DE102014006327A1 - Process and plant for the extraction of crude oil products - Google Patents

Abstract

A process for the recovery of crude oil products is proposed in which a gaseous stream (d) is formed from a first crude stream (b) and the gaseous stream (d) is subjected at least in part to a steam cracking process (1), wherein in the steam cracking process (1 ) a quenching gas stream (e) is generated which is at least partially quenched to give a quenching effluent (g) with a liquid hydrocarbon stream (f). It is provided that at least part of the Quenchabstroms (g) together with a second crude oil stream (c) to obtain distillation effluents (h, i, k, p, r) by distillation separate (5, 8). An installation (100) set up for carrying out the method is likewise the subject of the invention.

Description

The invention relates to a method and a plant for the production of crude oil products according to the preambles of the independent claims.

State of the art

Crude oil is first desalinated in known refinery processes and, after heating, subjected to fractional distillation at atmospheric pressure (hereinafter referred to as atmospheric distillation). The remaining so-called atmospheric residue is fed to a vacuum distillation.

However, not all of the fractions obtained in atmospheric distillation and vacuum distillation are profitable. A part of the compounds contained therein can therefore be catalytically converted, for example, and upgraded in this way. However, this does not always succeed completely. A thermal conversion of crude oil components by steam cracking (engl. Steam Cracking) is also known.

The object of the invention is to improve corresponding methods and devices and in particular to increase the yield of high-grade crude oil products.

Disclosure of the invention

This object is achieved by a method and a system according to the features of the independent claims. Embodiments are the subject of the respective subclaims and the following description.

Reference should be made to the relevant technical literature for the terms used below and technical details of the methods used (see, for example, US Pat Zimmermann, H. and Walzl, R .: Ethylene, In: Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, Online Publication 2007, DOI: 10.1002 / 14356007.a10_045.pub2 , such as Irion, WW and Neuwirth, OS: Oil Refining, In: Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, Online Publication 2000, DOI: 10.1002 / 14356007.a18_051 ).

Steam cracking processes are generally carried out by means of tube reactors whose reaction tubes, the so-called coils, can be operated individually or in groups under the same or different conditions. Reaction tubes operated under identical or comparable conditions or groups of reaction tubes, but also tube reactors operated under uniform conditions, are referred to below as "cracking furnaces". In the language used here, a cracking furnace is therefore a structural unit used for steam cracking in which identical or comparable reaction conditions are present. A steam cracking plant may comprise one or more cracking furnaces.

A fission gas stream is understood here to mean a gaseous stream which is formed from the effluent of one or more cracking furnaces. The cracked gas stream (also referred to as cracker effluent) is typically, in a first cooling step, quenched in a quench cooler, such as a transfer line exchanger (TLE), with cooling water and then in a second cooling step. H. Mix with a liquid hydrocarbon stream, cooled.

In the literature, sometimes the first cooling step, i. H. the cooling of the quenching gas with cooling water, for example in the quench cooler, referred to as quenching. However, in this first cooling step, the cracked gas is only indirectly cooled and not mixed, as in the second cooling step, with a liquid hydrocarbon stream. The second cooling step may therefore also be referred to as oil quench for better distinctness. The stream formed by combining the cracked gas stream with the liquid stream used for quenching is referred to herein as quench effluent.

Advantages of the invention

The invention proposes a method for recovering crude oil products in which a gaseous stream is formed from a first crude oil stream and the gaseous stream is at least partially subjected to a steam cracking process. In the steam cracking process, a split gas flow is generated.

In the context of the present invention, at least part of the gaseous stream formed during the evaporation of the crude oil may be supplied to one or more cracking furnaces alone or after being combined with one or more further streams, for example one or more recycle streams. If several cracking furnaces are present, they can also be charged with different currents. As is generally known, the charging of the cracking furnaces takes place in each case after the addition of water vapor.

The resulting cracked gas stream is at least partially quenched to give a quench effluent stream with a liquid hydrocarbon stream. The present invention proposes at least a portion of the Quenchabstroms together with a second crude oil stream to obtain distillate separated by distillation.

Since the Quenchabstrom contains a considerable proportion of finely divided oil droplets from the quenching liquid stream and heavy components (oils, tars and the like), it is first freed in conventional steam cracking process in a so-called oil column of corresponding components. Only downstream of the oil column, a corresponding stream of the known separation stages for recovering the hydrocarbon products from the cracking gas can be supplied. According to the invention, however, the said components from the Quenchabstrom in the subsequent separation by distillation, which is subjected to the Quenchabstrom together with the second crude oil stream, removed and go into the corresponding (s) fraction (s).

A particularly advantageous embodiment of the invention provides to form said gaseous stream by evaporation from the first crude oil stream, wherein a portion of the crude oil stream remaining liquid during the evaporation is used at least in part to form the liquid hydrocarbon stream used for quenching. By quenching with the liquid fraction remaining at the evaporation of the crude oil stream, or a corresponding part thereof, in the Quenchabstrom only those (heavier) components are contained, as they are also found in conventional crude oil streams, which are subjected to atmospheric distillation. The remaining in the evaporation of the crude oil stream liquid fraction can also be cooled before its use, with its heat can be transferred to other streams.

In contrast to conventional methods in which a quench oil circuit is provided, in this embodiment of the invention, therefore, the liquid hydrocarbon stream used for quenching is used only once for quenching. A great advantage of this process variant is therefore that no oil circuit is needed for the quench, in which the oil usually ages very strongly by chemical reactions, increases greatly in viscosity, and thereby greatly decreases in value. In the said process variant, such aging reactions do not play a role for the reasons explained. Another advantage that results from not using an oil circuit, is that, for example, the conventionally provided heat recovery from the cracking gas eliminated by consuming heat ashtray in the oil circuit and the heat can be fed via the Quenchabstrom directly another consumer. The heat can be used, for example, for (pre) heating the streams used in the atmospheric distillation.

As mentioned, in the context of the present invention, at least part of the quench effluent is separated by distillation together with another stream of crude oil to obtain distillate effluents. This distillative separation is advantageously carried out initially in a distillation column for fractional distillation at atmospheric distillation, as it is also used in a conventional refinery. The atmospheric distillation may be followed by a vacuum distillation in a distillation column equipped therefor. All streams (cuts, fractions) formed in the distillation (for example, atmospheric distillation and / or vacuum distillation) are referred to herein as distillation effluents.

In other words, in an advantageous embodiment, the present invention proposes to treat the quench effluent, like conventional crude oil streams, first in an atmospheric distillation. In atmospheric distillation, the products of the steam cracking process, such as ethylene and other light hydrocarbons, pass into the top stream of the distillation column. At the same time, the classical sections of the crude oil stream (and the liquid stream used for quenching) can be produced in this distillation column.

In the context of the present invention, therefore, the oil column conventionally used in a steam cracking process and the distillation column used for atmospheric distillation in a conventional refinery process are functionally combined. The products of the steam cracking process withdrawn from the top or from the top of the atmospheric distillation column may be subjected, together with corresponding light products from the crude oil stream, if present, to the post-cracking gas separation steps usually following the oil column of a steam cracking process.

For example, in this case, first of all a water wash can be used, in which the naphtha which may possibly still be contained in a corresponding stream is deposited in liquid form. After washing with water, hydrocarbons having one to four carbon atoms typically remain in the gas phase. These can then be subjected to known separation sequences (Demethanizer First, Deethanizer First, etc., for details, see the cited technical literature).

The resulting in the column for atmospheric distillation further distillation effluents are composed of heavier hydrocarbons derived predominantly from the uncleaved crude oil or the liquid stream used for quenching. These are, for example, so-called atmospheric gas oil (English: Atmospheric Gas Oil, AGO) and the mentioned atmospheric residues.

Further advantages can be achieved if certain hydrocarbons, for example contained in the cracked gas or in the further crude oil stream, are again subjected to the steam cracking process. Such streams subjected to the steam cracking process are referred to as recycle streams. Recycled streams can be combined and fed together or separately, possibly together with fresh inserts, identical or different cracking furnaces. As a fresh use of the present invention, the already explained, formed in the evaporation of the crude oil stream gaseous stream is used, but it can also be used other, supplied from the plant boundary streams.

The separation of the fractions provided as recycle streams can be carried out, for example, in the customary separation devices which are provided in the context of the present invention, similar to conventional steam-splitting processes. Separate separation of corresponding light fractions, as conventionally carried out in a refinery, can therefore be dispensed with. Such light fractions, because they can be fed to the steam cracking process as recycle streams, need not be stored in tanks as in conventional refinery plants. As also explained below, the compounds contained in corresponding streams can also be at least partially further implemented.

Overall, the measures according to the invention provide the advantage that it is possible to dispense with an oil column, and that no pyrolysis oil and no pyrolysis gasoline are produced as separate products. The compounds which conventionally pass into the pyrolysis oil and the pyrolysis gasoline are found again in the use of the process according to the invention in the corresponding distillation effluents (for example from the atmospheric distillation and the vacuum distillation).

The process according to the invention can also be configured by recycling all distillation effluents which are not desired as products, such that production of typical refinery products such as gasoline, diesel, heating oil etc. no longer occurs. The said components may be used, for example after appropriate treatment such as hydrotreats or (mild) hydrocracking, together or separately, as an insert for the steam cracking process. In such a case, for example, exclusively ethylene, propylene, butadiene, aromatics and high-pressure steam or electricity can be obtained from the crude oil used. This variant proves to be extremely economical. The method according to the invention can be flexibly adapted to the respective requirements of corresponding compounds. The present invention further enables a particularly effective utilization of the waste heat generated in a steam cracking process. This can first be used to preheat the crude oil stream, the vaporized portion of which is then subjected to the steam cracking process. Further waste heat may, for example, also be used to heat the further stream of crude oil, which is then fed to the distillation column for atmospheric distillation. Overall, this results in an advantageous energy integration and a reduction in the dissipated waste heat. Also, the quench cooler can be integrated into a corresponding heat recovery circuit, for example, by steam generated there is used to heat the crude oil stream.

The distillation separation of Quenchabstroms together with the other crude oil stream, as explained, advantageously first at atmospheric pressure and then in vacuo, so that can be used for distillation on known methods of refinery technology and appropriate methods for the treatment of the distillation effluents can be used.

As already mentioned, the distillation effluents or streams derived therefrom may also be at least partially subjected to the steam cracking process. In each case, diverted streams can be formed in each case by branching off a partial stream, combining with other streams, chemically or physically reacting at least some components in appropriate streams, heating, cooling, evaporating, condensing, etc.

With particular advantage corresponding derived streams can be formed by hydrocracking. In such processes, the distillation effluents, if appropriate after prior further separation and / or treatment, are partially or fully catalytically hydrogenated and at least partially cracked. In this way, as furnace inserts, undesired unsaturated hydrocarbons can be converted to saturated hydrocarbons and reacted again to form value products in the steam cracking process.

The recycle streams may be, in particular, atmospheric hydro (ATO) treated by hydrotreatment and / or hydrocracking, and vacuum gas oil treated by hydrotreatment and / or hydrocracking (vacuum gasoil, VGO), ie distillation residues from atmospheric distillation or atmospheric distillation Vacuum distillation, act. Suitable recycling streams are also unsaturated hydrocarbons having two to four carbon atoms and / or hydrocarbons having five to eight carbon atoms in question. Naphtha can also be used again in corresponding steam cracking processes.

In the distillation separation downstream separation stages, which are subjected to hydrocarbons having two to four carbon atoms, for example, compounds such as methane, ethylene, propylene, butadiene and / or aromatics (benzene, toluene and / or xylenes, collectively referred to as BTX) recovered and from the system are running. The vacuum residue obtained in the vacuum distillation and which can no longer be used and / or the methane formed can be burned to produce energy.

A plant for the production of crude oil products, which is adapted to form a gaseous stream from a first stream of crude oil and to subject the gaseous stream at least in part to a steam cracking process, is also the subject of the present invention. The plant is arranged such that in the steam cracking process, a cracked gas stream is generated which can be quenched at least in part to give a quench effluent stream with a liquid hydrocarbon stream. According to the invention, means are provided which are set up to separate at least part of the quench waste stream together with a second crude oil stream to obtain distillate effluents by distillation.

Such a system has all the means that enable it to carry out a method according to the invention. Advantageously, the plant according to the invention comprises at least one distillation column equipped for fractional distillation at atmospheric pressure and means adapted to supply at least part of the quench effluent and another crude oil stream to this distillation column.

Advantageously, means are furthermore provided which are set up to at least partially subject the distillation effluents or streams derived therefrom formed in this distillation column to the steam cracking process.

The invention will be explained in more detail with reference to the accompanying drawings, which show preferred embodiments of the invention.

Brief description of the drawings

1 shows a plant for the production of crude oil products according to an embodiment of the invention in partial view.

2 shows an installation for the production of crude oil products according to an embodiment of the invention in an expanded view.

In the figures, corresponding elements are given identical reference numerals and will not be explained repeatedly. The plant components shown correspond to the same steps of a process.

Embodiments of the invention

In 1 a plant for the production of crude oil products according to an embodiment of the invention is shown schematically in a partial view and in total with 100 designated.

The plant 100 supplied crude oil a is divided into two crude oil streams b and c. The crude oil stream b is in a convection zone of one or more cracking furnaces 1 preheated and placed in an evaporation tank 2 transferred. One in the evaporation tank 2 vaporizing fraction of the crude oil stream b is referred to as stream d after mixing with steam through the radiation zone of the cracking furnace (s) 1 guided, wherein a cleavage gas e is obtained.

The cracked gas e is in a quench cooler 3 cooled and then in a quenching device 4 with one in the evaporation tank 2 liquid remaining fraction of the crude oil stream b, here illustrated with stream f, quenched. A quench effluent g becomes a distillation column 5 transferred to the fractional atmospheric distillation, in which the crude oil stream c is fed.

The distillation column 5 is operated in a conventional manner, so that in this example, an atmospheric residue h and an atmospheric gas oil i are obtained. From the top or from the top of the distillation column 5 a stream k is withdrawn, the light products from the cracking furnace (s) 1 and the crude oil stream c contains. By mixing water (not shown) in a water scrubber 6 a water-naphtha mixture is separated from the stream k and as stream I into a decanter 7 transferred. In this a water flow m and a naphtha flow n is obtained.

In the water scrubber 6 gaseous remaining portions, which are substantially hydrocarbons having one to four carbon atoms are withdrawn as stream o and fed to a decomposition part, which may be formed in a known manner. In a corresponding decomposition part, for example, first a separation of methane and / or methane and ethane can be carried out (so-called Demethanizer First or Deethanizer First method).

In 2 is the plant 100 in an expanded view, ie as an extended section of an entire system 100 , illustrated and overall with 200 designated. The Indian 1 shown plant part, so at least one cracking furnace 1 with the associated facilities 2 to 4 and a distillation column equipped for fractional atmospheric distillation 5 with a water scrubber 6 and an associated decanter 7 , is with 100 designated.

As in 2 is illustrated, from an atmospheric residue, as stream h from the distillation column 5 is removed in a distillation column equipped for vacuum distillation 8th a vacuum residue p obtained in a facility 9 burned and used to generate energy, illustrated here by arrow q.

A top stream r from the distillation column 8th , so-called vacuum gas oil, becomes a hydrogenation unit 10 transferred where the stream r can be processed, for example by hydrocracking. A correspondingly processed stream s can be introduced into the steam cracking process or into one or more cracking furnaces 1 to be led back. The same applies to the above-explained stream i, the atmospheric gas oil, which is in a hydrogenation unit 11 treated and then recycled as stream t in the steam cracking process. From a stream u, which contains substantially hydrocarbons having five to eight carbon atoms, in an aromatic extraction unit 12 Aromatics separated and run as a stream v from the plant. A remaining portion may be re-subjected as stream w to the steam cracking process. The already explained stream o, which predominantly has hydrocarbons having one to four carbon atoms, can be converted into a C4 decomposition part 13 be converted, in which the product streams indicated here in total with x, for example ethylene, propylene and butadiene, can be separated. A methane stream y can be carried out from the plant and / or used for heating. Hydrocarbons not recovered as product streams x can be recycled as stream z into the steam cracking process.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• Zimmermann, H. and Walzl, R .: Ethylene, In: Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, Online Publication 2007, DOI: 10.1002 / 14356007.a10_045.pub2 [0006]
• Irion, WW and Neuwirth, OS: Oil Refining, In: Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, Online Publication 2000, DOI: 10.1002 / 14356007.a18_051 [0006]

Claims (11)

Process for the production of crude oil products, in which a gaseous stream (d) is formed from a first stream of crude oil (b) and the gaseous stream (d) is formed, at least in part, in a steam-cracking process ( 1 ), wherein in the steam cracking process ( 1 ) a quenching gas stream (e) is generated, which is quenched, at least in part, with a liquid hydrocarbon stream (f) to obtain a quenching effluent (g), characterized in that at least part of the quenching effluent (g) is mixed with a second crude oil stream (c) separated by distillation from the distillation effluents (h, i, k, p, r) ( 5 . 8th ) becomes. Process according to Claim 1, in which the distillate effluents (h, i, k, p, r) or streams (s, t, w, z) derived therefrom are at least partially recycled streams to the steam cracking process ( 1 ). Process according to Claim 2, in which by catalytic hydrogenation ( 11 atmospheric gas oil (i), catalytic hydrogenated vacuum gas oil (r), saturated hydrocarbons having two to four carbon atoms (z) and / or hydrocarbons having five to eight carbon atoms (w) are used as recycle streams. Method according to one of the preceding claims, wherein the gaseous stream (d) by evaporation ( 2 ) is formed from the first stream of crude oil (b), wherein one in the evaporation ( 2 ) liquid remaining fraction (f) is used at least in part to form the liquid hydrocarbon stream (f) used for quenching. Process according to one of the preceding claims, in which the distillative separation ( 5 . 8th ) of the quench effluent (g) initially at atmospheric pressure ( 5 ) and then in vacuo ( 8th ) he follows. Process according to one of the preceding claims, in which at least part of the distillation effluents (i, r) are converted at least by catalytic hydrogenation ( 10 . 11 ) derived currents (s, t) are formed. Process according to one of the preceding claims, in which methane, ethylene, propylene and / or butadiene (x) and / or aromatic compounds (v) are obtained. Method according to one of the preceding claims, wherein at least part of the distillation effluents (p, y) is burned for energy production. Investment ( 100 ) for obtaining crude oil products which is adapted to form a gaseous stream (d) from a first stream of crude oil (b) and the gaseous stream (d) at least partly to a steam cracking process ( 1 ), wherein in the steam cracking process ( 1 ) a cracked gas stream (e) can be generated and a quenching device ( 4 ) arranged to quench at least part of the cracked gas stream (e) with a liquid hydrocarbon stream (f) to obtain a quenching effluent (g), characterized in that means are provided which are adapted to at least one part of Quenchabstroms (g) together with a second crude oil stream (c) to obtain distillation effluents (h, i, k, p, r) separated by distillation. Investment ( 100 ) according to claim 9, comprising means adapted to carry out a method according to any one of claims 1 to 8. Investment ( 100 ) according to claim 9 or 10, which comprises at least one distillation column ( 5 . 8th ), wherein means are provided, the Quenchabstrom (g) and the second crude oil stream (c) in the at least one distillation column ( 5 . 8th ) feed.

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