Process for producing BTX from a mixed hydrocarbon source using pyrolysis
The present invention relates to a process for producing BTX comprising pyrolysis, aromatic ring opening and BTX recovery. Furthermore, the present invention relates to a process installation to convert a pyrolysis feedstream into BTX comprising a pyrolysis unit, an aromatic ring opening unit and a BTX recovery unit.
1. A process for producing BTX comprising:
(a) subjecting a pyrolysis feedstream comprising hydrocarbons to pyrolysis to produce pyrolysis gasoline and C9+ hydrocarbons;
(b) subjecting C9+ hydrocarbons to aromatic ring opening to produce BTX; and
(c) recovering BTX from pyrolysis gasoline,
wherein the pyrolysis further produces LPG and wherein said LPG produced by pyrolysis is subjected to aromatization to produce BTX.
2. The process according to claim 1 , wherein the aromatic ring opening further produces light-distillate and wherein the BTX is recovered from said light-distillate.
3. The process according to claim 1 , wherein the BTX is recovered from the pyrolysis gasoline and/or from the light-distillate by subjecting said pyrolysis gasoline and/or light-distillate to hydrocracking.
4. The process according to claim 1 , wherein the aromatic ring opening and the hydrocracking further produce LPG and wherein said LPG is subjected to aromatization to produce BTX.
5. The process according to claim 3 , wherein the aromatic ring opening further produces light-distillate and wherein the BTX is recovered from said light-distillate.
6. The process according to claim 5 , wherein propylene and/or butylenes are separated from the LPG produced by pyrolysis before subjecting to aromatization.
7. The process according to claim 1 , wherein said pyrolysis comprises heating the pyrolysis feedstream in the presence of steam to a temperature of 750-900° C. with residence time of 50-1000 milliseconds at a pressure of atmospheric to 175 kPa gauge.
8. The process according to claim 3 , wherein said hydrocracking comprises contacting the pyrolysis gasoline and the light-distillate in the presence of hydrogen with a hydrocracking catalyst under hydrocracking conditions, wherein
the hydrocracking catalyst comprises 0.1-1 wt-% hydrogenation metal in relation to the total catalyst weight and a zeolite having a pore size of 5-8 Å and a silica (SiO 2 ) to alumina (Al 2 O 3 ) molar ratio of 5-200 and wherein
the hydrocracking conditions comprise a temperature of 400-580° C., a pressure of 300-5000 kPa gauge and a Weight Hourly Space Velocity (WHSV) of 0.1-20 h −1 .
9. The process according to claim 1 , wherein said aromatic ring opening comprises contacting the C9+ hydrocarbons in the presence of hydrogen with an aromatic ring opening catalyst under aromatic ring opening conditions, wherein the aromatic ring opening catalyst comprises a transition metal or metal sulphide component and a support and wherein the aromatic ring opening conditions comprise a temperature of 100-600° C., a pressure of 1-12 MPa.
10. The process according to claim 9 , wherein the aromatic ring opening catalyst comprises an aromatic hydrogenation catalyst comprising one or more elements selected from the group consisting of Ni, W and Mo on a refractory support; and a ring cleavage catalyst comprising a transition metal or metal sulphide component and a support and wherein the conditions for aromatic hydrogenation comprise a temperature of 100-500° C., a pressure of 2-10 MPa and the presence of 1-30 wt-% of hydrogen in relation to the hydrocarbon feedstock and wherein the ring cleavage comprises a temperature of 200-600° C., a pressure of 1-12 MPa and the presence of 1-20 wt-% of hydrogen in relation to the hydrocarbon feedstock.
11. The process according to claim 4 , wherein the aromatization comprises contacting the LPG with an aromatization catalyst under aromatization conditions, wherein
the aromatization catalyst comprises a zeolite selected from the group consisting of ZSM-5 and zeolite L, optionally further comprising one or more elements selected from the group consisting of Ga, Zn, Ge and Pt and wherein
the aromatization conditions comprise a temperature of 400-600° C., a pressure of 100-1000 kPa gauge and a Weight Hourly Space Velocity (WHSV) of 0.1-20 h −1 .
12. The process according to claim 4 , wherein
the LPG produced by hydrocracking and aromatic ring opening is subjected to a first aromatization that is optimized towards aromatization of paraffinic hydrocarbons, wherein said first aromatization comprises the aromatization conditions comprising a temperature of 400-600° C., a pressure of 100-1000 kPa gauge and a Weight Hourly Space Velocity (WHSV) of 0.1-7 h −1 ; and/or wherein
the LPG produced by pyrolysis is subjected to a second aromatization that is optimized towards aromatization of olefinic hydrocarbons, wherein said second aromatization comprises the aromatization conditions comprising a temperature of 400-600° C., a pressure of 100-1000 kPa gauge and a Weight Hourly Space Velocity (WHSV) of 1-20 h −1 .
13. The process according to claim 1 , wherein one or more of the group consisting of the pyrolysis, the hydrocracking and the aromatic ring opening, and optionally the aromatization, further produce methane and wherein said methane is used as fuel gas to provide process heat.
14. The process according to claim 1 , wherein the pyrolysis feedstream comprises naphtha.
15. The process according to claim 1 , wherein the pyrolysis and/or the aromatization further produce hydrogen and wherein said hydrogen is used in the hydrocracking and/or the aromatic ring opening.
16. The process according to claim 9 , wherein the support comprises one or more elements selected from the group consisting of Pd, Rh, Ru, Ir, Os, Cu, Co, Ni, Pt, Fe, Zn, Ga, In, Mo, W and V in metallic or metal sulphide form supported on an acidic solid.
17. The process according to claim 16 , wherein the support is selected from the group consisting of alumina, silica, alumina-silica and zeolites.
18. The process according to claim 14 , wherein the pyrolysis feedstream comprises paraffinic naphtha or straight run naphtha.
19. The process according to claim 2 , wherein the aromatic ring opening and the hydrocracking further produce LPG and wherein said LPG is subjected to aromatization to produce BTX.
20. The process according to claim 9 , wherein the aromatic ring opening and the hydrocracking further produce LPG and wherein said LPG is subjected to aromatization to produce BTX.