Silicone Antifoam Injection Control in Delayed Coking Drums
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Solution Overview
Problem
Current petroleum coking processes face challenges in controlling foaming in coke drums, leading to potential blockages and catalyst poisoning, which requires excessive use of silicone-based anti-foam agents, increasing costs and reducing liquid production.
Innovation Solution
Using highly aromatic hydrocarbon liquids as a carrier fluid for PDMS injection, reducing the concentration of PDMS and employing a carrier oil with an aromatic concentration greater than 90%, such as clarified slurry oil, to enhance foam drainage and minimize anti-foam agent usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silicone-based anti-foam agent is continuously injected to control foaming, then foaming is controlled, but costs increase and liquid production decreases
Solution Approach 1:
The patent implements periodic injection of anti-foam agent based on foam level detection rather than continuous injection. The system monitors foam height and triggers injection only when foam exceeds a predetermined level, creating a periodic action pattern that maintains foam control while minimizing agent consumption and preserving liquid production.
Solution Approach 2:
The patent employs a feedback control system where foam level is continuously monitored and this information is used to control the timing and amount of anti-foam agent injection. The feedback mechanism ensures that injection occurs only when necessary, optimizing both foam control and liquid production by avoiding excessive agent use.
2Reliability
If silicone-based anti-foam agent is continuously injected to control foaming, then foaming is controlled, but costs increase
Solution Approach 1:
The system transitions from continuous to periodic injection by monitoring foam levels and triggering injection only when foam exceeds predetermined thresholds. This periodic action significantly reduces the total quantity of anti-foam agent consumed while maintaining effective foam control.
Solution Approach 2:
The system enables self-regulated anti-foam agent injection through automatic foam level detection and control. The process monitors its own foam conditions and autonomously determines when injection is necessary, eliminating the need for continuous injection and reducing agent consumption.
3Object-generated harmful factors
If higher temperature is applied to reduce surface tension and viscosity, then foaming is reduced, but energy consumption increases and product properties may be affected
Solution Approach 1:
The patent introduces anti-foam agent as an intermediary substance that addresses the foaming problem without requiring temperature increase. The anti-foam agent acts as a mediator that reduces surface tension and stabilizes foam bubbles chemically, providing an alternative to thermal energy input.
Solution Approach 2:
The patent replaces the mechanical/thermal approach (heating to reduce viscosity and surface tension) with a chemical approach (anti-foam agent injection). This substitution eliminates the need for additional energy input while achieving the same foaming control objective.
4Reliability
If more vapor space is provided in the coke drum, then foam-over risk is reduced, but unit modifications are required and operating costs increase
Solution Approach 1:
The patent implements dynamic foam control through real-time monitoring and adaptive injection timing. The system adjusts anti-foam agent injection based on actual foam conditions during different stages of the drum cycle, providing flexible control without requiring static structural modifications to increase vapor space.
Solution Approach 2:
The patent changes the operational parameters (injection timing, injection amount, injection rate) rather than modifying the physical structure of the drum. By optimizing these parameters, the system achieves foam-over prevention without the need for unit modifications that would increase device complexity and capital 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 effectively controls foaming, reduces the amount of silicone-based anti-foam agent needed, and enhances liquid yield while improving coke material quality by modifying foam properties and extending the drainage period.
Implementation Method 1
Foaming is caused by higher surface tension and viscosity of the partially converted liquids in the coke drum
Data Source
AI summary
The current invention provides an improved petroleum coking process wherein the risk of silicone poisoning of units downstream of the coke drums is reduced. The method of the current invention controls the foam layer within the coke drum by injection of a silicone anti-foam agent in a highly aromatic carrier fluid such as slurry oil.