Process for preparing C2-C4 olefins from methanol and ethanol

Abstract

The invention relates to a process for producing C2-C4 olefins from methanol and ethanol, having the following steps: A) feeding a methanol-and optionally ethanol-containing feed stream A into a dimethyl ether fixed bed reactor and catalytically reacting methanol to form dimethyl ether, in which a product stream A1 containing dimethyl ether, methanol, ethanol and steam is obtained; b) mixing stream A1 with at least one hydrocarbon return stream R containing C2-C6 hydrocarbons and catalytically reacting the mixture in an olefin fixed bed reactor to form a crude product stream B containing C2-C4 olefins, C5-C6 hydrocarbons and C7 + hydrocarbons; c) cooling the crude product stream B, wherein a hydrocarbon crude product stream C is obtained; d) separating the hydrocarbon crude product stream C into a value product stream comprising propylene, optionally ethylene, a value product stream comprising butene, at least one return stream comprising C5-C6 hydrocarbons and at least one by-product stream comprising C6 + hydrocarbons; e) returning a portion of the C2-C4 olefins and at least a portion of the C5-C6 hydrocarbons to step B) as one or more hydrocarbon return streams; f) recovering a value product stream comprising propylene, a value product stream comprising ethylene and optionally a value product stream comprising butene; g) discharging a by-product stream containing C6 + hydrocarbons; characterized in that stream A contains lt with respect to methanol and ethanol; wherein, relative to 100 wt.% of the C2-C4 olefins recovered as valuable products, 30 wt.% to 60 wt.% of ethylene, 30 wt.% to 60 wt.% of propylene and 0 wt.% to 30 wt.% of butene are recovered as valuable products, and 0% to 40% of ethylene, 40% to 90% of propylene and 0% to 100% of butene are fed back to step B) relative to the C2-C4 olefins contained in the crude product stream B, the stream A contains 1 wt.% to 30 wt.% of ethanol relative to methanol and ethanol, where 0 wt.% to 20 wt.% of ethylene, 70 wt.% to 100 wt.% of propylene and 1 wt.% to 20 wt.% of butene are recovered as valuable products relative to 100 wt.% of C2-C4 olefins recovered as valuable products, and where 0 wt.% to 20 wt.% of propylene and 1 wt.% to 20 wt.% of butene are recovered relative to 100 wt.% of C2-C4 olefins contained in the crude product stream B. And feeding 0%-100% of ethylene, 0%-20% of propylene and 40%-100% of butene back to the step B).

Description

[0001] The present invention relates to a process for preparing C2-C4 olefins from methanol with or without ethanol.

[0002] It is known that propylene can be produced by converting a methanol / dimethyl ether mixture in a fixed bed reactor (methanol to propylene, MTP reactor).The known fixed bed reactor operates with a zeolite catalyst at a temperature of about 480°C.

[0003] US2010 / 145125 A1 discloses a method for preparing light olefins by converting methanol and ethanol. The method comprises feeding a first portion of feed to a reaction zone containing a catalyst via a distributor at the bottom of a fluidized bed reactor, feeding a second portion of feed to the reaction zone from at least one position above the distributor, contacting the feed with the catalyst and reacting to produce a stream containing ethylene and propylene, wherein the first and second portions of feed each independently contain methanol and / or ethanol, provided that the entire feed contains both methanol and ethanol, and the weight ratio of methanol to ethanol in the entire feed is in the range of 99:1 to 0.1:1.

[0004] CN 216106699 U discloses a method for preparing ethylene, propylene and butene by catalytic dehydration of methanol. The system comprises a reaction unit and a separation unit, wherein the reaction unit comprises a preliminary reactor, a process steam tower and a main reactor, and the separation unit comprises a quencher and a compressor. The main reactor contains a ZSM-5 molecular sieve catalyst; the separation unit comprises an ethylene tower, a propylene tower and a butene tower. Ethane, propane, butane, and C5 and C6 hydrocarbons are partially recycled to the main reactor; other components are discharged as by-products. Butene can also be prepared using the unit while reducing the amount of recycled hydrocarbons and reducing the energy consumption of the unit. Only saturated hydrocarbons are recycled to the main reactor.

[0005] CN 110218138 A discloses a method for increasing the olefin yield in a methanol to propylene process (MTP process), wherein C2 hydrocarbons, C4 hydrocarbons and C5-C7 hydrocarbons are recycled to the MTP reactor. In one example, in a 500 000 t / a methanol to propylene plant, the methanol feed is 210 t / h, and the recycled feeds of C2, C4 and C5-C7 hydrocarbons are 27 t / h, 40 t / h and 150 t / h, respectively. The ethylene production is 1.5 t / h; the propylene production is 60 t / h. There is no mention of the co-feeding of ethanol. The valuable product obtained is very mainly propylene.

[0006] The object of the present invention is to provide a flexible process for preparing C2-C4 olefins from methanol in a methanol to olefins process (MTO process), in which the proportions of ethylene, propylene and butenes in the valuable product stream obtained from the process can be varied within wide ranges and the volumes of recycle streams which are recycled into the MTO process can be reduced overall.

[0007] This object is achieved by a process for preparing C2-C4 olefins from methanol with or without ethanol, the process comprising the following steps:

[0008] A) feeding a feed stream A comprising methanol with or without ethanol into a dimethyl ether fixed bed reactor and catalytically converting the methanol into dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol and water vapor with or without ethanol and ethylene;

[0009] B) mixing stream A1 with at least one hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and catalytically converting it in an olefin fixed bed reactor into a hydrocarbon stream comprising C2-C4 olefins, C5-C6 hydrocarbons and C7 + a crude hydrocarbon product stream B;

[0010] C) cooling the crude product stream B to obtain a hydrocarbon crude product stream C;

[0011] D) separating the crude hydrocarbon stream C into a product stream of value comprising propene, optionally a product stream of value comprising ethylene, a product stream of value comprising butenes, at least one recycle stream comprising C5-C6 hydrocarbons, and at least one recycle stream comprising C6 + hydrocarbon byproduct streams;

[0012] E) recycling a portion of the C2-C4 olefins and at least a portion of the C5-C6 hydrocarbons as one or more hydrocarbon recycle streams R to step B);

[0013] F) obtaining a product stream of value comprising propene, a product stream of value comprising ethylene, and optionally a product stream of value comprising butenes;

[0014] G) Excretion of C6 + hydrocarbon byproduct streams;

[0015] wherein stream A comprises <1% by weight or 30% to 50% by weight of ethanol, based on methanol and ethanol, wherein, based on 100% by weight of the C2-C4-olefins obtained as products of value, 30% to 60% by weight of ethylene, 30% to 60% by weight of propylene and 0% to 30% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 40% of ethylene, 40% to 90% of propylene and 0% to 100% of butenes are recycled to step B),

[0016] Alternatively, stream A comprises 1% by weight and 30% by weight of ethanol, based on methanol and ethanol, wherein, based on 100% by weight of the C2-C4-olefins obtained as products of value, 0% to 20% by weight of ethylene, 70% to 100% by weight of propylene and 1% to 20% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 100% of ethylene, 0% to 20% of propylene and 40% to 100% of butenes are recycled to step B).

[0017] In the process according to the invention, based on 100% by weight of the C2-C4 olefins obtained as products of value, 30% to 60% by weight of ethylene, 30% to 60% by weight of propylene and 0% to 30% by weight of butenes are obtained as products of value, and, based on the C2-C4 olefins present in the crude product stream B, 0% to 40% of ethylene, 40% to 90% of propylene and 0% to 100% of butenes can be recycled to step B). The proportion of ethanol in the total amount of alcohol (ethanol and methanol) fed to the process can be <1% by weight, in particular 0% by weight. Alternatively, the process economy can be improved when the proportion of ethanol in the alcohol fed to the process is 30% to 50% by weight.

[0018] Alternatively, the proportion of ethanol in the alcohol fed to the overall process can also be between 1% and 30% by weight, in which, based on 100% by weight of the C2-C4-olefins obtained as products of value, 0% to 20% by weight of ethylene, 70% to 100% by weight of propylene and 1% to 20% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 100% of ethylene, 0% to 20% of propylene and 40% to 100% of butenes are recycled into step B).

[0019] It has been found that by means of a modified recycle variant, product compositions can be obtained which would only be possible by very complex catalyst optimization. Furthermore, the addition of ethanol within a defined preferred range ensures a significant reduction in the volume of recycle streams and by-products. This significantly reduces the energy requirement of the process, since, for example, less mass must be separated in a complex manner downstream of the reactor.

[0020] In a preferred embodiment, the method of the present invention comprises the following steps:

[0021] A1) feeding a feed stream A comprising methanol with or without ethanol into a dimethyl ether fixed bed reactor and catalytically converting the methanol into dimethyl ether and optionally catalytically converting the ethanol into ethylene to obtain a product stream A1 comprising dimethyl ether, methanol and water vapor with or without ethanol and ethylene;

[0022] A2) mixing at least a portion of the product stream A1 with at least one hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and a steam stream to obtain a second feed stream A2;

[0023] B1) heating the second feed stream A2 in one or more heat exchangers to a temperature in the range of 430° C. to 500° C. and feeding it into an olefin fixed bed reactor, wherein the heating can also be carried out before mixing the individual substreams in step A2 to obtain the feed stream A2;

[0024] B2) catalytically converting the feed stream A2 at a temperature in the range of 430° C. to 520° C. into a mixture comprising ethylene, propylene, butenes, further C2-C6 hydrocarbons, C7 + a crude product gas stream B of hydrocarbons, methanol and water vapor;

[0025] C1) cooling the crude product gas stream B to a temperature in the range of 170° C. to 220° C. in one or more heat exchangers by heat exchange with the feed stream A2;

[0026] C2) further cooling the crude product gas stream B to a temperature in the range of 30° C. to 60° C. under condensation of water and methanol by contacting with at least one aqueous quench circulation stream K to obtain a hydrocarbon crude product gas stream C depleted in water and methanol;

[0027] D) separating the crude hydrocarbon gas stream C into a product-of-value stream comprising propene, optionally a product-of-value stream comprising ethylene, a product-of-value stream comprising butenes, at least one recycle stream comprising C5-C6 hydrocarbons, and at least one recycle stream comprising C6 + A hydrocarbon by-product stream.

[0028] In step A1), a feed stream A comprising methanol and ethanol is fed into a dimethyl ether fixed bed reactor and the methanol is catalytically converted into dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor.

[0029] If, based on 100% by weight of the C2-C4 olefins obtained as valuable products, 30% to 60% by weight of ethylene, 30% to 60% by weight of propylene and 0% to 30% by weight of butenes are obtained as valuable products, the proportion of ethanol in the total amount of alcohols (ethanol and methanol) fed to the process can be <1% by weight. Alternatively, the proportion of ethanol can be increased to 30% to 50% by weight in order to obtain a more favorable operating window.

[0030] Alternatively, when, based on 100% by weight of the C2-C4-olefins obtained as valuable products, 1 to 20% by weight of ethylene, 70 to 100% by weight of propylene and 0 to 20% by weight of butenes are obtained as valuable products, an advantageous proportion of ethanol in the total amount of alcohols (ethanol and methanol) fed to the process is 1 to 30% by weight.

[0031] The dimethyl ether fixed bed reactor can be designed in various ways, depending on the exact composition of the feed gas stream. Typically, a feed gas stream A comprising methanol with or without ethanol is heated to a temperature above 250° C. and fed into a fixed bed reactor. The catalyst used is typically gamma-alumina. The conversion temperature is between 250° C. and 450° C., and the pressure is between 1 bar and 25 bar, for example 4 bar. The methanol conversion is typically 50% to 90%, preferably 65% ​​to 85%, for example 75%.

[0032] In the case of a small proportion of ethanol, stream A can be preheated to a temperature of 250° C. to 300° C., for example 275° C. The product gas stream A1 leaving the reactor is then at a temperature of typically 350° C. to 400° C., for example 370° C. This stream is then cooled by heat exchange with stream A to a temperature of typically 180° C. to 250° C.

[0033] In the case of a relatively high ethanol content in stream A, stream A can alternatively also be heated to a temperature of up to 450° C. and the reactor operated adiabatically. Alternatively, the reactor can be designed as a heated reactor, in which case stream A must only be heated to a temperature of up to 400° C.

[0034] In step A2), at least a portion of the stream A1 is mixed with a hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and a water vapor stream to obtain a feed gas stream A2. Typically, this portion of stream A1 is at least 50% by weight and preferably up to 90% by weight. Another portion A1-2 of stream A1, preferably at least 10% by weight, can be fed directly into one or more trays of an olefin fixed bed reactor. This portion of stream A1 is typically cooled before being fed into the trays of the olefin fixed bed reactor, preferably cooled to a temperature in the range of 30°C to 60°C. This substream A1-2 is preferably fed into the reactor in liquid form.

[0035] If the olefin fixed bed reactor is operated and cooled isothermally, the cooling of substream A1-2 can also be omitted. Isothermal operation can be achieved, for example, in the manner described in WO 2017 / 102096 A1. For example, a heat transfer surface operated, for example, with liquid salt or high-pressure steam as a heat transfer medium can be installed in the olefin fixed bed reactor. Since the heat transfer medium flows through the heat transfer surface in the reactor, the generated reaction heat is removed from the reactor and the reactor is therefore operated isothermally. In order to establish the desired product distribution in the product gas stream B, substream A1-2 can also be fed to the intermediate stage of the olefin fixed bed reactor.

[0036] The at least one hydrocarbon recycle stream R from the removal of C2-C4 olefins generally comprises C1-C6 hydrocarbons. Depending on the ratio in which ethylene, propylene and butene are obtained as valuable products in step E), the at least one hydrocarbon recycle stream comprises C2-C4 hydrocarbons, generally in an amount of a total of 50% by weight to 90% by weight. Prior to mixing, the at least one hydrocarbon recycle stream is generally at a temperature in the range of 100° C. to 175° C., preferably in the range of 130° C. to 160° C.

[0037] The product stream A1 from the dimethyl ether fixed bed reactor is also mixed with a steam stream. The steam stream is generally at a temperature in the range of 100° C. to 200° C., preferably in the range of 100° C. to 150° C. The feed stream A2 thus obtained generally comprises 20% to 70% by weight, preferably 30% to 60% by weight, of steam. It generally further comprises 5% to 10% by weight of methanol, 0% to 15% by weight of ethanol, 10% to 20% by weight of dimethyl ether and 15% to 50% by weight of C2-C6 hydrocarbons.

[0038] In step B1), feed stream A2 is heated in one or more heat exchangers to a temperature generally in the range of 430° C. to 500° C. and fed to an olefin fixed bed reactor. This heating can also be carried out before mixing the individual substreams in step A2).

[0039] Typically, the feed stream A2 is at a temperature in the range of 430° C. to 500° C., for example 470° C. when fed to the olefin fixed bed reactor. The feed stream A2 can be heated to this temperature by heat exchange with the crude product gas stream B from the olefin fixed bed reactor, direct electrical heating, or heating via combustion of a separate fossil energy carrier.

[0040] Then, in step B2), the olefins are catalytically converted into olefins containing ethylene, propylene, butene, other C2-C6 hydrocarbons, C7 +The product gas stream B of hydrocarbons, methanol and water vapor is obtained. The conversion is usually carried out on a zeolite catalyst, preferably on a catalyst based on ZSM-5 zeolite. The reaction temperature is usually 430° C. to 500° C., preferably 460° C. to 480° C. The pressure is usually 1.3 to 2.5 bar. The resulting crude product gas stream B2 preferably has the following composition: 1% to 15% by weight of ethylene, 1% to 15% by weight of propylene, 35% to 80% by weight of water, 15% to 50% by weight of C2-C6 hydrocarbons (especially butene, and saturated C4 and C5 hydrocarbons and C6 + hydrocarbons), and also 0.01 to 1.5% by weight of methanol and dimethyl ether.

[0041] The olefin fixed bed reactor is usually in the form of a tray reactor. The number of trays is preferably 4 to 6. In one embodiment, a total of up to 50% by weight of the gas stream A is directly fed into one or more trays of the olefin fixed bed reactor, preferably all trays of the olefin fixed bed reactor. In another embodiment, methanol is directly fed into one or more trays of the olefin fixed bed reactor, preferably all trays of the olefin fixed bed reactor.

[0042] The crude product gas stream B is at a temperature of generally from 430 to 520°C, preferably from 460 to 480°C, on exiting from the reactor.

[0043] In a preferred step C1), the crude product gas stream B is cooled in one or more heat exchangers by heat exchange with the feed gas stream A2 to a temperature in the range of 170° C. to 220° C. After this cooling step, the temperature of the crude product gas stream B is typically 160° C. to 220° C., preferably 170° C. to 210° C., for example 190° C.

[0044] In a preferred step C2), the crude product gas stream B is further cooled to a temperature in the range of 30°C to 60°C by contacting with one or more aqueous quench circulation streams under condensation of water and methanol to obtain a water-depleted and methanol-depleted hydrocarbon crude product gas stream C. The hydrocarbon crude product gas stream C thus obtained substantially comprises ethylene, propylene, additional C2-C6 hydrocarbons and C7 + hydrocarbon.

[0045] In step D), one or more product streams comprising C2-C4 olefins are separated from the hydrocarbon crude product gas stream C, and at least one recycle stream R comprising C2-C6 hydrocarbons is obtained. The (entire) recycle stream R may comprise or be formed from a plurality of individual recycle streams R1, R2, R3, etc. Typically, the entire recycle stream R comprising C2-C6 hydrocarbons comprises essentially, i.e. to an extent of >95% by weight, C2-C6 hydrocarbons.

[0046] Typically, step D) comprises steps D1) to D7):

[0047] D1) compressing the hydrocarbon crude product gas stream C to obtain a product comprising propylene and C4, C5 and C6 + a liquid hydrocarbon stream D11 of hydrocarbons and a gaseous hydrocarbon stream D12 comprising ethane, ethylene and propylene;

[0048] D2) separating water from the liquid hydrocarbon stream D11 by phase separation to obtain a liquid hydrocarbon stream D21;

[0049] D3) separating a stream D31 comprising propylene from the liquid hydrocarbon stream D21 to obtain a stream D31 comprising C4, C5 and C6 + or separating a stream D31 comprising propylene and C4 hydrocarbons to obtain a stream D32 comprising C4, C5 and C6 + a stream D32 of hydrocarbons;

[0050] D4) from the containing C4, C5 and C6 + The hydrocarbon stream D32 is separated into C6 + a byproduct stream D41 of hydrocarbons to obtain a stream D42 comprising C4, C5 and C6 hydrocarbons; stream D41 optionally comprises aromatic C6 hydrocarbons, and stream D42 optionally comprises aliphatic C6 hydrocarbons;

[0051] D5) separating a stream D51 comprising propylene from the gaseous hydrocarbon stream D12 comprising ethane, ethylene and propylene to obtain a stream D52 comprising ethane and ethylene;

[0052] D6) separating a stream D61 comprising butenes from the stream D42 comprising C4, C5 and C6 hydrocarbons to obtain a stream D62 comprising C5 and C6 hydrocarbons; and or separating a stream D63 comprising propylene from the stream D31 to obtain a stream D64 comprising butenes;

[0053] D7) obtaining at least one recycle stream R from one or more streams selected from the group consisting of: a stream D42 comprising C4, C5 and C6 hydrocarbons, a stream D62 comprising C5 and C6 hydrocarbons, a stream D31 comprising propylene, a stream D51 comprising propylene, a stream D63 comprising propylene, a stream D61 comprising butenes, a stream D64 comprising butenes, and a stream D52 comprising ethane and ethylene.

[0054] Steps D3), D4), D5) and D6) are carried out in standard distillation apparatuses. Usable distillation apparatuses include in principle the apparatuses known to the person skilled in the art for such separation tasks. In addition to the actual column body with internals, the distillation column generally also comprises a top condenser and a reboiler. The column body may already be equipped with, for example, structured packing, random packing or trays. The distillation apparatus can be designed and operated by the common general knowledge of the person skilled in the art.

[0055] In step E), a portion of the C2-C4 olefins and at least a portion of the C5-C6 hydrocarbons are recycled as one or more hydrocarbon recycle streams R into step B).

[0056] In step F), a product stream of value comprising propene, a product stream of value comprising ethylene and optionally a product stream of value comprising butenes are obtained.

[0057] Propylene can be obtained as a valuable product from stream D31 or D63 and D51. Ethylene can be obtained as a valuable product from stream D52. Butenes can be obtained from stream D61 and / or D64.

[0058] One or more recycle streams R may be obtained from one or more of the above-mentioned streams D31 , D42, D51 , D52, D61 , D62, D63 and D64.

[0059] Based on 100% by weight of the C2-C4-olefins obtained as products of value, 30% to 60% by weight of ethylene, 30% to 60% by weight of propylene and 0% to 30% by weight of butenes are obtained as products of value, and based on the C2-C4-olefins present in the crude product stream B, 0% to 40% by weight of ethylene, 40% to 90% by weight of propylene and 0% to 100% by weight of butenes are recycled to step B), or, based on 100% by weight of the C2-C4-olefins obtained as products of value, 0% to 20% by weight of ethylene, 70% to 100% by weight of propylene and 1% to 20% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 100% by weight of ethylene, 0% to 20% by weight of propylene and 40% to 100% of butenes are recycled to step B).

[0060] In step G), the C6 + A hydrocarbon by-product stream. This may be stream D41.

[0061] The present invention is explained in detail by the following examples.

[0062] Examples

[0063] The following ranges 1-4 of the composition of the feed stream (ethanol content), the composition of the crude product stream (ratios of C2 / C3 olefins and C4 / C3 olefins) and the composition of the resulting valuable products (proportions of C2, C3 and C4 olefins) were simulated by calculation. The numbers are weight ratios.

[0064] In order to determine the preferred ranges, catalytic experiments were performed on a laboratory scale, based on which the expected conversion and mass flow rates in an industrial process with a preliminary reactor, a tray reactor and a separation section were calculated. The optimization of this system resulted in the ranges 1-4 specified in Table 1. Table 2 shows the relevant flow rates for the example points determined in ranges 1 and 2. Similar example values ​​for ranges 3 and 4 are listed in Table 3. The addition of ethanol in each case allows minimization of the relative recycle stream (recycle) and the relative by-product stream, and therefore allows improvement of the energy efficiency and mass efficiency of the process.

[0065] Table 1

[0066]

[0067] The results of the simulation are collated in Tables 2 and 3. All figures are given by weight.

[0068] Table 2

[0069]

[0070]

[0071] Table 3

[0072]

Claims

1. A method for preparing C2-C4 olefins from methanol and ethanol, the method comprising the following steps: A) feeding a feed stream A comprising methanol with or without ethanol into a dimethyl ether fixed bed reactor and catalytically converting the methanol into dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor; B) mixing stream A1 with at least one hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and catalytically converting it in an olefin fixed bed reactor into a hydrocarbon stream comprising C2-C4 olefins, C5-C6 hydrocarbons and C7 + a crude hydrocarbon product stream B; C) cooling the crude product stream B to obtain a hydrocarbon crude product stream C; D) separating the crude hydrocarbon stream C into a product stream of value comprising propene, optionally a product stream of value comprising ethylene, at least one recycle stream comprising C5-C6 hydrocarbons, and at least one recycle stream comprising C6 + hydrocarbon byproduct streams; E) recycling a portion of the C2-C4 olefins and at least a portion of the C5-C6 hydrocarbons to step B) as one or more hydrocarbon recycle streams; F) obtaining a product stream of value comprising propene, a product stream of value comprising ethylene, and optionally a product stream of value comprising butenes; G) Expel the C6 + hydrocarbon byproduct streams; in stream A comprises <1% by weight or 30% to 50% by weight of ethanol, based on methanol and ethanol, wherein, based on 100% by weight of the C2-C4-olefins obtained as products of value, 30% to 60% by weight of ethylene, 30% to 60% by weight of propylene and 0% to 30% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 40% of the ethylene, 40% to 90% of the propylene and 0% to 100% of the butenes are recycled to step B), Alternatively, stream A comprises 1 to 30% by weight of ethanol, based on methanol and ethanol, wherein, based on 100% by weight of the C2-C4-olefins obtained as products of value, 0 to 20% by weight of ethylene, 70 to 100% by weight of propylene and 1 to 20% by weight of butenes are obtained as products of value, and, based on the C2-C4-olefins present in the crude product stream B, 0% to 100% of this ethylene, 0% to 20% of this propylene and 40% to 100% of this butenes are recycled into step B).

2. The method according to claim 1, wherein: Steps A) to D) include the following steps A1), A2), B1), B2), C1), C2) and D): A1) feeding a feed stream A comprising methanol and ethanol into a dimethyl ether fixed bed reactor and catalytically converting methanol into dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor; A2) mixing at least a portion of the product stream A1 with at least one hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and a steam stream to obtain a second feed stream A2; B1) heating the second feed stream A2 in one or more heat exchangers to a temperature in the range of 430° C. to 500° C. and feeding it into an olefin fixed bed reactor, wherein the heating can also be carried out before mixing the individual substreams in step A2 to obtain the feed stream A2; B2) catalytically converting the feed stream A2 at a temperature in the range of 430° C. to 520° C. into a mixture comprising ethylene, propylene, butenes, further C2-C6 hydrocarbons, C7 + a crude product gas stream B of hydrocarbons, methanol and water vapor; C1) cooling the crude product gas stream B to a temperature in the range of 170° C. to 220° C. in one or more heat exchangers by heat exchange with the feed stream A2; C2) further cooling the crude product gas stream B to a temperature in the range of 30° C. to 60° C. under condensation of water and methanol by contacting with at least one aqueous quench circulation stream K to obtain a water-depleted and methanol-depleted hydrocarbon crude product gas stream C2; D) separating the crude hydrocarbon gas stream C into a product-of-value stream comprising propene, optionally a product-of-value stream comprising ethylene, a product-of-value stream comprising butenes, at least one recycle stream comprising C5-C6 hydrocarbons, and at least one recycle stream comprising C6 + A hydrocarbon by-product stream.

3. The method according to claim 1 or 2, wherein: Step D) comprises steps D1) to D7): D1) compressing the hydrocarbon crude product gas stream C to obtain a product comprising propylene and C4, C5 and C6 + a liquid hydrocarbon stream D11 of hydrocarbons and a gaseous hydrocarbon stream D12 comprising ethane, ethylene and propylene; D2) separating water from the liquid hydrocarbon stream D11 by phase separation to obtain a liquid hydrocarbon stream D21; D3) separating a stream D31 comprising propylene from the liquid hydrocarbon stream D21 to obtain a stream D31 comprising C4, C5 and C6 + or separating a stream D31 comprising propylene and C4 hydrocarbons to obtain a stream D32 comprising C4, C5 and C6 + a stream D32 of hydrocarbons; D4) from the containing C4, C5 and C6 + The hydrocarbon stream D32 is separated into C6 + a byproduct stream D41 of hydrocarbons to obtain a stream D42 comprising C4, C5 and C6 hydrocarbons; stream D41 optionally comprises aromatic C6 hydrocarbons, and stream D42 optionally comprises aliphatic C6 hydrocarbons; D5) separating a stream D51 comprising propylene from the gaseous hydrocarbon stream D12 comprising ethane, ethylene and propylene to obtain a stream D52 comprising ethane and ethylene; D6) separating a stream D61 comprising butenes from the stream D42 comprising C4, C5 and C6 hydrocarbons to obtain a stream D62 comprising C5 and C6 hydrocarbons; and or separating a stream D63 comprising propylene from the stream D31 to obtain a stream D64 comprising butenes; D7) obtaining at least one recycle stream R from one or more streams selected from the group consisting of: a stream D42 comprising C4, C5 and C6 hydrocarbons, a stream D62 comprising C5 and C6 hydrocarbons, a stream D31 comprising propylene, a stream D51 comprising propylene, a stream D63 comprising propylene, a stream D61 comprising butenes, a stream D64 comprising butenes, and a stream D52 comprising ethane and ethylene.

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