Crude petroleum oil processing method for crude distillation unit

Abstract

In methods for the Crude Distillation Unit, a desalted crude oil and water mixture is processed through a heating exchangers, cooling exchangers, and vapor-liquid phases separating vessels, fired furnace, superheated vapor steam, the liquid stream having a wide distillation boiling range and partially vaporized crude oil streams. These streams are processed in an atmospheric distillation column to generate the distillate products and long residue stream. The long residue generated from the ADC striping section is processed with steam in the separate vessel with plural trays or the new separation section with plural trays added to the existing ADC design. The methods result in simultaneous reduction in thermal energy, reduction in vacuum system load, opportunity to increase the crude throughput for a given diameter of ADC and eliminating need for a fired furnace for superheating the vapor stream to be used at bottom section of ADC.

We claim: 
     
         1 . A crude petroleum oil processing method for crude distillation unit (CDU), the method comprising:
 (a) heating the crude petroleum oil ( 1 ,  FIG.  3   ) in a Heat Exchanger Network- 1  (HEN 1 ,  FIG.  3   ) at from 110° C. to 140° C. and subjecting the heated crude to desalter ( 2 ,  FIG.  3   ) along with desalter water (DW,  FIG.  3   ) to obtain cold desalted crude (DCO);   (b) mixing cold desalted crude (DCO) with water (W) followed by heating in Heat Exchanger Network- 2  (HEN 2 ) at from 180° C. to 260° C. or DCO is first preheated using the HEN 2  at from 180° C. to 260° C. and then mixed with water in one of the heat exchanger used in HEN 2  to generate hot stream ( 3 ,  FIG.  3   );   (c) passing the hot stream ( 3 ,  FIG.  3   ) to pressure-reducing device- 1  (PRD- 1 ,  FIG.  3   ) and routing the partially vaporized crude oil to two phases separating vessel ( 4 ,  FIG.  3   ) having the plural trays and stripping media stream ( 5 S,  FIG.  3   );   (d) cooling the vapor stream ( 7 ) from the vessel ( 4 ) at from 180° C. to 210° C. using Heat Exchanger Network- 4  (HEN 4 ,  FIG.  3   ) and routing the cooled stream ( 7 A,  FIG.  3   ) to a two-phase separating vessel ( 7 B,  FIG.  3   );   (e) superheating hydrocarbon vapor stream ( 7 C,  FIG.  3   ) from the vessel ( 7 B,  FIG.  3   ) in Heat Exchanger Network- 5  (HEN 5 ,  FIG.  3   ) using the hot process streams and external heating sources;   (f) injecting the superheated hydrocarbon vapor stream ( 7 H,  FIG.  3   ) at either the bottom of the stripping section ( 10 ,  FIG.  3   ) of the atmospheric distillation column (ADC) ( 8 ,  FIG.  3   ) or a tray between the bottom tray and flash zone ( 9 ,  FIG.  3   ) of the ADC ( 8 ,  FIG.  3   );   (g) routing the liquid stream ( 7 D,  FIG.  3   ) from the vessel ( 7 B,  FIG.  3   ) to ADC at a single location or at different locations between HGO and Kerosene draw stages as  7 D 1 ,  7 D 2  and  7 D 3  streams;   (h) heating the liquid crude oil stream ( 5 ,  FIG.  3   ) obtained from the vessel ( 4 ,  FIG.  3   ) in the Heat Exchanger Network- 3  (HEN 3 ,  FIG.  3   ) and fed to a fired furnace (F 1 ,  FIG.  3   );   (i) routing of partially vaporized crude oil stream ( 6 ,  FIG.  3   ) obtained from F 1  to flash zone ( 9 ,  FIG.  3   ) of atmospheric distillation column ( 8 ,  FIG.  3   ) having the plurality of trays;   (j) fractionating the stream ( 7 H,  FIG.  3   ), stream ( 7 D,  FIG.  3   ) and stream ( 6 ,  FIG.  3   ) in the ADC ( 8 ) to generate the different distillate products, overhead vapor ( 15 ,  FIG.  3   ) and long residue stream ( 18 ,  FIG.  3   );   (k) cooling the overhead vapor ( 15 ,  FIG.  3   ) using a condenser (E- 1 ,  FIG.  3   ) and fed to three-phase separating vessel (V 1 ,  FIG.  3   ) to separate vapor ( 16 ,  FIG.  3   ), liquid (reflux), which is routed to ADC ( 8 ) and sour water (SW- 1 ,  FIG.  3   );   (l) routing the vapor stream ( 16 ) from VI to a two or three-phase separating vessel (V 2 ,  FIG.  3   ) after its cooling in a cooler (E- 2 ,  FIG.  3   ) at a temperature from 30° C. to 50° C. to separate unstabilized naphtha ( 17 ,  FIG.  3   ), sour water (SW- 2 ,  FIG.  3   ) and noncondensed gas (NCG) stream;   (m) subjecting the unstabilized naphtha ( 17 ,  FIG.  3   ) to the distillation column ( 15 ,  FIG.  3   ) to produce the LPG, Light Naphtha (LN) and noncondensed vapor stream (NCV- 1 ,  FIG.  3   );   (n) passing the heavy naphtha (HN) and kerosene, Light and Heavy Gas Oil (LGO and HGO) distillates from the different trays of ADC ( 8 ,  FIG.  3   ) to the reboiled side strippers ( 11 ,  FIG.  3   ), and steam stripers ( 12 ,  13  and  14 ,  FIG.  3   ), respectively to remove lighter hydrocarbon and to obtain heavy naphtha (HN) and kerosene, LGO and HGO distillate products;   (o) processing the long residue stream ( 18 ,  FIG.  3   ) and steam stream (SS 4 ,  FIG.  3   ) in a vessel ( 14 A,  FIG.  3   ) having plural trays;   (p) routing the vapor stream ( 18 A,  FIG.  3   ) from vessel ( 14 A,  FIG.  3   ) to the bottom of ADC ( 8 ,  FIG.  3   ) and liquid stream ( 18 B,  FIG.  3   ) from vessel ( 14 A,  FIG.  3   ) with furnace coil steam to a furnace (F 3 ,  FIG.  3   ); and   (q) processing the partially vaporized crude ( 19 ,  FIG.  3   ) by known method in a Vacuum Distillation Column (VDC,  FIG.  1   ) to obtain the vacuum distillates and residue products.   
     
     
         2 . The method according to  claim 1 , wherein the DCO and water mixture generated in (b) is heated in a Heat Exchanger Network (HEN  2 ) at a temperature from 180° C. to 260° C. 
     
     
         3 . The method according to  claim 1 , wherein the striping media ( 5 S) used in vessel ( 4 ) is steam or lighter hydrocarbons vapor stream having methane, ethane, propane, butane, pentane, and light naphtha components. 
     
     
         4 . The method according to  claim 1 , the vapor stream ( 7 C) from (e) is superheated preferably at from 270° C. to 340° C. in HEN 5  using process streams and/or high-pressure steam. 
     
     
         5 . The method according to  claim 1 , the liquid crude oil stream ( 5 ) obtained from the vessel ( 4 ) is heated in the Heat exchanger network- 3  (HEN 3 ) at a temperature from 270° C. to 330° C. and subsequently heated in a fired furnace (F 1 ) at a temperature from 350° C. to 400° C. 
     
     
         6 . The method according to  claim 1 , wherein overhead vapor ( 15 ) from (k) is cooled using a condenser (E- 1 ) at a temperature from 70° C. to 130° C. 
     
     
         7 . The method according to  claim 1 , wherein the liquid stream ( 18 B) mixed with furnace coil steam is heated in a furnace (F 3 ) to a temperature from 360° C. to 450° C. 
     
     
         8 . The method according to  claim 1 , the long residue stream ( 18 ,  FIG.  5   ) generated from the stripping section ( 10 ) of ADC ( 8 ,  FIG.  5   ) is fed to the top tray of the new separation section ( 10 A,  FIG.  5   ) of ADC ( 8 ) and steam (SS 4 ,  FIG.  5   ) is injected at the bottom tray of section ( 10 A,  FIG.  5   ) to generate the stream ( 18 B,  FIG.  5   ). 
     
     
         9 . A method for processing crude petroleum oil for a crude distillation unit, the method comprising:
 heating the crude petroleum oil ( 1 ,  FIG.  3   ) in Heat Exchanger Network- 1  (HEN 1 ,  FIG.  3   ) at a temperature from 110° C. to 140° C. and subjecting the heated crude to desalter ( 2 ,  FIG.  3   ) along with desalter water (DW,  FIG.  3   ) to obtain cold desalted crude (DCO);   mixing cold desalted crude (DCO) with water (W) followed by heating in Heat Exchanger Network- 2  (HEN 2 ) at a temperature from 180° C. to 260° C. or DCO is first preheated using the HEN 2  at a temperature from 180° C. to 260° C. and then mixed with water in one of the heat exchanger used in HEN 2  to generate hot stream ( 3 ,  FIG.  3   );   passing the hot stream ( 3 ,  FIG.  3   ) to pressure-reducing device- 1  (PRD- 1 ,  FIG.  3   ) and routing the partially vaporized crude oil to two phases separating vessel ( 4 ,  FIG.  3   ) having the plural trays and stripping media stream ( 5 S,  FIG.  3   );   heating the stream ( 5 ,  FIG.  4   ) from the vessel ( 4 ,  FIGS.  4   ) to 200° C. to 260° C. in heat exchanger network- 2 A (HEN- 2 A,  FIG.  4   );   feeding the heated stream ( 5 A,  FIG.  4   ) to a two-phase separating vessel ( 5 B,  FIG.  4   ) through pressure reducing device (PRD- 2 ,  FIG.  4   );   injecting vapor stream ( 5 C,  FIG.  4   ) from the vessel ( 5 B,  FIG.  4   ) to ADC column between HGO and Kerosene draw stages;   heating the liquid crude oil stream ( 5 D,  FIG.  4   ) obtained from the vessel ( 5 B,  FIG.  4   ) in the heat exchanger network- 3  (HEN 3 ,  FIG.  4   ) to a temperature from 270° C. to 330° C. and subsequently heated in a fired furnace (F 1 ,  FIG.  4   ) to a temperature from 350° C. to 400° C.;   routing of partially vaporized crude oil ( 6 ,  FIG.  4   ) to flash zone ( 9 ,  FIG.  4   ) of ADC ( 8 ,  FIG.  4   ) having the plurality of trays;   fractionating the vapor stream ( 7 H,  FIG.  4   ), vapor stream ( 5 C,  FIG.  4   ) and partially vaporized crude oil stream ( 6 ,  FIG.  4   ) in the ADC ( 8 ,  FIG.  4   ) to generate the different distillates, overhead vapor ( 15 ,  FIG.  4   ) and long residue stream ( 18 ,  FIG.  4   );   cooling the overhead vapor ( 15 ,  FIG.  3   ) using a condenser (E- 1 ,  FIG.  3   ) and fed to three-phase separating vessel (V 1 ,  FIG.  3   ) to separate vapor ( 16 ,  FIG.  3   ), liquid (reflux), which is routed to ADC ( 8 ) and sour water (SW- 1 ,  FIG.  3   );   routing the vapor stream ( 16 ) from V 1  to a two or three-phase separating vessel (V 2 ,  FIG.  3   ) after its cooling in a cooler (E- 2 ,  FIG.  3   ) at a temperature from 30° C. to 50° C. to separate unstabilized naphtha ( 17 ,  FIG.  3   ), sour water (SW- 2 ,  FIG.  3   ) and noncondensed gas (NCG) stream;   subjecting the unstabilized naphtha ( 17 ,  FIG.  3   ) to the distillation column ( 15 ,  FIG.  3   ) to produce the LPG, Light Naphtha (LN) and noncondensed vapor stream (NCV- 1 ,  FIG.  3   );   passing the heavy naphtha (HN) and kerosene, Light and Heavy Gas Oil (LGO and HGO) distillates from the different trays of ADC ( 8 ,  FIG.  3   ) to the reboiled side strippers ( 11 ,  FIG.  3   ), and steam stripers ( 12 ,  13  and  14 ,  FIG.  3   ), respectively to remove lighter hydrocarbon and to obtain heavy naphtha (HN) and kerosene, LGO and HGO distillate products;   processing the long residue stream ( 18 ,  FIG.  3   ) and steam stream (SS 4 ,  FIG.  3   ) in a vessel ( 14 A,  FIG.  3   ) having plural trays;   routing the vapor stream ( 18 A,  FIG.  3   ) from vessel ( 14 A,  FIG.  3   ) to the bottom of ADC ( 8 ,  FIG.  3   ) and liquid stream ( 18 B,  FIG.  3   ) from vessel ( 14 A,  FIG.  3   ) with furnace coil steam to a furnace (F 3 ,  FIG.  3   ); and   processing the partially vaporized crude ( 19 ,  FIG.  3   ) by known method in a Vacuum Distillation Column (VDC,  FIG.  1   ) to obtain the vacuum distillates and residue products.