Method for producing dewaxed oil and wax products from heavy hydrocarbon oil

Abstract

The invention relates to a method for producing dewaxed oil and wax products from heavy hydrocarbon oil, which comprises the following steps: (1) under the dewaxing condition, mixing a diluting solvent with a heavy hydrocarbon oil raw material, carrying out solvent dewaxing, cooling to a filtering temperature, and carrying out solid-liquid separation on a wax-containing solution to obtain dewaxed filtrate and cerate, the content of the diluting solvent in the cerate being 30-80wt%; the diluting solvent is C3-C6 aliphatic ketone and / or C6-C8 aromatic hydrocarbon; (2) removing the diluting solvent in the filtrate to obtain dewaxed oil with a reduced pour point; (3) introducing the cerate into a sweating system, and heating and sweating to obtain deoiled cerate; and (4) introducing the deoiled cerate into a de-oiling system, and removing the diluting solvent in the deoiled cerate to obtain a wax product. According to the method provided by the invention, the wax paste which is obtained by solvent dewaxing and contains the diluting solvent is directly sweated and deoiled, and dewaxed oil and a wax product are obtained at the same time. The process of cooling and solidifying after wax melting is omitted by adopting cerate sweating containing a diluting solvent, the sweating temperature lower than that of conventional sweating is adopted, and the heating amount is saved.

Description

Technical Field

[0001] The invention belongs to the field of petroleum wax production, and in particular relates to a method for producing paraffin wax by adopting a sweating deoiling method to reduce the oil content in dewaxed wax paste. Background Art

[0002] Paraffin is a general term for wax products obtained after crude oil is processed through various petroleum processing procedures, including liquid paraffin, soap wax, semi-refined paraffin, fully refined paraffin and microcrystalline wax. It is mainly composed of normal alkanes, a small amount of isoalkanes and cycloalkanes and other hydrocarbons. It is an important chemical raw material and can be widely used in rubber, plastics, fine chemicals, daily chemicals and other fields, with stable market demand.

[0003] Dewaxing is the process of separating high-freezing-point components and low-freezing-point components from waxy oil components under dewaxing conditions. The low-freezing-point components have the characteristics of low n-alkanes content and good low-temperature fluidity, and can be used as products or production raw materials with low-temperature fluidity requirements, such as lubricating oil base oil production raw materials. The high-freezing-point components obtained by dewaxing have the characteristics of high n-alkanes content and remain solid at higher temperatures, but they also contain oil and low-carbon n-alkanes and isoalkanes and other components, which affect the performance of paraffin wax, so they need to be removed. This process is called wax deoiling. The main methods for producing dewaxed oil and paraffin wax include cold pressing dewaxing sweating deoiling process, solvent dewaxing and deoiling process, urea dewaxing process, molecular sieve dewaxing process and spray deoiling process.

[0004] The solvent dewaxing and deoiling process uses vacuum distillate oil or light deasphalted oil as raw material, a mixture of butanone and toluene as solvent, and uses the different solubility of oil and wax in the raw oil in the mixed solvent to separate the two components under dewaxing conditions to obtain oil dissolved in the solvent and dewaxed wax paste that is not dissolved in the oil liquid. The mixture of oil and solvent is separated to obtain dewaxed oil and solvent. Further, the wax and soluble components in the wax paste have different solubilities in the mixed solvent. The wax and other components are separated under deoiling conditions to obtain soluble components dissolved in the solvent and deoiled wax paste that is not dissolved in the oil liquid. The mixture of soluble components and solvent is separated to obtain wax oil, and the deoiled wax paste is separated from the solvent to obtain deoiled wax, which can be refined to obtain wax products. Solvent dewaxing has the characteristics of continuous production process, high wax yield and low wax oil content, but the solvent dewaxing and deoiling agent oil ratio is between 6 and 10, the solvent recovery evaporation energy consumption is large, and the comprehensive energy consumption is 60 to 80 kgoe / t, which is a major energy consumer in petroleum refining.

[0005] The cold pressing dewaxing and sweating deoiling process uses vacuum distillate oil as raw material, and utilizes the different solidification temperatures of oil and wax in the raw oil to separate oil and crude wax under cold pressing conditions. Crude wax contains hydrocarbons such as alkanes, cycloalkanes with side chains, and aromatics with side chains, and their melting temperatures vary according to the length of the carbon chain, the degree of isomerization, and the ring structure and number. Within the same molecular weight range, the higher the degree of normalization of the alkanes, the higher the melting point. As the degree of isomerization increases, the melting point decreases, and the melting point also decreases after the cyclic hydrocarbons are connected. Sweating is to use the difference in melting points of different hydrocarbons in crude wax to separate them at different temperatures, thereby obtaining products with different hydrocarbon structures, and further refining to obtain wax products with different melting points. Cold pressing dewaxing and sweating deoiling has the characteristics of intermittent production process, no need to use organic solvents, and low energy consumption. In the conventional sweating and deoiling process, as the sweating temperature gradually increases, the low melting point components in the material melt into liquid and flow out through the pores between the wax crystals. In order to meet the separation accuracy requirements, the method of extending the sweating time and increasing the sweating termination temperature to close to the wax melting point is generally adopted to obtain products that meet the product quality. However, there are problems such as low production efficiency, high temperature energy consumption, and low deoiling wax yield.

[0006] CN105733679A discloses a method for producing soap wax and paraffin wax by sweating. This method, based on the common sweating deoiling process, adds a low-boiling point liquid to the raw oil, and uses airflow to carry liquid oil through the wax layer during the temperature-raising sweating process to force the separation of wax and oil. However, there are problems such as compression of the wax layer under pressure, and the smaller channel of oil in the wax, which is not conducive to the separation of oil and wax. CN114437826A discloses a method for producing phase-change energy storage wax. This method adds a light solvent to the Fischer-Tropsch narrow fraction, which is conducive to the discharge of isomeric hydrocarbons and light components, and improves the sweating efficiency and sweating effect. However, there are problems such as low solvent solubility and insufficient sweat discharge. In order to solve the problem of dense wax layer and insufficient sweat discharge in the sweating process in the prior art, the present invention proposes an improved method for producing paraffin wax by sweating. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for producing dewaxed oil and wax products from heavy hydrocarbon oil, thereby reducing the oil content in the wax products and reducing energy consumption.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a method for producing dewaxed oil and deoiled wax products from heavy hydrocarbon oil, comprising: (1) under dewaxing conditions, mixing a diluent solvent with a heavy hydrocarbon oil feedstock and performing solvent dewaxing, cooling to a filtration temperature, and performing solid-liquid separation on the wax-containing solution to obtain a dewaxed filtrate and a wax paste, wherein the content of the diluent in the wax paste is 30wt%-80wt%; the diluent is C3-C6 fatty ketone and / or C6-C8 aromatic hydrocarbon; (2) introducing the dewaxed filtrate into a deagent system, removing the diluent in the filtrate to obtain a dewaxed oil with a reduced pour point; (3) introducing the wax paste into a sweating system to heat and sweat to obtain a deoiled wax paste; (4) introducing the deoiled wax paste into a deagent system, removing the diluent in the deoiled wax paste to obtain a wax product.

[0009] Compared with the prior art, the method for producing dewaxed oil and wax products from heavy hydrocarbon oil provided by the present invention has the following beneficial effects:

[0010] The method provided by the present invention directly sweats and deoils the wax paste containing a diluent solvent obtained by solvent dewaxing, and simultaneously obtains dewaxed oil and wax products with reduced pour point. A diluent solvent is added to a heavy hydrocarbon oil raw material as a crystallization improving material to reduce the viscosity of the solution between wax crystals, and helps wax crystal nucleation and growth during the wax crystallization process to form large crystalline particles. The separated wax paste is a loose wax cake formed by the accumulation of wax crystals, with large intercrystalline spaces and many channels. The diluent solvent wrapped in the wax crystals during the wax crystallization process acts as an oil dissolving agent during the sweating process, which can effectively reduce the viscosity of sweat and facilitate sweat discharge. The use of a wax paste containing a diluent solvent for sweating saves the process of cooling and solidifying the wax after melting, and reduces the sweating operation steps. A sweating temperature lower than conventional sweating can be used, for example, the melting point of the wax product produced is 55-65°C, and the sweating termination temperature is 13-20°C lower than the melting point of the wax product, saving energy consumption. The diluent can be recycled after recovery, and no oil-containing waste is generated.

[0011] Other features and advantages of the present invention are described in detail in the following detailed description. DETAILED DESCRIPTION

[0012] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0013] The present invention provides a method for producing dewaxed oil and wax products from heavy hydrocarbon oil, comprising: (1) under dewaxing conditions, mixing a diluting solvent with a heavy hydrocarbon oil raw material and performing solvent dewaxing, cooling to a filtration temperature, and performing solid-liquid separation on the wax-containing solution to obtain a dewaxed filtrate and a wax paste, wherein the content of the diluting solvent in the wax paste is 30wt%-80wt%; the diluent is C3-C6 fatty ketone and / or C6-C8 aromatic hydrocarbon; (2) introducing the dewaxed filtrate into a deagent removal system, removing the diluting solvent in the filtrate to obtain dewaxed oil with a reduced pour point; (3) introducing the wax paste into a sweating system to heat and sweat, to obtain a deoiled wax paste; (4) introducing the deoiled wax paste into a deagent removal system, removing the diluting solvent in the deoiled wax paste to obtain a wax product.

[0014] In the present invention, the heavy hydrocarbon oil raw material has a distillation range of 350°C to 500°C, a freezing point of >25°C, and is selected from vacuum distillate oil or solvent refined oil.

[0015] Optionally, the dilution solvent is selected from one or more of acetone, butanone, benzene and toluene;

[0016] Preferably, the dilution solvent is a mixture of butanone and toluene, wherein the volume content of butanone is 45v% to 70v%; preferably, the volume content of butanone is 50v% to 65v%.

[0017] Optionally, in step (1), the diluent solvent is added to the heavy hydrocarbon oil once or several times, and a mixed oil solution is obtained after mixing. The mixed oil solution is cooled to the filtration temperature at a rate of 0.5 to 4°C / min, and the high-freezing-point components are separated out at low temperature. After solid-liquid separation, a dewaxing filtrate and wax paste are obtained; the temperature of the mixed oil solution when the diluent solvent is added for the first time is 25 to 70°C, the filtration temperature is -30 to -5°C, and the temperature of the wax paste is -30 to -5°C;

[0018] Preferably, the temperature of the mixed oil solution to which the dilution solvent is added for the first time is 30 to 65°C.

[0019] Preferably, the cooling rate is 1-3°C / min

[0020] Preferably, the filtration temperature is -25 to -10°C.

[0021] Optionally, in step (1), the mass ratio of the dilution solvent to the heavy hydrocarbon oil feedstock is 1 to 4.5:1;

[0022] Preferably, the mass ratio of the dilution solvent to the heavy hydrocarbon oil feedstock is 1.5 to 4:1.

[0023] Optionally, the solvent dewaxing step is carried out in a crystallization stirring kettle, and the wall scraping stirring speed of the crystallization stirring kettle is 20 to 300 rpm during the cooling process of the mixed oil solution of the dilution solvent and the heavy hydrocarbon oil feedstock;

[0024] Preferably, the wall scraping stirring speed of the crystallization stirring kettle is 30 to 200 rpm.

[0025] In step (2), the diluent in the dewaxed filtrate is removed by evaporation.

[0026] In the method provided by the present invention, the oil content in the wax paste obtained in step (1) is not less than 4%.

[0027] Optionally, in step (3), the wax paste is heated from the sweating start temperature to the sweating end temperature in the sweating dish and then kept at a constant temperature for 2 to 3 hours, the sweating start temperature is 5°C higher than the temperature of the wax paste, the heating rate is 0.5 to 4°C / h, and the sweating end temperature is 10 to 25°C lower than the melting point of the wax product; after sweating, a deoiled wax paste is obtained; the deoiled wax paste has an oil content of 1.0-1.9wt%, and after further removing the solvent from the deoiled wax paste, a wax product with a melting point of 50 to 70°C is obtained.

[0028] When the heavy hydrocarbon oil feedstock is used to produce a wax product with a melting point of 50-70°C, the sweating end temperature is 10-25°C lower than the melting point of the wax product, preferably 16°C-20°C lower.

[0029] Preferably, the heating rate is 1-3°C / h.

[0030] Optionally, the deoiled wax paste obtained by sweating has a diluent content of 1-6%.

[0031] Preferably, the sweating termination temperature is 13-20°C lower than the melting point of the deoiled wax paste, the oil content in the obtained deoiled wax paste is 1.1-1.6wt%, and after further removing the dilution solvent, a wax product with a melting point of 55-65°C is obtained.

[0032] When the heavy hydrocarbon oil feedstock is used to produce a wax product having a melting point of 55-65°C, the sweating end temperature is 13-20°C lower than the melting point of the wax product, preferably 14-16°C lower.

[0033] The method provided by the present invention comprises the following steps: adding a diluting solvent to a heavy oil raw material, uniformly mixing the oil liquid with the diluent at a dilution temperature to form a solution of the raw oil and the diluent, cooling the solution to a filtering and separation temperature under a cooling condition, separating the wax-containing solution to obtain a dewaxed filtrate and a wax paste, and removing the solvent from the dewaxed filtrate to obtain a dewaxed oil. The wax paste is introduced into a sweating system, heated and sweated, and the wax liquid obtained at different sweating temperatures is collected. After removing the solvent, products with different oil contents can be obtained. During the dewaxing process, adding a diluting solvent to the raw oil reduces the viscosity of the dewaxed oil liquid, which is conducive to the precipitated wax crystals adhering to and growing around the crystal nucleus to form large wax crystals. During the process of cooling and cooling the dewaxed oil liquid and the refrigerant, the dewaxed oil liquid is continuously stirred, and the wax crystals formed on the cold wall are scraped off to enter the oil liquid, and the wax crystals are partially dissolved and then attached to the crystal nucleus to grow. This is repeated to form wax crystals with low oil content and high strength. After filtering and removing the oil liquid, a loose wax cake layer is formed, and the space between the wax crystal layers is large, which is conducive to the flow of sweat during the sweating process, thereby achieving the purpose of sweating to reduce the oil content in the wax.

[0034] In the method provided by the present invention, in step (1), the dilution temperature is the temperature at which the first added diluent is evenly mixed with the raw oil liquid to obtain a solution containing the diluent. The temperature at which the first diluent is added to the raw oil liquid is 25°C to 70°C, preferably 30°C to 65°C.

[0035] Optionally, the dilution solvent may be added once or in multiple times, preferably in 2 or 3 times.

[0036] The solvent dewaxing device is used for solvent dewaxing, preferably a crystallization stirring kettle is used, and the wall scraping stirring means that the dewaxed oil liquid is continuously scraped off during the cooling and crystallization process of the crystallization stirring kettle, and the oil solution is contacted with the refrigerant to exchange cold, and the condensed wax crystals are precipitated on the cold wall. The fallen wax crystals are redissolved and recrystallized in the oil solution, and the cycle is repeated to form wax crystals with low oil content and large particles. The speed of scraping the wall stirring the oil solution during the cooling and cooling process of the oil solution added with the diluent and the refrigerant is 20 to 300 rpm, preferably 30 to 200 rpm.

[0037] In step (1), optionally, the wax-containing oil liquid is solid-liquid separated to obtain a dewaxed filtrate and a wax paste. The solid-liquid separation can be carried out by conventional solid-liquid separation methods in the art, such as natural sedimentation and filtration separation, and preferably by filtration separation. The separation method can adopt the existing technology and will not be described here. The wax paste is the unfiltered material obtained after the solid-liquid separation of the wax-containing oil solution at the filtration temperature, the mass fraction of the solvent in the wax paste is 30wt% to 80wt%, preferably 35wt% to 75wt%, and the temperature of the wax paste is -30 to -10°C.

[0038] In the method provided by the present invention, in step (2), the dewaxed filtrate is introduced into a desolventizing system to remove the diluent solvent in the filtrate to obtain dewaxed oil. The solvent removal adopts the existing technology, and the diluent solvent in the filtrate can be removed by evaporation and vaporization.

[0039] In the method provided by the present invention, in step (3), the wax paste obtained in step (1) is introduced into a sweating system, and the temperature is increased under controlled conditions to sweat, and the heating rate is 0.5 to 4°C / h, preferably 1 to 3°C / h.

[0040] In the method of the present invention, the temperature rise rate of solvent dewaxing and wax layer sweating can be controlled by air bath, water bath and oil bath, etc., and a jacket, coil and the like can be set to allow the heat medium to exchange heat with the material. When cooling, the heat exchange and cooling are prior arts, and technicians can perform them according to the temperature control requirements, which will not be described in detail here.

[0041] The present invention also comprises step (4), removing the diluting solvent from the deoiled wax paste obtained by sweating to obtain a wax product with low oil content.

[0042] The method for removing the solvent from the dewaxed filtrate and the deoiled wax paste is well known in the art. For example, the logistics are respectively sent to a solvent recovery tower to remove the solvent to obtain dewaxed oil and wax products, and the recovered diluent is recycled.

[0043] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0044] The present invention will be described in detail below through examples.

[0045] The calculation formula of the solvent content in the wax paste is: solvent content = ((wax paste mass - wax paste mass after solvent removal) ÷ ​​wax paste mass) × 100%;

[0046] The formula for calculating the mass yield of dewaxed oil is: mass yield of dewaxed oil = (mass of dewaxed oil ÷ mass of dewaxed raw oil) × 100%;

[0047] The mass yield of the wax product is calculated as follows: mass yield of the wax product = (mass of the wax product / mass of the dewaxed raw oil) × 100%.

[0048] In the embodiment:

[0049] Heavy hydrocarbon oil feedstock A and heavy hydrocarbon oil feedstock B were obtained from Maoming Branch of Sinopec Co., Ltd. Their properties are shown in Table 1, and their analysis methods are shown in Table 2.

[0050] Table 1

[0051] project Heavy hydrocarbon oil feedstock A Heavy hydrocarbon oil feedstock B <![CDATA[Kinematic viscosity (100 °C) / (mm 2 / s)]]> 9.364 4.588 Freezing point / ℃ / 27 Pour point / ℃ 45 / Distillation range / ℃ 5 / ％ 437 371 50 / ％ 493 419 95％ 542 455

[0052] Example 1

[0053] (1) The dilution solvent is a mixture of butanone and toluene, and the volume fraction of butanone is 50% by volume.

[0054] The dilution solvent was added to the heavy hydrocarbon oil feedstock A twice. The first addition temperature of the dilution solvent was 65°C and the dilution ratio was 1. The second addition temperature of the dilution solvent was 30°C and the dilution ratio was 3. The mass ratio of the dilution solvent to the heavy hydrocarbon oil feedstock was 4:1.

[0055] The solvent dewaxing device adopts a jacketed crystallization stirring kettle, the solution is cooled from the first diluent addition temperature to the filtration temperature at a cooling rate of 1°C / min, the wall scraping stirring speed is 200 rpm, the temperature is cooled to the filtration temperature of -10°C, the filter cake is filtered and separated at the filtration temperature and rinsed with a rinse agent to obtain a filtrate and wax paste, the rinse agent is a mixture of butanone and toluene, the volume fraction of butanone is 50v%, the mass ratio of the rinse agent to the heavy hydrocarbon oil raw material A is 0.5, and the rinse temperature is -10°C. The solvent content in the wax paste is 40wt%, and the oil content is 7.9wt%.

[0056] (2) After removing the solvent from the filtrate, dewaxed oil was obtained, which was weighed and calculated to have a mass yield of 64.8 wt %.

[0057] (3) The temperature of the wax paste used for sweating is -10°C. The wax paste is placed in a sweating dish. The starting temperature of sweating is -5°C, the heating rate is 1°C / h, the ending temperature of sweating is 45°C, and the constant temperature time is 2h. After the sweating is completed, the melted oil is filtered out to obtain the deoiled wax paste. The melting temperature of the deoiled wax paste is 48°C. (4) The diluent in the deoiled wax paste is removed to obtain a wax product. The mass yield of the wax product is 15.9%, the melting point is 64.3°C, the oil content is 1.55%, and the kinematic viscosity at 100°C is 5.929mm 2 / s, its oil content and melting point can meet the technical requirements of melting point and oil content of No. 64 semi-refined wax.

[0058] Comparative Example 1

[0059] Comparative Example 1 adopts the conventional solvent dewaxing and sweating method for removing oil from wax, the heavy hydrocarbon oil feedstock A is the same as that of Example 1, and step (1) is the same as that of Example 1.

[0060] (2) removing the diluting solvent from the obtained wax paste to obtain a desolventized wax paste, wherein the mass yield of the wax paste is 35.2 wt %, the oil content in the wax paste is 7.9 wt %, and the wax paste does not contain solvent.

[0061] (3) Add 5% butanone to the dewaxed wax paste, melt it at 60°C and use it as a sweating raw material; put the sweating raw material into a sweating tank and heat it to melt, then cool it down to 35°C at a rate of 1.5°C / h. After the wax paste is cold treated for 5 hours, it starts to sweat, with a starting temperature of 35°C, a heating rate of 1°C / h, a sweating end temperature of 62°C, and a constant temperature time of 2 hours. After the sweating is completed, the deoiled wax paste is obtained.

[0062] (4) Remove butanone from the deoiled wax paste to obtain a wax product. The mass yield of the wax product is 14.8%, the melting point is 63.8°C, the oil content is 2.59%, and the kinematic viscosity at 100°C is 5.283 mm 2 / s, when the wax melting points are basically the same, its oil content cannot meet the technical requirements for oil content of No. 62 semi-refined wax.

[0063] Example 2

[0064] (1) A mixture of butanone and toluene is used as a dilution solvent, wherein the volume fraction of butanone is 65%, and the mass ratio of the dilution solvent to the raw material oil is 1.5:1. In a crystallization stirring kettle, the dilution solvent is added to the heavy hydrocarbon oil raw material B twice, the first dilution solvent addition temperature is 30°C, the dilution ratio is 0.5, the second dilution solvent addition temperature is 0°C, the dilution ratio is 1, the filtration temperature is -23°C, the cooling rate of the solution from the first dilution solvent addition temperature to the filtration temperature is 3°C / min, the wall scraping stirring speed of the crystallization stirring kettle is 30 rpm, and the filtrate and wax paste are obtained by filtration and separation at the filtration temperature, respectively, the flushing agent is a mixture of butanone and toluene, the volume fraction of butanone is 65v%, the mass ratio of the flushing agent to the raw material oil is 0.5, and the flushing temperature is -23°C. The solvent content in the obtained wax paste is 75wt%, and the oil content is 7.1wt%.

[0065] (2) After removing the diluent solvent from the filtrate, dewaxed oil is obtained, and the mass yield of the dewaxed oil is 82.5 wt%.

[0066] (3) The temperature of the wax paste used for sweating is -23°C, the solvent content in the wax paste is 75wt%, the wax paste is placed in a sweating dish, the sweating starting temperature is -18°C, the heating rate is 3°C / h, the sweating ending temperature is 42°C, the constant temperature time is 2h, and the deoiled wax paste is obtained. The melting temperature of the deoiled wax paste is 45°C.

[0067] (4) After the sweating is completed, the diluent solvent in the deoiled wax paste is removed to obtain a low-oil wax product with a mass yield of 7.5%, a melting point of 55.4° C., an oil content of 1.14%, and a kinematic viscosity of 3.417 mm at 100° C. 2 / s, its oil content and melting point can meet the technical requirements of melting point and oil content of No. 54 semi-refined wax.

[0068] Comparative Example 2

[0069] Comparative Example 2 adopts the conventional solvent dewaxing and sweating method to remove oil from wax, and the heavy hydrocarbon oil feedstock B is the same as that in Example 2.

[0070] (1) A wax paste is obtained by the same method as step (1) of Example 2, and the diluent solvent is removed from the wax paste to obtain a dewaxed wax paste after desolventization, wherein the dewaxed wax paste has an oil content of 4.11 wt %, does not contain a diluent solvent, and the mass yield of the dewaxed wax paste is 17.5 wt %.

[0071] (2) Add 10% butanone to the dewaxed wax paste as a sweating raw material. Place it in a sweating dish and heat it to 55°C to melt, then cool it down to 35°C at a rate of 1.5°C / h. The wax paste will start to sweat after 5 hours of cold treatment. The sweating starting temperature is 38°C, the heating rate is 3°C / h, the sweating ending temperature is 54°C, and the constant temperature time is 2 hours to obtain a deoiled wax paste. The melting temperature of the deoiled wax paste is 57°C. After the sweating is completed, the diluent in the deoiled wax paste is removed to obtain a low-oil wax product with a mass yield of 6.7%, a melting point of 54.9°C, an oil content of 2.01%, and a kinematic viscosity of 3.500mm at 100°C. 2 / s, when the wax melting points are basically the same, its oil content cannot meet the technical requirements for oil content of No. 54 semi-refined wax.

[0072] Table 2

[0073] project Analytical methods <![CDATA[Kinematic viscosity (100 °C) / (mm 2 / s)]]> GB / T265 Freezing point / ℃ GB / T510 Pour point / ℃ GB / T3535 Distillation range / ℃ ASTMD6352 Melting point GB / T2539 Oil content GB / T3554

[0074] It can be seen from the results of reducing the oil content in wax in Examples 1 and 2 that by directly sweating the wax paste of the intermediate product of solvent dewaxing containing a diluent, a product that meets the oil content requirements of semi-refined paraffin can be obtained at a lower sweating temperature. Compared with the dewaxed wax paste without a diluent, the sweating temperature is low and the wax oil content is low.

[0075] It can be seen from the results of Examples 1-2 that, regardless of whether raw oil A or raw oil B is used as the raw material, the method of the present invention can be used to sweat and deoil wax paste containing a diluted solvent to prepare deoiled wax with reduced oil content.

Claims

1. A method for producing dewaxed oil and wax products from heavy hydrocarbon oil, characterized in that: include: (1) under dewaxing conditions, mixing a diluting solvent with a heavy hydrocarbon oil feedstock and performing solvent dewaxing, cooling to a filtration temperature, and performing solid-liquid separation on the wax-containing solution to obtain a dewaxing filtrate and a wax paste, wherein the content of the diluting solvent in the wax paste is 30 wt%-80 wt%; the diluting solvent is C3-C6 aliphatic ketone and / or C6-C8 aromatic hydrocarbon; (2) introducing the dewaxing filtrate into a dewaxing system to remove the diluting solvent in the filtrate to obtain a dewaxed oil with a lower pour point; (3) introducing the wax paste into a sweating system to heat and sweat to obtain a deoiled wax paste; (4) introducing the deoiled wax paste into a de-agent system to remove the diluent in the deoiled wax paste to obtain a wax product.

2. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, characterized in that: The heavy hydrocarbon oil raw material has a distillation range of 350-500°C and a solidification point of >25°C and is selected from vacuum distillate oil or solvent refined oil.

3. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, characterized in that: The diluting solvent is selected from one or more of acetone, butanone, benzene and toluene; Preferably, the dilution solvent is a mixture of butanone and toluene, wherein the volume content of butanone is 45v% to 70v%; Preferably, the volume content of butanone is 50v% to 65v%.

4. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, 2 or 3, characterized in that: In step (1), the diluent solvent is added to the heavy hydrocarbon oil once or several times, and mixed to obtain a mixed oil solution, which is cooled to a filtration temperature at a rate of 0.5 to 4°C / min, and high-freezing-point components are separated out at low temperature, and dewaxing filtrate and wax paste are obtained after solid-liquid separation; the temperature of the mixed oil solution when the diluent solvent is added for the first time is 25 to 70°C, the filtration temperature is -30 to -5°C, and the temperature of the wax paste is -30 to -5°C; Preferably, the temperature of the mixed oil solution to which the dilution solvent is added for the first time is 30 to 65°C. Preferably, the cooling rate is 1-3°C / min Preferably, the filtration temperature is -25 to -10°C.

5. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 4, characterized in that: In step (1), the mass ratio of the dilution solvent to the heavy hydrocarbon oil feedstock is 1 to 4.5:1; Preferably, the mass ratio of the dilution solvent to the heavy hydrocarbon oil feedstock is 1.5 to 4:

1.

6. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 4, characterized in that: Step (1) is carried out in a solvent crystallization stirring kettle, and during the cooling process of the mixed oil solution of the dilution solvent and the heavy hydrocarbon oil feedstock, the wall scraping stirring speed of the crystallization stirring kettle is 20 to 300 rpm; Preferably, the scraping stirring speed is 30 to 200 rpm.

7. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, 2 or 3, characterized in that: In step (2), the diluting solvent in the filtrate is removed by evaporation and gasification.

8. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, 2 or 3, characterized in that: In step (3), the wax paste is heated from the sweating start temperature to the sweating end temperature in the sweating dish and then kept at a constant temperature for 2 to 3 hours to obtain the deoiled wax paste; the sweating start temperature is 5°C higher than the temperature of the wax paste, the heating rate is 0.5 to 4°C / h, and the sweating end temperature is 10 to 25°C lower than the melting point of the wax product; Preferably, the heating rate is 1-3°C / h.

9. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 8, characterized in that: The sweating termination temperature is 16-20°C lower than the melting point of the wax product. The oil content in the obtained deoiled wax paste is 1.0-1.9wt%, and the diluent content in the deoiled wax paste is 1-6wt%. The melting point of the wax product obtained after removing the solvent is 50-70°C.

10. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 8, characterized in that: The sweating termination temperature is 13-20°C lower than the melting point of the wax product. The oil content in the obtained deoiled wax paste is 1.1-1.6wt%, and the diluent content in the deoiled wax paste is 2-5wt%; the melting point of the wax product obtained after removing the diluent is 55-65°C.

11. The method for producing dewaxed oil and wax products from heavy hydrocarbon oil according to claim 1, 2 or 3, characterized in that: In step (4), the diluent in the deoiled wax paste is removed by evaporation and vaporization.