Process for the production of high value chemical feedstocks from straight run diesel

Abstract

The present application relates to the technical field of diesel processing, and discloses a method for producing high-value chemical raw materials from straight-run diesel, comprising the following steps: (1) contacting straight-run diesel with a hydrocracking catalyst to perform a selective cracking reaction of alkyl cyclic hydrocarbon side chains, and obtaining a selective cracking product; wherein the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel is not less than 60%, and the total molar loss rate of naphthenes and aromatics in the selective cracking product is not higher than 15%; (2) separating the selective cracking product to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons; and (3) contacting the heavy fraction with a hydrogenation ring-opening catalyst to perform a hydrogenation ring-opening reaction. The method can obtain high-quality ethylene cracking raw materials and reforming raw materials with high aromatic potential content, and realizes efficient production of high-value chemical raw materials from straight-run diesel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of diesel oil processing, and particularly relates to a method for producing high-value chemical raw materials from straight-run diesel oil. BACKGROUND

[0002] In 2019, the domestic new oil refining capacity reached 25 million tons / year, and the total oil refining capacity reached 860 million tons / year, with a serious and persistent excess of oil refining capacity, while the terminal consumption of refined oil continued to slow down; among them, the apparent consumption of diesel oil in 2019 decreased by 6.25% year-on-year. Reducing the diesel-gasoline ratio and the outlet problem of refinery diesel oil has become one of the problems to be solved. In the diesel oil pool in China, the proportion of straight-run diesel oil reaches 50%, and the aromatic hydrocarbon mass fraction in straight-run diesel oil is generally higher than that in straight-run naphtha, which is not an ideal high-quality ethylene cracking raw material. If the straight-run diesel oil can be further processed to produce high-quality ethylene cracking raw materials with higher added value, on the one hand, it can reduce the diesel-gasoline ratio and solve the outlet problem of refinery diesel oil, and on the other hand, it can increase the diversity of raw materials for domestic ethylene cracking devices.

[0003] The straight-run diesel oil contains about 40% of paraffin hydrocarbons, and the cyclic hydrocarbons contain high-value alkyl side chains, and the proportion of chain carbon in the carbon distribution is more than 70%. If the units with paraffin hydrocarbon structure in this part can be converted into high-quality ethylene cracking raw materials, and the naked ring or less, short side chain cyclic hydrocarbons are obtained, and then the high-aromatic potential content naphtha is obtained through directional hydrogenation ring-opening reaction, the straight-run diesel oil can be efficiently and high-value converted into chemical raw materials. However, the control of the reaction process and the molecular structure of the product is the key and difficulty.

[0004] CN104611040A discloses a hydrocracking method, in which the heavy distillate oil is mixed with hydrogen, and then subjected to hydrofining and hydrocracking reactions in sequence, wherein the hydrocracking catalyst with reduced hydrogenation activity is loaded in the cracking reactor along the reaction flow direction, so as to improve the aromatic potential of heavy naphtha and selectivity.

[0005] CN102959054A discloses a combined hydrocracking and dewaxing method of hydrocarbons, in which the raw oil is sequentially subjected to hydroprocessing and first hydrocracking reaction to obtain a first hydrocracking reaction effluent, which is subjected to a first catalytic dewaxing reaction, and the reaction effluent is separated and fractionated to obtain a naphtha fraction, a first diesel oil fraction and a bottom product fraction, wherein the bottom product fraction is subjected to a second hydrocracking or second catalytic dewaxing reaction, and the reaction effluent is separated and fractionated to form a second diesel oil fraction and a lubricating oil product fraction.

[0006] The focus of the existing research is to control the conversion depth and the selectivity of the target distillate product, and there is still a lack of research on the selectivity of the conversion of different structural raw material molecules, the chain hydrocarbons and cyclic hydrocarbon structural units in the raw material molecules, and the molecular structure of the product. SUMMARY

[0007] The present application aims to overcome the problems of the prior art, such as the single product structure of fuel oil produced from straight-run diesel oil and the low utilization rate, and provides a method for producing high-value chemical raw materials from straight-run diesel oil, which can obtain high-quality ethylene cracking raw materials and heavy reforming raw materials with high aromatic potential content, and realizes efficient production of high-value chemical raw materials from straight-run diesel oil.

[0008] In order to achieve the above-mentioned purpose, the present application provides a method for producing high-value chemical raw materials from straight-run diesel oil, comprising the following steps:

[0009] (1) contacting straight-run diesel oil with a hydrocracking catalyst to perform a selective cracking reaction of alkyl cyclic hydrocarbon side chains, to obtain a selective cracking product; wherein the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 60%, and the total molar loss rate of naphthenes and aromatics in the cracking product is not higher than 15%;

[0010] (2) separating the selective cracking product to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons;

[0011] (3) contacting the heavy fraction with a hydrodearomatization catalyst to perform a hydrodearomatization reaction.

[0012] Compared with the prior art, the present application couples hydrocracking reaction and separation, maximally retains the original structure of the straight-run diesel oil raw material molecules, realizes the partition and directional conversion of the chain structure and the cyclic structure of petroleum hydrocarbons, and then contacts the heavy fraction with a hydrodearomatization catalyst to perform a hydrodearomatization reaction, which is beneficial to obtain naphtha with high aromatic potential content. Preferably, the light fraction obtained after the hydrocracking reaction and separation has a high proportion of n-alkanes, which can be used as high-quality ethylene cracking raw materials. The above-mentioned method can realize the high-value utilization of straight-run diesel oil. DETAILED DESCRIPTION

[0013] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and any values are understood to be approximate values. The exact numerical values of the endpoints of the ranges and the separate points are not to be understood as being strictly limited to the exact numerical values recited. At the very least, each minimum numerical limitation should at least be construed in the context as permitting some slack between the minimum and maximum values to allow for experimentation and / or variation.

[0014] The present application provides a method for producing high-value chemical raw materials from straight-run diesel oil, comprising the following steps:

[0015] (1) contacting straight-run diesel oil with a hydrocracking catalyst to perform a selective cracking reaction of alkyl cyclic hydrocarbon side chains, to obtain a selective cracking product; wherein the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 60%, and the total molar loss rate of naphthenes and aromatics in the selective cracking product is not higher than 15%;

[0016] (2) separating the selective cracking product to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons;

[0017] (3) contacting the heavy fraction with a hydrodearomatization catalyst to perform a hydrodearomatization reaction.

[0018] According to the present application, the hydrocracking reaction in step (1) mainly occurs including cracking of chain hydrocarbons, breaking of alkyl side chains of cyclic hydrocarbons and dealkylation reaction, after the hydrocracking reaction, the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 60%, and the total molar loss rate of naphthenes and aromatics in the selective cracking product is not higher than 15% compared with the straight-run diesel oil, in this case, the original structure of the straight-run diesel oil raw material molecules can be retained in the maximum amount, and the partition and directional conversion of the chain structure and the cyclic structure of petroleum hydrocarbons are realized, which is beneficial to obtain a reforming raw material with high aromatic potential content.

[0019] The present application does not have special limitations on the composition and source of the straight-run diesel oil, and the straight-run diesel oil of the present application can be applied to the present application. Preferably, the straight-run diesel oil comprises chain hydrocarbons, substituted or unsubstituted naphthenes and substituted or unsubstituted aromatics, the content of the chain hydrocarbons is 20-70wt%, preferably 30-60wt% based on the total mass of the straight-run diesel oil; the content of the substituted or unsubstituted naphthenes is 10-50wt%, preferably 20-40wt%; and the content of the substituted or unsubstituted aromatics is 5-40wt%, preferably 10-30wt%. The substituent group in the substituted naphthene or aromatic hydrocarbon can be, for example, C3-C6 alkane.

[0020] In the present application, the "alkyl cyclic hydrocarbon" refers to alkyl-substituted aromatic hydrocarbon and alkyl-substituted naphthene.

[0021] According to some preferred embodiments of the present application, the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 70%, preferably 70-90%. Controlling the side chain breaking rate of alkyl cyclic hydrocarbons in the raw material within the above preferred range is beneficial to retain the original structure of the straight-run diesel oil raw material molecules, and realize the partition and directional conversion of the chain structure and the cyclic structure of petroleum hydrocarbons.

[0022] According to some preferred embodiments of the present application, the total molar loss rate of naphthenes and aromatics in the cracking product is not higher than 12%, preferably 4-12%, compared with the straight-run diesel.

[0023] In the present application, the total molar loss rate (%) of naphthenes and aromatics = the molar amount of naphthenes and aromatics in the cracking product / the molar amount of naphthenes and aromatics in the straight-run diesel x 100%. The molar amount of naphthenes and aromatics in the cracking product and the molar amount of naphthenes and aromatics in the straight-run diesel are determined and calculated by the coal diesel hydrocarbon composition (SH0606) and hydrocarbon carbon number distribution (HCND) methods.

[0024] The present application has a wide range of selection for the hydrocracking catalyst used in the selective cracking reaction. Any catalyst known in the art capable of catalyzing the hydrocracking reaction can be used to meet the above-mentioned side chain breaking rate of alkyl cyclic hydrocarbons and the molar loss rate of cyclic hydrocarbons and aromatics.

[0025] According to some preferred embodiments of the present application, the hydrocracking catalyst comprises a first molecular sieve and a first active metal component, the first molecular sieve is selected from a molecular sieve with ten-membered ring channels or a molecular sieve with both ten-membered ring and twelve-membered ring channels, preferably at least one of MFI, EUO and NES molecular sieves. The use of the above-mentioned preferred first molecular sieve is beneficial to the selective cracking of alkyl cyclic hydrocarbons and helps to maximize the retention of the original structure of the straight-run diesel feed molecules.

[0026] According to the present application, preferably, the first active metal component is selected from at least one of Group VIII metals and Group VIB metals, the Group VIII metal is preferably at least one of Fe, Co, Ni, Ru, Rh, Pd, Pt, more preferably Ni and / or Co. The Group VIB metal is preferably at least one of Mo, Cr, W, more preferably Mo.

[0027] In the present application, the first active metal component can only contain Group VIII metals, only contain Group VIB metals, or contain both Group VIII metals and Group VIB metals.

[0028] According to some preferred embodiments of the present application, the first active metal component comprises at least one of Group VIII metal elements and at least one of Group VIB metal elements. Preferably, the first active metal component comprises Ni and / or Co, and Mo. In the above-mentioned preferred case, it is beneficial to further improve the catalytic activity of the hydrocracking catalyst.

[0029] The content of each component in the hydrocracking catalyst is selected from a wide range, preferably, the content of the first molecular sieve is 0.5-50wt%, preferably 3-30wt% based on the total mass of the hydrocracking catalyst; the content of the Group VIII metal is 1-10wt%, preferably 1-6wt% based on the metal oxide; and the content of the Group VIB metal is 1-40wt%, preferably 5-35wt%.

[0030] In the present application, the hydrocracking catalyst can further contain a first heat-resistant inorganic oxide matrix, and the content of the first heat-resistant inorganic oxide matrix is not particularly limited, and is subject to the content of the first molecular sieve and the first active metal component as described above, and the rest is the first heat-resistant inorganic oxide according to the principle of 100%.

[0031] The specific type of the first heat-resistant inorganic oxide is not particularly limited in the present application, and a conventional heat-resistant inorganic oxide in the art can be used. Preferably, the first heat-resistant inorganic oxide matrix is alumina and / or silica, for example, it can be alumina, silica or alumina-silica composite oxide. The first heat-resistant inorganic oxide matrix can be a commercially available product or prepared by any known preparation method, and the present application is not particularly limited in this regard.

[0032] The selection range of the alumina is wide, and any one of γ, η, θ, δ and χ transition phase alumina can be selected, and γ-alumina is preferred. The alumina can further contain an auxiliary element, and the auxiliary element is preferably any one of silicon, titanium, magnesium, boron, zirconium, thorium, niobium, cerium, lanthanum and praseodymium. Preferably, the content of the auxiliary element is 0.1-5wt% based on the total amount of the alumina.

[0033] Preferably, the silica-alumina composite oxide has a pseudo-boehmite structure, and can be a commercially available product or prepared by any prior art. For example, the Siral series of commercially available silica-alumina produced by Condea Company in Germany.

[0034] The specific conditions of the hydrocracking reaction are not particularly limited in the present application, and are also subject to the scission rate of the alkyl cyclic hydrocarbon and the molar loss rate of the cyclic hydrocarbon and aromatic hydrocarbon as described above.

[0035] According to some preferred embodiments of the present application, the conditions of the hydrocracking reaction include: hydrogen partial pressure is 3-20MPa, preferably 3-10MPa; reaction temperature is 280-400℃, preferably 280-370℃; liquid hourly space velocity is 1-6h -1 , preferably 1.5-4h -1, the hydrogen to oil volume ratio is 300-1500, preferably 300-1000. In the present application, the pressure referred to is gauge pressure unless otherwise specified.

[0036] In the present application, the selective cracking product is separated into a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons by the separation of step (2). The present application does not have a particular limitation on the mode and conditions of the separation, as long as the chain hydrocarbons and the cyclic hydrocarbons can be separated, and the person skilled in the art can select as appropriate.

[0037] According to some preferred embodiments of the present application, the separation mode is fractional distillation, and preferably, the fractional distillation temperature is 175-220°C.

[0038] According to the present application, the heavy fraction rich in cyclic hydrocarbons obtained by the separation is contacted with a hydrogenation ring-opening catalyst to perform a hydrogenation ring-opening reaction, and the light fraction rich in chain hydrocarbons obtained can be used as an ethylene cracking raw material after optional fractional distillation.

[0039] According to the present application, the hydrogenation ring-opening reaction of step (3) is performed so that the ring-opening rate of the polycyclic cyclic hydrocarbons in the heavy fraction is greater than 60%, and preferably 80-95%. The "polycyclic cyclic hydrocarbons" include aromatic hydrocarbons and naphthenes containing two or more rings. Controlling the ring-opening rate of the polycyclic cyclic hydrocarbons in the heavy fraction within the above-mentioned preferred range is advantageous for maximizing the conversion of straight-run diesel into chemical raw materials and improving the aromatic potential of the heavy naphtha product.

[0040] The ring-opening rate of the polycyclic cyclic hydrocarbons in the heavy fraction is calculated according to the following formula,

[0041] Ring-opening rate (%) = (N1 - n1) / N1 x 100%;

[0042] wherein N1 represents the sum of the amounts of substance of the polycyclic cyclic hydrocarbons such as aromatic hydrocarbons and naphthenes containing two or more rings in the heavy fraction, and n1 represents the sum of the amounts of substance of the polycyclic cyclic hydrocarbons such as aromatic hydrocarbons and naphthenes containing two or more rings in the hydrogenation ring-opening product, and the units are both mol. The amounts of substance are obtained from the test results of the hydrocarbon composition and the carbon number distribution of the hydrocarbons.

[0043] The present application has a wide selection range for the hydrocracking catalyst used in the hydrogenation ring-opening reaction, and a catalyst known in the art that can catalyze the hydrocracking reaction can be used to meet the above-mentioned ring-opening rate of the aromatic hydrocarbons and naphthenes containing two or more rings in the heavy fraction.

[0044] According to some preferred embodiments of the present application, the hydrogenation ring-opening catalyst comprises a second molecular sieve and a second active metal component, and the second molecular sieve is a molecular sieve with twelve-membered ring pores, and preferably a FAU and / or BEA molecular sieve.

[0045] Preferably, the second molecular sieve has a molar ratio of silica to alumina of 3 to 50, preferably 3 to 30.

[0046] Preferably, the second active metal component is selected from at least one of Group VIII metal elements and Group VIB metal elements; the Group VIII metal is preferably at least one of Fe, Co, Ni, Ru, Rh, Pd, Pt, and more preferably Ni and / or Co. The Group VIB metal is preferably at least one of Mo, Cr, W, and more preferably Mo.

[0047] In the present application, the second active metal component can contain only Group VIII metal, only Group VIB metal, or both Group VIII metal and Group VIB metal.

[0048] According to some preferred embodiments of the present application, the second active metal component comprises at least one of Group VIII metal elements and at least one of Group VIB metal elements. In the above preferred case, it is beneficial to further improve the catalytic activity of the hydrodearomatization catalyst.

[0049] According to some particularly preferred embodiments of the present application, the second active metal component comprises Ni and / or Co, and Mo.

[0050] According to some preferred embodiments of the present application, the content of the second molecular sieve is 10 to 80 wt%, preferably 30 to 75 wt%, based on the total mass of the hydrodearomatization catalyst; the content of Group VIII metal is 0.5 to 6 wt%, preferably 0.5 to 4 wt%, based on the metal oxide; and the content of Group VIB metal is 1 to 30 wt%, preferably 2 to 25 wt%.

[0051] Preferably, the hydrodearomatization catalyst further comprises a second heat-resistant inorganic oxide matrix, which is selected from the same range as defined for the first heat-resistant inorganic oxide matrix, and will not be repeated here.

[0052] In the present application, "first" and "second" in "first molecular sieve", "second molecular sieve", "first active metal component", "second active metal component", "first heat-resistant inorganic oxide matrix", and "second heat-resistant inorganic oxide matrix" are only used to distinguish different components in the hydrocracking catalyst and the hydrodearomatization catalyst.

[0053] The present application does not have a particular limitation on the source of the hydrocracking catalyst and the hydrodearomatization catalyst, which can be commercially available or prepared by any known preparation method in the art.

[0054] According to some preferred embodiments of the present application, the temperature of the hydrocracking reaction is not higher than the temperature of the hydrodearomatization reaction, preferably, the temperature of the hydrocracking reaction is 10-50℃ lower than the temperature of the hydrodearomatization reaction. By using the above preferred embodiments, the maximum retention of the original structure of the chain hydrocarbons in the hydrocracking reaction zone is facilitated, coking is inhibited, and the ring-opening activity of the hydrodearomatization reaction is enhanced.

[0055] According to some preferred embodiments of the present application, the conditions of the hydrodearomatization reaction include: hydrogen partial pressure of 3-20 MPa, preferably 3-10 MPa, reaction temperature of 320-450℃, preferably 350-430℃; liquid hourly space velocity of 0.5-5 h -1 , preferably 0.5-3 h -1 , hydrogen to oil volume ratio of 300-1500, preferably 600-1500.

[0056] The method for producing high-value chemical raw materials from straight-run diesel oil provided by the present application can be carried out in any reaction device sufficient for the straight-run diesel oil to be contacted with the catalyst under the hydroprocessing reaction conditions, for example, the hydrocracking reaction and the hydrodearomatization reaction can be carried out in a fixed bed reactor, a moving bed reactor or a boiling bed reactor.

[0057] In the present application, the light fraction separated after the hydrocracking reaction has a relatively high proportion of normal hydrocarbons, which can be directly used as a high-quality ethylene cracking raw material, or the light fraction can be mixed with the product obtained by the hydrodearomatization reaction to carry out a second separation to obtain light naphtha and heavy naphtha.

[0058] According to some preferred embodiments of the present application, the method further comprises: mixing the product of the hydrodearomatization reaction with the light fraction rich in chain hydrocarbons to carry out a second separation to obtain light naphtha and heavy naphtha.

[0059] The second separation can be carried out in a conventional manner and under conventional conditions in the art, preferably, the second separation is fractional distillation, and the cutting temperature of the second separation is 160-180℃.

[0060] The present application will be described in detail below by way of examples.

[0061] In the following examples, the density of the straight-run diesel oil used is 0.8177 g / cm 3 , wherein the paraffin content is 59.3 wt%, the naphthene content is 29 wt%, and the aromatic content is 11.7 wt%.

[0062] Example 1

[0063] The hydrocracking reaction zone is packed with a hydrocracking catalyst containing EUO type molecular sieve, which is from Sinopec Catalyst Co., Ltd. Changling Branch. The hydrocracking catalyst comprises 15 wt% EUO type molecular sieve, 3.2 wt% NiO, 20 wt% MoO3 and 61.8 wt% γ-alumina, wherein the molar ratio of silicon oxide and aluminum oxide in the EUO type molecular sieve is 30.

[0064] The hydrodearomatization reaction zone is packed with a hydrodearomatization catalyst containing BEA type molecular sieve, which is from Sinopec Catalyst Co., Ltd. Changling Branch. The hydrodearomatization catalyst comprises 50 wt% BEA type molecular sieve, 1.6 wt% NiO, 15 wt% MoO3 and 33.4 wt% γ-alumina, wherein the molar ratio of silicon oxide and aluminum oxide in the BEA type molecular sieve is 25.

[0065] (1) The straight-run diesel is sent into the hydrocracking reaction zone to contact with the hydrocracking catalyst to perform hydrocracking reaction, and the reaction conditions include 6.4 MPa, 340°C, 2.0 h -1 , hydrogen to oil ratio 700. The side chain breaking rate of alkyl cyclic hydrocarbons with side chain carbon number greater than 2 in the cracking product is 66.5% compared with the straight-run diesel, and the total molar loss rate of naphthenes and aromatics is 12.7%.

[0066] (2) The obtained cracking product is subjected to fractionation, and the cutting temperature is 200°C to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons, wherein the yield of the light fraction is 25.2%.

[0067] (3) The heavy fraction is sent into the hydrodearomatization reaction zone to contact with the hydrodearomatization catalyst to perform hydrodearomatization reaction, and the reaction conditions include 6.4 MPa, 390°C, 1.0 h -1 , hydrogen to oil ratio 1100, to obtain a hydrodearomatization product. The ring opening rate of polycyclic cyclic hydrocarbons in the heavy fraction is calculated according to the following formula, and the results are shown in Table 1,

[0068] Ring opening rate (%) = (N1-n1) / N1x100%;

[0069] wherein N1 represents the sum of the amounts of substances of polycyclic cyclic hydrocarbons such as aromatics, naphthenes and the like with two or more rings in the heavy fraction, and n1 represents the sum of the amounts of substances of polycyclic cyclic hydrocarbons such as aromatics, naphthenes and the like with two or more rings in the hydrodearomatization product, and the units are both mol. The amount of substance is obtained by calculation from the test results of hydrocarbon composition and hydrocarbon carbon number distribution.

[0070] (4) The light fraction and the hydrogenation ring-opening product of the heavy fraction are fed into a fractionating column, and a cutting temperature is 165°C, to obtain light naphtha rich in linear hydrocarbons and heavy naphtha rich in cyclic hydrocarbons, which are used as ethylene cracking raw material and aromatic hydrocarbon raw material respectively, and product compositions are shown in Table 1.

[0071] In Table 1, the ratio of normal alkanes to isomeric alkanes in the light naphtha is calculated by the following formula,

[0072]

[0073] In Table 1, the ratio of normal alkanes to isomeric alkanes in the light naphtha is calculated by the following formula,

[0074] In Table 1, the aromatic content (wt%) in the heavy naphtha is calculated by the following formula,

[0075] The aromatic content (wt%) in the heavy naphtha = a x C6N + b x C7N + c x C8N + d x C9N + e x C10N + Σ all aromatics;

[0076] In Table 1, the ratio of normal alkanes to isomeric alkanes in the light naphtha is calculated by the following formula,

[0077] Example 2

[0078] The hydrogenation cracking reaction zone is filled with a hydrogenation cracking catalyst containing MFI type molecular sieve, which is from Changling Branch Company of Sinopec Catalyst Co., Ltd. The hydrogenation cracking catalyst includes 15wt% MFI type molecular sieve, 3.2wt% NiO, 20wt% MoO3, and 61.8wt% γ-alumina, wherein the molar ratio of silicon oxide and alumina of the MFI type molecular sieve is 36.

[0079] The hydrogenation ring-opening reaction zone is filled with a hydrogenation ring-opening catalyst containing FAU type molecular sieve, which is from Changling Branch Company of Sinopec Catalyst Co., Ltd. The hydrogenation ring-opening catalyst includes 50wt% FAU type molecular sieve, 1.6wt% NiO, 15wt% MoO3, and 33.4wt% γ-alumina, wherein the molar ratio of silicon oxide and alumina of the FAU type molecular sieve is 6.

[0080] (1) The straight-run diesel oil is sent into a hydrocracking reaction zone to contact with a hydrocracking catalyst to perform a hydrocracking reaction, and the reaction conditions include 6.4 MPa, 340 ℃, 2.0 h -1 , and a hydrogen to oil ratio of 700. The side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the cracking product is 72.6%, and the total molar loss rate of naphthenes and aromatics is 10.4%.

[0081] (2) The obtained cracking product is subjected to fractionation to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons, and the yield of the light fraction is 28.4% at a cutting temperature of 200 ℃.

[0082] (3) The heavy fraction is sent into a hydrodearomatization reaction zone to contact with a hydrodearomatization catalyst to perform a hydrodearomatization reaction, and the reaction conditions include 6.4 MPa, 390 ℃, 1.0 h -1 , a hydrogen to oil ratio of 1100, and a hydrodearomatization product is obtained. The ring opening rate of aromatics and naphthenes with two or more rings in the heavy fraction is shown in Table 1.

[0083] (4) The light fraction in step (2) and the hydrodearomatization product are sent into a fractionating column together to obtain a light naphtha rich in chain hydrocarbons and a heavy naphtha rich in cyclic hydrocarbons at a cutting temperature of 165 ℃, and the product composition is shown in Table 1.

[0084] Example 3

[0085] The hydrocracking reaction zone is filled with a hydrocracking catalyst containing EUO type molecular sieve, and the EUO type molecular sieve is from Changling Branch of Sinopec Catalyst Co., Ltd. The hydrocracking catalyst includes 30 wt% EUO type molecular sieve, 3.2 wt% NiO, 20% MoO3, and 46.8 wt% γ-alumina, and the molar ratio of silicon oxide and aluminum oxide of the EUO type molecular sieve is 36.

[0086] The hydrodearomatization reaction zone is filled with a hydrodearomatization catalyst containing FAU type molecular sieve, and the FAU type molecular sieve is from Changling Branch of Sinopec Catalyst Co., Ltd. The hydrodearomatization catalyst includes 50 wt% FAU type molecular sieve, 1.6 wt% NiO, 15% MoO3, and 33.4 wt% γ-alumina, and the molar ratio of silicon oxide and aluminum oxide of the FAU type molecular sieve is 6.

[0087] (1) The straight-run diesel oil is sent into a hydrocracking reaction zone to contact with a hydrocracking catalyst to perform a hydrocracking reaction, and the reaction conditions include 6.4 MPa, 340 ℃, 2.0 h -1 , and a hydrogen to oil ratio of 700. The side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the cracking product is 72.6%, and the total molar loss rate of naphthenes and aromatics is 10.4%.

[0088] (2) The obtained cracking product is subjected to fractionation at a cutting temperature of 200°C to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons, wherein the yield of the light fraction is 35.7%.

[0089] (3) The heavy fraction enters a hydrogenation ring-opening reaction zone and is subjected to hydrogenation ring-opening reaction with a hydrogenation ring-opening catalyst, the reaction conditions including 6.4 MPa, 390°C, 1.0 h -1 , hydrogen to oil ratio 1100, to obtain a hydrogenation ring-opening product. The ring-opening rate of aromatic hydrocarbons and naphthenes with two or more rings in the heavy fraction is shown in Table 1.

[0090] (4) The light fraction in step (2) and the above hydrogenation ring-opening product enter a fractionation column together, and the cutting temperature is 165°C to obtain light naphtha rich in chain hydrocarbons and heavy naphtha rich in cyclic hydrocarbons, and the product composition is shown in Table 1.

[0091] Example 4

[0092] The hydrogenation cracking reaction zone is filled with a hydrogenation cracking catalyst containing MFI type molecular sieve, which is from Changling Branch of Sinopec Catalyst Co., Ltd. The hydrogenation cracking catalyst includes 15wt% MFI type molecular sieve, 3.2wt% NiO, 20wt% MoO3 and 61.8wt% γ-alumina, wherein the molar ratio of silicon oxide and aluminum oxide of the MFI type molecular sieve is 30.

[0093] The hydrogenation ring-opening reaction zone is filled with a hydrogenation ring-opening catalyst containing BEA type molecular sieve, which is from Changling Branch of Sinopec Catalyst Co., Ltd. The hydrogenation ring-opening catalyst includes 50wt% BEA type molecular sieve, 1.6wt% NiO, 15wt% MoO3 and 33.4wt% γ-alumina, wherein the molar ratio of silicon oxide and aluminum oxide of the BEA type molecular sieve is 25.

[0094] (1) Straight-run diesel is sent into a hydrogenation cracking reaction zone and is subjected to hydrogenation cracking reaction with a hydrogenation cracking catalyst, the reaction conditions including 6.4 MPa, 350°C, 2.0 h -1 , hydrogen to oil ratio 700. The side chain breaking rate of alkyl cyclic hydrocarbons with side chain carbon number greater than 2 in the hydrogenation cracking product is 75.2%, and the total molar loss rate of naphthenes and aromatic hydrocarbons is 8.8%.

[0095] (2) The obtained cracking product is subjected to fractionation at a cutting temperature of 200°C to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons, wherein the yield of the light fraction is 27.6%.

[0096] (3) The heavy fraction enters a hydrogenation ring-opening reaction zone and is subjected to hydrogenation ring-opening reaction with a hydrogenation ring-opening catalyst, the reaction conditions including 6.4 MPa, 400°C, 1.0 h -1, hydrogen to oil ratio 1100, to obtain the hydrogenation ring-opening product. The ring-opening rate of the aromatic hydrocarbons and naphthenes with two or more rings in the heavy fraction is shown in Table 1.

[0097] (4) The light fraction in step (2) and the above hydrogenation ring-opening product are fed into a fractionating column, and a cutting temperature is 165°C, to obtain light naphtha rich in chain hydrocarbons and heavy naphtha rich in cyclic hydrocarbons, and the product composition is shown in Table 1.

[0098] Comparative Example 1

[0099] A single reactor and a single catalyst are used for the reaction, and straight-run diesel is directly contacted with a hydrogenation ring-opening catalyst to perform ring-opening reaction. The catalyst is a hydrogenation ring-opening catalyst containing FAU type molecular sieve, and the FAU type molecular sieve is from Sinopec Catalyst Co., Ltd. Changling Branch, and the molar ratio of silicon oxide to alumina is 6. The hydrogenation ring-opening catalyst comprises 50wt% FAU type molecular sieve, 1.6wt% NiO, 15wt% MoO3, and 33.4wt% γ-alumina. The reaction conditions include 6.4MPa, 370°C, 1.5h -1 , hydrogen to oil ratio 1000. The full fraction analysis result shows that the side chain breaking rate of alkyl cyclic hydrocarbons with side chain carbon number greater than 2 is 58.7% relative to the straight-run diesel raw material, and the ring-opening rate of polycyclic cyclic hydrocarbons is 25.6%.

[0100] The above reaction product is fed into a fractionating column, and a cutting temperature is 165°C, to obtain light naphtha fraction and heavy naphtha fraction, and the product composition is shown in Table 1.

[0101] Comparative Example 2

[0102] The hydrogenation cracking catalyst 1 and the hydrogenation cracking catalyst 2 are sequentially filled in the reactor, wherein,

[0103] The hydrogenation cracking catalyst 1 comprises 50wt% BEA type molecular sieve (purchased from Sinopec Catalyst Co., Ltd. Changling Branch), 1.6wt% NiO, 15wt% MoO3, and 33.4wt% γ-alumina, and the molar ratio of silicon oxide to alumina of the BEA type molecular sieve is 25.

[0104] The hydrogenation cracking catalyst 2 comprises 15wt% MFI type molecular sieve (purchased from Sinopec Catalyst Co., Ltd. Changling Branch), 3.2wt% NiO, 20wt% MoO3, and 61.8wt% γ-alumina, and the molar ratio of silicon oxide to alumina of the MFI type molecular sieve is 30.

[0105] The straight-run diesel is first contacted with the hydrogenation cracking catalyst 1 to perform reaction, and the reaction conditions include 6.4MPa, 370°C, 1.5h -1The hydrogen to oil ratio is 1100. Compared with the straight-run diesel, the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the cracking product is 43.2%, and the total molar loss rate of naphthenes and aromatics is 38.8%.

[0106] The obtained product is then contacted with the hydrocracking catalyst 2 for reaction under the reaction conditions of 6.4 MPa, 370 DEG C, 1.5 h -1 , and a hydrogen to oil ratio of 1100.

[0107] The above reaction product is sent into a fractionating column, and a cutting temperature is 165 DEG C, so as to obtain a light naphtha fraction and a heavy naphtha fraction, and the product composition is shown in Table 1. The full fraction analysis result shows that, compared with the straight-run diesel raw material, the ring opening rate of polycyclic cyclic hydrocarbons is 60.8%.

[0108] Table 1

[0109]

[0110] It can be seen from the comparison of the above examples and the comparative examples that the method for producing high-value chemical raw materials from straight-run diesel provided by the present application can maximize the preservation of the original structure of the straight-run diesel raw material molecules, the obtained heavy naphtha has a high aromatic potential content, and the light naphtha has a high n-alkane / isomerized alkane ratio, which is beneficial to being used as a high-quality ethylene cracking raw material, so that the high-value utilization of straight-run diesel can be realized.

[0111] The above describes the preferred embodiments of the present application in detail, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as the disclosed content of the present application, and all fall within the protection scope of the present application.

Claims

1. A process for the production of high value chemical feedstocks from straight run diesel, characterized by, The method comprises the following steps: (1) contacting straight-run diesel oil with a hydrocracking catalyst to perform a selective cracking reaction of alkyl cyclic hydrocarbon side chains, to obtain a selective cracking product; wherein the side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 60%, and the total molar loss rate of naphthenes and aromatics in the selective cracking product is not higher than 15%; The hydrocracking catalyst comprises a first molecular sieve and a first active metal component, and the first molecular sieve is selected from a molecular sieve with ten-membered ring pores or a molecular sieve with both ten-membered ring pores and twelve-membered ring pores; (2) separating the selective cracking product to obtain a light fraction rich in chain hydrocarbons and a heavy fraction rich in cyclic hydrocarbons; (3) contacting the heavy fraction with a hydroisomerization catalyst to perform a hydroisomerization reaction; The hydroisomerization catalyst comprises a second molecular sieve and a second active metal component, and the second molecular sieve is a molecular sieve with twelve-membered ring pores.

2. The method of claim 1, wherein, The total molar loss rate of naphthenes and aromatics in the selective cracking product is not higher than 12%.

3. The method of claim 2, wherein, The total molar loss rate of naphthenes and aromatics in the selective cracking product is 4-12%.

4. The method of claim 1, wherein, The side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is not less than 70%.

5. The method of claim 4, wherein, The side chain breaking rate of alkyl cyclic hydrocarbons with a side chain carbon number greater than 2 in the straight-run diesel oil is 70-90%.

6. The method of claim 1, wherein, The hydroisomerization reaction in step (3) causes the ring-opening rate of polycyclic cyclic hydrocarbons in the heavy fraction to be not less than 60%.

7. The method of claim 6, wherein, The hydroisomerization reaction in step (3) causes the ring-opening rate of polycyclic cyclic hydrocarbons in the heavy fraction to be 80-95%.

8. The method of claim 1, wherein, The first molecular sieve is selected from at least one of MFI, EUO and NES molecular sieves.

9. The method of claim 1, wherein, The first active metal component is selected from at least one of a Group VIII metal and a Group VIB metal.

10. The method of claim 9, wherein, The Group VIII metal is at least one of Fe, Co, Ni, Ru, Rh, Pd and Pt.

11. The method of claim 9, wherein, The Group VIB metal is at least one of Mo, Cr and W.

12. The method of claim 9, wherein, The content of the first molecular sieve is 0.5-50 wt% based on the total mass of the hydrocracking catalyst; the content of the Group VIII metal is 1-10 wt% and the content of the Group VIB metal is 1-40 wt% based on metal oxides.

13. The method of claim 12, wherein, The content of the first molecular sieve is 3-30 wt% based on the total mass of the hydrocracking catalyst; the content of the Group VIII metal is 1-6 wt% and the content of the Group VIB metal is 5-35 wt% based on metal oxides.

14. The method of claim 1, wherein, The hydrocracking catalyst further comprises a first heat-resistant inorganic oxide matrix.

15. The method of claim 14, wherein, The first heat-resistant inorganic oxide matrix is alumina and / or silica.

16. The method of claim 1, wherein, The second molecular sieve is a FAU and / or BEA molecular sieve.

17. The method of claim 16, wherein, The molar ratio of silica to alumina of the second molecular sieve is 3-50.

18. The method of claim 1, wherein, The second active metal component is selected from at least one of a Group VIII metal element and a Group VIB metal element.

19. The method of claim 18, wherein, The content of the second molecular sieve is 10-80 wt% based on the total mass of the hydrogenation ring-opening catalyst; the content of Group VIII metal is 0.5-6 wt% based on metal oxides, and the content of Group VIB metal is 1-30 wt%.

20. The method of claim 19, wherein, The content of the second molecular sieve is 30-75 wt% based on the total mass of the hydrogenation ring-opening catalyst; the content of Group VIII metal is 0.5-4 wt% based on metal oxides, and the content of Group VIB metal is 2-25 wt%.

21. The method of claim 1, wherein, The hydrogenation ring-opening catalyst further comprises a second heat-resistant inorganic oxide matrix.

22. The method of claim 21, wherein, The second heat-resistant inorganic oxide matrix is alumina and / or silica.

23. The method of any one of claims 1-22, wherein, The temperature of the hydrogenation cracking reaction is not higher than the temperature of the hydrogenation ring-opening reaction.

24. The method of claim 23, wherein, The temperature of the hydrogenation cracking reaction is 10-60℃ lower than the temperature of the hydrogenation ring-opening reaction.

25. The method of claim 23, the conditions of the hydrocracking reaction comprising: The hydrogen partial pressure is 3-20 MPa, the reaction temperature is 280-400℃, the liquid hourly space velocity is 1-6h -1 , and the hydrogen to oil volume ratio is 300-1500.

26. The method of claim 25, the conditions of the hydrocracking reaction comprising: The hydrogen partial pressure is 3-10 MPa, the reaction temperature is 280-370℃, the liquid hourly space velocity is 1.5-4 h -1 , and the hydrogen to oil volume ratio is 300-1000.

27. The method of any one of claims 1-22, wherein, The conditions of the hydrogenation ring-opening reaction include: hydrogen partial pressure of 3-20 MPa, reaction temperature of 320-450℃; liquid hourly space velocity of 0.5-5h -1 , hydrogen to oil volume ratio of 300-1500.

28. The method of claim 27, wherein, The conditions of the hydrogenation ring-opening reaction include: hydrogen partial pressure of 3-10 MPa, reaction temperature of 350-430℃; liquid hourly space velocity of 0.5-3h -1 , hydrogen to oil volume ratio of 600-1500.

29. The method of any one of claims 1-22, wherein, The separation is by fractionation.

30. The method of claim 29, wherein, The cutting temperature is 165-220℃.

31. The method of any one of claims 1-22, wherein, The method further comprises mixing the product of the hydrogenation ring-opening reaction with a light fraction rich in chain hydrocarbons to perform a second separation to obtain light naphtha and heavy naphtha.

32. The method of claim 31, wherein, The cutting temperature of the second separation is 160-180℃.

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