Process for producing olefins and BTX aromatics from oxygenates

Abstract

The present invention relates to a process (OTO) and a plant for producing olefins from oxygenates, wherein it is also intended to optimize the yields of BTX aromatic benzene, toluene and isoxylenes at the same time. According to the invention, for this purpose a gasoline fraction obtained in an OTO process according to the prior art is added to the aromatization reactor. Multi-stage separation of the product stream from the aromatization reactor provides a product stream containing BTX aromatics and a gasoline fraction from which olefins, naphthenes, and cycloalkenes have been removed.

Description

Technical Field

[0001] The present invention relates to a method and a device for preparing olefins from oxygenates (OTO), wherein the yield of the BTX aromatics benzene, toluene and isoxylenes is also intended to be optimized. Background Art

[0002] Short-chain olefins, such as propylene and ethylene, are among the most important commodities in the chemical industry. The reason for this is that, starting from these unsaturated compounds with a short chain length, it is possible to form molecules with a long-chain carbon skeleton and additional functionalization. These short-chain olefins are widely used in particular in the production of plastics by polymerization.

[0003] The main source of short-chain olefins used to be steam cracking, i.e. thermal cracking in mineral oil processing. However, in the past few years, other processes for preparing short-chain olefins have been developed. One reason for this is that the available sources can no longer meet the growing demand; secondly, the increasing scarcity of fossil raw materials requires the use of different starting materials.

[0004] The so-called MTP (methanol to propylene) or MTO (methanol to olefin) processes for the production of propylene and other short-chain olefins start from methanol as starting material. In general, in this context, the oxygenate-to-olefin (OTO) processes are also referred to, since oxygenated organic components such as methanol or dimethyl ether (DME) are also referred to as oxygenates. Thus, in these heterogeneously catalyzed processes, firstly a dimethyl ether intermediate is formed from, for example, part of the methanol, and subsequently a mixture of ethylene and propylene and hydrocarbons (including olefins) with a higher molar mass is formed from a mixture of methanol and dimethyl ether. In addition, water is present in the product stream, which originates firstly from process steam optionally supplied to the MTO reactor for regulating the reaction and secondly from reaction water produced in the MTP reactor, which is formed as a by-product of the olefin-forming reaction.

[0005] Subsequent purification is primarily aimed at removing unwanted by-products and unconverted reactants and producing the individual hydrocarbon fractions at the highest purity. Typically, a quench system is used in the first step for this purpose. Quenching here means a sudden or rapid cooling, usually by direct heat exchange with a fluid quench medium. If liquids such as water or methanol are used for this purpose, there is also a certain cleaning effect associated with the remaining gas phase.

[0006] An example of purification after an OTO reaction can be found in patent publication DE 10 2014 112 792 A1, which describes how, in a first step, at least one oxygenate is heterogeneously catalytically converted into a product stream comprising C2 olefins, C3 olefins, C4 olefins, C5 / 6 hydrocarbon compounds and C7+ hydrocarbon compounds, and in a second step, a propylene stream consisting of at least 95% by weight of C3 olefins is removed.

[0007] The additional purification unit described in DE 10 2014 112 792 A1 is based on the conventional concept in the art. The quenching may have roughly separated fractions according to the chain length of the obtained olefins due to partial condensation, thereby being able to discharge liquid C4+ fractions from the quenching. The C4- fraction separated in gaseous form is then fed to the compression stage. The C4- fraction from the compression is then sent to a separation device, where C3- hydrocarbons are separated from C4+ hydrocarbons. In the subsequent purification step, the C3 fraction is separated from the C2- fraction in a further separation unit, which must be carried out under pressure due to the low boiling point of these two fractions. In short, since the target is the high purity of the product, the purification of the product stream is complicated. This is applicable to an MTP device with a typical production capacity of about 470kta propylene, but if the device production capacity is lower (100kta or 200kta propylene), it becomes more important. This means that small devices are relatively uneconomical.

[0008] In summary, the products of the MTP process include a propylene product stream, an ethylene product stream and a gasoline fraction, the latter containing higher paraffins, olefins, aromatics and cyclic hydrocarbons. In addition, various hydrocarbons are obtained in the process, in particular a stream containing C4 olefins, C5 olefins and C6+ olefins, which are mainly or completely recycled to the MTP reactor, where they are cracked into short-chain olefins, which improves the yield of the propylene and ethylene target products.

[0009] The main purpose of the MTP process in its current configuration is to maximize the yield of propylene, which is a particularly desirable product. However, there is also a need to increase the yield of other valuable materials, such as aromatics, especially BTX aromatics (benzene, toluene, xylenes), without significantly reducing the yield of the main target products propylene and ethylene.

[0010] To this end, the MTP process and other OTO process configurations known from the prior art have hitherto not provided a satisfactory solution.

[0011] Description of the invention

[0012] It is therefore an object of the present invention to provide a method and an apparatus for preparing short-chain olefins, in particular ethylene and propylene, from oxygenates and additionally producing BTX aromatics, which avoids the disadvantages of the OTO process already mentioned and known in the prior art to date. This object is achieved in a first aspect of the invention by a method having the features of claim 1 and in another aspect of the invention by an apparatus having the features of claim 10. Further aspects of the invention are apparent from the dependent method claims.

[0013] The oxygenate conversion conditions required for the conversion of oxygenate into olefin products are known to those skilled in the art from the prior art, such as the open literature discussed in the introduction. These are the physicochemical conditions under which a measurable conversion of oxygenate to olefins is achieved, preferably an industrially relevant conversion. Those skilled in the art make necessary adjustments to these conditions based on routine experimentation to accommodate respective operating requirements. Any specific reaction conditions disclosed may be used as guidance herein, but they should not be considered as limiting the scope of the invention.

[0014] Thermal separation methods for the purposes of the present invention include all separation methods based on the establishment of thermodynamic phase equilibrium. Distillation or rectification is preferred. However, in principle, other thermal separation methods can also be used, such as extraction or extractive distillation.

[0015] If it is said that a stream comprises hydrocarbons and in particular olefins, this should be taken to mean that olefins are a specific subgroup of hydrocarbons and therefore other non-olefinic hydrocarbons may also be present in the stream.

[0016] Oxygenates are in principle all oxygen-containing hydrocarbon compounds which can be converted under oxygenate conversion conditions into olefins, in particular short-chain olefins such as propene, and other hydrocarbon products. Examples are methanol or dimethyl ether (DME).

[0017] Short-chain olefins in the context of the present invention are in particular olefins which are gaseous under ambient conditions, for example ethylene, propylene and the isomeric butenes 1-butene, cis-2-butene, trans-2-butene, isobutene.

[0018] Higher hydrocarbons or long-chain hydrocarbons in the context of the present invention are particularly hydrocarbons which are liquid in pure form under ambient conditions.

[0019] The hydrocarbon fractions are identified using the following nomenclature: "Cn fraction" refers to a hydrocarbon fraction that contains predominantly hydrocarbons with a carbon chain length of n, i.e. having n carbon atoms. "Cn- fraction" refers to a fraction that contains predominantly hydrocarbons with a carbon chain length of n, but also hydrocarbons with shorter carbon chain lengths. "Cn+ fraction" refers to a fraction that contains predominantly hydrocarbons with a carbon chain length of n, but also hydrocarbons with longer carbon chain lengths. Due to the physical separation method used, such as distillation, the separation according to carbon chain length should not be considered to mean the strict exclusion of hydrocarbons with another chain length. For example, a Cn- fraction, depending on the process conditions of the separation method, may still contain small amounts of hydrocarbons with a carbon number greater than n.

[0020] Unless otherwise stated, the solid, liquid and gas / vapor states of matter mentioned should always be considered relative to the local physical conditions in the respective process step or the respective plant component. In this patent application, the gas and vapor states of matter should be considered synonymous.

[0021] In the present invention, the division or separation / removal of a material stream refers to the generation of at least two substreams from an original material stream, wherein the separation / removal is associated with an intentional change in the physical composition of the resulting substreams relative to the original material stream, for example by applying a thermal separation method or at least a thermal separation step to the original material stream. In contrast, the division of the original material stream is generally not associated with any change in the physical composition of the resulting substreams.

[0022] By gasoline fraction is meant a mixture of substances which is in liquid form under ambient conditions, consists predominantly, preferably substantially entirely, of higher hydrocarbons and which is suitable for use as a gasoline fuel.

[0023] The major part of a fraction, a material stream, etc., is understood to mean a proportion greater in number than the proportions of the other individual components alone. In particular, in the case of binary mixtures or when separating a fraction into two parts, this is understood to mean a proportion greater than 50% by weight, unless otherwise indicated in the specific case.

[0024] The statement that a material stream consists predominantly of one component or a group of components is understood to mean that the molar proportion (mole fraction) or mass proportion (mass fraction) of this component or group of components is greater in quantity than the respective other proportions of the other components or groups of components in the material stream. In particular in the case of binary mixtures, this is understood to mean a proportion of more than 50%. Unless otherwise indicated in the specific case, the basis used here is the mass proportion (mass fraction).

[0025] According to the invention, for this purpose, a gasoline fraction obtained in an MTP process according to the prior art ("MTP gasoline") is added to an aromatization reactor. In one example, the aromatization reactor is configured as a fixed bed reactor and is filled with a bed of a solid particulate aromatization catalyst. In one example, the aromatization reactor is operated in a straight-through manner without recirculation of a product substream.

[0026] According to the invention, the product stream from the aromatization reactor is cooled and partially condensed and then introduced into a phase separation device. A gaseous material stream G2 is discharged from the phase separation device and, in one example, is fed in whole or in part to a compressor. In addition, a liquid material stream A is obtained, from which a product stream containing BTX aromatics is finally obtained by post-treatment in several steps using a thermal separation method.

[0027] First, a liquid substance stream A is fed to a depentanizer, where it is separated into a depentanizer overhead product stream comprising C5- hydrocarbons and a depentanizer bottom product stream comprising C6+ hydrocarbons.

[0028] The depentanizer bottoms product stream is fed into an aromatics separation unit, which is by at least one thermal separation method, such as distillation or extractive distillation or its combined work, and in an example, comprises several knockout towers connected in series. The product obtained from the aromatics separation unit is the first product stream containing non-aromatic hydrocarbons and the second product stream containing BTX aromatics. This is discharged from the technique as a BTX aromatics product stream. According to the specific type of separation method used, the first and / or second product stream can be obtained from corresponding knockout towers as overhead product stream, bottoms product stream or side-draw stream respectively.

[0029] It is particularly advantageous here that the invention provides BTX aromatics as valuable additional materials in good yields without causing any reduction in the yields of the main target products ethylene and propylene, since the BTX aromatics are obtained by further processing of the gasoline fraction from the MTP process according to the prior art. There is a tendency to slightly increase the yields of the main target products ethylene and propylene, since the processing of the gasoline fraction in the aromatization reactor produces as secondary products components which can be fed into the main target product pool.

[0030] Furthermore, the invention improves the usability of the gasoline fraction: Due to its high content of higher or longer-chain olefins and cycloalkanes and cycloalkenes, the gasoline fraction obtained in the MTP process according to the prior art cannot be used directly as a gasoline fuel. However, the treatment of the gasoline fraction in an aromatization reactor according to the invention significantly reduces the concentration of these problematic components, since they are mostly converted into aromatics. After the aromatics have been separated off, what remains is the converted gasoline fraction, which can be added to the hydrocarbon pool for the production of gasoline fuel without any problems.

[0031] Further aspects of the invention

[0032] The second aspect of the present invention is characterized in that, in the process, at least a portion of the gaseous material stream G2 is introduced into a compressor. Since reactive components such as olefins are still present in the gaseous material stream G2, it is possible to further increase the yield of short-chain olefins ethylene and propylene in this way.

[0033] The third aspect of the present invention is characterized in that, in the process, at least a portion of the depentanizer overhead product stream is returned and introduced into the compressor. Since reactive components such as olefins are still present in the depentanizer overhead product stream, it is possible to further increase the yield of short-chain olefins ethylene and propylene in this way.

[0034] A fourth aspect of the invention is characterized in that, in the process, the portion of the depentanizer overhead product stream that is sent back to the compressor is mixed with the reactor product stream before introduction into the compressor. In this way, a more uniform feed stream is obtained for the compressor and concentration fluctuations are avoided. This is particularly important in the case of non-steady states of the process, such as start-up operation, shutdown operation or load changes.

[0035] The fifth aspect of the present invention is characterized in that, in the process, the aromatization conditions include a reactor temperature between 380 and 510° C., a reactor pressure between 1 and 6 bar, and the presence of a solid aromatization catalyst. Studies have shown that these aromatization conditions are particularly suitable for achieving high yields of BTX aromatics.

[0036] A sixth aspect of the present invention is characterized in that, in the process, the aromatization catalyst is present in the aromatization reactor in the form of a fixed bed of a particulate catalyst, preferably a zeolite catalyst, most preferably a zeolite catalyst of the ZSM-5 structure type. This type of aromatization catalyst has been tried and tested and is commercially available.

[0037] A seventh aspect of the present invention is characterized in that, in the process, the aromatization catalyst used is an OTO catalyst. In this way, technical and logistic advantages are obtained, since, for example, the storage of fresh or spent catalyst is simplified.

[0038] The eighth aspect of the present invention is characterized in that, in the method, the aromatization catalyst used is a batch of OTO catalysts that have been previously used in an OTO reactor. Studies have shown that the catalyst that has been used in an OTO reactor still has sufficient activity as an aromatization catalyst. Therefore, resources are saved and economic benefits are obtained.

[0039] The ninth aspect of the present invention is characterized in that, in the method, the aromatization catalyst used is a batch of OTO catalyst that has been previously used in an OTO reactor in the process of several cycles with intermediate regeneration. Here, resource conservation and economic benefits are again enhanced.

[0040] An eleventh aspect of the invention is characterized in that the device further comprises means capable of introducing at least a portion of the gaseous substance stream G2 into the compressor. The advantages associated with this aspect correspond to those explained in connection with the second aspect of the invention.

[0041] The twelfth aspect of the invention is characterized in that the device further comprises means capable of returning at least a portion of the depentanizer overhead product stream to the compressor and introducing it into the compressor. The advantages associated with this aspect correspond to the advantages explained in connection with the third aspect of the invention.

[0042] The thirteenth aspect of the present invention is characterized in that, in the device, the aromatization catalyst is present in the aromatization reactor in the form of a fixed bed of a particulate catalyst, preferably a zeolite catalyst, most preferably a zeolite catalyst of the ZSM-5 structure type. The advantages associated with this aspect correspond to the advantages explained in connection with the sixth aspect of the present invention.

[0043] The fourteenth aspect of the present invention is characterized in that, in the device, the aromatization catalyst used is an OTO catalyst. The advantages associated with this aspect correspond to the advantages explained in connection with the seventh aspect of the present invention.

[0044] The fifteenth aspect of the present invention is characterized in that, in the apparatus, the aromatization catalyst used is a batch of OTO catalyst that has been previously used in an OTO reactor. The advantages associated with this aspect correspond to the advantages explained in connection with the eighth aspect of the present invention.

[0045] The sixteenth aspect of the present invention is characterized in that, in the device, the aromatization catalyst used is a batch of OTO catalyst that has been previously used in an OTO reactor during several cycles with intermediate regeneration. The advantages associated with this aspect correspond to the advantages explained in connection with the ninth aspect of the present invention. DETAILED DESCRIPTION

[0046] Further features, advantages and possible applications of the invention are apparent from the following description of operating and numerical embodiments and from the accompanying drawings. All features described and / or depicted, alone or in any combination, constitute the subject matter of the invention, whether they are combined in the claims or they are dependent references. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 Schematic diagram of a method / device according to the prior art,

[0048] Figure 2 Schematic diagram of the method / apparatus according to the invention.

[0049] "Not shown" hereinafter means that an element in the figure in question is not represented graphically, but is still present according to the description.

[0050] Figure 1 A schematic diagram showing an MTP process and an MTP apparatus for producing ethylene and propylene according to the prior art.

[0051] The OTO reactor 100, in which the formation of olefins is carried out from oxygenates, such as methanol and / or dimethyl ether (DME), is loaded with oxygenates and water vapor as a diluent via a fresh feed conduit (not shown); in addition, a recycle stream is also sent back to the reactor via conduits 103 and 131. Via conduit 111, the product stream from the reactor 100 is introduced into a quench system 110. The essentially aqueous phase is removed from the quench system 110 via conduit 114 and introduced into a methanol recovery unit 130. The gas phase removed in the quench system 110 enters a compressor 120 via conduit 112. Via conduit 113, a liquid phase consisting essentially of hydrocarbons is additionally fed from the quench system 110 to a compressor 120.

[0052] From the compressor 120, the liquid stream is conducted via conduit 121 to a separation device 140. In this separation device 140, the C3-fraction is separated from the C4 fraction, which is why it is also called a depropanizer. The separation device 140 is preferably configured as a separation column. The rectification in the separation device 140 is preferably carried out as an extractive distillation, so that, if desired, it is possible to supply an extractant, for example methanol, via conduit 147.

[0053] The top product drawn off at the top of the column, which contains the C3 fraction, is fed via conduit 142 to a dryer 145, from which it continues via conduit 146 to a further separation device 150. A direct connection of separation device 140 to separation device 150 is also possible. In such a separation device 150, the C3 fraction is separated from the C2 fraction, which is why separation device 150 is also referred to as a deethanizer.

[0054] Via conduit 151, the top product from separation device 150 enters separation device 160, preferably in the form of a scrubber. When it is in the form of a scrubber, a scrubbing agent, for example scrubbing water, is introduced via conduit 161 and is discharged again via conduit 162. A C2-stream present is taken off the top via conduit 163 and can be sent via conduit 164 to a recycle stream in conduit 103 which is returned to reactor 100 and / or is discharged from the system via conduit 165 and sent to a further separation device (not shown) to purify the product present, in order to obtain, for example, ethylene present as pure product.

[0055] The bottom product from separation device 150 is fed via conduit 152 to separation device 153, which separates propane from propene. In this so-called C3 splitter, propane is discharged from the system via conduit 154, and this can be used, for example, as fuel gas. The propene target product is discharged via conduit 155, and, depending on the quality requirements, this can optionally be sent to a further purification device 156 and then discharged from it via conduit 157. Purification device 156 can be filled, for example, with an adsorbent selected for oxygenates, so that oxygenates can be removed from the propene product stream down to small traces according to the specifications.

[0056] The liquid phase is discharged from the compressor via conduit 122 and sent to a separation device 170, in which the C4- fraction and the oxygenates are separated from the C4+ fraction. Such a separation device 170 is also known as a debutanizer. Via conduit 171, the C4- fraction and the overhead product containing oxygenates from the separation device 170 enter the separation device 140.

[0057] Via conduit 172, the bottom product from separation unit 170 is introduced into a further separation unit 173, in which the C7+ fraction is separated from the C6 fraction, which is why separation unit 173 is also referred to as a dehexanizer. The bottom product is discharged via conduits 174, 175. Via conduits 176, 177 and 178, a recycle stream can be sent to conduit 101, which returns to reactor 100 via conduits 102 and 103.

[0058] Furthermore, a conduit 179 can branch off from conduit 176 and lead to a separation device 180 (gasoline stabilizer). The gasoline obtained here is discharged as a valuable product via conduit 181 and conduit 175. The C4 hydrocarbons removed overhead are fed via conduit 182 to conduits 177 and 178, so that they are ultimately passed into the recycle stream in conduits 102, 103.

[0059] The bottom product from the separation device 140 is discharged via conduit 148 and thus enters a mixer-settler combination 190. Hydrocarbons are discharged therefrom via conduit 191 and can be sent back to the reactor 100 in whole or in part via conduits 101, 102, 103. Alternatively or additionally, it is possible to send the hydrocarbons via conduit 192 to a separation device 193 which is preferably configured for extraction. The top product from the separation device 193 is discharged as fuel gas via conduit 194.

[0060] From the methanol-dimethyl ether recovery 130, the oxygenate recycle stream is firstly fed back to the reactor 100 via conduit 131. Via conduits 132 and 133, it is optionally possible to feed water loaded with methanol and / or dimethyl ether into a mixer-settler unit 190 and from there also via conduit 195 it can be fed back to conduits 197 and 196.

[0061] If the separation device 193 is configured for extraction, water can be introduced into the separation device 193 as an extractant via conduits 132, 134 and can then also be fed from there back via conduit 197 to conduit 196. The water can finally be discharged from the system via conduit 135.

[0062] according to Figure 2 According to the invention, the dehexanizer bottom product stream ("MTP gasoline") discharged via conduit 175 is fed to an aromatization reactor 200 after preheating and / or evaporation (not shown) and converted therein under aromatization conditions into an aromatization reactor product stream enriched in aromatics, in particular enriched in BTX aromatics. In one example, the aromatization conditions comprise a reactor temperature between 380 and 510°C, a reactor pressure between 1 and 6 bar and the presence of a solid aromatization catalyst. In one example, the aromatization catalyst is present in the aromatization reactor in the form of a fixed bed of a particulate catalyst, preferably a zeolite catalyst, most preferably a zeolite catalyst of the ZSM-5 structure type. In one example, the aromatization catalyst used is an OTO catalyst. In one example, the aromatization catalyst used is a batch of OTO catalyst that has been previously used in an OTO reactor. In one example, the aromatization catalyst used is a batch of OTO catalyst that has been previously used in an OTO reactor during several cycles with intermediate regeneration.

[0063] The gaseous aromatization reactor product stream discharged from the aromatization reactor is cooled and partially condensed (both not shown), and then introduced into the phase separation device 220 via the conduit 210. A gaseous material stream G2 is discharged therefrom, which is discharged via the conduit 224. In one example, the gaseous material stream G2 is at least partially sent back to the compressor 120 via the conduit 224. In addition, the liquid material stream A is discharged from the phase separation device 220 via the conduit 222 and introduced into the depentanizer 230.

[0064] A depentanizer overhead product stream comprising C5- hydrocarbons is discharged from the depentanizer 230 via conduit 234. In one example, the depentanizer overhead product stream is at least partially sent back to the compressor 120 via conduit 234. In addition, a depentanizer bottom product stream comprising C6+ hydrocarbons is discharged from the depentanizer 230 via conduit 232 and is at least partially introduced into an aromatic separation unit 240 operated by at least one thermal separation method.

[0065] In the aromatics separation unit 240, the depentanizer bottoms stream is separated into a first product stream containing non-aromatic hydrocarbons and discharged from the method or device via conduit 244, and a second product stream containing BTX aromatics and discharged from the method or device as a BTX aromatics product stream via conduit 242. In one example, the aromatics separation unit 240 comprises at least two thermal separation methods. In one example, the at least two thermal separation methods comprise distillation, rectification, extractive distillation, extraction. The selection and use of these thermal separation methods and the selection of suitable operating parameters are known per se to those skilled in the art and / or can be determined by them without difficulty through routine experiments.

[0066] Numerical Example

[0067] A 540 tpd MTP gasoline stream was worked up according to the invention. The results obtained are compiled in the table below.

[0068] Table 1: Composition of MTP gasoline (comparison)

[0069]

[0070] Table 2: Composition of MTP gasoline after post-treatment according to the present invention

[0071]

[0072] Table 3: Composition of MTP gasoline (comparison): olefins

[0073] contrast Ethylene Propylene Butene tpd (gasoline) 0 0 2.7

[0074] Table 4: Composition of MTP gasoline after post-treatment according to the present invention: Olefins

[0075] The present invention Ethylene Propylene Butene tpd (gasoline) 5.8 11.4 4.8

[0076] Table 5: Composition of MTP gasoline (comparison): BTX aromatics

[0077]

[0078]

[0079] Table 6: Composition of MTP gasoline after post-treatment according to the present invention: BTX aromatics

[0080] The present invention benzene Toluene Xylene tpd (gasoline) 11.6 57.4 108.3

[0081] From the data compiled in the table it can be clearly seen that the post-treatment of MTP gasoline according to the invention results in:

[0082] - The content and amount of aromatics increased significantly,

[0083] - The content of olefins (especially longer chain olefins) and cycloalkanes (cycloalkanes) in MTP gasoline is reduced,

[0084] - Increased content and production of short-chain olefins, especially ethylene and propylene,

[0085] -BTX aromatics content and product amount increased significantly.

[0086] List of Reference Symbols

[0087] 100 OTO reactor

[0088] 101-103 catheter

[0089] 110 quenching system

[0090] 111-114 catheter

[0091] 120 compressor

[0092] 121-123 catheter

[0093] 130 Methanol-DME Recovery

[0094] 131-135 catheter

[0095] 140 Separation device

[0096] 142 catheter

[0097] 150 Separation device

[0098] 151, 152 catheter

[0099] 153 Separation device

[0100] 154, 155 catheter

[0101] 156 Purification stage

[0102] 157 Catheter

[0103] 160 Separation device

[0104] 161-165 Catheter

[0105] 170 Separation device

[0106] 171, 172 catheter

[0107] 173 Separation device

[0108] 174-179 Catheter

[0109] 180 Separation device (gasoline stabilization tower)

[0110] 181, 182 catheter

[0111] 190 Mixer-settler combination

[0112] 191,192 Catheter

[0113] 193 Separation device

[0114] 194-197 Catheter

[0115] 200 Aromatization Reactor

[0116] 210 Catheter

[0117] 220 Phase separation device

[0118] 222 Catheter

[0119] 224 Catheter

[0120] 230 Depentanizer

[0121] 232 Catheter

[0122] 234 Catheter

[0123] 240 Aromatic Separation Unit

[0124] 242 Catheter

[0125] 244 Catheter

Claims

1. A method for preparing ethylene, propylene and BTX aromatics from oxygen-containing compounds, comprising the following steps: (a) providing a feed stream containing an oxygenate and converting the oxygenate in the feed stream into a reactor product stream containing water, hydrocarbons and at least one oxygenate in an oxygenate-to-olefins reactor (OTO reactor) over an oxygenate-to-olefins catalyst (OTO catalyst) under heterogeneous catalysis under oxygenate conversion conditions; (b) quenching the reactor product stream in at least one quenching stage and compressing the quenched reactor product stream in a compressor downstream of the quenching stage, wherein the quenching and / or compression of the reactor product stream provides the following material streams: (b1) a gaseous substance stream G1 comprising hydrocarbons and in particular olefins, (b2) a liquid substance stream W comprising water and oxygen-containing compounds, (b3) a liquid substance stream O comprising hydrocarbons and in particular olefins; (c) performing multi-stage separation of the material stream G1 by a thermal separation method to obtain a set of product streams, wherein the set of product streams comprises: (c1) an ethylene product stream comprising ethylene, which is at least partly discharged from the process, (c2) a propylene product stream comprising propylene, which is discharged from the process; (d) a multistage separation of the substance stream O by a thermal separation process, wherein (d1) feeding the material stream O to a debutanizer and separating it therein into a debutanizer overhead product stream and a debutanizer bottom product stream, wherein the debutanizer overhead product stream comprises C4- hydrocarbons and oxygenates, and wherein the debutanizer bottom product stream comprises C4+ hydrocarbons, (d2) sending the debutanizer top product stream to step (c), (d3) introducing the debutanizer bottoms stream into a dehexanizer; (e) separating the debutanizer bottoms stream in a dehexanizer into a dehexanizer overhead stream comprising C6- hydrocarbons and a dehexanizer bottoms stream comprising C7+ hydrocarbons; (f) recycling at least a portion, preferably all, of the dehexanizer overhead product stream to the OTO reactor; (g) vaporizing at least a portion of the dehexanizer bottoms stream and introducing the vaporized dehexanizer bottoms stream into an aromatization reactor in a fixed bed configuration, converting the vaporized dehexanizer bottoms stream in the aromatization reactor under aromatization conditions, and discharging a gaseous aromatization reactor product stream from the aromatization reactor; (h) cooling and partially condensing the gaseous aromatization reactor product stream and introducing the cooled aromatization reactor product stream into a phase separation device, from which a gaseous material stream G2 and a liquid material stream A are discharged; (i) feeding at least a portion of the liquid material stream A to a depentanizer operated by a thermal separation process, wherein the liquid material stream A is separated in the depentanizer into a depentanizer overhead product stream comprising C5- hydrocarbons and a depentanizer bottom product stream comprising C6+ hydrocarbons; (j) supplying at least a portion of the depentanizer bottoms stream to an aromatics separation unit operated by at least one thermal separation process, wherein the depentanizer bottoms stream is separated in the aromatics separation unit into a first product stream containing non-aromatic hydrocarbons and a second product stream containing BTX aromatics, which is discharged from the process as a BTX aromatics product stream.

2. The method according to claim 1, characterized in that At least part of the gaseous substance stream G2 is introduced into a compressor.

3. The method according to claim 1 or 2, characterized in that At least a portion of the depentanizer overhead product stream is returned and introduced into a compressor.

4. A method according to any one of the preceding claims, characterised in that The portion of the depentanizer overhead product stream that is returned to the compressor is mixed with the reactor product stream prior to introduction into the compressor.

5. A method according to any one of the preceding claims, characterised in that The aromatization conditions comprise a reactor temperature between 380 and 510° C., a reactor pressure between 1 and 6 bar, and the presence of a solid aromatization catalyst.

6. The method according to claim 5, characterized in that The aromatization catalyst is present in the aromatization reactor in the form of a fixed bed of a particulate catalyst, preferably a zeolite catalyst, most preferably a zeolite catalyst of the ZSM-5 structure type.

7. The method according to claim 6, characterized in that The aromatization catalyst used was an OTO catalyst.

8. The method according to claim 7, characterized in that The aromatization catalyst used was a batch of OTO catalyst that had been previously used in an OTO reactor.

9. The method according to claim 8, characterized in that The aromatization catalyst used was a batch of OTO catalyst which had been previously used in an OTO reactor in the course of several cycles with intermediate regenerations.

10. An apparatus for preparing ethylene, propylene and BTX aromatics from oxygenates, comprising the following assemblies and components fluidly connected to each other: (a) an oxygenate-to-olefins reactor (OTO reactor) having an oxygenate-to-olefins catalyst (OTO catalyst), means for providing a feed stream containing an oxygenate and means for introducing it into the OTO reactor, and means for withdrawing a reactor product stream containing water, hydrocarbons and at least one oxygenate from the OTO reactor; (b) a quenching stage and a compressor downstream of the quenching stage, configured to quench the reactor product stream in the quenching stage and to compress the quenched reactor product stream in the compressor, means for discharging from the quenching stage and / or from the compressor a stream of: (b1) a gaseous substance stream G1 comprising hydrocarbons and in particular olefins, (b2) a liquid substance stream W comprising water and oxygen-containing compounds, (b3) a liquid substance stream O comprising hydrocarbons and in particular olefins; (c) a first multistage separation device for separating the substance stream G1 by a thermal separation process, a device for discharging a set of product streams from the multistage separation device, wherein the set of product streams comprises: (c1) an ethylene product stream comprising ethylene, at least part of which is discharged from the process, another part of which is recycled to the OTO reactor, (c2) a propylene product stream comprising propylene, which is discharged from the process; (d) a second multi-stage separation device for separating the material stream O by a thermal separation method, further comprising a device capable of: (d1) feeding the material stream O to a debutanizer and separating it therein into a debutanizer overhead product stream and a debutanizer bottom product stream, wherein the debutanizer overhead product stream comprises C4- hydrocarbons and oxygenates, and wherein the debutanizer bottom product stream comprises C4+ hydrocarbons, (d2) sending the debutanizer top product stream to step (c), (d3) introducing the debutanizer bottoms stream into a dehexanizer; (e) a device for separating the debutanizer bottoms stream in a dehexanizer into a dehexanizer overhead stream comprising C6- hydrocarbons and a dehexanizer bottoms stream comprising C7+ hydrocarbons; (f) a device for recycling at least a portion, preferably all, of the dehexanizer overhead product stream to the OTO reactor; (g) means for evaporating at least a portion of said dehexanizer bottoms stream, and means for introducing said evaporated dehexanizer bottoms stream into an aromatization reactor in a fixed bed configuration, and means for removing a gaseous aromatization reactor product stream from said aromatization reactor; (h) a phase separation device, a device for cooling the gaseous aromatization reactor product stream and a device for introducing the cooled aromatization reactor product stream into the phase separation device, and a device for withdrawing a gaseous material stream G2 and a liquid material stream A from the phase separation device; (i) a depentanizer operated by a thermal separation process, means for feeding at least a portion of the liquid material stream A to the depentanizer, means for removing a depentanizer overhead product stream comprising C5- hydrocarbons from the depentanizer, and means for removing a depentanizer bottom product stream comprising C6+ hydrocarbons from the depentanizer; (j) an aromatics separation unit operated by at least one thermal separation process, a unit for feeding at least a portion of the depentanizer bottom product stream to the aromatics separation unit, a unit for discharging a first product stream containing non-aromatic hydrocarbons from the aromatics separation unit and a unit for discharging a second product stream containing BTX aromatics from the aromatics separation unit, and a unit for discharging the second product stream from the aromatics separation unit as a BTX aromatics product stream from the unit.

11. The device according to claim 10, characterized in that It further comprises means capable of introducing at least a portion of the gaseous substance stream G2 into the compressor.

12. The device according to claim 10 or 11, characterized in that It further comprises means capable of returning at least a portion of the depentanizer overhead product stream to the compressor and introducing it into said compressor.

13. The device according to any one of claims 10 to 12, characterized in that The aromatization catalyst is present in the aromatization reactor in the form of a fixed bed of a particulate catalyst, preferably a zeolite catalyst, most preferably a zeolite catalyst of the ZSM-5 structure type.

14. The device according to any one of claims 10 to 13, characterized in that The aromatization catalyst used was an OTO catalyst.

15. The device according to any one of claims 10 to 14, characterized in that The aromatization catalyst used was a batch of OTO catalyst that had been previously used in an OTO reactor.

16. The device according to any one of claims 10 to 15, characterized in that The aromatization catalyst used was a batch of OTO catalyst which had been previously used in an OTO reactor in the course of several cycles with intermediate regenerations.

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