C4-C7 Pyrolysis Oil Cracking for Higher Olefin Yield
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Recycling non-biodegradable waste materials is economically challenging due to the need for expensive processing and different types of recycling processes, and pyoil cracking in gas furnaces leads to recombination of heavier hydrocarbons, tube fouling, and lower olefin yields.
Innovation Solution
A method involving the use of a cracker feedstock composition comprising recycle content pyrolysis oil (r-pyoil) with a C4 to C7 content of at least 35% by weight, which is not hydrotreated, and cracking it in a cracker furnace to produce an olefin-containing effluent stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If heavier hydrocarbons are cracked in a gas furnace, then olefin production is achieved, but recombination to heavier molecules and tube fouling occur
Solution Approach 1:
The patent applies parameter changes by controlling the residence time of hydrocarbons in the furnace at less than 0.5 seconds and maintaining specific temperature zones. This rapid processing prevents heavier hydrocarbons from recombining and fouling the tubes while still achieving effective cracking to produce olefins.
2Productivity
If pyoil is cracked in a gas furnace, then olefins are produced, but heavier hydrocarbons recombine to heavier molecules
Solution Approach 1:
The patent controls the cracking process by maintaining specific temperature parameters and residence time parameters. The furnace operates at temperatures that promote cracking while the residence time of less than 0.5 seconds prevents reverse reactions that would cause recombination to heavier molecules.
Solution Approach 2:
The patent employs dynamic control of the cracking process by continuously adjusting operating parameters such as feed rate, temperature distribution along the furnace length, and residence time. This dynamic optimization ensures high olefin yield while preventing composition instability and recombination.
3Adaptability or versatility
If a wide range of pyoil carbon numbers is processed, then feedstock flexibility is improved, but process control difficulty increases
Solution Approach 1:
The patent designs a universal cracking process that can handle a wide range of pyoil carbon numbers (C4-C7 and beyond) using the same furnace configuration. The process achieves multi-functionality by maintaining parameter ranges that are effective for different feedstock compositions without requiring separate processing lines or complex adjustments.
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
Enhances the cracking of pyoil and increases olefin yields while preventing tube fouling in gas furnaces, allowing for efficient processing of a wide range of pyoil carbon numbers.
Implementation Method 1
cracking the cracker feed stream in the cracking furnace to thereby form 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. Alternatively, the r-pyoil with a predominantly C4-C7 fraction can be fed to the cracker feed. The furnace can be a gas fed furnace, or split cracker furnace.