Distillation with vapor recompression

Abstract

The present invention relates to a system for distillation, specifically a system for distillation of a first raw product stream, preferably a raw methanol stream. The invention further relates to a method for distillation of a first raw product stream and to a chemical plant.

Description

[0001] DISTILLATION WITH VAPOR RECOMPRESSION

[0002] TECHNICAL FIELD

[0003] The present invention relates to a system for distillation, specifically a system for distillation of a first raw product stream, preferably a raw methanol stream. The invention further relates to a method for distillation of a first raw product stream and to a chemical plant.

[0004] BACKGROUND

[0005] Reboilers are heat exchangers typically used to provide heat to industrial distillation columns (typically the bottom thereof). In a typical classical distillation column, most - if not all - the vapour driving the separation comes from the reboiler. The reboiler receives a liquid stream (i.e., a take-off stream) from the column bottom and may partially or completely vaporize it. Following vaporisation, the stream is returned to the column to drive the distillation process. The heat required for the reboiler is usually provided by low pressure steam streams. In traditional chemical plants such low-pressure streams may be generated as side product streams during chemical synthesis.

[0006] In recent years, the development of chemical plants and processes strives towards production which enables renewable energy sources to drive production of chemical compounds. One way of achieving this is to use an e-syngas section which through electrolysis of water and / or carbon dioxide can provide an e-syngas, which is suitable for further synthesis of carbon comprising chemical compounds. Within such renewable chemical plants, production of chemical compounds does not necessarily provide a sufficient amount of low-pressure steam to supply the necessary energy to drive the distillation process for achieving the high-grade purified product stream, such as a high grade purified methanol stream.

[0007] In addition, in relation to existing traditional chemical production plants, an overall reduction of energy consumption of the chemical plant is desirable as such reduction typically also results in an overall lowering of the carbon emissions from said plant. In this way, there is a need to reduce the energy consumption in a system for distillation, such as in a distillation system in a chemical plant. Additionally, there may be a need for providing a more flexible heat supply to achieve energy optimization within said system for distillation such as within a chemical plant. SUMMARY

[0008] It has been found by the present inventor(s) that the first product stream provided from a first concentration column holds the potential for introducing additional energy into the production process. To exploit this, a first compressor is arranged to receive at least a portion of the first product stream and a pure product stream, pressurise said stream, and provide a second product stream having heat energy that can be arranged to be used for driving the distillation processes in the first column and optionally in the processes in the stabilizer section.

[0009] So, in a first aspect the present invention relates to a system for distillation, said system comprising : a first raw product stream; a stabilizer section comprising a stabilizer column; a first concentration column; a first compressor; a first reboiler; a cooling arrangement; a drum; wherein the stabilizer section is arranged to receive the first raw product stream and provide a second raw product stream, and a first off-gas stream; wherein the first concentration column is arranged to receive the second raw product stream and distil said stream so as to output a first product stream, a first condensate stream, and optionally a second off-stream; wherein the first compressor is arranged to receive at least a portion of the first product stream and a pure product stream so as to output a second product stream; wherein the first reboiler is arranged to receive at least a portion of the second product stream and provide heat energy to the first concentration column, and wherein at least a portion of the heat energy for the first reboiler is provided from the second product stream such that said first reboiler outputs a cooled third product stream; wherein the cooling arrangement is arranged to receive at least a portion of the cooled third product stream and provide a further cooled product stream; wherein the drum is arranged to receive at least a portion of the further cooled product stream and provide a first distilled product stream.

[0010] Specifically, the system for distillation may be used in a chemical plant. Hence, in a second aspect, the present invention relates to a chemical plant comprising : a syngas stream; a product synthesis section; the system for distillation according to the system disclosed herein, wherein said product synthesis section is arranged to receive at least a portion of said syngas stream and output a first raw product stream, and wherein said system for distillation is arranged to receive said first raw product stream from said product synthesis section and provide a first distilled product stream such as a second portion of said first distilled product stream.

[0011] In a third aspect, the present invention relates to a method for distillation of a first raw product stream in a system according to the system disclosed herein is provided, wherein said method comprises: feeding a first raw product stream to the stabilizer section and providing a second raw product stream, and a first off-gas stream; feeding at least a portion of the second raw product stream to the first concentration column, distilling said stream and providing a first vaporised product stream from said first concentration column, a first condensate stream, and optionally a second off- stream; feeding at least a portion of the first product stream and a pure product stream to the first compressor, and providing a second product stream from said first compressor; feeding at least a portion of the second product stream to the first reboiler, and hereby providing heat energy to the first concentration column, wherein the step of providing heat energy to the first concentration column comprises providing heat energy from at least a portion of the second product stream to the first reboiler and providing a cooled third product stream from said first reboiler; feeding at least a portion of the third product stream to the cooling arrangement to provide the further cooled product stream; feeding at least a portion of the further cooled product stream to the drum to provide a first distilled product stream.

[0012] In a fourth aspect the present invention relates to a system for distillation, said system comprising : a second raw product stream; a first concentration column; a first compressor; a first reboiler; wherein the first concentration column is arranged to receive the second raw product stream and distil said stream so as to output a first product stream, a first condensate stream, and optionally a second off-stream; wherein the first compressor is arranged to receive at least a portion of the first product stream and a pure product stream so as to output a second product stream; wherein the first reboiler is arranged to receive at least a portion of the second product stream and provide heat energy to the first concentration column, and wherein at least a portion of the heat energy for the first reboiler is provided from the second product stream such that said first reboiler outputs a cooled third product stream.

[0013] The system may be provided in a new chemical plant or the system may be provided to an existing plant, i.e. a revamp.

[0014] In a fifth aspect the present invention relates to a method of revamping an existing distillation system. The method comprising : providing a first compressor configured to receive at least a portion of a first product stream from a first concentration column and pure product stream and output a second product stream, fluidly connect the first compressor to a first concentration column of the distillation system, fluidly connect the first compressor to a pure product stream of the distillation system, fluidly connect an outlet of the first compressor to a first reboiler of the distillation system.

[0015] Further details of the system, the method for distillation, and the related plants, are specified in the following detailed description, figures, and claims.

[0016] LEGENDS

[0017] Fig. 1 shows a first schematic drawing of the system and method for distillation.

[0018] Fig. 2 shows a second schematic drawing of the system for distillation.

[0019] Fig. 3 shows a third schematic drawing of the system for distillation. Fig. 4 shows a fourth schematic drawing of the system for distillation.

[0020] Fig. 5 shows a fifth schematic drawing of the system for distillation.

[0021] Fig. 6 shows a sixth schematic drawing of the system for distillation.

[0022] Fig. 7 shows a seventh schematic drawing of the system for distillation.

[0023] Fig. 8 shows a first schematic drawing of the first compressor.

[0024] Fig. 9 shows a first schematic drawing of the chemical plant.

[0025] DETAILED DISCLOSURE

[0026] Unless otherwise specified, any given percentages for gas content are % by volume. The terms "synthesis gas" and "syngas" are used interchangeably in this text.

[0027] System for distillation

[0028] A system for distillation comprises a first raw product stream; a stabilizer section comprising a stabilizer column; a first concentration column; a first compressor, a first reboiler, a cooling arrangement; and a drum.

[0029] The first raw product stream

[0030] The first raw product stream may be a raw methanol stream, wherein said raw methanol stream comprises methanol (MeOH). The raw methanol stream may further comprise water (H2O), higher alcohols, such as ethanol and propanol, and light impurities comprising ketones, and dissolved gases, such as CO2. Typically, the raw methanol stream comprises methanol in a concentration of 60-70% by weight if based on above-mentioned e-syngas. Alternatively, the first raw product stream could also originate from syngases based on reforming of biogas or natural gas or gasification of coal. In this way, the first raw product stream may be a raw methanol stream, and the first distilled product stream may be a distilled methanol stream. The stabilizer section

[0031] The stabilizer section is arranged to receive the first raw product stream and provide a second raw product stream, and a first off-gas stream.

[0032] The stabilizer section removes gases and other light impurities. The stabilizer section is arranged to provide a second raw product stream, which is a purified stream relative to the first raw product stream. Typically, when the first raw product stream is a raw methanol stream, the second raw product stream comprises methanol 60-70 weight%, water 30-40 weight%, ketones less than 500 weight ppm, higher alcohols 500 weight ppm. When the first raw product stream is a raw methanol stream, the first off-gas stream may comprise approx. 80% CO2and 20% methanol.

[0033] The stabilizer section comprises a stabilizer column, typically said column being arranged to provide the second raw product stream. A series of energy-providing arrangements may be implemented to drive the stabilization process. Such arrangement may comprise heaters or a transfer of heat energy from a low-pressure steam stream to the bottom of the stabilizer column via a reboiler. More specifically, wherein a reboiler is arranged to provide heat energy to the stabilizer column, said reboiler may receive a take-off stream from the stabilizer column and provide a return stream arranged to be fed to the stabilizer column. Herein, a take-off stream is a liquid take-off stream arranged to be provided from a column and a return stream is a vapour return stream (e.g. comprising vapour) arranged to be returned to the column. Hence, said reboiler may provide the energy required to drive the stabilization process of the first raw product stream.

[0034] The stabilizer section may further comprise an internal first vapor stream, an internal condenser heat exchanger for condensing the internal first vapor stream, an internal drum, and an internal pump. Preferably, the stabilizer column is arranged to provide the internal first vapor stream directly from the top of the column, the internal condenser heat exchanger is arranged to receive at least a portion of the internal first vapor stream and condense said stream to provide an internal condensed stream. The internal drum is arranged to receive at least a portion of the internal condensed stream to provide a first off-gas stream (such as the first off-gas stream provided from the stabilizer section) and a liquid stream, wherein at least a portion of (preferably all of) said liquid stream is arranged to be refluxed to the stabilizer column via the internal pump. The first concentration column

[0035] The first concentration column is arranged to receive the second raw product stream and distil said stream so as to output a first product stream, a first condensate stream, and optionally a second off-stream. The first concentration column is a column suitable for distillation, preferably a column suitable for methanol distillation. Generally, a concentration column is understood to comprise a series of equilibrium stages in which two phases establishes an equilibrium. The concept of equilibrium stages is well known in the art.

[0036] The first concentration column may be a low-pressure distillation column. Typically, the operation pressure of the first concentration column may be between 0.1-10.0 bar g, preferably 0.1-1.5 bar g. Herein operation pressure refers to a pressure measured within any equilibrium stage within said column. The operation temperature interval within the first concentration column may vary dependent on the product desired to be distilled. Suitably, a column for methanol distillation is operated within a temperature interval between 68-125 °C, wherein the temperature interval refers to a temperature measured within any equilibrium stage within said column.

[0037] The first product stream comprises vaporised product, such as 95% product, or preferably 99% product. This first product stream may thus consist essentially of methanol such as preferably be 99% methanol. The second off-stream comprises methanol, water and higher alcohols. Typically, the second off-stream is a liquid stream. The first condensate stream may be a first distillation water stream, preferably comprising more than 95 weight% water with traces of product such as traces of methanol.

[0038] To drive the distillation processes in the first column, the system comprises the first compressor and the first reboiler. The first compressor is arranged to receive at least a portion of the first product stream and a pure product stream so as to output a second product stream. The pure product stream is used to refer to a product stream which essential comprises product such as 60wt% product, however preferably above 90wt% product such as above 95wt% product, more preferably above 98wt% product most preferably 99wt% product or above 99wt% product. Most preferably, the pure product stream has a purity equal to or above the first distilled product stream, such as the first product stream, wherein purity is to be understood as wt% product such as wt% methanol of said stream. The pure product stream may be fuel grade methanol or AA grade methanol or equivalent standards. Specifically, the pure product stream arranged to be received by the first compressor may comprise at least a first portion of the first distilled product stream provided from the drum. Additionally, at least a second portion of the first distilled product stream may be provided from said system for distillation. Said second portion of the first distilled product stream may be a final product stream arranged to be sent to storage such as to a storage tank. Additionally, or alternatively, the pure product stream arranged to be received by the first compressor may comprise a pure product stream from storage such as from a product storage tank e.g. a methanol storage tank.

[0039] The first compressor is responsible for compressing at least a portion of the first product stream and to output a second product stream. The first reboiler is arranged to receive at least a portion of the second product stream and provide heat energy to the first concentration column, and wherein at least a portion of the heat energy for the first reboiler is provided from the second product stream such that said first reboiler outputs a cooled third product stream. Preferably, the second product stream is a compressed and superheated vapor that is cooled to saturation point and condensed at that temperature in the first reboiler.

[0040] The first reboiler is arranged to provide at least a portion of the necessary energy for driving the distillation within the first concentration column. The first reboiler may be a reboiler providing heat energy to the bottom of the column, i.e. providing heat energy to the lowest equilibrium stage. At the lowest equilibrium stage, the temperature is higher than all equilibrium stages above, as the temperature decreases going up through the column. Alternatively, the first reboiler may be a side-drawn reboiler arranged to provide heat energy to minimum one equilibrium stage above the lowest equilibrium stage. Preferably, the first reboiler is arranged to provide heat energy to the bottom of the column. Specifically, the first reboiler may be arranged such that said first reboiler receives a first take-off stream from the first concentration column and provides a first return stream, arranged to be fed to the first concentration column. In this way, the first reboiler may vaporise essentially all the liquid of the take-off stream to provide a vapor return stream or alternatively the first reboiler may vaporise a portion of the liquid of the take-off stream to provide a vapor return stream and a liquid return stream. In this way, a first reboiler provides heat to a take-off stream such that at least a portion of the heat energy for the first reboiler is provided from the second product stream.

[0041] Alternatively or additionally, the first reboiler may be arranged to provide heat energy to at least a portion of the second raw product stream from the stabilizer section. This is an alternative way of providing heat energy to the first concentration column. One way of achieving this may be to split the second raw product stream in a first stream comprising at least a portion of the vaporised portion of the second raw product stream and a second stream comprising at least a portion of the liquid portion of the second raw product stream, wherein the first reboiler is arranged to provide heat energy to the second stream, such to vaporise at least a portion of the second stream and provide a third stream, wherein the first stream and the third stream is fed as feeds to the first concentration column as separate streams, or preferably as a combined stream. Another way of providing heat energy to the first concentration column is to provide heat energy to the second raw product stream from the stabilizer section to provide a first stream comprising a vapor stream, and optionally a second stream comprising a liquid stream, and feed the first stream and optionally also the second stream to the first concentration column.

[0042] Preferably, all the required energy for driving the distillation process within the first reboiler may be provided from the second product stream. This allows for the system for distillation to be driven only on heat energy provided by the compressor, hence on renewable energy.

[0043] Cooling arrangements and the first distilled product stream

[0044] The first reboiler outputs a cooled third product stream, which may still comprise excess heat energy. The cooling arrangement is arranged to receive at least a portion of the cooled third product stream and provide a further cooled product stream. Suitably, the cooled third product stream may be of a temperature of 110-140 °C such as 120-140 °C. The cooling arrangement allows for a suitable further cooled product stream to be received by the drum. Additionally, the cooling arrangement specifically allows for optimised heat integration such to allow for excess heat energy available within the system to be arranged to be used for driving the distillation. Preferably, the cooling arrangement comprises one or more reboilers and / or one or more heat exchangers, most preferably arranged in series.

[0045] The cooling arrangement may comprise means for cooling arranged to provide at least a portion of the further cooled product stream suitable for being received by the drum. Such means for cooling may be a unit, which allows for providing a stream such as a further cooled product stream being within a specific temperature range and / or pressure range. Typically, when the first raw product stream is a raw methanol stream, the further cooled product stream has a temperature in the range of 60-70°C, such as of 65°C. Suitably, said further cooled product stream may have a pressure in the range of -0.2 to 9.0 bar g.

[0046] Specifically, the cooling arrangement may comprise means for cooling comprising a first heat exchanger wherein said first heat exchanger is arranged to provide at least a portion of the further cooled product stream. Hence, the cooling arrangement may comprise means for cooling such as a first heat exchanger arranged to provide a further cooled product stream having a temperature in the range of 60-70°C, such as of 65°C. The first heat exchanger may further be arranged to receive at least a portion of the cooled third product stream and / or at least a portion of one or more stream(s) derivable from said cooled third product stream. Herein the term "stream(s) derivable from the cooled third product stream" refers to streams that are in the feed route to at least a portion of the cooled third product stream. In this way, the system may further comprise a first heat exchanger, wherein said first heat exchanger is arranged to receive at least a portion of the cooled third product stream or at least a portion of one or more stream(s) derivable from the cooled third product stream and provide at least a portion of the further cooled product stream.

[0047] Additionally, or alternatively, the cooling arrangement may comprise means for cooling comprising connections for adding a cooling liquid, such as a cooling liquid having a temperature lower than the cooled third product stream. Typically, when the first raw product stream is a raw methanol stream, such cooling liquid is suitably comprising methanol. Hence, said cooling liquid may be a further cooled portion of the first distilled product stream such as a portion of the first distilled product stream having been cooled below the temperature of the cooled third product stream, preferably below 65°C.

[0048] Preferably, any means for cooling is arranged to provide the further cooled product stream from the cooling arrangement. In other words, the means for cooling is preferably arranged as a last temperature regulating unit within the cooling arrangement such as preferably being the last unit prior to the drum. Herein a "temperature regulating unit" is used to refer to a unit suitable for changing the temperature / pressure of a gas or liquid. In this way, preferably, the cooling arrangement allows for a suitable further cooled product stream to be received by the drum, hence provide a possibility for tuning the temperature / pressure of the further cooled product stream.

[0049] Additionally, or alternatively, the cooling arrangement may comprise one or more heat integration units, said heat integration units being arranged to transfer heat energy from the cooled third product stream and / or from streams derivable from said cooled third product stream to one or more product streams or take-off streams within the system for distillation. Hence, the cooling arrangement may allow excess heat energy comprised in the cooled third product stream, or excess heat energy comprised in one or more stream(s) derivable from the cooled third product stream, to be arranged to provide heat energy to one or more stream(s) such as by the excess heat energy being transferred via heat exchange. The excess heat energy is thus not wasted in air cooler and / or water cooler. In this way, the cooling arrangement may allow for all the required energy for driving the distillation process to be provided from the second product stream such as allow for both the stabilizer column as well as the first concentration column to be driven only on heat energy provided by the compressor, hence on renewable energy.

[0050] The cooling arrangement may comprise one or more heat integration unit(s) being one or more reboilers and / or one or more heat exchangers. Specifically, the cooling arrangement may comprise a second reboiler. More specifically, the system may further comprise a second reboiler, wherein the second reboiler is arranged to receive at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream and said second reboiler is arranged to provide heat energy to the stabilizer column, wherein at least a portion of the heat energy for the second reboiler is provided from the cooled third product stream and / or from the at least a portion of a stream derivable from said cooled third product stream.

[0051] The system may be arranged with the cooling arrangements specifically, comprising a second reboiler and means for cooling such as first heat exchanger, wherein the second reboiler is arranged to receive at least a portion of the cooled third product stream and provide heat energy to the stabilizer column, and wherein at least a portion of the heat energy for the second reboiler is provided from the cooled third product stream such that said second reboiler outputs a fourth product stream, wherein at least a portion of said fourth product stream is fed to the means for cooling, wherein said means for cooling such as first heat exchanger is arranged to provide at least a portion of the further cooled product stream.

[0052] The second reboiler may receive a take-off stream from the stabilizer column and provide a return stream, arranged to be fed to the stabilizer column. The second reboiler may be a side-drawn reboiler arranged to provide heat energy to minimum one equilibrium stage above the lowest equilibrium stage or the second reboiler may be arranged to provide heat energy the lowest equilibrium stage of said stabilizer column, thus providing heat energy to the bottom of the stabilizer column. For side-drawn reboilers, the temperature of the take-off stream is lower than the temperature at the bottom of the first concentration column. Preferably, the second reboiler is arranged to provide heat energy to the bottom of the stabilizer column.

[0053] Independently of such specific arrangement, said second reboiler provides heat energy to a take-off stream to provide a return steam, which is fed to the stabilizer column. Hence, said second reboiler is arranged to provide at least a portion of or alternatively all the energy contribution required to drive the stabilization process of the first raw product stream. The arrangement of the second reboiler may depend on the level of heat energy available in the at least a portion of the cooled third product stream.

[0054] The cooling arrangement may comprise a second heat exchanger. More specifically, the system may further comprises a second heat exchanger, wherein the second heat exchanger is arranged to receive at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream and the second heat exchanger is arranged to provide heat energy to the first raw product stream, wherein at least a portion of the heat energy for the first raw product stream is provided from the cooled third product stream and / or from the at least a portion of a stream derivable from said cooled third product stream. Consequently, the cooled third product stream may be arranged to provide additional heat energy to the process within the stabilizing column.

[0055] It is specifically preferred, for the system to comprise more than one heat integration unit, most preferably wherein the more than one unit is arranged in series. This is an advantage because it allows for the excess heat energy of the cooled third product stream and / or excess heat energy of one or more streams derivable from said cooled third product stream to be provided to streams within the system hereby providing energy consumption optimisation of the system for distillation. In this way, the system may be arranged with the cooling arrangements specifically, comprising a second reboiler and a second heat exchanger, wherein the second reboiler is arranged to receive at least a portion of the cooled third product stream and provide heat energy to the stabilizer column, and wherein at least a portion of the heat energy for the second reboiler is provided from the cooled third product stream such that said second reboiler outputs a fourth product stream, wherein at least a portion of said fourth product stream is fed to the second heat exchanger, wherein the second heat exchanger is arranged to provide heat energy to the first raw product stream, and wherein at least a portion of the heat energy for the first raw product stream is provided from the fourth product stream. Specifically for the system comprising a second reboiler and a second heat exchanger, any one of the second reboiler and / or the second heat exchanger may be arranged to provide at least a portion of the further cooled product stream suitable for being received by the drum.

[0056] The system may be arranged with the cooling arrangements specifically, comprising a second reboiler, second heat exchanger and means for cooling such as the first heat exchanger, wherein the second reboiler is arranged to receive at least a portion of the cooled third product stream and provide heat energy to the stabilizer column, and wherein at least a portion of the heat energy for the second reboiler is provided from the cooled third product stream such that said second reboiler outputs a fourth product stream, wherein at least a portion of said fourth product stream is fed to the second heat exchanger, wherein the second heat exchanger is arranged to provide heat energy to the first raw product stream, and wherein at least a portion of the heat energy for the first raw product stream is provided from the fourth product stream such that said second heat exchanger outputs a fifth product stream, wherein at least a portion of said fifth product stream is fed to a further cooling arrangement such as the first heat exchanger such to provide at least a portion of the further cooled product stream. This arrangement of compressor, first reboiler, and arrangement of the second reboiler, second heat exchanger, and the first heat exchanger allows for optimised exploitation of the heat energy available in the first product stream. Most preferably, the system comprises cooling arrangements consisting of a second reboiler, a second heat exchanger, and first heat exchanger arranged in series. Specifically, the second reboiler is arranged to receive at least a portion, preferably all of the cooled third product stream and provide heat energy to the stabilizer column. Preferably, the cooled third product stream is a liquid at its saturation temperature (e.g. 130 °C) and it is cooled in the second reboiler. At least a portion of the heat energy for the second reboiler is provided from the cooled third product stream such that said second reboiler outputs a fourth product stream. At least a portion, preferably all of said fourth product stream is fed to the second heat exchanger. Typically, the fourth product stream has a temperature of 90-110 °C such as 100°C and a pressure of -0.2 to 9.0 bar g, such as 7.0-8.0 bar g. The second heat exchanger is arranged to provide heat energy to the first raw product stream, such that at least a portion of the heat energy for the first raw product stream is provided from the fourth product stream and said second heat exchanger outputs a fifth product stream. The fifth product stream may have a temperature in the range of 70-80°C. At least a portion, preferably all of said fifth product stream is fed to the first heat exchanger, such that said first heat exchanger is arranged to provide the further cooled product stream. Within said system the second reboiler may preferably be arranged to provide heat energy to the bottom of the stabilizer column.

[0057] The system may further comprise at least one additional temperature regulating unit, such further comprise at least one additional unit suitable for changing the temperature / pressure of a gas or liquid. The at least one additional temperature regulating unit may be arranged on the first raw product stream and / or on the second raw product stream and / or optionally on any portion of a stream derivable from said first raw product stream. Preferably, the at least one additional temperature regulating unit is arranged to increase the temperature of the first raw product stream and / or on the second raw product stream. Hence, the system may further comprise an additional temperature regulating unit arranged to provide additional heat energy to at least a portion of any one of the first raw product stream, the second raw product stream, the cooled third product stream, the fourth product stream, and / or the fifth product stream. Comprising the at least one additional temperature regulating unit in the system for distillation provide an alternative way of tuning the temperature / pressure of the first raw product stream and / or any portion of a stream derivable from said first raw product stream such that the cooling arrangement is arranged to provide a suitable further cooled product stream to be received by the drum. Consequently, comprising the at least one additional temperature regulating unit in the system such as arranged on the first raw product stream may provide for a more flexible system arrangement and remove optional means of cooling in the cooling arrangement. Specifically, the at least one additional temperature regulating unit may be a heat exchanger, an electrical heater or any other suitable unit. Preferably, the at least one additional temperature regulating unit is a heat exchanger wherein the heat exchanger may be arranged to receive at least a portion of the internal first vapor stream from the stabilizer column and further arranged to transfer heat energy from said internal first vapor stream from the stabilizer column to the first raw product stream or any portion of a stream derivable from said first raw product stream. Alternatively, or additionally, the at least one additional temperature regulating unit is a heat exchanger wherein the heat exchanger may be arranged to receive at least a portion of the first condensate stream from first concentration column and further arranged to transfer heat energy from said first condensate stream from first concentration column to the first raw product stream or any portion of a stream derivable from said first raw product stream such as the second raw product stream. Specifically, for the system comprising a second reboiler and a second heat exchanger, wherein any one of the second reboiler and / or the second heat exchanger is arranged to provide at least a portion of the further cooled product stream suitable for being received by the drum, said system may further comprise an additional temperature regulating unit arranged to control the temperature / pressure of the first raw product stream and / or of any portion of a stream derivable from said first raw product stream.

[0058] Drum

[0059] Independently of the specific arrangement within the cooling arrangement, the drum is arranged to receive at least a portion of the further cooled product stream and provide a first distilled product stream. Preferably, at least a first portion of said first distilled product stream is fed as a feed to the first compressor and at least a second portion of said first distilled product stream is provided from said system for distillation. Additionally, at least a third portion of said first distilled product stream may be fed as a reflux feed to the first concentration column.

[0060] Typically, the first distilled product stream is a liquid stream. The system may further comprise at least one pump located on the first distilled product stream and / or on any stream derivable from the first distilled product stream. In this way, the system may further comprise a pump arranged to provide additional pressure to the at least a first portion of said first distilled product stream fed as a feed to the first compressor. Said pump may allow for regulation of the pressure of said first portion of said first distilled product stream, such as for increasing the pressure of the first portion of said first distilled product stream before said first portion of said first distilled product is fed as a feed to the first compressor.

[0061] Consequently, the pump may be arranged to regulate the pressure of the at least first portion of the distilled product stream. Additional or alternatively, at least one pump may be located on the first distilled product stream and / or on any stream derivable from the first distilled product stream to allow for at least a portion such as at least a third portion a of the first distilled product stream to be lifted to the top of the first concentration column as a reflux feed.

[0062] Vapor recompression

[0063] The first compressor is arranged to receive at least a portion of the first product stream and a pure product stream so as to output a second product stream. Specifically, the pure product stream arranged to be received by the first compressor may comprise at least a first portion of said first distilled product stream. Additionally, or alternatively, the pure product stream arranged to be received by the first compressor may comprise a pure product stream from storage such as from a product storage tank. Preferably, at least a first portion of said first distilled product stream is fed as a feed to the first compressor. Hence the first distilled product stream is fed as a feed to the first compressor as at least a portion of the pure product stream. In this way, the first compressor may be arranged to receive at least a portion, such as all of the first product stream and to receive a first portion of the first distilled product stream and to output a second product stream. The advantage of a pure product stream such as a first portion of said first distilled product stream being fed as a feed to the first compressor is that the pure product acts as a cooling liquid such regulates (e.g. reduces) the temperature of the stream within the first compressor (e.g. provide injection for cooling so the temperature is reduced) such to provide a second product stream. Preferably, the second product stream is a compressed and superheated vapor, compressed being relative to the first product stream. An additional benefit of adding the pure product stream to the compressor is that it is much easier to control the temperature of the outlet stream of the compressor, i.e. the temperature adjustment occurs much faster and can be made more precise by injecting and mixing another fluid, preferably a liquid, into the compressor feed compared to an indirect water cooling.

[0064] The first compressor comprises one or more compression stages. The first compressor may comprise two or more compression stages. The first compressor may be arranged to comprise an initial compression stage, and one or more following compression stages. The first compressor may comprise a final compression stage, wherein the final compression stage outputs at least a portion of the second product stream.

[0065] In one or more examples the flow of pure product stream provided to the first compressor corresponds to to 1.5%-3.5%, preferably 2.0%-3.0%, preferably 2.6%-2.8% of the gas flow of the first product stream (measured in kg / h). For a first compressor comprising one or more compression stage the addition of pure product to each compressor stage are within the same ranges, i.e. 1.5%-3.5%, preferably 2.0%-3.0%, preferably 2.6%-2.8% higher flow (kg / h) after the compressor compared to before the compressor.

[0066] It is preferred to cool to just above the saturation temperature, i.e. 2°C-3°C above the saturation temperature. This prevents condensation into the next stage because compressor generally does not like liquids. Additionally, a lower temperature provides a lower volume, and therefore less power required in the subsequent compressor stage. By injecting the pure product stream as fluid cooling, such as liquid cooling, in the compressor stage it is possible to control the temperature accurate within the desired range close to the saturation temperature. An inefficient cooling, or an operation of the first compressor at higher temperatures, results in higher and excessive power consumption.

[0067] The pure product stream arranged to be received by the first compressor such as the first portion of said first distilled product stream may be arranged to be split into sub-streams, wherein such sub-streams may be arranged to be fed as feed(s) upstream or downstream compression stage(s). The term upstream is here used to refer to just prior to a compression stage whereas the term downstream is used to refer to just after a compression stage. This allows for a sub-portion of the pure product stream such as a sub-portion of the first portion of said first distilled product stream to be arranged to be fed as feed(s) just prior to any compression stage or just after any compression stage within the first compressor hereby providing injection cooling. Typically, the number of sub-streams within said compressor is equal to the number of compression stages comprised within the first compressor or the number of sub-streams within said first compressor is ±1 of the number of compression stages comprised within the first compressor. In this way, the pure product stream such as one or more sub-streams thereof may be arranged to be provided to the first compressor between any two compression stages, optionally also before the initial compression stage and / or after the final compression stage. Consequently, there may be injection cooling between any two stages and possibly also before the first and after the final compression stage. Since the flow of injection cooling is within 1.5% to 3.5% (kg / h) of the upstream flow it has been found that the pure product stream can be added as a liquid since it simply would be evaporated going through the compressor stage and keeping the temperature down. A compressor is able to cope with such small amounts of liquid.

[0068] Specifically, wherein the first compressor comprises one compression stage, at least one substream of the pure product stream such as of the first portion of said first distilled product stream may be arranged to be fed as a feed upstream and / or downstream of the compression stage. Specifically, wherein the first compressor comprises two or more compression stages, one or more sub-stream(s) of the pure product stream such as of the first portion of said first distilled product stream may be arranged to be provided to the first compressor between any two compression stages, optionally also before the initial compression stage and after the final compression stage.

[0069] Independent on the specific arrangement of sub-steams within said first compressor, each of the sub-streams may be turned on, off or be throttled individually as required. Herein turned on is used to refer to the sub-stream being partly or fully open such as l%-100% open, off is used to refer to the sub-stream being fully closed such being 0% open and throttled is used to refer to the sub-stream being less than fully open such as 1-99% open. This is advantageous because the operation of each compression stage can be precisely controlled and the full potential of the first compressor can be exploited.

[0070] Independently of the specific arrangement within the first compressor, the system wherein the first compressor is arranged to receive at least a portion of the first product stream and a pure product stream so as to output a second product stream such as wherein at least a first portion of said first distilled product stream is fed as a feed to the first compressor provide the advantage of allowing for the distillation system to be self-sustaining with respect to providing the energy necessary to drive the distillation process. This is because the mass flow out of the first compressor (i.e. the second product stream) has a larger mass flow due to the addition of the pure product stream and therefore it is possible to heat transfer more heat from the second product stream in a downstream heat exchanger, such as the first reboiler. Depending on the flow of pure product stream and the temperature of the streams it may be possible increase the heat exchanged in the downstream heat exchanger by 8-12 %. With this it follows that the system may require no further steam reboiler(s), electrical reboiler(s) and / or steam condensate exchangers. Instead, the energy necessary to drive the distillation process, may be provided via the arrangement of the first compressor. Driving the first compressor does come with an energy requirement, however such requirement may be provided by renewable energy resources. Additionally, the electrical power consumption of said first compressor is lower than what can be achieved from alternative electrical energy sources e.g. electrical reboiler(s).

[0071] Even though the system may be self-sustaining, the systems may benefit from comprising arrangements which allows for a flexible energy supply. In this way, the system may further comprises one or more steam reboiler(s), one or more electrical reboiler(s) and / or steam condensate exchangers, wherein said reboiler(s) and / or exchangers are arranged to provide supplemental heat energy to at least one of i) the first raw product stream via heat exchanger(s), ii) the stabilizer section such as to the stabilizer column via reboiler(s), iii) the first concentration column via reboiler(s), and / or iv) the second raw product stream via heat exchanger(s). This arrangement opens for the possibility of supplying heat energy from stream streams generated elsewhere such as within a chemical plant.

[0072] The system may further be arranged to comprise arrangements allowing for at least a portion of the first product stream to bypass the first compressor and the first reboiler. Specifically, the system may be arranged to further comprise that the cooling arrangement is arranged to receive at least a second portion of the first product stream. As the cooling arrangement may comprise one or more heat integration unit(s) and / or means for cooling, the at least second portion of the first product stream may be arranged to be fed as a feed upstream any one of the one or more heat integration unit(s) and / or upstream any one of the means for cooling. Preferably, the at least second portion of the first product stream is arranged to be fed into a means for cooling. Alternatively or additionally, the at least second portion of the first product stream is arranged to be admixed with any stream within the cooling arrangement such as optionally be admixed with at least a portion of the fourth product stream from the second reboiler or fifth product stream from the second heat exchanger. Alternatively or additionally, the system may be arranged to further comprise a second means for cooling such as a heat exchanger, said second means for cooling may be further arranged to provide a second further cooled product stream, wherein the drum may be arranged to receive said second further cooled product stream. Consequently, a second portion of the first product stream from the first concentration column may be arranged to be received by the cooling arrangement such as by the first heat exchanger and / or may be arranged to be received by a second means for cooling such as a heat exchanger, optionally, wherein when the second means for cooling is arranged to receive at least a portion of the second portion of the first product stream, said second means for cooling is arranged to provide a second further cooled product stream and the drum is arranged to receive at least a portion of the second further cooled product stream.

[0073] Having the cooling arrangement arranged to receive at least a second portion of the first product stream and / or having the system arranged with a second cooling means providing second further cooled product stream to the drum allows for the first product stream to bypass the first compressor and the first reboiler. This may be advantageous at times where renewable energy is not available, and / or where other heat sources are available in excess. It may be further beneficial for the system to be arranged such that the system further comprises a third reboiler arranged to provide heat energy to the first concentration column, wherein the third reboiler is arranged to receive heat energy from a steam stream or other heat sources. Herein other heat sources may be electric heaters, or a transfer of heat energy from a product stream (e.g. comprising excess heat otherwise wasted) whereas steam stream may refer to a low-pressure steam stream, both of which may be available within said system for distillation or within a chemical plant. Specifically, the third reboiler may be arranged to receive a steam stream such that at least a portion of the heat energy for the third reboiler is provided from the steam stream. The third reboiler may further be arranged to output a steam condensate stream. Preferably, the third reboiler is arranged to provide heat energy to the bottom of the first concentration column. Having a system further comprising a third reboiler allows for the system to operate partly on steam energy and partly on the energy provided by the first compressor. Additionally, this arrangement allows for the distillation within the first column to operate only on steam during some periods such as during times a chemical plant provides steam in excess and further it allows for the distillation to operate only on heat energy provided by the first compressor when such arrangement provide better energy optimization.

[0074] Additionally, the system may further comprise a fourth reboiler arranged to provide heat energy to the stabilizer column, wherein the fourth reboiler is arranged to receive heat energy from steam or other heat sources. Other heat sources may be electric heaters, or a transfer of heat energy from a product stream (e.g. comprising excess heat otherwise wasted) whereas steam stream may refer to a low pressure steam stream or steam condensate stream, both of which may be available within said system for distillation or within a chemical plant. Specifically, the fourth reboiler may be arranged to receive a steam stream such that at least a portion of the heat energy for the fourth reboiler is provided from the steam stream. The fourth reboiler may further be arranged to output a steam condensate stream. Preferably, the fourth reboiler is arranged to provide heat energy to the bottom of the stabilizer column. Having such fourth reboiler means that the stabilization may operate partly on steam energy and partly on the energy provided by the first compressor.

[0075] Additionally, this arrangement allows for the stabilization to operate only on steam during some periods such as during times a chemical plant provides steam in excess, and it allows for the stabilization to operate only on heat energy provided by the first compressor when such arrangement provide better energy optimization.

[0076] In one or more examples the first compressor comprises means for measuring a temperature upstream and / or downstream of the first compressor, such as upstream and / or downstream of the one or more compression stages, such as the temperature of the first product stream and / or the second product steam.

[0077] In one or more examples the first compressor comprises means for measuring a flow upstream and / or downstream of the one or more compression stages such as measuring the flow of the first product stream and / or the second product stream.

[0078] In one or more examples the first compressor comprises a valve coupled to the pure product stream. The valve is configured to adjust the flow of the pure product stream, i.e. the cooling of the first compressor. The first compressor may comprise means for measuring the flow of the pure product stream.

[0079] In one or more examples the first compressor comprises a controller in communication with the means for measuring a temperature and / or means for measuring the flow of the second product stream and configured to adjust the valve based on the measured temperature(s) and flow(s).

[0080] The means for measuring a temperature, the means for measuring a flow, the valve, and / or the controller may be provided together with first compressor according to any of the aspects of the invention, i.e. in a system, in a method, or in a revamp of an existing system.

[0081] Second concentration column

[0082] The system may further comprise a second concentration column, a second drum, a second pump, and a fifth reboiler and wherein said second concentration column is arranged to receive at least a portion of the first condensate stream from the first concentration column and provide an sixth product stream, a second condensate stream, and a third off-stream, and wherein said fifth reboiler is arranged to provide heat energy to the second concentration column. Preferably, the third reboiler is arranged to receive at least a portion of the sixth product stream to output a seventh product stream, wherein said second drum is arranged to receive at least a portion of said seventh product stream and output a eights product stream. The second pump may be arranged to receive at least a portion of the eights product stream and provide a ninth product stream, wherein a first portion of said ninth product stream is arranged to be fed as a feed to the second concentration column, and optionally, wherein a second portion of said ninth product stream is arranged to be combined with at least a portion of the first distilled product stream such as with a second portion of the first distilled product stream provided from the system for distillation.

[0083] More specifically, the second concentration column may be arranged to receive at least a portion of the first condensate stream from the first concentration column and provide an sixth product stream, the third reboiler may be arranged to receive at least a portion of the sixth product stream to output a seventh product stream, and the third reboiler may further be arranged to transfer heat energy from at least a portion of the sixth product stream to the first concentration column.

[0084] The system for distillation may comprise additional concentration columns, such as two or more concentration columns. The second concentration column may be a medium pressure distillation column. Typically, the operation pressure of the second concentration column is between 2.5-10.0 bar g such as preferably between 2.5-7.0 bar g, such as preferably 2.5-6.0 bar g. Typically, the operation pressure of the second concentration column is above the operation pressure of the first concentration column.

[0085] The sixth product stream comprises vaporised product, such as 97 vol% product, or preferably 99 vol% product. This sixth product stream may preferably be 99 vol% methanol. The third off-stream may comprise methanol, water and higher alcohols. Typically, the third off-stream is a liquid stream.

[0086] The second condensate stream may be a second distillation water stream, or it may be a stream comprising at least a portion of the product. Preferably, wherein the system for distillation comprises only the first and the second concentration column, the second condensate stream is a first distillation water stream, wherein the distillation water stream comprises 99 weight% water.

[0087] The fifth reboiler is arranged to provide at least a portion of the necessary energy for driving the distillation within the second concentration column. Specifically, the fifth reboiler is arranged to provide heat energy to the bottom of the second concentration column, preferably wherein the fifth reboiler is arranged to receive a take-off stream and provide a return stream, wherein at least a portion of the return stream is arranged to be fed to the second concentration column.

[0088] Having a system comprising a third reboiler and second concentration column, wherein said second concentration column is arranged to receive at least a portion of the first condensate stream from the first concentration column and provide an sixth product stream, wherein the third reboiler is arranged to receive at least a portion of the sixth product stream to output a seventh product stream, wherein the third reboiler is a arranged to transfer heat energy from at least a portion of the sixth product stream to the first concentration column, provide a system allowing for optimised distillation of the first raw product stream such as of a first raw methanol stream.

[0089] Chemical plant

[0090] In a second aspect, the present invention relates to a chemical plant comprising : a syngas stream; a product synthesis section; the system for distillation according to the system disclosed herein, wherein said product synthesis section is arranged to receive at least a portion of said syngas stream and output a first raw product stream, and wherein said system for distillation is arranged to receive said first raw product stream from said product synthesis section and provide a first distilled product stream such as a second portion of said first distilled product stream.

[0091] The chemical plant may further comprise that the syngas stream comprises hydrogen, wherein the syngas stream is provided from natural gas such as from steam reforming of natural gas or from gasification of coal.

[0092] In the chemical plant, the syngas stream may comprise hydrogen, wherein at least a portion of the hydrogen is provided from electrolysis of H2O. The syngas stream may further comprise carbon monoxide and carbon dioxide. The carbon dioxide may be provided from any source such as from natural gas such as from steam reforming of natural gas or from gasification of coal, preferably at least a portion of the carbon dioxide is provided from a carbon dioxide removal unit arranged to capture carbon dioxide. The carbon monoxide may be provided from any source such as from natural gas such as from steam reforming of natural gas or from gasification of coal. Specifically, at least a portion of the carbon monoxide may be provided from electrolysis of CO2.

[0093] Specifically, the chemical plant may further comprise an e-syngas section. The e-syngas section may be arranged to receive a H2O-rich feed and a CO2-rich feed. The chemical plant, more specifically the e-syngas section, may further comprise at least one electrolysis section such as a first solid oxide electrolysis section for electrolysis. Preferably, the first solid oxide electrolysis section may be suitable for H2O electrolysis such to provide the H2-rich feed. Additionally, or alternatively, the first solid oxide electrolysis section may be suitable for CO2electrolysis such to provide the CO-rich feed.

[0094] The chemical plant may be a methanol plant, said methanol plant comprising a methanol synthesis section, said methanol synthesis section being arranged to receive a syngas stream and output the first raw product stream, being a raw methanol stream. Preferably, said chemical plant is a methanol plant.

[0095] The e-syngas section optionally comprised in the chemical plant and / or the product synthesis section comprised in the chemical plant may be arranged to provide additional heat energy to at least one of i) the first raw product stream, ii) the stabilizer column, iii) and / or the first concentration column. Specifically, the e-syngas section and / or the product synthesis section may be arranged to provide excess steam stream(s) to the third or fifth reboiler such provide heat energy to the first or second concentration column. Additionally, the e-syngas section and / or the product synthesis section may be arranged to provide excess steam stream(s) to the fourth reboiler such provide heat energy to the stabilizer column. In this way, in addition to the system for distillation being a self-sustaining distillation system, additional arrangements may allow for excess heat energy to be provided to the distillation system. Such arrangement(s) specifically provides the advantage of flexible heat supply, as steam produced within said chemical plant during operation such as from the product synthesis section may be used for distillation herby reducing the overall energy consumption of the chemical plant as driving the first compressor does come with an energy requirement. When using the stream produced within said chemical plant, the system for distillation may be arranged such to bypass the first compress.

[0096] Method for distillation

[0097] In a third aspect, the present invention relates to a method for distillation of a first raw product stream in a system according to the system disclosed herein is provided, wherein said method comprises: feeding a first raw product stream to the stabilizer section and providing a second raw product stream, and a first off-gas stream; feeding at least a portion of the second raw product stream to the first concentration column, distilling said stream and providing a first vaporised product steam from said first concentration column, a first condensate stream, and optionally a second off- stream; feeding at least a portion of the first product stream and a pure product stream to the first compressor, and providing a second product stream from said first compressor; feeding at least a portion of the second product stream to the first reboiler, and hereby providing heat energy to the first concentration column, wherein the step of providing heat energy to the first concentration column comprises providing heat energy from at least a portion of the second product stream to the first reboiler and providing a cooled third product stream from said first reboiler; feeding at least a portion of the third product stream to the cooling arrangement to provide the further cooled product stream; feeding at least a portion of the further cooled product stream to the drum to provide a first distilled product stream.

[0098] Specifically, said method may further comprise feeding at least a first portion of said first distilled product stream as a feed to the first compressor and / or feeding a pure product stream from storage such as from a product storage tank as a feed to the first compressor. Preferably, the method comprises feeding at least a first portion of said first distilled product stream as a feed to the first compressor as at least a portion of the pure product stream. The method may further comprise compressing the first portion of said first distilled product stream and / or pure product stream from storage such as from a product storage tank before said stream(s) is / are fed as a feed to the first compressor.

[0099] Additionally, wherein the system comprises a second reboiler, wherein the system comprises a second reboiler, said method comprising feeding at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream from said first reboiler to the second reboiler and hereby providing heat energy to the stabilizer column, wherein the step of providing heat energy to the stabilizer column comprises providing heat energy from the at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream to the second reboiler.

[0100] The method may further comprise, wherein said system further comprises a second heat exchanger, said method may further comprise feeding at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream to the second heat exchanger and hereby providing heat energy to the first raw product stream, wherein the step of providing heat energy to the first raw product stream comprises providing heat energy from at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream to the second heat exchanger.

[0101] The method may further comprise, wherein the system further comprises a first heat exchanger, said method may further comprise feeding at at least a portion of the cooled third product stream and / or one or more streams derivable from said cooled third product stream to the first heat exchanger so as to provide at least a portion of the further cooled product stream.

[0102] Specifically, wherein said system further comprises a second reboiler, a second heat exchanger and a first heat exchanger, the method may comprise feeding at least a portion of the cooled third product stream from said first reboiler to the second reboiler and hereby providing heat energy to the stabilizer column, wherein the step of providing heat energy to the stabilizer column comprises providing heat energy from the at least a portion of the cooled third product stream to the second reboiler hereby providing a fourth product stream. feeding at least a portion of the fourth product stream to the second heat exchanger and hereby providing heat energy to the first raw product stream, wherein the step of providing heat energy to the first raw product stream comprises providing heat energy from at least a portion of the fourth product stream to the second heat exchanger hereby providing a fifth product stream; feeding at at least a portion of the fifth product stream to the first heat exchanger and provide at least a portion of the further cooled product stream.

[0103] The method may further comprise, wherein the first compressor comprises one compression stage, said method further comprises feeding at least a sub-portion of the pure product stream such as of the first portion of said first distilled product stream as a feed upstream and / or downstream of the compression stage.

[0104] The method may further comprise, wherein the first compressor comprises two or more compression stages, said method further comprises feeding one or more sub-stream(s) of the pure product stream such as of the first portion of said first distilled product stream to the first compressor between any two compression stages, optionally also before the initial compression stage and / or after the final compression stage.

[0105] Specifically, the method may further comprise operating the first concentration column at a pressure of between 0.1-10.0 bar g, preferably 0.1-2.5 bar g, preferably 0.1-1.5 bar g. The operation pressure interval here provided relates to the preferred pressure within the column.

[0106] Specific embodiments

[0107] Figure 1 shows a first schematic drawing of the system (200) for distillation. The system (200) comprises: a first raw product stream (1); a stabilizer section (10) comprising a stabilizer column (10a); a first concentration column (20); a first compressor (30); a first reboiler (40); a cooling arrangement (50); and a drum (70). The stabilizer section (10) is arranged to receive the first raw product stream (1) and provide a second raw product stream (11), and a first off-gas stream (12). The first concentration column (20) is arranged to receive the second raw product stream (11) and distil said stream (11) so as to output a first product stream (21), a first condensate stream (29), and optionally a second off-stream (22). The first compressor (30) is arranged to receive at least a portion of the first product stream (21) and a pure product stream (72a, 73) so as to output a second product stream (31). The first reboiler (40) is arranged to receive at least a portion of the second product stream (31) and provide heat energy to the first concentration column (20), wherein at least a portion of the heat energy for the first reboiler (40) is provided from the second product stream (31) such that said first reboiler (40) outputs a cooled third product stream (41). The cooling arrangement (50) is arranged to receive at least a portion of the cooled third product stream (41) and provide a further cooled product stream (60). The drum (70) is arranged to receive at least a portion of the further cooled product stream (60) and provide a first distilled product stream (71).

[0108] Optionally, at least a first portion (72a) of said first distilled product stream (71) is fed as a feed to the first compressor (30) and at least a second portion (72b) of said first distilled product stream (71) is provided from said system (200) for distillation. Suitably, at least a third portion (72c) of said first distilled product stream (71) may be fed as a reflux feed to the first concentration column (20).

[0109] Specifically, the first reboiler (40) is arranged to provide heat energy to the bottom of the first concentration column (20), wherein said first reboiler (40) receives a first take-off stream (23) from the first concentration column (20) and provides a first return stream (24), arranged to be fed to the first concentration column (20). The first take-off stream (23) is typically a liquid from the column that is at least partly evaporated into the first return stream (24) by heat exchange with the second product stream (31).

[0110] Specifically, the second product stream (31) may be a compressed and superheated vapor that is cooled to saturation point (e.g. 130°C) and condensed at that temperature in the first reboiler (40). The temperature of the superheated vapor could be as low as a few degrees above saturation point depending on how much cooling liquid (72a) is injected.

[0111] Additionally, Figure 1 shows the method steps for distillation in the system as disclosed herein. Specifically the method for distillation of a first raw product stream (1) comprises: feeding a first raw product stream (1) to the stabilizer section (10) and providing a second raw product stream (11), and a first off-gas stream (12), feeding at least a portion of the second raw product stream (11) to the first concentration column (20), distilling said stream (11) and providing a first vaporised product steam (21) from said first concentration column (20), a first condensate stream (29), and optionally a second off-stream (22). The method further comprises feeding at least a portion of the first product stream (21) and a pure product stream (72a, 73) to the first compressor (30), and providing a second product stream (31) from said first compressor (30); feeding at least a portion of the second product stream (31) to the first reboiler (40), and hereby providing heat energy to the first concentration column (20), wherein the step of providing heat energy to the first concentration column (20) comprises providing heat energy from at least a portion of the second product stream (31) to the first reboiler (40) and providing a cooled third product stream (41) from said first reboiler (40). The method further comprises feeding at least a portion of the third product stream (41) to the cooling arrangement (50) to provide the further cooled product stream (60), feeding at least a portion of the further cooled product stream (60) to the drum (70) to provide a first distilled product stream (71). Optionally, the method may further comprise feeding at least a first portion (72a) of said first distilled product stream (71) as a feed to the first compressor (30).

[0112] For the method of distillation, where the first raw product stream comprises methanol, the first product stream (21) is suitably approx. 68 °C, the second product stream (31) has a saturation temperature of in the interval 100-140 °C, such as 130°C. Preferably, the second product stream (31) is a compressed and superheated vapor that is cooled to saturation point (e.g. 130°C) and condensed at that temperature in the first reboiler (40). The temperature of the superheated vapor could be as low as a few degrees above saturation point depending on how much cooling liquid (72a) is injected.

[0113] Figure 2 shows a second schematic drawing of the system for distillation comprising the layout as comprised in Figure 1 and further comprising a pump (75) located on first distilled product stream (71). This allows for the at least a first portion (72a) of said first distilled product stream (71) having a suitable pressure when entering the first compressor (30), such to allow for the at least a first portion (72a) of said first distilled product stream (71) to function as a cooling liquid for the first product stream. Suitably, the pump may be located on the first distilled product stream. Typically, the drum is located on the ground, hence a pump located on the first distilled product stream may provide the pressure to lift the at least a first portion (72a) and the at least second portion (72b) of said first distilled product stream (71) to the top of the first concentration column. Alternatively or additionally, the system may comprise one or more pumps, wherein a first pump may be located on the first portion (72a) of said first distilled product stream (71) and / or a second pump may be located on the second portion (72c) of said first distilled product stream. Such arrangements would allow for alternative ways to provide the pressure to lift the at least a first portion (72a) and the at least second portion (72b) of said first distilled product stream (71) (liquid) to the top of the first concentration column.

[0114] For the method of distillation, where the first raw product stream comprises methanol, the first distilled product stream (71) has suitably a pressure of 0 bar g at the inlet of the pump (75). Typically, the pressure of the at least first portion (72a) of said first distilled product stream (71) at the inlet of the first compressor (30) is in the range of 0-20 bar g. Typically, the pressure of the at least a third portion (72c) of said first distilled product stream (71) optionally fed as a reflux feed to the first concentration column (20) is in the range of 0-20 bar g when refluxed to the first concentration column (20).

[0115] Figure 3 shows a third schematic drawing of the system for distillation comprising the layout as comprised in Figure 1 and 2, however with the specification that the cooling arrangement (50) comprises a first heat exchanger (58) wherein said first heat exchanger (58) is arranged to provide at least a portion of the further cooled product stream (60). The cooling arrangement (50) may be arranged to comprise one or more cooling unit(s). In this way, the first heat exchanger (58) may be arranged to receive at least a portion of the cooled third product stream (41) and provide a further cooled product stream (60) or one or more cooling unit(s) may be arranged to receive at least a portion of the cooled third product stream (41) so as to provide a stream to the first heat exchanger (58) such that said first heat exchanger (58) is arranged to provide at least a portion of the further cooled product stream (60).

[0116] Figure 4 shows a fourth schematic drawing of the system for distillation comprising the layout as comprised in Figure 1, 2 and 3, however with the specification that the cooling arrangement (50) further comprises a second reboiler (51), wherein the second reboiler (51) is arranged to receive at least a portion of the cooled third product stream (41) and provide heat energy to the stabilizer column (10a), and wherein at least a portion of the heat energy for the second reboiler (51) is provided from the cooled third product stream (41) such that said second reboiler (51) outputs a fourth product stream (53), wherein at least a portion of said fourth product stream (53) is fed to a different one of said cooling arrangements (55, 58) such to provide the further cooled product stream (60).

[0117] Specifically, the second reboiler (51) is arranged to provide heat energy to the bottom of the stabilizer column (10a), wherein said second reboiler (51) receives a second take-off stream (13) from the stabilizer column (10a) and provides a second return stream (52), arranged to be fed to the stabilizer column (10a).

[0118] Figure 5 shows a fifth schematic drawing of the system for distillation comprising the layout as comprised in Figure 1-4, however with the difference that the said cooling arrangements further comprises a second heat exchanger (55) wherein the second heat exchanger (55) is arranged to receive at least a portion of said fourth product stream (53) and provide heat energy to the first raw product stream (1), and wherein at least a portion of the heat energy for the first raw product stream (1) is provided from the fourth product stream (54) such that said second heat exchanger (55) outputs a fifth product stream (56), wherein at least a portion of said fifth product stream (56) is fed to the first heat exchanger (58) such to provide at least a portion of the further cooled product stream (60).

[0119] Figure 6 shows a sixth schematic drawing of the system for distillation comprising the layout as comprised in Figure 1-2, however here specifically where the cooling arrangements consist of a second reboiler (51) and a second heat exchanger (55), wherein the second reboiler (51) is arranged to receive at least a portion of the cooled third product stream (41) and provide heat energy to the stabilizer column (10a), and wherein at least a portion of the heat energy for the second reboiler (51) is provided from the cooled third product stream (41) such that said second reboiler (51) outputs a fourth product stream (53), wherein the second heat exchanger (55) is arranged to receive at least a portion of said fourth product stream (53) and provide heat energy to the first raw product stream (1), and wherein at least a portion of the heat energy for the first raw product stream (1) is provided from the fourth product stream (53) and wherein said second heat exchanger (55) outputs at least a portion of the further cooled product stream (60).

[0120] Figure 7 shows a seventh schematic drawing of the system for distillation comprising the layout as comprised in any one of Figure 1-6, however with the further specification that at least a second portion (21b) of the first product stream (21) from said first concentration column (20) is arranged to be feed as a fed to a heat exchanger such as to the first heat exchanger (58) and / or to a third heat exchanger (27). When a third heat exchanger is arranged to receive at least a portion of the at least a second portion (21b) of the first product stream (21), the third heat exchanger is further arranged to provide a second further cooled product stream (28) to the drum (70). In this way, the system is arranged with the possibility to bypass at least the heat integration units (51, 55) of the cooling arrangement (50).

[0121] Figure 8 shows a first schematic drawing of a first compressor. The first compressor (30) comprises 3 compression stages (30a, 30b, 30c) and the first portion (72a) of said first distilled product stream (71) is arranged to be split into 4 sub-streams (72ai, 72aii, 72aiii, 72aiv). The first sub-stream (72ai) of the least first portion (72a) of said first distilled product stream (71) is arranged to be fed as a feed upstream the initial stage (30a) of the first compressor (30), and the second sub-stream (72aii) of the least first portion (72a) of said first distilled product stream (71) is arranged to be fed as a feed upstream the second stage (30b) of the first compressor (30). Optionally, the third sub-stream (72aiii) of the least first portion (72a) of said first distilled product stream (71) is arranged to be fed as a feed upstream the third stage (30c). Optionally, the fourth sub-stream of the third sub-stream (72aiii) of the least first portion (72a) of said first distilled product stream (71) is arranged to be fed as a feed downstream the third stage (30c). Any one of the sub-streams (72ai, 72aii, 72aiii, 72aiv) may be turned on, off or be throttled individually as required.

[0122] Figure 9 shows a first schematic drawing of the chemical plant (300). Specifically, the chemical plant comprises: a H2O rich-feed (301); a CO2-rich feed (302); an e-syngas section (310); a product synthesis section (320) and the system for distillation (200). The e-syngas section (310) is arranged to receive said H2O rich-feed (301) and said CO2-rich feed (302), and output a syngas stream (311). The product synthesis section (320) is arranged to receive at least a portion of said syngas stream (311) and output a first raw product stream (1). The product synthesis section (320) may be a methanol synthesis section (320a). The system for distillation (200) is arranged to receive said first raw product stream (1) from said product synthesis section (320) and provide a first distilled product stream (71) such as a second portion (72b) of said first distilled product stream (71).

[0123] EXAMPLE 1

[0124] The following example is calculated on the basis of the production of 300 metric tonnes methanol per day. The methanol plant comprises a stabilizer column and a first concentration column, hence the term "Base" here refers to such system which is used as reference system. The system Base+first compressor then refers to the reference system with the addition of arranging a first compressor as described herein. The system Base+first compressor and bypass of first compressor refers to the system where in addition to the arrangement of the first compressor the distillation system is arranged with a bypass arrangement allowing the reboilers associated with the stabilizer column and first concentration column to receive the steam from the methanol synthesis section.

[0125] The experiment shows that the distillation system comprising the first compressor can be used to provide all the heat energy needed to drive the distillation system. Additionally, the experiment shows a decrease in the amount of power needed to drive the first compressor, if the distillation system further comprises a bypass of the first compressor such that the distillation system is arranged to receive excess steam streams available from the product synthesis section i.e. receive available excess heat energy from the product synthesis section. Therefore, the system has the potential for requiring zero steam as heat source - such that all heat comes from the first compressor and further to combine this with bypass of first compressor such to not waste steam that is produced in the methanol synthesis section and hereby saving compressor power. The power for the first compressor can suitably come from production of renewable electrical power production. In case 1 we do not have liquid injection, but instead cooling of the compressor by air / water. The compressor is cooled to about 2-3°C above the saturation temperature. In this case the flow out of the compressor would be 43217 kg / h (equal to inlet flow) and would be able to transfer 12.0 MW of heat in the downstream heat exchanger I reboiler. In this case it is required to input heat, e.g. as steam, for the remaining 1.4 MW to make grade AA methanol.

[0126] In case 2 the flow after liquid injection is 48417 kg / h. This means that it is possible to transfer 13.4 MW of heat in the downstream heat exchanger I reboiler, which is sufficient to make product with purity for Grade AA methanol. EXAMPLE 2

[0127] The following example is calculated based on Case 2. The first compressor comprises 5 compression stages. Details about each compression stage can be seen in the table below.

[0128] In the example the pure product stream is added by liquid injection after each compression stage. The total power gained in each compression stage summarizes to the 3.161 MW mentioned in EXAMPLE 1.

[0129]

Claims

33CLAIMS1. A system (200) for distillation, said system (200) comprising : a first raw product stream (1); a stabilizer section (10) comprising a stabilizer column (10a); a first concentration column (20); a first compressor (30); a first reboiler (40); a cooling arrangement (50); a drum (70); wherein the stabilizer section (10) is arranged to receive the first raw product stream (1) and provide a second raw product stream (11), and a first off-gas stream (12); wherein the first concentration column (20) is arranged to receive the second raw product stream (11) and distil said stream (11) so as to output a first product stream (21), a first condensate stream (29), and optionally a second off-stream (22); wherein the first compressor (30) is arranged to receive at least a portion of the first product stream (21) and a pure product stream (72a, 73) so as to output a second product stream (31); wherein the first reboiler (40) is arranged to receive at least a portion of the second product stream (31) and provide heat energy to the first concentration column (20), and wherein at least a portion of the heat energy for the first reboiler (40) is provided from the second product stream (31) such that said first reboiler (40) outputs a cooled third product stream (41); wherein the cooling arrangement (50) is arranged to receive at least a portion of the cooled third product stream (41) and provide a further cooled product stream (60); wherein the drum (70) is arranged to receive at least a portion of the further cooled product stream (60) and provide a first distilled product stream (71).

342. The system according to claim 1, wherein the pure product stream (72a, 73) arranged to be received by the first compressor (30) comprises at least a first portion (72a) of the first distilled product stream (71) provided from the drum (70).

3. The system according to any one of the preceding claims, wherein the pure product stream (72a, 73) arranged to be received by the first compressor (30) comprises a pure product stream from storage (73) such as from a product storage tank.

4. The system according to any one of the preceding claims, wherein the second product stream (31) is a compressed and superheated vapor that is cooled to saturation point and condensed at that temperature in the first reboiler (40).

5. The system according to any one of the preceding claims, wherein the cooling arrangement (50) comprises means for cooling (58) arranged to provide at least a portion of the further cooled product stream suitable for being received by the drum.

6. The system according to any one of the preceding claims, wherein the cooling arrangement (50) comprises one or more heat integration units (51,55), said heat integration units being arranged to transfer heat energy from the cooled third product stream and / or from streams derivable from said cooled third product stream to one or more product streams or take-off streams within the system for distillation.

7. The system according to any one of the preceding claims, wherein the cooling arrangement (50) comprises one or more reboilers (51) and / or one or more heat exchangers (55, 58), preferably arranged in series.

8. The system according to any one of the preceding claims, wherein the system further comprises a first heat exchanger (58) wherein said first heat exchanger (58) is arranged to receive at least a portion of the cooled third product stream (41) or at least a portion of one or more stream(s) derivable from the cooled third product stream and provide at least a portion of the further cooled product stream (60).

9. The system according to any one of the preceding claims, wherein the system further comprise a second reboiler (51), wherein the second reboiler (51) is arranged to receive at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream and said second reboiler (51) is arranged to provide heat energy to the stabilizer column (10a), wherein at least a portion of the heat energy for the second reboiler (51) is provided from the cooled third product stream (41) and / or from the at least a portion of a stream derivable from said cooled third product stream.

10. The system according to any one of the preceding claims, wherein the system further comprises a second heat exchanger (55), wherein the second heat exchanger (55) is arranged to receive at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream and the second heat exchanger (55) is arranged to provide heat energy to the first raw product stream (1), wherein at least a portion of the heat energy for the first raw product stream (1) is provided from the cooled third product stream (41) and / or from the at least a portion of a stream derivable from said cooled third product stream.

11. The system according to any one of the preceding claims, wherein any one of the second reboiler (51) or the second heat exchanger (55) is arranged to provide at least a portion of the further cooled product stream suitable for being received by the drum.

12. The system according to claim 11, wherein the system further comprises an additional temperature regulating unit arranged to provide additional heat energy to at least a portion of any one of the first raw product stream (1), the second raw product stream (11), the cooled third product stream (41), the fourth product stream (53), and / or the fifth product stream (56).

13. The system according to any one of claim 1 to 12, wherein the cooling arrangements comprises a second reboiler (51) and means for cooling such as first heat exchanger (58), wherein the second reboiler (51) is arranged to receive at least a portion of the cooled third product stream (41) and provide heat energy to the stabilizer column (10a), and wherein at least a portion of the heat energy for the second reboiler (51) is provided from the cooled third product stream (41) such that said second reboiler (51) outputs a fourth product stream (53), wherein at least a portion of said fourth product stream (53) is fed to the means for cooling, wherein said means for cooling such as first heat exchanger (58) is arranged to provide at least a portion of the further cooled product stream (60).

14. The system according to any one of claim 1 to 12, wherein the cooling arrangements comprises a second reboiler (51), second heat exchanger (55) and means for cooling such as the first heat exchanger (58), wherein the second reboiler (51) is arranged to receive at least a portion of the cooled third product stream (41) and provide heat energy to the stabilizer column (10a), and wherein at least a portion of the heat energy for the second reboiler (51) is provided from the cooled third product stream (41) such that said second reboiler (51) outputs a fourth product stream (53), wherein at least a portion of said fourth product stream (53) is fed to the second heat exchanger (55), wherein the second heat exchanger (55) is arranged to provide heat energy to the first raw product stream (1), and wherein atleast a portion of the heat energy for the first raw product stream (1) is provided from the fourth product stream (53) such that said second heat exchanger (55) outputs a fifth product stream (56), wherein at least a portion of said fifth product stream (56) is fed to a further cooling arrangement such as the first heat exchanger (58) such to provide at least a portion of the further cooled product stream (60).

15. The system according to any one of the preceding claims, wherein at least a second portion (72b) of said first distilled product stream (71) is provided from said system (200) for distillation and / or wherein at least a third portion (72c) of said first distilled product stream (71) is fed as a reflux feed to the first concentration column (20).

16. The system according to any one of the preceding claims, wherein the first compressor (30) comprises one compression stage, and at least one sub-stream of the pure product stream such as of the first portion (72a) of said first distilled product stream (71) is arranged to be fed as a feed upstream and / or downstream of the compression stage.

17. The system according to any one of claims 1-15, wherein the first compressor comprises two or more compression stages and one or more sub-stream(s) of the pure product stream such as of the first portion of said first distilled product stream is arranged to be provided to the first compressor between any two compression stages, optionally also before the initial compression stage and / or after the final compression stage.

18. The system according to any one of the preceding claims, wherein a second portion (21b) of the first product stream (21) from the first concentration column (20) is arranged to be received by the cooling arrangement (50) such as by the first heat exchanger (58) and / or is arranged to be received by a second means for cooling (27) such as a heat exchanger, optionally, wherein when the second means for cooling (27) is arranged to receive at least a portion of the second portion (21b) of the first product stream (21), said second means for cooling (27) is arranged to provide a second further cooled product stream (28) and the drum (70) is arranged to receive at least a portion of the second further cooled product stream (28).

19. A chemical plant (300) comprising : a syngas stream (311); a product synthesis section (320); the system for distillation according to any one of claims 1-22 (200), wherein said product synthesis section (320) is arranged to receive at least a portion of said syngas stream (311) and output a first raw product stream (1), and37 wherein said system for distillation (200) is arranged to receive said first raw product stream (1) from said product synthesis section (320) and provide a first distilled product stream (71) such as a second portion (72b) of said first distilled product stream (71).

20. The chemical plant (300) according to claim 19, wherein the syngas stream (311) comprises hydrogen, wherein at least a portion of the hydrogen is provided from electrolysis of H2O.

21. The chemical plant (300) according to any one of claims 19-20, being a methanol plant, said methanol plant comprising a methanol synthesis section (320a), said methanol synthesis section (320a) being arranged to receive a syngas stream (311) and output the first raw product stream (1), being a raw methanol stream (1').

22. The chemical plant (300) according to any one of claims 19-21, wherein the plant optionally comprises an e-syngas section, and wherein the e-syngas section and / or the product synthesis section (320) is / are arranged to provide additional heat energy to at least one of i) the first raw product stream (1), ii) the stabilizer column (10a), iii) and / or the first concentration column (20).

23. A method for distillation of a first raw product stream (1), in the system according to any one of claims 1-18, wherein said method comprises: feeding a first raw product stream (1) to the stabilizer section (10) and providing a second raw product stream (11), and a first off-gas stream (12); feeding at least a portion of the second raw product stream (11) to the first concentration column (20), distilling said stream (11) and providing a first vaporised product steam (21) from said first concentration column (20), a first condensate stream (29), and optionally a second off-stream (22); feeding at least a portion of the first product stream (21) and a pure product stream (72a, 73) to the first compressor (30), and providing a second product stream (31) from said first compressor (30); feeding at least a portion of the second product stream (31) to the first reboiler (40), and hereby providing heat energy to the first concentration column (20), wherein the step of providing heat energy to the first concentration column (20) comprises providing heat energy from at least a portion of the second product stream (31) to the first reboiler (40) and providing a cooled third product stream (41) from said first reboiler (40);38 feeding at least a portion of the third product stream (41) to the cooling arrangement (50) to provide the further cooled product stream (60); feeding at least a portion of the further cooled product stream (60) to the drum (70) to provide a first distilled product stream (71).

24. The method according to claim 23, feeding at least a first portion (72a) of said first distilled product stream (71) as a feed to the first compressor (30) and / or feeding a pure product stream from storage (73) such as from a product storage tank as a feed to the first compressor (30).

25. The method according to any one of claims 23-24, wherein the system comprises a second reboiler (51), said method comprising feeding at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream from said first reboiler (40) to the second reboiler (51) and hereby providing heat energy to the stabilizer column (10a), wherein the step of providing heat energy to the stabilizer column (10a) comprises providing heat energy from the at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream to the second reboiler (51).

26. The method according to any one of claim 23-25, wherein the system comprises a second heat exchanger (55), said method further comprises feeding at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream to the second heat exchanger (55) and hereby providing heat energy to the first raw product stream (1), wherein the step of providing heat energy to the first raw product stream (1) comprises providing heat energy from at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream to the second heat exchanger (55).

27. The method according to any one of claims 23-26, wherein the system further comprises a first heat exchanger (58), said method further comprises feeding at at least a portion of the cooled third product stream (41) and / or one or more streams derivable from said cooled third product stream to the first heat exchanger (58) so as to provide at least a portion of the further cooled product stream (60).

28. The method according to any one of claims 23-27, wherein the first compressor (30) comprises one compression stage, said method further comprises feeding at least a subportion of the pure product stream (72a, 73) such as of the first portion (72a) of said first distilled product stream (71) as a feed upstream and / or downstream of the compression stage.3929. The method according to any one of claims 23-27, wherein the first compressor (30) comprises two or more compression stages and said method further comprises feeding one or more sub-stream(s) of the pure product stream (72a, 73) such as of the first portion (72a) of said first distilled product stream (71) to the first compressor (30) between any two compression stages, optionally also before the initial compression stage and / or after the final compression stage.

30. The method according to any one of claims 23-29, wherein the method further comprises operating the first concentration column (20) at a pressure of between 0.1-10.0 bar g, preferably 0.1-1.5 bar g.

31. A method of revamping an existing distillation system comprising the steps of: providing a first compressor configured to receive at least a portion of a first product stream from a first concentration column and pure product stream and output a second product stream, fluidly connect the first compressor to a first concentration column of the distillation system, fluidly connect the first compressor to a pure product stream of the distillation system, fluidly connect an outlet of the first compressor to a first reboiler of the distillation system.

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