PROCESS AND INSTALLATION FOR THE PRODUCT PROCESSING OF FISCHER-TROPSCH BASED RAW PRODUCTS FOR THE PRODUCTION OF PRE-FORMULATED FUELS OR STANDARD-COMPLIANT FUELS

Abstract

Processes and installations for the production of standard-compliant fuels, preferably gasoline (according to EN 228), diesel (according to EN 590 or EN 15940) and kerosene (according to ASTM D7566 or ASTM D1566), starting from CO.sub.2 and H.sub.2 by an integrated processing of Fischer-Tropsch raw products via different process steps with recycling of hydrogen or hydrogen-containing gases remaining after the processing into the RWGS before the Fischer-Tropsch synthesis.

Claims

1.-12. (canceled)

13. An installation for the production of standard-compliant fuels, wherein the installation comprises A) an optional unit for providing a CO.sub.2/H.sub.2 mixture B) a Fischer-Tropsch synthesis unit comprising or consisting of: at least one RWGS (Reverse Water Gas Shift Reaction) stage configured for a reaction of CO.sub.2 and H.sub.2 to synthesis gas, at least one Fischer-Tropsch stage configured for a reaction of CO and H.sub.2 in a Fischer-Tropsch synthesis, C.sub.0) optionally at least one discharge device for product streams originating from the Fischer-Tropsch synthesis, C) a processing unit configured for receiving and processing Fischer-Tropsch products discharged from the Fischer-Tropsch synthesis unit, comprising or consisting of at least one of the following three subunits: i) an isomerization unit, ii) a cracking unit iii) a hydrogenation unit, optionally at least one separation unit, at least one feed line for hydrogen, one or more discharge lines, each configured for a discharge of a fraction containing a standard-compliant fuel in each case, optionally one discharge line for an aqueous phase, and at least one discharge line for formed gases comprising hydrogen and C.sub.1- to C.sub.4-hydrocarbons, the at least one discharge line for the formed gases being designed as a recycle line for the gases into the RWGS stage, and wherein the installation does not have a purification device for the gases formed in the processing unit which are recycled to the RWGS stage.

14. The installation of claim 13, wherein the Fischer-Tropsch products discharged from the synthesis unit comprise a wax phase and an oil phase.

15. The installation of claim 13, wherein cracking unit ii) is a hydrocracking unit.

16. The installation of claim 13, wherein the installation is arranged on a single site.

17. The installation of claim 13, wherein the installation is arranged in a single housing.

18. The installation of claim 13, wherein the processing unit comprises at least two of the units i), ii) and iii).

19. The installation of claim 13, wherein the processing unit comprises all three of the units i), ii) and iii).

20. The installation of claim 13, wherein the installation is configured to produce at least one of kerosene, diesel or gasoline as a product.

21. The installation of claim 13, wherein the processing unit C) for the processing of wax phase and oil phase comprises or consists of the following installation parts, the respective installation parts being in operative connection with each other: C-A) feed lines for C-Aa) a wax phase, C-Ab) an oil phase, C-Ac) hydrogen; C-B) a hydrocracking reactor unit, which may consist of one or more sub-units, configured for the reaction of wax phase with hydrogen; C-C) one or more separation units configured for separation of product of unit C-B) into C-Ca) a long chain waxy fraction C-3a), C-Cc) a short-chain oily fraction C-3c), and C-Cd) hydrogen or hydrogen-containing gases C-3d); C-D) a mixing unit configured for mixing of oil phase with the short-chain oily fraction C-3c), C-E) one or more separation units configured for separating a mixture obtained in mixing unit C-D) into 5a) a long-chain, waxy fraction, 5c) a short-chain, fraction which can be discharged as a product, 5d) a medium-chain fraction, comprising Ea) a return line for fraction C-5a) to the wax phase, Ec) a discharge line for fraction C-5c) Ed) a discharge line for fraction C-5d); C-F) an isomerization and hydrogenation unit configured for reacting fraction C-5d) with addition of hydrogen, C-G) one or more separation units configured for separating a mixture obtained in unit C-F) into C-Ga) fuel and C-Gb) hydrogen or hydrogen-containing gases, the installation being configured to recycle hydrogen-containing gases formed in C-C) and C-G) into the RWGS stage of Fischer-Tropsch synthesis unit B).

22. The installation of claim 13, wherein a hydrogen feed line is arranged in Fischer-Tropsch synthesis unit B) between the RWGS stage and the Fischer-Tropsch stage.

23. A process for the production of standard-compliant fuels, wherein the process comprises: A) providing a CO.sub.2/H.sub.2 mixture, B) feeding the CO.sub.2/H.sub.2 mixture into a Fischer-Tropsch synthesis unit, reaction of CO.sub.2 and H.sub.2 to CO and H.sub.2 in a RWGS reaction, reaction of CO and H.sub.2 in a Fischer-Tropsch synthesis, C.sub.0) optionally discharging one or more product streams from the Fischer-Tropsch synthesis, and C) receiving and processing Fischer-Tropsch products discharged from the Fischer-Tropsch synthesis which were not discharged in C.sub.0), with the addition of hydrogen by at least one of the following reactions: i) isomerization, ii) cracking iii) hydrogenation, optionally separation, discharging of at least one fraction containing a standard-compliant fuel, optionally discharging of aqueous phase, and discharging of gases formed in processing, comprising hydrogen and C.sub.1- to C.sub.4-hydrocarbons, the discharging of gases formed in processing being carried out as recycle into the RWGS reaction, and the gases formed in the processing unit being recycled to the RWGS reaction without purification.

24. The process of claim 23, wherein processing of wax and oil phase discharged from the Fischer-Tropsch synthesis as Fischer-Tropsch products in C) comprises or consists of: Ia) providing the wax phase, optionally in a feed vessel, II) introducing the wax phase together with hydrogen into a hydrocracking reactor and converting the wax phase into shorter chain hydrocarbons, III) separating product obtained in II) into 3a) a long-chain waxy fraction, which is recycled to Ia), 3c) a short-chain oily fraction, 3d) hydrogen or hydrogen-containing gases, IV) providing an oil phase, optionally in a feed vessel, and mixing the oil phase with the short-chain oily fraction from 3c), optionally with simultaneous, at least partial, degassing, V) separating a mixture obtained in IV) into 5a) a long-chain, waxy fraction, which is recycled to Ia), 5c) a short-chain fraction which can be discharged as a product, 5d) a medium chain fraction, VI) reaction of fraction 5d) with addition of hydrogen in an isomerization and hydrogenation unit, VII) separation of product from VI) into 7a) fuel 7b) hydrogen or hydrogen-containing gases, the hydrogen-containing gases formed in III) and VII) being recycled.

25. The process of claim 23, wherein all process steps are carried out on a single site.

26. The process of claim 23, wherein all process steps are carried out in a single housing.

27. The process of claim 23, wherein C) comprises at least two of reactions i), ii) and iii).

28. The process of claim 23, wherein C) comprises all three reactions i), ii) and iii).

29. The process of claim 23, wherein the process is carried out such that at least one of kerosene, diesel or gasoline is obtained as a product.

30. The process of claim 23, wherein in B) a hydrogen feed is performed between a reaction of CO.sub.2 and H.sub.2 to CO and H.sub.2, in a RWGS reaction, and a reaction of CO and H.sub.2 in a Fischer-Tropsch synthesis.

Description

DESCRIPTION OF THE DRAWINGS

[0222] The present invention is explained in more detail below with reference to the drawings. The drawings are not to be construed as limiting and are not to scale. Furthermore, the drawings do not contain all the features that are present in usual installations, but are reduced to the features that are essential for the present invention and its understanding.

[0223] FIG. 1 shows schematically the present invention. CO.sub.2 and H.sub.2 as feed gas A are converted into Fischer-Tropsch products in a synthesis unit 1. In the example shown, the synthesis unit 1 schematically consists of an RWGS 2 and the actual Fischer-Tropsch installation 3. In the RWGS 2, CO.sub.2 and H.sub.2 are converted to synthesis gas, i.e. to CO and H.sub.2, whereby the by-products CO.sub.2 and H.sub.2O can also be present in the product gas. CO and H.sub.2, in turn, are then converted in the FT installation 3 to a product mixture B of gas phase consisting of non-converted synthesis gas (mainly CO, H.sub.2), short-chain hydrocarbons and volatile components of the by-products as well as CO.sub.2, a waxy phase of long-chain hydrocarbons that is solid at ambient temperature and pressure (wax phase), a hydrophobic phase of shorter-chain hydrocarbons (oil phase) which is liquid at ambient temperature and ambient pressure, and an aqueous phase of reaction water forming and organic compounds dissolved therein. This product mixture B (FT product) is then fed into the processing unit 4. As indicated in the figure, it is possible to branch off a part of the FT product B in the process. This branched-off part C can comprise entireties of the four phases mentioned or only parts. For example, it is possible to branch off a part of the oil phase or the entire oil phase, if this phase is intended for a specific use, and to feed the remainder into the processing unit 4. In the processing unit 4, the FT product B can then be processed by carrying out isomerisation, cracking, hydrogenation and separation/separation. For this purpose, hydrogen is fed F to the processing unit 4. At least one standard-compliant liquid fuel D is then discharged from the processing unit 4. The hydrogen-containing gas stream E formed in the processing unit 4, which may still contain C.sub.1- to C.sub.4-hydrocarbons, is recycled to the synthesis unit 1, there the RWGS unit 2, without further purification. By the recycling of the hydrogen-containing stream E, considerably less hydrogen is required than in a procedure according to the state of the art.

[0224] FIG. 2a shows the previous state of the art. In contrast to the present invention, the PtL site and the refinery are locally separated from each other (symbolised by two dashed boxes, the upper one representing the PtL site, the lower one the refinery). In the upper box the PtL site is illustrated, to which a synthesis unit 1 according to FIG. 1 is located, and in the upper box the refinery, where a processing unit 4 according to FIG. 1 is located. Hydrogen A1 and carbon dioxide A2 are introduced into the synthesis unit and as products (among others) oil phase B1 and wax phase B2 are obtained. These two phases B1 and B2 are processed in the processing unit 4 and the product D is obtained. According to the state of the art, as illustrated in FIG. 2a, due to the spatial separation of the PtL site and the refinery, there is no equipment connection between synthesis unit 1 and reprocessing unit 4. As a result, all of the hydrogen A1 required for synthesis unit 1 must be made available on site at the PtL site and, in addition, all of the hydrogen A1-II required for processing must be made available at the refinery site. Furthermore, the hydrogen formed during processing must be discharged and disposed of (e.g. incinerated) via a discharge line G at the refinery site.

[0225] FIG. 2b shows the same basic set-up as FIG. 2a, but in the arrangement according to the present invention. The basic reactions that take place in the units are essentially the same, as are the gas flows supplied to and discharged from the respective units. The difference to the prior art, however, is that the PtL site in addition to the synthesis unit 1 includes the processing unit 4, and this is not at a different location, the refinery (symbolised by a large dashed box encompassing both units). This makes it possible to recycle the hydrogen formed in the processing unit 4 directly into the synthesis unit as a recycling stream E. This has two enormous advantages: on the one hand, it reduces the amount of hydrogen required and on the other hand, the hydrogen formed during processing does not have to be disposed of. Thus, enormous ecological, economic and technical advantages are achieved.

[0226] A comparison of FIGS. 2a and 2b shows that of a total hydrogen demand of 163.6 kg/h hydrogen (127+36.6) per 1000 kg/h CO.sub.2 according to the state of the art 27.3 kg/h must be discharged and disposed of unused, which is recycled and continued to be used in the present invention. In this respect, by the present invention a hydrogen saving of around 17% is achieved.

[0227] FIG. 3 shows a possible variant of the processing of the FT products.

[0228] In this example, both the wax phase B2 and the oil phase B1 are temporarily stored in storage tanks ST2/ST1. The oil phase B1 can be degassed in the storage vessel ST1 (at any time), if this becomes necessary (not shown). The wax phase B2, or a certain portion thereof, is then fed into a hydrocracking reactor HC where it is converted with feeding of hydrogen from the hydrogen supply A1-II. The product then enters a hot separator HT, where a separation takes place and one phase is fed back into the storage vessel ST2 and the other further into a cold separator CT1. In the cold separator CT1, a separation takes place into a gas stream containing hydrogen, which is recycled as recycling stream E, and a fraction, which is fed into the aforementioned storage vessel ST1 of the oil phase B1. From this storage vessel ST1, the mixture of substances is fed into a separation unit S1. The bottom product obtained there is returned to the storage vessel ST2 for the wax phase and the head product is fed on into another separation unit S2. In this example, its head product is discharged as naphtha, i.e. as product D1. The bottom product of the second separation unit S2 is in this example fed into an isomerisation reactor I, where it is converted with the addition of hydrogen from the hydrogen supply A1-II. The product thus obtained is passed to a cold separator CT2, where a separation into hydrogen-containing gas—which is recycled as recycling stream E—and fuel, which is discharged as product D2, takes place.

[0229] It should be noted that the arrangement of the installation components shown in FIG. 3 is only one possibility, but it is not the only one.

[0230] FIG. 4 shows a graphical plotting of the material flows according to Example 2.

LIST OF REFERENCE SIGNS

[0231] 1 synthesis unit [0232] 2 RWGS unit [0233] 3 FT installation [0234] 4 processing unit [0235] A gas supply containing hydrogen and carbon dioxide gas [0236] A1 hydrogen supply [0237] A2 carbon dioxide supply [0238] A1-II hydrogen supply for processing [0239] B FT product [0240] B1 oil phase [0241] B2 wax phase [0242] C finished FT product (directly from 1) [0243] D product (standard-compliant fuel) [0244] D1 naphtha [0245] D2 JetFuel (fuel) [0246] E recycling stream containing hydrogen and C.sub.1- to C.sub.4-hydrocarbons [0247] G hydrogen discharge [0248] I isomerization unit [0249] S1 separation unit 1 [0250] S2 separation unit 2 [0251] CT1 cold separator 1 [0252] CT2 cold separator 2 [0253] HC hydrocracking reactor [0254] HT hot separator [0255] ST1 storage tank 1 [0256] ST2 storage tank 2