KR0175141B1 - Process for upgrading a sulphur containing feedstock - Google Patents

Abstract

Hydrocarbons boiling substantially in the gasoline range consisting of applying crude oil to the reforming stage and subsequently to the hydrotreatment stage and recovering substantially boiling products from the gasoline range with increased aromaticity and reduced sulfur content therefrom. A method for improving a sulfur-containing crude oil comprising a mixture.

Description

Method for improving sulfur-containing crude oil

The present invention relates to a process for improving sulfur-containing crude oil and in particular to improving the quality of crude oil comprising hydrocarbons boiling within the gasoline range, obtained by catalytic cracking.

The gasoline obtained by catalytic cracking has to be processed further until it can meet today's strong demand for high octane and low sulfur content.

Thus, the catalytically cracked gasoline has a relatively high olefin content and a low aromatic content, and an inadequate high sulfur content if there was no initial treatment of the crude oil. Quality improvement can be effected, for example, by catalytic reforming together with platinum-containing reforming catalysts. However, the presence of sulfur and nitrogen-containing compounds in the reformate crude oil reduces the performance of the catalyst and therefore it is considered necessary to remove these compounds by catalytic hydrotreatment prior to reforming to maintain sufficient catalyst life. As a result, the cost is increased.

Surprisingly, the two-stages of ineligible high content of sulfur and of boiling (mixed) crude oil substantially within the gasoline range apply sulfur-containing crude oil first to a specific reforming stage and subsequently to a hydrotreating stage. The method has been found to be very attractive for aromatics and sulfur contents.

Thus, the present invention is a gasoline range consisting of applying crude oil to a hydrotreatment stage subsequent to a reforming stage, from which the product is substantially boiled within the gasoline range and recovers products with increased aromaticity and reduced sulfur content. A method for improving sulfur-containing crude oil, including hydrocarbon mixtures substantially boiling therein.

It has also been found in the present invention that hydrotreating can be carried out in conditions that are much milder than conventional for obtaining good quality products that boil substantially within the gasoline range. As a result, the present invention provides an attractive new method (less complex) that can be suitably implemented as a whole under milder conditions. Furthermore, in the process according to the invention a high yield of liquid product can be obtained while at the same time hydrotreating is more advantageously controlled and adjustable.

It can also be obtained by other decomposition methods such as pyrolysis, delayed coking, visbreaking and flexicoliing, but substantially boiling within the gasoline range that can be obtained by catalytic cracking. Preference is given to using hydrocarbon mixtures. Such gasoline crude oils typically contain inadequate amounts of sulfur, usually at least 50 PPmw, often at least 100 ppmw or even at least 500 ppmw.

Other suitable crude oils which can be processed according to the invention are a significant amount of naphthene-containing hydrocarbon mixtures, for example petroleum naphtha, or mixtures of hydrocarbon materials with a considerable amount of naphthene-containing hydrocarbon materials which can be derived by cracking processes. .

The crude oil to be processed is suitably obtained by applying catalytic cracking, usually fluid catalytic cracking of heavy hydrocarbon oils such as vacuum gas oils, flash distillates, long residues, deasphalted vacuum residues and mixtures thereof. . Fluid catalytic cracking on a commercial scale is usually carried out in a series of processes using a batch consisting of a catalytic reactor and a catalytic reactor arranged substantially vertically. The oil to be decomposed is contacted with a hot regeneration catalyst from the regenerator. The mixture of oil and catalyst is passed upward through the reactor portion. Placing coke on the catalyst in the reactor section results in catalyst deactivation. The inactivated catalyst was separated from the product and stripped and then transferred to the regenerator. The decomposed product is classified into light oil, gasoline oil and various heavy oils, former light cycle oils, heavy cycle oils and slurry oils having a high content of C ₃ -C ₄ olefins.

Sulfur-containing crude oil will generally be composed of fractions which boil substantially in the gasoline range, ie substantially in the C ₄ -220 ° C range. However, other light constituents that benefit from aromatization can be included in the crude oil and can be processed with it in the reforming stage, for example normally gaseous olefins and / or such as C _2-4 olefins and / or C ₇ paraffins. It is a mixture containing a significant amount of paraffin.

While sufficient gasoline boiling range fraction from the cracking reactor can be included in the crude oil, it will be preferable to use fractions boiling substantially in the range 70-220 ° C., preferably 70-180 ° C., as the hydrocarbon mixture. In addition, the sulfur-containing crude oil consists essentially of a hydrocarbon mixture that substantially boils in the gasoline range.

Sulfur-containing crude oils comprising hydrocarbon mixtures substantially boiling in the range from 140 to 220 ° C., preferably in the range from 160 to 220 ° C., can be advantageously processed in the hydrotreating step together with the product obtained from the reforming step. Suitably, the sulfur-containing crude oil (contact) cracking process comprising a hydrocarbon mixture substantially boiling in the gasoline range can be derived. Suitably, additional hydrogen can be processed in the hydrotreatment stage with the product obtained from the reforming stage.

Although not preferred, it will be understood that some of the effluent from the reforming step may be separated off.

In the reforming step, it has been found that suitable catalysts for increasing the aromatics content of the crude oil, such as stable (sulfur tolerant) metal-containing crystalline silicates that exhibit high specificity for aromatization, can be used suitably. Suitably, in the reforming step, a catalyst is used that performs at least 50% of the olefins and / or naphthenes that were initially present in the sulfur-containing crude oil.

Suitably, in the modification step, the metal (M) of the X-ray diffraction pattern with four strong lines at the interplanar spacing (d) of 11.1 ± 0.2, 10.0 ± 0.2, 3.84 ± 0.07 and 3.72 ± 0.06, denoted by Å A catalyst comprising a crystalline silicate containing, wherein M is at least one Al. Fe, Ga, W, Mo or Zn.

The metal (M) may be incorporated in the matrix of zeolites or present in the pores of the catalyst. The metal is preferably present in the pores of the catalyst.

The X-ray data cited above can be obtained by Cu Kα X-ray diffraction known in the art.

Preferably, the catalyst used in the reforming step comprises metal containing crystalline silicates such as, for example, ZSM-5, crystalline iron-containing crystalline (alumino) silicates or crystalline metallosilicates with X-ray diffraction patterns as mentioned above. do.

Suitably the catalyst used in the reforming step comprises crystalline aluminosilicates having a SiO ₂ / Al ₂ O ₃ molar ratio of at least 20, preferably at least 100 and an X-ray diffraction pattern as described above.

Suitable catalysts comprising iron-containing crystalline silicates may be used in the reforming step. Preference is given to iron-containing crystalline silicates having a SiO ₂ / Al ₂ O ₃ molar ratio of 25 to 1000. When the reforming step is carried out using iron-containing crystalline aluminosilicates, the catalyst preferably has a molar ratio of SiO ₂ / Fe ₂ O ₃ of 25 to 1000 and a SiO ₂ / Al ₂ O ₃ molar ratio of 20 to 2000.

Suitably, the modifying step is carried out using a catalyst as described above comprising at least one of metal Ga, Mo, W or Zn, preferably Ga. Suitably, such catalysts comprise 0.01 to 10% by weight, more preferably 0.1 to 5% by weight of the aforementioned metals.

The reforming step also has a Si / M molar ratio of 25 to 250, wherein M is at least one of metal Ga, Mo, W or Zn, preferably using a catalyst comprising a metal-containing crystalline silicate, which is Ga Can be executed as appropriate.

Metal-containing crystalline silicates are prepared by methods known in the art, such as the following compounds: one or more alkali metal compounds, one or more organic nitrogen compounds (RN) containing organic cations, wherein the organic cations are formed in the preparation of the silicates ), And may be prepared from an aqueous solution containing at least one silicone compound and at least one aluminum compound. Preparation is carried out by keeping the mixture at high temperature until a silicate is formed and then separating the silicate crystals from the mother liquor, washing, drying and calcining the crystals.

There is a synthetic synthetic route for making these zeolite crystals. Extensive research in R.M. This can be found in Barrer's Hydrothermal Chenustry of Zeolites (Academic Press, New York, 1982).

The metallurgical-containing silicates produced often contain alkali metal ions. By suitable exchange techniques they can be replaced by other cations such as hydrogen or ammonium ions. The metal-containing crystalline silicates used in the process according to the invention preferably have an alkali metal content of less than 0.05% by weight. In the process according to the invention the metal-containing crystalline silicates can be used as such or in combination with an inert binding material such as kaolin or bentonite.

The metal can be incorporated by known techniques, for example by impregnation and ion-exchange. The metal is preferably introduced after crystallization of the silicate, for example by post impregnation.

Suitably, an alumina-containing catalyst, such as a silica-alunah containing catalyst having both desulfurization and denitrification activity, is used in the hydrotreating step. Preferably, a metal-containing alumina catalyst is used in the hydrotreating step, whereby the metal is at least one of VIB and / or Group VIII metals, preferably at least one of metals Ni, Co or Mo.

Catalysts which can be suitably used in the hydrotreating step include commercially available catalysts and can be prepared by methods known in the art.

In the process according to the invention the reforming step can be suitably carried out at a temperature of 350 to 600 ℃, a pressure of 1 to 40 bar, a space velocity of 0.5 to 10 g / g / h, the hydrotreating step is 230 to 370 ℃ Can be suitably carried out at a temperature of, a partial pressure of hydrogen of 2 to 30 bar and a space velocity of 0.5 to 15 g / g / h. Preferably, the reforming step is carried out at a temperature of 400 to 550 ° C., a pressure of 10 to 30 bar and a space velocity of 0.5 to 5 g / g / h and the hydrotreating step is a temperature of 250 to 350 ° C., 3 to 15 bar. Hydrogen partial pressure and a space velocity of 2.0 to 10 g / g / h.

The process according to the invention can be carried out using a series of reactor or stack-bed forms. Preference is given to using a series of reactors containing each catalyst. It will be appreciated that the catalyst used in the reforming step can be applied for regeneration, preferably for semi-continuous regeneration.

Preferred gasoline boiling range products of reduced sulfur content and increased aromatics can be recovered by any suitable method, typically fractionation.

The present invention will now be illustrated by the following examples.

Example 1

a) Compositions of Catalysts A and B.

Reforming catalyst A comprises a commercially available ZSM-5 type crystalline zeolite having a SiO ₂ / Al ₂ O ₃ molar ratio of 250 and containing 130 ppm Na. Catalyst A is ion exchanged with gallium in its H ⁺ type as follows:

80 g of zeolite was refluxed for 1 hour in a 0.05 M solution of potassium nitrate. The sample was washed with distilled water, dried (120 ° C., 16 hours) and calcined at 540 ° C. for 2 hours.

The resulting gallium-containing aluminosilicate contained 1% by weight gallium. Hydrotreating catalyst B comprised 84.1 wt% amorphous alumina, 2.7 wt% nickel and 13.2 wt% molybdenum.

b) Catalysts A and B were subjected to 25 hours in the experiments carried out according to the invention. Catalyst B was first presulfurized. As raw material oil, catalytically cracked gasoline having the following properties was used.

The operating conditions under which the experiment was performed and the results obtained are shown in Table 1 below.

Claims (15)

Sulfur-containing crude oil is subjected to a reforming step and then to a hydrotreatment step, from which substantially recover within the gasoline range, consisting of recovering products having substantially boiling and increased aromaticity and reduced sulfur content in the gasoline range. A method for improving a sulfur-containing crude oil comprising a hydrocarbon mixture which is boiled into a furnace, the reforming step of which is represented by 10 ^-10 m (Å) of 11.1 ± 0.2, 10.0 ± 0.2, 3.84 ± 0.07 and 3.72 ± 0.06 A catalyst comprising a metal (M) -containing crystalline silicate in an X-ray diffraction pattern having four strong lines at the interplanar spacing (d) is applied, where M is Al, Fe, Ga, W, Mo or Zn and of at least one metal (M) - containing crystalline silicate is 20 or more SiO ₂ / Al ₂ O or a crystalline aluminosilicate having a _three molar ratios, or the alumina is present in the SiO ₂ / Al ₂ O ₃ molar ratio of 20 to 2000 25 If iron having 1000 of SiO ₂ / Fe ₂ O ₃ molar ratio-containing crystalline (alumino) silicate method. The method of claim 1 wherein a hydrocarbon mixture derived from the decomposition process is used. The process of claim 1, wherein the hydrocarbon mixture is an oil that substantially boils in the range of 70 to 220 ° C. 3. The process of claim 1 wherein the crude oil consists essentially of a hydrocarbon mixture that substantially boils in the gasoline range. The process of claim 1 wherein the crude oil comprises at least 50 ppmw of sulfur. The process of claim 1 wherein the sulfur-containing crude oil comprising hydrocarbon mixture substantially boiling in the range of 140 to 220 ° C. is processed in a hydrotreating step together with the product obtained from the reforming step. The process of claim 1 wherein additional hydrogen is processed in the hydrotreating step with the product obtained from the reforming step. The process of claim 1 wherein the hydrocarbon mixture comprising a substantial amount of C _2-4 olefins and / or C ₇ paraffins is processed in the reforming step together with the crude oil. The process of claim 1, wherein the catalyst comprising 0.01 to% by weight of at least one of Ga, W, Mo, or Zn is subjected to a reforming step. The process of claim 1, wherein the catalyst comprises a metal-containing crystalline silicate having a molar ratio of Si / M of 25 to 250, wherein M is at least one of Ga, Mo, W or Zn. The method of claim 1 wherein the metal comprises Ga. The process of claim 1 wherein the alumina-containing catalyst is subjected to a hydrotreatment step. The method of claim 12, wherein the metal containing catalyst is subjected to a hydrotreatment step, wherein the metal is at least one of Group VIB or Group Vlll metals. The method of claim 13, wherein the metal is one or more of Ni, Mo, or Co. The process of claim 1, wherein the reforming step is carried out at a temperature of 350 to 600 ° C., a pressure of 1 to 40 bar and a space velocity of 0.5 to 10 g / g / h. The process is carried out at 230 to 370 ° C., hydrogen partial pressure of 2 to 30 bar and space velocity of 0.5 to 15 g / g / h.