Co-Processing Polymeric Waste in Cokers for Circular Chemicals
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Solution Overview
Problem
Current methods for producing circular chemical products from polymeric waste are hindered by the high initial capital costs of dedicated processing systems and the need for a constant supply of waste feedstock, making it desirable to integrate polymeric waste co-processing into existing coker units to produce circular chemical products efficiently.
Innovation Solution
The method involves co-processing polymeric waste with conventional coker feedstocks in a coker to produce coker naphtha, which is then cracked to form olefins, and subsequently polymerized to produce circular polyolefins, utilizing existing coker infrastructure to reduce costs and increase efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dedicated processing systems are used for polymeric waste recycling, then production of circular chemical products is achieved, but initial capital costs increase substantially
Solution Approach 1:
The patent combines polymeric waste processing with an existing coker unit by integrating a pyrolysis system that feeds into the coker's existing cracking mechanism. The pyrolysis oil from polymeric waste is mixed with conventional coker feedstock and processed through the existing coker infrastructure, merging two separate processes (waste pyrolysis and coker operation) into a unified system that shares equipment and reduces capital costs.
Solution Approach 2:
The coker unit is designed to handle multiple feedstock types simultaneously - both conventional petroleum-based feedstocks and pyrolysis oil derived from polymeric waste. This multi-functionality allows the existing coker infrastructure to serve dual purposes: traditional hydrocarbon processing and circular chemical product production from waste, thereby avoiding the need for dedicated single-purpose processing systems.
2Reliability
If dedicated processing systems are used for polymeric waste recycling, then circular chemical products are produced, but constant supply of waste feedstock is required
Solution Approach 1:
The system merges polymeric waste feedstock with conventional coker feedstocks in a blended feedstream. This combination ensures that when polymeric waste supply fluctuates or is unavailable, the conventional feedstock maintains continuous operation of the coker unit, providing feedstock supply flexibility while still enabling circular chemical product production when waste is available.
Solution Approach 2:
The system allows variable composition of the feedstock mixture, adjusting the proportion of pyrolysis oil to conventional feedstock based on waste availability and market conditions. This parameter flexibility enables the process to adapt to changing feedstock supplies while maintaining stable operation and product quality.
3Device complexity
If polymeric waste is co-processed in cokers, then capital expenditures are reduced, but aromatic and sulfur content in coker naphtha increases
Solution Approach 1:
The system extracts and removes harmful components (aromatics and sulfur) from the coker naphtha through dedicated downstream processing units. These extraction processes separate the contaminants from the valuable chemical products, allowing the co-processing of polymeric waste in the coker while maintaining product quality specifications through subsequent purification steps.
Solution Approach 2:
The system converts the harmful aromatic and sulfur-containing compounds generated during co-processing into valuable by-products or uses them as feedstock for other processes. For example, sulfur-containing streams can be directed to sulfur recovery units, and aromatic-rich streams can be processed separately, thereby transforming what would be waste or contaminants into potential revenue streams.
4Device complexity
If polymeric waste is co-processed in cokers, then existing infrastructure is utilized, but processing efficiency may decrease
Solution Approach 1:
The system performs preliminary pyrolysis of polymeric waste outside the coker unit to convert it into pyrolysis oil, which has properties more suitable for coker processing. This pre-processing step breaks down the complex polymeric structures into smaller molecules that can be more efficiently cracked in the coker, thereby maintaining or even improving overall processing efficiency while utilizing existing infrastructure.
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 allows for the production of circular chemical products, such as polyolefins, by reducing the aromatic and sulfur content in coker naphtha, thereby increasing its value and efficiency in chemical production, while minimizing capital expenditures and ensuring a consistent feedstock supply.
Implementation Method 1
cracking at least a coker naphtha to form at least a cracking effluent
Implementation Method 2
polymerizing at least a portion of the olefins to form at least a polyolefin
Data Source
AI summary
Systems and methods are provided for integration of polymeric waste co-processing in cokers to produce circular chemical products from coker naphtha, including a method of producing circular chemical products comprising: providing a coker naphtha that is at least partially derived from polymeric waste, wherein the coker naphtha has a total halide content of about 1 wppm to about 0.5 wt %, a 2-3 ring aromatic content of about 0 wt % to about 5 wt %, and a sulfur content of about 750 ppm to about 2 wt %; and converting the coker naphtha into at least a polymer.