Method and device for enhancing hydrogenation depth of polycyclic aromatic hydrocarbon in heavy aromatic oil

Abstract

The invention belongs to the field of chemical engineering and chemical reaction engineering, and provides a method and a device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbon in heavy aromatic oil, the device is composed of a hydrogen and heavy aromatic oil flow control unit, an enhanced mixer series fixed bed reactor unit and a gas-liquid separation unit, and the units are sequentially connected in series through pipelines. The enhanced mixer series fixed bed reactor unit comprises an enhanced mixer, a short-distance taper pipe and a fixed bed reactor which are connected in sequence, a multi-section temperature control electric heating furnace is arranged outside the fixed bed reactor, and the enhanced mixer is integrated to an inlet of the fixed bed reactor through the short-distance taper pipe; the device is used for realizing continuous micron-sized mixing of a gas phase and a liquid phase under the conditions that the hydrogen-oil ratio is higher than 860: 1 and the conversion rate of polycyclic aromatic hydrocarbon is not less than 70%. The hydrogenation depth of the polycyclic aromatic hydrocarbon in the heavy aromatic hydrocarbon oil is improved by forming continuous micron-sized gas-liquid two-phase fluid.

Description

Technical Field

[0001] The invention belongs to the field of chemical engineering and chemical reaction engineering, and in particular, relates to a method and a device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil. Background Art

[0002] Hydrogenation of heavy aromatic oil is an important method for lightening heavy aromatic oil. Through hydrogenation, bicyclic and condensed aromatics such as naphthalene, phenanthrene, and anthracene in heavy aromatic oil are converted into monocyclic aromatics, which are high-quality raw materials for producing high-value chemicals such as benzene, toluene, and xylene. Hydrogenation of heavy aromatic oil is a typical high hydrogen consumption reaction. The gas-liquid mixing effect of hydrogen and heavy aromatic oil and the mass transfer and dissolution of hydrogen in heavy aromatic oil are important factors affecting the efficiency of hydrogenation of heavy aromatic oil. However, the solubility of hydrogen in heavy aromatic oil is low. Therefore, during the deep hydrogenation of heavy aromatic oil, hydrogen in the gas phase needs to be diffused and mass transferred to the active center of the catalyst. In order to improve the efficiency of catalytic hydrogenation of heavy aromatic oil, hydrogenation of heavy aromatic oil is usually completed under high pressure and high hydrogen-to-oil ratio, which significantly increases hydrogen consumption and energy consumption. Especially under mass transfer control or high conversion rate of polycyclic aromatic hydrocarbons, the mass transfer efficiency of gas-phase hydrogen in heavy aromatic oil is a key control factor for improving the depth of hydrogenation of polycyclic aromatic hydrocarbons in heavy aromatic oil.

[0003] At present, hydrogenation reactors are mainly divided into two categories. One is the conventional hydrogenation reactor. The gas-liquid two-phase from the reactor inlet first passes through the inlet distributor, and after rectification in the upper cone, it is diffused to the entire reactor interface after throttling and collision of the two layers of holes in the upper and lower baffles, and then contacts the catalyst bed after distribution through the distribution plate. This distributor and distribution plate can achieve uniform distribution of hydrogen in the bed of the hydrogenation reactor and promote the mixing of the gas-liquid two-phase, but cannot strengthen the mixing of gas and liquid. The other is to change the continuous gas phase into micron-sized bubbles of non-continuous phase through the strengthening device, and then mix it with the continuous oil phase, and use the high specific surface area and surface energy of the micron-sized bubbles to strengthen the mass transfer between the gas and liquid two-phases. Chinese patent CN116790285A discloses a method and device for supergravity enhanced diesel hydrofining, in which a supergravity mixing device is connected in series at the front end of the inlet of the hydrogenation device, and the micro-nano filler on the rotor in the device is used to break the hydrogen under the action of high-speed rotation to form bubbles of 10~200 μm and mix with the liquid phase oil, so as to achieve the purpose of strengthening the mixing and mass transfer of gas-liquid two-phases, thereby improving the efficiency of diesel hydrogenation. Chinese patent CN112175667A discloses a mixed oil hydrogenation micro-interface enhanced reaction system and method, in which a micro-interface generator is used to convert the pressure energy of hydrogen and / or the kinetic energy of liquid into the surface energy of hydrogen bubbles, and the continuous phase hydrogen is broken into 1 μm~1 mm micro-bubbles and then mixed with liquid to achieve enhanced mixing of gas-liquid two-phases, and hydrogen micro-bubbles are used to increase the mass transfer area between gas and liquid phases, strengthen the mass transfer process of hydrogen during the hydrogenation reaction, and strengthen the reaction efficiency between the mixed oil and hydrogen. Chinese patent CN110396425A discloses a device and method for micro-interface enhanced liquid phase circulating hydrogenation, which uses a micro-bubble generator to convert the hydrogen in the continuous phase into micron-sized bubbles and mix them with the liquid in the continuous phase to form a quasi-homogeneous gas-liquid mixed flow. Similarly, the increased mass transfer area between the gas and liquid phases is used to enhance the mixed mass transfer process between hydrogen and liquid raw materials. A large number of micro-bubbles in the liquid phase enhance the mass transfer process of hydrogen dissolving into the liquid phase during the hydrogenation reaction. The space utilization efficiency of the liquid phase circulating hydrogenation reactor is effectively improved. Chinese patent CN110652941A discloses a micro-bubble hydrogenation reactor, which disperses micro-bubbles into the liquid phase oil to increase the mass transfer area between the gas and liquid phases and enhance the mass transfer process between the gas and liquid phases.

[0004] The liquid in the above hydrogenation enhancement reaction is the continuous phase and the microbubbles are the dispersed phase. It is only suitable for reactions with a small hydrogen-to-oil ratio or low hydrogen consumption, and is not suitable for deep hydrogenation reactions of polycyclic aromatic hydrocarbons in heavy aromatic oils with high hydrogen consumption. Summary of the invention

[0005] Aiming at the characteristics of large hydrogen consumption and high hydrogen-to-oil ratio in hydrogenation of polycyclic aromatic hydrocarbons in heavy aromatic hydrocarbons, the present invention proposes a method and device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic hydrocarbon oil. Under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of condensed ring aromatic hydrocarbons is not less than 70%, an enhanced mixer is integrated into the inlet of a fixed bed reactor through a short-distance conical tube. The enhanced mixer is used to change the mixing scale of the gas-liquid two-phase, realize the micron-level mixing of the hydrogen and heavy aromatic hydrocarbon oil two-phases, and improve the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic hydrocarbon oil by forming a continuous micron-level gas-liquid two-phase fluid.

[0006] The purpose of the present invention is achieved by adopting the following technical solutions:

[0007] On the one hand, the present invention provides a device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, which is composed of a hydrogen and heavy aromatic oil metering control unit, an enhanced mixer connected in series with a fixed bed reactor unit and a gas-liquid separation unit, and the units are sequentially connected in series through pipelines. It is characterized in that the enhanced mixer connected in series with the fixed bed reactor unit comprises an enhanced mixer, a short-distance conical tube, and a fixed bed reactor connected in sequence, a multi-stage temperature-controlled electric heating furnace is arranged outside the fixed bed reactor, and the enhanced mixer is integrated into the inlet of the fixed bed reactor through the short-distance conical tube. The device is used to achieve continuous micron-level mixing of gas and liquid phases under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%.

[0008] Furthermore, the dimensions of both ends of the short-distance conical tube match the outlet dimension of the enhanced mixer and the inlet dimension of the fixed bed reactor, respectively, and the length of the short-distance conical tube is 3 to 8 cm, preferably 5 cm. The distance between the enhanced mixer and the fixed bed reactor is short, and the connection through the short-distance conical tube avoids the destruction of the micrometer-scale fluid flow pattern formed in the enhanced mixer, and the gas-liquid two-phase continuous fluid leaving the short-distance conical tube directly enters the catalyst bed, which retains the micrometer-scale flow pattern formed by the gas-liquid two-phase fluid in the mixer to the greatest extent.

[0009] Furthermore, the hydrogen and heavy aromatic oil metering control unit includes a gas feed unit and a liquid feed unit, the gas feed unit includes a gas feed pipe and a pressure reducing valve, a pressure gauge, a stop valve and a gas mass flow meter installed on the gas feed pipe, one end of the gas feed pipe is connected to a gas supply source, the liquid feed unit includes a liquid feed pipe and a stop valve and a liquid metering pump arranged on the liquid feed pipe, one end of the liquid feed pipe is connected to the liquid supply source; the other ends of the gas feed pipe and the liquid feed pipe are both connected to the inlet of the enhanced mixer.

[0010] Furthermore, the fixed bed reactor comprises, from top to bottom, a quartz sand bed layer, a catalyst bed layer, and a quartz sand bed layer.

[0011] Furthermore, the gas-liquid separation unit comprises a high-pressure gas-liquid separator, a low-pressure gas-liquid separator and a liquid storage tank which are connected in sequence, and the outlet of the fixed bed reactor is connected to the inlet of the high-pressure gas-liquid separator.

[0012] Further, the intensified mixer is a mixer capable of achieving two-phase micron-level mixing of hydrogen and heavy aromatic oil under a large hydrogen-to-oil ratio. Further preferably, the mixer is a microchannel mixer or a static mixer, and the microchannel mixer is preferably a separation-recombination type (CPMM) microchannel mixer or a cross-finger type (SIMM) microchannel mixer. The CPMM type microchannel mixer and the SIMM type microchannel mixer are the same as those mentioned in Chinese patent CN117753316A.

[0013] On the other hand, the present invention provides a method for an apparatus for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil. Under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%, hydrogen and heavy aromatic oil are introduced into the inlet of an enhanced mixer through a hydrogen and heavy aromatic oil metering control unit, a continuous fluid of a gas-liquid two-phase micron-level mixture is formed in the enhanced mixer, and then the continuous fluid of the gas-liquid two-phase micron-level mixture is introduced into a catalyst bed of a fixed bed reactor in a downward manner through a short-distance conical tube to undergo a hydrogenation reaction, and the reacted fluid flows out from the outlet of the fixed bed reactor and enters the inlet of a high-pressure gas-liquid separator, and the gas-liquid two-phase separation is performed in the gas-liquid separation unit.

[0014] Furthermore, the heavy aromatic oil contains monocyclic aromatic hydrocarbons, bicyclic aromatic hydrocarbons and condensed-ring aromatic hydrocarbons.

[0015] Furthermore, the micron-scale mixing means that the gas-liquid two-phase mixing scale is ≤10 μm.

[0016] Furthermore, the hydrogen-to-oil ratio is 860 / 1-1200 / 1.

[0017] Furthermore, the mixing conditions in the intensified mixer are: the temperature is -30°C to 300°C, more preferably 50°C to 90°C; and the mixing pressure is the same as that of the fixed bed hydrogenation reactor.

[0018] Furthermore, the conditions of the hydrogenation reaction are: pressure 1 MPa ~ 20 MPa, more preferably 3 MPa ~ 6 MPa; liquid hourly volume space velocity 0.1 h -1 ~5.0 h -1 , and more preferably 0.9 h -1 ~3.5 h -1 ; The reaction temperature is 120°C to 420°C, more preferably 140°C to 300°C,

[0019] Furthermore, the hydrogenation reaction catalyst is a high-activity hydrogenation catalyst, and further, preferably Pt / Al2O3, Pd / Al2O3, Pt-Pd / Al2O3 or a high-activity Ni-based catalyst, and the high-activity Ni-based catalyst is one of Ni / MCM-41, Ni / C and Ni / Al2O3.

[0020] Furthermore, before entering the fixed bed reactor, the gas and liquid phases are simultaneously mixed in an enhanced mixer at the micron level to enhance the mass transfer efficiency between the gas and liquid phases. The rapid diffusion advantage between the micron-level two-phase fluids is utilized to improve the mass transfer process of hydrogen during the reaction, thereby achieving the purpose of increasing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil at a high conversion rate.

[0021] The advantages and beneficial effects of the present invention are:

[0022] (1) The device of the present invention integrates the enhanced mixer into the inlet of the fixed bed reactor through a short-distance conical tube, thereby avoiding the destruction of the micrometer-scale fluid flow pattern formed in the enhanced mixer. The gas-liquid two-phase continuous fluid leaving the short-distance conical tube directly enters the catalyst bed, retaining the micrometer-scale flow pattern formed by the gas-liquid two-phase fluid in the mixer to the greatest extent, thereby improving the hydrogenation depth.

[0023] (2) Under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%, the method of the present invention changes the mixing scale of the gas-liquid two-phase by means of an intensified mixer, thereby achieving micron-level mixing of the hydrogen and heavy aromatic oil two-phases, and enhancing mass transfer by forming a continuous micron-level gas-liquid two-phase fluid, thereby increasing the hydrogenation depth of polycyclic aromatic hydrocarbons in the heavy aromatic oil. The hydrogenation depth of polycyclic aromatic hydrocarbons is higher than that of a conventional fixed-bed hydrogenation reaction unit.

[0024] (3) The method and device of the present invention have a wide range of applications, a simple device structure, and a large range of gas flow rate controllable. In addition to being suitable for gas-liquid-solid three-phase high hydrogen consumption and deep hydrogenation reactions, they are also suitable for deep hydrogenation of organic liquids with faster reaction rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The invention discloses a device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil.

[0026] Figure 2 This is the conventional fixed bed reaction device of Comparative Example 1.

[0027] Among them, Ⅰ-hydrogen and heavy aromatic oil metering control unit, Ⅱ-enhanced mixer in series with fixed bed reactor unit, Ⅱ"-fixed bed reactor unit, Ⅲ-gas-liquid separation unit; 1-pressure reducing valve, 2-pressure gauge, 3-stop valve, 4-gas mass flow meter, 5-liquid metering pump; 6-enhanced mixer, 7-short distance cone, 8-fixed bed reactor, 9-multi-stage temperature-controlled electric heating furnace, 10-high-pressure gas-liquid separator, 11-low-pressure gas-liquid separator, 12-liquid storage tank. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and through specific embodiments. The following embodiments are merely illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0029] Example 1

[0030] like Figure 1 The device shown is for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, which consists of a hydrogen and heavy aromatic oil metering control unit I, an enhanced mixer in series with a fixed bed reactor unit II and a gas-liquid separation unit III, and the units are connected in series in sequence through pipelines.

[0031] The hydrogen and heavy aromatic oil metering control unit I includes a gas feed unit and a liquid feed unit. The gas feed unit includes a gas feed pipe and a pressure reducing valve 1, a pressure gauge 2, a stop valve 3 and a gas mass flow meter 4 installed on the gas feed pipe, and one end of the gas feed pipe is connected to a gas supply source. The liquid feed unit includes a liquid feed pipe and a stop valve 3 and a liquid metering pump 5 arranged on the liquid feed pipe, and one end of the liquid feed pipe is connected to a liquid supply source. The other ends of the gas feed pipe and the liquid feed pipe are both connected to the inlet of the enhanced mixer 6.

[0032] The enhanced mixer-in-series fixed bed reactor unit II comprises an enhanced mixer 6, a short-distance cone tube 7, and a fixed bed reactor 8 connected in sequence. A multi-stage temperature-controlled electric heating furnace 9 is arranged outside the fixed bed reactor 8. The outlet of the enhanced mixer 6 is integrated into the inlet of the fixed bed reactor 8 through the short-distance cone tube 7. The device is used to achieve continuous micron-level mixing of gas and liquid phases under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%. The dimensions at both ends of the short-distance cone tube 7 match the outlet dimension of the enhanced mixer 6 and the inlet dimension of the fixed bed reactor 8, respectively, and the appropriate length is 3 to 8 cm, preferably 5 cm. The distance between the enhanced mixer 6 and the fixed bed reactor 8 is short, and the connection through the short-distance cone tube 7 avoids the destruction of the micron-scale fluid flow pattern formed in the enhanced mixer 6. The gas-liquid two-phase continuous fluid leaving the short-distance cone tube 7 directly enters the catalyst bed layer, which retains the micron-scale flow pattern formed by the gas-liquid two-phase fluid in the enhanced mixer 6 to the greatest extent.

[0033] The fixed bed reactor 8 contains a quartz sand bed layer, a catalyst bed layer, and a quartz sand bed layer in sequence. The gas-liquid separation unit III includes a high-pressure gas-liquid separator 10, a low-pressure gas-liquid separator 11, and a liquid storage tank 12 connected in sequence. The outlet of the fixed bed reactor 8 is connected to the inlet of the high-pressure gas-liquid separator 10. The enhanced mixer 6 is a CPMM type microchannel mixer.

[0034] Comparative Example 1

[0035] like Figure 2 A conventional fixed bed reaction apparatus is shown, which differs from Example 1 only in that the fixed bed reactor unit II" is different, the intensified mixer 6 and the short-distance cone pipe 7 are not installed in front of the fixed bed reactor 8, and the other ends of the gas feed pipe and the liquid feed pipe are connected to the three-way inlet at the inlet of the fixed bed reactor, and the three-way outlet is connected to the inlet of the fixed bed reactor.

[0036] Example 2

[0037] The only difference from Example 1 is that the intensified mixer 6 is a SIMM type microchannel mixer.

[0038] Example 3

[0039] A method for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, wherein the catalytic hydrogenation reaction of tricyclic aromatic hydrocarbon phenanthrene is carried out in a conventional fixed bed reaction device (such as Figure 2 The catalyst in the catalyst bed is a Pt-Pd / Al2O3 catalyst. The catalyst loading conditions are as follows: 1.0 g of a 40-60 mesh Pt-Pd / Al2O3 catalyst precursor is weighed and loaded into a fixed bed reactor 8 with an inner diameter of 4 mm and a length of 270 mm, and both ends of the catalyst precursor are filled with quartz sand. The catalyst reduction conditions are as follows: a hydrogen partial pressure of 1 MPa, a hydrogen flow rate of 100 mL / min, and the temperature is increased to 300 °C at a heating rate of 5 °C / min and maintained for 3 h.

[0040] The hydrogenation reaction conditions were as follows: reaction temperature 180 °C, hydrogen partial pressure 5 MPa, hydrogen-to-oil ratio 900 / 1, liquid hourly volume space velocity 3.33 h -1 .

[0041] Hydrogen and 5% by mass of tricyclic aromatic hydrocarbon phenanthrene / n-decane liquid raw materials were respectively reacted in a conventional fixed bed reactor ( Figure 2) inlet through a tee with a diameter of 3 mm, and micron-level mixing is achieved in the CPMM type microchannel mixer of Example 1 and the SIMM type microchannel mixer of Example 2. The scales of each fluid after mixing in the CPMM type microchannel mixer and the SIMM type microchannel mixer are 0.6 μm and 8 μm, respectively. The mixed fluid enters the fixed bed reactor 8 vertically downward, and the product is taken every 1 hour for analysis after the feed is stable for 2 hours.

[0042] The comparison results of conversion rate and product selectivity of tricyclic aromatic hydrocarbon phenanthrene in three reaction devices are shown in Table 1.

[0043] Table 1 Comparison of conversion rate and product selectivity of tricyclic aromatic phenanthrene in three reaction devices

[0044]

[0045] Under the condition of high phenanthrene conversion rate (phenanthrene conversion rate in three reaction units is greater than 98%), compared with the conventional fixed bed hydrogenation reaction unit, the selectivity of full hydrogen phenanthrene in the fixed bed reaction unit with CPMM and SIMM type microchannel mixer in front increased by 1.3% and 0.6% respectively; the selectivity of octahydro phenanthrene increased by 5.8% and 4.5% respectively; the selectivity of tetrahydro phenanthrene decreased by 0.4% and 0.5% respectively; the selectivity of dihydro phenanthrene decreased by 6.7% and 4.6% respectively. The hydrogenation depth of phenanthrene in the fixed bed reactor with CPMM and SIMM type micro mixer in front was higher than that in the conventional fixed bed reactor.

[0046] Example 4

[0047] A method for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, wherein the catalytic hydrogenation reaction of bicyclic aromatic hydrocarbon naphthalene is carried out in a conventional fixed bed reaction device (such as Figure 2 The method of achieving the method of enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil of Example 1 and Example 2 is carried out in the device. The catalyst in the catalyst bed and its loading method and reduction conditions are the same as those in Example 3. The gas-liquid mixing method and the scale of each fluid after mixing are the same as those in Example 3. The reaction conditions are: reaction temperature 200 ° C, hydrogen partial pressure 5 MPa, hydrogen-to-oil ratio 900 / 1, liquid hourly volume space velocity 3.33 h -1 The liquid raw material is a 5% by mass solution of bicyclic aromatic hydrocarbon naphthalene / n-decane. The liquid product sampling and analysis conditions are the same as those in Example 3.

[0048] The comparison results of conversion rate and product selectivity of bicyclic aromatic naphthalene in three reaction devices are shown in Table 2.

[0049] Table 2 Comparison of conversion rate and product selectivity of bicyclic aromatic naphthalene in three reaction devices

[0050]

[0051] Under the condition of 100% conversion of dicyclic aromatics, compared with the conventional fixed bed hydrogenation reactor, the fixed bed hydrogenation reactor with CPMM type microchannel mixer and SIMM type microchannel mixer in front increased the selectivity of decalin by 9.0% and 6.8% respectively; and reduced the selectivity of tetralin by 9.0% and 6.8% respectively. The hydrogenation depth in the fixed bed reactor with CPMM type microchannel mixer and SIMM type micromixer in front was higher than that in the conventional fixed bed reactor.

[0052] Example 5

[0053] A method for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, wherein the heavy aromatic oil (the heavy aromatic oil is provided by Zhejiang Petrochemical Co., Ltd., and the contents of total cycloalkanes, total monocyclic aromatic hydrocarbons, total bicyclic aromatic hydrocarbons and total tricyclic aromatic hydrocarbons in the heavy aromatic raw material are 0.1%, 46.5%, 28.0% and 25.4%, respectively) is subjected to catalytic hydrogenation reaction in a conventional fixed bed reactor (such as Figure 2 The catalyst and reduction conditions are the same as those in Example 3. The gas-liquid mixing method and the scale of each fluid after mixing are the same as those in Example 3. The catalyst loading conditions are as follows: 1.7 g of 40-60 mesh PtPd / Al2O3 precursor is weighed and loaded into a constant temperature reaction tube with an inner diameter of 4 mm and a length of 270 mm, and both ends of the catalyst precursor are filled with quartz sand.

[0054] The hydrogenation reaction conditions were: reaction temperature 300 °C, hydrogen partial pressure 5 MPa, hydrogen-to-oil ratio 900 / 1, liquid hourly volume space velocity 1.98 h -1 .

[0055] The comparative results of the conversion rates of total tricyclic aromatics and total dicyclic aromatics in heavy aromatic oil in three reaction units are shown in Table 3.

[0056] Table 3 Comparison of the conversion rates of aromatics in heavy aromatic oil feedstock in three reaction units

[0057]

[0058] Under the condition that the total aromatic conversion rate is higher than 75%, compared with the conventional fixed-bed hydrogenation reactor, the fixed-bed reactor with the CPMM type microchannel mixer and SIMM type microchannel mixer in front increased the total tricyclic aromatic conversion rate in heavy aromatic oil by 8.2% and 7.9%, respectively; the total dicyclic aromatic conversion rate in heavy aromatic oil decreased by 0.9% and 7.5%, respectively. The hydrogenation depth of the fixed-bed reactor with the CPMM type microchannel mixer and SIMM type microchannel mixer in front was higher than that of the conventional fixed-bed reactor.

[0059] The present invention has been described above to clearly disclose the key equipment and process technology solutions of the present invention. However, it is clear to those skilled in the art that some modifications and improvements can be made to the present invention. Therefore, as long as they do not depart from the spirit of the present invention, any modifications and improvements made to the present invention should be within the scope of the present invention. The scope of the present invention is set forth in the attached claims.

Claims

1. A device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil, comprising a hydrogen and heavy aromatic oil metering control unit (I), an enhanced mixer connected in series with a fixed bed reactor unit (II) and a gas-liquid separation unit (III), wherein the units are sequentially connected in series through pipelines, characterized in that: The intensified mixer-in-series fixed bed reactor unit (II) comprises an intensified mixer (6), a short-distance conical tube (7), and a fixed bed reactor (8) connected in sequence. A multi-stage temperature-controlled electric heating furnace (9) is arranged outside the fixed bed reactor (8). The intensified mixer (6) is integrated into the inlet of the fixed bed reactor (8) via the short-distance conical tube (7). The device is used to achieve continuous micron-level mixing of gas phase and liquid phase under the conditions that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%.

2. The device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to claim 1, characterized in that: The dimensions of both ends of the short-distance conical tube (7) respectively match the outlet dimension of the intensified mixer (6) and the inlet dimension of the fixed bed reactor (8), and the length of the short-distance conical tube (7) is 3 to 8 cm.

3. The device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to claim 1, characterized in that: The hydrogen and heavy aromatic oil metering control unit (I) comprises a gas feed unit and a liquid feed unit. The gas feed unit comprises a gas feed pipe and a pressure reducing valve (1), a pressure gauge (2), a stop valve (3) and a gas mass flow meter (4) installed on the gas feed pipe. One end of the gas feed pipe is connected to a gas supply source. The liquid feed unit comprises a liquid feed pipe and a stop valve (3) and a liquid metering pump (5) arranged on the liquid feed pipe. One end of the liquid feed pipe is connected to a liquid supply source. The other ends of the gas feed pipe and the liquid feed pipe are both connected to the inlet of an enhanced mixer (6).

4. The device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to claim 1, characterized in that: The fixed bed reactor (8) comprises, from top to bottom, a quartz sand bed layer, a catalyst bed layer, and a quartz sand bed layer.

5. The device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to claim 1, characterized in that: The gas-liquid separation unit (III) comprises a high-pressure gas-liquid separator (10), a low-pressure gas-liquid separator (11) and a liquid storage tank (12) which are connected in sequence, and the outlet of the fixed bed reactor (8) is connected to the inlet of the high-pressure gas-liquid separator (10).

6. The device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to claim 1, characterized in that: The intensified mixer (6) is a mixer capable of achieving micron-level mixing of hydrogen and heavy aromatic oil under conditions of a large hydrogen-to-oil ratio.

7. A method for the device for enhancing the hydrogenation depth of polycyclic aromatic hydrocarbons in heavy aromatic oil according to any one of claims 1 to 6, characterized in that: Under the condition that the hydrogen-to-oil ratio is higher than 860:1 and the conversion rate of polycyclic aromatic hydrocarbons is not less than 70%, hydrogen and heavy aromatic oil are introduced into the inlet of the enhanced mixer (6) through the hydrogen and heavy aromatic oil metering control unit (I), and a continuous fluid of a gas-liquid two-phase micron-level mixture is formed in the enhanced mixer (6). The continuous fluid of the gas-liquid two-phase micron-level mixture is then introduced into the catalyst bed of the fixed bed reactor (8) in a downward manner through a short-distance conical tube (7) to undergo a hydrogenation reaction. The fluid after the reaction flows out from the outlet of the fixed bed reactor (8) and enters the inlet of the high-pressure gas-liquid separator (10), and the gas-liquid two-phase separation is carried out in the gas-liquid separation unit (III).

8. The method according to claim 7, characterized in that The micron-scale mixing means that the gas-liquid two-phase mixing scale is ≤10 μm.

9. The method according to claim 7, characterized in that: The mixing conditions in the enhanced mixer (6) are: temperature of -30°C to 300°C, and mixing pressure is the same as that of the fixed bed hydrogenation reactor.

10. The method according to claim 7, characterized in that The conditions of the hydrogenation reaction are: pressure 1-20 MPa, liquid hourly volume space velocity 0.1-5.0 h -1 , the reaction temperature is 140°C~300°C; the catalyst for the hydrogenation reaction is a high-activity hydrogenation catalyst, selected from one of Pt / Al2O3, Pd / Al2O3, Pt-Pd / Al2O3, and a high-activity Ni-based catalyst.

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