Method for producing c2-c4 olefins from methanol and ethanol
Patent Information
- Application Number
- EP2023764656
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-10-25
- Filing Date
- 2023-09-04
- Publication Date
- 2025-07-23
AI Technical Summary
Current processes for producing C2-C4 olefins from methanol struggle with flexibility in product distribution and high recycle stream and by-product amounts, leading to increased energy consumption and complexity.
A process involving the catalytic conversion of methanol and ethanol in a dimethyl ether fixed bed reactor, followed by mixing with hydrocarbon recycle streams in an olefin fixed bed reactor, allowing for flexible product distribution and reduced recycle streams through careful temperature and composition control, and subsequent separation to achieve desired C2-C4 olefin ratios.
This approach enables flexible production of ethylene, propylene, and butenes with reduced recycle streams and by-products, significantly lowering energy requirements and process complexity by optimizing product compositions and minimizing the need for complex catalyst optimization.
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Abstract
Description
[0001] Process for the production of C2-C4 olefins from methanol and ethanol
[0002] Description
[0003] The invention relates to a process for the preparation of C2-C4 olefins from methanol and optionally ethanol.
[0004] It is known to produce propylene by converting a methanol / dimethyl ether mixture in a fixed-bed reactor (methanol-to-propylene, MTP reactor). Conventional fixed-bed reactors operate with zeolite catalysts at temperatures of approximately 480°C.
[0005] US 2010 / 145125 A1 discloses a process for producing light olefins by converting methanol and ethanol. The process comprises feeding a first feed portion via a distributor at the bottom of a fluidized-bed reactor to a reaction zone containing a catalyst, feeding a second feed portion from at least one location above the distributor to the reaction zone, contacting the feed with the catalyst, and reacting to form a stream containing ethylene and propylene. The first and second feed portions each independently comprise methanol and / or ethanol, with the proviso that the feed as a whole comprises both methanol and ethanol, and the weight ratio of methanol to ethanol in the feed as a whole is in the range from 99:1 to 0.1:1.
[0006] CN 216106699 U discloses a process for producing ethylene, propylene, and butenes by catalytic dehydration of methanol. The system comprises a reaction unit and a separation unit, with the reaction unit comprising a pre-reactor, a process vapor column, and a main reactor, and the separation unit comprising a quencher and a compressor. The main reactor contains a ZSM-5 molecular sieve catalyst, and the separation unit comprises an ethylene column, a propylene column, and a butene column. Ethane, propane, butane, and Cs and Css hydrocarbons are partially recycled to the main reactor, while other components are discharged as byproducts. The unit can also 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.
[0007] CN 110218138 A discloses a process for increasing the yield of olefin in a methanol-to-propylene process (MTP process) in which C2 hydrocarbons, C4 hydrocarbons, and Cs-Cy hydrocarbons are recycled to the MTP reactor. In one example, in a 500,000 t / year methanol-to-propylene plant, the methanol feed is 210 t / h and the rates of recycled C2, C4, and Cs-Cy hydrocarbons are 27 t / h, 40 t / h, and 150 t / h, respectively. Ethylene production is 1.5 t / h, and propylene production is 60 t / h. The co-feed of ethanol is not mentioned. Propylene is obtained predominantly as the product of value.The object of the invention is to provide a flexible process for producing C2-C4 olefins from methanol in a methanol-to-olefin process (MTO process), in which the proportions of ethylene, propylene and butenes in the valuable product streams obtained from the process can be varied within wide ranges and the amount of recycle streams recycled to the MTO process can be reduced overall.
[0008] The problem is solved by a process for the production of C2-C4 olefins from methanol and optionally ethanol with the following steps:
[0009] A) feeding a feed stream A containing methanol and optionally ethanol into a dimethyl ether fixed bed reactor and catalytically converting methanol to dimethyl ether, whereby a product stream A1 containing dimethyl ether, methanol, steam and optionally ethanol and ethylene is obtained;
[0010] B) Mixing the stream A1 with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and catalytic conversion in an olefin fixed bed reactor to a crude product stream B containing C2-C4 olefins, Cs-Cß hydrocarbon and Cy + -hydrocarbons;
[0011] C) cooling the crude product stream B to obtain a hydrocarbon crude product stream C;
[0012] D) Separation of the hydrocarbon crude product stream C into a propylene-containing valuable product stream, optionally an ethylene-containing valuable product stream, a butene-containing valuable product stream, at least one Cs-Cß-hydrocarbon-containing recycle stream and at least one C6 + -hydrocarbon-containing by-product stream;
[0013] E) recycling a portion of the C2-C4 olefins and at least a portion of the Cs-Cß hydrocarbons as one or more hydrocarbon recycle streams R in step B);
[0014] F) obtaining a valuable product stream containing propylene, a valuable product stream containing ethylene and optionally a valuable product stream containing butenes;
[0015] G) Removal of C6 +-hydrocarbon-containing by-product stream; characterized in that stream A, based on methanol and ethanol, contains < 1 wt.% or 30 to 50 wt.% ethanol, wherein, based on 100 wt.% of the C2-C4 olefins obtained as products of value, 30 to 60 wt.% ethylene, 30 to 60 wt.% propylene and 0 to 30 wt.% 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), or stream A, based on methanol and ethanol, contains 1 and 30 wt.% ethanol, wherein, based on 100 wt.% of the C2-C4 olefins obtained as products of value, 0 to 20 wt.% ethylene, 70 to 100 wt.% propylene and 1 to 20 wt.-% butenes are recovered as valuable products, and, based on the C2-C4 olefins contained in the crude product stream B, 0 to 100% of the ethylene, 0 to 20% of the propylene and 40 to 100% of the butenes are recycled to step B).
[0016] In the process according to the invention, from 30 to 60% by weight of ethylene, from 30 to 60% by weight of propylene, and from 0 to 30% by weight of butenes can be obtained as products of value, based on 100% by weight of the C2-C4 olefins obtained as products of value, and from 0 to 40% of the ethylene, from 40 to 90% of the propylene, and from 0 to 100% of the butenes can be recycled to step B), based on the C2-C4 olefins present in the crude product stream B. The proportion of ethanol in the total alcohols ethanol and methanol fed to the process can be < 1% by weight, in particular 0% by weight. Alternatively, to improve process economics, the proportion of ethanol in the alcohols fed to the process can be from 30 to 50% by weight.
[0017] Alternatively, the proportion of ethanol in the total alcohols fed to the process can also be between 1 and 30 wt.%, wherein, based on 100 wt.% of the C2-C4 olefins obtained as products of value, 0 to 20 wt.% ethylene, 70 to 100 wt.% propylene and 1 to 20 wt.% 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 the ethylene, 0 to 20% of the propylene and 40 to 100% of the butenes are recycled to step B).
[0018] It was found that the modified recycle variants allow product compositions to be achieved that would otherwise only be possible through very complex catalyst optimization. Furthermore, the addition of ethanol within the determined preferred ranges results in a significantly reduced amount of recycle stream and by-products. This significantly reduces the energy requirements of the process, for example, since less mass needs to be separated downstream of the reactor.
[0019] In a preferred embodiment, the method according to the invention comprises the steps:
[0020] A1) feeding a feed stream A containing methanol and optionally ethanol into a dimethyl ether fixed bed reactor and catalytically converting methanol to dimethyl ether and optionally ethanol to ethylene, whereby a product stream A1 containing dimethyl ether, methanol, steam and optionally ethanol and ethylene is obtained;
[0021] A2) Mixing at least a portion of the product stream A1 with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and a steam stream, thereby obtaining a second feed stream A2; B1) Heating the second feed stream A2 in one or more heat exchangers to a temperature in the range from 430 to 500°C and feeding it into an olefin fixed-bed reactor, wherein the heating can also take place before the mixing of individual partial streams to form the feed stream A2 in step A2);
[0022] B2) catalytic conversion of the feed stream A2 at a temperature in the range of 430 to 520°C to a crude product gas stream B containing ethylene, propylene, butenes, further C2-C6 hydrocarbons, C7 + -hydrocarbons, methanol and water vapor;
[0023] C1 ) Cooling the crude product gas stream B in one or more heat exchangers to a temperature in the range of 170 to 220°C by heat exchange with the feed stream A2;
[0024] C2) further cooling the crude product gas stream B to a temperature in the range from 30 to 60°C by bringing it into contact with at least one water-containing quench recycle stream K, whereby water and methanol are condensed out and a hydrocarbon crude product gas stream C depleted in water and methanol is obtained;
[0025] D) Separation of the hydrocarbon crude product gas stream C into a propylene-containing valuable product stream, optionally an ethylene-containing valuable product stream, a butene-containing valuable product stream, at least one Cs-Cß-hydrocarbon-containing recycle stream and at least one C6 + -hydrocarbon-containing by-product stream.
[0026] In step A1), a feed stream A containing methanol and ethanol is fed into a dimethyl ether fixed bed reactor and methanol is catalytically converted to dimethyl ether, whereby a product stream A1 containing dimethyl ether, methanol, ethanol and steam is obtained.
[0027] If, based on 100 wt. % of the C2-C4 olefins obtained as valuable products, 30 to 60 wt. % ethylene, 30 to 60 wt. % propylene, and 0 to 30 wt. % butenes are obtained as valuable products, the proportion of ethanol in the total alcohols (ethanol and methanol) fed into the process can be <1 wt. %. Alternatively, the proportion of ethanol can be increased to 30 to 50 wt. % to achieve a more favorable operating window.
[0028] Alternatively, an advantageous proportion of ethanol in the total alcohols ethanol and methanol fed to the process is 1 to 30 wt.% if, based on 100 wt.% of the C2-C4 olefins obtained as valuable products, 1 to 20 wt.% ethylene, 70 to 100 wt.% propylene and 0 to 20 wt.% butenes are obtained as valuable products.
[0029] The dimethyl ether fixed-bed reactor can be designed in various ways, depending on the precise composition of the feed gas stream. Generally, the feed gas stream A, which contains methanol and optionally ethanol, is heated to a temperature above 250 °C and fed into the fixed-bed reactor. Gamma-alumina is generally used as the catalyst. The reaction temperature is between 250 and 450 °C, and the pressure is between 1 and 25 bar, for example, 4 bar. The methanol conversion is generally between 50 and 90%, preferably between 65 and 85%, for example, 75%.
[0030] With low ethanol contents, stream A can be preheated to a temperature of 250 to 300 °C, for example, 275 °C. The product gas stream A1 leaving the reactor then has a temperature of generally 350 to 400 °C, for example, 370 °C. This stream is then cooled by heat exchange with stream A to a temperature of generally 180 to 250 °C.
[0031] With higher ethanol content in stream A, stream A can also be heated to temperatures 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 only needs to be heated to temperatures of up to 400 °C.
[0032] In a step A2), at least a portion of this stream A1 is mixed with a hydrocarbon recycle stream R comprising C2-C6 hydrocarbons and a steam stream to obtain a feed gas stream A2. This portion of stream A1 generally amounts to at least 50% by weight and preferably up to 90% by weight. A further portion A1-2 of stream A1, preferably at least 10% by weight, can be fed directly to one or more trays of the olefin fixed-bed reactor. This portion of stream A1 is generally cooled, preferably to a temperature in the range from 30 to 60°C, before being fed into the trays of the olefin fixed-bed reactor. This substream A1-2 is preferably fed into the reactor in liquid form.
[0033] Cooling by substream A1-2 can also be omitted if the olefin fixed-bed reactor is operated and cooled isothermally. Isothermal operation can be carried out, for example, in the manner described in WO 2017 / 102096 A1. Heat exchanger surfaces can be installed in the olefin fixed-bed reactor, which are operated, for example, with molten salt or high-pressure steam as the heat transfer medium. As the heat transfer medium flows through the heat exchanger surfaces in the reactor, the resulting reaction heat is removed from the reactor, thus operating it isothermally. To adjust the desired product distribution in product gas stream B, a substream A1-2 can also be fed to an intermediate stage of the olefin fixed-bed reactor.
[0034] The at least one hydrocarbon recycle stream R, which originates from the separation of the C2-C4 olefins, generally comprises C1-C8 hydrocarbons. Depending on the proportions of ethylene, propylene, and butenes obtained as products of value in step E), the at least one hydrocarbon recycle stream contains C2-C4 hydrocarbons, generally in total amounts of 50 to 90% by weight. Before mixing, the at least one hydrocarbon recycle stream generally has a temperature in the range from 100 to 175°C, preferably in the range from 130 to 160°C. Product stream A1 from the dimethyl ether fixed-bed reactor is further mixed with a steam stream. The steam stream generally has a temperature in the range from 100 to 200°C, preferably in the range from 100 to 150°C. The feed stream A2 thus obtained generally contains 20 to 70 wt.%, preferably 30 to 60 wt.%, of water vapor.It generally also contains 5 to 10 wt% methanol, 0 to 15 wt% ethanol, 10 to 20 wt% dimethyl ether and 15 to 50 wt% C2-C6 hydrocarbons.
[0035] In step B1), the feed stream A2 is heated in one or more heat exchangers to a temperature generally in the range of 430 to 500°C and fed into an olefin fixed-bed reactor. The heating can also take place before the mixing of individual substreams in step A2).
[0036] Generally, the feed stream A2 has a temperature in the range of 430 to 500°C, for example, 470°C, when fed into the olefin fixed-bed reactor. Heating the feed stream A2 to this temperature can be achieved by heat exchange with the raw product gas stream B of the olefin fixed-bed reactor, direct electrical heating, or heating by combustion of a separate fossil fuel.
[0037] This is followed in step B2) by catalytic conversion in the olefin fixed bed reactor to a product gas stream B containing ethylene, propylene, butenes, further C2-C6 hydrocarbons, C7 + - hydrocarbons, methanol and steam. The reaction is generally carried out over a zeolite catalyst, preferably over a catalyst based on a ZSM-5 zeolite. The reaction temperature is generally from 430 to 500°C, preferably from 460 to 480°C. The pressure is generally from 1.3 to 2.5 bar. The resulting crude product gas stream B2 is preferably composed as follows: from 1 to 15% by weight of ethylene, from 1 to 15% by weight of propylene, from 35 to 80% by weight of water, from 15 to 50% by weight of C2-C6 hydrocarbons, in particular butenes and saturated C4 and C5 hydrocarbons, and also C6 + -hydrocarbons and 0.01 to 1.5 wt.% methanol and dimethyl ether.
[0038] The olefin fixed-bed reactor is generally designed as a tray reactor. The number of trays is preferably 4 to 6. In one embodiment, a total of up to 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.
[0039] The crude product gas stream B has a temperature of generally 430 to 520°C, preferably 460 to 480°C, upon leaving the reactor.
[0040] In a preferred step C1), the crude product gas stream B is cooled in one or more heat exchangers to a temperature in the range of 170 to 220°C by heat exchange with the feed gas stream A2. After this cooling step, the temperature of the crude product gas stream B is generally 160 to 220°C, preferably 170 to 210°C, for example 190°C.
[0041] In a preferred step C2), the crude product gas stream B is further cooled to a temperature in the range from 30 to 60°C by contacting it with one or more water-containing quench cycle streams, whereby water and methanol are condensed out and a water- and methanol-depleted hydrocarbon crude product gas stream C is obtained. The hydrocarbon crude product gas stream C thus obtained essentially contains ethylene, propylene, further C2-C6 hydrocarbons and C7 + -hydrocarbons.
[0042] In a step D), one or more product streams comprising C2-C4 olefins are separated from the crude hydrocarbon gas stream C, and the recycle stream R comprising at least one C2-C8 hydrocarbon is obtained. The (total) recycle stream R can comprise or be formed from a plurality of individual recycle streams R1, R2, R3, etc. In general, the entire recycle stream R comprising C2-C6 hydrocarbons essentially comprises, i.e., >95% by weight, C2-C6 hydrocarbons.
[0043] In general, step D) includes steps D1 ) to D7):
[0044] D1 ) Compression of the hydrocarbon crude product gas stream C, wherein a propylene, C4, C5 and C6 + -a liquid hydrocarbon stream D11 containing hydrocarbons and a gaseous hydrocarbon stream D12 containing ethane, ethene and propylene are obtained;
[0045] D2) separating water from the liquid hydrocarbon stream D11 by phase separation, thereby obtaining a liquid hydrocarbon stream D21;
[0046] D3) Separation of a propylene-containing stream D31 from the liquid hydrocarbon stream D21, wherein a C4, C5 and C6 + -hydrocarbons-containing stream D32 is obtained; or separation of a stream D31 containing propylene and C4 hydrocarbons, wherein a C4, C5 and C6 + -hydrocarbon-containing stream D32 is obtained;
[0047] D4) Separation of a C6 + -hydrocarbon-containing by-product stream D41 from the C4, C5 and C6 + -hydrocarbons-containing stream D32, whereby a stream D42 containing C4, C5 and Cß hydrocarbons is obtained; optionally, the stream D41 contains aromatic Cß hydrocarbons and the stream D42 contains aliphatic Cß hydrocarbons;
[0048] D5) Separation of a propylene-containing stream D51 from the gaseous hydrocarbon stream D12 containing ethane, ethene, and propylene, to obtain a stream D52 containing ethane and ethene; D6) Separation of a butene-containing stream D61 from the C4, C5, and C8 hydrocarbon-containing stream D42, to obtain a C5 and C8 hydrocarbon-containing stream D62; and / or Separation of a propylene-containing stream D63 from the stream D31, to obtain a butene-containing stream D64;
[0049] D7) Obtaining at least one recycle stream R from one or more of the streams selected from the C4, C5 and Cß hydrocarbon-containing stream D42, the C5 and Cß hydrocarbon-containing stream D62, the propylene-containing stream D31, the propylene-containing stream D51, the propylene-containing stream D63, the butene-containing stream D61, the butene-containing stream D64 and the ethane- and ethene-containing stream D52.
[0050] Steps D3), D4), D5), and D6) are carried out in conventional distillation apparatus. Suitable distillation apparatuses are, in principle, those familiar to those skilled in the art for such separation tasks. In addition to the actual column body with internals, the distillation column also contains, as usual, a top condenser and a bottom evaporator. The column body can be equipped, for example, with packings, random packings, or trays. The distillation apparatuses can be designed and operated using the general knowledge of the skilled person.
[0051] In step E), a portion of the C2-C4 olefins and at least a portion of the Cs-Cß hydrocarbons are recycled as one or more hydrocarbon recycle streams R in step B).
[0052] In step F), a valuable product stream containing propylene, a valuable product stream containing ethylene and optionally a valuable product stream containing butenes are obtained.
[0053] Propylene can be recovered as a valuable product from streams D31 or D63 and D51. Ethylene can be recovered as a valuable product from stream D52. Butenes can be recovered from streams D61 and / or D64.
[0054] The return stream(s) R can be obtained from one or more of the streams D31, D42, D51, D52, D61, D62, D63 and D64 described above.
[0055] 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), 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% of the ethylene, 0 to 20% of the propylene and 40 to 100% of the butenes are recycled in step B). In step G), a C6 + A by-product stream containing hydrocarbons is removed from the process. This may be stream D41.
[0056] The invention is further illustrated by the following examples.
[0057] Examples
[0058] The following ranges 1 - 4 of the composition of the feed stream (ethanol content), the crude product stream (ratio of C2 / C3 olefins and C / Cs olefins), and the recovered valuable product (proportions of C2, C3, and C4 olefins) were simulated mathematically. Data are given in weight ratios.
[0059] To determine the preferred ranges, catalytic experiments were conducted on a laboratory scale, and the expected conversions and mass flows in an industrial process with a pre-reactor, tray reactors, and a separation section were calculated. Optimization of this system resulted in the values in ranges 1–4, which are listed in Table 1. Table 2 shows the relevant flow rates for the determined example points in ranges 1 and 2. Similar example values for ranges 3 and 4 are listed in Table 3. By adding ethanol, the relative recycle flow and the relative by-product flow can be minimized, thus improving the energy and mass efficiency of the process.
[0060] Table 1
[0061] The simulation results are summarized in Tables 2 and 3. All data are given in weight ratios. Table 2 Table 3
Claims
Patent claims 1 . Process for the preparation of C2-C4 olefins from methanol and ethanol comprising the steps: A) feeding a feed stream A containing methanol and optionally ethanol into a dimethyl ether fixed bed reactor and catalytically converting methanol to dimethyl ether, whereby a product stream A1 containing dimethyl ether, methanol, ethanol and steam is obtained; B) Mixing the stream A1 with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and catalytic conversion in an olefin fixed bed reactor to a crude product stream B containing C2-C4 olefins, Cs-Css hydrocarbons and C7 + -hydrocarbons; C) cooling the crude product stream B to obtain a hydrocarbon crude product stream C; D) Separation of the hydrocarbon crude product stream C into a propylene-containing valuable product stream, optionally an ethylene-containing valuable product stream, a butene-containing valuable product stream, at least one Cs-Cß hydrocarbon-containing recycle stream and at least one Cß + -hydrocarbon-containing by-product stream; E) recycling a portion of the C2-C4 olefins and at least a portion of the Cß-Cß hydrocarbons as one or more hydrocarbon recycle streams in step B); F) obtaining a valuable product stream containing propylene, a valuable product stream containing ethylene and, optionally, a valuable product stream containing butenes; G) Elimination of Cß +-hydrocarbon-containing by-product stream; characterized in that stream A, based on methanol and ethanol, contains < 1% by weight or 30 to 50% by weight of 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), or stream A, based on methanol and ethanol, contains 1 to 30% by weight of 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 wt.% propylene and 1 to 20 wt.-% butenes are recovered as valuable products, and, based on the C2-C4 olefins contained in the crude product stream B, 0 to 100% of the ethylene, 0 to 20% of the propylene and 40 to 100% of the butenes are recycled to step B). Method according to 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 containing methanol and ethanol into a dimethyl ether fixed bed reactor and catalytically converting methanol to dimethyl ether, whereby a product stream A1 containing dimethyl ether, methanol, ethanol and steam is obtained; A2) mixing at least a portion of the product stream A1 with at least one hydrocarbon recycle stream R containing C2-C6 hydrocarbons and a steam stream, thereby obtaining a second feed stream A2; B1) heating the second feed stream A2 in one or more heat exchangers to a temperature in the range from 430 to 500°C and feeding it into an olefin fixed bed reactor, wherein the heating can also take place before mixing individual partial streams to form the feed stream A2 in step A2); B2) catalytic conversion of the feed stream A2 at a temperature in the range of 430 to 520°C to a crude product gas stream B containing ethylene, propylene, butenes, other C2-C6 hydrocarbons, C7 + -hydrocarbons, methanol and water vapor; C1 ) Cooling the crude product gas stream B in one or more heat exchangers to a temperature in the range of 170 to 220°C by heat exchange with the feed stream A2; C2) further cooling the crude product gas stream B to a temperature in the range from 30 to 60°C by bringing it into contact with at least one water-containing quench recycle stream K, whereby water and methanol are condensed out and a hydrocarbon crude product gas stream C2 depleted in water and methanol is obtained; D) Separation of the hydrocarbon crude product gas stream C into a propylene-containing valuable product stream, optionally an ethylene-containing valuable product stream, a butene-containing valuable product stream, at least one C5-C6 hydrocarbon-containing recycle stream and at least one Ce + -hydrocarbon-containing by-product stream. Process according to claim 1 or 2, characterized in that step D) comprises steps D1) to D7): D1 ) Compression of the hydrocarbon crude product gas stream C, wherein a propylene, C4, C5 and C6 +-a liquid hydrocarbon stream D11 containing hydrocarbons and a gaseous hydrocarbon stream D12 containing ethane, ethene and propylene are obtained; D2) separating water from the liquid hydrocarbon stream D11 by phase separation, thereby obtaining a liquid hydrocarbon stream D21; D3) Separation of a propylene-containing stream D31 from the liquid hydrocarbon stream D21, wherein a C4, C5 and C6 + -hydrocarbons-containing stream D32 is obtained; or separation of a stream D31 containing propylene and C4 hydrocarbons, wherein a C4, C5 and C6 + -hydrocarbon-containing stream D32 is obtained; D4) Separation of a C6 + -hydrocarbon-containing by-product stream D41 from the C4, C5 and C6 +-hydrocarbon-containing stream D32, obtaining a stream D42 containing C4, C5 and Cß hydrocarbons; optionally, stream D41 contains aromatic Cß hydrocarbons and stream D42 contains aliphatic Cß hydrocarbons; D5) separating a propylene-containing stream D51 from the ethane, ethene and propylene-containing gaseous hydrocarbon stream D12, whereby a stream D52 containing ethane and ethene is obtained; D6) Separating a butene-containing stream D61 from the C4, C5, and Cß hydrocarbon-containing stream D42, to obtain a C5 and Cß hydrocarbon-containing stream D62; and / or separating a propylene-containing stream D63 from the stream D31, to obtain a butene-containing stream D64; D7) Obtaining at least one recycle stream R from one or more of the streams selected from the C4, C5 and Cß hydrocarbon-containing stream D42, the C5 and Cß hydrocarbon-containing stream D62, the propylene-containing stream D31, the propylene-containing stream D51, the propylene-containing stream D63, the butene-containing stream D61, the butene-containing stream D64 and the ethane- and ethene-containing stream D52.