 4°C / min, such as 1°C / min, 2°C / min, 3°C / min, 4°C / min, etc.

[0016] In the present invention, the light fraction of ≤85°C in step (2) comprises: 35-50% (e.g. 35wt%, 37wt%, 39wt%, 40wt%, 42wt%, 44wt%, 46wt%, 48wt%, 50wt%, etc.) of straight-chain alkanes (e.g. n-hexane, n-heptane), 20-35% (e.g. 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, 31wt%, 33wt%, 35wt%, etc.) of cycloalkanes (e.g. methylcyclohexane, cyclohexane, etc.), 15-30% (e.g. 15wt%, 17wt%, 19wt%, 20wt%, etc.) of aromatic hydrocarbons (e.g. toluene, xylene, etc.). t%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt%, etc.), sulfur<0.02wt% (e.g., 0.019wt%, 0.017wt%, 0.015wt%, 0.012wt%, 0.010wt%, 0.007wt%, 0.005wt%, 0.001wt%, etc.), nitrogen<0.02wt% (e.g., 0.019wt%, 0.017wt%, 0.015wt%, 0.012wt%, 0.010wt%, 0.007wt%, 0.005wt%, 0.001wt%, etc.), metal elements<3ppm (e.g., 2ppm, 1ppm, and not detected, etc.);

[0017] The naphthalene-containing fraction with a temperature of more than 85° C. and less than 101° C. comprises, in weight percentage, 50-70wt% (e.g., 50wt%, 53wt%, 55wt%, 58wt%, 60wt%, 63wt%, 65wt%, 68wt%, 70wt%, etc.) of naphthalene, 0-2wt% (e.g., 0wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.3wt%, 1.5wt%, 1.8wt%, 2.0wt%, etc.) of methylnaphthalene, and less than 0.04wt% (e.g., 0.039wt%, 0.035wt%) of sulfur. t%, 0.030wt%, 0.025wt%, 0.020wt%, 0.015wt%, 0.010wt%, 0.005wt%, 0.001wt%, etc.), nitrogen<0.05wt% (for example, 0.049wt%, 0.04wt%, 0.03wt%, 0.02wt%, 0.01wt%, 0.005wt%, 0.001wt%, etc.), metal elements<6ppm (for example, 5ppm, 4ppm, 3ppm, 2ppm, 1ppm, and undetected, etc.), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons, etc.;

[0018] The methylnaphthalene fraction with a temperature of more than 101° C. and less than 117.5° C. comprises, by weight percentage, 2-6wt% (e.g., 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, etc.) of naphthalene, 75-85wt% (e.g., 75wt%, 77wt%, 79wt%, 81wt%, 83wt%, 85wt%, etc.) of methylnaphthalene, and less than 0.08wt% (e.g., 0.079wt%, 0.07wt%, 0.06wt%, 0.05wt%, 0.04wt%, 0.03wt%, 0.02wt%, 0.0 1wt%, 0.005wt%, 0.001wt%, etc.), nitrogen <0.08wt% (for example, 0.079wt%, 0.07wt%, 0.06wt%, 0.05wt%, 0.04wt%, 0.03wt%, 0.02wt%, 0.01wt%, 0.005wt%, 0.001wt%, etc.), metal elements <10ppm (for example, 8ppm, 7ppm, 6ppm, 5ppm, 4ppm, 3ppm, 2ppm, 1ppm, and undetected, etc.), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons;

[0019] The fraction with a temperature of more than 117.5° C. and less than 210° C. has a weight percentage composition comprising sulfur less than 0.1wt% (e.g., 0.09wt%, 0.07wt%, 0.05wt%, 0.01wt%, etc.), nitrogen less than 0.1wt% (e.g., 0.09wt%, 0.07wt%, 0.05wt%, 0.01wt%, etc.), metal elements less than 15ppm (e.g., 15ppm, 13ppm, 11ppm, 9ppm, 7ppm, 5ppm, 3ppm, 1ppm, and undetected), and the rest are alkanes, cycloalkanes, polycyclic aromatic hydrocarbons (including phenanthrene, anthracene, etc.), etc.;

[0020] The heavy fraction with a temperature of more than 210° C. comprises, by weight percentage, 35 to 50% (e.g., 35wt%, 37wt%, 39wt%, 40wt%, 42wt%, 44wt%, 46wt%, 48wt%, 50wt%) of polycyclic aromatic hydrocarbons (including methyl anthracene, pyrene, etc.), sulfur less than 0.65wt% (e.g., 0.63wt%, 0.5wt%, 0.4wt%, 0.3wt%, 0.2wt%, 0.1wt%, 0.05wt%) of sulfur, and 100wt% (e.g., 100wt%, ... wt%, 0.01wt%, etc.), nitrogen <0.9wt% (for example, 0.74wt%, 0.7wt%, 0.5wt%, 0.3wt%, 0.1wt%, 0.05wt%, 0.01wt%, etc.), metal elements <95ppm (for example, 89ppm, 80ppm, 60ppm, 40ppm, 20ppm, 10ppm, 5ppm, 1ppm, and undetected, etc.), and the rest are impurities (for example, gum, asphaltenes).

[0021] In a preferred embodiment of the present invention, step (3) is optionally included, in which CO2 gas is used as an activating agent to perform high-temperature carbonization on the heavy fraction with a temperature > 210°C separated in step (2) to obtain activated carbon.

[0022] Preferably, the high-temperature carbonization operation is carried out in a tubular furnace, the carbonization temperature is 700-900°C, for example, 700°C, 750°C, 800°C, 850°C, 900°C, etc.; the carbonization time is 1-4h, for example, 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, etc.;

[0023] Preferably, the heating rate is 5 to 10°C / min, for example, 5°C / min, 6°C / min, 7°C / min, 8°C / min, 9°C / min, 10°C / min, etc.;

[0024] Preferably, the feed flow rate of the CO2 gas is 0.5-2 L / min, for example 0.5 L / min, 0.7 L / min, 1 L / min, 1.3 L / min, 1.5 L / min, 1.8 L / min, 2 L / min, etc., where the feed flow rate refers to the amount of CO2 gas flowing through a unit cross-section of the tubular furnace per unit time.

[0025] The activated carbon obtained has an activated carbon yield of >58wt% calculated based on the total mass of the heavy fraction at >210°C.

[0026] The activated carbon obtained has the following characteristic parameters: specific surface area (BET)>700m 2 / g; total pores>0.029cm3 / g; micropores>0.019cm 3 / g; it also has the advantages of large specific surface area and high porosity, and can be used in waste gas treatment, water treatment and other fields.

[0027] In a preferred embodiment of the present invention, the process further optionally comprises step (4), which comprises mixing at least one of the light fraction of ≤85°C and the fraction of >117.5°C and ≤210°C separated in step (2) with a complexing agent for reaction, and then rectifying to obtain a diesel blending component. It should be noted that the optional step (4) and the optional step (3) described above have no order of precedence, and may only comprise step (4) or step (3), or may simultaneously employ the operations of step (4) and step (3).

[0028] Preferably, the complexing agent is selected from at least one of molecular sieves, ethylenediaminetetraacetic acid (EDTA), phosphate complexing agents, and thiol complexing agents, preferably at least one of modified ZSM-5 molecular sieves and thiol complexing agents, and more preferably Na / ZSM-5 molecular sieves;

[0029] Preferably, the complexing agent is added in an amount of 0.01-2wt%, for example 0.05wt%, 0.1wt%, 1wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2wt%, etc., based on the total mass of the light fraction ≤85°C and the fraction >117.5°C and ≤210°C.

[0030] Preferably, the complexation reaction is carried out at a temperature of 40 to 70°C, such as 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, etc., and for a time of 0.5 to 3h, such as 0.5h, 1h, 1.5h, 2h, 2.5h, 3h, etc.;

[0031] The distillation temperature is 50-100°C, for example, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc.

[0032] The diesel blending component obtained comprises: 80-95wt% (e.g., 80wt%, 83wt%, 85wt%, 88wt%, 90wt%, 93wt%, 95wt%) of alkanes and cycloalkanes, sulfur <2ppm (e.g., 1ppm, and not detected), nitrogen <2ppm (e.g., 1ppm, and not detected), metal elements <2ppm (e.g., 1ppm, and not detected), and the rest are aromatics;

[0033] The diesel blending component prepared by the present invention has a yield of 50-60% based on the total mass of the light fraction ≤85°C and the fraction >117.5°C and ≤210°C; the diesel blending component has the advantages of low sulfur, low nitrogen, low metal, etc., and can be used as a diesel additive component to improve the low-temperature fluidity of diesel.

[0034] In a preferred embodiment of the present invention, the naphthalene-containing fraction with a temperature of >85°C and ≤101°C and the methylnaphthalene-containing fraction with a temperature of >101°C and ≤117.5°C are respectively treated by rectification to obtain naphthalene and methylnaphthalene products. The rectification is a conventional operation in the art and has no special requirements.

[0035] The naphthalene product prepared by the invention has a yield of 55-65% and a purity of more than 96%, calculated based on the total mass of the naphthalene-containing fraction with a temperature greater than 85° C. and less than 101° C., and can be directly used as a crude naphthalene product.

[0036] The methylnaphthalene product prepared by the present invention has a yield of 65-75% and a purity of 90-95% based on the total mass of the methylnaphthalene-containing fraction with a temperature greater than 101° C. and less than 117.5° C., and can be applied to organic synthesis intermediates, etc.

[0037] Through the resource utilization method of ethylene tar of the present invention, the yield of light components is above 30wt%, wherein the light components are all fractions ≤210°C, including the light fraction ≤85°C in step 2), the naphthalene-containing fraction >85°C and ≤101°C, the methylnaphthalene-containing fraction >101°C and ≤117.5°C, and the fraction >117.5°C and ≤210°C; the yield of the light components is calculated based on the total mass of ethylene tar;

[0038] In the light components, in each fraction, the S content is less than 0.1wt%, the N content is less than 0.1wt%, and the metal element content is less than 15ppm;

[0039] In the light component, the desulfurization rate of the light component is >80wt%, the denitrification rate is >80wt%, and the demetallization rate is >85wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0040] Compared with the prior art, the advantages and positive effects of the present invention are:

[0041] 1. In the current method of making carbon from ethylene tar, since ethylene tar contains light components such as saturated components and aromatic components, the presence of light components will escape during the carbonization stage, thereby causing the collapse of the pore wall and reducing the carbonization yield. The present invention firstly performs a vacuum distillation treatment on the ethylene tar and then carbonizes it, which not only solves the above-mentioned problem, but also increases the yield of light components and the carbon yield in the carbonization stage.

[0042] 2. The present invention introduces oxygen and phosphorus atoms by adding phosphoric acid to form a cross-linked structure, thereby increasing the softening point of the molecules in ET, and thereby preventing the rearrangement of the molecules in the heavy fraction of ET during the carbonization process, inhibiting the orientation of the molecules in the heavy fraction of ET, thereby reducing the crystallinity during the carbonization process, increasing the reactivity between the molecules in the heavy fraction of ET and the activator (carbon dioxide), forming micropores, and preparing activated carbon with a special high surface area. The addition of phosphoric acid also simultaneously realizes the transfer of sulfur, nitrogen and metal elements in ethylene tar to the heavy fraction, thereby making the light fraction less impurities and more pure.

[0043] 3. In the method of the present invention, all fractions of ethylene tar can be fully utilized, thereby increasing the overall utilization rate of ethylene tar resources. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the embodiments and comparative examples of the present invention, the sources of the main raw materials used are as follows. Unless otherwise specified, other raw materials and reagents were purchased from commercial sources:

[0046] Phosphoric acid: Inokane, ≥85wt%;

[0047] Naphthalene: Inokane, 99%;

[0048] 1-Methylnaphthalene: Inokene, ≥97%;

[0049] Na / ZSM-5: Kramar;

[0050] Ethylene tar: derived from Wanhua ethylene plant, including the element composition shown in Table 1 below, wherein the naphthalene content is 36.5wt% and the methylnaphthalene content is 18.5wt%;

[0051] Table 1 Ethylene tar composition

[0052] C (wt%) H (wt%) S (wt%) N (wt%) Metal elements (Fe+Ni) (ppm) 87.1 11.2 0.665 0.932 98

[0053] The main analytical methods used in the examples and comparative examples of the present invention are:

[0054] Carbon yield: weigh the heavy distillate oil > 210℃, record the mass M1, and obtain the carbon mass after carbonization reaction, record it as M2, carbon yield = M2 / M1;

[0055] Naphthalene, methylnaphthalene: gas chromatography-mass spectrometry, equipment model Agilent 8890B-5977B;

[0056] BET and pore size: measured according to GB / T 19587-2017;

[0057] Metal elements: ICP-OES, equipment model Agilent 5900;

[0058] Sulfur and nitrogen elements: element analyzer, equipment model, Jena Muti EA 5000.

[0059] Example 1

[0060] (1) Weigh 200 g of ethylene tar, add 20 g of phosphoric acid, stir evenly, set the heating rate to 1°C / min, and turn on the vacuum pump to maintain a negative pressure of -0.1 MPa.

[0061] (2) The light fraction (A) of ≤85°C, the naphthalene-containing fraction (B) of >85°C and ≤101°C, the methylnaphthalene-containing fraction (C) of >101°C and ≤117.5°C, the fraction (D) of >117.5°C and ≤210°C, and the heavy fraction (E) of >210°C were sequentially collected to a temperature of 350°C for a total of 5 hours. The proportion of each fraction based on the total mass of ethylene tar is shown in Table 2 below.

[0062] Table 2

[0063] A B C D E Proportion / wt% 1.6 23.5 10.05 0.5 64.35

[0064] Among them, the light fraction (A) ≤85°C has a weight percentage composition including: 38.5% straight-chain alkanes (including n-heptane, n-hexane, etc.), 33.2% cycloalkanes (including cyclohexane, methylcyclohexane, etc.), 28.2% aromatics (including toluene, xylene, etc.); and 0.01wt% sulfur, 0.015wt% nitrogen, and a total content of metal elements (Fe+Ni) of 1ppm.

[0065] The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C comprises 54.5wt% naphthalene, 1.2wt% methylnaphthalene, 0.015wt% sulfur, 0.032wt% nitrogen, 2ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0066] The methylnaphthalene fraction (C) with a temperature of >101°C and ≤117.5°C comprises 3.4wt% naphthalene, 78.5wt% methylnaphthalene, 0.031wt% sulfur, 0.054wt% nitrogen, 4ppm total metal elements (Fe+Ni), and the remainder being alkanes, cycloalkanes and other aromatic hydrocarbons.

[0067] The fraction (D) with a temperature of >117.5°C and ≤210°C has a weight percentage composition of: 0.088wt% sulfur, 0.091wt% nitrogen, 7ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes, polycyclic aromatic hydrocarbons (including phenanthrene, anthracene, etc.).

[0068] The heavy fraction (E) at >210°C has a weight percentage composition of: 48.6wt% polycyclic aromatic hydrocarbons (including methylanthracene, pyrene, etc.); 0.55wt% sulfur, 0.75wt% nitrogen, 85ppm total metal element (Fe+Ni), and the rest are impurities (including colloids, asphaltene, etc.).

[0069] The total yield of the light component (fraction AD) is 36.35wt%; among the light components, the desulfurization rate of the light components is 82.7wt%, the denitrification rate is 80.5wt%, and the demetallization rate is 86.7wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0070] (3) The heavy fraction (E) with a temperature of >210°C is placed in a tubular furnace, CO2 gas is used as an activator, the feed flow rate is 0.6 L / min, the carbonization temperature is 800°C, the carbonization time is 3 h, and the heating rate is 5°C / min to obtain activated carbon having the following characteristic parameters:

[0071] BET: 798.4m 2 / g, total pores: 0.13 cm3 / g, micropores: 0.10 cm3 / g, carbon yield: 58.5wt%.

[0072] (4) A light fraction (A) of ≤85°C and a fraction (D) of >117.5°C and ≤210°C are mixed, 0.2 wt% of a complexing agent Na / ZSM-5 is added thereto for reaction at a temperature of 50°C for 1 h, and then distilled at 80°C to obtain a diesel blending component, the weight percentage composition of which includes: 85.5% long-chain alkanes and cycloalkanes, 1 ppm sulfur, 1 ppm nitrogen, 1 ppm metal elements (Fe+Ni), and the rest are aromatic hydrocarbons; the yield is 52.5% based on the total mass of fractions A and D.

[0073] (5) The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C is separated by rectification to obtain a naphthalene product with a purity of 96.5%. The yield calculated based on the mass of fraction B is 63.5%.

[0074] The methylnaphthalene-containing fraction (C) with a temperature of >101°C and ≤117.5°C is separated by rectification to obtain a methylnaphthalene product with a purity of 93.5%. The yield calculated based on the mass of fraction C is 66.5%.

[0075] Example 2

[0076] (1) Weigh 200 g of ethylene tar, add 40 g of phosphoric acid, stir evenly, set the heating rate to 2°C / min, and turn on the vacuum pump to maintain a negative pressure of -0.1 MPa.

[0077] (2) The light fraction (A) of ≤85°C, the naphthalene-containing fraction (B) of >85°C and ≤101°C, the methylnaphthalene-containing fraction (C) of >101°C and ≤117.5°C, the fraction (D) of >117.5°C and ≤210°C, and the heavy fraction (E) of >210°C were sequentially collected to a temperature of 380°C for a total of 8 hours. The proportion of each fraction based on the total mass of ethylene tar is shown in Table 3 below.

[0078] Table 3

[0079] A B C D E Proportion / wt% 1.65 24.5 12.0 5.5 56.35

[0080] Among them, the light fraction (A) ≤85°C has a weight percentage composition including: 39.5% straight-chain alkanes (including n-hexane, n-heptane, etc.), 34.4% cycloalkanes (including cyclohexane, methylcyclohexane, etc.), 25.9% aromatics (including toluene, xylene, etc.); and 0.009wt% sulfur, 0.012wt% nitrogen, and a total content of metal elements (Fe+Ni) of 1ppm.

[0081] The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C comprises 56.2wt% naphthalene, 1.4wt% methylnaphthalene, 0.011wt% sulfur, 0.025wt% nitrogen, 2ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0082] The methylnaphthalene fraction (C) with a temperature of >101°C and ≤117.5°C comprises 2.4wt% naphthalene, 79.2wt% methylnaphthalene, 0.017wt% sulfur, 0.024wt% nitrogen, 3ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0083] The fraction (D) with a temperature of >117.5°C and ≤210°C has a weight percentage composition of: 0.028wt% sulfur, 0.048wt% nitrogen, 5ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes, polycyclic aromatic hydrocarbons (including phenanthrene, anthracene, etc.).

[0084] The heavy fraction (E) at >210°C has a weight percentage composition of: polycyclic aromatic hydrocarbons (including methylanthracene, pyrene, etc.) 49.4wt%; sulfur 0.60wt%, nitrogen 0.83wt%, a total metal element (Fe+Ni) content of 88ppm, and the rest are impurities (including colloids, asphaltene, etc.).

[0085] The total yield of the light component (fraction AD) is 43.65wt%; among the light components, the desulfurization rate of the light components is 90.2wt%, the denitrification rate is 89.1wt%, and the demetallization rate is 89.8wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0086] (3) The heavy fraction (E) with a temperature of >210°C is placed in a tube furnace, CO2 gas is used as an activator, the feed flow rate is 0.8 L / min, the carbonization temperature is 700°C, the carbonization time is 3 h, and the heating rate is 5°C / min to obtain activated carbon having the following characteristic parameters:

[0087] BET:1025.3m2 / g, total pore size: 0.37cm 3 / g, micropore: 0.35cm 3 / g, carbon yield: 62.1wt%.

[0088] (4) A light fraction (A) ≤85°C and a fraction (D) >117.5°C and ≤210°C are mixed, 0.3 wt% of a complexing agent Na / ZSM-5 is added thereto for reaction at a temperature of 53°C for 1.5 h, and then distilled at 80°C to obtain a diesel blending component, the weight percentage composition of which includes: 88.5% long-chain alkanes and cycloalkanes, 1 ppm sulfur, 1 ppm nitrogen, 1 ppm metal elements (Fe+Ni), and the rest are aromatic hydrocarbons; the yield is 55.2% based on the total mass of fractions A and D.

[0089] (5) The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C is separated by rectification to obtain a naphthalene product with a purity of 96.8%. The yield calculated based on the mass of fraction B is 64.5%.

[0090] The methylnaphthalene-containing fraction (C) with a temperature of >101°C and ≤117.5°C is separated by rectification to obtain a methylnaphthalene product with a purity of 94.1%. The yield calculated based on the mass of fraction C is 67.2%.

[0091] Example 3

[0092] (1) Weigh 200 g of ethylene tar, add 60 g of phosphoric acid, stir evenly, set the heating rate to 3°C / min, and turn on the vacuum pump to maintain a negative pressure of -0.1 MPa.

[0093] (2) The light fraction (A) of ≤85°C, the naphthalene-containing fraction (B) of >85°C and ≤101°C, the methylnaphthalene-containing fraction (C) of >101°C and ≤117.5°C, the fraction (D) of >117.5°C and ≤210°C, and the heavy fraction (E) of >210°C were sequentially collected to a temperature of 430°C for a total of 8 hours. The proportion of each fraction based on the total mass of ethylene tar is shown in Table 4 below.

[0094] Table 4

[0095] A B C D E Proportion / wt% 1.65 24 12.0 13.1 49.25

[0096] Among them, the light fraction (A) ≤85°C has the following weight percentage compositions: 39.5% straight-chain alkanes (including n-hexane, n-heptane, etc.), 34.2% cycloalkanes (including cyclohexane, methylcyclohexane, etc.), 26.1% aromatics (including toluene, xylene, etc.); and 0.008wt% sulfur, 0.01wt% nitrogen, and the total content of metal elements (Fe+Ni) <1ppm.

[0097] The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C comprises 57.1wt% naphthalene, 1.3wt% methylnaphthalene, 0.009wt% sulfur, 0.012wt% nitrogen, 1ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0098] The methylnaphthalene fraction (C) with a temperature of >101°C and ≤117.5°C comprises 2.2wt% naphthalene, 79.3wt% methylnaphthalene, 0.01wt% sulfur, 0.015wt% nitrogen, 1ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0099] The fraction (D) with a temperature of >117.5°C and ≤210°C has a weight percentage composition of 0.015wt% sulfur, 0.018wt% nitrogen, 2ppm total metal element (Fe+Ni), and the rest mainly polycyclic aromatic hydrocarbons.

[0100] The heavy fraction (E) at >210°C has a weight percentage composition of: polycyclic aromatic hydrocarbons (including methylanthracene, pyrene, etc.) 48.4wt%; sulfur 0.623wt%, nitrogen 0.877wt%, a total metal element (Fe+Ni) content of 94ppm, and the rest are impurities (including colloids, asphaltene, etc.).

[0101] The total yield of the light component (fraction AD) is 50.75wt%; among the light components, the desulfurization rate of the light components is 93.7wt%, the denitrogenation rate is 94.1wt%, and the metal element removal rate is 95.9wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0102] (3) The heavy fraction (E) with a temperature of >210°C is placed in a tube furnace, CO2 gas is used as an activator, the feed flow rate is 1.0 L / min, the carbonization temperature is 900°C, the carbonization time is 1 h, and the heating rate is 5°C / min to obtain activated carbon having the following characteristic parameters:

[0103] BET:1156.5m 2 / g, total pore size: 0.41cm 3 / g, micropore: 0.40cm 3 / g, carbon yield: 65.6wt%.

[0104] (4) A light fraction (A) ≤85°C and a fraction (D) >117.5°C and ≤210°C are mixed, 0.5 wt% of a complexing agent Na / ZSM-5 is added thereto for reaction at a temperature of 55°C for 2 hours, and then distilled at 80°C to obtain a diesel blending component, the weight percentage composition of which includes: 89.3% long-chain alkanes and cycloalkanes, undetectable sulfur, undetectable nitrogen, 1 ppm of metal elements (Fe+Ni), and the rest are aromatic hydrocarbons; the yield is 56.3% based on the total mass of fractions A and D.

[0105] (5) The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C is separated by rectification to obtain a naphthalene product with a purity of 96.8%. The yield calculated based on the mass of fraction B is 64.6%.

[0106] The methylnaphthalene-containing fraction (C) with a temperature of >101°C and ≤117.5°C is separated by rectification to obtain a methylnaphthalene product with a purity of 94.3%. The yield calculated based on the mass of fraction C is 67.2%.

[0107] Example 4

[0108] (1) Weigh 200 g of ethylene tar, add 70 g of phosphoric acid, stir evenly, set the heating rate to 4 °C / min, and turn on the vacuum pump to maintain a negative pressure of -0.1 MPa.

[0109] (2) The light fraction (A) of ≤85°C, the naphthalene-containing fraction (B) of >85°C and ≤101°C, the methylnaphthalene-containing fraction (C) of >101°C and ≤117.5°C, the fraction (D) of >117.5°C and ≤210°C, and the heavy fraction (E) of >210°C were sequentially collected to a temperature of 480°C for a total of 8 hours. The proportion of each fraction based on the total mass of ethylene tar is shown in Table 5 below.

[0110] Table 5

[0111] A B C D E Proportion / wt% 1.6 24 12.8 20.1 41.5

[0112] Among them, the light fraction (A) ≤85°C has a weight percentage composition including: 39.3% straight-chain alkanes (including n-hexane, n-heptane, etc.), 34.4% cycloalkanes (including cyclohexane, methylcyclohexane, etc.), 26.2% aromatics (including toluene, xylene, etc.); and 0.005wt% sulfur, 0.007wt% nitrogen, and a total content of metal elements (Fe+Ni) <1ppm.

[0113] The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C comprises 57.3wt% naphthalene, 1.4wt% methylnaphthalene, 0.007wt% sulfur, 0.009wt% nitrogen, a total content of metal elements (Fe+Ni) <1ppm, and the rest being alkanes, cycloalkanes and other aromatic hydrocarbons.

[0114] The methylnaphthalene fraction (C) with a temperature of >101°C and ≤117.5°C comprises 2.1wt% naphthalene, 79.4wt% methylnaphthalene, 0.008wt% sulfur, 0.011wt% nitrogen, 1ppm total metal element (Fe+Ni), and the rest being alkanes, cycloalkanes and other aromatic hydrocarbons.

[0115] The fraction (D) with a temperature of >117.5°C and ≤210°C has a weight percentage composition of 0.010wt% sulfur, 0.013wt% nitrogen, 2ppm total metal element (Fe+Ni), and the rest mainly polycyclic aromatic hydrocarbons.

[0116] The heavy fraction (E) at >210°C has a weight percentage composition of: polycyclic aromatic hydrocarbons (including methylanthracene, pyrene, etc.) 49.2wt%; sulfur 0.635wt%, nitrogen 0.892wt%, a total metal element (Fe+Ni) content of 95ppm, and the rest are impurities (including colloids, asphaltene, etc.).

[0117] The total yield of the light component (fraction AD) is 58.5wt%; among the light components, the desulfurization rate of the light components is 95.5wt%, the denitrification rate is 95.7wt%, and the demetallization rate is 96.9wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0118] (3) The heavy fraction (E) with a temperature of >210°C is placed in a tube furnace, CO2 gas is used as an activator, the feed flow rate is 1.2 L / min, the carbonization temperature is 900°C, the carbonization time is 1 h, and the heating rate is 5°C / min to obtain activated carbon having the following characteristic parameters:

[0119] BET: 1405m 2 / g, total pore size: 0.45cm 3 / g, micropore: 0.43cm 3 / g, carbon yield: 68.9wt%.

[0120] (4) A light fraction (A) of ≤85°C and a fraction (D) of >117.5°C and ≤210°C are mixed, 0.7 wt% of a complexing agent Na / ZSM-5 is added thereto for reaction at a temperature of 58°C for 2.5 h, and then distilled at 80°C to obtain a diesel blending component, the weight percentage composition of which includes: 89.8% long-chain alkanes and cycloalkanes, no sulfur, no nitrogen, no metal elements (Fe+Ni), and the rest are aromatic hydrocarbons; the yield is 57.2% based on the total mass of fractions A and D.

[0121] (5) The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C is separated by rectification to obtain a naphthalene product with a purity of 96.7%. The yield calculated based on the mass of fraction B is 65.0%.

[0122] The methylnaphthalene-containing fraction (C) with a temperature of >101°C and ≤117.5°C is separated by rectification to obtain a methylnaphthalene product with a purity of 94.6%. The yield calculated based on the mass of fraction C is 67.3%.

[0123] Comparative Example 1

[0124] Referring to the method of Example 2, the only difference is that phosphoric acid is not added, and other operating conditions and parameters are the same. The proportion of each fraction based on the total mass of ethylene tar is shown in Table 5 below.

[0125] Table 5

[0126] A B C D E Proportion / wt% 1.46 21.9 9.1 0.2 67.34

[0127] Among them, the light fraction (A) ≤85°C has a weight percentage composition including: 39.3% straight-chain alkanes (including n-hexane, n-heptane, etc.), 34.2% cycloalkanes (including cyclohexane, methylcyclohexane, etc.), 26.2% aromatics (including toluene, xylene, etc.); and 0.025wt% sulfur, 0.057wt% nitrogen, and a total content of metal elements (Fe+Ni) of 5ppm.

[0128] The naphthalene-containing fraction (B) with a temperature of >85°C and ≤101°C comprises 55.9wt% naphthalene, 1.3wt% methylnaphthalene, 0.035wt% sulfur, 0.09wt% nitrogen, 8ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes and other aromatic hydrocarbons.

[0129] The methylnaphthalene fraction (C) with a temperature of >101°C and ≤117.5°C comprises 2.2wt% naphthalene, 78.9wt% methylnaphthalene, 0.120wt% sulfur, 0.11wt% nitrogen, 13ppm total metal element (Fe+Ni), and the remainder being alkanes, cycloalkanes and other aromatic hydrocarbons.

[0130] The fraction (D) with a temperature of >117.5°C and ≤210°C has a weight percentage composition of: 0.2wt% sulfur, 0.25wt% nitrogen, 19ppm total metal element (Fe+Ni), and the rest are alkanes, cycloalkanes, polycyclic aromatic hydrocarbons (including phenanthrene, anthracene, etc.).

[0131] The heavy fraction (E) at >210°C has a weight percentage composition of: 48.8wt% polycyclic aromatic hydrocarbons (including methylanthracene, pyrene, etc.); 0.28wt% sulfur, 0.425wt% nitrogen, 54ppm total metal element (Fe+Ni), and the rest are impurities (including colloids, asphaltene, etc.).

[0132] The total yield of the light component (fraction AD) is 45.1wt%; among the light components, the desulfurization rate of the light components is 42.1wt%, the denitrification rate is 45.6wt%, and the demetallization rate is 55.1wt%, calculated based on the S, N, and metal elements contained in the ethylene tar.

[0133] The heavy fraction (E) with a temperature of >210°C was placed in a tube furnace, CO2 gas was used as an activator, the feed flow rate was 0.8 L / min, the carbonization temperature was 900°C, the carbonization time was 1h, and the heating rate was 5°C / min to obtain activated carbon having the following characteristic parameters:

[0134] BET: 450m 2 / g, total pore size: 0.03cm 3 / g, micropore: 0.01cm 3 / g, carbon yield: 53.8wt%.

[0135] The diesel blending component is prepared from a light fraction (A) of ≤85°C and a fraction (D) of >117.5°C and ≤210°C, and its weight percentage composition includes: 84.5% long-chain alkanes and cycloalkanes, 42 ppm sulfur, 55 ppm nitrogen, 3 ppm metal elements (Fe+Ni), and the rest are aromatic hydrocarbons; based on the total mass of fractions A and D, the yield is 80.1%.

[0136] The naphthalene product separated from the naphthalene-containing fraction (B) with a temperature of more than 85° C. and less than or equal to 101° C. has a purity of 94.5%. The yield calculated based on the mass of fraction B is 54.5%.

[0137] The methylnaphthalene product separated from the methylnaphthalene-containing fraction (C) with a temperature of >101°C and ≤117.5°C has a purity of 94.1% and a yield of 56.2% based on the mass of fraction C.

[0138] It can be seen that compared with Examples 1-4 of the present invention, the desulfurization, denitrification and demetallization rates of the light component in Comparative Example 1 are significantly reduced, and the total sulfur and nitrogen metal content of the diesel blending component prepared from the light component is relatively high. At the same time, the yields of naphthalene and methylnaphthalene both decrease to varying degrees, and the charcoal yield obtained by carbonizing the heavy component and the basic properties of the activated carbon also decrease.

Claims

1. A method for resource utilization of ethylene tar, characterized in that: The steps include: (1) Ethylene tar is mixed with phosphoric acid and then heated to perform vacuum distillation; (2) Separating to obtain a light fraction of ≤85°C, a naphthalene-containing fraction of >85°C and ≤101°C, a methylnaphthalene-containing fraction of >101°C and ≤117.5°C, a fraction of >117.5°C and ≤210°C, and a heavy fraction of >210°C.

2. The method for resource utilization of ethylene tar according to claim 1, characterized in that: The ethylene tar in step (1) is a high-temperature condensation byproduct obtained by high-temperature cracking of hydrocarbon feedstocks during the production of ethylene; Preferably, based on the weight percentage of the ethylene tar being 100%, its element composition includes: C 85-95wt%, H 5-15wt%, sulfur ≤0.6wt%, nitrogen ≤1wt%, and metal elements ≤120ppm.

3. The method for resource utilization of ethylene tar according to claim 1, characterized in that: The amount of phosphoric acid added in step (1) is 10 to 40% of the mass of ethylene tar.

4. The method for resource utilization of ethylene tar according to claim 1, characterized in that: The vacuum distillation in step (1) is at a negative pressure of -0.5 to -0.05 MPa; Preferably, the reduced pressure distillation has a heating rate of 1 to 4°C / min.

5. The method for resource utilization of ethylene tar according to claim 1, characterized in that: Optionally, step (3) is included, which is to use CO2 gas as an activating agent to high-temperature carbonize the heavy fraction >210°C separated in step (2) to obtain activated carbon.

6. The method for resource utilization of ethylene tar according to claim 5, characterized in that: The high temperature carbonization operation has a carbonization temperature of 700 to 900° C. and a carbonization time of 1 to 4 hours; Preferably, the high temperature carbonization has a heating rate of 5 to 10°C / min; Preferably, the feed flow rate of the CO2 gas is 0.5 to 2 L / min.

7. The method for resource utilization of ethylene tar according to claim 1, characterized in that: Optionally, step (4) is included, which is to mix at least one of the light fraction ≤85°C and the fraction >117.5°C and ≤210°C separated in step (2) with a complexing agent for reaction, and then distill to obtain a diesel blending component.

8. The method for resource utilization of ethylene tar according to claim 7, characterized in that: The complexing agent is selected from at least one of molecular sieves, ethylenediaminetetraacetic acid, phosphate complexing agents, and thiol complexing agents, preferably at least one of modified ZSM-5 molecular sieves and thiol complexing agents, and more preferably Na / ZSM-5 molecular sieves; Preferably, the complexing agent is added in an amount of 0.01-2 wt%, calculated based on the total mass of the light fraction ≤85°C and the fraction >117.5°C and ≤210°C.

9. The method for resource utilization of ethylene tar according to claim 7, characterized in that: The complexation reaction is carried out at a temperature of 40 to 70°C and a time of 0.5 to 3 hours; The distillation temperature is 50-100°C.

10. The resource utilization method of ethylene tar according to claim 1, characterized in that: The naphthalene-containing fraction with a temperature of more than 85° C. and less than or equal to 101° C., and the methylnaphthalene-containing fraction with a temperature of more than 101° C. and less than or equal to 117.5° C., are respectively subjected to rectification treatment to obtain naphthalene and methylnaphthalene products.