RU2261263C2 - Process of treating hydrocarbon feedstock for further processing - Google Patents

Abstract

FIELD: crude oil treatment and petroleum processing.

SUBSTANCE: invention, in particular, relates to treatment of heavy high-viscosity crude oil or liquid hydrocarbon residues from refineries for their further deeper processing. Process comprises desalting and dehydration step and transportation of dehydrated crude oil into fractionation process. Before desalting and dehydration step or immediately after the same but before fractionation into commercial products, high-boiling fraction with boiling point 340-360°C and higher is recovered. This fraction is used to produce heavy commercial products such as bitumen, pitch, and coke. Separated lighter part of crude oil rich in desired fractions and depleted of harmful impurities is sent to further processing to produce light products. Preferably, high-molecular high-boiling fraction recovery step is combined with cracking of starting feedstock.

EFFECT: improved economical characteristics of petroleum distillation process.

2 cl, 3 dwg, 1 tbl

Description

The invention relates to the oil refining industry, and specifically to the field of preparation of heavy highly viscous oil, liquid hydrocarbon residues from oil refineries and other organic media for their further advanced processing, and can be used in the production of hydrocarbon fuel.

The decrease in oil reserves of traditional fields increases interest in the production and, consequently, in the processing of heavy oil (Ratov AN, Nemirovskaya GB and others. Problems of oil development in the Ulyanovsk region. "Chemistry and technology of fuels and oils", No. 4, 1995). Heavy oil is understood to mean oil with a density of more than 900 kg / m ³ , as a rule, with a low content of light fractions and a high content of tar-asphaltene substances and other undesirable impurities. These features of the composition of heavy oil cause serious difficulties both in production and transportation: high viscosity and pour points, and during its processing: a significant content of various impurities, resins. Transportation is significantly complicated due to the high content of tar-asphaltene substances and paraffin. Deposits on the working surfaces of equipment are the cause of its failure. And sulfur and metal compounds, especially vanadium, as well as chloride salts, which are usually found in such oil, have an increased corrosive effect on the equipment of oil refineries.

Currently, heavy oils are processed in a mixture with conventional light oil. Nevertheless, even in this case, the refining process causes great damage to the equipment of the refinery and the environment. It can be expected that over time the problem of refining heavy oil will become more acute: on the one hand, the demand for refining of such oil increases, as the reserves of light oil are depleted, and the reserves of heavy oil are quite large all over the world, on the other hand, the composition of oil products on the content of sulfur and metals.

Thus, the preparation of heavy oil for refining is a process that determines the profitability of the entire oil refining industry. The facilities for the preparation and primary processing of oil are the leading ones at oil refineries and the efficiency of their work largely determines the technical and economic indicators of the plant as a whole.

Known and widely used in industry are such methods of preparing the feedstock as dehydration and desalting of oil.

One of the most important measures to reduce corrosion and increase the service life of equipment is oil desalination. The oil supplied for refining at the facilities of oil refineries (refineries) is trained in the fields where it is freed from associated gas, part of light hydrocarbons, a significant amount of produced water and mechanical impurities. The salt content in marketable oil at present, as a rule, does not exceed 300 mg / l (according to GOST 9965 - 76, up to 1800 mg / l is allowed), water up to 1%. In the process of desalination, salts, some of the compounds of an acidic nature (fatty and naphthenic acids, acidic resins), as well as compounds of vanadium (50-70%), arsenic and nickel, which are partially concentrated on the surface of water globules, pass from oil to wastewater ( Levchenko D.N., Bergshtein N.V., Pinkovsky Y.I. Desalting of oil at oil refineries: Overview - Moscow: TSNIITENeftekhim, 1973. - 56 pp. These substances are part of the film and are emulsifiers that prevent fusion drops of water. Heavy metals, n Those contained in oil, even in small quantities, are poisonous for catalysts of thermocatalytic processes, reduce their operating time.Vanadium compounds, which are part of the ash deposits on furnace coils, lead to the formation of fusible compounds - eutectics - and accelerated corrosion of pipe metal in the melt. , such as naphthenic acids, have a catalytic effect on the degree of decomposition of organochlorine compounds of oil with the formation of hydrogen chloride in process atmospheres akuumnyh refining plants (AVT). Therefore, the desalination of oil and gas condensate is necessary even with a low salt content. Well-dehydrated and desalted oil at temperatures below 260 ° C has virtually no effect on the metal. The corrosion rate of carbon steel does not exceed 0.05 mm / year.

The simultaneous presence of hydrogen sulfide and hydrogen chloride (or chlorides) in the aqueous phase leads to increased corrosion of the equipment - up to 8 mm / year, while in steel saturated with hydrogen sulfide water the corrosion does not exceed 0.5 mm / year. It is not possible to reduce the formation of hydrogen sulfide using chemical-technological methods. Therefore, the removal of a large amount of chlorine-containing compounds (mineral and organic) from oil helps to reduce the low-temperature electrochemical corrosion of equipment at refineries.

A significant part of the corrosive impurities of oil is in drops of produced water, therefore, the essence of the process of desalination consists in the most complete removal of these drops from oil - dehydration. The process of desalination is associated with significant difficulties, since after field treatment of oil, very small drops of water remain in it. During transportation and storage of oil, a stable oil-water emulsion is formed.

The easiest way to desalinate oil is the currently widely used sludge of water droplets, which have a higher density than oil, and therefore settle into the lower part of the settling apparatus under the action of gravity. The deposition rate of these drops, which is proportional, according to Stokes law, to the square of its diameter and the difference in the density of oil and water and inversely proportional to the viscosity of oil, is very small for the smallest drops and is comparable with the Brownian motion and natural convection speeds. When such water droplets collide, their coalescence does not occur, since a strong hydrophobic film prevents this. According to many researchers, the composition of the film includes paraffin microcrystals, asphaltenes, resinous substances, organic acids, as well as metal-porphyrin complexes of vanadium, nickel, iron, magnesium (Levchenko D.N., Bergshtein N.V., Pinkovsky Y.I. Desalination of oil at oil refineries: Overview. - M.: TSNIITENeftekhim, 1973. - 56 pp. Levchenko DN, Bergshtein NV, Nikolaeva NM Technology of desalination of oil at oil refineries. - M .: Chemistry, 1985, - p.6).

In the process of desalination, the film around the droplets is destroyed and partially carried away with the wash water. At low temperatures, when the viscosity of the oil and the effect of surface forces are most significant, precipitation of water from the emulsion is almost not happening. To carry out the process of oil desalination, it is heated, treated with a demulsifier, flushing water is fed into it and introduced into an electric field. With increasing temperature (up to some limits), the viscosity of the oil and the mechanical strength of the films around the water globules decrease. As a result, the solubility in oil of the components of this layer increases and the difference in the densities of water and oil increases (in the temperature range from 0 to 120 ° C, oil has a larger coefficient of volume expansion than water).

A demulsifier introduced into oil is adsorbed on the surface of water globules, forming a hydrophilic film, i.e., also helps to reduce the strength of the armor layers around water droplets. As a result, the coalescence of water droplets, their coarsening and precipitation is facilitated. The acceleration of the separation of oil and water phases occurs in an electric field. Most of the electric desalting plants (ELOU) of domestic refineries consists of two stages of desalination or three, designed for heavy hardly desalted oil.

It is advisable to introduce rinsing water to reduce the corrosion of tube bundles of raw heat exchangers in front of electric dehydrators (dehydrators). Currently, as a rule, fresh washing water is supplied to the last stage of desalination, and wastewater from each stage is used as washing in the previous stage. Reducing the proportion of fresh washing water containing dissolved oxygen, helps to reduce the corrosion of apparatuses, sewage pipelines ELOU. Since the main stages of the process of desalting oil at ELOU is the dispersion of washing water and the coalescence of drops of formation and washing water (i.e. effective mixing of oil with reagents), when designing ELOU, special attention should be paid to achieving effective mixing of oil with washing water using various dispersants (Gershuni S.Sh. Modernization of electric dehydrators ways to improve the efficiency of their use: Overview. - M .: TSNIITENeftekhim, 1986. - 64 p.). These include emulsion valves, injectors, adjustable mixers, various types of throttle devices. Despite the variety of designs of dispersants, their performance is mainly determined by the pressure drop created in them. Recently, nozzle-type constructions are used more and more widely, in which only water, and not a mixture of oil and water, is passed through the throttle device (Umutbaev V.N., Savkova V.G., Prokopyuk S.G., Lyamin V.A. / Chemistry and technology of fuels and oils, 1985, No. 8, p. 8). At the same time, the hydraulic resistance to oil is reduced, the atomization fineness is increased, water consumption and energy consumption are reduced. The following basic requirements are imposed on a water dispersant: obtaining the dispersed composition of water that is optimal for specific conditions and the uniform distribution of water droplets over the entire volume of oil. The coalescence process begins in the dispersant, but it is quite long. Therefore, the dispersant should be installed as far as possible from the electric dehydrator so that the coalescence process continues in the pipeline.

Currently, the issues of reducing the consumption of demulsifier and fresh water at ELOU, as well as the possibility of using only process condensate from primary oil refining plants for desalination, are being addressed. The possibility of using condensate should be determined by the degree of its corrosiveness. So, the greatest increase in carbon steel corrosion in aerated water is observed at a concentration of hydrogen sulfide up to 25 mg / l, and the presence of chlorides in this medium leads to the development of ulcerative corrosion (Kessel IB, Bergshtein N.V., Levchenko D.N., Zakharov L.I. / Oil refining and petrochemistry, 1981, No. 5, p.5). The ingress of oxygen into the condensate is possible in a tank designed to collect water and not having a protective atmosphere of inert gas, or when diluted with fresh water. The demulsifier promotes the washing of the surface from corrosion products and thereby facilitates the flow of the electrochemical corrosion process. The corrosion rate of steel increases with decreasing pH of the condensate, i.e. during the transition from alkaline to acidic. Therefore, the condensate of a vacuum column containing acidic compounds, chlorides, hydrogen sulfide (the quantitative composition depends on the type of oil being refined) and lacking an inhibitor or ammonia additives to reduce equipment corrosion is more aggressive than the condensate of a pre-evaporation column or atmospheric oil. The corrosion rate of carbon steel in the effluent of ELOU, depending on the quality of the wash water, the type of oil being processed and the use of neutralizers, is in the range from 0.12 to 1 mm / year, and during the processing of sour oil can be more than 1 mm / year (Kessel I .B., Bergstein N.V., Levchenko D.N., Zakharov L.I. / Oil refining and petrochemicals, 1981, No. 5, p.5). Therefore, when using condensate from ABT installations, it is advisable to provide for its appropriate preparation before feeding it into oil: blowing off hydrogen sulfide, bringing the medium to neutral or slightly alkaline. The resulting hydrogen sulfide reduces the pH of the aqueous phase (pH <6), which increases the corrosion of equipment and makes oil desalination difficult (Skalozub F.I., Levchenko D.N. / Oil refining and petrochemicals, 1980, No. 11, p.10). The service life of tube bundles of raw carbon steel heat exchangers under these conditions can be reduced to 3-4 months. For each type of oil, the optimal desalination temperature is recommended: for West Siberian 70 ° C; for Romashkinskaya, Kama, Mangyshlak and Turkmen 100-120 ° С; and for some very heavy and viscous, for example Arlansky, 120-140 ° С (Levchenko D.N., Bergshtein N.V., Pinkovsky Y.I. Desalination of oil at oil refineries: Overview. - M .: TSNIITENeftekhim, 1973 . - 56 p.).

When developing anticorrosion measures, it is necessary to take into account the temperature of the oil at ELOU, the content in the produced water of alkali metal bicarbonates, magnesium chlorides, sulfur-containing compounds with low thermal stability. To increase the pH of the aqueous phase to 8.0-8.5, it is necessary to introduce a weak solution of sodium hydroxide into the crude oil. The corrosion rate of carbon steel in ELOU effluents during the processing of sulphurous oils and pH 8.0 is ~ 0.12 mm / year. At pH> 8.5, an undesirable transition of petroleum products to ELOU effluents is observed. In addition, uncontrolled consumption of alkali can lead to alkaline brittleness of the metal, disrupt the operation of insulators in electric dehydrators. If there are three stages of desalination from oil, it is possible to remove some of the chlorides that make up the organochlorine compounds of oil by alkaline treatment (alkalization) under certain conditions. It should be expected that in this case, in addition to sodium chlorides, naphthenates and sulfides can partially transfer to the aqueous phase. Practice has shown that when even a deep desalination of oil is achieved and alkaline treatment of desalted oil with ABT stops, the corrosion of condensation-refrigeration equipment in primary oil processing plants increases sharply. The reason for this is the presence of organochlorine compounds in oil, which, like organosulfur compounds, have unequal thermal stability. The alkalization of demineralized oil on AWT has its drawbacks. The amount of alkali introduced, or rather sodium chloride formed, remains in the fuel oil, increases its ash content, and contributes to burnout of the furnace coils. At catalytic cracking units, poisoning of the catalyst and its deactivation by sodium chloride are possible. Abroad, in the processing of tar, fuel oil at catalytic and thermal cracking plants, alkalization of demineralized oil at AWT is not carried out. This is explained by the requirement to improve the quality of asphalt used for paving. The sodium chloride contained in such a coating is easily washed out with water, which leads to rapid mechanical destruction of the asphalt coating. In addition, this method of alkalization of oil after ELOU is considered unsuitable, as it leads to deposits of salts in the gasoline and kerosene sections of distillation columns and contamination of control valves and plates. Salts cannot be excluded from hydrotreating diesel fuel due to their mechanical entrainment.

The work of VNIINeftemash showed the possibility of removing part of organically bound chlorine on ELOU. To do this, after the first stage of desalination at ELOU, an NaOH solution of at least 1% concentration is introduced into the oil containing ~ 12 mg / l of salts. The resulting metal chlorides (e.g. sodium) are removed from the apparatus with drainage water. Estimated alkali consumption is 20 g / t.

The process of alkalization of oil on ELOU has the following features. Oil temperature should not be lower than 120 ° С. It is necessary to ensure intensive mixing of the alkaline solution with oil, which is achieved by fine dispersion of the alkaline agent, its uniform distribution in the stream, eliminating the separation of the stream. Processing time should be at least 30-60 s. After alkaline treatment, water washing is provided, with the help of which alkali removal to the ABT is prevented. To achieve intensive mixing, which provides the required degree of contact of the reagent with oil, various mixers are used: remote or built-in to electric dehydrators. The most effective way to mix oil with a reagent (water, alkaline solution, demulsifier) is mixing in an electric field; it occurs 4-6 times more intensively than in a turbulent flow.

As can be seen from the foregoing, such oil preparation processes as desalination and dehydration are rather complicated in terms of equipment composition and operation, energy consumption, and a large amount of wastewater causes enormous damage to the environment. Processes such as alkalization lead to a deterioration in the properties of the resulting commercial products, such as asphalt. In addition, various impurities contained in the feedstock, such as acid resins, compounds of vanadium, arsenic, nickel and others, which are partially concentrated on the surface of water globules, are part of the film and are emulsifiers that impede the processes of dehydration and desalination.

The above methods for the preparation of oil solve a specific narrow problem, but do not significantly purify the original oil from other harmful compounds, such as sulfur compounds, organochlorine, tar-asphaltene substances, paraffins, which interfere with further oil refining. Practically no methods are used in industry for the purification of initial oil, especially heavy and sour, from sulfur compounds.

The technical result, which is achieved by the proposed method, is to implement a substantially comprehensive purification of the feedstock immediately from many undesirable components and harmful impurities, which allows further independent (for example, without dilution with light oil) in-depth and cost-effective processing of heavy high-viscosity oil with a possible increase in productivity and service life of standard equipment of the oil refinery.

The technical result is achieved by the fact that in the method of preparing liquid hydrocarbon raw materials for further processing, including the stage of desalination and dehydration and the direction of the prepared oil for further processing by dividing it into fractions and obtaining marketable products, to the stage of desalination and dehydration or immediately after, but before the stage of separation of hydrocarbons into fractions (before feeding to AT or ABT) emit high molecular weight high boiling fractions (VKF) with a boiling point of 340-360 S. After this stage, the second part of the oil contains lower boiling fractions (NKF) and is an "improved" oil containing significantly less harmful impurities. Fractions (VKF) contain the main amount of tar-asphaltene substances, paraffins, sulfur, sulfur compounds and metals, which are not involved in the further processing of “improved” oil. For example, for oil produced in the Ulyanovsk region, the mass fraction of sulfur and sulfur compounds in the “improved” oil after the separation of VKF decreases from 4-5 wt.% To 0.5-0.7 wt.%. Accordingly, the mass fraction of chlorides is from 500-5000 mg / l to 20 mg / l. In addition, the bulk of metals, such as vanadium, also goes into VKF. At the stage of separation of VKF, in addition, at the same time, a cracking process, for example thermal, can be carried out. Thermal cracking for heavy oil, for example, oil from the above fields, has features: the onset temperature of decomposition is 238 ° C at a residual pressure of 0.25 kPa (Soskind D.M., Ratov A.N. Small-tonnage complex for the processing of oils from the Ulyanovsk region with associated extraction of vanadium / Chemistry and technology of fuels and oils, No. 1, 1996). Starting from 410-420 ° C, thermal cracking proceeds at high speed. The temperature of the process of allocation of VKF should be in the range of 340-420 ° C. This increases the amount of light fractions in the feedstock for further processing at standard refinery equipment. At the stage of sulfur hydrotreating, gasoline fractions after AT arrive at a content of 0.1-0.2%. Such a content of sulfur and sulfur compounds corresponds to their level during the processing of low-sulfur oil, for example, West Siberian. The VKF fraction in an amount depending on the composition of the oil is sent further directly to obtain marketable products: bitumen or other heavy products (pitch, coke, etc.). For Ulyanovsk oil, this amount is 25-30% of the mass of the original oil. Sulfur compounds do not interfere with the production of quality bitumen. It is believed that the sulfur compounds of the processed raw materials do not play a direct role in the conversion reactions, but they are oxidation accelerators in the process of bitumen production, as well as effective plasticizers. This reduces the time of the oxidation process and the products of such accelerated methods have a smaller change in consistency with a change in temperature (Gruze V.A., Steven D.R. Oil refining technology. L., Chemistry, 1964, p. 550, 551).

Thus, the selection of high-boiling fractions with a boiling point of 340-360 ° C can be realized after oil production to the stage of its traditional preparation, including dehydration and desalination, carried out at the refinery. In this case, it is possible to transport only “improved” oil to the refinery, and VKF is used as raw material for the production of bitumen at the place of oil production. Or it is possible to isolate VKF at a refinery immediately after oil preparation as an additional stage in the sequence of stages of a classical technological process.

As a result, fractions with a boiling point of 340-360 ° C are obtained not at the end of the sequence of stages of ELOU-AT, but at the beginning of the processing process. After the separation of VKF, the further sequence of stages of oil refining does not differ from the sequence of stages of refining of light oil. In this case, the refinery equipment operates in a sparing mode, since it does not process heavy initial high-viscosity oil containing undesirable impurities from the point of view of preserving the resource of the equipment and the quality of the products obtained, but “improved” oil enriched with light in relation to the initial oil, fractions with a boiling point up to 350 ° C. The resource of equipment for the processing of heavy oil in this case (subject to preliminary allocation of VKF) is not less than the resource of the corresponding equipment for processing light oil. Isolation of a part of it (VCF) from oil in an amount of 25-30% (depending on the composition of the oil) reduces the subsequent material flow of feedstock for processing, but with or without a slight increase in light fractions. Technological apparatuses may have a lower throughput, but the amount of light petroleum products obtained is preserved, or productivity can be increased on the same equipment. This is due to the fact that VKF does not go through the entire technological chain of AT devices, but is withdrawn at the beginning of the technological process and sent further as raw materials for vacuum processing, or as raw materials for the production of bitumen.

The VKF separation process can be implemented using an evaporator, the design of which is similar to the well-known and widely used evaporator-heat exchanger with a steam (in steam form - NKF) space (Dekhterman A.Sh. Oil refining according to the fuel version. M., Chemistry, 1988, p. 23). Unlike simple heat exchangers, this apparatus has enough volume to evaporate the heated product. The evaporator is a cylindrical tank. At the bottom of its housing is an integrated tubular heat exchanger. A coolant is supplied inside the tubes of the heat exchanger to heat the product (oil). Typically, water vapor is used as a heat transfer medium. A light portion of the oil evaporates and is discharged through the top fitting. The remaining oil is poured through the drain plate and is discharged through the corresponding fitting. The amount of evaporated part of the oil depends on the temperature in the apparatus, that is, on the surface of the heat exchanger and the temperature of the coolant. Water vapor also satisfies other requirements for heat carriers: availability, fire safety, etc. The main disadvantage of water vapor is a significant increase in pressure with increasing temperature, therefore, to obtain a temperature in the device in the range of 340-420 ° C, it is necessary to use high-temperature heat carriers. As high-temperature coolants, it is advisable to use: high-boiling organic liquids, molten salts or liquid metals (Kasatkin A.G. Main processes and apparatuses of chemical technology. M., Chemistry, 1971, p.334-338).

Figure 1 shows the step-by-step scheme of oil refining, in which the selection of high-boiling fraction is carried out after the stage of oil preparation, including dehydration and desalination.

Figure 2 presents a schematic diagram of a pilot installation.

Figure 3 shows the frictional composition of oil and oil products.

Table 1 shows the properties of oil from the Ulyanovsk Region, oil from the West Siberian and oil products obtained at the pilot plant.

The proposed method is implemented in a pilot installation for the separation of oil with a capacity of up to 0.2 t / h.

The installation consists of the following devices. The steam generator 1 is designed to produce saturated steam with the following parameters: pressure - 1.18 MPa, temperature - 187 ° C. Comparator 2 is designed for pumping non-condensable gases from technological devices. The electric heater 3 with an adjustable power source has a maximum power of 50 kW, the temperature of the heating medium (steam) up to 650 ° C. At these temperatures, as a rule, intense thermal cracking of the feed occurs. Evaporator 4 with integrated heat exchange equipment and insulation. Recuperative heat exchangers 5, 6 and 7, structurally designed as a “pipe in pipe”. Shell-and-tube heat exchangers 8, 11 and 13, cooled by running water. Separators 9, 10 of the vertical type for the separation of gas-liquid mixtures into phases: liquid and gas. Packed distillation column 12, with a diameter of 150 mm, a height of 4 m, is filled with ceramic elements in the form of Rashig rings with a characteristic size of 10 mm. The column has a remote boiler, heated by superheated water vapor, and a reflux condenser, with the ability to control the flow of reflux for column irrigation. The unit is equipped with sealed containers 14-19 for collecting and storing the original oil and its separation products, as well as instrumentation and equipment for maintaining process parameters in a given range of values and safe operation.

The process was carried out as follows. Oil from the supply tank 14, preheated to a temperature of 100-150 ° C in recuperative heat exchangers 6, 5, was supplied to the evaporator 4. A heat carrier with a temperature of 420-650 ° C was also supplied to the heat exchanger of the evaporator 4. The coolant used was superheated water vapor or an inert gas, which was heated to the required temperature in heater 3. The use of a gaseous coolant is justified in laboratory conditions, as it simplifies the design of the heater used. By controlling the flow rate of the coolant and its temperature, they provided the necessary heating and maintaining the temperature in the evaporator to achieve the required amount of emitted VKF with a boiling point of about 340-360 ° C, as well as for carrying out the process of thermal cracking of the feedstock. Since the process of simple distillation is carried out in the evaporator, a clear separation of the fractions was impossible in this case. In the NKF, partly the NKF is present, and in the NKF, partly the NKF. The quantity and qualitative composition of the VKF was determined at the outlet of the evaporator 4 until it was sent to the collection 16.

The low boiling fractions, after separation of the HCF, were sent through a heat exchanger 5 and a refrigerator 8 to a separator 9. If unprepared oil, that is, oil containing water, was used for the refining process, then water and steam were removed from the evaporator together with the NFC. In the separator 9, the mixture was separated into water, liquid hydrocarbons, and “reflux” gas. Water was sent to steam generator 1, “reflux” - gas through a compressor 2 to the gas collector 19, the liquid part of the NKF to the collector 18. If prepared oil was used, then there is no water in the joint stream with the NKF. In this case, the NKF in steam form was fed directly to the distillation column 12. In the diagram (figure 2), this NKF supply line is shown by a dashed line. After monitoring the quality of the medium in the collection 18, the NCP was heated in the heat exchanger 7 and fed to the packed distillation column 12, where there was a clear separation with the selection of two narrow target fractions. From the top of the column, part of the rectified product condensed and cooled in the refrigerator 11 was taken; from the bottom of the column, the heavy part of the rectified product was selected, which was cooled in the refrigerator 13. This made it possible to fully analyze the products obtained: gasoline (with a boiling point up to 200 ° C) and diesel (in the range of boiling temperatures 200-350 ° C) fractions that accumulated in the collectors 17 and 15.

As the source of raw materials used oil field Vishenskoye Ulyanovsk region. (Ratov AN, Nemirovskaya GB and other problems of oil development in the Ulyanovsk region / Chemistry and technology of fuels and oils, No. 4, 1995). Oil contains a significant amount of resinous compounds and impurities. To study the applicability of this technology, oil of other fields was used, respectively, with a different composition. The technological process was developed at this installation, including the stage of separation of the high boiling fraction. Complete analyzes of the composition of the obtained fractions were made: high boiling fractions with a boiling point of 340-360 ° C and "improved" oil. Their properties were studied for the purpose of further processing according to the classical scheme. Further processing of the “improved” oil was carried out, reproducing most of the operations (except hydrotreating and catalytic reforming) according to the classical scheme in order to obtain fuel components and study their properties.

Figure 3 shows a typical fractional composition of the original oil (Vishenskoye field, Filippovskaya group. Ulyanovsk region) and the products of the process of separation of high boiling fractions from the specified oil. For comparison, the same figure shows the fractional composition of West Siberian oil, Samotlor field. The main properties of the compared oils and fractions are in table. 1. As can be seen from the data presented, when the VKF fraction is extracted from the initial oil in the proposed process in an amount of about 25-30% (wt.), The viscosity of NKF is significantly reduced and it is enriched due to cracking with light hydrocarbons. In this case, the bulk of the impurities goes to VKF. Recalculation of the amount of products obtained for the initial heavy oil shows that the yield of light fractions with a boiling point up to 350 ° C is 55-59%. This amount is comparable to the potential yield of similar products from Samotlor oil.

Thus, the technical result is a comprehensive preparation and purification of the feedstock from many undesirable impurities at once, which allows for further independent (for example, without dilution with light oil) in-depth and cost-effective processing of heavy high-viscosity oil with a possible increase in productivity and service life of standard equipment of the refinery - achieved by the allocation of high-boiling oil fractions in the initial stage of oil refining, containing mainly products kty with a boiling point of 340-360 ° C and above. These fractions, containing the bulk of undesirable components and harmful impurities of the original oil, are then used to prepare heavy commercial products such as bitumen, pitch, coke, etc., and the remaining light portion of the oil, enriched in the target fractions and depleted in harmful impurities, is sent for further processing for obtaining light petroleum products using standard equipment of oil refineries.

Table. one
Properties: oil of the Ulyanovsk region and oil of the West Siberian; petroleum products obtained at the pilot plant. Product Density, g / cm ³ Viscosity, cSt Sulfur,% Chlorides, mg / L The yield of fractions,% up to 200 ° C up to 350 ° C Cherry Oil 0.9482 72.9 (50 ° C) 3.91 500-5000 8.3 30,0 Samotlor Oil 0.8426 6.1 (20 ° C) 0.96 500-1500 30.6 58.2 NKF ("improved" oil) 0.79-0.81 1.8 (20 ° C) 0.5-0.7 20-30 23-28 * 55-59 * VKF 0.99-1.1 260 (50 ° C) 5.0-6.0 1000-3000 0 5-6 * ^* In terms of the original oil before separation.

Claims (2)

1. A method of preparing liquid hydrocarbon feedstocks for further processing, including the stage of desalination and dehydration and the direction of the prepared oil for further processing by separating it into fractions and obtaining marketable products, characterized in that prior to the stage of desalination and dehydration or immediately after, but before separation high molecular weight high boiling fractions containing mainly products with a boiling point of 340-360 ° C and above, which contain mainly e the amount of undesirable components and harmful impurities of the feedstock, which are used for the preparation of heavy commercial products such as bitumen, pitch, coke, etc., and the remaining light portion of the feedstock, enriched in target fractions and depleted in harmful impurities, is sent for further processing to obtain light petroleum products. 2. The method according to claim 1, characterized in that the stage of separation of high molecular weight high boiling fractions is combined with the cracking process of the feedstock.

Images