CS201289B1 - Method of hydropurification of hydrocarbons mixtures - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to the hydrotreating of hydrocarbon mixtures having a boiling point of 30 to 360 ° C containing sulfur, oxygen and nitrogen compounds on a cobalt-molybdenum catalyst which has been put into a highly active hydrocarbon form prior to contact with hydrocarbons. conditions.

Hydrocarbon mixtures obtained by distillation of crude oil or other raw materials are raw materials for the production of liquid fuels and for petrochemical purposes. Depending on the type of crude oil, they have certain concentrations of mime, oxygen and nitrogen compounds, and possibly unsaturated compounds. These compounds must not be present in the finished products and are also detrimental to various subsequent catalytic processes, in particular catalytic reforming. In recent years, especially sulfur-sensitive reforming novel catalysts have arisen, requiring its content to be limited to a concentration of 1 ppm in the hydrotreating product. In the case of heavier fractions, it is also necessary to remove mainly sulfur and thereby reduce combustion emissions.

Hydrogen refining is the most convenient way to remove impurities, and the process has been refined for decades to increase efficiency and maximize efficiency. The most common catalyst is undoubtedly the capsule-moly currency catalyst on active alumina. The system of the two metals has a significantly higher activity than each of the metals separately. The hydrotreating conditions become stricter over time, reducing the pressure, temperature and amount of catalyst. Also, the theoretical knowledge of the catalytic system is being completed and the limits of the existence of sulfides, oxides, or metals themselves are set, and relations to the catalytic activity are also clarified. Modern cobalt-molybdenum catalysts have been put into action by various processes which lead to increasingly improved activity and stability. The procedures are based on oxidic compounds and their conversion to the active simic form by the action of various simile reagents and under different conditions. Until recently, the usual procedure was gradual reduction, sulphurization and hydrogenation refining itself. The catalyst was heated at a high pressure of 3.0 to 30 MPa with hydrogen at temperatures above 300 and possibly above 400 ° C and then sulfurized at these temperatures by various methods. The result was a well-active catalyst capable of removing non-hydrocarbon impurities to a desired level at that time. However, due to the low sulfur values in the product, the process was not sufficiently suitable and further catalysts were deactivated during the treatment of the incompletely desulfurized product.

The invention relates to the hydrotreating of hydrocarbon mixtures boiling in the range of 30 to 360, preferably 30 and 200 ° C, containing organic sulfur, oxygen and nitrogen compounds, optionally also unsaturated, on cobalt-molyibden catalysts on alumina. SUMMARY OF THE INVENTION The present invention consists in heating hydrocarbon mixtures with hydrogen and hydrogen sulphide at a temperature of 250 to 350 ° C at 1.0 to 5.0 MPa and contacting them with a catalyst comprising an active system of 1 to 5% cobalt sulfides and 8 to 15% of molybdenum sulfides on active alumina, formed by heating a cobalt-molyphodene catalyst with hydrogen gas at 0.2 to 5.0 MPa containing 0.01 to 10% by volume of hydrogen sulfide, from normal temperature to 250 to 350 ° C with a time lag of 200 to 250 ° C to 600 hours, optionally adding 1 to 5000 ppm of carbon disulphide, organic sulfides or mercaptans to the incoming gas, giving 5 to 1000 volumes per volume catalyst per hour.

The improved refinery hydrogenation is then carried out in the presence of the catalyst system of the invention and the contaminated hydrocarbon mixture with hydrogen and hydrogen sulphide is heated to a temperature of 250 to 350 ° C at 1.0 to 5.0 MPa. The volume ratio of hydrogen to phio hydrogen is 20 to 500 in the reaction. The gas either circulates or passes through it and contains 0.01 to 10% by volume of hydrogen sulfide. The volume ratio between the hydrocarbons and the catalyst is 1 to 10 per hour.

Preferably, the contaminated hydrocarbon, hydrogen and hydrogen sulfide contact with the catalyst begins at a temperature of 280 to 320 ° C and the catalyst does not come into contact with hydrogen at a temperature above 150 to 180 ° C at any stage of activation or working period.

By analyzing the conditions of the process of the invention, those skilled in the art of hydrotreating will recognize the advantages of the new process. This provides a stable cobalt and molybdenum sulfide system on active alumina by the simplest means available in refineries. The range of activation temperatures, pressures and ratios of hydrogen to hydrogen sulfide or sim compounds guarantee the formation of Co ₉ Sg and MoS ₂ on the active surface of gamma alumina. There is no difference in the activation of the original oxide systems, whether they were prepared in any way, by co-precipitation or saturation, or in other ways. The active sulfide system operates on both the wide-porous and narrow-porous carrier systems, with improvements being made to the less preferred porous system. The process according to the invention provides the conditions necessary to achieve a sustained active state of sulfides, which is the basis of the high activity and at the same time the low coke formation.

Advantageously marked conditions of activation of the catalytic system as well as the actual hydrogenation refining are found optimum, but always feasible in practical refining units. In particular, it is necessary to criticize the pressure and temperature as well as the hydrogen sulfide concentration during propagation and the temperature of the hydrogenation refining itself.

The process of the invention, although rather broad at some points, is not recommended for other catalytic hydrotreating systems and especially not for systems containing tungsten and nickel or combinations thereof with molybdenum and cobalt, nor are the oil fractions above 360 ° C suitable as hydrogenation feedstocks. refining. These systems have other specificities and cannot be included in the invention without exception. It follows that the process according to the invention relates only to the hydrotreating of gasoline and intermediate fractions on a cobalt-molybdenum catalyst and that it brings a significant improvement in this refining region.

In the example below, two comparison procedures are included, one usually performed in a refinery and one of the modifications of the invention. However, the scope of the modification does not limit the scope of the invention.

Example

In a refinery unit handling 90-170 ° C of naphtha containing 250 ppm of sulfur at 3.5 MPa, v / v at 4 v / v. Cat. h., and a gas to feed volume ratio of 300: 1, desulfurization at 360 ° C to 2 to 5 ppm in the product was achieved. In the subsequent reforming unit, a concentration of 8 to 20 mg / m ^{3 of} circulating gas was generated from the residual sulfur.

Cobalt-molybdenum catalyst containing

3.5% CoO and 12% MoO ₃ on active gamma alumina was activated by heating with pure hydrogen at 410 ° C, and then a gas containing 500-1000 mg H ₂ S / m ³ was added and heated for 24-48 hours. After the temperatures were reduced to 360 ° C, contact with the reforming gasoline was initiated.

In the second unit, also pre-catalytic reforming, the same oxide catalyst was heated under a pressure of 2.5 MPa from a normal temperature to 220 ° C with a hydrogen gas containing 500 mg hydrogen sulfide / m ³ . After a delay in which the hydrogen sulphide content equalized before and after the catalyst, it was heated to 260 ° C in the presence of the same gas when contact with the heavy gasoline content was initiated. 250 ppm

WITH.

After the temperature was raised to 310 ° C, at a pressure of 3.5 MPa and a velocity of 4 h ¹ , the desulfurization consistently reached below 1 ppm of sulfur in the product, resulting in a hydrogen sulfide content of the reforming unit gas below 2 ppm by volume.

In the table, the two procedures are compared.

Table

Comparison of refining hydrogenation procedures

method usual according to invention S in product (ppm) 2 to 5 under 1 H ₂ S in reform. gas (mg / m ³ ) 8 to 20 under 2 reaction temperature ° C 360 310

In the laboratory, the Co-Mo-oxide catalyst was sulphurized according to both processes and it was found that the catalyst not activated according to the invention contained 0.8% by weight. more sulfur, which corresponds to the presence of imperfectly cobalt. Example 2

In a quarter-stage apparatus, gasoline having a boiling point of 80-170 ° C containing 200 ppm S was hydrogenated.

Two parallel procedures were performed. The first was carried out according to the invention and the second the current process used in industrial units.

After spraying, the temperature gradually increased from 300 to 375 ° C and the following results were achieved:

Method AND (B) With ppm at 300 ° C 11 43 325 ° C 7 29 350 ° C 5 12 mp 375 ° C 4 8

Conditions:

Try AND (B) according to invention ordinary pressure MPa 1.0 3.0 Sulfur from ° C 30 410 to ° C 220 420 Sulfur gas% by volume H ₂ S 1 1 % vol H ₂ 90 90 injection temperature (° C) 280 280

SUBJECT OF THE INVENTION

Claims (3)

Process for the hydrotreating of hydrocarbon mixtures having a boiling point of 30 to 360 ° C, preferably 30 to 200 ° C, containing organic sulfur, oxygen and nitrogen compounds, optionally also unsaturated compounds, on cobalt-molybdenum catalysts on alumina, characterized in that the hydrocarbon mixtures with hydrogen and hydrogen sulphide are heated to a temperature of 250 to 350 ° C at 1.0 to 5.0 MPa and are contacted with a catalyst containing an active system of 1 to 5% cobalt sulfides and 8 to 15% molybdenum sulfides to active alumina, formed by heating a cobalt-molybdenum oxide catalyst with a hydrogen gas at 0.2 to 5.0 MPa, containing 0.01 to 10% by volume of hydrogen sulfide, from normal temperature to 250 to 350 ° C with a dwell between 200 and 250 DEG C. for 2 to 60 hours, optionally adding in excess of 5 to 5 ppm of carbon disulphide, organic sulphides or mercaptans to the inlet gas supplied at 5 and 1000 volumes per volume of catalyst in the reaction space per hour. 2. The process of claim 1 wherein the ratio of hydrocarbons to catalyst is from about 1 to about 10 volumes per volume per hour and the hydrocarbon to hydrogen ratio is from about 20 volumes to about 500 volumes per volume, wherein the gas is circulated or flowed through the passage. up to 10% H ₂ S by volume 3. The process of claim 1 wherein the hydrocarbons, hydrogen and hydrogen sulfide are contacted with the catalyst at an initial temperature of 280 to 320 [deg.] C and the catalyst is contacted only with hydrogen at temperatures of not more than 150 to 180 [deg.] C. .