Methanol to olefin (MTO) process
A process for producing an olefin stream, said process comprising passing a feedstock stream comprising oxygenates over catalyst comprises a zeolite with a framework having a 10-ring pore structure, in which said 10-ring pore structure comprises a unidimensional (1-D) pore structure, such as *MRE, at a pressure of 1-25 bar and a temperature of 240-360° C. The olefin stream may be converted to jet fuel, particularly sustainable aviation fuel (SAF) by further oligomerization and hydrogenation.
1 . A process for producing an olefin stream, said process comprising:
passing a feedstock stream comprising oxygenates over a catalyst active in the conversion of oxygenates, in which the catalyst comprises a zeolite with a framework having a 10-ring pore structure that is a unidimensional (1-D) pore structure, at a pressure of 1-25 bar and a temperature of 240-360° C. to produce an effluent stream comprising olefins and water; and
removing water from the effluent stream to obtain the olefin stream,
wherein said 1-D pore structure is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof,
wherein the feedstock stream comprises a diluent and methanol, wherein a methanol concentration in the feedstock stream is 2-20 vol. %,
wherein the olefin stream is essentially free of aromatics by comprising less than 5 wt % aromatics, wherein the olefin stream comprises 50 wt % or greater of C3-C8 olefins and 1 wt % or less of ethylene, and
wherein the process further comprises recycling a portion of an olefin-containing stream to the feedstock stream.
2 . The process according to claim 1 , wherein the catalyst comprises a binder selected from the group of refractory oxides and clays.
3 . The process according to claim 2 , wherein the catalyst comprises 30-90 wt % zeolite, and wherein the binder comprises an alumina component.
4 . The process according to claim 3 , wherein the catalyst contains 50-80 wt % zeolite with the binder.
5 . The process according to claim 1 , wherein the zeolite has a silica-to-alumina ratio (SAR) of up to 240.
6 . The process according to claim 1 , wherein said portion of the olefin-containing stream is a stream comprising C2-C3 olefins or a C3 olefin stream which is withdrawn from said olefin stream.
7 . The process according to claim 1 , wherein the feedstock stream comprising oxygenates is derived from one or more oxygenates taken from the group consisting of triglycerides, fatty acids, resin acids, ketones, aldehydes or alcohols or ethers, where said oxygenates originate from one or more of a biological source, a gasification process, a pyrolysis process, Fischer-Tropsch synthesis, or methanol-based synthesis.
8 . The process according to claim 1 , comprising: using a first reactor set including a single reactor or several reactors, for a partial or full conversion of the oxygenates.
9 . The process according to claim 8 , further comprising using a second reactor set including a single reactor or several reactors, for further conversion of unconverted oxygenates, and a phase separation stage in between the first reactor set and the second reactor set.
10 . The process according to claim 9 , comprising:
passing the feedstock stream comprising oxygenates through the first reactor set under conditions for partly converting the oxygenates, thereby forming a raw olefin stream comprising unconverted oxygenates and C2-C8 olefins;
passing the raw olefin stream through said phase separation stage, for producing:
a first olefin stream comprising 50 wt % or greater of C2 olefins;
a separated oxygenate stream comprising unconverted oxygenates;
a second olefin stream comprising 50 wt % or greater of C3-C8 olefins;
combining the first olefin stream with the separated oxygenate stream comprising the unconverted oxygenates, thereby forming a combined stream comprising lower olefins and the unconverted oxygenates;
passing the resulting combined stream comprising lower olefins and the unconverted oxygenates through the second reactor set under conditions for fully converting the unconverted oxygenates and the lower olefins, into a third olefin stream comprising 50 wt % or greater of C3-C8 olefins; and
combining the second olefin stream with the third olefin stream, thereby forming said effluent stream.
11 . The process according to claim 1 , further comprising:
passing at least a portion of the olefin stream, through an oligomerization step over an oligomerization catalyst, and optionally subsequently conducting a separation step, for thereby producing an oligomerized stream.
12 . The process according to claim 11 , further comprising:
passing at least a portion of the oligomerized stream through a hydrogenation step over a hydrogenation catalyst, and optionally subsequently conducting a separation step, for thereby producing a hydrocarbon stream comprising hydrocarbons boiling in the jet fuel range.
13 . The process according to claim 11 , wherein the oligomerization step and hydrogenation step are combined in a single hydro-oligomerization step, wherein the oligomerization step is dimerization, optionally also trimerization, by the hydro-oligomerization step being conducted by reacting, under the presence of hydrogen, the olefin stream, over a catalyst comprising a hydrogenation metal.
14 . The process according to claim 1 , wherein the olefin stream is passed directly to the oligomerization step.
15 . The process according to claim 1 , wherein the olefin stream comprises at least 70 wt % C3-C8 olefins.
16 . The process according to claim 15 , wherein the olefin stream further comprises:
1 wt % or less of aromatics.
17 . The process according to claim 15 , wherein the temperature is 320-360° C.
18 . The process according to claim 1 , wherein the distribution of olefins in the olefin stream is at least 67 wt % C4-C7 olefins.
19 . A process for producing an olefin stream, said process comprising:
passing a feedstock stream comprising oxygenates over a catalyst active in the conversion of oxygenates, in which the catalyst comprises a zeolite with a framework having a 10-ring pore structure that is a unidimensional (1-D) pore structure, at a pressure of 1-25 bar and a temperature of 240-360° C. to produce an effluent stream comprising olefins and water; and
removing water from the effluent stream to obtain the olefin stream; and
wherein said 1-D pore structure is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof, and
wherein the feedstock stream comprises a diluent and methanol, wherein a methanol concentration in the feedstock stream is 2-20 vol. %, and
wherein the process further comprises separating from the olefin stream an isoparaffin stream.
20 . The process according to claim 19 , further comprising:
passing at least a portion of the olefin stream, after separating said isoparaffin stream, through an oligomerization step over an oligomerization catalyst, and optionally subsequently conducting a separation step, for thereby producing an oligomerized stream.
21 . The process according to claim 19 , wherein the entire olefin stream after separating said isoparaffin stream is passed directly to the oligomerization step.
22 . A process for producing an olefin stream, said process comprising:
passing a feedstock stream comprising oxygenates over a catalyst active in the conversion of oxygenates, in which the catalyst comprises a zeolite with a framework having a 10-ring pore structure that is a unidimensional (1-D) pore structure, at a pressure of 1-25 bar, and a temperature of 240-360° C. to produce an effluent stream comprising olefins and water; and
removing water from the effluent stream to obtain the olefin stream,
wherein said 1-D pore structure is any of *MRE (ZSM-48), MTT (ZSM-23), TON (ZSM-22), or combinations thereof,
wherein the olefin stream is essentially free of aromatics by comprising less than 5 wt % aromatics, wherein the olefin stream comprises 50 wt % or greater of C3-C8 olefins and 1 wt % or less of ethylene, and
wherein the process further comprises recycling a portion of an olefin-containing stream to the feedstock stream.
23 . The process according to claim 22 , wherein the oxygenates are selected from methanol (MeOH), dimethyl ether (DME), or combinations thereof.
24 . The process according to claim 22 , wherein the feedstock stream comprises a diluent and methanol, wherein a methanol concentration in the feedstock stream is 5-10 vol. %.