Process for production of ethylbenzene frome dilute ethylene streams
AssigneeAmoco Corporation
InventorDae K. Kim
Life of this patent
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Abstract
The present invention relates to a process for the production of ethylbenzene from dilute ethylene streams, especially from mixtures of ethane and ethylene where such mixture is the offgas from a refinery operation, such as a fluid catalytic cracking (FCC) operation and wherein the unreacted ethane from the alkylation reactor is dehydrogenated to produce ethylene which is recycled into the original dilute ethylene stream.
Claims34
A process for producing ethylbenzene from an ethylene stream comprising a dilute ethylene stream from a fluid catalytic cracking (FCC) operation and an effluent stream from dehydrogenation of ethane in a thermal steam cracker, said ethylene stream containing a light ends component comprising hydrogen and methane and a heavy cut comprising ethylene, ethane, and C.sub.3 + hydrocarbons, which process comprises:
- (a) separating the light ends from the heavy cut by passing the dilute ethylene stream through a light ends removal unit and recovering an effluent stream comprising said light ends and another effluent stream containing said heavy cut;
- (b) separating the C.sub.3 + hydrocarbons from the heavy cut by passing the effluent stream containing the heavy cut from the light ends removal unit through a heavy olefins removal unit under pressure and temperature conditions sufficient to separate substantially all of the C.sub.3 + hydrocarbons and recovering an enriched ethylene effluent stream comprising ethylene and ethane;
- (c) contacting the enriched ethylene effluent stream from the heavy olefins removal unit with benzene in the presence of an alkylation catalyst selected from aluminum chloride catalysts and zeolite catalysts in a reaction zone under reaction conditions wherein the benzene is alkylated by substantially all of the ethylene to form ethylbenzene and recovering the ethylbenzene;
- (d) recovering from the reaction zone an alkylation reactor effluent stream comprising ethane;
- (e) dehydrogenating at least a portion of the ethane in said alkylation reactor effluent stream in a thermal steam cracker to form an effluent stream containing ethylene;
- and
- (f) combining the ethylene-containing effluent stream thus formed with the dilute ethylene stream from the fluid catalytic cracking (FCC) operation going to the light ends removal unit thereby enriching the ethylene content of the dilute ethylene stream from the fluid catalytic cracking (FCC) operation and recycling to the reaction zone the ethylene formed by dehydrogenation.
A process for producing ethylbenzene from an ethylene stream comprising a dilute ethylene stream from FCC offgas and an effluent stream from dehydrogenation of ethane in a thermal steam cracker, said ethylene stream containing a light ends component comprising hydrogen and methane and a heavy cut comprising ethylene, ethane, and C.sub.3 + hydrocarbons, which process comprises:
- (a) separating the light ends from the heavy cut by passing the dilute ethylene stream from FCC offgas to a pressure swing adsorption unit and contacting it with an adsorbent selective for the adsorption of said heavy cut under a pressure and temperature at which at least a portion of the heavy cut is adsorbed and recovering an effluent stream comprising said light ends and then desorbing said heavy cut from the adsorbent under reduced pressure and recovering another effluent stream containing said heavy cut;
- (b) contacting the effluent stream containing the heavy cut with a deethanizer under a pressure and temperature sufficient to separate substantially all of the C.sub.3 + hydrocarbons and recovering a dilute ethylene effluent stream comprising ethylene and ethane;
- (c) contacting the dilute ethylene effluent stream from the deethanizer with benzene in the presence of an alkylation catalyst selected from aluminum chloride catalysts and zeolite catalysts in a reaction zone under reaction conditions wherein the benzene is alkylated by substantially all of the ethylene to form ethylbenzene and recovering the ethylbenzene;
- (d) recovering from the reaction zone an alkylation reactor effluent stream comprising ethane;
- (e) dehydrogenating at least a portion of the ethane in said alkylation reactor effluent stream in a thermal steam cracker to form an effluent stream containing ethylene;
- and
- (f) combining the ethylene-containing effluent stream thus formed with the dilute ethylene stream from FCC offgas going to the pressure swing adsorption unit thereby enriching the ethylene content of the FCC offgas stream and recycling to the reaction zone the ethylene formed by dehydrogenation.
A process for producing ethylbenzene from an ethylene stream comprising a dilute ethylene stream from FCC offgas and an effluent stream from dehydrogenation of ethane in a thermal steam cracker, said ethylene stream comprising hydrogen, methane, ethane, ethylene, and C.sub.3 + hydrocarbons, said process comprising:
- (a) subjecting said dilute ethylene stream to a cyclic adsorption process in at least one bed of adsorbent which selectively adsorbs ethylene, ethane, and C.sub.3 + hydrocarbons, thereby producing a non-adsorbed hydrogen and methane component and an adsorbed ethylene, ethane, and C.sub.3 + hydrocarbon component;
- (b) removing the non-adsorbed hydrogen and methane component and optionally separating and recovering the hydrogen;
- (c) desorbing the ethylene, ethane, and C.sub.3 + hydrocarbon component and contacting it with a deethanizer under a pressure and temperature sufficient to separate substantially all of the C.sub.3 +hydrocarbons and recovering a dilute ethylene effluent stream comprising ethylene and ethane;
- (d) contacting the dilute ethylene effluent stream from the deethanizer with benzene in the presence of an alkylation catalyst selected from aluminum chloride catalysts and zeolite catalysts in a reaction zone under reaction conditions wherein the benzene is alkylated by substantially all of the ethylene to form ethylbenzene and recovering the ethylbenzene;
- (e) recovering from the reaction zone an alkylation reactor effluent stream comprising ethane;
- (f) dehydrogenating at least a portion of the ethane in said alkylation reactor effluent stream in a thermal steam cracker to form an effluent stream containing ethylene;
- and
- (g) combining the ethylene-containing effluent stream thus formed with the dilute ethylene stream from FCC offgas going to the bed of adsorbent in step (a) thereby enriching the ethylene content of the FCC offgas stream and recycling to the reaction zone the ethylene formed by dehydrogenation.
Dependencies are inferred from the claim text.