Production process for full circulation of aviation kerosene components of hydrocracking unit

Abstract

A hydrocracking unit aviation kerosene component full-cycle production process relates to the technical field of medium-pressure hydrocracking, and comprises the following steps: S1, mixing raw oil with hydrogen, and feeding from the top of a hydrogenation pre-refining reaction zone; s2, feeding a coker gasoline raw material from the middle lower part of the hydrogenation pretreatment reaction zone; s3, mixing the effluent of the hydrogenation pre-refining reaction zone with liquefied gas, and allowing the mixture to enter a hydrocracking reaction zone for reaction; s4, enabling effluent of the hydrocracking reaction zone to enter a separation system; liquid phase separation effluent at the bottom of the separation tower enters a fractionation system, and aviation kerosene components, light naphtha, heavy naphtha and diesel oil are sequentially discharged from top to bottom; s5, returning the aviation kerosene component and the diesel oil to the raw material tank through a residual oil hydrogenation device, and carrying out cracking reaction again; the aviation kerosene component is returned to the raw material tank again, and the cracking reaction is performed for the second time to produce the naphtha component; the problems of nowhere to remove the aviation kerosene components and shortage of naphtha can be solved at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of medium-pressure hydrocracking, and in particular to a production process for full circulation of aviation kerosene components in a hydrocracking unit. Background Art

[0002] The main products of the hydrocracking unit include light naphtha, heavy naphtha, jet fuel components, and diesel that meets the national sixth-stage standard. The existing medium-pressure hydrocracking technology (RMC-Ⅱ) optimizes the output ratio of naphtha and jet fuel in design, with the yield of naphtha being 33.9% and the yield of jet fuel being as high as 42.64%. This technical feature makes the unit highly efficient in producing jet fuel.

[0003] However, in actual operation, the production of refined oil will be adjusted according to changes in market demand. For example, if the market demand for jet fuel drops significantly, the jet fuel component originally used to produce jet fuel components may be re-purposed and used as part of the diesel blending component. However, this conversion is not without challenges, because the addition of jet fuel components to diesel may cause the wear scar diameter and acidity indicators of refined diesel in the tank area to become unstable, which in turn affects the quality stability and market competitiveness of the entire finished diesel pool.

[0004] In addition, the naphtha produced by the hydrocracking unit contains a high potential content of aromatics, which makes it a high-quality reforming raw material. When the price of triphenyl compounds in the market rises, the hydrogen supply gap problem faced by enterprises becomes more urgent, so solving the shortage of reforming raw materials, namely naphtha, has become a top priority. If the cost of reforming raw materials is higher than diesel, converting excess jet fuel components into naphtha to replace part of the diesel blending components can not only effectively alleviate the pressure of raw material shortages, but also bring significant economic benefits to enterprises.

[0005] In order to better meet these challenges, research and practice on how to utilize existing equipment processes to efficiently convert jet fuel components into naphtha components has become one of the key issues that need to be addressed urgently. Summary of the invention

[0006] In order to overcome the deficiencies in the background technology, the present invention discloses a production process for full circulation of aviation kerosene components in a hydrocracking unit.

[0007] In order to achieve the above-mentioned invention object, the present invention adopts the following technical scheme: A production process for full circulation of aviation fuel components in a hydrocracking unit, comprising the following steps: S1. Vacuum light wax oil, catalytic cracking diesel oil and straight-run diesel oil are input into a raw material tank and mixed into raw material oil; a microwave heating device is provided in the raw material tank; after the raw material oil is mixed with hydrogen, the raw material oil is fed from the top of the hydrogenation pre-refining reaction zone; S2. Feed the coking gasoline raw material from the lower middle part of the hydrogenation pretreatment reaction zone, and the height of the feed position from the bottom of the last catalyst bed in the hydrogenation pre-refining reaction zone accounts for 15% to 30% of the total height of the reaction zone; control the outlet temperature of the hydrogenation pre-refining reaction zone at 380°C to 400°C; S3, mixing the effluent from the hydrogenation pre-refining reaction zone with the liquefied gas and then entering the hydrocracking reaction zone for reaction; S4, the effluent from the hydrocracking reaction zone enters the separation system, hydrogen is separated from the top of the separation tower, and circulated back to the hydrogenation pre-refining reaction zone and the hydrocracking reaction zone as circulating hydrogen; the liquid phase separation effluent at the bottom of the separation tower enters the fractionation system, and jet fuel components, light naphtha, heavy naphtha and diesel are discharged in sequence from top to bottom; S5. Return the jet fuel components and diesel to the raw material tank through the residue oil hydrogenation unit for another cracking reaction.

[0008] Preferably, in step S1, the hydrogenation pre-refining reaction zone is filled with a refined catalyst, the catalyst comprises a carrier and a hydrogenation metal component, and the carrier can be selected from one or more of alumina, amorphous silica-alumina, silicon dioxide, titanium oxide and the like.

[0009] Preferably, in step S2, the feed mass ratio of the coker gasoline feedstock to the diesel feedstock is 6:1 to 3:1.

[0010] Preferably, in step S2, the average reaction temperature of the hydrogenation pre-refining reaction zone is 260°C to 370°C, the inlet hydrogen-oil volume ratio is 350:1 to 900:1, the operating pressure is 6.0MPa to 10.0MPa, and the liquid hourly volume space velocity is 0.3h - ¹~5.0h - ¹.

[0011] Preferably, in step S3, the hydrocracking reaction zone is loaded with a hydrocracking catalyst, the catalyst comprising a carrier and a hydrogenation metal, the carrier contains a molecular sieve, and the hydrogenation metal is selected from one or more of Group VI, Group VII, Group VIII metals, metal oxides or metal sulfides.

[0012] Preferably, in step S3, a plurality of hydrocracking catalyst beds are provided in the hydrocracking reaction zone, and two adjacent hydrocracking catalyst beds are separated by a cold hydrogen box.

[0013] Due to the adoption of the above-mentioned technical solution, the present invention has the following beneficial effects: The present invention discloses a production process for full circulation of aviation kerosene components in a hydrocracking unit, which has a simple structure. On the basis of the existing process, a connecting line between a jet fuel cracking outlet unit and a residual oil hydrotreating unit is used to return the aviation kerosene to a pipeline of a jet fuel cracking inlet unit, thereby realizing full circulation of the jet fuel cracking. The aviation kerosene components are returned to a feedstock tank again for a second cracking reaction to produce naphtha components. When the market demand for jet fuel decreases, the problem of having nowhere to go for the jet fuel components and the shortage of naphtha can be solved at the same time. DETAILED DESCRIPTION

[0014] The present invention can be explained in detail through the following embodiments. The purpose of disclosing the present invention is to protect all technical improvements within the scope of the present invention. In the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they are only corresponding to the present application and are for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction.

[0015] Example 1, a production process for full circulation of aviation kerosene components in a hydrocracking unit, comprising the following steps: S1. Vacuum light wax oil, catalytic cracking diesel and straight-run diesel are input into a raw material tank and mixed into raw material oil. After the raw material oil is mixed with hydrogen, it is fed from the top of the hydrogenation pre-refining reaction zone. The role of hydrogen is to provide a hydrogen source to promote the occurrence of subsequent hydrogenation reactions, such as hydrodesulfurization, hydrodenitrogenation and aromatic saturation, thereby improving product quality. The mixed materials enter from the top of the hydrogenation pre-refining reaction zone, and the harmful impurities in the raw materials, such as sulfur and nitrogen compounds, are removed through the action of the refining catalyst to improve the purity of the raw materials. The hydrogenation pre-refining reaction zone is filled with a refining catalyst, the catalyst includes a carrier and a hydrogenation metal component, and the carrier can be selected from one or more of alumina, amorphous silica-alumina, silicon dioxide, titanium oxide, etc.; a microwave heating device is provided in the raw material tank, and the microwave heating device acts on the raw material oil to crack its macromolecules to form smaller molecules, thereby improving the lightweight level of the raw material oil, thereby reducing the pressure of the subsequent hydrogenation process and improving the reaction efficiency.

[0016] S2. Feed the coking gasoline raw material from the lower middle part of the hydrogenation pretreatment reaction zone. The feed mass ratio of the coking gasoline raw material to the diesel raw material is 6:1 to 3:1. The height of the feed position from the bottom of the last catalyst bed in the hydrogenation pre-refining reaction zone accounts for 15% to 30% of the total height of the reaction zone. The average reaction temperature of the hydrogenation pre-refining reaction zone is 260°C to 370°C, the inlet hydrogen-oil volume ratio is 350:1 to 900:1, the operating pressure is 6.0MPa to 10.0MPa, and the liquid hourly volume space velocity is 0.3h - ¹~5.0h - ¹; Control the outlet temperature of the hydrogenation pre-refining reaction zone at 380℃~400℃.

[0017] S3, mixing the effluent from the hydrogenation pre-refining reaction zone with the liquefied gas and then entering the hydrocracking reaction zone for reaction; the hydrocracking reaction zone is loaded with a hydrocracking catalyst, the catalyst comprising a carrier and a hydrogenation metal, the carrier containing a molecular sieve, and the hydrogenation metal is selected from one or more of Group VI, Group VII, Group VIII metals, metal oxides or metal sulfides; S4. The effluent from the hydrocracking reaction zone enters the separation system, and hydrogen is separated at the top of the separation tower and circulated back to the hydrogenation pre-refining reaction zone and the hydrocracking reaction zone as circulating hydrogen; a membrane separation device is installed on the top of the separation tower to preliminarily separate hydrogen and other gases. Then, the preliminarily separated hydrogen is sent to the pressure swing adsorption system, and the hydrogen can be further purified through periodic high-pressure adsorption and low-pressure desorption processes; the membrane separation device can efficiently separate hydrogen from the mixed gas, and the pressure swing adsorption system can adsorb impurity gases under high pressure and release hydrogen under low pressure. The combination of the two can achieve efficient hydrogen recovery and purification; The liquid phase separation effluent at the bottom of the separation tower enters the fractionation system, and jet fuel components, light naphtha, heavy naphtha and diesel are discharged from top to bottom in sequence; multiple hydrocracking catalyst beds are set in the hydrocracking reaction zone, and two adjacent hydrocracking catalyst beds are separated by a cold hydrogen box; that is, hydrogen is separated from the liquid product by a physical separation method, and it is returned to the reaction system as circulating hydrogen for use, which not only saves costs but also improves the utilization rate of hydrogen; the liquid phase material at the bottom of the separation tower enters the fractionation system, and is graded and separated according to the different boiling points of each component to obtain products of different specifications; the design of the multi-stage catalyst bed combined with the use of the cold hydrogen box can effectively adjust the reaction temperature and prevent the catalyst from being deactivated due to local overheating; S5. Return the jet fuel components and diesel to the raw material tank through the residue oil hydrogenation unit for cracking reaction again. The recycling process helps to improve the raw material conversion rate of the overall process and increase the naphtha yield.

[0018] Example 2, a production process for full circulation of aviation kerosene components in a hydrocracking unit, wherein vacuum light wax oil, catalytic cracking diesel, and straight-run diesel are mixed in a feed mass ratio of 3:2:5, and then fed from the top of the hydropre-refining reaction zone, with an inlet hydrogen-to-oil volume ratio of 600:1; coking gasoline feedstock is fed from the middle and lower part of the hydropretreatment reaction zone, with a feed mass ratio of coking gasoline feedstock to diesel feedstock of 5:1, and the height of the feed position from the bottom of the last catalyst bed in the hydropre-refining reaction zone accounts for 25% of the total height of the reaction zone; the average reaction temperature of the hydropre-refining reaction zone is 344°C, the operating pressure is 9.5MPa, and the liquid hourly volume space velocity is 2.0h - ¹; Control the outlet temperature of the hydrogenation pre-refining reaction zone at 380℃; The effluent from the hydrogenation pre-refining reaction zone is mixed with liquefied gas and then enters the hydrocracking reaction zone for reaction; the catalyst is selected as FF-66, the content of the Group VI metal component in terms of metal oxide is 10wt%, and the content of the Group VIII metal in terms of metal oxide is 1.1wt%; the catalyst is selected as FC-50, the content of the hydrogenation metal in terms of oxide is 14wt%, and the content of the molecular sieve is 10wt%; 4 hydrocracking catalyst beds are set, and each bed is separated by a cold hydrogen box; The effluent from the hydrocracking reaction zone enters the separation system, and hydrogen is separated at the top of the separation tower and circulated back to the hydrogenation pre-refining reaction zone and the hydrocracking reaction zone as circulating hydrogen; the liquid phase separation effluent at the bottom of the separation tower enters the fractionation system, the top temperature of the fractionation tower is 155°C, the bottom temperature is 305°C, and the reflux ratio is 0.8; the jet fuel component is extracted from the fractionation tower, returned to the feed tank through the residue oil hydrogenation device, and then mixed with the feed oil before entering the hydrocracking reaction zone again; the reaction result is a heavy naphtha yield of 92.5%, energy consumption is reduced by 10% compared with the traditional process, and the catalyst life is extended by 15%.

[0019] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive, and it is intended that all changes that fall within the meaning and scope of equivalent elements are included in the present invention.

Claims

1. A production process for full circulation of aviation fuel components in a hydrocracking unit, characterized by: comprising: Follow these steps: S1. Vacuum light wax oil, catalytic cracking diesel oil and straight-run diesel oil are input into a raw material tank and mixed into raw material oil; a microwave heating device is provided in the raw material tank; after the raw material oil is mixed with hydrogen, the raw material oil is fed from the top of the hydrogenation pre-refining reaction zone; S2. Feed the coking gasoline raw material from the lower middle part of the hydrogenation pretreatment reaction zone, and the height of the feed position from the bottom of the last catalyst bed in the hydrogenation pre-refining reaction zone accounts for 15% to 30% of the total height of the reaction zone; control the outlet temperature of the hydrogenation pre-refining reaction zone at 380°C to 400°C; S3, mixing the effluent from the hydrogenation pre-refining reaction zone with the liquefied gas and then entering the hydrocracking reaction zone for reaction; S4, the effluent from the hydrocracking reaction zone enters the separation system, hydrogen is separated from the top of the separation tower, and circulated back to the hydrogenation pre-refining reaction zone and the hydrocracking reaction zone as circulating hydrogen; the liquid phase separation effluent at the bottom of the separation tower enters the fractionation system, and jet fuel components, light naphtha, heavy naphtha and diesel are discharged in sequence from top to bottom; S5. Return the jet fuel components and diesel to the raw material tank through the residue oil hydrogenation unit for cracking reaction again.

2. The full-cycle production process of aviation kerosene components in a hydrocracking unit according to claim 1, characterized in that: In step S1, the hydrogenation pre-refining reaction zone is filled with a refined catalyst, the catalyst comprising a carrier and a hydrogenation metal component, and the carrier can be selected from one or more of alumina, amorphous silica-alumina, silicon dioxide, titanium oxide, and the like.

3. The full-cycle production process of aviation kerosene components in a hydrocracking unit according to claim 1, characterized in that: In step S2, the feed mass ratio of the coker gasoline feedstock to the diesel feedstock is 6:1 to 3:

1.

4. The full-cycle production process of aviation kerosene components in a hydrocracking unit according to claim 1, characterized in that: In step S2, the average reaction temperature of the hydrogenation pre-refining reaction zone is 260°C to 370°C, the inlet hydrogen-oil volume ratio is 350:1 to 900:1, the operating pressure is 6.0MPa to 10.0MPa, and the liquid hourly volume space velocity is 0.3h - ¹~5.0h - ¹.

5. The full-cycle production process of aviation kerosene components in a hydrocracking unit according to claim 1, characterized in that: In step S3, the hydrocracking reaction zone is filled with a hydrocracking catalyst, the catalyst comprising a carrier and a hydrogenation metal, the carrier contains a molecular sieve, and the hydrogenation metal is selected from one or more of Group VI, Group VII, Group VIII metals, metal oxides or metal sulfides.

6. The full-cycle production process of aviation kerosene components in a hydrocracking unit according to claim 1, characterized in that: In step S3, a plurality of hydrocracking catalyst beds are arranged in the hydrocracking reaction zone, and two adjacent hydrocracking catalyst beds are separated by a cold hydrogen box.