High VCM Coke Production via Feedstock Quenching
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Solution Overview
Problem
The production of high volatile combustible material (VCM) coke in petroleum coking processes is hindered by the need to operate coking drums at lower temperatures, which conflicts with achieving high heater outlet temperatures required for efficient cracking, affecting coke yield and throughput.
Innovation Solution
A process involving the heating of coker feedstock to a high temperature, followed by quenching with a medium to reduce the feedstock temperature before entering the coking drum, allowing for thermal cracking and producing coke with a VCM concentration of 13-50% by weight, while maintaining high heater outlet temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the heater outlet temperature is decreased to produce high VCM coke, then the VCM content in coke increases, but the cracking efficiency and throughput decrease
Solution Approach 1:
The heating and coking process is divided into two independent stages: (1) heating the feedstock to high temperature in the heater, and (2) quenching the heated feedstock before it enters the coking drum. This segmentation allows the heater to operate at high temperatures for efficient cracking while the quenching step reduces the temperature to promote high VCM coke formation, thereby resolving the contradiction between cracking efficiency and VCM content.
Solution Approach 2:
The feedstock is pre-heated to high temperature in the heater before entering the coking drum, and then quenching is applied as a preliminary action to reduce the temperature to the optimal range for high VCM coke formation. This preliminary temperature reduction allows the coking drum to operate under conditions that maximize VCM content without compromising the initial cracking efficiency achieved in the heater.
2Quantity of substance
If the coking drum temperature is reduced to increase VCM content, then high VCM coke is produced, but the heater outlet temperature must be reduced affecting throughput
Solution Approach 1:
A quench medium is introduced as an intermediary substance between the heater and the coking drum. This quench medium absorbs excess heat from the heated feedstock, rapidly reducing its temperature to the optimal range for high VCM coke formation. The quench medium acts as a thermal buffer, allowing the heater to maintain high outlet temperatures for efficient cracking while the coking drum operates at lower temperatures to maximize VCM content.
3Productivity
If high heater outlet temperatures are used for efficient cracking, then throughput increases, but the VCM content in coke decreases
Solution Approach 1:
The process segments the temperature control function between two distinct stages: the heater stage operates at high temperature to maximize cracking efficiency and throughput, while the quenching stage rapidly reduces the temperature to promote high VCM coke formation in the coking drum. This temporal and functional segmentation allows both high throughput and high VCM content to be achieved simultaneously.
Solution Approach 2:
The temperature parameter is dynamically changed through the quenching process. The feedstock enters the coking drum at a reduced temperature (after quenching) to promote high VCM content, while the heater operates at high temperatures for efficient cracking. This parameter change—achieved through controlled cooling—resolves the contradiction between throughput and VCM content.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the production of coke with desirable combustion properties and increased throughput by controlling the coking drum temperature through quenching, achieving higher VCM content and improved coke quality.
Implementation Method 1
contacting the heated coker feedstock with a quench medium to reduce a temperature of the heated coker feedstock
Implementation Method 2
the heated coker feedstock undergoes thermal cracking
Implementation Method 3
heating a coker feedstock to a coking temperature to produce a heated coker feedstock
Data Source
Figure 1
AI summary
A process and apparatus for improving the production of coke having a high volatile combustible material content are disclosed. The process may include, for example: heating a coker feedstock to a coking temperature to produce a heated coker feedstock; contacting the heated coker feedstock with a quench medium to reduce a temperature of the heated coker feedstock and produce a quenched feedstock; feeding the quenched feedstock to a coking drum; subjecting the quenched feedstock to thermal cracking in the coking drum to (a) crack a portion of the quenched feedstock to produce a cracked vapor product, and (b) produce a coke product having a volatile combustible material (VCM) concentration in the range from about 13 % to about 50 % by weight, as measured by ASTM D3175.