Delayed Coking Drum Cycle Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Delayed coking systems face bottlenecks in throughput and product quality due to fluctuating feed compositions, inefficient liquid product recovery, drum damage from temperature swings, and limitations in maximum heater outlet temperature, leading to reduced product yield and increased VOC content.
Innovation Solution
The process involves a modified delayed coking system with alternating drum cycles, eliminating quenching and hydraulic decoking procedures, allowing higher coking temperatures, and utilizing a flash vessel and heat exchanger to recover heat and reduce waste water, enabling faster cycle times and improved product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If quenching and hydraulic decoking procedures are used, then coke product can be removed from drums, but cycle time is extended and drum damage occurs from temperature swings
Solution Approach 1:
The patent changes the temperature parameter by eliminating the quenching step that causes extreme temperature swings. Instead, the system maintains more stable temperatures through modified process conditions, allowing coke removal without thermal shock to the drums.
Solution Approach 2:
The patent extracts and eliminates the harmful quenching and hydraulic decoking steps from the process. By removing these steps, the system avoids drum damage while maintaining productivity through alternative coke removal methods.
2Productivity
If maximum heater outlet temperature is limited, then drum damage is reduced, but product yield decreases and VOC content increases
Solution Approach 1:
The patent changes multiple parameters simultaneously - increasing heater outlet temperature while modifying other process conditions (such as residence time, pressure, or feed composition) to compensate. This allows higher temperatures that improve yield and reduce VOC content without causing drum damage.
Solution Approach 2:
The patent applies preliminary actions to prepare the feed or system conditions before heating, allowing the use of higher temperatures without adverse effects. This might include pre-treatment of feedstock or preparation of the coking environment to enable safer high-temperature operation.
3Productivity
If alternating drum cycles are used, then continuous operation is maintained, but vapor feed composition fluctuates
Solution Approach 1:
The patent makes the system more universal by having both drums capable of operating in similar modes or by creating a system where the alternating cycles produce more consistent outputs. This might involve modifying both drums to have similar characteristics or adding control mechanisms that standardize the vapor feed regardless of which drum is active.
4Loss of energy
If heat recovery and waste reduction systems are added, then operating costs decrease, but device complexity increases
Solution Approach 1:
The patent recovers energy and materials that would otherwise be discarded - specifically heat from the coking process and water from quenching operations. By capturing and reusing these resources, the system reduces operating costs for energy and waste treatment.
Solution Approach 2:
The patent makes the system self-sufficient by using its own waste heat and water for process needs. The heat exchanger uses process heat for heating feed, and waste water is reused, reducing external utility requirements and operating costs.
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 significantly reduces cycle times, increases throughput, stabilizes vapor feed compositions, enhances liquid product yields and quality, decreases VOC content, and lowers operating costs while minimizing drum damage and waste production.
Implementation Method 1
a flash vessel wherein a heated petroleum feed stream will separate into a flash vapor product stream and a flash liquid product stream
Implementation Method 2
a heat exchanger through which the coke product from the coking drums will flow in solid form for recovering heat from the coke product
Implementation Method 3
The hot coke product is then conveyed to a heat exchanger for generating steam from refinery boiler feed water
Implementation Method 4
The liquid feed material is then pumped through the fired heater and into at least one coking drum
Implementation Method 5
The hot liquid material undergoes intensive thermal cracking and polymerization as it remains in the coking drum such that the liquid material is converted to cracked vapor and petroleum coke
Data Source
AI summary
A delayed coking process and apparatus which greatly shorten the required duration of the alternating drum fill and decoking cycles and eliminate the need to perform drum quenching, draining, unheading, hydraulic decoking, reheading, pressure testing, and warming procedures in the decoking cycle. In the inventive system, the decoking cycle preferably comprises simply a steamout stage and a coke product draining procedure. The coke product produced in the coking drums is a hot, solid, flowable material from which heat can be recovered for preheating the coker feed and/or producing steam.