Method for preparing C2-C4 olefins from methanol and ethanol

Abstract

The present invention provides a process for producing C2-C4 olefins from methanol and ethanol, comprising: A) feeding a feed stream A containing methanol, with or without ethanol, to a dimethyl ether fixed-bed reactor to catalytically convert the methanol to dimethyl ether to obtain a product stream A1 containing dimethyl ether, methanol, ethanol, and water vapor; B) Stream A1 is mixed with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and treated in an olefin fixed bed reactor to produce C2-C4 olefins, C5-C6 hydrocarbons and C7 + catalytically converting the hydrocarbon-containing crude product stream B into a crude product stream B comprising hydrocarbons; C) cooling crude product stream B to obtain hydrocarbon crude product stream C; D) separating the hydrocarbon crude product stream C into a valuable product stream comprising propylene, optionally a valuable product stream comprising ethylene, a valuable product stream comprising butenes, at least one C5-C6 hydrocarbon-containing recycle stream, and a C6 + separating the hydrocarbon-containing by-product stream into at least one by-product stream; 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 valuable product stream comprising propylene, a valuable product stream comprising ethylene, and optionally a valuable product stream comprising butenes; G)C6 + disposing of said by-product stream comprising hydrocarbons; Including, the methanol- and ethanol-based stream A contains less than 1% by weight or 30% to 50% by weight of ethanol, in which case 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, based on 100% by weight of C2-C4 olefins, and furthermore 0% to 40% of said ethylene, 40% to 90% of said propylene and 0% to 100% of said butenes, based on the C2-C4 olefins present in the crude product stream B, are recycled to step B); Alternatively, the methanol and ethanol based stream A comprises 1% to 30% by weight of ethanol, in which case 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 valuable products, based on 100% by weight of C2-C4 olefins, and further 0% to 100% by weight of said ethylene, 0% to 20% by weight of said propylene and 40% to 100% by weight of said butenes, based on the C2-C4 olefins present in the crude product stream B, are recycled to step B).

Description

[Technical Field]

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

[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 at a temperature of about 480°C using a zeolite catalyst.

[0003] U.S. Patent Application Publication No. 2010 / 145125(A1) discloses a method for preparing light olefins by the conversion of methanol and ethanol. The method includes feeding a first partial feed to a reaction zone containing a catalyst through a distributor at the base of a fluidized-bed reactor, feeding a second partial feed to the reaction zone from at least one point above the distributor, and contacting and reacting the feed with the catalyst to obtain a stream containing ethylene and propylene. The first and second partial feeds each independently contain methanol and / or ethanol, provided that the total feed contains methanol and ethanol, and the weight ratio of methanol to ethanol in the total feed ranges from 99:1 to 0.1:1.

[0004] Chinese Patent No. 216106699 discloses a method for preparing ethylene, propylene, and butenes by catalytic dehydration of methanol. The system includes a reaction unit and a separation unit. The reaction unit includes a pre-reactor, a process vapor column, and a main reactor. The separation unit includes a quencher and a compressor. The main reactor contains a ZSM-5 molecular sieve catalyst. The separation unit includes an ethylene column, a propylene column, and a butene column. Ethane, propane, butane, and C5 and C6 hydrocarbons are partially recycled to the main reactor. Other components are discharged as by-products. The unit can also be used to produce butenes while reducing the amount of recycled hydrocarbons and lowering the unit's energy consumption. Only saturated hydrocarbons are recycled to the main reactor.

[0005] Chinese Patent No. 110218138 discloses a process for increasing the olefin yield in a methanol-to-propylene process (MTP process), in which 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 rate is 210 t / h, and the recycled C2, C4, and C5-C7 hydrocarbon feed rates are 27 t / h, 40 t / h, and 150 t / h, respectively. Ethylene production is 1.5 t / h; propylene production is 60 t / h. There is no mention of ethanol co-feeding. The valuable product obtained is predominantly propylene. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] US Patent Application Publication No. 2010 / 145125 [Patent Document 2] Chinese Patent No. 216106699 [Patent Document 3] Chinese Patent No. 110218138 Summary of the Invention [Problem to be solved by the invention]

[0007] It is an object of the present invention to provide a flexible process for preparing C2-C4 olefins from methanol in a methanol to olefins process (MTO process), which allows for a wide variation in the proportions of ethylene, propylene and butenes in the valuable product stream obtained from the process, and an overall reduction in the amount of recycle stream recycled to the MTO process. [Means for solving the problem]

[0008] The object is to provide a process for producing C2-C4 olefins from methanol, with or without ethanol, comprising: A) feeding a feed stream A comprising methanol, with or without ethanol, to a dimethyl ether fixed bed reactor to catalytically convert the methanol to dimethyl ether to obtain a product stream A1 comprising dimethyl ether, with or without ethanol and ethylene, methanol, and water vapor; B) Stream A1 is mixed with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and treated in an olefin fixed bed reactor to produce C2-C4 olefins, C5-C6 hydrocarbons and C7 + catalytically converting the hydrocarbon-containing crude product stream B into a crude product stream B comprising hydrocarbons; C) cooling crude product stream B to obtain hydrocarbon crude product stream C; D) separating the hydrocarbon crude product stream C into a valuable product stream comprising propylene, optionally a valuable product stream comprising ethylene, a valuable product stream comprising butenes, at least one C5-C6 hydrocarbon-containing recycle stream, and a C6 + separating the hydrocarbon-containing by-product stream into at least one by-product stream; 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 R; F) obtaining a valuable product stream comprising propylene, a valuable product stream comprising ethylene, and optionally a valuable product stream comprising butenes; G)C6 + disposing of said by-product stream comprising hydrocarbons; Including, the methanol- and ethanol-based stream A contains less than 1% by weight or 30% to 50% by weight of ethanol, in which case 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, based on 100% by weight of C2-C4 olefins obtained as valuable products, and furthermore 0% to 40% of said ethylene, 40% to 90% of said propylene and 0% to 100% of said butenes, based on the C2-C4 olefins present in the crude product stream B, are recycled to step B); Alternatively, the methanol- and ethanol-based stream A contains 1% and 30% by weight of ethanol, in which case 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 valuable products, based on 100% by weight of C2-C4 olefins, and furthermore 0% to 100% of said ethylene, 0% to 20% of said propylene and 40% to 100% of said butenes, based on the C2-C4 olefins present in the crude product stream B, are recycled to step B).

[0009] In the process of the present invention, 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, based on 100% by weight of the C2-C4 olefins obtained as valuable products. Furthermore, 0% to 40% of ethylene, 40% to 90% of propylene, and 0% to 100% of butenes, based on the C2-C4 olefins present in crude product stream B, 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 less than 1% by weight, in particular 0% by weight. Alternatively, the economics of the process can be improved if the proportion of ethanol in the alcohol fed to the process is 30% to 50% by weight.

[0010] Alternatively, the proportion of ethanol in the alcohol fed to the overall process may be between 1% and 30% by weight, with 0% to 20% by weight of ethylene, 70% to 100% by weight of propylene and 1% to 20% by weight of butenes being obtained as valuable products, based on 100% by weight of C2-C4 olefins, and further with 0% to 100% of ethylene, 0% to 20% of propylene and 40% to 100% of butenes being recycled to step B), based on the C2-C4 olefins present in crude product stream B.

[0011] It has been found that by varying the recycle form, it is possible to achieve product compositions that would otherwise only be possible through very complex catalyst optimization. Furthermore, the addition of ethanol in the identified preferred range significantly reduces the amount of recycle stream and by-products. This significantly reduces the energy demand of the process, for example, because less mass must be separated in a complex manner downstream of the reactor.

[0012] In a preferred embodiment, the method of the present invention comprises the following steps: A1) feeding a feed stream A comprising methanol, with or without ethanol, into a dimethyl ether fixed bed reactor to catalytically convert the methanol into dimethyl ether and optionally the ethanol into ethylene to obtain a product stream A1 comprising dimethyl ether, with or without ethanol and ethylene, 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 430-500°C and feeding it to an olefin fixed bed reactor, where the heating may be performed before mixing of the individual substreams to obtain the feed stream A2 of step A2; B2) The feed stream A2 is treated at a temperature in the range of 430-520°C with ethylene, propylene, butene, further C2-C6 hydrocarbons, C7 + C1) catalytically converting the crude product gas stream B into a crude product gas stream B containing hydrocarbons, methanol and water vapor; C2) cooling the crude product gas stream B to a temperature in the range of 170-220°C by heat exchange with feed stream A2 in one or more heat exchangers; C2) further cooling the crude product gas stream B to a temperature in the range of 30-60°C while condensing water and methanol by contacting it with at least one water-containing quench circulating stream K to obtain a water- and methanol-free hydrocarbon crude product gas stream C; D) treating the hydrocarbon crude product gas stream C with a valuable product stream comprising propylene, optionally a valuable product stream comprising ethylene, a valuable product stream comprising butenes, at least one recycle stream comprising C5-C6 hydrocarbons, and a valuable product stream comprising C6 + separating the product into at least one by-product stream comprising hydrocarbons.

[0013] In step A1), a feed stream A comprising methanol and ethanol is fed to a dimethyl ether fixed bed reactor where the methanol is catalytically converted to dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor.

[0014] When 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, based on 100% by weight of C2-C4 olefins obtained as valuable products, the proportion of ethanol in the total amount of alcohols ethanol and methanol fed to the process can be less than 1% by weight. Alternatively, the proportion of ethanol can be increased to 30% to 50% by weight to achieve a more favorable operating window.

[0015] Alternatively, an advantageous proportion of ethanol in the total amount of alcohols ethanol and methanol fed to the process is 1% to 30% by weight, in which case 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, based on 100% by weight of C2-C4 olefins obtained as valuable products.

[0016] 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 containing methanol, with or without ethanol, is heated to a temperature above 250°C and fed to the fixed-bed reactor. The catalyst used is typically gamma alumina. The conversion temperature is between 250 and 450°C, and the pressure is between 1 and 25 bar, e.g., 4 bar. The methanol conversion is typically between 50% and 90%, preferably between 65% and 85%, e.g., 75%.

[0017] In the case of small amounts of ethanol, stream A can be preheated to a temperature of 250-300° C., for example 275° C. The product gas stream A1 leaving the reactor is then generally at a temperature of 350-400° C., for example 370° C. This stream is then cooled by heat exchange with stream A to a temperature generally of 180-250° C.

[0018] If the ethanol content in stream A is relatively high, stream A may instead be heated to a temperature of up to 450°C and the reactor operated adiabatically. Alternatively, the reactor may be designed as a heated reactor, in which case stream A only needs to be heated to a temperature of up to 400°C.

[0019] In step A2), at least a portion of stream A1 is mixed with a hydrocarbon recycle stream R containing C2-C6 hydrocarbons and a steam stream to obtain feed gas stream A2. Typically, this portion of stream A1 is at least 50 wt. %, preferably up to 90 wt. A further portion A1-2 of stream A1, preferably at least 10 wt. %, can be fed directly to one or more trays of an olefin fixed-bed reactor. This portion of stream A1 is typically cooled, preferably to a temperature in the range of 30-60° C., before being fed to the trays of the olefin fixed-bed reactor. This substream, stream A1-2, is preferably fed to the reactor in liquid form.

[0020] The cooling by substream A1-2 can be omitted if the olefin fixed bed reactor is operated and cooled isothermally, as can be done, for example, by the method described in WO 2017 / 102096 A1.

[0021] For example, a heat transfer surface may be installed in an olefin fixed-bed reactor, and the heat transfer surface may be operated, for example, using liquid salt or high-pressure steam as a heat transfer medium. The flow of the heat transfer medium through the heat transfer surface in the reactor removes the generated reaction heat from the reactor, which is therefore operated isothermally. In order to establish the desired product distribution in product gas stream B, it is also possible to feed substream A1-2 to an intermediate stage of the olefin fixed-bed reactor.

[0022] The at least one hydrocarbon recycle stream R resulting from the removal of C2-C4 olefins generally comprises C1-C6 hydrocarbons. Depending on the proportion of ethylene, propylene and butenes obtained as valuable products in step E), the at least one hydrocarbon recycle stream generally comprises C2-C4 hydrocarbons in a total amount of 50% to 90% by weight. The at least one hydrocarbon recycle stream before mixing is generally at a temperature in the range of 100 to 175°C, preferably in the range of 130 to 160°C.

[0023] The product stream A1 from the dimethyl ether fixed-bed reactor is also mixed with a steam stream, which generally has a temperature in the range of 100-200°C, preferably 100-150°C. The feed stream A2 thus obtained generally contains 20-70% by weight, preferably 30-60% by weight, of steam.

[0024] 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 to C6 hydrocarbons.

[0025] In step B1), feed stream A2 is heated in one or more heat exchangers to a temperature typically in the range of 430-500°C and fed to an olefin fixed-bed reactor. Heating may occur prior to the mixing of the individual substreams in step A2).

[0026] Typically, feed stream A2, when fed to the olefin fixed bed reactor, is at a temperature in the range of 430-500° C., e.g., 470° C. Feed stream A2 can be heated to that temperature by heat exchange with crude product gas stream B from the olefin fixed bed reactor, by direct electrical heating, or by heating by combustion of a separate fossil energy carrier.

[0027] This is followed in step B2) by catalytic conversion in an olefin fixed bed reactor to produce ethylene, propylene, butenes, further C2-C6 hydrocarbons, C7 +A product gas stream B is obtained which comprises hydrocarbons, methanol and water vapor. The conversion is generally carried out over a zeolite catalyst, preferably a catalyst based on ZSM-5 zeolite. The reaction temperature is generally between 430 and 500°C, preferably between 460 and 480°C. The pressure is generally between 1.3 and 2.5 bar. The obtained 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 to C6 hydrocarbons, in particular butenes, as well as saturated C4 and C5 hydrocarbons and C6 + hydrocarbons, plus 0.01% to 1.5% by weight of methanol and dimethyl ether.

[0028] The olefin fixed bed reactor generally takes the form of a tray reactor. The number of trays is preferably 4 to 6. In one embodiment, up to a total of 50 wt. % of gas stream A is fed directly to one or more trays of the olefin fixed bed reactor, preferably to all trays of the olefin fixed bed reactor. In a further embodiment, methanol is fed directly to one or more trays of the olefin fixed bed reactor, preferably to all trays of the olefin fixed bed reactor.

[0029] The crude product gas stream B leaving the reactor is generally at a temperature of between 430 and 520°C, preferably between 460 and 480°C.

[0030] 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 170-220° C. After this cooling step, the temperature of the crude product gas stream B is generally between 160 and 220° C., preferably between 170 and 210° C., for example 190° C.

[0031] In a preferred step C2), the crude product gas stream B is further cooled to a temperature in the range of 30-60°C by contacting it with one or more water-containing quench recycle streams, condensing the water and methanol, to obtain a water- and methanol-free hydrocarbon crude product gas stream C. The hydrocarbon crude product gas stream C thus obtained essentially contains ethylene, propylene, further C2-C6 hydrocarbons and C7 + Contains hydrocarbons.

[0032] In step D), one or more product streams comprising C2-C4 olefins are separated from the hydrocarbon crude product gas stream C to obtain at least one recycle stream R comprising C2-C6 hydrocarbons. The recycle stream R (as a whole) may comprise or be formed from a plurality of individual recycle streams R1, R2, R3, etc. Typically, the overall recycle stream R comprising C2-C6 hydrocarbons comprises essentially, i.e. to an extent of more than 95% by weight, C2-C6 hydrocarbons.

[0033] Generally, step D) includes steps D1) to D7): D1) Compressing the hydrocarbon crude product gas stream C to produce propylene and C4, C5 and C6 + obtaining a liquid hydrocarbon stream D11 comprising hydrocarbons and a gaseous hydrocarbon stream D12 comprising ethane, ethene and propylene; D2) separating water from said liquid hydrocarbon stream D11 by phase separation to obtain a liquid hydrocarbon stream D21; D3) Separating a propylene-containing stream D31 from the liquid hydrocarbon stream D21 to obtain C4, C5 and C6 + obtaining a stream D32 containing propylene and C4 hydrocarbons; or separating the stream D31 containing propylene and C4 hydrocarbons into C4, C5 and C6 + obtaining a hydrocarbon-containing stream D32; D4)C6 + The hydrocarbon-containing by-product stream D41 is separated into C4, C5 and C6 +separating said stream D32 containing hydrocarbons to obtain a stream D42 containing C4, C5 and C6 hydrocarbons; stream D41 optionally containing aromatic C6 hydrocarbons and stream D42 containing aliphatic C6 hydrocarbons; D5) separating a stream D51 comprising propylene from said gaseous hydrocarbon stream D12 comprising ethane, ethene and propylene to obtain a stream D52 comprising ethane and ethene; D6) separating a stream D61 containing butenes from said stream D42 containing C4, C5 and C6 hydrocarbons to obtain a stream D62 containing C5 and C6 hydrocarbons; and / or separating a stream D63 containing propylene from stream D31 to obtain a stream D64 containing butenes; D7) Obtaining at least one recycle stream R from one or more of said streams selected from stream D42 comprising C4, C5 and C6 hydrocarbons, stream D62 comprising C5 and C6 hydrocarbons, said stream D31 comprising propylene, stream D51 comprising propylene, stream D63 comprising propylene, stream D61 comprising butenes, stream D64 comprising butenes, and said stream D52 comprising ethane and ethene.

[0034] Steps D3), D4), D5) and D6) are carried out in standard distillation equipment. Useful distillation equipment includes, in principle, equipment known to those skilled in the art for such separation operations. As well as the actual column body with its internal structure, the distillation column also typically comprises an upper condenser and a reboiler. The column body may, for example, comprise structured packing, random packing or trays. The distillation equipment may be designed and operated according to the common sense of those skilled in the art.

[0035] In step E), a portion of the C2-C4 olefins and at least a portion of the C5-C6 hydrocarbons are recycled to step B) as one or more hydrocarbon recycle streams R.

[0036] In step F), a valuable product stream comprising propylene, a valuable product stream comprising ethylene and optionally a valuable product stream comprising butenes is obtained.

[0037] Propylene can be obtained as a valuable product from streams D31 or D63 and D51. Ethylene can be obtained as a valuable product from stream D52. Butenes can be obtained from streams D61 and / or D64.

[0038] The recycle stream(s) R may be obtained from one or more of the above-mentioned streams D31, D42, D51, D52, D61, D62, D63 and D64.

[0039] 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, and further, based on the C2-C4 olefins present in 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), or based on 100% by weight of the C2-C4 olefins obtained as valuable products, 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 valuable products, and further, based on the C2-C4 olefins present in crude product stream B, 0% to 100% of ethylene, 0% to 20% by weight of propylene and 40% to 100% of butenes are recycled to step B).

[0040] In step G), C6 + A by-product stream containing hydrocarbons exits the process, which may be stream D41.

[0041] The present invention will now be described in detail by way of the following examples. DETAILED DESCRIPTION OF THE INVENTION

[0042] Example The following ranges 1 to 4 were simulated for the feed stream composition (ethanol content), crude product stream composition (ratio of C2 / C3 olefins to C4 / C3 olefins), and the resulting valuable product composition (proportions of C2, C3, and C4 olefins). The values ​​are weight ratios.

[0043] To confirm the preferred ranges, laboratory-scale catalytic experiments were performed, based on which the expected conversions and mass flow rates were calculated for an industrial process with a pre-reactor, tray reactor, and separation section. Optimization of this system resulted in ranges 1-4, specified in Table 1. Table 2 shows the relevant flow rates for exemplary points determined in ranges 1 and 2. Similar exemplary values ​​for ranges 3 and 4 are listed in Table 3. In each case, the addition of ethanol allows for the minimization of the relative recycle and by-product flows, thus improving the energy and mass efficiency of the process.

[0044] [Table 1]

[0045] The results of the simulations are summarized in Tables 2 and 3. All figures are by weight.

[0046] [Table 2]

[0047] [Table 3]

Claims

1. C ２ ~C ４ 1. A process for making olefins from methanol and ethanol, comprising: A) feeding a feed stream A comprising methanol, with or without ethanol, to a dimethyl ether fixed bed reactor to catalytically convert the methanol to dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor; B) Stream A1 is mixed with C ２ ~C ６ and mixing it with at least one hydrocarbon recycle stream R containing hydrocarbons and subjecting it to an olefin fixed bed reactor C ２ ~C ４ Olefin, C ５ ~C ６ Hydrocarbons and C ７ ＋ catalytically converting the hydrocarbon-containing crude product stream B into a crude product stream B comprising hydrocarbons; C) cooling crude product stream B to obtain hydrocarbon crude product stream C; D) converting the hydrocarbon crude product stream C into a valuable product stream comprising propylene, optionally a valuable product stream comprising ethylene, at least one C ５ ~C ６ a hydrocarbon-containing recycle stream, and C ６ ＋ separating the hydrocarbon-containing by-product stream into at least one by-product stream; E) C ２ ~C ４ Some olefins and C ５ ~C ６ recycling at least a portion of the hydrocarbons to step B) as one or more hydrocarbon recycle streams; F) obtaining a valuable product stream comprising propylene, a valuable product stream comprising ethylene, and optionally a valuable product stream comprising butenes; G) C ６ ＋ disposing of said by-product stream comprising hydrocarbons; Including, The methanol and ethanol-based stream A contains less than 1% by weight or between 30% and 50% by weight of ethanol, in which case the valuable product C is obtained. ２ ~C ４ Based on 100% by weight of olefins, 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, and furthermore, the C present in the crude product stream B is ２ ~C ４ Based on olefins, 0 to 40% by weight of the ethylene, 40 to 90% by weight of the propylene, and 0 to 100% by weight of the butenes are recycled to step B). Alternatively, the methanol and ethanol-based stream A contains 1% to 30% by weight of ethanol, in which case the C obtained as a valuable product ２ ~C ４ Based on 100% by weight of olefins, 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 valuable products, and furthermore, the C present in the crude product stream B is ２ ~C ４ The process wherein, based on olefins, 0% to 100% of the ethylene, 0% to 20% of the propylene, and 40% to 100% of the butenes are recycled to step B).

2. 2. The method of claim 1, wherein steps A) to D) comprise 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 to catalytically convert the methanol to dimethyl ether to obtain a product stream A1 comprising dimethyl ether, methanol, ethanol and water vapor; A2) converting at least a portion of the product stream A1 into C ２ ~C ６ mixing with at least one hydrocarbon recycle stream R comprising hydrocarbons and a steam stream to obtain a second feed stream A2; B1) heating said second feed stream A2 in one or more heat exchangers to a temperature in the range of 430-500°C and feeding it to an olefin fixed bed reactor, said heating optionally occurring prior to said mixing of the individual substreams to obtain said feed stream A2 in step A2; B2) catalytically converting feed stream A2 at a temperature in the range of 430-520°C to produce ethylene, propylene, butenes, additional C ２ ~C ６ Hydrocarbons, C ７ ＋ obtaining a crude product gas stream B comprising hydrocarbons, methanol and water vapor; C1) cooling crude product gas stream B to a temperature in the range of 170-220°C by heat exchange with feed stream A2 in one or more heat exchangers; C2) further cooling the crude product gas stream B to a temperature in the range of 30-60°C while condensing water and methanol by contacting it with at least one water-containing quench recycle stream K to obtain a water- and methanol-free hydrocarbon crude product gas stream C2; D) separating the hydrocarbon raw product gas stream C into a valuable product stream comprising propylene, optionally a valuable product stream comprising ethylene, a valuable product stream comprising butenes, and C ５ ~C ６ at least one recycle stream comprising hydrocarbons; ６ ＋ separating the product into at least one by-product stream comprising hydrocarbons. A method comprising:

3. 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 produce propylene and C ４ , C ５ and C ６ ＋ obtaining a liquid hydrocarbon stream D11 comprising hydrocarbons and a gaseous hydrocarbon stream D12 comprising ethane, ethene and propylene; D2) separating water from said liquid hydrocarbon stream D11 by phase separation to obtain a liquid hydrocarbon stream D21; D3) separating a propylene-containing stream D31 from said liquid hydrocarbon stream D21 to form C ４ , C ５ and C ６ ＋ obtaining a hydrocarbon-containing stream D32; or propylene and C ４ The hydrocarbon-containing stream D31 is separated to obtain C ４ , C ５ and C ６ ＋ obtaining a hydrocarbon-containing stream D32; D4) C ６ ＋ The hydrocarbon-containing by-product stream D41 is ４ , C ５ and C ６ ＋ C is separated from the hydrocarbon-containing stream D32 ４ , C ５ and C ６ obtaining a stream D42 comprising hydrocarbons; stream D41 optionally comprising aromatic C ６ Stream D42 contains aliphatic C ６ Contains hydrocarbons; D5) separating a stream D51 comprising propylene from said gaseous hydrocarbon stream D12 comprising ethane, ethene and propylene to obtain a stream D52 comprising ethane and ethene; D6) butene-containing stream D61 is treated with C ４ , C ５ and C ６ C is separated from the hydrocarbon-containing stream D42 ５ and C ６ obtaining a hydrocarbon-containing stream D62; and / or separating a propylene-containing stream D63 from stream D31 to obtain a butene-containing stream D64; D7) at least one recycle stream R is mixed with C ４ , C ５ and C ６ Hydrocarbon-containing streams D42, C ５ and C ６ from one or more of said streams selected from the hydrocarbon-containing stream D62, said propylene-containing stream D31, said propylene-containing stream D51, said propylene-containing stream D63, the butene-containing stream D61, the butene-containing stream D64, and said ethane and ethene-containing stream D52. A method comprising:

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