US-12617679-B2 - Chemical synthesis plant

US12617679B2US 12617679 B2US12617679 B2US 12617679B2US-12617679-B2

Abstract

A plant, such as a hydrocarbon plant, is provided, which consists of a syngas stage for syngas generation and a synthesis stage where said syngas is synthesized to produce syngas derived product, such as hydrocarbon product. The plant makes effective use of various streams; in particular CO 2 and H 2 . A method for producing a product stream, such as a hydrocarbon product stream is also provided.

Inventors

Sudip DE SARKAR
Martin Østberg
Thomas Sandahl Christensen
Kim Aasberg-Petersen

Assignees

HALDOR TOPSØE A/S

Dates

Publication Date: 20260505
Application Date: 20200403
Priority Date: 20190408

Claims (19)

1 . A method for producing a product stream, said method comprising the steps of: providing a plant, said plant comprising: a. a syngas stage, said syngas stage comprising an autothermal reforming (ATR) section; and b. a synthesis stage, said plant further comprising: a first feed comprising hydrogen to the syngas stage; a second feed comprising carbon dioxide to the syngas stage; a third feed comprising hydrocarbons to the syngas stage, upstream of said ATR section, said third feed being external to the plant; and a fourth feed comprising oxygen to the ATR section, wherein said syngas stage is arranged to provide a syngas stream and feed said syngas stream to the synthesis stage, supplying a first feed comprising hydrogen to the syngas stage; supplying a second feed comprising carbon dioxide to the syngas stage; supplying a third feed comprising hydrocarbons to the syngas stage, upstream of said ATR section; supplying a fourth feed comprising oxygen to the ATR section; providing a syngas stream in said syngas stage from at least said first, second, third and fourth feeds; feeding said syngas stream to the synthesis stage; and converting said syngas stream into at least a product stream and a hydrocarbon-containing off-gas stream in said synthesis stage, wherein the ratio of moles of carbon in the third feed comprising hydrocarbons to the moles of carbon in CO 2 in the second feed is less than 0.5.
2 . The method according to claim 1 , wherein the ratio of moles of carbon in the third feed comprising hydrocarbons to the moles of carbon in CO 2 in the second feed is less than 0.3.
3 . The method according to claim 1 , further comprising the step of feeding at least a portion of said hydrocarbon-containing off-gas stream to the syngas stage in addition to said third feed comprising hydrocarbons, upstream of said ATR section.
4 . The method according to claim 1 , wherein the syngas stream at the inlet of said synthesis stage has a hydrogen/carbon monoxide ratio in the range 1.00-4.00.
5 . The method according to claim 1 , wherein the ratio of H 2 :CO 2 provided at a plant inlet is between 1.0-9.0.
6 . The method according to claim 5 , wherein the synthesis stage is an FT synthesis stage and the H 2 :CO 2 -ratio at the plant inlet is in the range of 3.0-7.0.
7 . The method according to claim 1 , wherein said syngas stage consists of said autothermal reforming (ATR) section, and wherein first, second, and fourth feeds are fed directly to said ATR section.
8 . The method according to claim 1 , wherein: the syngas stage additionally comprises a methanation section arranged upstream the ATR section; a part or all of the first feed is fed to the methanation section; a part or all of the second feed is fed to the methanation section; and a part or all of the third feed is fed to the syngas stage, upstream said methanation section or between said methanation section and said ATR section.
9 . The method according to claim 1 , wherein: the syngas stage additionally comprises a reverse water gas shift (rWGS) section upstream the ATR section wherein a part or all of the first feed is fed to the rWGS section; a part or all of the second feed is fed to the rWGS section; and a part or all of the third feed is fed to the syngas stage between said rWGS section and said ATR section.
10 . The method according to claim 1 , wherein: the syngas stage comprises a reverse water gas shift (rWGS) section arranged in parallel to said ATR section; at least a portion of the first feed and at least a portion of the second feed are arranged to be fed to the rWGS section and said rWGS section is arranged to convert said at least a portion of the first feed and at least a portion of the second feed to a first syngas stream; a third feed comprising hydrocarbons and a fourth feed comprising oxygen are arranged to be fed to the ATR section; said ATR section is arranged to convert said third feed comprising hydrocarbons and said fourth feed comprising oxygen to a second syngas stream; and the first syngas stream from the rWGS section is arranged to be combined with the second syngas stream from the ATR section; and the combined syngas stream is arranged to be fed to the synthesis stage.
11 . A plant, said plant comprising: a. a syngas stage, said syngas stage comprising an autothermal reforming (ATR) section; and b. a synthesis stage, said plant comprising: a first feed comprising hydrogen to the syngas stage; a second feed comprising carbon dioxide to the syngas stage; a third feed comprising hydrocarbons to the syngas stage, upstream of said ATR section, said third feed being external to the plant; and a fourth feed comprising oxygen to the ATR section, wherein said syngas stage is arranged to provide a syngas stream and feed said syngas stream to the synthesis stage, and wherein: the syngas stage additionally comprises a methanation section arranged upstream the ATR section; a part or all of the first feed is fed to the methanation section; a part or all of the second feed is fed to the methanation section; a part or all of the third feed is fed to the syngas stage, upstream said methanation section or between said methanation section and said ATR section, the synthesis stage has a product outlet and three different hydrocarbon-containing off-gas outlets, a first hydrocarbon-containing off-gas outlet being a first hydrocarbon-containing off-gas feed to the ATR section, a second hydrocarbon-containing off-gas outlet being a second hydrocarbon-containing off-gas feed to the methanation section, and a third hydrocarbon-containing off-gas outlet being a third hydrocarbon-containing off-gas feed to the methanation section.
12 . The method according to claim 1 , wherein said third feed comprising hydrocarbons is fed to the syngas stage, directly upstream of said ATR section.
13 . The method according to claim 1 , further comprising a fifth steam feed to the syngas stage.
14 . The method according to claim 1 , wherein said third feed comprising hydrocarbons is a natural gas feed.
15 . The method according to claim 1 , wherein the synthesis stage is a Fischer-Tropsch (F-T) stage arranged to convert said syngas stream into at least a hydrocarbon product stream and a hydrocarbon-containing off-gas stream in the form of an F-T tail gas stream.
16 . The method according to claim 1 , wherein the synthesis stage comprises a methanol synthesis stage arranged to provide at least a methanol product stream.
17 . The method according to claim 1 , further comprising an electrolyser arranged to convert water or steam into at least a hydrogen-containing stream and an oxygen-containing stream, and wherein at least a part of said hydrogen-containing stream from the electrolyser is fed to the syngas stage as said first feed and/or wherein at least a part of said oxygen-containing stream from the electrolyser is fed to the syngas stage as said fourth feed.
18 . The method according to claim 1 , further comprising providing a sixth feed comprising hydrogen to the syngas stream, upstream the synthesis stage.
19 . The method according to claim 1 , wherein: the syngas stage further comprises a methanation section arranged upstream the ATR section; and the synthesis stage has a product outlet and three different hydrocarbon-containing off-gas outlets, a first hydrocarbon-containing off-gas outlet being a first hydrocarbon-containing off-gas feed to the ATR section, a second hydrocarbon-containing off-gas outlet being a second hydrocarbon-containing off-gas feed to the methanation section, and a third hydrocarbon-containing off-gas outlet being a third hydrocarbon-containing off-gas feed to the methanation section, the process further comprising: feeding the first hydrocarbon-containing off-gas feed from the first hydrocarbon-containing off-gas outlet to the ATR section; feeding the second hydrocarbon-containing off-gas feed from the second hydrocarbon-containing off-gas outlet to the methanation section; and feeding the third hydrocarbon-containing off-gas feed from the third hydrocarbon-containing off-gas outlet to the methanation section.

Description

TECHNICAL FIELD The present invention relates to a plant, such as a hydrocarbon plant, with effective use of various streams, in particular carbon dioxide. A method for producing a product stream, such as a hydrocarbon product stream is also provided. The plant and method of the present invention provide overall better utilization of carbon dioxide. BACKGROUND Carbon capture and utilization (CCU) has gained more relevance in the light of the rise of atmospheric CO2 since the Industrial Revolution. In one way of utilizing CO2, CO2 and H2 can be converted to synthesis gas (a gas rich in CO and H2) which can be converted further to valuable products like alcohols (including methanol), fuels (such as gasoline, jet fuel, kerosene and/or diesel produced for example by the Fischer-Tropsch (F-T) process), and/or olefins etc. Existing technologies focus primarily on stand-alone reverse Water Gas Shift (rWGS) processes to convert CO2 and H2 to synthesis gas. The synthesis gas can subsequently be converted to valuable products in the downstream processes as outlined above. The reverse water gas shift reaction proceeds according to the following reaction: CO2+H2↔HCO+H2O (1) The rWGS reaction (1) is an endothermic process which requires significant energy input for the desired conversion. Very high temperatures are needed to obtain sufficient conversion of carbon dioxide into carbon monoxide to make the process economically feasible. Undesired by-product formation of for example methane may also take place. High conversions of carbon dioxide can evidently also be obtained by high H2/CO2-ratio. However, this will often result in a synthesis gas with a (much) too high H2/CO-ratio for the downstream synthesis. Technologies relying on the rWGS reaction have other challenges. In some cases, hydrocarbons may be available as co-feed. An example is the availability of hydrocarbons from a downstream synthesis stage (e.g. a propane and butane rich stream from an F-T stage; tail gas comprising different hydrocarbons from an F-T stage; naphtha stream from an F-T stage; propane and butane rich stream from a gasoline synthesis stage; a hydrocarbon stream from olefin synthesis etc.). Such hydrocarbons cannot be processed in an rWGS reactor. If the hydrocarbon streams from the downstream synthesis stage are not used at least in part for additional production of synthesis gas, the overall process may not be feasible from an economic point of view. The same is the case if a hydrocarbon stream, such as natural gas, is available as co-feed to the plant. To address problems with existing technologies, a novel process of syngas preparation and then, synthesis from the said syngas to syngas derived product(s) from primarily CO2, H2 and O2 feed is presented in this document. The proposed layout has at least the following advantages: 1. CO2, H2, and O2 can be converted to syngas with a desired H2:CO ratio, suitably without using any hydrocarbon feed to the plant. If needed, one or more hydrocarbon co-feed to the plant can be used as well.2. Utilization of any hydrocarbons generated in the synthesis stage for synthesis gas production3. A higher utilization of the carbon dioxide feed is possible compared to a stand-alone rWGS section. One particular aim is to utilize more CO2 feed instead of hydrocarbon feed as a source of carbon.4. Conversion of any hydrocarbon co-feed streams fed to the syngas stage is possible.5. If an electrolyzer is used as part or the entire source of the hydrogen feed to the process, part or all of the oxygen, generated in the electrolyzer along with H2, can be used as the oxygen source that is required in the proposed process layout. SUMMARY In a first aspect, therefore, a method for producing a product stream is provided. The method comprises the steps of: providing a plant, said plant comprising: a. a syngas stage, said syngas stage comprising an autothermal reforming (ATR) section, and;b. a synthesis stage; said plant comprising: a first feed comprising hydrogen to the syngas stage;a second feed comprising carbon dioxide to the syngas stage;a third feed comprising hydrocarbons to the syngas stage, upstream of said ATR section; anda fourth feed comprising oxygen to the ATR section; wherein said syngas stage is arranged to provide a syngas stream and feed said syngas stream to the synthesis stage (B); supplying a first feed comprising hydrogen to the syngas stage;supplying a second feed comprising carbon dioxide to the syngas stage;supplying a third feed comprising hydrocarbons to the syngas stage, upstream of said ATR section;supplying a fourth feed comprising oxygen to the ATR section;providing a syngas stream in said syngas stage from at least said first, second, third and fourth feeds, and feeding said syngas stream to the synthesis stage;converting said syngas stream into at least a product stream and a hydrocarbon-containing off-gas stream in said synthesis stage; wherein the ratio of moles of