DE1770035A1 - Process for the use and processing of sulfur-rich heavy fractions - Google Patents

Description

Process for the use and processing of sulfur-rich heavy oil fractions The invention relates to a method for the use and processing of sulfur-rich Heavy oil fractions. It also relates to a process in which a heavy oil fraction with at least 1% by weight of sulfur is separated into two practicals, each for itself be worked up and used in an extremely advantageous and effective manner can, with the work-up methods of the two practicals in particularly advantageous Way are coupled.

Common petroleum refining methods start with crude fractionation, the lighter and more valuable components separated from the crude oil. All or part of the heavy residues from this fractionation is usually sold as cheaper Helzöl. Depending on the intended use, these are The practical uses of heating oils are limited. For example, in certain compact boilers, certain metallurgical oils and in large diesel engines and gas turbines, ash-forming metals and slow-burning asphalts are undesirable and in any event, a high sulfur content is undesirable, particularly in view of the fact that it is undesirable due to public concerns and official regulations In terms of air pollution, sulfur-containing heating oils are increasingly less demanded by the market. The still permitted sulfur content depends on the local situation away. For example, heating oils with more al. 0.5% sulfur in Los Angeles County / USA Don't be burned and as of April 1971 you're burning more than 1.0% sulfur containing heating oils is banned in New York City. That from the burning of sulfur-safe Heating oil-derived SO2 in the exhaust gases can be removed according to the usual known methods but these processes are not generally considered economical at the moment held justified. The economic importance of low-sulfur fuels therefore increases. And in the rushes where the heating oil is directly in sensitive plants, e.g. in compact boilers, gas turbines every diesel engine is used fuels with a low content of metals and asphaltenes are important practical and economic benefits.

Because of the expanded market for gasoline, jet fuel, desulphurized Heating oil and other light products, the refining industry is looking for methods for Refining an expanded fraction of crude oil to add more of the bottom fraction to be able to convert. Because there are more sulfur, metals and asphaltenes in these soil fractions must contain processes for the removal of these materials before the catalytic Treatments are applied. It is known that heavy oils hydrodesulfurization catalysts coke quickly and increase hydrogen consumption; most separation processes however, pollute the products, especially the distillation residue heating oil only compete with other porms for heating energy and with electrically generated energy If the price is low, it can result in too much additional costs.

It is therefore an object of the present invention to provide a method for Specify the use and processing of sulfur-rich heavy oil fractions in which the coupled. Procedural stages bring the necessary advantages with sioh to the To make procedures attractive.

The inventive method consists essentially in that the heavy oil is divided into a low-sulfur fraction that makes up the greater part of the oil with a low content of asphaltenes and metals and a sulfur-rich one Separates the fraction with a high asphaltene content that makes up a small part of the oil. the Impurity-free fraction is wholly or partially in the presence of a Katalyeators hydrodesulfurized and as quality heating oil or as a cracking raw material (cat oracking stock) or isolated for both purposes. The contaminated fraction is used as fuel for certain industrial furnaces or industrial power stations are used. The exhaust from the Combustion of this fraction has a relatively high concentration of 802. That 502 becomes with the H2S from the hydrodesulfurization process with the formation of elemental Sulfur reacted, the exhaust gas being desulfurized and a pollution of the air with sulfur oxide is avoided. The sulfur turns 51.

By-product sold or e.g. for the production of sulfuric acid used for fertilizers or other purposes.

Alternatively, the sulfur obtained can also be used in industrial furnaces or power plants be incinerated, its heat of combustion being usefully recovered is, and the SO2 formed can from the Abges In a signed manner according to the Burn will be removed. It needs to be highlighted. that is the final distance of Sulfur from the combustion system in the flue gas desulfurization device he follows. The economy of exhaust gas desulphurisation devices depends on TOD Sulfur content of the exhaust gas. The cost of desulfurization depends very much on the volume of the exhaust gas to be treated and only to a small extent from it Sulfur content, but the profit from the by-product is direct proportional to the sulfur content. The xetto costs for the desulphurisation of the exhaust gas are therefore lower, the higher the sulfur content. A particular advantage of the process of the invention is the high concentration of sulfur in the flue gas desulfurization zone and the associated improved economy of the exhaust gas desulfurization device self.

The invention is illustrated using the attached drawing, which shows a flow diagram represents in one embodiment of the method of the invention, explained in more detail, The sulfur-rich heavy oil feed is fed through line 2 to the extraction zone 1 introduced. Suitable feeds are e.g. heavy residue fractions or Soil fractions from the original separation of the lighter and more valuable fractions of the heavy and less valuable fractions of crude oil. The heavy one Has petroleum oil an initial boiling point of 204 to 593 ° C depending on the properties of the original crude oil and the way in which it was processed. The feed usually contains 1 to 12 total sulfur, 2 to 30% by weight asphaltenes, 10 to 10,000 ppm metals and optionally nitrogen compounds, areneik, ash or other catalyst impurities. Typical suitable loads are e.g. Residues from atmospheric distillation, residues from vacuum distillation, crushed soil fractions, (visbreaker bottoms thermal cracked bottom fractions, cyclization fractions, slate bl and mixtures thereof. These fractions usually contain 1.5 to 6% by weight Sulfur In the extraction zone, the feed is countercurrent to a selective Solvent contacted, which is fed via line 3, Suitable solvents are e.g. BP, BF3, HF-BF3 complexes, phenols, propane, butane, pentane, heptane, hexane, Naphtha and mixtures of C2 to C [paraffinic hydrocarbons. Suitable extraction conditions are e.g. pressures from 0.35 to 14.1 kg / cm2 and temperatures from -6.7 to 260 ° C. It earth ratios of solvent su O1 of 1: 5 to 5: 1 are used. The extraction is carried out in the usual known manner with conventional contact devices. The solvent extract is soldered upside down. device 4 led to the scraper 5 and the withdrawn solvent is via lines 6 and 3 into the extraction zone recycled. The solvent-free oil is fed into the hydrodesulfurization zone 8 via line 7 and according to market requirements, a part can be sent via line 23 deducted for certain purposes, e.g. for use in large Gas turbines or diesel engines in ocean-going vessels or in places where the low Sulfur content appears acceptable in terms of air pollution. The soil fraction from the extraction zone, via line 9, the large industrial boiler or the Power plant 10 supplied.

For example, if a feed containing 3% sulfur and about 5% by weight asphaltenes, and a solvent such as pentane is used the overhead fraction comprises about 95% of the feed and contains about 2.5 gb sulfur and the soil fraction excreted by the solvent is very viscous and contains practically all of the asphaltenes and metal and 6 to 8% by weight sulfur. These Soil fraction as such is usually unsuitable as fuel and must be ridden Distillate to reduce viscosity $ can be diluted in order to be shipped to the consumer can be and the content of sulfur, metals and asphaltenes to an acceptable level Redux values n. Debtillet is relatively expensive and its use for di @@ en purposes represents an economic burden. In the method of the invention, this must Fuel but not with distillate be diluted what a further essential economic benefit. Because the heating oil is not shipped must be, the Yiskosttät does not matter.

And in a suitably operated large industrial fan or one Kraftanlage, where, unlike others, may be discontinuous in smaller scale systems. the combustion process is carefully monitored can be, the kinfluences of asphaltenes and metals can be more satisfactory Way to be controlled while the sulfur through the exhaust desulphurisation device is mastered. In this way distillate is used as a mere dilution agent avoided and the deotillate saved for more valuable uses.

Except for the above-mentioned solvent extraction treatment as Separation method, there are also various other separation methods for splitting the carbonic acid into a relatively low-sulfur fraction, which makes up 50 to 95% by volume of the Schiokung, and in a relatively schwetelrelcho fraction, which is 5 to 50% by volume of the charge matters, suitable. For example, vacuum distillation of the so-called "Middle East topped "crude oil are used, with a split of the fraction in proportion. of about 50:50 is obtained. If so desired, the separation is complete in one crude heavy oil effected by distillation will9 where one or several slight distillation fractions, z03. Gas, gasoli, n, kerosene, @eichtes Fuel oil and two sulfur-containing fractions obtained by the process of the invention Can be worked up, can be recovered Furthermore, residues from a atmospheric or vacuum distillation according to a conventionally known method be coked and the coke can be used as fuel in the industrial furnace or the power plant as well as coal can be used. The thermal ones used in coking Translations do not selectively remove sulfur from the high boiling fractions. Since the sulfur content of the coke is higher than that of the overhead fraction, it is also the sulfur content of the high-boiling oil from the asphaltene removal is greater than that of the overhead fraction. According to a preferred embodiment of the invention a petroleum residues fraction to be used as heating oil and more contains than 1% sulfur, in a fraction for processing and for use as a quality heating oil with a lower sulfur content than the starting material and in a residual fraction with a higher sulfur content than the starting material, that forms an exhaust gas that has to be treated to remove SO2, split, With reference to the attached drawing, the procedure is followed so that the relatively low in sulfur, i.e. you about Containing 0.5 to 3.5 wt.% S Oil from the separation stage in the hydrodesulfurization zone 8 in the usual manner with known ones Treated catalysts. The desulphurized product is withdrawn via line 11. Suitable process conditions are: feed rate, v / v / hour. 0.2 up to 3.0 hydrogen rate, 1 / m3 86 500 - 10 380 000 (500 - 6000 SCF / Bb1.) pressure, atm 21-211 temperature, ° C 288-454 Preferred catalysts are 5 to 15% by weight of xolybdenum oxide on porous aluminum tomoxide and mixtures of cobalt oxide (3 to 6% by weight) with molybdenum oxide (6 to 12 wt.%) On adsorption aluminum oxide. Catalysts containing nickel, chromium, Platinum and tungsten in the form of metals, oxides or sulphides, either alone or in combination with cobalt and / or molybdenum, applied to aluminum oxide, Aluminum oxide stabilized with silicon oxide, adsorption carbon, kieselguhr and Bauxite, can also be used.

A H2 and H2S containing gas is overhead from zone 8 over Line 12 withdrawn and the H2 @ is removed using a conventional gas separation device 13 removed. Of the Hydrogen is recycled via lines 14 and 7.

H2S is recycled via line 15 for later reuse in the process the invention dissipated.

The relatively sulfur-rich fraction, which is 5 to 50% by volume of the feed and has a high percentage of sulfur, i.e. about 2.5 to 10 wt.% S, as well as the main amount of catalyst impurities, is via line 9 passed to power plant 10 for combustion in a furnace.

If the material is a solid, e.g. outside of the coking reaction, represents, it can be fed to the furnace and put into dieeen according to one of the usual known methods Methods are introduced. The material can also be mixed with other fuel oils or crushed solid fuels, e.g. B. coal supplied through line 16, mixed will. The combustion process of the power plant 10 is conventional and well known Weiae carried out. Air for combustion is fed in via line 17.

An exhaust gas with a relatively high concentration of SO2 becomes according to one embodiment According to the invention, the exhaust gas with H2S from line 15 at a temperature in the range from 93 to 149 0C mixed with formation of sulfur and water. The implementation is usually used in counter wait for a catalyst or a solid adsorptive agent, e.g. aluminum oxide. The sulfur will removed from the catalyst by heating to 485 ° C to evaporate the sulfur. This implementation is known and details about it can be found in the literature e.g. Doumani et al., Ind. Eng. Chem., Volume 36, April 1944, pp 329-332, and Gamson et al, Chem. Eng. Progress, Volume 49, April 1953, pages 203-215.

In the accompanying drawing, line 20 represents a line, the vaporized sulfur or located on a catalyst or adsorbent Sulfur from the sulfur recovery zone 21 is fed. Line 24 gives a line to remove the sulfur formed. Line 22 means the return line for the catalyst or adsorbent.

In a further embodiment of the invention, H2S is used 15 and the broken line 15A are supplied to the power plant fuel supply line and passed into the power analog 10 as fuel. The H2S is formed with the formation of S02 and water burned. The exhaust gas containing an increased amount of SO2 is after desulphurized using the best and most suitable method. Suitable. Procedure and e.B. the so-called Alkalieed Alumina "method of the U.S. Bureau of one, or the" clean air "method or the catalytic oxidation process (see e.g. Journal of the Air Pollution Control Association, Volume 15, No. 10, pp. 459-464 (1965) ) or other commonly known procedures. The exact nature of the sulphurous By-product depends of course on the process chosen.

The following example describes an embodiment of the invention, which is similar to the one shown in the flowchart, with the exception that the one at the beginning Separation stage no solvent extraction, but a vacuum distillation applied will.

Example 1 8170 m3 / day residues from atmospheric distillation of Venezuela oil with 2.85% sulfur, 10.5% asphaltenes and 475 ppm by weight (wppm) metals, mainly vanadium, were vacuum distilled, with 4450 m3 / day distillate with 1.98% sulfur, 0.3% asphaltenes and 3 weight ppm metals and 3750 m3 / day vacuum soil fraction with 3.56% sulfur, 22.7% asphaltenes and 105G weight ppi metals. The distillate was purified using cobalt molybnate on alumina ale catalyst at 56.2 atil, 3710C, a hydrogen recycle gas rate of 433000 1 / m3 (2500 SCF / bb1) and at a space velocity of 1.0 V / V / hr. hydrodesulfurized. The sulfur content is reduced from 1.98% to 0.19% and the H2Sw formed, which makes up 2.12% sulfur, based on the vacuum soil fraction, is used in the exhaust gas desulphurisation stage or added to the fuel for the power plant. The amount of sulfur that is fed to the exhaust gas desulphurization stage is therefore 5.58%, based on the vacuum bottom fraction. If this H2S is fed directly to the exhaust gas desulphurization, it is desirable to carry out the so-called Claus reaction between SO2 and H2S, in which sulfur is formed according to the following equation: 2 H2S + SO2 # 2 H20 + 3S. As a rule, about 3% of the sulfur oxides contained in the exhaust gas are SO3 and about 97% are SO2. The SO3 reacts in the same way, but more H2S is needed to meet the stoichiometric requirements: In total, 2.03 moles of H2S per mole (S02 + S05) of the exhaust gas are required. In the present example, the exhaust gas contained 3.56% by weight of sulfur as (SO2 + S03) in a concentration of about 2000 ppm by weight as (SO2 + S03) depending on the amount of excess air that was used during the combustion So 3.56 z 2.03 = 7.24% sulfur in the form of H2S, based on the vacuum soil fraction, required to convert the total amount (SO2 + S03). In this example, part of the required H2B. namely 5.12, based on vacuum residual (ie 7.24-2.12%) supplied from the outside by converting part of the sulfur recovered at the end with hydrogen. The amount of H2S that needs to be produced depends on the sulfur content in the distillate and the bottoms fractions. In certain cases, e.g. when removing asphaltenes or coking, where the overhead fraction is large compared to the bottom fraction, no additional H2S is needed and in these cases the H28 formed during desulphurisation is split up and part of it directly into the desulphurisation exhaust gas and the rest fed to the combustion gases, but in such a ratio that the required etochio in the exhaust gas desulphurisation. metric equilibrium exists.

In this example, all of the H2S can be burned in the furnace, if the exhaust gas desulphurisation process is based on other principles than the Claus reaction. In this Palle the exhaust gas of solids is in Purified in a conventional manner and then cleaned at about 4540C over a standard vanadium SO2 oxidation catalyst to transfer 95% of the SO2 into SO3.

With continued cooling of the exhaust gas to 104 ° C condensed diluted 75% sulfuric acid, with most of the sulfur oxides being removed from the exhaust gas will. The 75% sulfuric acid is reduced to 93%, a commercially used one Standard concentration, concentrated and used for fertilizers and other purposes. The sulfuric acid obtained is 680 tons / day. For example, at a price of around DM 100 / ton: means this income of DM 68000, - / day or about DII 18.3 / m3 soil fraction fed to the furnace and thus contributes to the cost recovery of the entire desulfurization and the heating oil improvement according to the method of the invention.

By combining the individual process steps of the invention Processed becomes an effective and economical basis for the processing of High-sulfur oil fractions that are currently being traded at low prices must, created. Depending on the feed supplied to the process you got low-sulfur product a quality heating oil that is used for gas turbines, diesel engines and other sensitive energy-producing machines is suitable, or a low-sulfur one Starting material for further refining, e.g. B. to the so-called "cat-cracking" or hydrocracking. Depending on how the H2S is used, the exhaust gas can be burned the sulfur-rich fraction of elemental sulfur or H2804 or other valuable ones Commercial products are obtained.

A very important advantage of the method of the invention is formation of a pure exhaust gas that is oozed in tone Areas without the air To contaminate sulfur oxide, can be drained. In summary it can be stated that, according to the process of the invention, heavy residue hydrocarbon oils converted into quality heating oils or into fractions suitable for further refining can be generated at the same time cheap thermal energy, more valuable elementary Sulfur, sulfuric acid or other valuable sulfur-containing by-products are obtained and where an exhaust gas that does not pollute the air with sulfur oxides, going off.

Claims (11)

P a t e n t a n s p r ü c h e =============================== 1. Procedure for the use and processing of sulfur-rich heavy oil fractions with at least t% by weight of sulfur, characterized in that (A) is a sulfur-rich heavy oil fraction subjected to a separation operation in which they are divided into a relatively low-sulfur fraction, which makes up 50 to 95% by volume of the charge and is relatively high in sulfur fraction, which makes up 5 to 50% by volume of the feed, is separated, (B) the relative Low-sulfur fraction in the presence of a catalyst under hydrodesulfurization conditions hydrodesulfurized, (C) a non-sulfurized process oil and H28 isolated, (D) die relatively sulfur-rich fraction under conditions in which SO2 is formed in the exhaust gas is, burns and (E) the obtained ES and 802 with the formation of elemental sulfur converts and isolates sulfur there. 2. The method according to claim 1, characterized in that ian as Separation operations apply vacuum distillation. 3, the method according to claim 1, characterized in that as Applying coking disconnect operation. 4. The method according to claim 1, characterized in that as racing operation uses solvent extraction. 5. The method according to claim 4, characterized in that as Solvent uses a C3-cs paraffinic hydrocarbon. 6, the method according to claim 4, characterized in that ale Solvent propane used. 7. The method according to claim 4, characterized in that as Solvent used a mixture of propane and butane. 8. The method according to claim 4, characterized in that as Solvent pentane used. 9. The method according to claims 1 to 8, characterized in that one (A) a heavy residue hydrocarbon oil with at least 1 wt.% sulfur, 2 to 30% by weight of asphaltenes -a 10 to 10,000 ppa metals subjected to a separation operation, in the the oil into a first fraction with a lower sulfur content than that of the feed oil, which is 50 to 95 val of the feed oil, and into a second fraction with a higher sulfur content than that of the feed oil, which contains practically all of the asphaltenes and metal and 5 to 50% by volume of the Feed oil separates, (B) the first fraction in the presence of a sulfur sensitive Catalyst hydrodesulfurized under hydrodesulfurization conditions, (c) the obtained hydrodesulfurized quality heating oil that contains less than 1% by weight of sulfur and H2S, isolated, (D) the second fraction and the H2S obtained in the furnace of an electric power station burns with the formation of an increased amount of S02 in the exhaust gas, (E) S02 and possibly any SO3 present is removed from the exhaust gas with the aid of an absorbent, (F) from it valuable sulfur by-product is isolated and (G) the practically sulfur-free exhaust gas releases into the atmosphere. 10. The method according to claim 9, characterized in that one dus the SO2 contained in the exhaust gas is converted into SO3 and from the exhaust gas to the formation of sulfuric acid removed. 11. The method according to claim 9, characterized in that one Part of the first fraction is isolated as the product of the process and the remainder of the fraction hydrodesulfurized. Lee r s e i t e