초록 ▼

A process and apparatus are provided for the present invention relates to a process for upgrading tar-containing effluent from a steam cracker furnace that comprises: a) contacting a steam cracker tar-containing effluent with steam and for a time, sufficient to convert at least a portion of the stea

A process and apparatus are provided for the present invention relates to a process for upgrading tar-containing effluent from a steam cracker furnace that comprises: a) contacting a steam cracker tar-containing effluent with steam and for a time, sufficient to convert at least a portion of the steam cracker tar to a mixture comprising lower boiling molecules and the steam cracker tar-containing effluent; and b) separating the mixture from step a) into i) at least one tar-lean product; and ii) a tar-rich product having a final boiling above the final boiling point of the at least one tar-lean product. Step a) can includes at least one of: 1) contacting said steam cracker tar-containing effluent with steam added to the effluent in a transfer line downstream of a steam cracker furnace comprising a quench inlet, with the steam added through or downstream of the quench inlet; 2) contacting the steam cracker tar-containing effluent with steam under heat soaking conditions in a heat soaking vessel to which the steam is added; and 3) contacting the steam cracker tar-containing effluent with steam under visbreaking conditions in a visbreaker. The steam treated tar can be separated into higher value gas oil, fuel oil and tar streams.

대표청구항 ▼

1. A process for upgrading tar-containing effluent from a steam cracker furnace comprising: a) feeding a hydrocarbon feedstock having a final boiling point above 260° C. to a steam cracking furnace containing a radiant section outlet producing a steam cracker tar-containing effluent;b) adding steam

1. A process for upgrading tar-containing effluent from a steam cracker furnace comprising: a) feeding a hydrocarbon feedstock having a final boiling point above 260° C. to a steam cracking furnace containing a radiant section outlet producing a steam cracker tar-containing effluent;b) adding steam to at least a portion of said steam cracker tar-containing effluent while the tar-containing effluent is at a temperature of from 300° C. to 850° C. to form a steam-effluent mixture; andc) separating the steam-effluent mixture into i) at least one tar-lean product containing a first tar; and ii) a tar-rich product containing a second tar, the tar-rich product having a final boiling point above the final boiling point of the at least one tar-lean product. 2. The process of claim 1, wherein the asphaltene concentration in the second tar is no greater than a comparative asphaltene concentration in a steam cracker tar within a steam cracker tar-containing effluent without said step b) addition of steam. 3. The process of claim 1, wherein said steam is added in step b) between the radiant section furnace outlet and a primary fractionator. 4. The process of claim 1, wherein said steam-effluent mixture of step b) is processed under heat soaking conditions in a heat soaking process. 5. The process of claim 4, wherein the heat soaking conditions include temperatures of from 300° to 600° C., total pressures no greater than 1138 kPa, and heat soaking times ranging from 0.1 to 100 hours. 6. The process of claim 1, wherein at least a portion of said steam-effluent mixture of step b) is visbroken under visbreaking conditions in a visbreaking process. 7. The process of claim 1, wherein the step b) of adding steam to at least a portion of a steam cracker tar-containing effluent comprises adding at steam in an amount of water to hydrocarbon effluent ratio of at least 1:1 not including the amount of steam or water added to the feedstock prior to cracking the feedstock in the radiant section. 8. The process of claim 1, wherein step b) further comprises recovering at least a portion of said steam cracker tar-containing effluent as primary fractionator bottoms and said steam of step b) is added to said primary fractionator bottoms to form said steam-effluent mixture, wherein said steam-effluent mixture is further processed in at least one of a heat soaking process and a visbreaking process. 9. The process of claim 8, thereafter conducting step c), wherein said at least one tar-lean product comprises at least one of a low boiling steam cracker gas oil stream and a medium boiling stream of low sulfur fuel oil, and said tar-rich product comprises a high boiling stream. 10. The process of claim 9, which further comprises at least one of i) adding at least a portion of the steam cracker gas oil stream to the high boiling stream to provide a fluxed tar stream and ii) directing at least a portion of the fluxed tar stream to a partial oxidation reactor. 11. The process of claim 1, further comprising recovering at least a portion of said steam cracker tar-containing effluent as tar knock-out drum bottoms and said steam of step b) is added to said tar knock-out bottoms forming said steam-effluent mixture, wherein said steam-effluent mixture is further processed in at least one of a heat soaking process and a visbreaking process. 12. The process of claim 1, further comprising: 1) before adding steam according to step b), separating said steam cracker tar-containing effluent into i) at least one tar-lean product; and ii) a tar-rich product, the tar-rich product having a final boiling point above the final boiling point of the at least one tar-lean product; and2) thereafter, adding steam according to step b) to said tar-rich product to from said steam-effluent mixture; and3) separating said steam-effluent mixture according to step c). 13. The process of claim 1, wherein said steam is added to said steam cracker tar-containing effluent in at least one of 1) upstream of a tar knockout drum, 2) within said tar knockout drum, and 3) downstream of a tar knockout drum bottoms outlet for conveying a portion of said steam cracker tar-containing effluent from said tar knockout drum. 14. The process of claim 13, thereafter conducting step c) using at least one of said tar knockout drum and a primary fractionator, wherein said at least one tar-lean product comprises at least one of a low boiling steam cracker gas oil stream and a medium boiling stream of low sulfur fuel oil, and said tar-rich product comprises a high boiling stream. 15. The process of claim 14, further comprising adding at least a portion of said steam cracked gas oil stream to said high boiling stream. 16. The process of claim 13, further comprising directing an overhead vapor stream from the tar knockout drum to a primary fractionator which provides a C4-overhead stream, a steam cracked naphtha side stream, a steam cracked gas oil side stream, and a quench oil bottoms stream. 17. The process of claim 16, further comprising recovering olefin products from at least a portion of said steam cracker tar-containing effluent. 18. The process of claim 16, further comprising adding at least a portion of the steam cracked gas oil side stream to a tar knockout drum bottoms stream. 19. The process of claim 1 wherein step b) consists of 1) contacting the steam cracker tar-containing effluent in the transfer line downstream of a steam cracker furnace, with steam added to the transfer line at or downstream of a quench oil inlet. 20. A process for upgrading tar-containing effluent from a steam cracker furnace fed with hydrocarbon feed having a final boiling point above 260° C. that comprises: a) directly contacting a steam cracker tar-containing effluent with steam and for a time, sufficient to convert at least a portion of the steam cracker tar to a mixture comprising lower boiling molecules and the steam cracker tar-containing effluent; andb) separating the mixture from step a) into i) at least one tar-lean product; and ii) a tar-rich product having a final boiling above the final boiling point of the at least one tar-lean product;wherein step a) includes at least one of:1) contacting the steam cracker tar-containing effluent with steam under heat soaking conditions in a heat soaking vessel to which the steam is added; and2) contacting the steam cracker tar-containing effluent with steam under visbreaking conditions in a visbreaker.