Method and plant for acid removal in systems that convert oxygen-containing compounds to hydrocarbons

Abstract

An oxygen-containing supply logistics, for example, a method and plant for producing hydrocarbons from methanol, characterized by removing acid from the converted oxygen-containing compound product before downstream fractional distillation. The plant comprises: an OTH section arranged to receive an oxygen-containing compound and provide a converted oxygen-containing compound product containing the hydrocarbon; an acid removal section arranged to receive the converted oxygen-containing compound product and provide a converted and acid-washed oxygen-containing compound product; and a separation section arranged to receive the converted and acid-washed oxygen-containing compound product and supply at least one of an intermediate gasoline product, an intermediate naphtha product, an intermediate jet fuel product, and an intermediate diesel product.

Description

Technical Field

[0001] The present invention relates to removing acids from a stream containing hydrocarbon products obtained by converting oxygen-containing compounds into hydrocarbons, for example, when converting methanol into hydrocarbons within the transportation fuel range such as gasoline, jet fuel, and optionally diesel fuel.

Background Art

[0002] In conventional processes / plants for converting oxygen-containing compounds into hydrocarbons (OTH processes / plants), such as the process for converting methanol into hydrocarbons (MTH), specifically the process for converting methanol into gasoline (MTG) or the process for converting methanol into olefins (MTO) related to the production of jet fuel (MTJ), catalysts containing acidic zeolites are generally used. The oxygen-containing compounds are usually methanol and / or dimethyl ether (DME).

[0003] For example, in a conventional methanol-to-gasoline (MTG) process, methanol is converted in an MTG reactor in the presence of a catalyst containing an acidic zeolite, such as a zeolite with a 10-membered ring pore structure (the 10-membered ring pore structure is a three-dimensional (3D) pore structure such as ZSM-5). From the MTG reactor, the converted crude oxygenated compound product (i.e., the first crude gasoline product), which contains hydrocarbons boiling in the gasoline boiling point range, is withdrawn as the converted crude oxygenated compound product and supplied to a three-phase separation unit. From this separation unit, a process condensate containing water and oxygenated compounds, a top flow usable as a recycle flow, and the converted oxygenated compound product (i.e., crude gasoline product) are separated. The oxygenated compounds in the process condensate include unconverted oxygenated compounds (e.g., unconverted methanol) and acids such as formic acid and acetic acid. The recycle flow from the separation unit is led to the MTG reactor via a recycle compressor (MTG loop). The crude gasoline product is fed to a downstream separation section, such as a fractional distillation unit, where C2-C4 compounds are typically removed in a so-called de-ethanizer and de-butanizer (LPG separator), thereby obtaining a stabilized gasoline product as an intermediate gasoline product. The stabilized gasoline product is further modified by hydroisomerization (HDI) and / or hydrocracking (HCR) to supply the final gasoline product.

[0004] For example, in the methanol-to-jet fuel (MJT) process, methanol is converted in an MTO reactor in the presence of a catalyst containing an acidic zeolite, such as a zeolite with a 10-membered ring pore structure (the 10-membered ring pore structure is a one-dimensional (1D) pore structure such as ZSM-48). From the MTO reactor, the converted crude oxygen-containing compound product, containing hydrocarbons in the jet fuel boiling point range, is withdrawn and fed to a three-phase separation unit. From this separation unit, the process condensate containing water and oxygen-containing compounds is separated, as well as the top flow usable as a recycle flow and the converted oxygen-containing compound product. The recycle flow is appropriately guided back to the MTO reactor via a recycle compressor, forming an MTO loop. The converted oxygen-containing compound product, containing hydrocarbons in the jet fuel boiling point range, is typically fed sequentially to an oligomerization section to further generate hydrocarbons in the jet fuel boiling point range, and then to downstream separation sections such as fractional distillation sections for separating intermediate naphtha products, intermediate jet fuel products, and optionally intermediate diesel products. Intermediate jet fuel can be further subjected to hydrogenation, for example, to saturate the olefins and produce the final jet fuel product.

[0005] Until now, it has been common practice to remove undesirable oxygen-containing compounds such as unconverted methanol and organic acids, such as the aforementioned formic acid and acetic acid, as part of the process condensate stream drawn from the three-phase separator. This process condensate is usually sent to a stripper (PC stripper) to recover methanol as an oxygen-containing compound, and the remaining oxygen-containing compounds in the process condensate are sent to a wastewater treatment plant.

[0006] The process condensate contains acids in the ppm range, and it has now been found that these acids also migrate to the hydrocarbon phase of the three-phase separator. As a result, the separated, converted oxygenated compound products become extremely corrosive when exposed to free water. Surprisingly, even when water separation in the three-phase separator is effective, undesirable oxygenated compounds, particularly organic acids, still remain in the hydrocarbon phase. Consequently, these highly corrosive converted oxygenated compound products necessitate the use of expensive stainless steel in downstream equipment. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] US20200239785A1 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] US20200239785A1 discloses a system for removing organic acids from liquid hydrocarbon product streams. This involves injecting an ammonia aqueous wash into a liquid hydrocarbon product stream, such as an effluent from a methanol conversion process, and then separating the treated liquid hydrocarbon product stream from the wash water. The addition of ammonia unexpectedly reduces the amount of wash water. This cited document does not mention, at least not, the conversion of the wash water recycling into a bleed stream, and the combination of this bleed stream with a process condensate containing water and oxygen-containing compounds from an upstream separation unit to form a combined process condensate stream. [Means for solving the problem]

[0009] Therefore, in a first aspect of the present invention, a method for converting an oxygen-containing compound into a hydrocarbon is provided, comprising the following steps: - A step of supplying one or more oxygen-containing compounds to a section (OTH section) that converts oxygen-containing compounds to hydrocarbons, and from there providing a converted oxygen-containing compound product containing the hydrocarbons, wherein the OTH section includes an oxygen-containing compound conversion reactor and a separation unit in the presence of a conversion catalyst containing zeolite. - A step in the oxygen-containing compound conversion reactor to convert a supply logistics containing one or more oxygen-containing compounds into a converted crude oxygen-containing compound product; - In the separation unit, a step of separating the converted crude oxygen-containing compound product into at least: a process condensate containing water and oxygen-containing compounds; and the converted oxygen-containing compound product; Furthermore, this method includes the following steps: - A step of supplying the converted oxygen-containing compound product to an acid removal step to provide the converted and acid-washed oxygen-containing compound product; - A step of supplying the converted and acid-washed oxygen-containing compound products to a separation section and separating at least one of the following from the converted and acid-washed oxygen-containing compound products: intermediate gasoline products, intermediate naphtha products, intermediate jet fuel products, intermediate diesel products, and optionally an off-gas stream (33), an off-gas stream containing, for example, C1-C4 hydrocarbons, such as LPG. Here, the acid removal step includes the following steps: - The converted oxygen-containing compound is combined with recycled wash water containing an alkaline agent to form a combined flow; in this step, the first recycled wash water is drawn from a downstream filtration unit and combined with the alkaline agent to form the recycled wash water; - A step of supplying the combined flow to the mixing unit and then to the filtration unit; - A step of extracting the recycled wash water and the converted and acid-washed oxygen-containing compound products from the filtration unit; Furthermore, this method includes the following: - A portion of the recycled wash water is redirected as a bleed flow, and this bleed flow is combined with the process condensate containing water and oxygen-containing compounds to form a combined process condensate flow.

[0010] By removing acids from the oxygen-containing compound products converted from the separation unit, downstream units such as the separation section can be made of carbon steel instead of stainless steel, thereby significantly reducing capital expenditures (CAPEX) and operating costs (OPEX).

[0011] In one embodiment, the oxygen-containing compound is methanol (MeOH) and / or dimethyl ether (DME).

[0012] The present invention enables the separation of unconverted oxygen-containing compounds, particularly methanol (MeOH) and / or dimethyl ether (DME), using a single process condensate stripper (PC stripper). The separated oxygen-containing compounds can then be introduced into oxygen-containing compound conversion reactors in the OTH section, such as methanol-to-gasoline (MTG) reactors, methanol-to-olefin (MTO) reactors, or more generally, methanol-to-hydrocarbon (MTH) reactors, without the risk of introducing ammonia compounds into the reactor. Separation is not required; that is, there is no need to provide a separate, dedicated PC stripper for treating wash water containing ammonia. The MTH reactor contains an acidic zeolite as a catalyst, which reversibly reacts with ammonia to deactivate the catalyst. The catalyst cycle time is shortened, and this increases the frequency of regeneration to remove ammonia from the catalyst. As a result, the catalyst life is also shortened.

[0013] In one embodiment, the method further comprises supplying a combined process condensate stream to a process condensate stripping unit (PC stripper) and recovering from there: a top gas stream containing unconverted oxygen-containing compounds (such as unconverted methanol and / or DME) that do not contain an alkaline agent; and a bottom stream containing the alkaline agent.

[0014] The term "alkaline agent-free" is understood to mean that the alkaline agent is either undetectable or present in a concentration or amount that does not inactivate the conversion catalyst in the oxygen-containing compound conversion reactor.

[0015] A PC stripper is understood to be a general-purpose PC stripper that handles combined flows of process condensates; see, for example, flow 9' in the attached diagram.

[0016] As is well known to those skilled in the art, a PC stripper (PC stripping unit) is a device that removes impurities from process condensate. These impurities include unconverted oxygen-containing compounds such as methanol and DME, and acidic compounds such as formic acid and acetic acid. In a PC stripper, heat and, if necessary, pressure are supplied to heat and pressurize the process condensate. However, it is preferable that the PC stripper is operated at a lower pressure than the synthesis apparatus. This vaporizes the impurities, which are separated from the rest of the process condensate as a top gas flow, and the latter is discharged as a bottom flow. This process condensate is then sent to a wastewater treatment plant.

[0017] It will be understood that acids, specifically organic acids, are also drawn out (discharged) from the PC stripper along with the bottom flow.

[0018] In one embodiment, the method further comprises: supplying the top gas stream containing unconverted oxygen-containing compounds without an alkaline agent, such as unconverted methanol and / or DME, to the oxygen-containing compound conversion reactor.

[0019] According to the present invention, for example, sodium ions (Na-ions) of an alkaline agent are present in the combined process condensate stream, condense in a common PC stripper, and are withdrawn together with the bottom stream of the PC stripper. Therefore, unlike ammonia compounds, for example, Na ions are not carried over with the unconverted oxygen-containing compounds (e.g., unconverted methanol) withdrawn in the overhead gas of the PC stripper, but are reused as an oxygen-containing compound feed in the oxygen-containing compound converter in the OTH section. If these ions are carried over with the unconverted oxygen-containing compounds, the ions deactivate the MTG catalyst and shorten the catalyst cycle time.

[0020] When ammonia is present in the combined process condensate and sent to the PC stripper, some ammonia is withdrawn together with the bottom stream of the PC stripper, and some ammonia is withdrawn as part of the overhead gas of the PC stripper together with the unconverted oxygen-containing compounds, e.g., unconverted methanol, which deactivates the catalyst of the MTH reactor. Before returning the unconverted oxygen-containing compounds to the MTH reactor, further ammonia removal is required, which results in high penalties in terms of both capital expenditure and operating costs. Furthermore, ammonia as an alkaline agent in the acid removal step, or the corresponding acid removal system, is more difficult to handle and requires considerable safety measures because ammonia is extremely volatile.

[0021] Na ions condensed in a common PC stripper are recovered in the bottom stream sent to a wastewater treatment plant (WWTP). Sodium ions contribute to the conductivity of the wastewater, which promotes specific treatment processes such as electrocoagulation in the WWTP, and the higher the conductivity, the more effectively suspended particles in the water can be removed.

[0022] In one embodiment, the step of diverting a portion of the wash water recycle as a bleed stream is performed prior to the step of combining the alkaline agent and the wash water recycle.

[0023] For the purposes of this application, the term "first aspect of the invention" means the method of the invention. The term "second aspect of the invention" means a plant (system), i.e., a process plant. The term "method for converting an oxygen-containing compound to a hydrocarbon" can be used interchangeably with the term "OTH process". The term "OTH section" means a physical section composed of one or more units such as a reactor and a separation unit and related process steps. It should be understood that the OTH section is a physical section of the OTH process / plant. The OTH process / plant includes the OTH section. For example, the MTG process / plant includes the MTG section. The term "process / plant" means a process and / or a plant.

[0024] The term "and / or" means any one of three options in relation to a given embodiment example. Thus, the term "and / or" can be used interchangeably with the term "at least one" among the three options. The term "comprises" includes "comprises only", i.e., "consists of". The term "appropriately" is used interchangeably with "any", i.e., any embodiment example. The term "the present invention" or simply "the invention" can be used interchangeably with the term "the present application" or simply "the application". "LPG" means liquefied petroleum gas well-known in the technical field and refers to a C3-C4 hydrocarbon fraction. Other definitions are provided in relation to one or more of the following embodiment examples.

[0025] In one embodiment example, the separation unit further provides a top recycle stream, and the method further includes recycling the top recycle stream to the oxygen-containing compound conversion reactor, for example, mixing it with a feed stream of one or more oxygen-containing compounds to form a combined feed stream.

[0026] As a result, the OTH section, for example, the MTG section, functions as an MTG loop section. A dedicated recycle compressor supplies a top recycle flow to the oxygen-containing compound conversion reactor, in this case the MTG reactor, and controls the exothermic nature of the MTG reaction taking place there. In another embodiment, the OTH section, for example, the MTO section, operates as an MTO loop section. A dedicated recycle compressor supplies a top recycle flow to the oxygen-containing compound conversion reactor, in this case the MTO reactor, and controls the exothermic nature of the MTO reaction taking place there.

[0027] According to the present invention, the acid removal step includes the following: -The converted oxygen-containing compound product is combined with wash water recycling containing an alkaline agent to form a combined flow; here, the first wash water recycling is drawn from the downstream filtration unit and combined with the alkaline agent to form the wash water recycling; - The combined flow is supplied to the mixing device, and then to the filtration unit; -The recycled wash water and the converted and acid-washed oxygen-containing compound products are extracted from the filtration unit.

[0028] This makes it possible to remove acid by simple water washing, even if acid is present at ppmw levels in the converted oxygen-containing compound product.

[0029] In one embodiment, the alkaline agent is a caustic agent (corrosive agent). In one embodiment, the caustic agent is either NaHCO3 or Na2CO3.

[0030] The term "caustic agent" refers to a strong base derived from sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), or a combination thereof. The term "caustic agent" does not include ammonia or ammonia compounds. Ammonia itself is considered a weak base.

[0031] In one embodiment, the downstream filtration unit is a coalescer, the mixing unit is a static mixer, i.e., a liquid / liquid static mixer, and the alkaline agent is the caustic agent, for example, NaHCO3 or Na2CO3; the acid removal step further includes supplying the alkaline agent by a metering and supplying unit (e.g., a caustic agent metering and supplying unit) and combining it with the wash water recycling.

[0032] A simple water wash using an alkaline agent, for example, an additive of a caustic agent, is provided thereby. The wash water is mixed with the converted oxygen-containing compound product after the aqueous phase, which is mainly removed from the process condensate, is separated in a separation unit, preferably a three-phase separator. For example, a 10% by mass wash water recycling with the addition of alkali is provided. The mixture is sent to a static mixer, i.e., a system consisting of one or more static mixers, to ensure good contact between the acid and the alkaline agent. The mixture is then sent to a coalescer to effectively separate the wash water. The washed hydrocarbon product, as a converted and acid-washed oxygen-containing compound product, is sent to a downstream separation section, for example, a fractional distillation section including one or more fractional distillation units.

[0033] According to the present invention, the method further includes: optionally, prior to the step of combining the alkaline agent and the wash water recycling liquid, a portion of the wash water is redirected as a bleed flow, the bleed flow is combined with a process condensate containing water and oxygen-containing compounds to form a combined process condensate flow; optionally, the combined process condensate flow is supplied to a process condensate stripping unit (PC stripper).

[0034] The wash water is recycled to the mixing point, while a small amount of bleed corresponding to the amount of alkali added is sent to the process condensate stripper.

[0035] In one embodiment, the converted and acid-washed oxygen-containing compound product contains an acid of less than 1 ppmw, for example, an acid of less than 0.6 ppmw, for example, an acid of less than 0.01 ppmw, and the acid is at least one of formic acid, acetic acid, propionic acid, or a combination thereof.

[0036] The residual acid in the converted and acid-washed oxygen-containing compound products was found to be less than 1 ppmw, and even less than 0.6 ppmw, which is the detection limit; furthermore, the present invention makes it possible to achieve significantly lower values, for example, less than 0.01 ppmw.

[0037] In one embodiment, the converted and acid-washed oxygen-containing compound comprises C5+ (C5 or greater) hydrocarbons, wherein at least 30% by mass, for example, at least 40% by mass, or at least 50% by mass, are hydrocarbons that boil in the gasoline boiling range and / or C5+ hydrocarbons that boil in the jet fuel boiling range.

[0038] Therefore, the present invention is suitable for at least MTG plants and MTJ processes / plants, which enable the use of carbon steel or other materials that are less expensive than stainless steel in downstream units such as separation sections, which may include one or more fractional distillation units, such as distillation units. These units (equipment) are very expensive in terms of both capital expenditure (CAPEX) and operating costs (OPEX).

[0039] The term "hydrocarbons that boil within the gasoline boiling point range" refers to C5-C12 hydrocarbons that boil within the range of 30-210°C. The term “jet fuel boiling point range hydrocarbons” can be used interchangeably with “jet fuel hydrocarbons” or “jet fuel range hydrocarbons,” or respectively with “jet fuel” or “jet fuel range.” This term refers to C8–C19 hydrocarbons, e.g., C8–C17 or C8–C16 hydrocarbons, that boil in the range of 130–300°C. For example, jet fuel is a sustainable aviation fuel (SAF) compliant with ASTM D7566 and ASTM D4054.

[0040] The term "boiling within a specified range" is understood to mean a hydrocarbon mixture in which at least 80% by mass boils within the specified range. The intermediate naphtha product contains C5-C9 hydrocarbons (e.g., C5-C8 hydrocarbons, e.g., C5-C8 olefins, etc.) that boil in the range of 30-160°C. The intermediate diesel products include C8-C25 hydrocarbons that boil within the diesel boiling range, i.e., 120-360°C (e.g., 160-360°C).

[0041] In gasoline production (e.g., MTG process / plant), the converted and acid-washed oxygen-containing compound products are sent as a crude gasoline stream to a downstream separation section including a de-ethane and de-butane unit (LPG separator), which produces a stabilized gasoline stream as an intermediate gasoline product. As is well known in the art, the de-ethane and LPG separators are preferably fractional distillation units, such as distillation units. The stabilized gasoline is reformed (upgraded) by hydroisomerization (HDI) in an HDI reactor and / or hydrocracking (HCR) in an HCR reactor to obtain the final gasoline product.

[0042] In jet fuel production (e.g., MTJ process / plant), the converted and acid-washed oxygen-containing compounds are sent to a downstream separation section. The downstream separation section includes one or more fractional distillation units, thereby providing intermediate naphtha products, intermediate jet fuel products, and possibly intermediate diesel products. The intermediate jet fuel products are appropriately sent to a hydrotreatment, preferably a hydro (HYDRO) treatment, to saturate the olefins in the jet fuel with the corresponding paraffins, thereby yielding the final jet fuel product.

[0043] In either MTG or MTJ, an off-gas flow is withdrawn. An off-gas flow refers to one or more off-gas flows. Off-gas flows include, for example, CO, CO2, and H2. Off-gas flows also include, for example, C1-C4 hydrocarbons such as LPG. Combinations of these are also possible.

[0044] It is understood that the OTH section can be provided as either a once-through (single-pass) OTH section or an OTH loop section. In the example embodiment, it will be understood that the OTH section may become the MTH section.

[0045] In this embodiment, the MTH section is understood to be an MTH loop section. The term MTH is understood to encompass either MTG, MTO, or MTJ. It is understood that MTJ may optionally include oligomerization (OLI) of MTO. It is understood that MTH means methanol to hydrocarbon conversion; MTG means methanol to gasoline conversion; MTO means methanol to olefin conversion; and MTJ means methanol to jet fuel conversion.

[0046] On the other hand, OTH sections, such as MTG sections and MTO sections, can be provided in once-through mode (without recycling of top flow from the isolation unit, and therefore without a recycle compressor), but it is advantageous to provide them as loops with recycling of top flow from the isolation unit (and therefore with a recycle compressor).

[0047] Therefore, in one embodiment, - The OTH section is a methanol-to-gasoline loop section (MTG loop section), and in the OTH section, the zeolite is a zeolite having a skeleton with a 10-membered ring pore structure, and the 10-membered ring pore structure is a three-dimensional (3D) pore structure, such as ZSM-5; or - The OTH section is a methanol-to-olefin loop section (MTO loop section), and in the OTH section, the zeolite is a zeolite having a skeleton with a 10-membered ring pore structure, and the 10-membered ring pore structure is a one-dimensional (1D) pore structure, such as ZSM-48.

[0048] For example, the MTG reactor in the MTG loop section is provided as an adiabatic fixed-bed reactor, and the catalyst contains a zeolite having a skeleton with a 10-membered ring pore structure, the 10-membered ring pore structure being a three-dimensional (3D) pore structure, such as ZSM-5. The exothermic nature of the MTG reactor can be controlled by top-of-column recycling.

[0049] For example, the MTO reactor in the MTO loop section is provided as an adiabatic fixed-bed reactor using a zeolite catalyst having a 10-membered ring pore structure, such as ZSM-48, where this 10-membered ring pore structure is a one-dimensional (1D) pore structure. The exothermic nature of the MTO reactor can be controlled by top-of-column recycling.

[0050] In one embodiment, following the separation section, for example, the fractional distillation section, a downstream hydrogenation treatment is carried out in a hydrogenation section or unit in the presence of a hydrogenation catalyst. For example, to reform an intermediate gasoline product into a final gasoline product, hydrogenation isomerization (HDI) in an HDI reactor in the presence of an HDI catalyst and / or hydrogen cracking (HCR) in an HCR reactor in the presence of an HCR catalyst can be provided. For example, to hydrogenate an intermediate jet fuel product into a final jet fuel product, hydrogenation (HYDRO) in a HYDRO reactor in the presence of a HYDRO (hydrogenation) catalyst is provided. Suitable conditions and catalysts for hydrogenation treatments (e.g., HDI, HCR) and HYDRO are well known to those skilled in the art.

[0051] As a second aspect of the present invention, a plant for carrying out the method according to any of the above embodiments is also provided.

[0052] Therefore, a plant for converting oxygen-containing compounds into hydrocarbons is provided, and the plant includes: - An OTH section comprising an oxygen-containing compound conversion reactor and a separation unit: The OTH section is configured to receive a feed stream containing one or more oxygen-containing compounds and provide a converted oxygen-containing compound product; the OTH section comprises an oxygen-containing compound conversion reactor (12) and a separation unit (14) in the presence of a conversion catalyst (12') containing zeolite, wherein the oxygen-containing compound conversion reactor (12) is configured to receive a feed stream of one or more oxygen-containing compounds (1) and provide a converted crude oxygen-containing compound product (7); the separation unit (14) is configured to receive the converted crude oxygen-containing compound product (7) and provide at least: a process condensate (9) containing water and oxygen-containing compounds; and the converted oxygen-containing compound product (11); - An acid removal section comprising a filtration unit, a mixing unit upstream of the filtration unit, and optionally a metering and dispensing unit (20); the acid removal section is arranged to receive the converted oxygen-containing compound product and provide the converted and acid-washed oxygen-containing compound product (23); - A separation section, for example, a fractional distillation section, which is arranged to receive the converted and acid-washed oxygen-containing compounds (: intermediate gasoline products, intermediate naphtha products, intermediate jet fuel products, intermediate diesel products, and optionally an off-gas stream containing C1-C4 hydrocarbons, for example, LPG; Here, the acid removal section is, - A mixing point, e.g., a confluence point, for combining the converted oxygen-containing compound product with recycled wash water containing an alkaline agent to form a combined flow; a conduit for drawing the first recycled wash water from the filtration unit, and a mixing point, e.g., a confluence point, for combining the first recycled wash water with the alkaline agent to form the recycled wash water; - Conduits for supplying the combined flow to the mixing unit and subsequently to the filtration unit; - Recycling the wash water and extracting the converted and acid-washed oxygen-containing compound products from the filtration unit; Further including: The aforementioned plant, - A conduit for redirecting a portion of the recycled wash water as a bleed flow, and a mixing point, such as a confluence point, for combining the bleed flow with the process condensate containing water and oxygen-containing compounds to form a combined process condensate flow, It also includes.

[0053] In one embodiment, the plant further comprises a process condensate stripping unit (PC stripper) that receives the combined process condensate stream and provides: a top gas stream containing unconverted oxygen-containing compounds without an alkaline agent, such as unconverted methanol and / or DME; and a bottom stream containing the alkaline agent.

[0054] It is understood that acids, specifically organic acids, are also drawn out as part of the bottom flow from the PC stripper. This bottom flow is then supplied to the wastewater treatment plant.

[0055] The term "conduit" is understood to mean a process line (e.g., a pipe) that transports a given process flow.

[0056] In one embodiment, the plant further comprises conduits for supplying the top gas stream containing unconverted oxygen-containing compounds without an alkaline agent, such as unconverted methanol and / or DME, to the oxygen-containing compound conversion reactor.

[0057] In one embodiment, the downstream filtration unit is a coalescer, the mixing unit is a static mixer, i.e., a liquid / liquid static mixer, the alkaline agent is a caustic agent, such as NaHCO3 or Na2CO3, the acid removal section further includes a mixing point, such as a confluence point, for mixing the alkaline agent and the wash water recycle, and the acid removal section further includes a metering and dispensing unit, such as a caustic agent metering and dispensing unit, for supplying the alkaline agent.

[0058] Any embodiment and related advantages of the first aspect (method) of the present invention can be used in relation to the second aspect (plant) of the present invention, and vice versa.

[0059] The attached drawings (Figures) show a method / plant 10 for converting oxygen-containing compounds to hydrocarbons according to an embodiment of the present invention. The plant (OTH plant) 10 comprises an OTH section, an acid removal section, and a separation section, as shown below. The OTH section is provided as an OTH loop section, in particular an MTH loop section, more specifically an MTG loop section or an MTO loop section. As shown in the Figures, the MTH loop section comprises an MTH reactor 12 as a reactor for converting oxygen-containing compounds, an associated adiabatic fixed-bed catalyst 12' containing zeolite, and a separation unit 14, e.g., a three-phase separator, a top recycler 3, 3', and a dedicated recycle compressor. Downstream, there is an acid removal section, which comprises a mixing unit 16, e.g., a static mixer 16 (liquid / liquid static mixer), a filtration unit 18, e.g., a coalescer, a metering and feeding unit 20, and wash water recyclers 17, 21, 21'. Further downstream, there is also a separation section 22, which optionally comprises one or more fractional distillation units. Therefore, the OTH plant 10 in this embodiment comprises an MTG loop section or an MTO loop section, as well as an acid removal section and a downstream separation section.

[0060] In the OTH section, a feed of one or more oxygen-containing compounds 1, such as methanol, is included and mixed with, for example, the upper recycle flow 3', and introduced into the MTH reactor 12 as a combined feed flow 5. This reactor 12 is equipped with a catalyst 12', the catalyst containing zeolite. The converted crude oxygen-containing compound product 7 is withdrawn and sent to the separation unit 14. There, the top recycle 3 is separated, and the process condensate 9 containing water and oxygen-containing compounds is separated. The oxygen-containing compounds include unreacted methanol and acids such as formic acid and acetic acid. Furthermore, the converted oxygen-containing compound product 11 is also separated as a hydrocarbon fraction in the separation unit 14. This converted oxygen-containing compound product 11 still contains the aforementioned acids such as formic acid and acetic acid, and other organic acids.

[0061] The flow 11 is combined with the wash water recycle 21' from the downstream coalescer 18 to form a combined flow 13, which is then removed in the acid removal step in the acid removal section. In this embodiment, the acid removal section comprises a liquid / liquid static mixer 16, a coalescer 18, and a metering and supply unit 20. The combined flow 13 is supplied to the liquid / liquid static mixer 16 to become flow 15, which is then supplied to the coalescer 18. From the coalescer 18, the wash water recycle flow 17 and the converted and acid-washed oxygen-containing compound products 23 are withdrawn (discharged). The alkaline agent 19 from the metering and supply unit 20 is combined with the wash water recycle 17 to form a wash water recycle flow 21 containing the alkaline agent. Furthermore, a portion of the wash water recycle 17, 21 is redirected as a bleed flow 21'', which is then combined with the process condensate 9. This combined process condensate flow 9' is appropriately supplied to a process condensate stripping unit (PC stripper, not shown). The PC stripper is configured to receive a combined process condensate flow 9' and produce the following: a top gas flow containing unconverted oxygen-containing compounds without an alkaline agent, e.g., unconverted methanol and / or DME; and a bottom flow (not shown) containing an alkaline agent. Acids, i.e., organic acids, are also drawn out as part of the bottom flow from the PC stripper. This bottom flow is then supplied to a wastewater treatment plant (not shown). Furthermore, a conduit (not shown) may be provided for supplying the top gas flow containing unconverted oxygen-containing compounds without an alkaline agent, e.g., unconverted methanol and / or DME, to the oxygen-containing compound conversion reactor 12.

[0062] Downstream of the acid removal section, the converted and acid-washed oxygen-containing compound 23 is fed to a separation section (shown here simply as section 22), which is suitable for a fractional distillation section comprising one or more fractional distillation units, to separate at least one of the following: intermediate naphtha products 25, 25', 25'', intermediate gasoline product 27, intermediate jet fuel product 29, and intermediate diesel product 31. An off-gas stream 33, containing C1-C4 hydrocarbons such as LPG, may also be withdrawn. Downstream of the separation section 22, a hydrogenation treatment (not shown), such as hydrogenation, is performed to obtain, for example, the final jet fuel product.

Claims

1. The following steps: - A step of supplying one or more oxygen-containing compounds (1) to a section (OTH section) that converts oxygen-containing compounds to hydrocarbons, thereby providing a converted oxygen-containing compound product (11) containing the hydrocarbons, wherein the OTH section includes an oxygen-containing compound conversion reactor (12) in the presence of a conversion catalyst (12') containing zeolite, and a separation unit (14); - A step in which a supply flow containing one or more oxygen-containing compounds (1) is converted into a converted crude oxygen-containing compound product (7) in the oxygen-containing compound conversion reactor (12); - In the separation unit (14), the step of separating the converted crude oxygen-containing compound product (7) into at least: a process condensate (9) containing water and oxygen-containing compounds; and the converted oxygen-containing compound product (11); A method (10) for converting an oxygen-containing compound containing a hydrocarbon, Furthermore, it includes the following steps: - A step of supplying the converted oxygen-containing compound product (11) to an acid removal step to provide a converted and acid-washed oxygen-containing compound product (23); - A step of supplying the converted and acid-washed oxygen-containing compound product (23) to a separation section (22) and separating at least one of the following from the converted and acid-washed oxygen-containing compound product (23): intermediate gasoline product (27), intermediate naphtha product (25, 25', 25''), intermediate jet fuel product (29), intermediate diesel product (31), and optionally off-gas stream (33), for example, an off-gas stream containing C1-C4 hydrocarbons; Here, the acid removal step includes the following steps: - The converted oxygen-containing compound product (11) is combined with wash water recycling (21, 21') containing an alkaline agent (19) to form a combined flow (13); in this step, the first wash water recycling (17) is withdrawn from the downstream filtration unit (18) and combined with the alkaline agent (19) to form the wash water recycling (21, 21''); - A step of supplying the combined flow (13) to the mixing unit (16), and then to the filtration unit (18); - A step of withdrawing the wash water recycling (17) and the converted and acid-washed oxygen-containing compound product (23) from the filtration unit (18); Furthermore, the method - The method comprising the steps of redirecting a portion of the wash water recycling (17, 21) as a bleed flow (21''), and combining the bleed flow (21'') with the process condensate (9) containing water and oxygen-containing compounds to form a combined process condensate flow (9').

2. The combined process condensate stream (9') is supplied to a process condensate stripping unit (PC-stripper), from which the following are withdrawn: a top gas stream containing unconverted oxygen-containing compounds without an alkaline agent, such as unconverted methanol and / or DME; and a bottom stream containing the alkaline agent. The method according to claim 1, further comprising:

3. The step of supplying the top gas stream of the column, which contains unconverted oxygen-containing compounds without an alkaline agent, for example, unconverted methanol and / or DME, to the oxygen-containing compound conversion reactor (12), The method according to claim 2, further comprising:

4. The method according to any one of claims 1 to 3, wherein the step of redirecting a portion of the wash water recycling (17, 21) as a bleed flow (21'') is performed before the step of combining the alkaline agent (19) with the wash water recycling (17).

5. The method according to any one of claims 1 to 4, further comprising: the separation unit (14) further providing a top-of-column recycle flow (3, 3'); and recycling the top-of-column recycle flow (3, 3') to the oxygen-containing compound conversion reactor (12) by mixing it with the supply flow of, for example, one or more oxygen-containing compounds (1) to form a combined supply flow (5).

6. The alkaline agent is a caustic agent, for example, NaHCO3 ３ or Na ２ CO ３ The method according to any one of claims 1 to 5, wherein the method is any one of the above.

7. The downstream filtration unit (18) is a coalescer, the mixing unit (16) is a static mixer, and the alkaline agent (19) is the caustic agent, for example, NaHCO3 ３ or Na ２ CO ３ The acid removal step further includes combining the alkaline agent (19) with the wash water recycling (17) by providing the alkaline agent (19) through a metering and supplying unit (20), for example, a caustic agent metering and supplying unit. The method according to claim 6.

8. The method according to any one of claims 1 to 7, wherein the converted and acid-washed oxygen-containing compound product (23) comprises an acid of less than 1 ppm W, for example, an acid of less than 0.6 ppm W, for example, an acid of less than 0.01 ppm W; and the acid is at least one of formic acid, acetic acid, propionic acid, or a combination thereof.

9. The method according to any one of claims 1 to 8, wherein the converted and acid-washed oxygen-containing compound product (23) comprises a C5+ (C5 or more) hydrocarbon, and at least 30% by mass, for example, at least 40% by mass, or at least 50% by mass is a hydrocarbon that boils in the gasoline boiling range and / or a hydrocarbon that boils in the jet fuel boiling range.

10. - The OTH section is a methanol-to-gasoline loop section (MTG loop section), and in the OTH section, the zeolite is: a zeolite having a skeleton with a 10-membered ring pore structure, wherein the 10-membered ring pore structure is a three-dimensional (3D) pore structure, such as ZSM-5; or - The OTH section is a methanol-to-olefin loop section (MTO loop section), and in the OTH section, the zeolite is: a zeolite having a skeleton with a 10-membered ring pore structure, wherein the 10-membered ring pore structure is a one-dimensional (1D) pore structure, for example, ZSM-48. The method according to any one of claims 1 to 9.

11. A plant (10) for carrying out the method according to any one of claims 1 to 10; - An OTH section comprising an oxygen-containing compound conversion reactor (12) and a separation unit (14): The OTH section is configured to receive a feed stream of one or more oxygen-containing compounds (1) and to supply a converted oxygen-containing compound product (11); the OTH section comprises an oxygen-containing compound conversion reactor (12) and a separation unit (14) in the presence of a conversion catalyst (12') comprising zeolite, wherein the oxygen-containing compound conversion reactor (12) is configured to receive a feed stream of one or more oxygen-containing compounds (1) and to provide a converted crude oxygen-containing compound product (7); the separation unit (14) is configured to receive the converted crude oxygen-containing compound product (7) and to provide at least: a process condensate (9) containing water and oxygen-containing compounds; and the converted oxygen-containing compound product (11); - An acid removal section comprising a filtration unit (18), a mixing unit (16) upstream of the filtration unit (18), and optionally a metering and dispensing unit (20); the acid removal section is arranged to receive the converted oxygen-containing compound product (11) and provide the converted and acid-washed oxygen-containing compound product (23); - Separation section (22), for example, fractional distillation section, which receives the converted and acid-washed oxygen-containing compounds (23): intermediate gasoline products (27), intermediate naphtha products (25, 25', 25''), intermediate jet fuel products (29), intermediate diesel products (31), and optionally off-gas streams (33), for example off-gas streams containing C1-C4 hydrocarbons, and is configured to provide at least one of these; Includes, Here, the acid removal section is - A mixing point, e.g., a confluence point, for combining the converted oxygen-containing compound product (11) with wash water recycle (21, 21') containing an alkaline agent (19) to form a combined flow (13); a conduit for drawing the first wash water recycle (17) from the filtration unit (18); and a mixing point, e.g., a confluence point, for combining the first wash water recycle (17) with the alkaline agent (19) to form the wash water recycle (21, 21''); - Conduits for supplying the combined flow (13) to the mixing unit (16) and subsequently to the filtration unit (18); - Extracting the recycled wash water (17) and the converted and acid-washed oxygen-containing compound products (23) from the filtration unit (18); Further including: The aforementioned plant (10) - A conduit for redirecting a portion of the wash water recycling (17, 21) as a bleed flow (21''), and a mixing point, for example a confluence point, for combining the bleed flow (21'') with the process condensate (9) containing water and oxygen-containing compounds to form a combined process condensate flow (9'), The plant further includes the aforementioned plant.

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