Plastic Waste Hydrocracking for Polypropylene and Base Oil
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for recycling polyethylene and polypropylene waste plastics are inefficient, producing low-quality fuel components and are not scalable to address the growing environmental issue of single-use plastics, with chemical recycling via pyrolysis being limited in quantity and quality.
Innovation Solution
A continuous process integrating waste plastics with petroleum feedstock, passing the blend through a refinery hydrocracking unit to produce high-quality hydrocarbons, including polypropylene, gasoline, jet fuel, and base oil, while minimizing energy consumption and maintaining refinery operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pyrolysis is used to convert waste plastics to fuel, then chemical recycling is achieved, but the quality of fuel components is poor and quantity is limited
Solution Approach 1:
The invention changes the processing parameters by using hydrocracking conditions (temperature, pressure, catalyst) instead of pyrolysis, transforming the chemical reactions to produce high-quality hydrocarbons suitable for blending in transportation fuels while enabling processing of large volumes of waste plastic
Solution Approach 2:
The invention introduces a blend of waste plastic with petroleum feedstock as an intermediary step before hydrocracking. This blend allows the waste plastic to be processed through existing refinery hydrocracking units, leveraging the catalyst and reaction conditions to produce quality fuel components while handling large quantities
2Productivity
If large volumes of waste plastic are processed, then environmental impact is reduced, but product quality becomes too poor for fuel blending
Solution Approach 1:
The invention makes the waste plastic feedstock universal by blending it with petroleum feedstock to create a combined feed that can be processed in existing refinery hydrocracking units. This multi-functional approach allows simultaneous processing of large volumes while maintaining product quality suitable for transportation fuel blending
Solution Approach 2:
By changing the processing method from pyrolysis to hydrocracking with catalyst and hydrogen, the invention transforms the chemical reactions to produce high-quality hydrocarbons even from large volumes of waste plastic, enabling both high productivity and high product quality
3Productivity
If waste plastic is blended with petroleum feedstock, then processing capacity is increased, but energy consumption increases
Solution Approach 1:
The invention uses the hydrogen and heat already present in the refinery hydrocracking process to process the waste plastic blend. The petroleum feedstock serves as both a processing aid and energy source, providing hydrogen for hydrocracking reactions and heat for maintaining reaction temperature, thereby reducing additional energy requirements
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
Achieves a circular economy by efficiently recycling waste plastics into high-value products with quality comparable to virgin materials, reducing environmental impact and energy consumption, and producing clean fuels with lower carbon footprints.
Implementation Method 1
passing the blend through a refinery hydrocracking unit to produce high-quality hydrocarbons
Implementation Method 2
refinery hydrocracking unit to produce high-quality hydrocarbons
Data Source
AI summary
Provided is a continuous process for converting waste plastic into recycle for polypropylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene and preparing a stable blend of petroleum and the selected plastic. The amount of plastic in the blend comprises no more than 20 wt. % of the blend. The blend is passed to a refinery hydrocracking unit. A liquid petroleum gas C3 olefin/paraffin mixture is recovered from the hydrocracking unit. The C3 paraffins and C3 olefins are separated into different fractions with the C3 olefin fraction passed to a propylene polymerization reactor, and the C3 paraffin fraction passed optionally to a dehydrogenation unit to produce additional propylene. A heavy fraction can also be recovered from the hydrocracking unit and passed to an isomerization dewaxing unit to prepare base oil.