DE1954004C - Process for the conversion and desulfurization of a hydrocarbon feed - Google Patents

Description

a) the feedstock is heated to a temperature in the range of 260 to 413 ° C,

b) the heated feed in the catalytic reaction zone at a pressure of converts more than 68 atmospheres with hydrogen,

c) the resulting reaction zone effluent in a first separation zone at approximately the same Pressure like that of the catalytic reaction zone in a first vapor phase and a first separates the liquid phase,

d) the first vapor phase in a second separation zone at approximately the same pressure as in the first separation zone and at reduced temperature into a hydrogen-rich second vapor phase and separates a second liquid phase,

e) at least part of the second vapor phase is returned to the catalytic reaction zone,

f) at least a portion of the first liquid phase in a third separation zone at about separates into a third vapor phase and a third liquid phase at the same temperature,

g) at least part of the third liquid phase in a non-catalytic thermal Reaction zone cracks,

h) the resulting cracked product effluent in a fourth separation zone at a reduced rate Pressure from 1 ata to 6.8 atü in a fourth liquid phase and a fourth vapor phase separates and

i) the fourth liquid phase in a fifth separation zone at a reduced pressure between subatmospheric pressure and 3.4 atmospheres in an asphaltic residue and at least a fifth liquid phase, the distillable hydrocarbons of reduced Contains sulfur, separates

2. The method according spoke 1, characterized in that one part of the fifth liquid Phase returns to the third liquid phase in such an amount that there is a ratio of combined feed to the thermal reaction zone results in from about 1.2: 1 to about 3: 1.

3. The method according to claim 1 or 2, characterized characterized in that one part of the first liquid phase in such an amount in the feed causes a ratio of the combined feed to the catalytic Gives reaction zone from about 1.1: 1 to about 3.5: 1

4. The method according to any one of claims 1 to 3, characterized in that part of the fifth liquid phase returned to the feed to the catalytic reaction zone

5. The method according to any one of claims 1 to 4, characterized in that holds the second separation zone at a temperature in the range of 16 to 6O ⁰ C

6. The method according to any one of claims 1 to 5, characterized in that the third separation zone at a pressure in the range of 10.2 to 23.8 atmospheres

7. The method according to any one of claims 1 to 6, characterized in that the thermal Reaction zone at a pressure in the range of 10.2 to 23.8 atmospheres and a temperature that is approximately coincides with the temperature of the third liquid phase

The invention relates to a process for converting and desulfurizing a hydrocarbon feedstock, of which at least 10% boil above 566 ° C and the one relatively low Metal content, especially less than about 150 parts per million total metals, calculated in the elemental state, but a high sulfur content, in particular more than 2.0 percent by weight, has the formation of lower-boiling distillable hydrocarbon products reduced sulfur content, at which the hydrocarbon feed after heating in a catalytic reaction zone at elevated pressure in the presence of hydrogen for removal of sulfur compounds and the production of lower-boiling hydrocarbons, the resulting Separate reaction mixture and thereby obtained liquid portions of a further cracking reaction with subsequent work-up of the reaction products are subjected.

Such oils are also called black oils because of their usually deep dark to black color Hydrocarbon feedstocks such as crude oils and especially those extracted from tar sands heavy residues, topped crude oils and vacuum residues, also contain nitrogenous compounds, asphaltic substances contained in light hydrocarbons such as pentane and / or heptane, are insoluble, and high molecular weight organometallic complexes. The metallic complexes contain nickel and vanadium as metal components. Such a material generally has a specific gravity greater than about 0.9340 at 15.6 ° C and a Conradson coke residue of generally 1.0 weight percent; a large proportion of the black oils have a Conradson coking residue above 10%. As examples for such black oils the bottoms from crude oil distillation columns may be mentioned, e.g. a

Bottom product with a specific gravity of about 0.9705 at 15.6 ° C and a content of impurities of about 3.0 weight percent sulfur, 3830 parts per million total nitrogen, 85 parts each Million total metals, about 11.0 percent by weight of insoluble asphalthenes and about 40.0 percent of non-stylable Shares.

These low-value input materials or theirs, which are constantly offered in abundance on the market High-molecular fractions can largely only be used as road asphalt or · - when diluted with higher-quality Distillate hydrocarbons — are used as extremely low-quality heating oil. It exists hence a pronounced technical interest in a useful and economical conversion of such Black oils in desulphurized lower boiling carbon hydrogen products.

The main difficulty with the previous verification methods is the lack of sulfur stability dei catalysts when the feedstock has large amounts of asphaltic substances and sulfur contains. Since the process must be carried out at such a high operational severity that simultaneously with the Conversion of sulfur-containing compounds into hydrogen sulfide and hydrocarbons a conversion Made from non-distillable fractions, the asphaltic constituents tend to be in the feedstock are dispersed to agglomeration and polymerization so that their conversion into more valuable oil products are practically excluded. Furthermore, the polymerized asphaltic complexes are deposited on the catalyst, which leads to leads to a constant increase in the deactivation rate.

Hydrocracking processes and those involved Reactions are well known (Kirk-Othmer, Encyclopedia of Chemical Technology,! Edition, Vol. 15, 1968, pp. 35 to 37). With this one Process, however, is not generally a hydrocracking process on residues to use for their desulfurization, but rather it should be the effluent of the catalytic The reaction zone continues in the presence of considerable amounts of hydrogen, as this inevitably occurs the catalytic reaction zone passes into the next reaction zone, and in connection with certain Separation and return measures are implemented. How this is to be done in detail, cannot be inferred from the literature reference. There is only the hint that a catalytic desulphurized "synthetic" oil then subjected to further hydrocracking according to one of the procedures, as they have been developed for feeds obtained by distillation, can be subjected. One such hydrocracking is also catalytic; it is in this embodiment of the known then a two-stage process with catalytic conversion in both stages. Such a thing However, the method of the invention does not seek to proceed.

In the same literary passage there is also the note that reactions of hydrocracking with relatively low risk of catalyst coking carried out more slowly and even at 288 ° C can be. However, these are only the results of the laboratory scientific studies on the lower temperature ranges of the start of the reaction of the interest Reactions; an indication of the procedure for a company with high sales industrial processes cannot be derived from this reference. Accordingly, in the same Reference pointed out that higher temperatures are used in industrial processes. . Also the references in the reference that in the absence of metal impurities in the feed a catalyst life of 100 days or longer can be achieved and that bifunctional Catalysts by pretreating the feed with hydrogen or by performing the Hydrocracking in two stages with different catalysts in the two hydrocracking stages can be protected from contamination, give no indication of the working method according to the rules the invention.

Thermal cracking processes for the conversion of hydrocarbons to lower boiling products have long been part of the state of the art (Gruse and Stevens, Chemical Technology of Petroleum, 3rd edition, New York, Toronto, London, 1960, p. 344). In the case of the method of the invention However, the prescribed procedure includes that from the catalytic reaction stage to the In the reaction zone of the further cracking reaction, material flowing inevitably requires considerable amounts of hydrogen. From this reference it cannot be seen how a considerable amount of hydrogen flowing out of a catalytic reaction stage containing material in connection with special separation and return measures in another Reaction stage can not be converted catalytically, so that the special with the invention Process desired results and benefits can be achieved.

It is therefore the object of the invention that is highest boiling, normally nondestillable components of a black oil feed to a conversion in supplying more valuable hydrocarbon products, for example gas oil fractions, thereby at the same time thorough desulphurisation to values, for example below 1.0 percent by weight to ensure agglomeration and polymerization of those dispersed in such feedstocks asphaltic components, which practically excludes conversion into valuable oil products and, in conjunction with the sulfur content, leads to rapid catalyst deactivation and both the yields of valuable products and the possible service life and the Increase the life of the catalyst.

This object is achieved by a method of the type mentioned at the beginning is marked that one

(a) heating the feedstock to a temperature in the range of 260 to 413 ° C;

(b) the heated feed in the catalytic reaction zone at a pressure greater than 68 atmospheres with hydrogen,

(c) the resulting reaction zorie effluent in a first separation zone at approximately the same pressure like that of the catalytic reaction zone into a first vapor phase and a first liquid phase separates,

(d) the first vapor phase in a second separation zone at about the same pressure as in the first

Separation zone and at reduced temperature into a hydrogen-rich second vapor phase and a second liquid phase separates,

(e) at least part of the second. Vapor phase returns to the catalytic reaction zone,

(f) at least a portion of the first liquid phase in a third separation zone at approximately the same temperature into a third vapor phase and a third liquid phase separates,

(g) at least a portion of the third liquid phase in a non-catalytic thermal reaction zone cracks,

(h) separating the resulting cracked product effluent into a fourth liquid phase and a fourth vapor phase in a fourth separation zone at a reduced pressure of 1 ata to 6.8 ata, and
(i) the fourth liquid phase in a fifth separation zone at a reduced pressure between subatmospheric pressure and 3.4 atm. into an asphaltic residue and at least one fifth liquid phase containing distillable hydrocarbons with reduced sulfur content • separates.

This creates a method that is very far-reaching in a simple and economical manner Conversion, for example of 70 to 80 percent by volume, of such black oils into largely desulphurized Distillable hydrocarbons are permitted, and this with a long service life of the catalyst in the catalytic conversion stage. Due to the special combination of the series connection of catalytic conversion and thermal cracking with specific separation and recycling measures This creates a composite process in which, among other things, the separations are almost exclusively through extremely simple phase separations of gaseous and liquid phases in operational and technical terms Very simple separators in terms of cost can be carried out.

Preferably at least part of the fifth liquid phase is recycled and with the third liquid phase combined in such an amount that a ratio of the combined feed to the thermal reaction zone of about 1.1: 1 to about 4.5: 1, especially about 1.2: 1 to about 3: 1, results.

According to a particularly preferred mode of operation, the fifth separation zone consists of a vacuum column, those used to concentrate the unconverted asphaltic residue and to generate it at least one of a heavy vacuum gas oil, a light vacuum gas oil, and one for reprocessing .suitable waxy fraction, hereinafter referred to as "slop wax" fraction, is driven. Preferably the latter (with or without some of the heavy vacuum gas oil) becomes the thermal cracking zone returned If the desired product distribution requires it or makes it expedient, can part of the slop wax fraction is returned and with the fresh black oil feed for the fixed bed reaction zone be united.

The total feed to the first fixed bed catalytic hydrogenation zone, including recycled hydrogen and make-up hydrogen to maintain pressure and replenish the hydrogen consumed in the overall process, is preferably heated ^{to a temperature in the range of 343 to 399 or 413 ° C.} The temperature to which the feed to the catalytic reaction zone is heated is controlled within the aforesaid range by monitoring the temperature of the product effluent from the reaction zone. Since the main reactions taking place are exothermic, there is a temperature increase as the feedstock and the hydrogen pass through the catalyst bed. One technically and economically

Usable catalyst life is achieved when the maximum catalyst temperature, which is practical coincides with the temperature of the product outflow, is kept no higher than about 427 ° C. According to a further preferred feature, the outflow of the first reaction zone enters the first separation zone a temperature of 371 to 413 ° C, to ensure that the heavy components of the reaction zone product effluent do not enter the Mainly vapor phase are carried.

As a measure for controlling the temperature in the fixed catalyst bed, a stream of cooling hydrogen or a cooling liquid or both can be introduced in a conventional manner at one or more intermediate points of the catalyst bed. Preferably the catalytic reaction zone is maintained under a pressure of 68 to 272 atmospheres. The hydrocarbon feedstock may, with an hourly space velocity of the liquid of 0.5 to 10.0, based on the Kohlenwasserstofffrischbe-destiny exclusively recirculated diluting play and / or any of applied for temperature control of cooling flows are directed ^v lyst over the Kata. The hydrogen concentration should appropriately 890qStandard-m ³ / are in the range of about 890 to about 10,001th The ratio of the combined feed, defined as the total volumes of liquid feed per volume of fresh hydrocarbon feed, should desirably be in the range of about 1.1: 1 to about 3.5: 1.

The catalyst located in the fixed bed catalytic reaction or conversion zone can are characterized as a material containing a metal component having hydrogenation activity, wherein this component with a suitable high-

Melting carrier material based on inorganic oxides of either synthetic or natural Origin is united. The exact composition and method of making the carrier material are for the method according to the invention

not essential, but it should be noted that that a silica-containing carrier, for example of 88.0 percent by weight aluminum oxide and 12.0 percent by weight silicon oxide or from 63.0 percent by weight aluminum oxide and 37.0 percent by weight Silica, is generally preferred. Suitable metal components with hydrogenation activity are those based on metals of groups VIb and VIII of the periodic table (periodic table of the elements according to E. H. Sargent & Com-

pany, 1964). Thus, the catalytic composite can consist of one or more metal components of the group molybdenum, tungsten, chromium, iron, cobalt, nickel, platinum, iridium. Osmium, rhodium, Ruthenium, and mixtures and compounds

of which, included. The concentration of the kaialytic Metal component or components depends primarily on the metal chosen in the individual case as well the properties of the input material. Example

The metal components of group VIb are passed into a first separation zone at about 427 ° C., generally in an amount in the range from 1.0 (hereinafter referred to as "hot separator") to 20.0 percent by weight, and the iron group. The main task of the hot separator is metals in an amount in the range from 0.2 to present the mixed-phase product effluent in an amount to 10.0 percent by weight, while the noble 5 main vapor phase, which is rich in group VIII water metals, preferably in an amount substance, and a mainly liquid phase, which contains in the range of 0.1 to 5.0 percent by weight in the presence of a certain amount of dissolved hydrogen, all values being calculated as if these were to be separated. Preferably, all of the reaction compounds in the catalyst are used in elemental product effluent as a heat exchange medium if they were to be present. The high-melting point can reach its temperature in the range from 371 to an inorganic carrier material with which the metal components which are catalytically active at 413.degree. C. and preferably below about 399.degree. C. are combined. The mainly vapor phase from the z. B. aluminum oxide, silicon dioxide, zirconium oxide, hot separator is incorporated into a second separation zone - magnesium oxide, titanium oxide, boron oxide, strontium, which is referred to below as "cold separator" oxide, hafnium oxide and mixtures of two or 15. The cold separator works with about the several such components, e.g. B. Siliciumdi- same pressure as the hot separator, but with oxide - aluminum oxide, aluminum oxide - silicon dioxide a much lower temperature in the range of oxide - boron phosphate, silicon dioxide - zirconium oxide, 16 to 6O ⁰ C. The cold separator is used to enrich silicon dioxide - magnesium oxide , Silicon dioxide of hydrogen in a second phase, mainly titanium oxide, aluminum oxide - zirconium oxide, aluminum vapor phase. This hydrogen-rich steam oxide - magnesium oxide, silicon dioxide-alumi- phase, which contains, for example, about 82.5 mol percent hydrogennium oxide-titanium oxide, aluminum oxide-magnesium and only about 2.3 mol percent propane and heavier oxide-zirconium oxide or silicon dioxide-aluminum hydrocarbons, is available Use as oxide-boron oxide include. Return stream for union with the fresh

For clarification, some of the 25 black oil feedstocks are available below. Butane and terms used in this document are defined. Heavier hydrocarbons are condensed in the term "about the same pressure as" or separator and in the form of a second, a similar formulation indicates that the pressure, mainly liquid phase, is withdrawn from it at which a subsequent vessel is held The first liquid phase from the hot separator, the same as the pressure in the preceding vessel 30, can be partially recycled and replaced with the fresh one, reduced only by the pressure drop that occurs due to hydrocarbon feedstock pooling of the media flow through the system. If so that it serves as a diluent for the heavy constituents which are sensitive therein, for example the first catalytic reaction zone. The amount is kept at a pressure of about 190 atmospheres, the liquid phase branched off in this way operates the first separation zone, ie the one below 35 is chosen so that the ratio of the combined separation zone called "hot separator" when fed to the catalytic reaction zone , a pressure of about 182 atm. The expression "roughly defines the same temperature as the total volume of liquid charge as" or a similar formula per volume of fresh liquid charge, preferably lierung indicates that only a temperature reduction in the range of about 1.1: 1 to about 3.5: 1 is located, is present, the ¹ Uf the normal temperature decrease 40 the remaining portion of the liquid in the main action 'niolge the flow of material from one part of the system to phase out of the hot separator is in a third introduced on the conversion of tactile separation zone to another or, hereinafter referred to as "Heatable heat in latent heat through relaxation flash zone" is called. The hot nash zone is called "flash vaporization", where a pressure drop occurs at about the same temperature as that from the irut. is based. The expression "hydrocarbons containing liquid phase withdrawn from the hot separator in the gasoline range" denotes those hydrocarbons which are liquid under normal conditions, but at a much lower pressure, which are in the range from 10.2 to 23.8 atmospheres. The phase from the hot flash zone, which is mainly vaporous at temperatures up to about 204 or 232 ° C, includes boiling, including pentanes and heavier hydrocarbons, which are below a hydrocarbon and - in some places - 5 ° temperature of about 343 ° C boil, and contains a butanes. Similarly, a commonly used boiling relatively small amount of hydrocarbon range for gas oil is an initial boiling range that is normally assigned to the pre-boiling range of about 343 ° C and an end boiling point rem gas oil. This mainly of about 566 ° C. The higher-boiling, about 70 to 80% vaporous stream can be combined with the liquid stream, ie the heavy gas oil, 55 from the cold separator and the Gemisct is typically combined as a fraction with a then in a "cold flashone" should be introduced, at an initial boiling point of around 399 ° C. It C. at a pressure between atmospheric pressure and etws is, however, to be noted that a "light gas oil" atm and 4.1 and a temperature from 16 to 60 ^c
an initial boiling point as low as about 177 ° C. The main boiling point and a final boiling point as high as about 427 ^{° C.} Cause the liquid phase in a thermal cracking can have. in the case of about de gas oil «, if necessary, they have as low an initial boiling temperature and a pressure of 10.2 bi point as about 343 ° C. 23.8 atm. The thermally cracked product flow

The measures of the procedure are subsequently carried out at a temperature of 466 to 510 ° C and one

standing using exemplary information 65 pressure from 2.6 to 6.8 atmospheres, then ai

and values further illustrated. chilled to a temperature of about 371X and then

The entire product effluent from the catalytic is introduced into a fourth separation zone, which follows

The reaction zone is referred to as the "flash fractionation zone" at a maximum temperature. The flü <

Liquid phase from the flash fractionation zone is introduced into a vacuum column which is maintained at a pressure of 25 to 75 mm Hg absolute. The vacuum column serves as the fifth separation zone. Their main task is the enrichment and separation of an asphaltic residue which contains sulfur-containing compounds of high molecular weight and which is essentially free of distillable hydrocarbons. In general, gas oil streams are a separate light vacuum gas oil having a boiling range 160-399 ⁰ C, a medium vacuum gas oil boiling range 399-527 ° C and a heavy vacuum gas oil which contains the remaining distillable hydrocarbons removed from the vacuum column in the form. It is clear that the boiling ranges cut in the individual case of the various gas oil streams from the vacuum column are not of essential importance for the invention, but can generally be determined according to the respective wishes and requirements of the refinery and the market.

Preferably, in the vacuum column also Slopwachsfraktion is separated, containing the boiling mainly above 527 ° C distillable components, but also may consist of about 399 ⁰ C to boiling Gesamtdestillierbaren up to about 30 volume percent. A portion of the slop wax fraction can be recycled to the catalytic reaction zone, however, in general, recycling to the thermal coil is preferred to increase the yield of the more desirable gas oils. The amount of slop wax recycled in this manner is selected so that the ratio of the combined feed to the thermal reaction coil is above about 1.2: 1 and generally no more than about 3.0: 1.

One of the main advantages of the method according to the invention is that it extends the useful ones Catalyst life associated with a fixed bed catalytic reaction zone. This is based mainly due to the fact that desulfurization was performed to values less than about i, 0 weight percent is achieved at a relatively low operational sharpness, with the result that the formation of polymeric products is reduced or suppressed. Furthermore, the vacuum flash column can be kept much smaller, which is an additional advantage in terms of process technology and economy of the overall process means. The procedure continues to increased yields of the more valuable gas oils.

To further illustrate the features explained, the conversion of a bottoms product from a vacuum column with a specific gravity of 1.0291 and an ASTM 20.0 volume percent distillation temperature of about 569 ° C is described below in connection with the drawing as an example. The feed also contained 4,000 parts per million nitrogen, 5.5 weight percent sulfur, 100 parts per million nickel and vanadium, and 6.0 weight percent heptane-insoluble asphaltenes, and had a Conradson coke residue of 21.0 weight percent. The explanation is based on a large-scale plant with a throughput of around 1272m ³ / day (1,272,000 l / day). The drawing shows the course of the process using a simplified flow diagram in which details that are unnecessary for the explanation and understanding of the work measures have been omitted. The processing conditions and the compositions of the feed and other material streams are provided for purposes of illustration, but the invention is not limited thereto.

During processing, the task is to convert the feedstock as largely as possible into distillable hydrocarbons, which can be obtained by conventional distillation methods in commonly used fractionation devices. The feed is in a catalytic fixed bed desulfurization and conversion zone in a mixture with about 1780 standard m ^{3 of} hydrogen per! 0001 feed, based only on the fresh feed excluding any recycle streams, at a catalyst bed inlet temperature of about 370 ° C and one Processed pressure of about 212 atm. The liquid hourly space velocity based on the fresh feed only is about 0.5 and the ratio of the combined liquid feed is about 2.0: 1. According to the drawing, the feed is introduced into the plant through a line 1 in an amount of about 185.94 mol / h. After a heat exchange, not shown, with various hot outflows, the material flows into a heater 5, mixed with a recirculated hydrogen-rich stream coming from a line 3 and a liquid recirculating stream from the bottom of the hot separator, which is mixed through a line 2. Make-up hydrogen from a suitable external source, to maintain the system pressure and to replace the hydrogen consumed in the overall process, is introduced through a line 4. The total charge to the heater is at a temperature of about 260 ^° C. This temperature is increased to about 371 ^° C., measured at the inlet to the catalyst bed. The total cover heated in this way Kung flows through a line 6 into a catalytic fixed bed reaction zone 7. The catalyst arranged in the reaction zone 7 is a composition of 88.0 percent by weight of aluminum oxide and 12.0 percent by weight of silicon dioxide, combined with 2.0 percent by weight of nickel and about 16, 0 weight percent molybdenum, calculated as elemental metals.

Component analyzes of the total feed to the reaction zone are in Table I below compiled In the table, the material in line 3 includes both recycled and make-up hydrogen, the line 2 identifies the liquid return material from the hot separator 9, and the line 1 carries the entire charge.

Table I Feed to the reaction zone

Ingredient, moles / hr

nitrogen

hydrogen

Hydrogen sulfide

management

li, 07 8 430.09

739.02

1.85 175.52

2636

12.93 8605.61

76538

continuation management
2 1 Component. Moles / h 3 31.82
7.53
4.17
2.06
0.92
1.29
3.19
11.23
16.25
22.75
67.16
9.27
78.78 1150.86
140.67
71.73
26.55
7.52
5.99
5.19
11.47
16.25
22.75
67.16
9.27
78.78
185.94 methane
Ethane
propane
Butane
Pentanes
Hexanes
C ₇ -IoO ⁰ C
160 to 270 ⁰ C ...
270 to 343 ° C ...
343 to 399 ° C ...
399 to 527 ° C ...
527 ° C and
about it
Residue
Input material .. 1119.04
133.14
67.56
24.49
6.60
4.70
2.00
0.24

The effluent formed by the conversion product, which in the mixed-phase state through a Line 8 flows off at a temperature of about 427 ° C, is used as a heat exchange medium and then introduced into a hot separator 9 at a temperature of 413 ° C. and a pressure of about 206 atü. A mainly vapor phase is passed through line 10 and one is the main liquid phase is drawn off through a line 12. In these documents, the Expressions "mainly vaporous" or "mainly liquid" mean the state of an individual case current in which the majority of the components present under standard or normal conditions is normally gaseous or normally liquid. At least some of the from the Hot separator 9 withdrawn liquid phase is through line 2 to combine with the fresh Diverted hydrocarbon feed, it serves as a diluent for the heavier components of the input material. The amount of this recirculated stream is 460.15 mol / h, so that a The combined liquid feed ratio is 2.0: 1.

The separation of the reaction zone effluent in the hot separator 9 is shown below Tables shown, where the line8 the Charging for the separator (<L h. The reaction zone outflow), line 10 is the vapor phase and line 12 is the net flow characterize the liquid phase without the portion returned through line 2.

Table II
Analyzes of the flows from the hot separator

Component mole / h 8th management
10 12th nitrogen
hydrogen
Sulphurous water
material.
methane 12.92
7679.21
906.43
1188.95 9.40
7345.65
856.33
1128.48 1.67
158.04
23.74
28.65

Ingredient, moles / hr 8th management
10 12th Ethane
propane
Butane
Pentanes
Hexanes
C ₇ to 160 ⁰ C ....
160 to 270 ⁰ C
270 to 343 ° C ...
343 to 399 ⁰ C ...
399 to 527 ° C ...
527 ° C and
about it
Residue .160.61
89.52
38.85
14.55
17.60
32.10
68.54
51.51
50.89
129.45
17.61
149.72 146.30
81.59
34.93
12.81
15.15
26.02
47.20
20.62
7.67
1.81 6.78
3.76
1.86.
0.83
1.16
2.88
10.11
14.63
20.48
60.47
8.34
70.94

From Table II it can be seen that the material flowing through line 10 is 75.5 mole percent consists of hydrogen and only about 1.35 mol percent of pentanes and heavier ones, which are liquid under normal conditions Includes hydrocarbons. It is therefore mainly a gaseous phase. The through Stream flowing through line 12 comprises about 19.9 mole percent butanes and lighter portions, not counting Hydrogen, which is dissolved in the heavy hydrocarbons, and is therefore considered to be the main one address the liquid phase.

The portion of the bottom flow from the hot separator that is not branched off through line 2 flows on through line 12 into a hot flash zone 13. A pressure reduction valve (not shown in the drawing) brings about a pressure reduction; the stream then enters the hot flash zone 13, at a pressure of about 17 atmospheres and a temperature of about 408 ° C. As set out below, the main task of the hot flash zone 13 is to concentrate the heavier components in a liquid phase, the then serves as a feed to a thermal cracking coil 17. From Table 111 below it can be seen that the vapor phase of line 14 consists of about 89.2 mol percent of ^{material boiling below about 270 °} C., not counting hydrogen, while the liquid stream of line 16 is about 6.3 mol percent of hydrogen not counting, includes

Table ΠΙ
Analyzes of the flows from the hot flash zone

Ingredient, moles / hr

nitrogen

hydrogen

Hydrogen sulfide.

methane

Ethane

propane

Butane

Pentanes

Hexanes

management

14th

1.45

151.87

22.47

27.49

6.15

3.36

1.61

0.69

0.93

16

0.22
6.17
1.27
1.16
0.63
t), 4Q
0.24
0.14
0.23

continuation

Ingredient, moles / hr

C _{7 to} i60 ° C

160 to 27O ⁰ C

270 to 343 ° C

343 to 399 ° C

399-527 ° C

527 ° C and above.
Residue

management

14th

2.12 5.89 4.73 3.10 1.92 0.01

16

0.76

4.22

9.90

17.37

58.55

8.33

70.94 The from the hot separator 9 drawn off through line 10, vapor to the main phase is cooled to a temperature of about 49 ⁰ C and at a pressure of about 204 atmospheres in the KaItabscheider 11 introduced a hydrogen-rich gaseous phase is fed through line 3 withdrawn and returned to line 1 for combination with the fresh hydrocarbon feed. A mainly liquid phase is produced from the cold

separator 11 withdrawn through a line 15. The separation brought about in the cold separator 11 can be seen from Table V below, with no make-up hydrogen in relation to line 3 is included.

The liquid phase of line 16 is mixed with about 1.0 percent by weight of water vapor at 22.5 atmospheres, and the mixture enters thermal coil 17 at a temperature of about 393 degrees Celsius and a pressure of about 11 atmospheres. The thermally cracked product effluent, which has a pressure of about 3.7 atmospheres and a temperature of about 499 ° C., flows after cooling through a line 18 into a rectifying flash fractionation zone 19, at a temperature of about 371 ° C. and a pressure of about 3.7 atm. A vapor phase is withdrawn from flash fractionation zone 19 through line 20 and a liquid phase through line 24. The latter is introduced into a vacuum flash ^{column 25 at a temperature of about 399 °} C. The vacuum column works at about 25 mm Hg absolute, the pressure is brought about by conventional vacuum ejectors, which are not shown in the drawing. The separation effected in the flash fractionation zone 18 is shown in Table IV below, which also gives the constituent analysis of the thermally cracked product effluent flowing in through line 18, not counting water.

Table IV

Analyzes of the flash fractionation zone flows

45

Ingredient, moles / hr

nitrogen

hydrogen

Hydrogen sulfide ...

methane

Ethane

propane

Butane

Pentanes

Hexanes

C ₇ to 160 ° C

160 to 27O ⁰ C

270 to 343 ° C

343 to 399 ° C

399-527 ° C

527 ° C and above ...
Residue

management

18th 20th 0.22 0,? 2 11.87 11.82 3.68 3.65 22.34 22.23 16.93 16.70 22.40 21.92 16.53 15.87 17.77 16.56 14.55 13.06 33.83 28.31 50.47 33.80 30.33 10.29 24.49 2.75 56.88 0.26 10.00 - 39.41 -

24

0.05

0.03

0.11

0.23

0.48

0.66

1.21

1.49

5.52

16.67

20.04

21.74

56.62

10.00

39.41 Table V
Analyzes of the cold separator flows

Ingredient, moles / hr

nitrogen

hydrogen

Hydrogen sulfide.

methane

Ethane

propane

Butane

Pentanes

Hexanes

C ₇ to 160 ° C

160 to 270 ° C

270 to 343 ° C

343 to 399 ⁰ C

399-527 ° C

527 ° C and above.
Residue

management
3 15

9.29

7274.70

739.02

1091.19

133.14

67.56

24.49

6.60

4.70

2.00

0.24

0.11
70.95
117.31
37.29
33.16
14.03
10.44

6.21
10.45
24.02
46.96
20.62

7.67

1.81

The vacuum flash column 25 is used to concentrate the residue, which is in an amount of 39.41 mol / h flows off through a line 28, and for the separation of a light vacuum gas oil (LVGO) and heavy vacuum gas oil (HVGO) withdrawn through lines 26 and 27, respectively. The Heavy vacuum gas oil with a boiling range of 399 to 566 ° C falls in an amount of about 66.62 mol / h on, the light vacuum gas oil in an amount of 58.45 mol / h. Lighter ones boiling below 160 ° C Portions are removed from the vacuum flash column 25 by the ejector, not shown in the drawing removed.

In the sense of a completion is in that

A flow diagram also shows a cold flash zone 25, which in the exemplary embodiment is a separation of the

. Mixture of the vapors from the hot flash zone (line 14) and the vapors from the flash fractionation zone (Line 20) and the liquid from the cold separator (line 15). With a technical Plant can remove the vapors from the flash fractionation zone because of their relatively high olefin content are expediently obtained separately. Component analyzes from which those in the cold flash zone 21 brought about separation is shown in Table VI below.

1 9S4 004

15th

Table V! , Analyzes of the currents in the cold flash zone Table VII Overall product yields

Ingredient, moles / hr nitrogen hydrogen

Hydrogen sulfide.

methane

Ethane ...

propane

Butane

Pentenes

Hexanes

C ₇ to 160 ⁰ C .... 160 to 270 ⁰ C ... 270 to 343 ° C ... 343 to 399 ° C ... 399 to 527 ° C ...

527 ° C and above

Residue

management feed 22nd 1.78 1.78 234.64 232 ^ 3 143.43 96.75 87.01 82.63 56.01 47.12 39.31 26.24 27.92 11.87 23.46 4.84 24.44 2 ^ 4 54.45 1.86 86.65 0.05 35.64 - 13.52 - 3.99 - 0.01 -

2.11

46.68

438

8.89

13.07

16.05

18.62

21.90

52.59

86.60

35.64

13.52

3.99

0.01

₅ component Moles / h Butane 28.58
24.67
25.93
59.97
103.32
55.68
35.26 Pentanes ■,. 60.61
10.01 Hexanes 39.41 C ₇ to 160 ° C j 160 to 270 ⁰ C 270 to 343 ° C 343 to 399 ° C ¹⁵ 399-527 ° C 527 ° C and above Residue

Under normal conditions, gaseous components are passed through a line 22 to a not shown Means for obtaining the light ends withdrawn, while liquid in northern conditions Hydrocarbons including butanes for further separation by fractionation by a Line 23 can be removed.

The total product yields excluding the proportions gaseous under normal conditions, however including butanes and hydrocarbons which are liquid under normal conditions and which are produced from the Vacuum ejectors and the device for obtaining light ends (line 22) are listed in Table VII below.

The sulfur content of the distillable hydrocarbon products is about 0.83 percent by weight. In previously known processing methods that do not have a thermal coil as an integral part of the The processing path must be catalytic

2s fixed bed reaction zone must necessarily be operated at a considerably higher operating severity, in order to produce the greatest possible amount of distillable parts. The method according to the invention enables a reduction in the operating sharpness, as measured by the inlet temperature to the catalyst bed, was around 28 to 56 ° C, which is a very significant decrease. With regard to the extension of the operating time during which the catalytic composition works in a technically and economically viable manner without the occurrence of substantial deactivation, the method according to the invention leads to an increase in the catalyst life \ im 50 to 80%, which is a very substantial extension of the actual operating periods Furthermore, a considerably smaller vacuum column is sufficient; in the technical example explained, the vacuum column can be smaller corresponding to a reduction in the nominal diameter from 335 to 262 cm.

1 sheet of drawings

Claims (1)

Patent claims: 1. A process for converting and desulphurising a hydrocarbon feedstock of which at least 10% boils above 566 ° C and which has a relatively low metal content, especially less than about ISO parts per million total metals, calculated in the elemental state, but a high sulfur content, in particular "> Particularly more than 2.0 percent by weight, with the formation of lower-boiling distillable hydrocarbon products of reduced sulfur content, in which the 'hydrocarbon feedstock reacted after heating in a catalytic reaction zone at increased pressure in the presence of hydrogen to remove sulfur compounds and generate lower-boiling hydrocarbons reaction mixture obtained separately and the resulting liquid fractions are subjected to a further ² ^ cracking reaction with subsequent work-up of the reaction products, characterized in that one