PROCESS FOR CONVERTING METHANOL TO HYDROCARBONS SUITABLE FOR USE AS GASOLINE OR BLENDSTOCK

Abstract

The present application relates to a process for production of hydrocarbons comprising the steps of converting a feed stream comprising alcohols, ethers or mixtures hereof over a metal-containing zeolite based catalyst, active in dehydrogenation of hydrocarbons, in a conversion step thereby obtaining a conversion effluent, separating said effluent to obtain art aqueous process condensate stream, a liquid hydrocarbon stream and a gaseous stream, removing part of the hydrogen formed in the conversion step, and recycling at least part of the gaseous and/or liquid hydrocarbon stream to the conversion step.

Claims

1. A process for production of a hydrocarbon product suitable for use as gasoline or as a blendstock, said process comprising the steps of converting a feed stream comprising alcohols, ethers or mixtures hereof over a metal-containing zeolite based catalyst, active in dehydrogenation of hydrocarbons, in a conversion step thereby obtaining a conversion effluent, separating said effluent to obtain an aqueous process condensate stream, a liquid hydrocarbon stream and a gaseous stream, removing part of the hydrogen formed in the conversion step, and recycling at least part of the gaseous and/or liquid hydrocarbon streams to the conversion step.

2. A process according to claim 1 wherein hydrogen is removed by purging at least part of the gaseous recycle stream.

3. A process according to claim 1, wherein the liquid hydrocarbon phase is separated into a product phase and one or more lower- and/or higher-boiling phases, at least one of which lower- and/or higher-boiling phases is at least partially recycled to the conversion step as the at least partly H.sub.2 depleted recycle.

4. A process according to claim 1, wherein the liquid hydrocarbon stream and/or product phase comprises raw gasoline, Stabilized gasoline or gasoline with an aromatics content below 40%, a hydrocarbon product suitable as blend stock.

5. A process according to claim 1, wherein the liquid hydrocarbon stream and/or product phase has a durene content below 6%.

6. A process according to claim 1, wherein the hydrocarbon product is a high octane gasoline blendstock.

7. A process according to claim 1, wherein at least part of the gaseous phase is recycled to the conversion step.

8. A process according to claim 1, wherein the conversion step takes place in two or more consecutive reactors.

9. A process according to claim 1, wherein the at least part of the recycle stream or recycle streams is returned to one or more points upstream the conversion step.

10. A process according to claim 1, comprising a step regulating the H.sub.2 content in the at least partly H.sub.2 depleted recycle stream.

11. A process according to claim 1, wherein the zeolite based catalyst is a single bifunctional catalyst catalysing both methanol to hydrocarbons and dehydrogenation.

12. A process according to claim 1, wherein the zeolite based catalyst comprises a mixture of two or more catalysts which in combination catalyse both methanol to hydrocarbons and dehydrogenation reactions.

13. A process according to claim 1, wherein the zeolite based catalyst comprises a metal and/or metal oxide and a zeolite.

14. A process according to claim 1, wherein catalyst comprises a zeolite and a metal selected from the group consisting of Zn, Ga, In, Mo, Ag, P, Ge, Sn, Pd and Pt.

15. A process according to claim 1, wherein the feed stream comprises methanol, dimethyl ether or mixtures hereof.

16. A process according to claim 1, wherein the process is carried out in one or more fixed bed reactors.

17. A process according to claim 1, wherein the process is carried out in one or more fluid bed reactors.

18. A process according to claim 1, wherein the dehydrogenation catalyst is arranged as a top and/or bottom layer in the conversion reactor and/or in one or more separate dehydrogenation reactors.

19. A plant for the conversion of methanol to hydrocarbons comprising aromatics, said plant comprising means for supplying a feed stream comprising methanol, dimethyl ether or mixtures hereof a conversion reactor a separator for separating a conversion effluent into a gaseous recycle stream, process condensate and a liquid product, means for removing H.sub.2 from at least part of the effluent thereby obtaining at least one at least partially H.sub.2 depleted recycle stream, and means for recycling the at least part of the effluent.

20. A plant for the conversion of methanol to hydrocarbons according to claim 19, wherein the means for removing H.sub.2 from at least part of the effluent obtaining at least one at least partly H.sub.2 depleted recycle stream is a selective membrane, a selective oxidation step and/or a step wherein a hydrogen scavenger is converted into methanol or water in the presence of H.sub.2 and a hydrogenation catalyst.

21. A plant for the conversion of methanol to hydrocarbons according to claim 19, wherein the means for removing H.sub.2 from at least part of the effluent obtaining at least one at least partly H.sub.2 depleted recycle stream comprises means for separating the liquid hydro carbon stream into at least a product phase and one or more lower- and/or higher-boiling phases and means for recycling at least one of said lower- and/or higher-boiling phases as the at least partly H.sub.2 depleted recycle.

22. Product obtained by any of the plant, process or catalyst according to claim 1.

23. Gasoline obtained by any of the plant or process according to claim 1.

24. Reformate blendstock obtained by any of the plant, process according to claim 1.

25. High octane gasoline blendstock obtained by any of the plant, process or catalyst according to claim 1.

Description

[0089] In the following the process and plant is further described with reference to the accompanying drawings. The drawings show exemplary embodiments of the present process and plant and are not to be construed as limiting to the scope of the present application.

[0090] FIG. 1 shows a schematic setup of a first embodiment according to the present invention;

[0091] FIG. 2 shows a schematic setup of a second embodiment according to the present invention;

[0092] FIG. 3 shows a schematic setup of third embodiment according to the present invention; and

[0093] FIG. 4 shows a schematic MTG setup according to the present invention.

[0094] FIG. 1 shows a schematic overview 1 of a plant/process according to the present application. A conversion effluent 2 is fed to a first separator 3 wherein the conversion effluent is separated into three streams: process condensate 4, first product stream (liquid Hydrocarbon stream) 5 and a gas stream 6.

[0095] The first product stream is fed to a second separator 7 wherein the first product stream is separated into a second product stream (product phase) 8 and a LPG stream comprising C3-C4 wherefrom the recycle stream 9a is taken.

[0096] As described herein the first product stream is near H.sub.2 free and H.sub.2 is present predominantly in the gas phase in the first separator. Thus when the first product stream is separated into the second product stream 8 and the recycle stream the recycle stream obtained is a H.sub.2 depleted recycle.

[0097] The second product stream 8 may be send to further processing, upgrade, storage etc.

[0098] FIG. 2 shows a schematic overview 10 of a plant/process according to the present application. A conversion effluent 2 is fed to a first separator 3 wherein the conversion effluent is separated into three streams: process condensate 4, first product stream 5 and a gas stream 6. At least part of the gas stream 6 is taken through a H.sub.2 depletion step 11 whereby a H.sub.2 depleted recycle stream 9b obtained.

[0099] The H.sub.2 depletion step 11 may comprise e.g. a H.sub.2 permeable membrane and/or a catalytic oxidation step.

[0100] FIG. 3 shows a schematic overview 12 of a plant/process wherein the embodiments of FIGS. 1 and 2 are combined whereby a H.sub.2 depleted stream is obtained from the gas stream 9b and from the LPG fraction taken from the second separator as H.sub.2 depleted stream 9a.

[0101] In the embodiments of FIGS. 1, 2 and 3 the one or more H2 depleted streams are returned to the conversion step (not shown) from which the conversion effluent 2 is obtained. The conversion step may be a MTG or a MTA process.

[0102] FIG. 4 shows a schematic overview 12 of a MTG plant/process according to the present application. A conversion effluent 2 is fed to a first separator 3 wherein the conversion effluent is separated into three streams: process condensate 4, first product stream (liquid hydrocarbon stream) 5 and a gas stream 6. Here the liquid hydrocarbon stream is raw gasoline as the process is MTG.

[0103] The raw gasoline is fed to one or more separators 7 here illustrated by a single separator. In the one or more separator steps the first product stream/raw gasoline is separated into a second product stream which in this case may be gasoline or stabilized gasoline 8 and a LPG stream comprising C3-C4 wherefrom the at least partly H.sub.2 depleted recycle stream 9a is taken. From the one or more separation steps 7 one or more additional streams may be obtained including a heavy oil stream 13 containing products with higher boiling point than final boiling point specs for the gasoline.

[0104] The raw gasoline 5 contains only little H.sub.2 as H.sub.2 is present predominantly in the gas phase in the first separator. Thus when the first product stream is separated into the second product stream 8 and the recycle stream, the recycle stream obtained is a H.sub.2 depleted recycle. Any H.sub.2 present in the raw gasoline may be removed as part of a light fraction stream 14 further comprising e.g. CH.sub.4, CO and CO.sub.2.

[0105] The second product stream 8 may be send to further processing, upgrade, storage etc.