Pyrolysis Tar Upgrading

Abstract

Processes and apparatus for preparing a liquid hydrocarbon product are provided. In one embodiment, a process for prepreparing a liquid hydrocarbon product includes thermally-treating a tar to produce a first tar composition and blending the tar composition with a utility fluid to form a tar-fluid mixture. The process includes separating the tar-fluid mixture to form a first lower-density portion and a first higher-density portion containing solids. The process further includes thermally-treating the first higher-density portion to form a thermally-treated first higher-density portion to convert at least a portion of the solids to liquid.

1 . A tar upgrading process, comprising:
 thermally-treating a tar in a first thermal treatment to produce a tar composition;   separating from at least a portion of the tar composition a first lower-density portion and a first higher-density portion, wherein the first higher density portion comprises solids in an amount A 1  wt. % based on the weight of the first higher density portion;   conducting away an upgraded pyrolysis tar composition comprising at least a portion of the first lower-density portion;   thermally-treating at least a portion of the first higher-density portion in a second thermal treatment to form a thermally-treated first higher-density portion, wherein (i) the thermally-treated first higher density portion comprises solids in an amount A 2  wt. % based on the weight of thermally-treated first higher density portion and (ii) A 2 <A 1 ;   separating from at least a portion of the thermally-treated first higher-density portion a second lower-density portion and second higher-density portion; and   adding at least a portion of the second lower-density portion to one or more of (i) the pyrolysis tar before and/or during the first thermal treatment, (ii) the pyrolysis tar composition, (iii) the first higher-density portion, and (iv) the first lower-density portion.   
     
     
         2 . The process of  claim 1 , further comprising adding a fluid to the tar composition, wherein ≥90 wt. % of the added fluid is transferred to the first lower-density portion. 
     
     
         3 . The process of  claim 1 , further comprising adding a diluent to the first higher-density portion, and wherein ≥90 wt. % of the added diluent resides in the second lower-density portion. 
     
     
         4 . The process of  claim 1 , wherein the first thermal treatment includes maintaining the tar at a temperature ≤350° C. for a time in the range of from 10 minutes to 60 minutes. 
     
     
         5 . The process of  claim 1 , wherein the first thermal treatment includes maintaining the tar at a temperature in the in the range of from 150° C. to 300° C. for a time in the range of from 15 minutes to 30 minutes. 
     
     
         6 . The process of  claim 1 , wherein (i) the second thermal treatment includes maintaining the first higher-density portion at a temperature in the range of from 220° C. to 500° C. for a time in the range of from 10 minutes to 100 minutes and (ii) A 2 ≤0.8*A 1 . 
     
     
         7 . The process of  claim 1 , wherein the second thermal treatment includes maintaining the first higher-density portion at a temperature in the range of from 250° C. to 400° C. for a time in the range of from 20 minutes to 90 minutes. 
     
     
         8 . The process of  claim 1 , wherein A 2  is in the range of from 10% of A 1  to 40% of A 1 . 
     
     
         9 . The process of  claim 1 , wherein the tar is a pyrolysis tar comprising steam cracker tar. 
     
     
         10 . The process of  claim 1 , wherein the tar is a steam cracker tar produced by steam cracking a steam cracker feed that includes ≥10 wt. % based on the weight of the steam cracker feed of material that is solid-phase or liquid-phase at 25° C. and a pressure of 1 bar absolute. 
     
     
         11 . The process of  claim 1 , wherein:
 (i) the tar is a steam cracking tar produced by steam cracking a hydrocarbon feed comprising ≥1 wt. % of hydrocarbon having a normal boiling point ≥566° C. based on the weight of the steam cracker feed;   (ii) the stream cracker includes a convection section and a radiant section;   (iii) the hydrocarbon feed is preheated in the convection section and combined with steam to produce a steam cracker feed;   (iv) a primarily vapor-phase stream and a primarily non-vapor-phase stream are separated from at least a portion of the steam cracker feed, wherein ≥50 wt. % of any hydrocarbon having a normal boiling point ≥566° C. in the hydrocarbon-containing feed is transferred to the non-vapor-phase stream;   (v) at least a portion of the primarily vapor-phase stream is conducted into an inlet of at least one radiant coil located in the radiant section for cracking under steam cracking conditions, wherein the radiant coil includes the inlet and an outlet, and the steam cracking conditions include:
 a temperature at the radiant coil outlet in the range of from about 760° C. to about 1200° C., 
 a steam cracking pressure at the radiant coil outlet in the range of from about 1 bar(absolute) to about 10 bar(absolute), and 
 a steam cracking residence time in the radiant coil in the range of from about 0.1 seconds to about 2 seconds; 
   (vi) a steam cracker effluent is conducted away from the radiant section; and   (vii) separating at least the steam cracker tar from the steam cracker effluent.   
     
     
         12 . The process of  claim 11 , wherein the primarily vapor-phase stream and the primarily non-vapor-phase stream are separated from the steam cracker feed in a separation stage integrated with the convection section, and wherein the separated primarily vapor-phase stream is exposed to additional heating in the convection section before the cracking. 
     
     
         13 . The process of  claim 11 , wherein the temperature at the radiant coil outlet is in the range of from about 880° C. to about 1,200° C. 
     
     
         14 . The process of  claim 11 , wherein the temperature at the radiant coil outlet in in the range of from about 1,000° C. to about 1,200° C., and the steam cracking pressure is in the range of from about 6 bar(absolute) to about 10 bars(absolute). 
     
     
         15 . The process of  claim 11  wherein the steam cracking temperature is in the range of from about 760° C. to about 880° C., and the steam cracking pressure is in the range of from about 1 bar(absolute) to about 5 bars(absolute). 
     
     
         16 . The process of  claim 1 , wherein the tar composition further comprises material resulting from the first thermal treatment. 
     
     
         17 . The process of  claim 3 , further comprising grinding the first higher-density portion before and/or after adding the diluent. 
     
     
         18 . A steam cracker tar upgrading process comprising:
 steam cracking a hydrocarbon feed comprising heavy oil to form a steam cracker effluent comprising steam cracker tar;   separating at least a portion of the steam cracker tar from the steam cracker effluent;   thermally treating at least the separated steam cracker tar in a first thermal treatment to produce a steam cracker tar composition;   adding a first utility fluid and/or a first separation fluid to the steam cracker tar composition to produce a tar-fluid mixture;   separating from the tar-fluid mixture (i) a first lower-density portion comprising upgraded steam cracker tar and (ii) a first higher-density portion;   conducting away at least a portion of the first lower-density portion;   introducing a second utility fluid to the first higher-density portion to form a diluted first higher-density portion, wherein the diluted first higher density portion comprises solids in an amount A 1  wt. % based on the weight of the first higher density portion;   thermally-treating the diluted first higher-density portion in a second thermal treatment to form a thermally-treated first higher-density portion, wherein (i) the thermally-treated first higher density portion comprises solids in an amount A 2  wt. % based on the weight of thermally-treated first higher density portion and (ii) A 2 ≤0.8*A 1 ;   separating in a second separation at least a second lower-density portion and a second higher-density portion from the thermally-treated first higher-density portion; and   adding at least a portion of the second lower-density portion to one or more of (i) the steam cracker effluent, (ii) the steam cracker tar before and/or during the first thermal treatment, (iii) the steam cracker tar composition, (iv) the tar-fluid mixture before and/or during the separation of the first higher-density portion and the first lower-density portion, (v) the first higher-density portion, and (vi) the first lower-density portion.   
     
     
         19 . The process of  claim 18 , wherein
 (i) steam cracking the heavy oil is performed at a temperature of from about 760° C. to about 880° C., a pressure of from about 1 bar(absolute) to about 5 bars(absolute), and a residence time of from about 0.1 seconds to about 2 seconds;   (ii) the first thermal treatment includes maintaining the steam cracker tar at a temperature in the in the range of from 150° C. to 300° C. for a time in the range of from 15 minutes to 30 minutes; and   (iii) the second thermal treatment includes maintaining the diluted first higher-density portion at a temperature in the range of from 300° C. to 400° C. for a time in the range of from 30 minutes to 60 minutes.   
     
     
         20 . The process of  claim 18 , the tar-fluid mixture comprises the steam cracker tar composition in an amount in the range of about 40 wt. % to about 80 wt. % of, based on the weight of the tar-fluid mixture. 
     
     
         21 . The process of  claim 18 , further comprising grinding the first higher-density portion before and/or after introducing the second utility fluid. 
     
     
         22 . The process of  claim 18 , further comprising (i) hydroprocessing at least a portion of the first lower-density portion and (ii) conducting away at least a portion of the second higher-density portion. 
     
     
         23 . The process of  claim 18 , wherein (i) the first and/or second thermal treatments include heat soaking in at least one soaker drum, and/or (ii) the first and/or second separations include centrifuging and/or filtration. 
     
     
         24 . A steam cracker tar upgrading process comprising:
 steam cracking a hydrocarbon feed comprising heavy oil at a temperature of from about 760° C. to about 880° C., a pressure of from about 1 bar(absolute) to about 5 bars(absolute), and a residence time of from about 0.1 seconds to about 2 seconds to form a steam cracker effluent comprising a steam cracker tar;   separating at least a portion of the steam cracker tar from the steam cracker effluent;   thermally treating at least the separated steam cracker tar in a first thermal treatment by maintaining the steam cracker tar at a temperature of from 150° C. to 300° C. for a time of from 15 minutes to 30 minutes to produce a steam cracker tar composition comprising polymeric particulates formed during or as a result of the first thermal treatment;   adding a first utility fluid and/or a first separation fluid to the steam cracker tar composition to produce a tar-fluid mixture;   separating from the tar-fluid mixture (i) a first lower-density portion comprising upgraded steam cracker tar and (ii) a first higher-density portion comprising the polymeric particulates, wherein the first higher density portion comprises the polymeric particulates in an amount A 1  wt. % based on the weight of the first higher density portion;   conducting away at least a portion of the first lower-density portion;   introducing a second utility fluid to the first higher-density portion to form a diluted first higher-density portion;   thermally-treating the diluted first higher-density portion in a second thermal treatment by maintaining the diluted first higher-density portion at a temperature in the range of from 300° C. to 400° C. for a time in the range of from 30 minutes to 60 minutes to form a thermally-treated first higher density portion wherein (i) the thermally-treated first higher density portion comprises conversion products of lesser density as compared to the polymeric particulates, (ii) the thermally-treated first higher density portion comprises polymeric particulates in an amount A 2  wt. % based on the weight of thermally-treated first higher density portion and (iii) A 2 ≤0.8*A 1 ;   separating in a second separation at least a second lower-density portion and a second higher-density portion from the thermally-treated first higher-density portion, the second lower-density portion comprising the conversion products of lesser density; and   adding at least a portion of the second lower-density portion to one or more of (i) the steam cracker effluent, (ii) the steam cracker tar before and/or during the first thermal treatment, (iii) the steam cracker tar composition, (iv) the tar-fluid mixture before and/or during the separation of the first higher-density portion and the first lower-density portion, (v) the first higher-density portion, and (vi) the first lower-density portion.   
     
     
         25 .- 30 . (canceled)