SU490295A3 - Method for hydrotreating asphalt-containing petroleum feedstock - Google Patents

Description

Zai with the necessity of conversion of the bottom residue from raw refineries. The increased demand for fuel oil is made necessary by the 100% use of crude oil.

In accordance with the proposed combined process with the desulphurisation of crude oils, atmospheric tar oils, vacuum tar oils and heavy catalytic feeds, fuel oil, crude oil, heavy hydrocarbon products separated from bituminous sands, etc., low-sulfur fuel oils, crude petroleum and heavier hydrocarbon fractions and / or distillates, with the feedstock containing nitrogenous and sulfur compounds in excessively large quantities (from 2.5 to 6.0 wt.%, in terms of elemental gray sulfur). In addition, these metal hydrocarbon fractions contain organometallic compounds, including nickel and waiadium in the form of orphirins, and high molecular weight asphalt material. Such raw materials are vacuum tar with a density of 1.0209 and containing 4.05 wt. % sulfur and 23.7 wt. % asphaltenes: mid-eastern crude oil with a density of 1.9930 and containing 10.1 wt. % asphaltenes and 5.20 weight. % sulfur; vacuum residue density of about 1.0086 and containing 3.0 weight. % sulfur, 0.43 weight. % nitrogen with a temperature of 20% boil-off around 567 ° C. Using the process provided by the invention provides the maximum yield of low-sulfur fuel oil from this heavy hydrocarbon feedstock.

The drawing is a diagram of the process of obtaining fuel oil, soda, which is less than 1.5 wt. % sulfur from lubricating oil.

The hydrotreating process consists of the interaction of a hydrogen feed in the first catalytic reaction zone under the conditions of the desulfurization chosen to convert the sulfur compounds into hydrogen sulfide and hydrocarbons; separating the resulting effluent of the first reaction zone in the first separation zone to produce a primary, mainly vapor phase, and a primary, mainly liquid phase; separating hydrogen sulphide from the primary vapor phase and reacting at least part of said liquid phase with the resulting vapor-phase substantially free of hydrogen sulphide in the second catalytic reaction zone under conditions of desulfurization chosen to convert additional sulfur compounds into hydrogen sulphide and hydrocarbons; separating the resulting effluent from the second reaction zone in the second separation zone to form a secondary vapor phase and a secondary liquid phase; on a minor basis, returning a part of the secondary vapor phase to the first reaction zone for reacting with the raw material and separating fuel oil from the secondary liquid phase.

Variants of the inventive scheme consist in various technological methods and variations of catalyst mixtures for application in a catalytic reaction zone with 5 fixed beds. For example, in one such scheme, the primary vapor phase is separated in a third separation zone to produce a tertiary vapor and tertiary liquid phase. In another such scheme, a portion of the common liquid is combined with the neural vapor phase prior to the removal of hydrogen sulfide from it. The invention uses two fixed bed catalyst reaction systems in combination with a group of separation devices that provide more efficient use of hydrogen during the whole process. Such a reaction system may consist of one or more reactors equipped with a sufficient number of heat exchangers between them. The combined process is carried out due to the initial reaction of the feed with a relatively unpurified hydrogen stream in the first recovery zone. In fact, in the first reaction zone, relatively easy desulfurization of low-boiling sulfur compounds is provided. The effluent separates at the same temperature and pressure to produce a high liquid, usually liquid phase, which reacts in the second reaction system with a relatively pure hydrogen phase. The operating conditions in both reaction systems are: pressure 14.06-210.9 kg / cm, 5 hydrogen circulation 89.05-5346, hourly space feed rate from 0.25 to 2.50 and maximum temperature of the catalyst bed within 315.6-482.2 ° С. In order to facilitate passage of the product, the second reaction zone is maintained under pressure (at least 1.75 kgf / cm) more than in the first reaction zone. The maximum temperature of the catalyst layer in it is 5.5 ° C higher than in the first 5 reaction zone.

The advantages of the proposed process are numerous. However, the main one among them is a significant lowering of the maximum temperature of the catalyst layer to achieve the desired degree of desulfurization. Thus, while the maximum temperature of the catalyst bed may be within 315.6-482.2 ° C, a combined process is often carried out at maximum temperatures of the catalyst bed below 454.4 ° C. In addition, the combined process allows the use of an unpurified hydrogen stream to ensure the desulfurization of low-kinetic sulfur compounds in the initial reaction zone. Another advantage is associated with an increase in the effective life of the catalyst used in both reaction zones. The catalyst mixtures may be identical in both contact zones. Catalyst mixtures contain metallic elements selected from metals of groups VI and VIII of the periodic system, as well as their compounds. Thus, suitable metallic elements are selected from the group consisting of chromium, molybdenum, tungsten, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium and platinum. In addition, recent studies have shown that catalytic compositions used, in particular, for the conversion of feedstocks with a very high sulfur content, are improved by the introduction of ionic and / or bismuth. The component implies the presence of a metal as a compound, such as oxide, sulphide, etc., or a metal in an elemental state. Despite this, the concentrations of the metal compounds are calculated based on the fact that the metal is in the mixture in an elemental state.

Since the raw materials for the process are of a high boiling nature, it is desirable that the catalytically active components have a tendency to hydrocracking is limited, at the same time, they accelerate the conversion of sulfur compounds into hydrogen sulfide and hydrocarbons. The concentration of the catalytically active metal component or components depends on the metal itself, as well as on the physical and / or chemical properties of the raw material. For example, the metal components of group VI are usually present in an amount of 4.0-30 weight. %, iron group metals in the amount of 0.2 to 10 wt. %, noble metals from group VIII, preferably 0.1 to 5.0 weight. % When using a component of zinc and (or) bismuth, noble metals are usually present in an amount of 0.01-2.0 weight. %

The porous carrier material, to which the catalytically active metal component or components are bonded, contains a refractory inorganic oxide, preferably alumina, or alumina in combination with 10-90 wt. % silica. When processing heavy feeds containing significant amounts of hydrocarbons having normal boiling points above 510 ° C, it may be acceptable to use a carrier containing crystalline aluminosilicate or a zeolitic molecular sieve. In most cases, such a carrier will be used in the processing of partially desulfurized raw materials in the second reaction zone. Suitable zeolitic material includes mordenite, pajazite, molecular sieves A or Y, etc., and they can be used in an exceptionally pure state. However, the zeolite material may be included within an amorphous matrix, such a PDA is silica, alumina, and a mixture of alumina and cremiezem. Catalytic mixtures may include a halogen component from the group including fluorine, chlorine, iodine, bromine

and mixtures thereof. The halogen component will be mixed with the carrier so that in the finished catalytic crxiecH the content of the halogen component is 0.1-2.0 weight. %

The metal components may be introduced into the catalyst in any suitable manner, including coprecipitation or co-gelatinization with a carrier material, ion exchange or impregnation of the carrier material, or during combined extrusion. After the metal components are introduced, the carrier material is dried and subjected to high-temperature calcination or

oxidation at 398.9-704.4 ° C. When crystalline aluminosilicate is used inside the carrier material, the upper calcination treatment limit is preferably 537.8 ° C.

The working forces of the catalytic reaction zones are selected to desiccate the conversion of sulfur compounds to hydrogen sulfide and hydrocarbons. The operating conditions created in the second reaction zone are often

lead to greater rigidity of the regime, although such technology is necessary. Differences in working stiffness levels between the two reaction zones can be achieved by controlling the pressure, the maximum temperature of the catalyst bed, and the variable fluid hourly space velocity. More stringent conditions inside the second reaction zone usually occur at elevated pressure, and the increased maximum temperature of the catalyst layer, and a somewhat lower liquid hourly space velocity, or for some combination of these factors. The suitable limits for the different operating variables are basically the same for both reactionary systems. Thus, the pressure is in the range of 14.06 - 210.93 kg / cm. the hydrogen concentration is about 89.05-5346, the maximum temperature of the catalyst layer is within 315.56-482.2 ° C, and the volumetric flow rate of the liquid is 0.25-2.50. The reactions taking place are mostly exothermic, in both reaction zones there will be

An increase in the temperature gradient was confirmed, since the substances involved in the reaction cross the catalyst bed. The preferred operating mode requires an elevated temperature gradient.

was limited to a maximum of 37.7 ° C, to control the temperature gradient using cooling streams, liquid or gaseous, introduced into one or several intermediate points of the catalyst bed. For example, if the pressure at the inlet to the reactor is about 161.7 kgf / cm, and the temperature is about 371.1 ° C, the same pressure and temperature (equal to 154.68 kgf / cm) and part of

the first, mainly the napoBoii phase is introduced into the second reaction zone, allowing the removal of hydrogen sulfide from it, while a part (in this case, a multiple of the first), of the mainly liquid phase, is circulated with fresh raw materials. Example. Scheme of industrial installation designed to obtain maximum amounts of fuel oil containing less than 1.0 wt. % sulfur from residual raw materials, the density of which is equal to 0.9574. Other properties of the raw materials include a sulfur content of 4.0 wt. %, 0.006 weight. % vanadium and nickel, 2.4 wt. % of material insoluble in heptane, Conradson carbon factor of 8.2 and 65.0%, kineni point corresponds to a temperature of 565.6 ° C. Raw materials are introduced into the process via pipeline 1 in an amount of about 740.35 mol / h. This feed is mixed with hot (365.6 ° C) circulating gaseous phase from line 2, with the latter containing about 76.0 vol. % of hydrogen. The mixture goes along pipeline 2 and flows from it to reactor 3 with a temperature of 344.2 ° C and a pressure of 189 kgf / cm. The reactor 3 contains a catalytic mixture of 2.0 wt. % nickel and 16 wt. % molybdenum together with an amorphous carrier material consisting of 88.0 wt. % of alumina and 12.0 weight. % of silica, wherein the liquid hourly space velocity is about 1.0. The effluent from the reactor 3 is pumped through line 4 with a temperature of 365.6 ° C and a pressure of 151 kgf / cm and sent to a hot separator 5 at the same temperature and pressure. The hot separation zone 5 serves to create a liquid phase in line 6 and a vapor phase in line 7. The fractional composition of the product leaving the first reaction zone (line 4), the liquid phase of the hot separator (line 6) and the hot phase of the separator (pipeline 7) are presented in table. 1. The vapor phase in line 7 is displaced from 1420.00 mol / hour of the circulating stream of cold distilled liquid, the source of which is described below. The mixture is withdrawn through line 7 and introduced into the cold separator 8 under a pressure of 147.6 kgf / cm at a temperature of 59.7 ° C. The vapor phase containing a large amount of hydrogen is withdrawn from the cold separator through conduit 9 and withdrawn through it to a hydrogen sulfide collector 10. The substantially liquid phase is withdrawn through conduit 11 and drawn through it into the cold stripper 12 at the same temperature. The cold stripping zone operates at a pressure of about 140.6 kg / 1 cm and a temperature of 57 ° C to create an exhaust gas flow in conduit 13 and a flow of liquid phase in conduit 14, part of which is returned for mixing with the vapor phase in conduit 7, thereby forming an enriched The hydrogen stream, the fractional composition of the enrichment of the hydrogen stream in the pipeline 9, the solid gas stream in the pipeline and the liquid product in the pipeline 14, which is stabilized for product recovery, are presented in Table. 2. Tbl II c 2 Component 1 mols / hour in the pipeline Wash water flow is introduced into the process through pipeline 15. This water is removed from the process through a submersible knee in a cold separator. The system for removal of hydrogen sulfide from the collector 10 increases the concentration of hydrogen in the recirculation gas in pipeline 16 to 5.9%. To compensate for this consumption in the process, as well as the loss of the solution, fresh hydrogen is introduced through line 17. The hydrogenated phase is mixed with the liquid phase in line 6, to which 809.72 mol / h of water is additionally introduced through line 15, the mixture is passed through line 16 to the second reaction zone 18 under pressure of 165.2 kgf / cm at 360, 5 ° C. The reaction zone 18 contains a catalyst mixture of 1.8 wt. % nnkel and 16.0 weight. % molybdenum mixed with a carrier material (63.0 wt.% alumina and 37.0 wt.% silica). Here, the liquid hourly space velocity is about 1.5. The product leaving the reaction zone 18 is removed via conduit 19 and sent to a hot separator 20 with a pressure of about 158.3 kgf / cm2 at a temperature of 365.6 ° C. The vapor phase is removed through conduit 2 and returned for mixing with the raw material in conduit 1. Typically, the liquid phase is withdrawn through conduit 21 and combined with the liquid phase in conduit 14, the product of which is sent to the separation unit to produce the desired fuel oil. The fractional composition of the products entering the reactor 18 (pipeline 16) and the products leaving it (pipeline 19) are presented in Table. 3

Table 3

T a b l 11 c a 4

ten

20

T a b l 1

The separation carried out in the hot separator 20 is illustrated in table. four.

The overall distribution of the product and the yield of the components are presented in table. 5. This includes the product that is discharged into the hydrogen sulfide removal system 10, the exhaust gas stream in conduit 13 and the liquid product exiting through conduits 14 and 21.

Petroleum in heptane fraction 190 ° C has a density of 0.8473, contains less than 0.05 wt. % sulfur; gas oil fraction with boiling point, has a density of 0.8473 and contains less than 0.1 weight. % sulfur; all fuel oil boiling at a temperature of about 343.3 ° C has a density of 0.9248. and contains: melee.

0.3 weight. % seoi;

Subject invention

The method of hydrotreating asphalt-containing petroleum feedstock by two successive stages of contacting with a catalyst, a composition containing metals of the VI and VIII groups of the periodic system of elements on a refractory carrier, including the first stage of contacting the feedstock with a catalyst, carried out in the presence of hydrogen-containing gas circulating from the second stage gas, the separation of the products of the first stage on the first vapor and first liquid phases, the release of hydrogen sulfide from the first vapor phase, to contacting of all or part of the liquid phase in the second stage, separation

products of the second stage into liquid and vapor phases, characterized in that, in order to simplify the process technology, the vapor phase released from the products of the second stage is introduced into the first stage of contact.

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