Thermal Cracking of Waste Plastics for Aromatics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The disposal of waste plastics poses environmental challenges, and existing methods like incineration and landfills are unsustainable, necessitating innovative processes that convert waste plastics into reusable feedstocks for plastic production, particularly to produce aromatics efficiently and sustainably.
Innovation Solution
A process involving the thermal cracking of waste plastics in the presence of steam, optimizing conditions such as coil outlet temperature and steam-to-feed ratio to maximize the production of aromatics like benzene, toluene, styrene, ethylbenzene, and xylenes, while extending the run duration of steam cracking operations and reducing fouling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If waste plastics are processed by incineration, then energy is produced, but atmospheric carbon emissions increase
Solution Approach 1:
The invention changes the processing parameters from high-temperature incineration to controlled thermal cracking at lower temperatures (800-870°C), transforming the chemical reactions from complete combustion to partial decomposition that produces aromatic hydrocarbons instead of CO2 emissions
Solution Approach 2:
The invention converts the harmful waste plastic material into valuable aromatic chemical building blocks through thermal cracking, transforming an environmental problem into a resource recovery opportunity that supports circular plastic processing
2Ease of manufacture
If waste plastics are discarded in landfills, then disposal is simple, but environmental pollution increases
Solution Approach 1:
The invention transforms the harmful waste plastic that would otherwise pollute landfills into valuable aromatic chemical building blocks through thermal cracking, converting an environmental burden into a useful resource for producing new plastics and chemicals
3Productivity
If steam cracking is performed at high temperature, then cracking efficiency increases, but coke formation and fouling increase
Solution Approach 1:
The invention optimizes the temperature parameter to a specific range (800-870°C) that balances cracking efficiency with minimal coke formation, and adjusts the steam-to-feed ratio (0.3-0.6) to suppress fouling while maintaining high aromatic production
Solution Approach 2:
The invention introduces steam as an intermediary substance that interacts with the waste plastic feedstock during thermal cracking, suppressing coke formation and fouling on reactor surfaces while maintaining high cracking efficiency and extending operational run duration
4Quantity of substance
If conventional steam cracking is used for waste plastics, then monomers are produced, but carbon efficiency towards aromatics is low
Solution Approach 1:
The invention changes the cracking parameters (temperature 800-870°C, steam-to-feed ratio 0.3-0.6) to optimize the product distribution towards aromatic hydrocarbons (benzene, toluene, xylenes) rather than just aliphatic monomers, maximizing carbon efficiency towards aromatics
Solution Approach 2:
The invention dynamically adjusts the steam-to-feed ratio (0.3-0.6) to control the cracking reactions and maximize aromatic yields from waste plastic feedstocks, optimizing carbon utilization efficiency
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 process enhances the carbon efficiency of aromatics production from waste plastics, promoting circular plastic processing, increasing aromatic yields, and sustaining operational efficiency by minimizing coke formation and fouling, thus addressing environmental concerns and economic viability.
Implementation Method 1
performing a thermal cracking operation in the presence of steam to obtain a cracked hydrocarbon stream D
Implementation Method 2
supplying the cracked hydrocarbon stream D to one or more separation units; performing a separation operation to obtain different streams comprising benzene, toluene, styrene, ethylbenzene and xylenes
Data Source
AI summary
The present invention relates to a process for the production of aromatics from waste plastics feedstocks comprising the steps in this order of: (a) providing a hydrocarbon stream A obtained by treatment of a waste plastics feedstock; (b) providing a hydrocarbon stream B; (c) supplying a feed C comprising a fraction of the hydrocarbon stream A and a fraction of the hydrocarbon stream B to a thermal cracker furnace comprising cracking coil(s); (d) performing a thermal cracking operation in the presence of steam to obtain a cracked hydrocarbon stream D; (e) supplying the cracked hydrocarbon stream D to one or more separation units; (f) performing a separation operation to obtain different streams comprising benzene, toluene, styrene, ethylbenzene and xylenes; wherein in step (d): ⋅ the coil outlet temperature is ≥800 and ≤80° C., preferably ≥830 and ≤870° C.; 7 and ⋅ the weight ratio of steam to feed C is >0.3 and <0.8, preferably >0.3 and <0.5. Such process allows for optimisation of the quantity of waste plastic material that finds its way back into products that are produced as outcome of the process. The higher that quantity is, i.e. the higher the quantity of chemical building blocks that are present in the waste plastic material that are converted to the produced products, the better the sustainability footprint of the process is. The process allows for circular utilisation of plastics.