Process for starting up and shutting down a plant for removing isobutene from a C4-hydrocarbon mixture
AssigneeBASF SE
InventorsHans-Guenter Wagner, Suman Thotla, Gerrit Waters, Michael Huebner, Markus Neudert, Randolph Hugo, Thomas Roussiere
Life of this patent
Estimating the term…
Abstract
The invention relates to a process for starting up a plant for removing isobutene from an isobutene-containing C4-hydrocarbon mixture, the plant comprising an etherification unit containing moist acidic ion exchange resin, a first distillation unit, an ether cleavage unit, and a second distillation unit. The invention further relates to a process for shutting down the plant from a stationary operation mode.
Claims13
A process for starting up a plant for removing isobutene from an isobutene-containing C4-hydrocarbon mixture, the plant comprising an etherification unit containing moist acidic ion exchange resin, a first distillation unit, an ether cleavage unit, and a second distillation unit, the process comprising
- (a) filling the etherification unit with isobutanol;
- (b) filling the first distillation unit with C4-hydrocarbon and/or isobutanol, and operating the first distillation unit with total reflux;
- (c) filling the second distillation unit with C4-hydrocarbon and/or isobutanol, and operating the second distillation unit with total reflux;
- (d) withdrawing a bottom product of the second distillation unit, removing water from the bottom product and directing the bottom product to the etherification unit;
- (e) directing a discharge of the etherification unit to the first distillation unit;
- (f) directing a bottom product of the first distillation unit to the second distillation unit while bypassing the ether cleavage unit;
- (g) after the bottom product of the second distillation unit is essentially free of water, providing a flow of isobutene-containing C4-hydrocarbon mixture into the etherification unit and reacting the isobutene-containing C4-hydrocarbon mixture with isobutanol to form a mixture of IBTBE and unconverted hydrocarbons;
- (h) directing the mixture of IBTBE, unconverted hydrocarbons and unreacted isobutanol from the etherification unit to the first distillation unit and distilling the mixture to obtain a top product comprising the unconverted hydrocarbons, and a bottom product comprising IBTBE and unreacted isobutanol;
- (i) after IBTBE in the bottom product of the first distillation unit has reached a predetermined concentration, directing the bottom product of the first distillation unit to the ether cleavage unit to decompose the IBTBE to obtain isobutene and isobutanol;
- (j) directing the mixture of isobutene and isobutanol produced in step (i) to the second distillation unit and distilling the mixture of isobutene and isobutanol to obtain a top product comprising isobutene, and a bottom product comprising isobutanol and;
- (k) recycling the bottom product obtained in step (j) at least partially to the etherification unit.
A process for shutting down a plant for removing isobutene from an isobutene-containing C4-hydrocarbon mixture,
- wherein stationary operation of the plant comprises
- (a) reacting an isobutene-containing C4-hydrocarbon mixture with isobutanol in the presence of an acidic ion exchange resin in an etherification unit to form a mixture of IBTBE and unconverted hydrocarbons;
- (b) distilling the reaction mixture in a first distillation unit to obtain a top product comprising the unconverted hydrocarbons, and a bottom product comprising IBTBE;
- (c) feeding the bottom product to a ether cleavage unit to decompose the IBTBE to obtain isobutene and isobutanol;
- (d) distilling the mixture of isobutene and isobutanol produced in step (c) in a second distillation unit to obtain a top product comprising isobutene, and a bottom product comprising isobutanol;
- and
- (e) recycling the bottom product of step (d) to step (a);
- the shutting down process comprising
- aa) taking the ether cleavage unit out of service and purging the ether cleavage unit with an inert gas;
- while the etherification unit, the first distillation unit and the second distillation unit stay in operation;
- bb) stopping the flow of isobutene-containing C4-hydrocarbon mixture into the etherification unit;
- cc) taking the etherification unit out of service;
- dd) operating the first distillation unit and the second distillation unit in total reflux mode;
- and
- ee) stopping the first distillation unit and the second distillation unit.
Dependencies are inferred from the claim text.