CRUDE PETROLEUM OIL PROCESSING METHOD FOR CRUDE DISTILLATION UNIT

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims benefit of priority under 35 U.S.C. § 119 (a)-(d) to Indian patent application Ser. No. 20/241,1005918, filed Jan. 29, 2024, incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to improved crude petroleum oil processing methods for crude distillation unit (CDU) to fractionate the crude oil into the distillate products of desired purity. More particularly present disclosure relates to an improved crude petroleum oil processing method for CDU to achieve simultaneous reduction in energy consumption, creating the scope of processing more crude petroleum oil in atmospheric distillation column for its given diameter and/or reduction in vacuum system load of CDU.

BACKGROUND

The CDU comes to be at the beginning of the refinery to fractionate the crude petroleum oil into the products of the desired boiling range.

The Crude Petroleum Oil (CPO) is heated in Heat Exchanger Network (HEN) using the process hot streams prior to its feeding to desalter. Desalting of CPO is done with the help of water to dissolve soluble salt. The brine water containing salt is removed.

The desalted CPO is again preheated using the process hot streams in another HEN. The heated crude is processed either in Prefractionation Distillation Column (PDC) or in Flash Drum (FD) or directly routed to a fired furnace depending upon the CPO processing method selected in CDU design.

In the case of preheated crude processing in PDC, the Light Naphtha (LN) obtained from the top of PDC is directly routed to the naphtha stabilizing column. In the case of heated CPO routing to FD, the FD vapor is routed to the ADC or FD vapor is mixed with the FD liquid at some location in the heating tube or at the outlet of a fired furnace.

Any process scheme which can reduce energy consumption, GHG emission, operating cost and capital investment by overcoming the limitations in existing processes for crude oil processing in CDU is of great importance.

The present specification highlights an improved crude petroleum oil processing method for crude distillation unit (CDU) to fractionate the crude petroleum oil into the distillate products of desired purity without compromising distillate products yields and their quality.

SUMMARY

Accordingly, this disclosure provides a crude petroleum oil processing method for crude distillation unit (CDU) comprising the steps of:

• • (a) heating the crude petroleum oil (1, FIG. 3) in Heat Exchanger Network-1 (HEN1, FIG. 3) at a temperature in the range of 110-140° 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 (HEN2) at a temperature in the range of 180-260° C. or DCO is first preheated using the HEN2 at a temperature in the range of 180-260° C. and then mixed with water in one of the heat exchanger used in HEN2 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 (5S, FIG. 3);
  • (d) cooling the vapor stream (7) from the vessel (4) at a temperature in the range of 160-210° C. using Heat Exchanger Network-4 (HEN4, FIG. 3) and routing the cooled stream (7A, FIG. 3) to a two-phase separating vessel (7B, FIG. 3);
  • (e) superheating hydrocarbon vapor stream (7C, FIG. 3) from the vessel (7B, FIG. 3) in Heat Exchanger Network-5 (HEN5, FIG. 3) using the hot process streams and external heating sources;
  • (f) injecting the superheated hydrocarbon vapor stream (7H, 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 (7D, FIG. 3) from the vessel (7B, FIG. 3) to ADC at a single location or at different locations between HGO and Kerosene draw stages as 7D1, 7D2 and 7D3 streams;
  • (h) heating the liquid crude oil stream (5, FIG. 3) obtained from the vessel (4, FIG. 3) in the Heat Exchanger Network-3 (HEN3, FIG. 3) and fed to a fired furnace (F1, FIG. 3);
  • (i) routing of partially vaporized crude oil stream (6, FIG. 3) obtained from F1 to flash zone (9, FIG. 3) of atmospheric distillation column (8, FIG. 3) having the plurality of trays;
  • (j) fractionating the stream (7H, FIG. 3), stream (7D, 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 (V1, 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 (V2, FIG. 3) after its cooling in a cooler (E-2, FIG. 3) at a temperature in the range of 30-50° C. to separate unstabilized naphtha (17, FIG. 3), sour water (SW-2, FIG. 3) and non-condensed 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 (SS4, FIG. 3) in a vessel (14A, FIG. 3) having plural trays;
  • (p) routing the vapor stream (18A, FIG. 3) from vessel (14A, FIG. 3) to the bottom of ADC (8, FIG. 3) and liquid stream (18B, FIG. 3) from vessel (14A, FIG. 3) with furnace coil steam to a furnace (F3, FIG. 3);
  • (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.

In an embodiment, the DCO and water mixture generated in step (b) is heated in a Heat Exchanger Network (HEN 2) preferably at a temperature in the range of 180-260° C. and most preferably at a temperature in the range of 200-250° C.

In another embodiment, the striping media (5S) used in vessel (4) is steam or lighter hydrocarbons vapor stream having methane, ethane, propane, butane, pentane and light naphtha components.

In yet another embodiment, the vapor stream (7C) from step (e) is superheated preferably at a temperature in the range of 270-340° C. and most preferably at a temperature in the range of 290-325° C. in HEN5 using process streams and/or high-pressure steam.

In yet another embodiment, the liquid crude oil stream (5) obtained from the vessel (4) is heated in the Heat exchanger network-3 (HEN3) at a temperature in the range of 270-330° C. and subsequently heated in a fired furnace (F1) at a temperature in the range of 350-400° C.

In yet another embodiment, overhead vapor (15) from step (k) is cooled using a condenser (E-1) preferably at a temperature in the range of 70-130° C. and most preferably at a temperature in the range of 80-120° C.

In yet another embodiment, the liquid stream (18B) mixed with furnace coil steam is heated in a furnace (F3) preferably to the temperature range of 360-450° C. and most preferably to the temperature in the range of 380-430° C.

In yet another embodiment, 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 (10A, FIG. 5) of ADC (8) and steam (SS4, FIG. 5) is injected at the bottom tray of section (10A, FIG. 5) to generate the stream (18B, FIG. 5).

In yet another embodiment, a crude petroleum oil processing method for crude distillation unit further comprises the steps of:

• • (i) steps (a), (b), and (c) as described above;
  • (ii) heating the stream (5, FIG. 4) from the vessel (4, FIG. 4) preferably to the temperature in the range of 200-260° C. in heat exchanger network-2A (HEN-2A, FIG. 4);
  • (iii) feeding the heated stream (5A, FIG. 4) to a two-phase separating vessel (5B, FIG. 4) through pressure reducing device (PRD-2, FIG. 4);
  • (iv) injecting vapor stream (5C, FIG. 4) from the vessel (5B, FIG. 4) to ADC column between HGO and Kerosene draw stages;
  • (v) heating the liquid crude oil stream (5D, FIG. 4) obtained from the vessel (5B, FIG. 4) in the heat exchanger network-3 (HEN3, FIG. 4) to the temperature in the range of 270-330° C. and subsequently heated in a fired furnace (F1, FIG. 4) to the temperature in the range of 350-400° C.;
  • (vi) 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;
  • (vii) fractionating the vapor stream (7H, FIG. 4), vapor stream (5C, 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);
  • (viii) steps (k), (l), (m), (n), (o), (p), and (q) as described above.

A main object of this disclosure is to disclose improved crude petroleum oil processing methods for crude distillation unit (CDU) to achieve simultaneous reduction in energy consumption, creating the scope of processing more crude petroleum oil in atmospheric distillation column for its given diameter and/or reduction in vacuum system load of CDU.

Another object is to disclose improved processing schemes to reduce the severity of FD vapor's superheating to facilitate its superheating without using a fired furnace as required in the conventional processes.

Yet another object of the present disclosure is to disclose improved processing schemes over the crude oil processing scheme where superheated FD vapor is used as a stripping agent in ADC to reduce the load and size of VDC's ejector or vacuum pump.

Yet another object is to disclose an improved processing scheme for fractionating crude petroleum oil into products of the desired boiling range and quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a systematic representation of a conventional crude processing method for crude petroleum oil processing in CDU.

FIG. 2 is a systematic representation of a method disclosed in U.S. Pat. No. 9,546,324B2 for crude petroleum oil processing in CDU.

FIG. 3 is a systematic representation of a method disclosed in the present disclosure for crude petroleum oil processing in a CDU.

FIG. 4 is a systematic representation of another variation of a method disclosed in the present disclosure for crude petroleum oil processing in a CDU.

FIG. 5 is a systematic representation of another variation of a method disclosed in the present disclosure in FIG. 3 for crude petroleum oil processing in a CDU.

DETAILED DESCRIPTION

The present disclosure relates to improved crude petroleum oil processing methods for crude distillation unit (CDU) to overcome the disadvantages of existing crude petroleum oil processing methods. To describe the embodiments of the present disclosure, figures drawn in accordance with the existing crude oil processing methods and preferred embodiments of the present disclosure are prepared. The same numeral is used in drawings to refer to the same or similar stream or equipment elements. It is important to note that the embodiments herein are not limited to the precise arrangements of apparatus shown in drawings. The minor and common types of equipment whose application can be understood by the person of ordinary skill in the art, for example, pump to increase the pressure, valves to control the pressure and flows and levels, etc., have not been included in the drawings for keeping them simple. The reference to FIGS. 1-5 are made to describe the present embodiments in detail.

FIG. 1 represents the method conceptualized to construct a comparative example for establishing the basis for demonstrating the benefits of the embodiments herein over the most commonly used conventional crude petroleum oil processing in CDU in the refining industry. Crude petroleum oil (1) is heated in a HEN1 in the temperature range of 110-140° C. and fed to desalter (2), where it comes in contact with desalter water (DW) to remove the water-soluble salt. The brine water (BW) stream containing salt is routed to its downstream processing (not shown in FIG. 1). Desalted Crude Oil (DCO) obtained from desalter (2) is further heated in a HEN2 in the temperature range of 230-300° C. using hot process streams. The crude stream (3) was further heated in a fired furnace (F1) in the temperature range of 360-390° C. to generate partially vaporized crude oil stream (6). The partially vaporized crude oil stream (6) is fed to flash zone (9) of the atmospheric distillation column (ADC) (8), and stripping steam (6A) is fed at the bottom of ADC (8). The partially vaporized crude oil stream (6) is separated into atmospheric distillate products and long residue (18). The overhead vapor (15) is fed to a three-phase separating vessel (V1) after its cooling in the condenser (E-1) in the temperature range of 80-130° C. to separate the sour water stream (SW-1), the vapor stream (16) and reflux liquid. The liquid from VI is used as reflux to ADC (8). The vapor stream (16) from V1 is fed to a three-phase separating vessel (V2) after its cooling in a cooler (E-2) in the temperature range of 30-50° C. to generate the noncondensed gases (NCG), unstabilized naphtha stream (17) and sour water stream (SW-2). The stream (17) from V2 is routed to a distillation column (15) having plural trays to produce LPG, Light Naphtha (LN) product and noncondensed vapor-1 (NCV-1) stream.

The Heavy Naphtha (HN), kerosene, Light Gas Oil (LGO) and Heavy Gas Oil (HGO) distillates from the different trays of distillation column (8) are routed to their respective side strippers 11,12,13 and 14 to remove the dissolved lighter hydrocarbon for meeting the specifications of their final product. The heat of distillation column (8) having plural trays is removed by one or more pump-arounds (PA1, PA2 and PA3) and condenser (E-1).

The long residue (18) from the distillation column (8), along with furnace coil steam is heated in a fired furnace (F3) in the temperature range of 380-440° C. The partially vaporized long residue (19) is routed to the vacuum distillation column (VDC) for obtaining VC vapor, vacuum diesel (VD), Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO) and Vacuum Residue (VR) streams. VDC has plural trays and VDC bottom stripping steam at the bottom tray, equipped with pump-around (PA1, PA2, PA3) for heat removal. VC vapor is routed to a vacuum-generating device (VGD). The outlet streams from VGD are cooled in water coolers (WCs) and routed to a separating vessel (V3) to generate the noncondensed vapor-2 (NCV-2), hot well oil (HWO) and sour water (SW-3). Defined as suggested

FIG. 2 represents the method conceptualized to construct a comparative example for establishing the basis for demonstrating the benefits of the present embodiments over crude petroleum oil processing in CDU disclosed in U.S. Pat. No. 9,546,324 B2. Crude petroleum oil (1) is heated in a HEN1 in the temperature range of 110-140° C. and fed to desalter (2), where it comes in contact with desalter water (DW) to remove the water-soluble salt. The Brine Water (BW) stream containing salt is routed to its downstream processing (not shown in FIG. 2). Desalted Crude Oil (DCO) obtained from desalter is mixed with water (W), and the mixed stream is further heated in a HEN2 in the temperature range of 180-260° C. to generate a hot crude stream (3). The stream (3) is passed through the pressure-reducing device-1 (PRD-1) and fed to a two-phase separating vessel (4). The vapor stream (7) from the vessel (4) is further superheated in the temperature range of 300-370° C. using the combination of HEN4, and/or high-pressure steam heater (HPX), and furnace (F2) and/or separate vapor coils along with crude oil coils in the furnace (F1). The superheated vapor stream (7H) is injected into either the bottom tray of the stripping section (10) or a tray between the bottom tray and flash zone (9) of the atmospheric distillation column (ADC) (8). The liquid stream (5) is heated in a heat exchanger network-3 (HEN3) in the temperature range of 270-330° C. and subsequently heated in a fired furnace (F1) in the temperature range of 350-390° C. to generate the partially vaporized crude stream (6). The partially vaporized crude (6) is fed to flash zone (9) of the atmospheric distillation column (8) and stripping steam (6A) at the bottom of ADC (8). The stream (6) and stream (7H) are separated into atmospheric distillate products and long residue (18) in ADC (8). The downstream processing of distillate products (HN, kerosene, LGO and HGO), stream (15) and long residue stream (18) are the same as discussed in the description of FIG. 1.

Referring to FIG. 3, represents the method constructed in accordance with one of the embodiments described herein for crude petroleum oil (CPO) processing in CDU.

CPO (1) is heated in a HEN1 in the temperature range of 110-140° C. and fed to desalter (2), where it comes in contact with desalter water (DW) to remove the water-soluble salt. The Brine Water (BW) stream containing salt is routed to its downstream processing (not shown in FIG. 3). Desalted Crude Oil (DCO) obtained from desalter is either mixed with water (W) and the mixed stream is further heated in a HEN2 in the temperature range of 180-260° C. or DCO is first preheated using the HEN2 in the temperature range of 180-260° C. and then mixed with water in one of heat exchanger used in HEN 2. The hot stream (3) consisting of crude oil and water is passed through the pressure-reducing device-1 (PRD-1) and fed to a two-phase separating vessel (4). The separating vessels (4) can have a multiple trays and stripping media stream (5S) which can be steam or lighter hydrocarbons vapor stream having methane, ethane, propane, butane, pentane and light naphtha component sat vessel's (4) bottom section. The vapor stream (7) from the vessel (4) is cooled in the temperature range of 160-210° C. in HEN-4. The cooled stream (7A) is fed to the vessel (7B). The vapor stream (7C) from the vessel (7B) is further superheated in the temperature range of 290-340° C. in HEN5 using process streams and/or high-pressure steam. The superheated vapor stream (7H) is injected at either the bottom tray of the stripping section (10) or a tray between the bottom tray and flash zone (9) of the atmospheric distillation column (8). The liquid stream (5) from the vessel (4) is heated in the temperature range of 270-330° C. by using a heat exchanger network-3 (HEN3) and in the temperature range of 350-390° C. by the fired furnace (F1) to generate the partially vaporized crude stream (6). The partially vaporized crude (6) is fed to the flash zone (9) of ADC (8).

The liquid stream (7D) from the vessel (7B) is either routed at a single location or at different locations as 7D1, 7D2 and 7D3 by splitting the stream (7D) to ADC between flash zone (9) and kerosene distillate draw stage. The stream (6), vapor stream (7H) and liquid stream (7D) are fed and separated into atmospheric distillate products and long residue (18) in ADC (8). The downstream processing of distillate products (HN, Ferosene, LGO and HGO) and stream (15) are the same as discussed in the description of FIG. 1. The long residue stream (18) is fed to the top of the vessel (14A), having the plural trays. The stripping stream (SS-4) is injected into the bottom tray of the vessel (14A). The vapor stream (18A) from the vessel (14A) is routed to ADC (8) bottom, and liquid stream (18B) from the vessel (14A) and furnace coil steam are fed to a fired furnace (F3) to generate the partially vaporized crude stream (19). The downstream processing of stream (19) is the same as discussed in the description of FIG. 1.

Referring to FIG. 4, represents another variation of a method as described in FIG. 3, constructed in accordance with another one of the embodiments herein for crude CPO processing in CDU. The CPO processing scheme and operation are the same as described in FIG. 3 to generate the vapor stream (7) and liquid stream (5). The vapor stream (7) from the vessel (4) is further superheated in the temperature range of 290-340° C. in HEN5 using process streams and/or high-pressure steam. The superheated vapor stream (7H) is injected at either the bottom tray of the stripping section (10) of the atmospheric distillation column (8) or a tray between flash zone ann bottom tray of the stripping section (10). The liquid stream (5) is further heated in the temperature range of 200-240° C. in a heat exchanger network (HEN2A) using the process hot streams. The heated crude oil stream is passed through a pressure-reducing device-2 (PRD-2) and fed to a vessel (5B). The vapor stream (5C) from the vessel (5B) is routed to a tray at which the column's vapor final boiling point is higher than the vapor stream (5C) between HGO and Kerosene draw trays of ADC (8). The liquid stream (5D) is heated in the temperature range of 270-330° C. by using a heat exchanger network (HEN3) and in the temperature range of 350-390° C. by the fired furnace (F1) to generate the partially vaporized crude stream (6). The partially vaporized crude stream (6) is fed to the flash zone (9) of ADC (8). The stream (6), stream (7H) and stream (5C) are separated into atmospheric distillate products and long residue (18) in ADC (8). The downstream processing of distillate products (HN, Ferosene, LGO and HGO), and stream (15) are the same as discussed under the description of FIG. 1. The downstream processing of stream (18) till to form stream (19) is the same as discussed in the description of FIG. 3. The downstream processing of stream (19) is the same as discussed in the description of FIG. 1.

Referring to FIG. 5, represents another variation of a method as described in FIG. 3, constructed in accordance with one of the embodiments herein for crude petroleum oil processing in CDU. The CPO processing scheme and operation are the same as described in FIG. 3 till they generate stream 6, stream 7H and stream 7D and their routing to ADC (8) and their processing in ADC (8). The downstream processing of stream (15) is the same as discussed in the description of FIG. 3. The long residue stream (18) generated from ADC stripping section (10) is fed to a new separation section (10A) having plural trays added in ADC (8). The steam (SS4) is injected at the bottom tray of the new separation section (10A). The liquid stream (18B) from the new separation section (10A) and furnace coil steam are fed to a fired furnace (F3) to generate the partially vaporized crude stream (19). The downstream processing of stream (19) is the same as discussed in the description of FIG. 1.

It is well known that the CDU has the highest throughput among all units in the refinery. The conventional processing of crude petroleum oil in CDU consumes enormous amounts of energy and stripping steam. The quantitative requirement of energy and stripping steam for crude oil processing depends on the CDU design configuration, which, in turn, depends on the method used for crude petroleum oil processing in CDU. The person skilled in the art of crude distillation also understands that steam cost is much higher than fuel cost for the same thermal energy content in the refinery, since steam is produced by fuel with consequent energy efficiency losses in generation and use of steam.

The crude processing methods disclosed in U.S. Pat. No. 9,546,324 B2 suggest a significant reduction in energy, energy cost and increase in atmospheric gas oil yield under different scenarios. The disclosed crude oil processing method in conventional processes reduces the need for the ADC's bottom stripping steam by using superheated vapor generated in the process as stripping media. Thus, for a given ADC distillate rate, the methods disclosed herein also help reduce the maximum vapor flow rate or diameter of ADC for the similar lone residue or ADC distillates flow rates compared to the conventional method, as shown in FIG. 1. However, a close loop simulation of CDU as per the processing scheme shown in FIG. 2 constructed as in U.S. Pat. No. 9,546,324 B2 suggests a significant increase in vacuum system load and HWO generation for processing the same quantity of long residue to VDC compared to the conventional scheme used in the refinery as shown in FIG. 1. This may lead to higher capital cost requirements for the vacuum system, which includes VGD, pipelines and three-phase separation vessel for collecting HWO, sour water and non-condensable vapor (NCV-3) for grass root design of CDU and revamp of the vacuum system for enhanced load in existing CDU.

The higher vacuum system load will also lead to more utility requirements in vacuum system to generate the given vacuum in VDC. It can be envisaged that increased amount of ADC bottom stripping steam shall reduce the lighter material content along with long residue going to VDC column and thus can help to reduce the vacuum system load. However, the increased ADC bottom stripping steam to reduce the vacuum system load will also increase the energy cost and vapor flow rate in ADC. This implies that monetary advantages can be obtained by implementing the disclosed method due to savings on energy cost, ADC capital cost from lower ADC diameter requirement in grass root design and monetary benefits from increased ADC throughput in the existing design of CDU will be reduced significantly. Moreover, simulation results suggest that vacuum system load and HWO generation are still significantly higher compared to the conventional crude processing method, even after increasing the stripping steam by 50% compared to the base case.

There is always emphasis on developing new and improved methods for crude petroleum oil processing in CDU, which can improve the monetary and environmental advantages of CDU, considering it is the highest throughput unit in a refinery. Embodiments herein relate to an improved method for crude petroleum oil processing in the crude distillation unit for getting the distillate products of desired quality. More particularly, embodiments herein relate to improved methods for CPO processing for simultaneous reduction in thermal energy, reduction in vacuum system load, opportunity to increase the crude throughput for a given diameter of ADC and to eliminate the need for a fired furnace.

A crude petroleum oil processing method in ADC is developed by exploiting the best use of light fraction, medium fraction and heavy fraction of crude oil with the help of multiple two-phase separating vessels and new routing of these fractions to ADC to meet the previously stated objectives. The light fraction of crude oil is represented as its 85-90% is mixture of noncondensed vapor, LPG, LN and HN and its 10-15% is medium fraction. The medium fraction of crude oil is represented as its 85-90% of the is a mixture of kerosene, LGO and HGO) and its 10-15% is heavy fraction. The heavier fraction of crude oil is represented by a mixture of LGO, HGO and Long residue.

Moreover, a new processing scheme for long residue obtained from the existing design of ADC's stripping section is synthesized to reduce the vapor load to the vacuum system (VS), which is used to generate the vacuum in VDC and to eliminate the need of a fired furnace for superheating the FD vapor prior to its routing to ADC bottom. It may be noted the FD vapor is superheated to a high-temperature level to reduce the naphtha range hydrocarbon carryover with long residue and thus VDC vacuum system load using a process heat exchanger and a fired furnace before it enters ADC bottom. The proposed method developed for long residue processing in embodiments enables the process flexibility to reduce the superheating temperature level requirement to a value which does not need the fired furnace application without increasing the VDC vacuum system load. The fouling of heat exchangers and furnace operation over time shall also lead to the variation in the superheating temperature of hydrocarbon vapor. The proposed method in the embodiments herein also enables the process flexibility to handle the variation in the superheating temperature level of hydrocarbon and water vapor mix stream without affecting the VDC vacuum generation system load and, thus, smooth operation of VDC.

Embodiments herein provide methods for processing the crude petroleum oil and long reside (LR) to reduce the diameter requirement of ADC for a given crude flow rate or increase the crude processing capacity for a given diameter, reduce VDC vacuum generation system load to reduce the energy cost or revamp requirement for the existing system, to eliminate the need of a fired furnace to superheat the FD's vapor without increasing the vacuum system load and to achieve significant reduction in energy consumption.

EXAMPLES

The following examples are given as a way of illustration only and should not be construed to limit the scope of the claims appended to this disclosure.

The following four examples constructed using the well-known commercial simulation software (ASPEN HYSYS) to design the crude distillation unit. The properties of Iranian heavy crude used in these examples are given in Table 1.

TABLE 1
Iranian heavy crude properties

	Initial	Final	Cut Yield	Std Liquid
	temperature	temperature	By Vol	Density
Crude	(° C.)	(° C.)	(%)	(kg/m3)

Whole Crude	IBP	FBP	100.0	911.9
Cut1	IBP	40	4.1	568.8
Cut2	40.0	90.6	6.1	693.9
Cut3	90.6	141.2	9.5	738.0
Cut4	141.2	191.8	9.3	773.6
Cut5	191.8	242.4	7.8	813.2
Cut6	242.4	292.9	8.0	853.3
Cut7	292.9	343.5	8.2	891.8
Cut8	343.5	394.1	8.0	930.8
Cut9	394.1	444.7	7.5	969.7
Cut10	444.7	495.3	6.8	1011.7
Cut11	495.3	545.9	5.9	1051.5
Cut12	545.9	596.5	5.0	1090.2
Cut13	596.5	647.1	4.0	1131.3
Cut14	647.1	697.6	3.1	1170.2
Cut15	697.6	748.2	2.3	1209.2
Cut16	748.2	798.8	1.6	1248.3
Cut17	798.8	849.4	1.1	1287.3
Cut18	849.4	900.0	0.7	1326.4
Cut19	900.0	950.0	1.1	1359.1
Cut20	950.0	FBP	0.0	1395.5

Example 1 represents the base case-1 (BC-1). This example is exemplary and constructed as per the conventional crude oil processing method used for CPO distillation in CDU for establishing the basis to compare the quantitative advantages of the methods herein.

Example 2 represents the base case-2 (BC-2). This example is also exemplary and constructed as per the method used for CPO distillation in CDU, disclosed in U.S. Pat. No. 9,546,324 B2 for establishing the basis to compare the quantitative advantages of the methods herein.

Example 3 represents the present Case-1 (PC-1). This example illustrates the method-1 for crude petroleum oil processing in CDU to reduce the thermal energy, reduce the vacuum system load, reduce the ADC diameter for fixed crude flow rate and reduce the superheating temperature level of a light fraction of crude oil and water mixture vapor's to eliminate the need of fired furnace.

Example 4 represents the present Case-2 (PC-2). This example illustrates the method-2 for crude petroleum oil processing in CDU to reduce the thermal energy, reduce the vacuum system load, reduce the ADC diameter for fixed crude flow rate and reduce the superheating temperature level of a light fraction of crude oil and water mixture vapor's to eliminate the need of fired furnace.

The values of operating parameters such as crude flow rate, the temperature of the partially vaporized crude stream (6), ADC-furnace (F1) outlet pressure and temperature, ADC top pressure, pressure drop across the ADC and condensers (E-1 and E-2), number of trays in ADC, ADC's trays efficiency, partially vaporized crude oil stream (6) entry location to ADC, pump-arounds draw and return stages, product's distillates draw stages, draw and return stages for strippers, number of trays and their efficacy in strippers, VDC-furnace (F3) outlet pressure and temperature, VDC top pressure, pressure drop across the VDC, number of trays in VDC, VDC's trays efficiency, partially vaporized crude oil stream (19) crude entry location to VDC, pump-arounds draw and return stages in VDC, product's distillates draw stages in VDC are same in all the examples constructed herein to facilitates a realistic quantification of benefits.

Pinch analysis is a proven tool for estimating the minimum thermal energy of the process without designing the heat exchanger networks. Therefore, pinch analysis with a delta min temperature of 20° C. is used to estimate the minimum thermal energy requirement of the processes used in all examples herein to eliminate the effect of change in the heat exchanger network design in all examples.

Moreover, the vapor from the VDC top, which is routed to the vacuum-generating device, is divided into three components: steam, condensable hydrocarbon, and cracked gas/air leakage (noncondensable). The flow rate and molecular weight of each component are estimated. The ejector manufacturer uses this information on the VDC top's vapor to convert the VDC top vapor flow rate to air or water vapor equivalent using Heat Exchange Institute (HEI) methods or, in some cases, DIN standards. The process loads are converted to equivalents to allow for direct comparison to ejector test curves since the testing process does not use hydrocarbon vapors (Scott Golden et al. De-mystifying vacuum ejector systems. PTQ Q1 2023, pp-29-37). Conventional methods have converted these components flow rate into water vapor equivalent flow rate to understand the effect of CDU operation and VDC operating conditions on ejector load (Scott Golden et al., Focused revamp increases diesel and HVGO recovery PTQ Q3 2023, pp-19-30). Moreover, the information provided in previous methods suggests that around 2.5-3.5 TPH of MP steam requirement is needed to remove the vapor corresponding to 1 TPH water vapor equivalent from VDC to generate the vacuum of 19 mmHgabs in VDC. This implies that an increase in vacuum system load will significantly increase the MP steam requirement in the ejector.

Example 1

The flow scheme shown in FIG. 1 is used for this example. The 1163.2 tons/hr crude containing 3.2 tons of water is heated to a temperature of 385° C. using a heat exchanger network and a fired furnace (F1). The partially vaporized liquid stream (6) is routed to the flash zone (9) of the ADC containing 58 trays. The 13.0 tons/hr stripping steam (6A) is fed at ADC's bottom. The vapor stream (15) is processed is cooled using E-1 to the temperature of 103° C. and fed to at three-phase separating vessel (V-1) to generate a vapor stream (16), reflux and sour water stream (SW-1). The vapor stream (16) is further cooled using E-2 to the temperature of 40° C. and fed to a three-phase separating vessel (V-2) to generate an unstabilized Light Naphtha stream (17) and sour water stream (SW-2) and Noncondensed gases (NCG) stream. The ADC was operated at a top tray pressure of 3.7 kg/cm²a with E-1's pressure drop of 0.5 kg/cm², E-2's pressure drop of 0.25 kg/cm² and column's pressure drop of 0.5 kg/cm².

The vapor from the flash zone is fractionated into distillates vis-à-vis unstabilized Light Naphtha (LN), Heavy Naphtha (HN), kerosene, Light Gas Oil (LGO), and Heavy Gas Oil (HGO). Liquid falling from the flash zone is stripped out using the stripping steam (6A) at the bottom tray of ADC (8). The HN distillate is routed to a reboiled-side stripper (11), and Kerosene, LGO and HGO distillates are routed to their respective steam-stripped side strippers 12,13 and 14 to remove the dissolved lighter components to meet the products ASTM D-86 distillation five volume percent point temperature. The kerosene-PA, LGO-PA and HGO-PA pump arounds were used to remove the heat at different temperature levels from the column. The unstabilized light naphtha stream (17) is processed in a distillation column (15) having 20 trays and 10 kg/cm² operating pressure to obtain the LPG, Light Naphtha (LN) and noncondensed vapor (NCV-1).

The long residue (18), along with 5.0 tons/hr furnace coil steam, is heated in a fired furnace (F3) to the temperature value of 425° C. The partially vaporized crude (19) is processed in a Vacuum Distillation Column (VDC). VDC has 16 theoretical trays, top pressure of 2.66 KPa, and a bottom pressure of 6.00 KPa. VDC produces distillate products vis-à-vis Vacuum Diesel (VD), Light Vacuum Gas Oil (LVGO), Heavy Vacuum Gas Oil (HVGO), vacuum residue (VR) and VC vapor. The VD, LVGO, and HVGO products were withdrawn from the 15^th, 9^th and 6^th trays of VDC, having tray numbering from bottom to top. The 7.0 tons/hr stripping steam is used at the bottom of VDC. The VC vapor from VDC top is routed to a vacuum system (VS) consisting of a vacuum generation device (VGD), water coolers (WCs) and three phase separating vessel (V-3) to collect the noncondensed vapor-2 (NCV-2), hot well oil (HWO) and sour water-3 (SW-3). The Top, LVGO and HVGO pump arounds (TOPPA, LVGOPA, HVGOPA) were used to remove the heat at different temperature levels from the VDC. The details of pump-arounds and side strippers for ADC and pump-arounds for VDC are given in Table 2.

TABLE 2
Details of pump-arounds and side strippers used

		Draw	Return	Flow	Temperature
	Pump Around	tray	tray	[tons/h]	drop, ° C.

ADC's Pump Around (PA.)

	Kerosene- PA	38	40	620.0	50.00
	LGO-PA	24	26	570.0	70.00
	HGO-PA	15	17	385.0	60.00

VDC's Pump-around (PA)

	TOPPA	14	15	220.0	92.5
	LVGOPA	8	9	461.0	65.2
	HVGOPA	5	6	817.0	53.0

ADC's Strippers

	No of	Liquid	Vapor	Stripping steam,
	trays/	Draw	Return	Tons/hr/reboiler
Strippers	Efficiency	tray	tray	duty (Mkcal/hr)
HN reboiled	6/0.5	48	50	0.294
Stripper
Kerosene steam	6/0.3	38	40	5.41
Stripper
LGO steam Stripper	6/0.3	24	26	2.42
HGO steam Stripper	6/0.3	15	17	1.20

The flow rate of different products produced from ADC and VDC for Example 1, are given in Table 3.

TABLE 3
The flow rate (Tons per hr) of products
produced from ADC and VDC

	Products	Product Flow rate, TPH

	Non-Condensables	2.32
	LPG	16.00
	Light Naphtha (LN)	110.70
	Heavy Naphtha (HN)	13.73
	Kerosene	194.90
	Light Gas Oil (LGO)	109.80
	Heavy Gas Oil (HGO)	66.81
	Hot well oil (HWO)	3.06
	Vacuum Diesel (VD.)	51.73
	Light Vacuum Gas Oil (LVGO)	143.72
	Heavy Vacuum Gas Oil (HVGO)	163.60
	Slop Product (Slop)	15.00
	VR	269.53

Further, measurement of ASTM D-86 temperatures corresponding to their 5 and 95 volume percent specification of distillate products is a known method of evaluating the quality of distillate products from the crude distillation unit. The performance of a crude distillation is evaluated using the ASTM 5-95 gaps separation criteria. The details of 5 and 95 volume percent temperature and 5-95 gaps for adjacent product streams are given in Table 4.

TABLE 4
ASTM D-86/D-11605 and 95 volume percent temperature
5-95 gaps for adjacent product streams

	Temp.		Temp.		Temp.
Stream	° C.	Stream	° C.	Stream	° C.

95 volume %	5 volume %	ASTM 5-95 Gap

LN_95	115.4	HN-5	120.7	HN − LN	5.3
HN_95	160.0	Kero_5	149.9	Kero − HN	−10.1
Kero_95	240.0	LGO_5	226.6	LGO − Kero	−13.4
LGO_95	320.0	HGO_5	287.3	HGO − LGO	−32.7
VD_95	360.0	LVGO_5	369.3	LVGO − VD	9.3
LVGO_95	480.0	HVGO_5	431.2	HVGO − LVGO	−48.8
HVGO_95	580.0	VR_5	545.9	VR − HVGO	−34.1

The enthalpy data, supply temperature and target temperatures for hot and cold streams for carrying out the pinch analysis were collected from a converged simulation model of the process flow scheme used for Example 1 (FIG. 11). In Example 1, the water vapor equivalent flow rate for VDC vapor is estimated using the ratios predicted using the information given in Scott Golden et al., Focused revamp increases diesel and HVGO recovery PTQ Q3 2023, pp-19-30 for different components in VDC vapor.

The details of primary hot thermal utilities requirement and cost, the vacuum system load in terms of water vapor equivalent, and the predicted diameter of ADC are given in Table 5. The cold utility has been neglected due to its minor contribution to operating energy costs.

TABLE 5
Detail of thermal utilities requirement, the vacuum system load in
terms of water vapor equivalent, and predicted diameter of ADC.

	Utility	Quantity

	Stripping and F3-coil steam, Tons/hr	34.03
	Min Hot utility (F1) duty, Mkcal/h	63.38
	VDC Furnace (F3) Duty, Mkcal/h	32.18
	ADC Diameter, Meter	6.956
	Vacuum system load in term of water vapor	14.96
	equivalent, Tons/hr

Example 2

The values of operating parameters such as crude flow rate, the temperature of the partially vaporized crude stream (6), ADC-furnace (F1) outlet pressure and temperature, ADC top pressure, pressure drop across the ADC and condensers, number of trays in ADC, ADC's trays efficiency, partially vaporized crude oil stream (6) entry location to ADC, pump-arounds draw and return stages, product's distillates draw stages, draw and return stages for strippers, number of trays and their efficacy in strippers, VDC-furnace (F3) outlet pressure and temperature, VDC top pressure, pressure drop across the VDC, number of trays in VDC, VDC's trays efficiency, partially vaporized crude oil stream (19) crude entry location to VDC, pump-arounds draw and return stages in VDC, product's distillates draw stages in VDC used in this example are same as used in Example 1.

It is known that the condensable oil rate is a function of vacuum tower top pressure and temperature, amount of steam used, and atmospheric crude column bottoms stripping performance or lighter hydrocarbon carryover with long residue (LR). A higher stripping steam flow rate reduces the amount of lighter hydrocarbon carryover with long residue and may reduce the vacuum system load. Therefore, two cases were considered in the Example 2. Case-I represents when the ADC bottom stripping rate compared to Example 1 is reduced to the value when the LR flow rate is similar to as obtained in Example 1 from the conventional method. Case II represents a scenario when the ADC bottom stripping rate is 1.5 times the stripping team used in Case I of Example 2 to understand the effect of increased striping steam on vacuum system load.

The flow scheme for this example is shown in FIG. 2. The 1163.2 tons/hr Crude petroleum oil (1) containing 3.2 tons of water is heated in a HEN1 in the temperature range of 125° C. The heated stream (DCO) is mixed with 3.0 TPH water (W). The crude oil and water mixed stream is further heated in a HEN2 to the temperature range of 220° C. to generate the hot crude stream (3). The stream (3) is passed through the pressure-reducing device-1 (PRD-1) and fed to the vessel (4) at 6 kg/cm² pressure. The vapor stream (7) from the vessel (4) is further superheated to the temperature of 360° C. using the combination of HEN4, and/or high-pressure steam heater (HPX), and/or furnace (F2) and/or separate vapor coils along with crude oil coils in the furnace (F1).

The superheated vapor stream (7H) is injected at the bottom tray of the stripping section (10) of the atmospheric distillation column (8). The liquid stream (5) is heated 385° C. using a heat exchanger network (HEN3) and fired furnace (F1) to generate the partially vaporized crude stream (6). The partially vaporized crude (6) is fed to the flash zone (9) of the atmospheric distillation column (8). The stripping steam (6A) at the flow rate of 5.0 TPH in Case-I and 7.5 TPH in Case-II is fed at the bottom of ADC (8).

The crude oil stream (6) and vapor stream (6H) are separated into atmospheric distillate products and long residue (18) in ADC (8). The downstream processing of distillate products (HN, Kerosene, LGo and HGO), ADC top vapor stream (15) and long residue stream (18) are the same as discussed in the description of FIG. 1. The ADC and VDC pump around flow rate and strippers stripping steam were adjusted to meet the product's ASTM D-86/D-1160 5% temperatures. VDC top temperature is maintained at a temperature value of 75° C., similar to the Example 1 and delta T around the VDC TOPPA was allowed to change accordingly. The flow rates of different products produced from ADC and VDC are given in Table 6.

TABLE 6
Flow rate of products produced from ADC and VDC

Product Flow rate, TPH

	Products	Case-I	Case-II

	Non-Condensables	4.02	3.93
	LPG	16.00	16.01
	Light Naphtha (LN)	110.13	110.18
	Heavy Naphtha (HN)	4.87	6.56
	Kerosene	195.50	195.12
	Light Gas Oil (LGO)	115.84	116.59
	Heavy Gas Oil (HGO)	69.66	72.07
	Hot well oil (HWO)	8.83	8.00
	Vacuum Diesel (VD)	43.62	39.53
	Light Vacuum Gas Oil (LVGO)	144.29	144.43
	Heavy Vacuum Gas Oil (HVGO)	163.36	163.39
	Slop Product (Slop)	15.00	15.00
	VR	269.84	270.15

The details of 5 and 95 volume percent temperature for product streams and 5-95 gaps for adjacent product streams are given in Table 7.

TABLE 7
ASTM D-86/D-1160 5 and 95 volume percent temperature 5-95 gaps for adjacent
product streams in degrees Celsius.

95 volume % (° C.)

5 volume % (° C.)

ASTM 5-95 Gap (° C.)

	Case-	Case-		Case-	Case-		Case-	Case-
Product	I	II	Product	I	II	Products	I	II

LN_95	115.7	115.2	HN-5	120.9	120.9	HN-LN	5.1	120.9
HN_95	160.0	160.0	Kero_5	149.1	149.7	Kero-HN	−10.9	−10.3
Kero_95	240.0	240.0	LGO_5	225.5	226.5	LGO-Kero	−14.5	−13.5
LGO_95	320.0	320.0	HGO_5	285.8	286.1	HGO-LGO	−34.2	−33.9
VD_95	360.0	360.0	LVGO_5	369.6	369.1	LVGO-VD	9.6	9.1
LVGO_95	480.0	480.0	HVGO_5	431.1	430.6	HVGO-	−48.9	−49.4
						LVGO
HVGO_95	580.0	580.0	VR_5	545.7	545.3	VR-HVGO	−34.3	−34.7

The hot utilities requirement, vacuum system load and ADC diameters were estimated using the same methods as used in Example 1. The details of primary thermal utilities requirement, Vacuum system load in terms of water vapor equivalent, and predicted diameter of ADC are given in Table 8. The cold utility has been neglected due to its minor contribution to operating energy costs.

TABLE 8
Detail of thermal utilities requirement, the vacuum system load
in terms of water vapor equivalent, and predicted diameter of ADC

Quantity

Utility	Case-I	Case-II

Stripping and coil steam, Tons/hr	24.93	27.43
Min Hot utility (F1) duty, Mkcal/h	56.16	56.10
VDC Furnace (F3) Duty, Mkcal/h	34.71	34.69
ADC Diameter, Meter	6.890	6.957
Vacuum system load in terms of water vapor	17.50	17.1
equivalent, Tons/hr

Example 3

The flow scheme for this example is shown in FIG. 3. The 1163.2 tons/hr Crude petroleum oil (1) containing 3.2 tons of water is heated in a HEN1 in the temperature range of 125° C. The desalted Crude Oil (DCO) obtained from desalter is mixed with 3.0 TPH water (W), and mixed stream is further heated in a HEN2 to the temperature range of 235° C. in case-I and 245° C. in case-II to generate the hot crude stream (3). The stream (3) is passed through the pressure-reducing device-1 (PRD-1) and fed to the two-phase separating vessel (4) to generate the vapor stream (7) and liquid stream (5). The vapor stream (7) from the vessel (4) is cooled to a temperature of 178.3° C. The cooled stream (7A) is fed to the other two-phase separating vessel (7B). The vapor stream (7C) from the vessel (7B) is further superheated to the temperature range of 320° C. against 360° C. in Example 2 in HEN5 using process streams. The superheated vapor stream (7H) is injected into the bottom tray of the stripping section (10) of the atmospheric distillation column (8). The liquid stream (7D) from the vessel (7B) is routed to the 26th tray from the bottom in ADC. The liquid stream (5) from the vessel (4) is heated to 385° C. using a heat exchanger network (HEN3) and fired furnace (F1) to generate the partially vaporized crude stream (6). The partially vaporized crude (6) is fed to the flash zone (9) of ADC (8). The stream (6), vapor stream (7H), and liquid stream (7D) are fed in ADC (8) and separated into atmospheric distillate products and long residue (18). The downstream processing of distillate products (HN, Ferosene, LGO and HGO), and stream (15) are the same as discussed in the description of FIG. 1.

The long residue stream (18) is fed to the top section of the vessel (14A), having 6 trays with an efficiency of 0.30. The 6.0 TPH stream (SS-4) is injected into the bottom tray of the vessel (14A). The vapor stream (18A) from the vessel (14A) is routed to ADC (8) bottom, and liquid stream (18B) and furnace oil steam are fed to a fired furnace (F3) to generate the partially vaporized crude stream (19). The downstream processing of stream (19) in VDC is the same as discussed in the description of FIG. 1.

The ADC and VDC pump arounds flow rate and strippers stripping steam were adjusted to meet ADTM D-86/D-1160 5% temperatures of the products. VDC top temperature is maintained at a temperature value of 75° C. similar to examples 1 and 2, and delta T around the VDC TOPPA was allowed to change accordingly.

The flow rates of different products produced from ADC and VDC are given in Table 9.

TABLE 9
Flow rate of products produced from ADC and VDC

Product Flow rate, TPH

	Products	Case-I	Case-II

	Non-Condensables	2.55	2.55
	LPG	16.00	16.00
	Light Naphtha (LN)	110.58	110.55
	Heavy Naphtha (HN)	11.53	11.64
	Kerosene	194.52	193.86
	Light Gas Oil (LGO)	118.50	118.96
	Heavy Gas Oil (HGO)	72.41	72.44
	Hot well oil (HWO)	3.31	3.49
	Vacuum Diesel (VD.)	37.33	37.17
	Light Vacuum Gas Oil (LVGO)	145.41	145.46
	Heavy Vacuum Gas Oil (HVGO)	163.53	163.52
	Slop Product (Slop)	15.00	15.00
	VR	270.06	270.04

The details of 5 and 95 volume percent temperature for product streams and 5-95 gaps for adjacent product streams are given in Table 10.

TABLE 10
ASTM D-86/D-1160 5 and 95 volume percent temperature 5-95 gaps for adjacent
product streams in degrees Celsius.

95 volume % ,° C.

5 volume %,° C.

ASTM 5-95 Gap, ° C.

	Case-	Case-		Case-	Case-		Case-	Case-
Product	I	II	Product	I	II	Products	I	II

LN_95	115.7	115.4	HN-5	120.2	120.2	HN-LN	4.5	4.9
HN_95	159.9	160.1	Kero_5	149.2	149.2	Kero-HN	−10.7	−10.8
Kero_95	240.0	240.0	LGO_5	224.6	224.3	LGO-Kero	−15.4	−15.7
LGO_95	320.0	320.0	HGO_5	285.6	285.5	HGO-LGO	−34.4	−34.5
VD_95	360.0	360.0	LVGO_5	368.1	368.1	LVGO-VD	8.1	8.1
LVGO_95	480.0	480.0	HVGO_5	430.4	430.4	HVGO-LVGO	−49.6	−49.6
HVGO_95	580.0	580.0	VR_5	545.4	545.4	VR-HVGO	−34.6	−34.6

The hot utilities requirement, vacuum system load and ADC diameters were estimated using the same methodology as used in Example 1. The details of primary thermal utilities requirements, the vacuum system load in terms of water vapor equivalent, and the predicted diameter of ADC are given in Table 11. The cold utility has been neglected due to its minor contribution to operating energy costs.

TABLE 11
Detail of primary thermal utilities requirement,
the Vacuum system load in terms of water vapor
equivalent, and predicted diameter of ADC.

Quantity

Utility	Case-I	Case-II

Stripping and coil steam, Tons/hr	27.03	27.03
Min Hot utility (F1) duty, Mkcal/h	51.97	50.34
VDC Furnace (F3) Duty, Mkcal/h	37.93	38.44
ADC Diameter, Meter	6.856	6.775
Vacuum system load in terms of water vapor	15.4	15.5
equivalent, Tons/hr

Example 4

The flow scheme for this example is shown in FIG. 4. The 1163.2 tons/hr Crude petroleum oil (1) containing 3.2 tons of water is heated in a HEN1 in the temperature range of 125° C. The desalted crude oil (DCO) is mixed with 3.5 TPH water (W), and the mixed stream is further heated in a HEN2 to the temperature of 220° C. to generate the hot crude stream (3). The stream (3) is passed through the pressure-reducing device-1 (PRD-1) and fed to the two-phase separating vessel (4) operating at a pressure of 6.0 kg/cm² to generate the vapor stream (7) and liquid stream (5). The vapor stream (7) from the vessel (4) is further superheated to the temperature of 320° C. in HEN5 using process streams. The superheated vapor stream (7H) is injected into the bottom tray of the atmospheric distillation column (8).

The liquid stream (5) from vessel (4) is heated using the HEN-2A to the temperature of 225° C. in case-I and 235° C. in case-II is routed through pressure-reducing device-2 (PRD-2) to two phases separating vessel (5B) operating at 5.8 kg/cm² pressure. The vapor stream (5C) from the vessel (5B) is routed to the ADC column (8) at tray 27th from the bottom. The liquid stream (5D) from the vessel (5B) is heated to the temperature of 385° C. using a heat exchanger network (HEN3) and fired furnace (F1) to generate the partially vaporized crude stream (6). The partially vaporized crude (6) is fed to the flash zone (9) of ADC (8). The stream (6), vapor stream (5C) and vapor stream (7H) are separated into atmospheric distillate products and long residue (18) in ADC (8). The downstream processing of distillate products (HN, Ferosene, LGO and HGO), and ADC top stream (15) are the same as discussed in the description of FIG. 1.

The downstream processing of the long residue stream (18) is the same as discussed in Example 3, corresponding to FIG. 3. The downstream processing of stream (19) is the same as discussed in Example 1 under the description of FIG. 1. The ADC and VDC pump arounds flow rate and strippers stripping steam were finetuned to meet ADTM D-86/D-1160 5% temperatures of the products. VDC top temperature is maintained at a temperature value of 75° C. similar to Example 1, and delta T around the VDC TOPPA was allowed to change accordingly. The flow rates of different products produced from ADC and VDC are given in Table 12.0.

TABLE 12
Flow rate of products produced from ADC and VDC

Product Flow rate, TPH

	Products	Case-I	Case-II

	Non-Condensables	2.53	2.53
	LPG	16.00	16.00
	Light Naphtha (LN)	110.36	109.03
	Heavy Naphtha (HN)	15.38	15.82
	Kerosene	192.69	192.77
	Light Gas Oil (LGO)	116.43	115.46
	Heavy Gas Oil (HGO)	70.18	69.23
	Hot well oil (HWO)	2.65	2.69
	Vacuum Diesel (VD.)	41.64	42.94
	Light Vacuum Gas Oil (LVGO)	145.38	145.45
	Heavy Vacuum Gas Oil (HVGO)	163.48	163.44
	Slop Product (Slop)	15.00	15.00
	VR	269.91	269.84

The details of 5 and 95 volume percent temperature for product streams and 5-95 gaps for adjacent product streams are given in Table 13.

TABLE 13
ASTM D-86/D-1160 5 and 95 volume percent temperature 5-95 gaps for adjacent
products streams in degrees Celsius

95 volume % (° C.)

5 volume % (° C.)

ASTM 5-95 Gap (° C.)

	Case	Case		Case-	Case-		Case	Case
Product	I	II	Product	I	II	Products	I	II

LN_95	116.9	115.0	HN-5	119.5	119.6	HN-LN	2.7	4.6
HN_95	160.0	160.0	Kero_5	150.0	150.3	Kero-HN	−10.0	−9.7
Kero_95	240.0	240.0	LGO_5	225.1	226.3	LGO-Kero	−14.9	−13.7
LGO_95	320.0	320.0	HGO_5	285.0	285.1	HGO-LGO	−35.0	−34.9
VD_95	360.0	360.0	LVGO_5	368.3	368.4	LVGO-VD	8.3	8.4
LVGO_95	480.0	480.0	HVGO_5	430.6	430.7	HVGO-LVGO	−49.4	−49.3
HVGO_95	580.0	580.0	VR 5	545.5	545.6	VR-HVGO	−34.5	−34.4

The utilities requirement, vacuum system load and ADC diameters were estimated using the same methodology as used in Example 1. The details of major thermal utilities requirement, Vacuum system load in term of water vapor equivalent, and predicted diameter of ADC are given in Table 14. The cold utility has been neglected due to its minor contribution in operating energy cost.

TABLE 14
Detail of major thermal utilities requirement, Vacuum system load
in term of water vapor equivalent, and predicted diameter of ADC

Quantity

Utility	Case-I	Case-II

Stripping and coil steam, Tons/hr	26.62	26.62
Min Hot utility (F1) duty, Mkcal/h	54.87	53.66
VDC Furnace (F3) Duty, Mkcal/h	35.97	36.18
ADC Diameter, Meter	6.838	6.781
Vacuum system load in term of water vapor	15.1	15.1
equivalent, Tons/hr

Comparative results of Example 1, Example 2, Example 3, and Example 4 constructed with reference to crude oil processing methods shown in FIGS. 1, 2, 3, and 4 to process the 1160 TPH dry crude indicate that the quality and separation criteria of distillates products were maintained for distillates products. The comparative results for key parameters estimated in Examples 1 and 2 constructed as literature disclosures, and examples 3 and 4 constructed as per embodiments herein are given in Table 15. The average values of case-I and case-II, for Examples 2, 3, and 4 for critical parameters are given in Table 15 as comparative results.

TABLE 15
Comparative results

	Exam-	Exam-	Exam-	Exam-
Key parameter	ple 1	ple 2	ple 3	ple 4

Stripping and coil steam, Tons/hr	34.03	26.18	27.03	26.62
Min Hot utility (F1) duty,	63.38	56.13	51.16	54.27
Mkcal/h
VDC Furnace (F3) Duty, Mkcal/h	32.18	34.70	38.19	36.08
ADC Diameter, Meter	6.96	6.92	6.82	6.81
Vacuum system load in terms of	14.96	17.30	15.45	15.10
water vapor equivalent, Tons/hr
Energy requirement, Mkcal/h	112.58	103.92	102.86	103.65

It is known to the person skilled in the art that the crude processing method, which needs a lower diameter of ADC for a given crude flow rate, will provide the opportunity to process either more flow rate of crude oil in the existing CDU or reduce the cost in grass root design. Therefore, the percent increase in throughput for proposed crude oil processing methods was also estimated using the estimated diameter, flooding velocity of 2.0 m/sec and active area of 70%.

Comparative results in Table 15 indicate that there is a reduction in steam and thermal energy (ADC and VDC furnaces fuel) consumption by 20.57%, 6.51% respectively an increase in ADC throughput by 3.98% and an increase in vacuum system load are by 3.28% for Example 3 constructed corresponding to embodiments herein, compared to Example 1 constructed corresponding conventional processing methods. Moreover, there is a decrease in vacuum system load by 10.7% and an increase in ADC throughput by 3.09% for Example 3 constructed corresponding to embodiments herein, compared to Example 2 constructed corresponding conventional processing methods.

There is a reduction in steam consumption by 21.77%, a reduction in thermal energy (\ADC and VDC furnaces fuel) by 5.46%, an increase in vacuum system load by 0.94%, and increase in ADC throughput are, 4.17%, for Example 4 compared to Example 1. There is a decrease in vacuum system load by 12.72% and an opportunity to increase in ADC throughput by 3.29% in Example 4 with respect to Example 2.

The vapor stream obtained from two phases separating vessel (7B) is superheated to 320° C. in examples 3 and 4 constructed, corresponding to embodiments herein, compared to 360° C. in Example 2 constructed as per conventional methods. It is known to the person skilled in the art that the temperature level of 320° C. can be attained by using the hot process stream generated in CDU, whereas to achieve the temperature of 360° C. there is a need for a fired furnace. Overall, there is an opportunity for a noticeable reduction in thermal energy and steam consumption, creating an opportunity to increase the ADC throughput in existing CDU, reducing the ADC's diameter in grassroots design and eliminating the need of a fired furnace to superheat the light fraction of crude oil vapor before its routing to ADC by implementing the crude processing methods disclosed herein. There is a significant reduction is vacuum system load, leading to a huge savings potential of MP steam for the crude processing methods disclosed herein compared to the method disclosed in FIG. 2 as per the closest conventional method.

It can be noted that operating conditions (temperature, pressure, flow rate etc) used in these studied examples for the embodiments specifically disclosed herein were just a way of illustrating the embodiments herein, without imposing limitation to these operating conditions.

Embodiments according to the present disclosure realize at least some of the following advantages:

• • Significant savings in thermal energy and steam consumptions.
  • Provides the process flexibility to increase the ADC crude oil processing throughput.
  • Provides the crude processing methods to overcome the challenges of conventional methods. For example, energy and steam consumption in the method disclosed in FIG. 1 and high vacuum system load in the method disclosed in FIG. 2.
  • Provide process flexibility to handle the variation in the superheating temperature level of hydrocarbon and water vapor mix stream without affecting the VDC vacuum generation system load, thus leading to the smooth operation of VDC.
  • Energy savings will also decrease GHG emissions significantly from the crude distillation unit to the environment and make the crude oil processing cleaner and greener to meet the net zero emission target.
  • Reduction in energy and steam will reduce the equivalent crude import.