A process for the processing of sulfur-containing naphthas

Abstract

The application discloses a processing method of sulfur-containing naphtha. The method comprises the following steps: (1) mixing the sulfur-containing naphtha with hydrogen, and passing the mixture through a hydroconversion reaction zone, wherein the hydroconversion reaction zone is filled with at least two hydroconversion catalyst beds, and the mass content of active metals in the downstream catalyst bed is 1-25 percentage points lower than that in the upstream catalyst bed in terms of oxides; (2) carrying out high-pressure separation on the hydroconversion reaction effluent obtained in the step (1), and separating hydrogen-rich gas and liquid phase effluent, wherein the liquid phase effluent enters a separation system, and ethane, propane and n-butane are separated. The method can solve the problem of sulfur injection in an ethylene production device by using hydrogen sulfide-containing hydrogenation products as ethylene raw materials.

Description

Technical Field

[0001] This invention belongs to the field of hydrocarbon oil hydroconversion, specifically relating to a hydroconversion method for producing high-quality ethylene feedstock from sulfur-containing naphtha. Background Technology

[0002] With the need for upgrading and transforming oil refining towards chemical production, the use of hydrocracking light naphtha as a gasoline blending component is gradually decreasing, while its use as a feedstock for ethylene is gradually increasing. Hydrocracking reactions follow a carbocation reaction mechanism. Hydrocracking light naphtha has a high content of isoalkanes, which, when used as a feedstock for ethylene, will reduce the yield of ethylene and trienes in ethylene plants. Since feedstock costs account for more than 60% of the total cost of ethylene plants, using hydrocracking light naphtha as a feedstock for ethylene will significantly reduce the economic efficiency of ethylene plants.

[0003] CN115612524A discloses a method for increasing the concentration of n-chain alkanes in a light naphtha feed stream. The method includes separating the naphtha feed stream into a stream rich in n-chain alkanes and a stream rich in non-n-chain alkanes. An isomerization feed stream is obtained from the non-n-chain alkanes stream and isomerized on an isomerization catalyst to convert the non-n-chain alkanes into n-chain alkanes and generate an isomerized effluent. Optionally, the isomerized effluent can be separated into a propane stream and a C4 stream in a single column. + Hydrocarbon feedstock. C4 + The hydrocarbon feed stream can be recycled to the step of separating the naphtha feed stream.

[0004] CN116023214A discloses a method and system for producing n-alkanes. The method involves contacting isobutane feedstock with an isobutane conversion catalyst in an isobutane conversion unit to carry out an isobutane conversion reaction. The isobutane conversion catalyst has high catalytic activity, is chlorine-free, safe and non-toxic, and reduces corrosion and wear on equipment. The resulting reaction product containing n-alkanes is introduced into a membrane separation unit for membrane separation treatment. The membrane separation element, including a molecular sieve membrane, enables efficient separation of n-alkanes and isoalkanes. The separation efficiency is high and the method is simple and easy to implement.

[0005] The methods described above can all convert small-molecule isoalkanes into n-alkanes, but the energy required for conversion varies depending on the molecular structure of the hydrocarbon. Using a single conversion process is insufficient to effectively guarantee the yield of the target product. Furthermore, ethylene feedstock obtained through hydrogenation processes undergoes a process where organic sulfur is removed and converted into hydrogen sulfide during the hydrogenation reaction, and this hydrogen sulfide is then removed during product separation. Therefore, the sulfur content in ethylene feedstock is typically low, and sulfur injection is necessary before it enters the ethylene cracking furnace to prevent coking of the furnace tubes. Summary of the Invention

[0006] To address the problems existing in the prior art, the purpose of this invention is to provide a method for converting sulfur-containing naphtha. This method uses sulfur-containing naphtha as raw material and can effectively convert isoparaffins in naphtha into ethane, propane, and n-butane, thereby improving the quality of ethylene feedstock.

[0007] This invention provides a method for processing sulfur-containing naphtha, the method comprising:

[0008] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone. The hydroconversion reaction zone is filled with at least two hydroconversion catalyst beds. Along the flow direction, in two adjacent catalyst beds, the mass content of active metal in the downstream catalyst, calculated as oxide, is 1 to 25 percentage points lower than the mass content of active metal in the upstream catalyst, preferably 5 to 15 percentage points.

[0009] (2) The hydrogenation reaction effluent obtained in step (1) is subjected to high-pressure separation to obtain hydrogen-rich gas and liquid effluent. The liquid effluent (hydrogenation reaction product) enters the separation system to separate ethane, propane and n-butane.

[0010] According to the present invention, a fixed-bed reactor is used for the hydrogenation conversion reaction.

[0011] According to the present invention, the n-butane obtained in step (2) can be n-butane-rich, wherein the mass content of n-butane in the n-butane-rich is 95%-100%. Further, step (2) separates ethane and propane, C4... + The above fractions; C4 + The above fractions are further separated to obtain n-butane-rich and isobutane-rich fractions. The n-butane-rich fraction is directly used as a feedstock for ethylene production by steam cracking, while the isobutane-rich fraction is recycled to the inlet of the hydroconversion reaction zone for further recycling and cracking.

[0012] According to the present invention, preferably, the hydroconversion reaction zone is filled with 2 to 3 hydroconversion catalyst beds.

[0013] According to the present invention, along the flow direction, in two adjacent catalyst beds, the ratio of the upstream catalyst loading volume to the downstream catalyst loading volume is 1:3 to 3:1, preferably 1:2 to 2:1.

[0014] According to the present invention, the initial boiling point of the sulfur-containing naphtha is 10-30°C, preferably 15-25°C, and the final boiling point is 50-100°C, preferably 55-70°C.

[0015] According to the present invention, the sulfur in the sulfur-containing naphtha is introduced externally, including organic sulfur and / or inorganic sulfur, wherein the organic sulfur includes one or more of disulfides, thiols and thioethers, and the inorganic sulfur includes hydrogen sulfide.

[0016] According to the present invention, the sulfur content in the sulfur-containing naphtha is 50-20000 mg / kg, preferably 200-10000 mg / kg, for example, it can be 200 mg / kg, 500 mg / kg, 800 mg / kg, 1000 mg / kg, 1500 mg / kg, 2000 mg / kg, 2500 mg / kg, 3000 mg / kg, 3500 mg / kg, 4000 mg / kg, 5000 mg / kg, 6000 mg / kg, 7000 mg / kg, 8000 mg / kg, 9000 mg / kg, 10000 mg / kg, and any range between any two values.

[0017] According to the present invention, the sulfur content in the hydrogenation conversion product is 50-200 mg / kg, preferably 100-200 mg / kg.

[0018] According to the present invention, the sulfur-containing naphtha contains 60 wt% to 90 wt% C5-C6 isoalkanes, preferably 70 wt% to 80 wt%; C7 + The hydrocarbon content is 0–10 wt%, preferably 0.5 wt%–5 wt%; the C5–C6 n-alkanes content is 10 wt%–30 wt%, preferably 15 wt%–25 wt%; C4 - The hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; the cyclic hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; and the total weight of the sulfur-containing naphtha is 100 wt%.

[0019] According to the present invention, the hydroconversion catalyst comprises ZSM-5 molecular sieve and an active metal. In the hydroconversion catalyst, the content of ZSM-5 molecular sieve, based on the weight of the catalyst, is 30 wt% to 80 wt%, preferably 40 wt% to 70 wt%. Further, the SiO2 / Al2O3 molar ratio of the ZSM-5 molecular sieve is 10 to 50, and the specific surface area is 300 to 500 m². 2 / g, with a pore volume of 0.2–0.4 mL / g.

[0020] According to the present invention, the hydroconversion catalyst further includes a binder, preferably alumina. Further, in the hydroconversion catalyst, the binder content, based on the weight of the catalyst, is 5 wt% to 65 wt%, preferably 10 wt% to 35 wt% as an oxide.

[0021] According to the present invention, the active metal component is selected from one or more of Group VIB metals and Group VIII non-noble metals of the periodic table. The Group VIB metals are preferably selected from one or more of molybdenum and tungsten, and the Group VIII non-noble metals are preferably selected from one or more of cobalt and nickel. Further, in the hydroconversion catalyst, based on the weight of the catalyst, the content of the Group VIB metals as oxides is 5 wt% to 30 wt%, preferably 10 wt% to 20 wt%; the content of the Group VIII non-noble metals as oxides is 0.5 wt% to 15 wt%, preferably 3 wt% to 10 wt%.

[0022] According to the present invention, along the flow direction, in two adjacent catalyst beds, the mass content of Group VIB metals as oxides in the downstream catalyst is 1 to 23 percentage points lower (preferably 3 to 15 percentage points lower) than the mass content of Group VIB metals as oxides in the upstream catalyst, and the mass content of Group VIII non-precious metals as oxides in the downstream catalyst is 0 to 4 percentage points lower than the mass content of Group VIII non-precious metals as oxides in the upstream catalyst.

[0023] According to the present invention, the specific surface area of ​​the hydroconversion catalyst is 200-400 m². 2 / g, with a pore volume of 0.20~0.40mL / g.

[0024] According to the present invention, the preparation method of the hydroconversion catalyst can be carried out according to conventional methods in the art. The preparation method includes the preparation of a support and the loading of an active metal component, wherein the preparation process of the support is as follows: a shape-selective cracking molecular sieve and a binder are mechanically mixed, shaped, and then dried and calcined to form a catalyst support. The drying and calcination of the support can be carried out under conventional conditions. The drying conditions are: drying at 100℃~150℃ for 1~12 hours. The calcination conditions are: calcination at 450℃~550℃ for 2.5~6.0 hours.

[0025] According to the present invention, in the preparation method of the hydroconversion catalyst, the method of loading the active metal component is a conventional method, such as kneading, impregnation, etc., with impregnation being preferred. The impregnation method can be a saturated impregnation method, an excess impregnation method, or a complex impregnation method, that is, impregnating the catalyst support with a solution containing the desired active metal component, followed by drying and calcination to obtain the hydroconversion catalyst. The drying conditions are: drying at 100℃~150℃ for 1~12 hours. The calcination conditions are: calcination at 450℃~550℃ for 2.5~6.0 hours.

[0026] According to the present invention, the hydroconversion reaction conditions are as follows: reaction pressure is 0.5 MPa to 10.0 MPa, preferably 2.0 MPa to 5.0 MPa; reaction temperature is 250°C to 500°C, preferably 350°C to 450°C; and liquid hourly space velocity is 0.1 h⁻¹. -1 ~15.0h -1 0.5h is preferred -1 ~5.0h -1 The hydrogen-to-oil volume ratio is 10:1 to 2500:1, preferably 100:1 to 2000:1, and even more preferably 100:1 to 1000:1.

[0027] According to the present invention, the hydrogen-rich gas obtained in step (2) can be used as recycled hydrogen.

[0028] According to the present invention, the separated ethane, propane, and n-butane are fed into a steam cracking unit to produce ethylene, yielding the main target products ethylene, propylene, and butadiene. The triene yields are the ratios of the yields of ethylene, propylene, and butadiene to the total feed, expressed by mass. The operating conditions for the steam cracking to produce ethylene include: a reaction temperature of 860–890°C, a reaction pressure of 0.1–0.3 MPa, and a water-to-oil mass ratio of 0.2–0.6.

[0029] In the hydroconversion process, the first step is the dehydrogenation reaction. Through research, the inventors have discovered that the smaller the molecular weight of the isoalkanes, the more difficult it is for them to undergo the dehydrogenation reaction. Therefore, the hydrogenation performance of the hydroconversion catalyst directly affects the conversion effect of isoalkanes. That is, the stronger the hydrogenation performance of the catalyst, the easier it is to undergo the dehydrogenation reaction, generate carbocations, and then realize the subsequent cracking reaction process.

[0030] Compared with the prior art, the present invention has the following beneficial technical effects:

[0031] (1) The reactivity of hydroconversion catalysts is mainly affected by hydrotreating performance, while the reaction process of isoalkanes is mainly affected by acidic centers, i.e., molecular sieves. The inventors have discovered that ZSM-5 molecular sieves with higher strong acid content tend to undergo cracking reactions during hydroconversion, and can selectively convert isoalkanes in hydrocracking light naphtha into small-molecule n-alkanes. However, existing technologies generally use hydroconversion catalysts with the same metal content, which leads to a decrease in n-alkane yield and a high methane yield as the reaction proceeds. Further research by the inventors has revealed that the method of this invention, by loading hydroconversion catalysts with different active metal contents, and gradually decreasing the active metal content along the stream flow direction, can significantly improve the cracking reaction effect of isoalkanes, increase the yield of small-molecule n-alkanes, and reduce methane generation.

[0032] (2) In the process of producing ethylene by steam cracking, the sulfur content of the feedstock needs to be controlled to a certain extent. If the sulfur content is too low, sulfur needs to be injected before the cracking furnace, otherwise it will accelerate the coking of the ethylene cracking furnace, affecting the operating cycle and cracking effect; while if the sulfur content in the feedstock is too high, it will increase the operating cost of subsequent desulfurization. The inventors have found through research that when producing ethylene feedstock through hydrogenation reaction, by processing sulfur-containing feedstock and controlling the appropriate sulfur content in the hydrogenation products, the sulfur content in the feedstock of the ethylene unit can be effectively controlled, reducing or even eliminating the amount of sulfur injected into the ethylene cracking furnace.

[0033] (3) During the hydrogenation reaction of sulfur-containing hydrocarbon feedstocks, organic sulfides are converted into hydrogen sulfide. This hydrogen sulfide is a worthless product for the hydrogenation unit and may even require removal through separation methods such as stripping. The removed hydrogen sulfide also requires subsequent harmless treatment. When the present invention uses hydrogenation products containing a certain amount of hydrogen sulfide as ethylene feedstock, it can solve the problem of sulfur injection into ethylene production units and simultaneously achieve high-value utilization of the useless components. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process flow according to an embodiment of the present invention;

[0035] Explanation of key figure labels:

[0036] 1-Sulfur-containing naphtha, 2-Hydrogen, 3-Hydroconversion reaction zone, 4-Hydroconversion reaction zone effluent, 5-High-pressure separator, 6-Hydrogen-rich gas phase stream, 7-Liquid phase stream from high-pressure separator, 8-Separation system, 9-Ethane and propane, 10-Isobutane-rich, 11-N-Butane-rich. Detailed Implementation

[0037] The following examples further illustrate the function and effect of the present invention, but the following examples do not constitute a limitation on the method of the present invention.

[0038] Unless otherwise specified, all percentages in this invention refer to mass fractions.

[0039] The method of the present invention, such as Figure 1 As shown, the process includes: sulfur-containing naphtha 1 and hydrogen 2 are mixed and enter the hydroconversion reaction zone 3 for hydroconversion reaction; the hydroconversion reaction effluent 4 enters the high-pressure separator 5; the separated gaseous stream 6 is recycled; the liquid stream 7 enters the separation system 8; and the separated ethane and propane 9, C4 are further processed. + Of the above fractions, ethane and propane 9 are used directly as ethylene feedstock, C4 + The above fractions are further separated to obtain n-butane 11 as ethylene feedstock, and isobutane 10 is recycled to the inlet of hydrogenation conversion reaction zone 3.

[0040] In this invention, the n-butane content of the isolated n-butane is above 96%.

[0041] In this invention, the hydroconversion catalysts in each example are designated as Cat-A followed by a number, such as Cat-A1, Cat-A2, Cat-A3, and Cat-A4. The hydroconversion catalysts were prepared using a conventional active metal saturation impregnation method, and the physicochemical properties of the obtained catalysts are shown in Table 1.

[0042] In this invention, the ZSM-5 molecular sieve used in each example catalyst has a SiO2 / Al2O3 molar ratio of 30 and a specific surface area of ​​400 m². 2 / g, pore volume is 0.25mL / g; the Beta molecular sieve used in each catalyst example has a SiO2 / Al2O3 molar ratio of 30 and a specific surface area of ​​350m². 2 / g, pore volume is 0.3mL / g.

[0043] In this invention, sulfur-containing naphtha is used as hydrocracked light naphtha with added sulfur compounds in each example, and its main properties are shown in Table 3. The sulfur-containing compound is hydrogen sulfide.

[0044] In this invention, the yield of n-alkane = n-alkane yield in hydrogenation conversion products / fresh feed amount × 100%, by mass.

[0045] In this invention, methane yield = methane yield in hydrogenation conversion products / fresh feed amount × 100%, by mass.

[0046] In this invention, n-alkanes include ethane, propane, and n-butane.

[0047] In this invention, the sulfur content of the naphtha itself is less than 5 ppm in each example.

[0048] Example 1

[0049] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0050] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A2 and Cat-A3 along the flow direction;

[0051] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0052] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0053] Example 2

[0054] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0055] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1, Cat-A2 and Cat-A3 along the flow direction;

[0056] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0057] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0058] Example 3

[0059] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0060] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through the hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A2, Cat-A3 and Cat-A4 along the flow direction;

[0061] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0062] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0063] Example 4

[0064] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0065] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1, Cat-A4 and Cat-A5 along the flow direction;

[0066] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0067] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0068] Example 5

[0069] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0070] (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1, Cat-A6 and Cat-A3 along the flow direction;

[0071] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0072] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0073] Example 6

[0074] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0075] (1 Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone for hydroconversion reaction; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1, Cat-A7 and Cat-A3 along the flow direction;

[0076] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0077] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0078] Example 7

[0079] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0080] (1 Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1 and Cat-A6 along the flow direction.

[0081] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0082] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0083] Example 8

[0084] The conversion method of sulfur-containing naphtha adopts, for example Figure 1 The process is shown below. The method specifically includes:

[0085] (1 Sulfur-containing naphtha is mixed with hydrogen and then subjected to a hydroconversion reaction in the hydroconversion reaction zone; the hydroconversion reaction zone is sequentially filled with catalysts Cat-A1 and Cat-A7 along the flow direction.

[0086] (2) The effluent from the hydrogenation conversion reaction in step (1) enters the high-pressure separator. The hydrogen-rich gas obtained is used as recycled hydrogen. The liquid effluent is separated. The ethane, propane and n-butane obtained are used as ethylene feedstock. The isobutane is recycled to the inlet of the hydrogenation conversion reaction zone for recycling cracking.

[0087] The process conditions and hydrogenation effect in this example are shown in Table 4.

[0088] Comparative Example 1

[0089] The difference from Example 1 is that the hydroconversion reaction zone is filled with the hydroconversion catalyst Cat-A2.

[0090] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0091] Comparative Example 2

[0092] The difference from Example 1 is that the hydroconversion reaction zone is sequentially filled with hydroconversion catalysts Cat-B1 and Cat-A1 along the flow direction.

[0093] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0094] Comparative Example 3

[0095] The difference from Example 1 is that the hydrogenation conversion reaction zone is sequentially filled with catalysts Cat-A1 and Cat-A5 along the flow direction.

[0096] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0097] Comparative Example 4

[0098] The difference from Example 1 is that the hydrogenation conversion reaction zone is filled with catalyst Cat-B1.

[0099] The process conditions and hydrogenation effect in this example are shown in Table 5.

[0100] Table 1. Composition and physicochemical properties of hydroconversion catalysts

[0101] Catalyst number Cat-A1 Cat-A2 Cat-A3 Cat-A4 Cat-A5 Cat-A6 Cat-A7 Catalyst properties <![CDATA[Pore volume, cm 3 / g]]> 0.28 0.30 0.31 0.33 0.35 0.32 0.36 <![CDATA[Specific surface area, m 2 / g]]> 296 308 323 335 352 290 361 Catalyst composition ZSM-5, wt% 50 50 50 50 50 45 60 Alumina, wt% 20 25 35 40 46 30 15 <![CDATA[MoO3,wt%]]> 25 20 10 7 3 20 20 NiO, wt% 5 5 5 3 1 5 5

[0102] Table 2 Physicochemical properties of hydroconversion catalysts

[0103]

[0104]

[0105] Table 3. Main Properties of Sulfur-Containing Naphtha

[0106] raw material Sulfur-containing naphtha <![CDATA[C4 isoparaffin content, wt%]]> 1 <![CDATA[Content of n-C4 paraffin, wt%]]> 2 <![CDATA[Content of C5-C6 n-alkanes, wt%]]> 16 <![CDATA[C5-C6 isoparaffin content, wt%]]> 78 <![CDATA[C7 + Hydrocarbon and cyclic hydrocarbon content, wt% 3 Initial boiling point, ℃ 24 Final boiling point, ℃ 64

[0107] Table 4. Process conditions and conversion results of each embodiment

[0108]

[0109] Table 4 continues with the process conditions and conversion results of each embodiment.

[0110]

[0111]

[0112] Table 5. Process conditions and conversion results for each comparative example.

[0113]

[0114] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for processing sulfur-containing naphtha, the method comprising: (1) Sulfur-containing naphtha is mixed with hydrogen and passed through a hydroconversion reaction zone. The hydroconversion reaction zone is filled with at least two hydroconversion catalyst beds. Along the flow direction, in two adjacent catalyst beds, the mass content of active metal in the downstream catalyst, calculated as oxide, is 1 to 25 percentage points lower than the mass content of active metal in the upstream catalyst, preferably 5 to 15 percentage points. (2) The hydrogenation reaction effluent obtained in step (1) is subjected to high-pressure separation to obtain hydrogen-rich gas and liquid effluent. The liquid effluent enters the separation system to separate ethane, propane and n-butane.

2. The processing method according to claim 1, characterized in that, The sulfur content in the sulfur-containing naphtha is 50-20000 mg / kg, preferably 200-10000 mg / kg; And / or, the sulfur content in the hydrogenation conversion product is 50-200 mg / kg, preferably 100-200 mg / kg.

3. The processing method according to claim 1, characterized in that, The initial boiling point of the sulfur-containing naphtha is 10-30℃, preferably 15-25℃, and the final boiling point is 50-100℃, preferably 55-70℃.

4. The processing method according to claim 1, characterized in that, The sulfur-containing naphtha contains 60 wt% to 90 wt% C5-C6 isoalkanes, preferably 70 wt% to 80 wt%; C7 + The hydrocarbon content is 0–10 wt%, preferably 0.5 wt%–5 wt%; the C5–C6 n-alkanes content is 10 wt%–30 wt%, preferably 15 wt%–25 wt%; C4 - The hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; the cyclic hydrocarbon content is 0-10 wt%, preferably 2 wt%-5 wt%; and the total weight of the hydrocracked light naphtha is 100 wt%.

5. The processing method according to claim 1, characterized in that, The hydroconversion reaction zone is filled with 2 to 3 hydroconversion catalyst beds; along the flow direction, in two adjacent catalyst beds, the ratio of the upstream catalyst loading volume to the downstream catalyst loading volume is 1:3 to 3:1, preferably 1:2 to 2:

1.

6. The processing method according to claim 1, characterized in that, The hydroconversion catalyst comprises ZSM-5 molecular sieve and an active metal; the active metal is selected from one or more Group VIB metals and Group VIII non-precious metals, the Group VIB metal is selected from one or more molybdenum and tungsten, and the Group VIII non-precious metal is selected from one or more cobalt and nickel.

7. The processing method according to claim 6, characterized in that, In the hydroconversion catalyst, based on the weight of the catalyst, the content of ZSM-5 molecular sieve is 30wt% to 80wt%, preferably 40wt% to 70wt%; the content of Group VIB metals as oxides is 5wt% to 30wt%, preferably 10wt% to 20wt%; and the content of Group VIII non-noble metals as oxides is 0.5wt% to 15wt%, preferably 3wt% to 10wt%.

8. The processing method according to claim 6 or 7, characterized in that, The hydroconversion catalyst includes a binder, which is preferably alumina; preferably, the binder content, based on the weight of the catalyst, is 5 wt% to 65 wt% as an oxide, more preferably 10 wt% to 35 wt%.

9. The processing method according to claim 6, characterized in that, Along the flow direction, in two adjacent catalyst beds, the mass content of Group VIB metals as oxides in the downstream catalyst is 1 to 23 percentage points lower than that in the upstream catalyst, and the mass content of Group VIII non-precious metals as oxides in the downstream catalyst is 0 to 4 percentage points lower than that in the upstream catalyst.

10. The processing method according to claim 1, characterized in that, The hydrogenation conversion reaction conditions are as follows: reaction pressure is 0.5 MPa to 10.0 MPa, preferably 2.0 MPa to 5.0 MPa; reaction temperature is 250℃ to 500℃, preferably 350℃ to 450℃; liquid hourly space velocity is 0.1 h⁻¹. -1 ~15.0h -1 0.5h is preferred -1 ~5.0h -1 The hydrogen-to-oil volume ratio is 10:1 to 2500:1, preferably 100:1 to 2000:1, and even more preferably 100:1 to 1000:1.

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