Description:FIELD OF THE INVENTION
The present disclosure relates to the domain of Delayed Coker units of petroleum refinery, specifically focusing on a method and system for reducing coke yield and enhancing distillate yield in delayed coking operations.
BACKGROUND OF THE INVENTION
Petroleum refineries play a crucial role in producing a diverse range of products derived from crude oil. The distillation process is employed to separate crude oil into fractions with varying boiling points. Among these, liquefied petroleum gas (LPG) stands as the most volatile product, while higher boiling fractions yield desirable distillate liquids, such as gasoline, jet fuel, diesel fuel, and fuel oil. The residual fraction called vacuum residue, remaining after distillation, undergoes processing through a delayed Coker unit. The delayed coking process involves heating the residual oil feed to its thermal cracking temperature in a furnace with multiple parallel passes, leading to the production of various fractions of coker gas oil and petroleum coke.
Delayed coking is a common unit process in many petroleum refineries, with larger units featuring tandem pairs of drums. These drums, often reaching diameters of up to 10 meters and heights 4-5 times their diameter, are integral to the coking operation. The yield of coke from the delayed coking process typically ranges from 18 to 30 percent by weight of the feedstock residual oil, influenced by factors like the composition of the feedstock and various operating variables. Many refineries globally produce substantial amounts of petroleum coke daily, ranging from 2,000 to 3,000 tons or even more.
Traditionally, delayed coking has been employed as a method to convert low-value residues into more valuable liquid and gas products, with the resulting coke considered a low-value by-product. The yield of the delayed coker unit is influenced by parameters such as coke drum pressure, recycle rate, heater coil outlet temperature, velocity steam rate, and coking cycle time. Manipulating these process parameters, such as employing a low recycle ratio or maintaining low coke drum pressure during operation, has been recognized as a means to reduce coke yield in delayed coking.
Different additives have been experimented with in previous attempts to decrease coke yield in the Delayed Coking process. In U.S. Pat. No. 4,378,288, the utilization of free radical inhibitors such as benzaldehyde, nitrobenzene, aldol, sodium nitrate, etc., has been disclosed. These additives are applied at a dosage ranging from 0.005 to 10.0 wt % of the feedstock, primarily comprising Vacuum tower bottom, Reduced crude, Thermal tar, or a blend thereof. Notably, the additives in this patent exclusively consist of liquid-phase additives.
U.S. Pat. No. 4,394,250 has revealed the utilization of additives, including cracking catalysts such as silica, alumina, bauxite, silica-alumina, zeolites, acid-treated natural clays, and hydrocracking catalysts like metal oxides or sulfides of groups VI, VII, or VIII. These additives are applied in the presence of hydrogen at a dosage ranging from 0.1 to 3.0 wt % of the feedstock. Importantly, the additive is brought into contact with the feedstock before its introduction into the coke drum. The hydrocarbon feedstock employed in Delayed Coking encompasses materials such as shale oil, coal tar, reduced crude, residuum from thermal or catalytic cracking processes, and hydro-treated feedstocks.
Likewise, in US patent publication No. 2009/0209799, there is a disclosure of using FCC catalysts, zeolites, alumina, silica, activated carbon, crushed coke, calcium compounds, Iron compounds, FCC E-cat, FCC spent cat, seeding agents, hydrocracker catalysts. The dosage of these additives is specified as being less than 15% of the feed, predominantly applied to a suitable hydrocarbon feedstock commonly used in Delayed Coker operations.
In US Patent publication No. 2009/0209799, the superiority of injecting additives into the Coker drum over mixing them with the feed has been asserted. The majority of patents have unveiled the utilization of catalysts in both liquid and solid phases, generally categorizing them as free radical inhibitors, free radical removers, free radical accelerators, stabilizers, and cracking catalysts.
In US Patent Application No: US 4455219 reveals a method for reducing coke yield in a Delayed Coker by replacing a portion of the conventional recycle with a lower boiling range material.
Prior methods aimed at reducing coke yield involved incorporating additives such as free radical inhibitors and cracking catalysts, either directly into the coke drum or by mixing them with the feedstock. Although these methods exhibited potential, they frequently necessitated modifications to the feed composition, leading to undesirable properties in the final residue and products. Moreover, the economic feasibility of these processes was sometimes compromised due to the costs associated with these additives.
In the view of the foregoing discussion, it is clearly shown that there is a need of an invention approach for reducing coke yield by optimizing critical process parameters. A need exists to provide a solution for reducing coke yield and to implementing the same in a large-scale operational unit.
SUMMARY OF THE INVENTION
The present disclosure relates to a method and system for reducing coke yield and enhancing distillate yield in delayed coking operations. The current invention primarily aims to decrease coke yield and enhance distillate yield in the coking process by optimizing the critical process conditions. The focus is on achieving the desired outcomes through an innovative implementation of changes without introducing any process risks. In the conventional setup, the after-quench temperature of the coke drum vapor overhead line, extending from the top of the coke drum to the fractionator, is maintained at 423?. This temperature is controllable by using quench oil located upstream. The quench oil is essential to prevent coking within the vapor line by keeping the inner surface of the pipe continuously wet. The quench gas oil serves to reduce the temperature of the hot vapors and condense the heaviest molecules. The resulting liquid maintains the inside surface of the pipeline continuously wet, preventing coke formation, which could otherwise adversely impact unit operation. Preventing coke formation is crucial for maintaining lower pressure in the coke drum, ultimately reducing coke yield and increasing liquid yield. The after-quench temperature in the coke drum overhead is directly controlled by quench oil, which consists of hot Coker gas oil or blowdown quench oil through a complex logic. This temperature is typically fixed for every delayed Coker operation. The invention explores the feasibility of optimizing this after-quench temperature and the means to implement it without compromising the reliability of the entire process unit. A lower after-quench temperature is achieved by adjusting the flow of quench oil. Excessive quenching leads to a lower vapor line temperature, resulting in reduced liquid yields and potentially affecting unit feed rates. Conversely, insufficient quenching, operating the coke drum at a higher vapor line temperature, may lead to a vapor line devoid of liquid, causing a Coker shutdown due to coke accumulation. This invention introduces an innovative approach to strike a delicate balance between minimizing coke yield and preventing excessive drum pressure.
The present disclosure provides a method for reducing coke yield and enhancing distillate yield in delayed coking operations. The method comprises: feeding a vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU) to a main fractionator; passing the vacuum residue through a plurality of coker drums and a furnace to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions; heating the vacuum residue feed in the furnace to produce coke vapors introducing heavy coker gas oil (HCGO) into a coke drum vapor line to elevate the after quench temperature of coke vapors; elevating the after quench temperature by approximately 3 to 10 ?, and more specifically by 4 to 6 ?; monitoring and controlling the temperature of the coke vapors downstream of the quenching process to optimize the reduction of coke yields and enhance distillate yield in the coking process.
The present disclosure also seeks to provide a system for reducing coke yield and enhancing distillate yield in delayed coking operations. The system comprises: a main fractionator configured to receive vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU); a plurality of coker drums and a furnace arranged to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions; a flow control valve (CV valve) for controlling the flow of quench oil; a means for introducing heavy coker gas oil (HCGO) into the coke drum vapor line to increase the after quench temperature of coke vapors, wherein the introduction of HCGO increases the quenching temperature by approximately 3-10 ?, more specifically 4 to 6 ?; a Resistance Temperature Detector (RTD) and temperature controller positioned approximately 40 meters downstream in the same header at an elevation of 21 meters from grade for highly reliable temperature control, wherein the location mitigates inaccuracies caused by coke buildup on RTDs.
In an embodiment, the means for introducing HCGO is configured to maintain the after-quench temperature within a range of 423 °C to 426 °C.
In an embodiment, the system further comprises optimization means for adjusting the flow of quench oil based on operational parameters to ensure optimal quenching and vapor line temperature control.
In an embodiment, the means for introducing HCGO and the flow control valve are integrated into a control system for automated operation and control of the delayed coking process.
An objective of the present disclosure is to provide a method and system for reducing coke yield and enhancing distillate yield in delayed coking operations.
Another objective of the invention is to reduce coke yield in the coking process by optimizing the after-quench temperature of the coke drum vapor overhead line through innovative adjustments in the flow of quench oil.
Another objective of the invention is to enhance distillate yield by identifying critical process conditions that allow for efficient control of the after-quench temperature, ensuring the prevention of coke formation and maintaining optimal unit operation.
Another objective of the invention is to explore the feasibility of dynamically adjusting the after-quench temperature, providing a flexible approach that minimizes coke yield without compromising the reliability of the overall process unit.

Another objective of the invention is to strike a delicate balance between preventing excessive drum pressure and optimizing liquid yields, thus contributing to the efficiency and stability of the coking process.
Yet, another objective of the invention is to implement changes in the after-quench temperature control logic to achieve a fine-tuned equilibrium, preventing shutdowns caused by coke accumulation in the vapor lines while maintaining operational integrity and maximizing liquid product output.
To further clarify advantages and features of the present disclosure, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
BRIEF DESCRIPTION OF FIGURES
These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
Figure 1 illustrates a flow chart of a method for reducing coke yield and enhancing distillate yield in delayed coking operations in accordance with an embodiment of the present invention;
Figure 2 illustrates a block diagram of a system for reducing coke yield and enhancing distillate yield in delayed coking operations in accordance with an embodiment of the present disclosure; and
Figure 3 illustrates a Schematic diagram showing the coke drum vapor line temperature control in accordance with an embodiment of the present disclosure.
Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily been drawn to scale. For example, the flow charts illustrate the method in terms of the most prominent steps involved to help to improve understanding of aspects of the present disclosure. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

DETAILED DESCRIPTION:
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
It will be understood by those skilled in the art that the foregoing general description and the following detailed description are exemplary and explanatory of the invention and are not intended to be restrictive thereof.
Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Thus, appearances of the phrase “in an embodiment”, “in another embodiment” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.
The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method. Similarly, one or more devices or sub-systems or elements or structures or components proceeded by "comprises...a" does not, without more constraints, preclude the existence of other devices or other sub-systems or other elements or other structures or other components or additional devices or additional sub-systems or additional elements or additional structures or additional components.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings.
In the delayed coking process, heavy liquid hydrocarbons undergo thermal decomposition, resulting in the production of gas, liquid streams with varying boiling ranges, and coke. The objective is to minimize the production of coke, considered a low-value by-product, while concurrently optimizing liquid yields, which are of higher value.
The present invention is beneficial for improving the efficiency of Delayed Coker units by addressing the challenge of reducing coke yields during delayed coking operations. In conventional setups, the process involves the thermal decomposition of heavy liquid hydrocarbons, resulting in the production of gas, liquid streams with various boiling ranges, and coke. The primary objective is to diminish the production of coke, considered a low-value by-product, while simultaneously maximizing the production of liquid yields, which hold higher value in the petroleum refining process.
The present invention optimizes a critical process parameter known as the "after quench temperature" of the coke drum vapors. By strategically adjusting this temperature through the use of quench oil, the invention prevents coking within the vapor line, ultimately reducing coke yield and increasing liquid yield. This delicate balance is crucial for maintaining lower pressure in the coke drum, ensuring optimal unit operation.
The invention addresses the limitations of conventional setups where coke drum vapor overhead lines operate at fixed temperatures. It introduces a methodology for optimizing the "after quench temperature" without compromising the reliability of the entire process unit. By experimenting with measures such as relocating the temperature measurement point and adjusting quench rates, the invention demonstrates a significant reduction in coke yield. Overall, the innovation proves to be a valuable approach for enhancing the efficiency of delayed coking processes in large-scale operating units.
Figure 1 illustrates a flow chart of a method (100) for reducing coke yield and enhancing distillate yield in delayed coking operations in accordance with an embodiment of the present invention.
Referring to figure 1, the method (100) includes plurality of steps as described below.
At step (102), the method (100) includes feeding a vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU) to a main fractionator.
At step (104), the method (100) includes passing the vacuum residue through a plurality of coker drums and a furnace to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions.
At step (106), the method (100) includes heating the vacuum residue feed in the furnace to produce coke vapors introducing heavy coker gas oil (HCGO) into a coke drum vapor line to elevate the after quench temperature of coke vapors.
At step (108), the method (100) includes elevating the after quench temperature by approximately 3 to 10 ?, and more specifically by 4 to 6 ?.
At step (110), the method (100) includes monitoring and controlling the temperature of the coke vapors downstream of the quenching process to optimize the reduction of coke yields and enhance distillate yield in the coking process.
In an embodiment, the method (100) further comprises regulating the flow of coke vapors using a flow control valve.
In an embodiment, said Monitoring and controlling the temperature comprises measuring temperature of the vapor within the coke drum vapor line at a relocated position using a Resistance Temperature Detector (RTD) and temperature controller approximately 40 meters downstream in the same header at an elevation of 21 meters from grade ensuring highly reliable temperature control and mitigating inaccuracies caused by coke buildup on RTDs. The said monitoring and controlling the temperature comprises measuring temperature of the vapor within the coke drum vapor line at a relocated position using a Resistance Temperature Detector (RTD) and temperature controller substantially far away from conventional method of temperature measurement, ensuring highly reliable temperature control and mitigating inaccuracies caused by coke buildup on RTDs.
In an embodiment, the after quench temperature is maintained within a range of 423 °C to 426 °C.
In an embodiment, the coke drum vapor line temperature (after quench temperature) is optimized by controlling the HCGO quench rate and check on pressure drop across the vapor to achieve the desired reduction in coke yields and enhancement of distillate yields without impacting the reliability of the process unit.
In an embodiment, the method (100) further comprises controlling a flow of quench oil into a coke drum vapor line using a flow control valve (CV valve), wherein the flow of quench oil is adjusted based on operational parameters to ensure optimal quenching and vapor line temperature control.
Figure 2 illustrates a block diagram of a system (200) for reducing coke yield and enhancing distillate yield in delayed coking operations in accordance with an embodiment of the present disclosure.
Referring to figure 2, the system (200) includes a main fractionator (202) configured to receive vacuum residue from a vacuum distillation unit (VDU) (204) or a crude distillation unit (CDU) (206).
In an embodiment, a plurality of coker drums (208) and a furnace (210) are arranged to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions.
In an embodiment, a flow control valve (CV valve) (212) is configured for controlling the flow of quench oil.
In an embodiment, a means for introducing heavy coker gas oil (HCGO) (214) into the coke drum vapor line is used to increase the after quench temperature of coke vapors, wherein the introduction of HCGO increases the quenching temperature by approximately 3-10 ?, more specifically 4 to 6 ?.
In an embodiment, a Resistance Temperature Detector (RTD) (216) and temperature controller (218) are positioned approximately 40 meters downstream in the same header at an elevation of 21 meters from grade for highly reliable temperature control, wherein the location mitigates inaccuracies caused by coke buildup on RTDs.
In an embodiment, the means for introducing HCGO (214) is configured to maintain the after quench temperature within a range of 423 °C to 426 °C.
In an embodiment, the system (200) further comprises optimization means (220) for adjusting the flow of quench oil based on operational parameters to ensure optimal quenching and vapor line temperature control.
In an embodiment, the means for introducing HCGO (214) and the flow control valve (212) are integrated into a control system (222) for automated operation and control of the delayed coking process.
The disclosed invention outlines a process and method designed to reduce the coke yield in delayed cokers, consequently enhancing distillate yields without the addition of foreign materials to the feed vacuum residue. The key innovation involves increasing the after quench temperature of coke vapors through the utilization of heavy coker gas oil (HCGO). This process is executed by elevating the quench temperature by approximately 3-10 ?, with a more specific range of 4 to 6 ?. Importantly, these changes are implemented while ensuring the reliability and safety of the overall process unit. The inventive approach presents a comprehensive solution for optimizing delayed coker performance and maximizing liquid distillate production.
The invention optimizes the coking process by reducing coke yield and enhancing distillate yield. This is achieved by identifying critical process conditions and implementing innovative changes without introducing process risks. The key innovation involves adjusting the "after quench temperature" of the coke drum vapor overhead line, a controllable temperature using quench oil. This optimization prevents coking within the vapor line, maintains lower pressure in the coke drum, and increases liquid yield. The invention aims to find a delicate balance in the quench temperature to minimize coke yield while avoiding excessive drum pressure, providing a novel and efficient approach to improve the coking process.
To implement this invention, a three-step strategy has been devised:
Step-1: The initial innovation aimed to enhance the reliability of the "after quench temperature." In the conventional setup, this temperature is typically measured immediately at the outlet of the coke drum, positioned at an elevation of approximately 62 meters from the ground. However, this location is susceptible to coke deposits, resulting in unreliable measurements and suboptimal operations. To address this issue, the point of measurement was strategically relocated to a new position, ensuring a highly reliable temperature measurement over an extended period.
The positioning of a novel Resistance Temperature Detector (RTD) and temperature controller was moved approximately 40 meters downstream within the same header, situated at an elevation of 21 meters from the ground. This relocation guarantees exceptionally reliable temperature control, effectively addressing inaccuracies arising from coke buildup on the RTDs (Resistance Temperature Detectors).
Step-2: Following the attainment of reliable temperature monitoring, the subsequent challenge was to develop an implementation philosophy that mitigates any potential risks in a large operational unit. Achieving an optimal vapor line overhead temperature is a intricate task that necessitates experimentation. The novel setup emphasizes experimenting with elevated temperatures, specifically at 426°C, which is 3°C higher than the base temperature of 423°C at the newly identified measurement point.
In a pioneering approach, the experiment at elevated temperatures was selectively conducted in only one of the four coke drums. The line condition was then physically verified against the process data. This unique methodology instilled a significant level of confidence in conducting the experiment, ultimately leading to its successful implementation.
Step-3: Systematic experimental data was generated at two distinct temperatures (423°C and 426°C), uncovering a significant shift towards lower coke yields.
Experimental Result: The innovative steps, such as relocating the temperature measurement point, elevating the "after quench temperature," and methodically conducting experiments on a large operating unit, coupled with the optimization of quench rates, have shown substantial reductions in coke yield. These results affirm the effectiveness of the proposed approach in improving the overall efficiency of the coking process.
In an embodiment, plurality of examples of the invention are illustrated below,
Example 1:
Experiment data of Unit Product yields at 423 °C and 424°C after Quench Temp.
(Time Basis -24 Hours)
Parameters UOM Coke drum after Quench Temperature @ 423 °C Coke drum after Quench Temperature @ 424 °C Difference
Unit Throughput TPH 305.75 306.53 0.78
Unit Feed CCR Wt% 23.58 23.53 -0.05
H2S in Sour Water & Amine Wt% 1.02 1.01 -0.01
Fuel Gas + H2S Wt% 4.54 4.51 -0.03
Liquid Petroleum Gas(LPG) Wt% 2.91 2.90 0
Naphtha Wt% 13.92 13.75 -0.17
Light coke Gas oil (LCGO ) Wt% 25.77 25.48 -0.29
Heavy Coke Gas Oil (HCGO ) Wt% 21.9 22.63 0.73
Coke Factor - 1.27 1.26 -0.01
Petroleum Coke (Pet coke) Wt% 29.94 29.69 -0.24

Example 2:
Experiment data of Unit Product yields at 423 °C and 425 °C after Quench Temp.
(Time Basis -24 Hours)
Parameters UOM Coke drum after Quench Temperature @ 423 °C Coke drum after Quench Temperature @ 425 °C Difference
Unit Throughput TPH 305.75 307.31 1.56
Unit Feed CCR Wt% 23.58 23.47 -0.11
H2S in Sour Water & Amine Wt% 1.02 1.01 -0.01
Fuel Gas + H2S Wt% 4.54 4.49 -0.05
Liquid Petroleum Gas(LPG) Wt% 2.91 2.90 -0.01
Naphtha Wt% 13.92 13.59 -0.33
Light coke Gas oil (LCGO ) Wt% 25.77 25.2 -0.57
Heavy Coke Gas Oil (HCGO ) Wt% 21.9 23.35 1.45
Coke Factor - 1.27 1.26 -0.01
Petroleum Coke (Pet coke) Wt% 29.94 29.45 -0.49

Example 3:
Experiment data of Unit Product yields at 423°C and 426 °C after Quench Temp.
(Time Basis -24 Hours)
Parameters UOM Coke drum after Quench Temperature @ 423 0C Coke drum after Quench Temperature @ 426 0C Difference
Unit Throughput TPH 305.75 308.09 2.34
Unit Feed CCR Wt% 23.58 23.42 -0.16
H2S in Sour Water & Amine Wt% 1.02 1.00 -0.02
Fuel Gas + H2S Wt% 4.54 4.46 -0.08
Liquid Petroleum Gas(LPG) Wt% 2.91 2.90 -0.01
Naphtha Wt% 13.92 13.42 -0.50
Light coke Gas oil (LCGO ) Wt% 25.77 24.91 -0.86
Heavy Coke Gas Oil (HCGO ) Wt% 21.9 24.08 2.18
Coke Factor - 1.27 1.25 -0.02
Petroleum Coke (Pet coke) Wt% 29.94 29.21 -0.73

The reported readings represent the average of 10 days of daily measurements. The observations clearly indicate that elevating the quenching temperature from 423 °C to 426 °C leads to a significant reduction in coke production, consequently boosting the production of liquid distillates, primarily HCGO. This change corresponds to an approximate 2.5% reduction in coke yield. For delayed coker units operating with throughputs in the range of a few million tons per annum, the derived benefits translate into substantial financial gains.
Figure 3 illustrates a Schematic diagram showing the coke drum vapor line temperature control in accordance with an embodiment of the present disclosure.
Referring to figure 3, the shown Schematic diagram represents a system that is designed for reducing coke yields and enhancing distillate yield in delayed coking operations. It features a main fractionator receiving vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU), along with multiple coker drums and a furnace for thermal cracking. Key components include a flow control valve for quench oil, a mechanism introducing heavy coker gas oil (HCGO) into the coke drum vapor line to increase after quench temperature, and a Resistance Temperature Detector (RTD) with a temperature controller for precise temperature control downstream. This prevents inaccuracies caused by coke buildup on RTDs. The introduction of HCGO elevates quenching temperatures by 3-10 ?, specifically 4 to 6 ?. The system ensures the after quench temperature remains within the optimal range of 423 °C to 426 °C. Additionally, an optimization means adjusts the quench oil flow based on operational parameters, and the integration of HCGO introduction and the flow control valve into a control system enables automated operation and control of the delayed coking process.
The drawings and the forgoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, orders of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts necessarily need to be performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples. Numerous variations, whether explicitly given in the specification or not, such as differences in structure, dimension, and use of material, are possible. The scope of embodiments is at least as broad as given by the following claims.
Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any component(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or component of any or all the claims. , Claims:1. A method for reducing coke yields and enhancing distillate yield in delayed coking operations, comprising the steps of:
feeding a vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU) to a main fractionator;
passing the vacuum residue through a furnace and a plurality of coker drums to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions;
heating the vacuum residue feed in the furnace to produce coke vapors introducing heavy coker gas oil (HCGO) into a coke drum vapor line to elevate the after quench temperature of coke vapors;
elevating the after quench temperature by approximately 3 to 10 ?, and more specifically by 4 to 6 ?;
monitoring and controlling the temperature of the coke vapors downstream of the quenching process to optimize the reduction of coke yields and enhance distillate yield in the coking process.

2. The method as claimed in claim 1, wherein said Monitoring and controlling the temperature comprises measuring temperature of the vapor within the coke drum vapor line at a relocated position using a Resistance Temperature Detector (RTD) and temperature controller approximately 40 meters downstream in the same header at an elevation of 21 meters from grade ensuring highly reliable temperature control and mitigating inaccuracies caused by coke buildup on RTDs.

3. The method as claimed in claim 1, wherein the after quench temperature is maintained within a range of 423 °C to 426 °C.

4. . The method as claimed in claim 1, wherein the coke drum vapor line temperature (after quench temperature) is optimized by controlling the HCGO quench rate and check on pressure drop across the vapor to achieve the desired reduction in coke yields and enhancement of distillate yields without impacting the reliability of the process unit.

5. The method as claimed in claim 1 further comprising controlling a flow of quench oil into a coke drum vapor line using a flow control valve (CV valve), wherein the flow of quench oil is adjusted based on operational parameters to ensure optimal quenching and vapor line temperature control.

6. A system for reducing coke yields and enhancing distillate yield in delayed coking operations, comprising:
a main fractionator configured to receive vacuum residue from a vacuum distillation unit (VDU) or a crude distillation unit (CDU).
a plurality of coker drums and a furnace arranged to thermally crack the vacuum residue to produce coke vapors and lighter hydrocarbon fractions;
a flow control valve (CV valve) for controlling the flow of quench oil;
a means for introducing heavy coker gas oil (HCGO) into the coke drum vapor line to increase the after quench temperature of coke vapors, wherein the introduction of HCGO increases the quenching temperature by approximately 3-10 ?, more specifically 4 to 6 ?;
a Resistance Temperature Detector (RTD) and temperature controller positioned approximately 40 meters downstream in the same header at an elevation of 21 meters from grade for highly reliable temperature control, wherein the location mitigates inaccuracies caused by coke buildup on RTDs.

7. The system as claimed in claim 6, wherein the means for introducing HCGO is configured to maintain the after quench temperature within a range of 423 °C to 426 °C.

8. The system as claimed in claim 6, further comprising optimization means for adjusting the flow of quench oil based on operational parameters to ensure optimal quenching and vapor line temperature control.

9. The system as claimed in claim 6, wherein the means for introducing HCGO and the flow control valve are integrated into a control system for automated operation and control of the delayed coking process.

10. The system as claimed in claim 6, wherein the coke drum vapor line temperature (after quench temperature) is optimized by controlling the HCGO quench rate and check on pressure drop across the vapor to achieve the desired reduction in coke yields and enhancement of distillate yields without impacting the reliability of the process unit.