A waste mineral oil hydrotreating system and method

Abstract

A waste mineral oil hydrotreating system and method, comprising a filtration unit, a hot hydrogen flash evaporation unit and a hydrogenation reaction unit sequentially arranged along the flow direction of the feedstock oil. The filtration unit is used to filter out particulate impurities larger than 25 μm in the feedstock oil; the hot hydrogen flash evaporation unit is used to heat the feedstock oil to a preset temperature with hot hydrogen and then carry out the reaction coupling and removal of metals and asphaltenes, and then carry out flash separation; the hydrogenation reaction unit is used to remove metals, organic chlorine and sulfur and nitrogen impurities in the feedstock oil; the clean oil product after being treated by the above units in sequence is subjected to deep hydrogenation treatment to obtain a higher-quality base oil, or directly used as a base oil blending component and a fuel oil product. This application organically couples the pretreatment and hydrogenation processes, and simultaneously carries out the pretreatment and hydrorefining of waste mineral oil under the condition of hydrogen, which not only avoids the problem of easy coking in the traditional heating furnace heating, but also can maintain the catalyst activity in the hydrogenation process and extend the operation cycle of the device.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste mineral oil recovery and treatment, and particularly relates to a waste mineral oil hydrotreating system and method. Background Art

[0002] Traditional waste mineral oil recovery technologies mainly include acid-base washing, solvent refining + clay refining. The problems thereof are large solvent loss, low base oil yield, high sulfur content in the base oil product, poor blendability of the product, large energy consumption and environmental pollution, etc.

[0003] Hydrorefining technology has only been industrialized in recent years. It is similar to traditional oil hydrotreating technology, which means that in the presence of hydrogen pressure and catalyst, harmful impurities such as sulfur, oxygen, and nitrogen in the oil are converted into corresponding hydrogen sulfide, water, ammonia and removed, and olefins and diolefins are hydrogenated and saturated, and part of the aromatics are hydrogenated and saturated to improve the quality of the oil. The base oil after hydrorefining can meet the standard of type II base oil, and the product value is greatly improved.

[0004] However, at present, the problems of waste mineral oil hydrorefining technology mainly focus on the easy coking of waste mineral oil during the heating process, resulting in pipeline and equipment blockage, too fast deactivation rate of the hydrotreating catalyst, short operation cycle of the device, etc.; various impurities in waste mineral oil have a great impact on the catalyst life, and the catalyst in some hydrotreating units becomes deactivated within a few days and cannot continuously produce. Therefore, in the pretreatment stage before hydrogenation, it is necessary to effectively remove the impurities that affect the catalyst through certain physical or chemical means to ensure the normal progress of the subsequent hydrogenation process.

[0005] The traditional hydrorefining pretreatment technologies mainly include the following:

[0006] 1) Filtration - centrifugation - flash evaporation - vacuum technology: The general process is that first, the raw oil is centrifuged or mechanically filtered and heated for dehydration and deslagging; the raw oil after deslagging is heated in a heating furnace, and after reaching a certain temperature, it is pre-flashed to remove water and light components and then subjected to vacuum distillation. The pretreated raw material drawn from the side line of the vacuum tower is then subjected to subsequent hydrorefining. The principle of this pretreatment process is mainly to remove heavy components through mechanical methods and fractionation principles, but impurities such as gum, metal, chlorine, and sulfur in the raw material are not removed, which affects the subsequent hydrotreating process.

[0007] 2) Acid and alkali washing - clay refining: The general process is to use the strong oxidizing property of concentrated sulfuric acid to forcibly oxidize the impurities in waste mineral oil to form flocs for precipitation and separation, then neutralize with alkali and add clay for decolorization and filtration, and finally obtain the refined product. Due to high pollution, high product loss, great harm to the health of operators, and poor blendability of the produced product, this process has been phased out and is usually used in small-scale plants. At present, some waste oil recycling enterprises still use this technology for operation without alternative processes;

[0008] 3) Solvent refining: This technology belongs to the traditional type I lubricating oil refining process and can also be used in non-mineral oil refining. In the process of non-mineral oil solvent refining, the selected solvent has a high solubility for impurities and non-ideal components in the oil, while having a low solubility for the ideal components in the oil. The non-ideal components are removed through liquid-liquid extraction. Common solvents for refining waste mineral oil include furfural, phenol, and N-methylpyrrolidone, etc. The waste mineral oil after solvent refining is further refined by adsorbing and decolorizing with activated clay. This process route can only produce low-grade type I base oil products at present, and the production process requires chemical solvents, resulting in high production costs and environmental protection problems such as difficult treatment of waste solvents and waste clay.

[0009] Therefore, traditional pretreatment processes such as fine filtration, atmospheric and vacuum distillation, flash distillation, and clay refining and other physical methods cannot effectively remove harmful metals, chlorine, nitrogen, asphaltenes, additives and other harmful impurities at present. At the same time, the product yields of these conventional methods are low, and some high-value base oil components flow into low-value by-products such as heavy fuel oil; secondly, traditional chemical methods such as acid and alkali washing, solvent refining, and clay refining mostly use chemical agents such as acid-base solutions and organic solvents, and a large amount of harmful chemical waste liquid is generated during the production process, which needs to be recycled or discharged up to standard; at the same time, these chemical methods can only remove some harmful components in the feedstock oil such as asphaltenes, and other metal elements, organic chlorine, sulfur and nitrogen and other impurities still cannot be removed. Summary of the Invention

[0010] Aiming at the problems of easy coking during the heating process of waste mineral oil in the hydrogenation process of waste mineral oil, too fast deactivation rate of the catalyst during the hydrogenation process, short operation cycle of the device, and unqualified product quality, the present invention provides a waste mineral oil hydrotreating system and method, which organically couples the pretreatment and hydrogenation processes, and simultaneously performs waste mineral oil pretreatment and hydrorefining under hydrogenation conditions, not only avoiding the problem of easy coking in the traditional heating furnace heating, but also maintaining the activity of the catalyst during the hydrogenation process, extending the operation cycle of the device. The high-quality pretreatment products produced can be used as raw materials for deep hydrotreating to produce high-quality base oils, or directly used as blending components of low-quality base oils or fuel oil products.

[0011] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0012] A waste mineral oil hydrotreating system includes a filtration unit, a hot hydrogen flash evaporation unit, a hydrogenation reaction unit, and a high-pressure separation unit arranged in sequence along the flow direction of the feedstock oil.

[0013] The filtration unit is used to filter out particulate impurities larger than 25 μm in the feedstock oil.

[0014] The hot hydrogen flash evaporation unit includes a suspension bed reactor and a hot hydrogen flash tank connected in sequence. A hot hydrogen supply pipeline and a feedstock oil pipeline are arranged in parallel upstream of the suspension bed reactor. A catalyst addition pipeline is connected to the feedstock oil pipeline. The suspension bed reactor realizes effective dispersion and mixing of the dispersed catalyst, hydrogen, and feedstock oil through different inlet flow channels, thereby achieving the reaction coupling and removal of metals and asphaltenes. The hot hydrogen flash tank is used to separate the asphaltene and heavy components carried in the feedstock oil. A hot oil circulation pipeline is led out from the middle of the hot hydrogen flash tank and is connected back to the hot hydrogen supply pipeline.

[0015] The hydrogenation reaction unit is used to remove metals, organic chlorine, and sulfur and nitrogen impurities in the feedstock oil, and includes a hydrogenation reactor, in which a hydrogenation catalyst is installed.

[0016] The high-pressure separation unit is used for separating oil and gas in the effluent from the hydrogenation reaction.

[0017] The clean oil product after being treated by the above units in sequence is subjected to deep hydrogenation treatment to obtain a higher-quality base oil, or directly used as a base oil blending component and a fuel oil product.

[0018] In some technical solutions, the hot hydrogen flash evaporation unit further includes a first heat exchanger and a vacuum tower arranged downstream of the hot hydrogen flash tank. The first heat exchanger is connected to the gas-phase outlet of the hot hydrogen flash tank and is used to cool the flashed light components into a liquid. The vacuum tower is connected to the liquid-phase outlet of the hot hydrogen flash tank. The top of the vacuum tower is connected back to the feedstock oil pipeline, and the bottom is connected to a heavy oil output pipeline.

[0019] In some technical solutions, the hot hydrogen flash tank is provided with a swirl internal part; and / or

[0020] The hot hydrogen flash evaporation unit further includes a second heat exchanger connected in series to the pipeline between the hot hydrogen flash tank and the vacuum tower and a third heat exchanger connected in series to the pipeline of the connection back to the vacuum tower; and / or

[0021] A hydrogen compressor, a fourth heat exchanger, and a heating furnace are sequentially arranged on the hot hydrogen supply pipeline along the hydrogen flow direction; and / or

[0022] The hot hydrogen supply pipeline and the crude oil delivery pipeline are connected to the inlet of the suspended bed reactor through a mixed feed pipeline, and a pipeline mixer for fully mixing hydrogen and crude oil is arranged on the mixed feed pipeline.

[0023] In some technical solutions, the high-pressure separation unit includes a cold high-pressure separator and a stripping tower.

[0024] The cold high-pressure separator is connected to the outlet of the hydrogenation reactor, and a fifth heat exchanger is arranged on the connecting pipeline and an alkali injection port is arranged on the inlet and outlet pipelines of the fifth heat exchanger. The gas phase outlet of the cold high-pressure separator is connected to the hot hydrogen supply pipeline, and the oil phase outlet is connected to the stripping tower. The top of the stripping tower is connected to an acid gas outlet pipe, and the bottom is connected to a product oil output pipeline.

[0025] In some technical schemes, the high-pressure separation unit also includes a hot high-pressure separator connected in series to the pipeline between the hydrogenation reactor and the cold high-pressure separator, the hot high-pressure separator is connected to a hydrogen inlet pipe, and the hydrogen inlet pipe is connected to the hot hydrogen supply pipeline, which is used for hydrogen stripping inside the hot high-pressure separator to remove residual chlorine in the hot high-separation oil, the gas phase outlet of the hot high-pressure separator is connected to the cold high-pressure separator, and the oil phase outlet is connected to the stripping tower.

[0026] In some technical solutions, the high-pressure separation unit further includes an acidic water stripping tower.

[0027] The cold high-pressure separator and the acidic water outlet pipe connected to the stripping tower are both connected to the acidic water stripping tower. The top of the acidic water stripping tower is connected to an acidic gas outlet pipe, and the bottom is connected to a purified water outlet pipe.

[0028] In some technical solutions, the purified water outlet pipe of the acidic water stripping tower is connected back to the water washing section of the cold high-pressure separator;

[0029] And / or, the middle part of the acidic water stripping tower is connected with an ammonia water circulation pipeline, and the ammonia water circulation pipeline is connected with the alkali injection port.

[0030] According to another aspect of the present invention, the present application further provides a method for hydrogenating waste mineral oil, comprising the following steps:

[0031] Centrifuge or mechanically filter the crude oil to remove particle impurities larger than 25 μm;

[0032] The heated circulating hydrogen is fully mixed with the pressurized crude oil and the metal and colloid asphaltene are reacted and coupled to be removed, and then the colloid and asphalt heavy components carried in the crude oil are flashed and separated;

[0033] The gaseous components in the flash product are cooled to the liquid phase and then subjected to a hydrogenation reaction to remove the metals, organic chlorine, and sulfur and nitrogen impurities carried in the feedstock oil.

[0034] The effluent after the hydrogenation reaction is subjected to oil-gas separation to obtain pretreated oil products, or base oil blending components, or fuel oil.

[0035] In some technical solutions, the specific steps for the oil-gas separation of the effluent after the hydrogenation reaction are as follows:

[0036] The effluent after the hydrogenation reaction is heat-exchanged and then subjected to high-temperature separation, and hydrogen stripping is carried out inside to remove the residual chlorine in the high-temperature separated oil. The high-temperature separated gas after separation is heat-exchanged and cooled and then subjected to low-temperature separation. The low-temperature separated gas is recycled as recycle hydrogen. The low-temperature separated oil and the high-temperature separated oil are mixed and then stripped, and the separated acidic water is stripped again. The obtained acidic gas goes to the downstream device for treatment, and the purified water is used to remove the amine in the recycle hydrogen. The ammonia gas is mixed with the purified water and used as recycle ammonia water to neutralize the acidic impurities in the hydrogenation reaction effluent and dissolve them into the acidic water, and the pretreated product is output.

[0037] In some technical solutions, the reaction temperature of the slurry bed reactor is 300 - 400 °C, and the reaction pressure is 5 - 15 MPa; and / or, the flash temperature is 300 - 400 °C, the hydrogenation reaction temperature is 260 - 360 °C, the low-temperature separation temperature is 40 - 60 °C, and the operating pressure of the recycle hydrogen is 5 - 15 MPa; and / or,

[0038] The proportion of the hot oil circulation volume accounts for 0 - 50% of the feedstock oil input volume; and / or,

[0039] The concentration of the recycle ammonia water is between 10 - 30%.

[0040] The present invention adopts the above technical solutions and has at least the following beneficial effects:

[0041] 1. The waste mineral oil hydrotreating system and method proposed in this application use the heat source provided by recycle hydrogen and a small amount of middle distillate recycle oil to mix and heat up the feedstock under hydrogenation conditions, avoiding the problem of easy coking in traditional heating furnace heating and extending the operation cycle of the device;

[0042] 2. The waste mineral oil hydrotreating system and method proposed in this application draw a part of the middle distillate high-temperature feedstock oil from the hot hydrogen flash tank, mix it with recycle hydrogen and use it as the fuel of the heating furnace, and then merge it with the low-temperature feedstock oil, recovering part of the heat, solving the problem of the need for a large amount of recycle hydrogen in the traditional hydrogenation process, reducing energy consumption, and reducing the investment and floor area of the recycle hydrogen system;

[0043] 3. The waste mineral oil hydroprocessing system and method proposed in the present application adopts a hydroprocessing process to remove harmful heavy components such as colloid asphaltene through a suspended bed reactor and a hot hydrogen flash tank; at the same time, demetallization, dechlorination and desulfurization and denitrogenation reactions are carried out in the subsequent hydrogenation reactor to provide high-quality raw materials for subsequent deep hydrogenation treatment, ensuring the long-term operation of the hydrogenation process catalyst;

[0044] 4. The waste mineral oil hydroprocessing system and method proposed in this application effectively removes various impurities in the raw oil through hydrogenation thermal flash evaporation and hydrogenation reaction processes, and does not use chemical agents such as acid, alkali liquid and solvent. The production process is environmentally friendly and does not generate a large amount of organic waste liquid;

[0045] 5. The waste mineral oil hydrotreatment system and method proposed in the present application adopts ammonia water washing, which can not only remove the ammonia salt generated by the reaction, but also neutralize the acidic impurities such as hydrogen sulfide and hydrogen chloride in the reaction effluent into salts and finally dissolve them in acidic water; and the washing ammonia water used is derived from the nitrogen element in the raw oil, and no external supply is required, which solves the problem of setting up the circulating hydrogen desulfurization system and the supporting solvent regeneration device of the traditional hydrogenation system, and reduces the investment and operation cost of the device;

[0046] 6. The waste mineral oil hydrogen treatment system and method proposed in this application sets a final water washing section in the cold high-pressure separator to dissolve the ammonia entrained in the circulating hydrogen in water, thus solving the problem of excessive ammonia content in the circulating hydrogen, resulting in reduced catalyst activity and easy crystallization in the system;

[0047] 7. The waste mineral oil hydrogen treatment system and method proposed in this application is to set up hydrogen stripping in the hot high-pressure separator to remove residual chlorine and H 2 S, etc. can be further removed, reducing the load and energy consumption of subsequent stripping tower removal;

[0048] 8. The waste mineral oil hydrotreatment system and method proposed in the present application organically couples the pretreatment and hydrogenation processes, and performs partial hydrogenation refining while performing pretreatment under hydrogenation conditions, thereby reducing production costs, equipment footprint and investment; the process technology of the present invention can not only produce high-quality pretreated products that can be used as raw materials for deep hydrogenation to produce high-quality base oils, but can also be directly used as low-quality base oil blending components or fuel oil products. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings and their marks required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 This is a schematic structural diagram of the waste mineral oil hydrotreating system described in the embodiments of the present invention.

[0051] The meanings of the reference symbols in the figure are as follows:

[0052] 10 - Filter;

[0053] 21 - Hydrogen compressor, 22 - Heating furnace, 23 - Hot hydrogen flash drum, 24 - Hot oil circulation pump, 25 - Vacuum tower, 26 - Slurry bed reactor;

[0054] 30 - Hydrotreating reactor;

[0055] 41 - Hot high-pressure separator, 42 - Cold high-pressure separator, 43 - Stripping column, 44 - Acid water stripping column. Detailed implementation manners

[0056] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation manners of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings, and other implementation manners can also be obtained.

[0057] To make the drawings concise, only the parts related to the invention are schematically shown in each drawing, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, components with the same structure or function are only schematically shown for one of them, or only one of them is marked. In this document, "one" not only means "only this one", but also means the situation of "more than one".

[0058] It should also be further understood that the term "and / or" used in the specification and appended claims of the present application refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0059] In this document, it should be noted that unless otherwise clearly defined and limited, the terms "install", "connect", and "couple" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0060] In addition, in the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions, and cannot be understood as indicating or implying relative importance.

[0061] In one embodiment, the present invention provides a hydrotreating system for waste mineral oil. Please refer to Figure 1 , the treatment system includes a filtration unit, a hot hydrogen flash evaporation unit, and a hydrogenation reaction unit arranged in sequence along the flow direction of the feedstock oil. Among them, the filtration unit is used to filter out particulate impurities larger than 25 μm in the feedstock oil; the hot hydrogen flash evaporation unit is used to heat the feedstock oil to a preset temperature by hot hydrogen and then carry out reaction coupling and removal of metals and asphaltenes, and then carry out flash evaporation and separate the gum and heavy asphaltene components carried in the feedstock oil; the hydrogenation reaction unit is used to remove metals, organic chlorine, and sulfur and nitrogen impurities in the feedstock oil; the clean oil product after being treated by the above units in sequence is subjected to deep hydrogenation treatment to obtain a higher-quality base oil, or directly used as a base oil blending component and a fuel oil product.

[0062] In this application, the heat source provided by the recycle hydrogen is used to mix and heat the feedstock oil under hydrogenation conditions, avoiding the problem of easy coking in traditional furnace heating and extending the operation cycle of the device; and the flash evaporation and weight removal are carried out by a hydrogenation process to remove harmful heavy components such as asphaltenes, and at the same time, partial hydrofining is carried out subsequently to further remove impurities such as metals, organic chlorine, and sulfur and nitrogen, providing high-quality raw materials for subsequent deep hydrogenation treatment as a pretreatment product.

[0063] In the above embodiment, the filtration unit can adopt mechanical filtration or centrifugal filtration, and can adopt membrane filtration and artificially set the filtration accuracy according to the state of the feedstock oil and the requirements of the produced oil. The device structures used include but are not limited to centrifugal equipment, filter screens, membrane modules, and rectifying distillation devices; the filtration size can be adjusted adaptively according to the composition of the feedstock oil, and is not limited to the 25 μm limit requirement described above in this application. Any appropriate adjustment can be considered to be included within the patent protection scope of this application; during the filtration process, larger particulate matter in the feedstock oil can be removed to reduce the operating load of subsequent impurity removal equipment and maintain the stability of the long-term operation of the system.

[0064] In the above embodiment, the hot hydrogen flash unit includes a suspended bed reactor 26 and a hot hydrogen flash tank 23 connected in sequence, a hot hydrogen supply pipeline and a crude oil delivery pipeline are arranged in parallel upstream of the suspended bed reactor 26, and a catalyst addition pipeline is connected to the crude oil delivery pipeline. The suspended bed reactor 26 is provided with different inlet flow channel distributions to achieve effective dispersion and mixing of the dispersed catalyst, hydrogen and crude oil, thereby realizing the reaction coupling and removal of metal and colloid asphaltene, and the hot hydrogen flash tank 23 is used to separate the colloid and asphalt heavy components carried in the crude oil; specifically, A hydrogen compressor 21, a fourth heat exchanger and a heating furnace 22 are arranged in sequence on the hot hydrogen supply pipeline along the hydrogen flow direction; the hot hydrogen flash tank 23 is provided with a swirl internal component to prevent solid impurities from entering the subsequent hydrogenation reaction with the circulating hydrogen, so that most of the high recovery value fractions in the separated waste mineral oil can be subjected to subsequent hydrogenation dechlorination, demetallization, desulfurization, nitrogen removal and other impurities; preferably, the hot hydrogen supply pipeline and the raw oil delivery pipeline are connected to the inlet of the suspended bed reactor 26 through a mixed feed pipeline, and a pipeline mixer for fully mixing hydrogen and raw oil is arranged on the mixed feed pipeline.

[0065] In a preferred embodiment, a hot oil circulation pipeline is led out from the middle of the hot hydrogen flash tank 23, a hot oil circulation pump 24 is arranged on the hot oil circulation pipeline, and the outlet end of the hot oil circulation pump 24 is connected to the hot hydrogen supply pipeline.

[0066] In this embodiment, a portion of the intermediate distillate high-temperature crude oil is extracted from the hot hydrogen flash tank 23 and mixed with circulating hydrogen as fuel for the heating furnace 22, and then combined with the low-temperature crude oil to recover part of the heat, thereby solving the problem of requiring a large amount of circulating hydrogen in the traditional hydrogenation process, reducing energy consumption, and reducing the investment and footprint of the circulating hydrogen system.

[0067] In a specific embodiment, the hot hydrogen flash unit also includes a first heat exchanger and a vacuum tower 25 located downstream of the hot hydrogen flash tank 23, the first heat exchanger is connected to the gas phase outlet of the hot hydrogen flash tank 23, and is used to cool the light component material flashed out into liquid; the vacuum tower 25 is connected to the liquid phase outlet of the hot hydrogen flash tank 23, the top of the vacuum tower 25 is back-connected to the crude oil delivery pipeline, and the bottom is connected to the heavy oil output pipeline. Preferably, the hot hydrogen flash unit also includes a second heat exchanger connected in series to the pipeline between the hot hydrogen flash tank 23 and the vacuum tower 25, and a third heat exchanger connected in series to the return pipeline of the vacuum tower 25.

[0068] In the above embodiment, the hydrogenation reaction unit includes a hydrogenation reactor 30, and different catalyst grades are loaded in the hydrogenation reactor 30, which can realize the functions of hydrogenation refining such as hydrogenation demetallization, dechlorination, desulfurization and denitrogenation of crude oil, thereby reducing the depth and difficulty of subsequent hydrogenation treatment.

[0069] In some specific embodiments, a high-pressure separation unit is further provided downstream of the above hydrogenation reaction unit for separating oil and gas in the hydrogenation reaction effluent. Generally, the high-pressure separation unit needs to be equipped with a cold high-pressure separator 42 and a stripping column 43. The cold high-pressure separator 42 is connected to the outlet of the hydrogenation reactor 30, and a fifth heat exchanger is arranged on the connecting pipeline and an alkali injection port is arranged on the inlet and outlet pipelines of the fifth heat exchanger. The gas-phase outlet of the cold high-pressure separator 42 is communicated with the hot hydrogen supply pipeline, and the oil-phase outlet is connected to the stripping column 43. The top of the stripping column 43 is communicated with an acidic gas outlet pipe, and the bottom is communicated with a product oil output pipeline.

[0070] In an alternative embodiment, the high-pressure separation unit further includes a hot high-pressure separator 41 connected in series to the pipeline between the hydrogenation reactor 30 and the cold high-pressure separator 42. The hot high-pressure separator 41 is communicated with a hydrogen inlet pipe, and the hydrogen inlet pipe is communicated with the hot hydrogen supply pipeline for hydrogen stripping inside the hot high-pressure separator to remove the residual chlorine in the hot high-pressure separator oil. The gas-phase outlet of the hot high-pressure separator 41 is connected to the cold high-pressure separator 42, and the oil-phase outlet is communicated to the stripping column 43.

[0071] In this embodiment, through the series connection of the cold and hot high-pressure separators and the combined use of the stripping column 43, acidic gases in the hydrogenation reaction effluent can be effectively removed to obtain high-quality output oil products.

[0072] In a preferred embodiment, the high-pressure separation unit further includes an acidic water stripping column 44. The acidic water outlet pipes connected to the cold high-pressure separator 42 and the stripping column 43 are both connected to the acidic water stripping column 44. The top of the acidic water stripping column 44 is communicated with an acidic gas outlet pipe, and the bottom is communicated with a purified water outlet pipe.

[0073] Preferably, the above purified water outlet pipe is connected back to the water washing section of the cold high-pressure separator 42, and the purified water is reused as washing water to absorb ammonia carried in the recycled hydrogen in the cold high-pressure separator gas.

[0074] In this embodiment, in order to prevent ammonia escape, a water washing section is provided in the cold high-pressure separator 42 to dissolve ammonia in the recycled hydrogen in water, solving the problems of excessive ammonia content in the recycled hydrogen, resulting in reduced catalyst activity and easy crystallization in the system.

[0075] Preferably, the middle of the acidic water stripping column 44 is communicated with an ammonia water circulation pipeline, and the ammonia water circulation pipeline is communicated with the alkali injection port.

[0076] In this embodiment, ammonia water is used as the washing medium, which can not only remove the ammonia salt generated by the reaction, but also neutralize the acidic impurities such as hydrogen sulfide and hydrogen chloride in the reaction effluent into salts and finally dissolve them in the acidic water; and the washing ammonia water used is derived from the nitrogen element in the raw oil, and does not require external supply, which solves the setting of the circulating hydrogen desulfurization system and the supporting solvent regeneration device of the traditional hydrogenation system, and reduces the investment and operation costs of the device; and the use of ammonia water for washing solves the high cost of alkali solution used in the traditional reaction gas dechlorination and desulfurization, and solves the problem that the waste liquid generated by the use of alkali solution is difficult to recycle and treat, which pollutes the environment, simplifies the process and reduces costs.

[0077] In the present application, when the product target is lower quality base oil or fuel oil, the present invention can achieve this in one step without subsequent deep hydroprocessing.

[0078] In the present application, waste mineral oil pretreatment technology and hydrogenation technology are organically coupled, and mineral oil pretreatment and hydrogenation refining are simultaneously performed under hydrogen conditions, which simplifies the process compared with the traditional single pretreatment process.

[0079] In another embodiment, the present application further proposes a method for hydrogenating waste mineral oil, comprising the following steps:

[0080] Centrifuge or mechanically filter the crude oil to remove particle impurities larger than 25 μm;

[0081] The heated circulating hydrogen is fully mixed with the pressurized crude oil and the metal and colloid asphaltene are reacted and coupled to be removed, and then the colloid and asphalt heavy components carried in the crude oil are flashed and separated;

[0082] The gas phase components in the flash product are cooled to liquid phase and then subjected to hydrogenation reaction to remove metal, organic chlorine and sulfur and nitrogen impurities carried in the crude oil;

[0083] The effluent after the hydrogenation reaction is subjected to oil and gas separation to obtain a pretreated oil product or a base oil blending component or a fuel oil.

[0084] In some specific embodiments, the specific steps of separating oil and gas from the effluent after the hydrogenation reaction are as follows: subjecting the effluent after the hydrogenation reaction to heat exchange and then subjecting it to hot high separation, and removing residual chlorine in the hot high oil fraction by internally arranging hydrogen stripping, subjecting the separated hot high fraction gas to cold high separation after heat exchange and cooling, and reusing the cold high fraction gas as circulating hydrogen, stripping the cold high fraction oil after mixing with the hot high fraction oil, and stripping the separated acidic water again, and sending the obtained acidic gas to a downstream device for treatment, and using purified water to remove amines from the circulating hydrogen, and using ammonia mixed with purified water as circulating ammonia water to neutralize acidic impurities in the hydrogenation reaction effluent and dissolve them in the acidic water, and outputting the pretreated product.

[0085] In this embodiment, the heat source provided by recycle hydrogen and a small amount of middle distillate recycle oil is used to mix and heat up the raw materials under the condition of hydrogen, avoiding the problem of easy coking in traditional furnace heating and prolonging the operation cycle of the unit;

[0086] This embodiment adopts a hydrogenation process to remove heavy components such as harmful resins and asphaltenes through a suspension bed reactor and a hot hydrogen flash tank; at the same time, in subsequent hydrogenation reactions, reactions such as demetallization, dechlorination, and desulfurization and denitrification are carried out to provide high-quality raw materials for subsequent deep hydrogenation treatment and ensure the long-term operation of the hydrogenation process catalyst.

[0087] In another embodiment, on the basis of the above-mentioned waste mineral oil hydrogen treatment system solution, a treatment method thereof is further provided, which is specifically described as follows:

[0088] The raw material oil is filtered by a filter 10 to remove particulate impurities larger than 25 μm in the raw material, then mixed with a dispersive catalyst and pressurized by a raw material pump. After the recycle hydrogen is mixed with the high-temperature raw material oil drawn from the hot hydrogen flash tank 23, it is heated by a recycle hydrogen heating furnace. The heated hydrogen and raw material oil enter the suspension bed reactor 26 through different flow channels. The reaction effluent at the top of the suspension bed enters the hot hydrogen flash tank 23 for pretreatment to remove slag and perform gas-liquid separation. The oil phase rich in resins, asphaltene heavy components and other impurities coming out from the bottom of the hot hydrogen flash tank 23 enters the vacuum tower 25. The gas phase at the top of the hot hydrogen flash tank exchanges heat through a heat exchanger and then enters the reactor for demetallization, dechlorination, desulfurization and denitrification reactions; the reaction effluent after hydrogenation exchanges heat through a heat exchanger and then enters the hot high-pressure separator 41 for oil-gas separation. The hot high-pressure separator 41 is provided with hydrogen stripping to remove the residual chlorine in the hot high-pressure oil. The hot high-pressure oil at the bottom of the hot high-pressure separator 41 enters the stripping tower 43; the hot high-pressure gas at the top is cooled by heat exchange and then enters the cold high-pressure separator 42. The gas phase of the cold high-pressure separator 42 is boosted by a recycle hydrogen compressor and then used as recycle hydrogen to enter the recycle hydrogen heating furnace for temperature rise after heat exchange; the cold high-pressure oil at the bottom of the cold high-pressure separator 42 exchanges heat and then is mixed with the hot high-pressure oil and enters the stripping tower 43; in order to remove acidic impurities such as hydrogen chloride in the reaction effluent and prevent crystallization salts from precipitating and blocking the pipeline at low-temperature positions, ammonia water is injected in front of the cold high-pressure separator 42 and the pipeline before it to neutralize acidic substances such as HCL and dissolve crystalline salts. In order to prevent the ammonia in the recycle hydrogen from affecting the activity of the reaction catalyst and crystallizing in the system pipeline and equipment, a water washing section is provided in the cold high-pressure separator 42 to remove the ammonia in the recycle hydrogen.

[0089] The light components at the top of the vacuum tower are sent to the raw material oil line for recovery after heat exchange and cooling; the heavy oil product at the bottom of the vacuum tower is taken out of the unit after heat exchange and cooling as a heavy product.

[0090] The hot high-pressure oil and the cold high-pressure oil are combined and enter the stripping tower 43. The gas at the top of the tower is acidic gas and is sent to a downstream unit for treatment; the bottom oil of the stripping tower is cooled after recovering heat through a heat exchanger and used as a pretreatment product.

[0091] The acidic water generated at the top of the stripping tower and the acidic water generated by the cold high-pressure separator 42 are mixed and then sent to the acidic water stripping tower 44 for separation. The acidic gas at the top of the tower is sent to downstream units for treatment. Ammonia is withdrawn from the middle of the acidic water stripping tower. After being purified water, it is used as recycled ammonia water, and the purified water at the bottom of the tower is reused as the washing water injection for the cold high-pressure separator 42.

[0092] When the plant scale is small, in order to reduce investment, this technical solution can only adopt the cold high-pressure separation process, that is, the hot high-pressure separation tank is cancelled, and the reaction effluent is directly cooled to the cold high-pressure separator 42 in its entirety, and the ammonia injection position remains unchanged.

[0093] Among them, the parameter control of each process is as follows:

[0094] The temperature of the slurry bed reactor is 340 °C, which can be adjusted between 300 - 400 °C according to the raw material properties and product requirements; the addition amount of the slurry bed catalyst is 0.1 - 2%, which is adjusted according to different raw material properties and product requirements;

[0095] The temperature of the hydroflash drum is 350 °C, and it is recommended to be 300 - 400 °C and adjusted according to the raw material properties;

[0096] The reactor temperature is 300 °C, and the recommended operating temperature is 260 - 360, which is adjusted according to the initial and final stages of operation and the catalyst grading scheme;

[0097] The temperature of the cold high-pressure separator 42 is 50 °C, and the recommended operating temperature is 40 - 60 °C;

[0098] The operating pressure of the recycle hydrogen system is 6.0 MPaG, and it is recommended to be 5.0 - 10.0 MPa, which is adjusted according to the raw material properties and the catalyst reaction requirements;

[0099] The circulation rate of the hot oil circulation pump 24 is 20% of the feed, and the actual circulation rate can be directly selected between 0 - 50% according to the plant scale, reactor temperature requirements and the configuration of the recycle hydrogen compressor;

[0100] According to the properties of typical waste mineral oils, the heavy oil yield of the present invention is about 7 - 8%, and the recommended yield is 5 - 15% according to product requirements;

[0101] According to the properties of typical waste mineral oils, the yield of the pretreatment product is about 87%, and the actual yield is recommended to be between 80 - 90% according to the raw material properties and different final product requirements;

[0102] The concentration of the recycled ammonia water is 20%, and it can be selected in the range of 10 - 30% according to the raw material characteristics and the net washing and neutralization effect.

[0103] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the appended claims.

Claims

1. A waste mineral oil hydrotreatment system, characterized in that: It includes a filtering unit, a hot hydrogen flash unit, a hydrogenation reaction unit and a high-pressure separation unit which are arranged in sequence along the flow direction of the crude oil. The filtering unit is used to filter out particulate impurities larger than 25 μm in the raw oil; The hot hydrogen flash unit comprises a suspended bed reactor and a hot hydrogen flash tank connected in sequence, a hot hydrogen supply pipeline and a crude oil delivery pipeline are arranged in parallel upstream of the suspended bed reactor, a hydrogen compressor, a fourth heat exchanger and a heating furnace are arranged in sequence on the hot hydrogen supply pipeline along the hydrogen flow direction, a catalyst addition pipeline is connected to the crude oil delivery pipeline, and the suspended bed reactor achieves effective dispersion and mixing of the dispersed catalyst, hydrogen and crude oil by setting different inlet flow channel distributions, thereby realizing the reaction coupling and removal of metal and colloid asphaltene; the hot hydrogen flash tank is used to separate the colloid and asphalt heavy components carried in the crude oil, a hot oil circulation pipeline is led out from the middle of the hot hydrogen flash tank, and the hot oil circulation pipeline is connected back to the hot hydrogen supply pipeline; The hot hydrogen flash unit also includes a first heat exchanger and a vacuum tower arranged downstream of the hot hydrogen flash tank, wherein the first heat exchanger is connected to the gas phase outlet of the hot hydrogen flash tank and is used to cool the light component material flashed out into liquid; the vacuum tower is connected to the liquid phase outlet of the hot hydrogen flash tank, the top of the vacuum tower is back-connected to the crude oil delivery pipeline, and the bottom is connected to the heavy oil output pipeline; The hydrogenation reaction unit is used to remove metal, organic chlorine and sulfur and nitrogen impurities in the crude oil, and includes a hydrogenation reactor, in which a hydrogenation catalyst is installed; The high-pressure separation unit is used for oil and gas separation in the hydrogenation reaction effluent; The clean oil products processed by the above units are used as pre-treated products for deep hydrogenation treatment to obtain higher quality base oil, or directly used as base oil blending components and fuel oil products.

2. The waste mineral oil hydrotreatment system according to claim 1, characterized in that: The hot hydrogen flash tank is provided with swirl internals; and / or, The hot hydrogen flash unit further includes a second heat exchanger connected in series to the pipeline between the hot hydrogen flash tank and the vacuum tower and a third heat exchanger connected in series to the return pipeline of the vacuum tower; and / or, The hot hydrogen supply pipeline and the crude oil delivery pipeline are connected to the inlet of the suspended bed reactor through a mixed feed pipeline, and a pipeline mixer for fully mixing hydrogen and crude oil is arranged on the mixed feed pipeline.

3. The waste mineral oil hydrotreatment system according to claim 1, characterized in that: The high-pressure separation unit includes a cold high-pressure separator and a stripping tower. The cold high-pressure separator is connected to the outlet of the hydrogenation reactor, and a fifth heat exchanger is arranged on the connecting pipeline and an alkali injection port is arranged on the inlet and outlet pipelines of the fifth heat exchanger. The gas phase outlet of the cold high-pressure separator is connected to the hot hydrogen supply pipeline, and the oil phase outlet is connected to the stripping tower. The top of the stripping tower is connected to an acid gas outlet pipe, and the bottom is connected to a product oil output pipeline.

4. The waste mineral oil hydrotreatment system according to claim 3, characterized in that: The high-pressure separation unit also includes a hot high-pressure separator connected in series to the pipeline between the hydrogenation reactor and the cold high-pressure separator, the hot high-pressure separator is connected to a hydrogen inlet pipe, the hydrogen inlet pipe is connected to the hot hydrogen supply pipeline, and is used for hydrogen stripping inside the hot high-pressure separator to remove residual chlorine in the hot high-separation oil, the gas phase outlet of the hot high-pressure separator is connected to the cold high-pressure separator, and the oil phase outlet is connected to the stripping tower.

5. The waste mineral oil hydrotreatment system according to claim 3 or 4, characterized in that: The high pressure separation unit also includes a sour water stripping tower, The cold high-pressure separator and the acidic water outlet pipe connected to the stripping tower are both connected to the acidic water stripping tower. The top of the acidic water stripping tower is connected to an acidic gas outlet pipe, and the bottom is connected to a purified water outlet pipe.

6. The waste mineral oil hydrotreatment system according to claim 5, characterized in that: The purified water outlet pipe of the acidic water stripping tower is connected back to the water washing section of the cold high-pressure separator; And / or, the middle part of the acidic water stripping tower is connected with an ammonia water circulation pipeline, and the ammonia water circulation pipeline is connected with the alkali injection port.

7. A method for hydrogenating waste mineral oil, characterized in that: A waste mineral oil hydrotreatment system suitable for any one of claims 1 to 6, comprising the following steps: Centrifuge or mechanically filter the crude oil to remove particle impurities larger than 25 μm; The heated circulating hydrogen is fully mixed with the pressurized crude oil and the metal and colloid asphaltene are reacted and coupled to be removed, and then the colloid and asphalt heavy components carried in the crude oil are flashed and separated; The gas phase components in the flash product are cooled to liquid phase and then subjected to hydrogenation reaction to remove metal, organic chlorine and sulfur and nitrogen impurities carried in the crude oil; The effluent after the hydrogenation reaction is subjected to oil and gas separation to obtain a pretreated oil product or a base oil blending component or a fuel oil.

8. The method for hydrotreating waste mineral oil according to claim 7, characterized in that: The specific steps of separating oil and gas from the effluent after the hydrogenation reaction are as follows: The effluent after the hydrogenation reaction is subjected to heat exchange and then hot high separation, and the residual chlorine in the hot high oil fraction is removed by internally arranging hydrogen stripping. The hot high fraction gas after separation is subjected to heat exchange and cooling and then cold high separation is performed. The cold high fraction gas is reused as circulating hydrogen, and the cold high fraction oil is mixed with the hot high fraction oil and then stripped, and the separated acidic water is stripped again. The obtained acidic gas is sent to the downstream device for treatment, and the purified water is used to remove ammonia in the circulating hydrogen. The ammonia mixed with the purified water is used as circulating ammonia water to neutralize the acidic impurities in the hydrogenation reaction effluent and dissolve them in the acidic water, and output the pretreated product.

9. The method for hydrotreating waste mineral oil according to claim 8, characterized in that: The reaction temperature of the suspended bed reactor is 300-400° C. and the reaction pressure is 5-15 MPa; and / or, The flash temperature is 300-400°C, the hydrogenation reaction temperature is 260-360°C, the cold high separation temperature is 40-60°C, and the operating pressure of the circulating hydrogen is 5-15MPa; and / or, The hot oil circulation volume accounts for 0-50% of the crude oil input volume; and / or, The concentration of circulating ammonia water is between 10-30%.

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