Blending Recycle Pyrolysis Oil in Cracker Feedstocks
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Solution Overview
Problem
The challenge lies in efficiently recycling waste materials, particularly non-biodegradable waste, due to the need for costly processing and the complexity of handling diverse waste types, as well as the limitations posed by pyrolysis oil (pyoil) in cracking processes, which can lead to overcracking and equipment fouling in crackers.
Innovation Solution
Incorporating a recycle content pyrolysis oil (r-pyoil) composition into cracker feedstocks, allowing for the production of olefins by combining r-pyoil with non-recycle hydrocarbon streams and cracking them in a cracker furnace, thereby reducing impurities and maintaining flexibility in fractionation, and enabling continuous feeding of pyoil without the need for campaigning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyoil is added to cracker feedstock, then recycling efficiency is improved, but overcracking and fouling occur reducing olefin yield
Solution Approach 1:
The patent changes the compositional parameters of the feedstock by limiting pyoil to ≤20 wt% and adjusting the carbon number distribution (C5-C22 range). This parameter optimization prevents overcracking while maintaining recycling benefits, resolving the contradiction between recycling efficiency and olefin yield
Solution Approach 2:
The patent creates a composite feedstock system combining pyoil with conventional hydrocarbon feedstocks (natural gasoline, reformate, etc.). This composite approach allows the benefits of pyoil recycling while diluting its harmful effects on cracker performance, thereby maintaining both recycling efficiency and olefin yield
2Productivity
If pyoil is added to cracker feedstock, then recycling efficiency is improved, but service time of cracker is reduced
Solution Approach 1:
The patent optimizes feedstock parameters by controlling pyoil content (≤20 wt%) and carbon number distribution (C5-C22) to prevent excessive coke formation and tube fouling. This parameter control extends cracker service time while maintaining recycling efficiency
Solution Approach 2:
By formulating a composite feedstock with pyoil blended with conventional hydrocarbons, the patent reduces the concentration of problematic pyoil components that cause fouling. This composite approach maintains recycling benefits while extending equipment service time
3Manufacturing precision
If separation equipment is used to fractionate pyoil, then cracking performance is improved, but cost and complexity increase
Solution Approach 1:
Instead of using complex separation equipment to fractionate pyoil, the patent extracts only the necessary portion (≤20 wt%) of pyoil components that are beneficial for cracking, leaving the heavier problematic components behind. This selective extraction achieves good cracking performance without requiring expensive separation equipment
Solution Approach 2:
The patent changes the approach from physical separation to compositional specification, defining feedstock by its carbon number range (C5-C22) and pyoil content (≤20 wt%). This parameter-based approach simplifies the process by eliminating the need for complex fractionation equipment while maintaining cracking performance
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 enhances recycling efficiency, reduces processing costs, and allows for the production of olefins with improved yield and service time in crackers, while promoting environmental sustainability by utilizing recycled materials.
Implementation Method 1
cracking them in a cracker furnace to provide an olefin-containing effluent stream
Data Source
AI summary
A hydrocarbon cracker stream is combined with recycle content pyrolysis oil to form a combined cracker stream and the combined cracker stream is cracked in a cracker furnace to provide an olefin-containing effluent. The r-pyoil can be fed to the cracker feed. More specifically the-pyoil is present in said feedstock in an amount of not more than 20% by weight, based on the total weight of the feedstock.