Mixed Waste Plastic Oil Valorization via Guard Bed and HZSM-5 USY Cracking
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Solution Overview
Problem
The integration of 100% mixed waste plastic pyrolysis oil into catalytic cracking processes is limited by high coke formation and the production of less valuable heavier products, such as fuel oil and tar.
Innovation Solution
A process involving the catalytic cracking of a feed stream containing mixed waste plastic pyrolysis oil and hydrocarbons, using a guard bed to adsorb contaminants and a catalyst mixture of HZSM-5 and USY to produce light olefins and aromatics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 100% mixed waste plastic pyrolysis oil is used in catalytic cracking processes, then waste plastic utilization is maximized, but coke formation increases and heavier products are produced
Solution Approach 1:
A guard bed containing adsorbent material is introduced as an intermediary component between the waste plastic pyrolysis oil and the catalytic cracking catalyst. The guard bed adsorbs harmful contaminants including coke precursors, metals (Fe, Ni, Cu, Mn), and other impurities from the pyrolysis oil before it contacts the cracking catalyst, thereby preventing coke formation and protecting the catalyst while still allowing the waste plastic to be processed
Solution Approach 2:
The harmful contaminants and coke precursors are extracted from the waste plastic pyrolysis oil stream through the guard bed adsorbent before the main catalytic cracking process. This extraction removes the harmful factors that would otherwise cause coke formation and catalyst deactivation, allowing the useful components of the pyrolysis oil to proceed to the cracking stage
2Adaptability or versatility
If mixed waste plastic pyrolysis oil is used as cracker feed, then waste utilization is improved, but production of valuable light olefins decreases
Solution Approach 1:
The guard bed acts as a protective intermediary that allows the waste plastic pyrolysis oil to reach the catalytic cracking unit without being degraded by contaminants. By removing harmful metals and coke precursors upstream, the main cracking catalyst can operate at optimal conditions and produce high yields of valuable light olefins from the waste plastic feedstock
Solution Approach 2:
The guard bed performs preliminary purification of the waste plastic pyrolysis oil before it enters the catalytic cracking process. This preliminary action removes contaminants that would otherwise inhibit the cracking reaction or cause catalyst deactivation, ensuring that the main cracking process can proceed efficiently and produce maximum light olefin yield
3Adaptability or versatility
If mixed waste plastic pyrolysis oil is integrated into refinery FCU feed streams, then waste utilization increases, but production of heavier products increases
Solution Approach 1:
The guard bed serves as a protective intermediary that enables the integration of waste plastic pyrolysis oil into refinery FCU feed streams without causing excessive coke formation or catalyst deactivation. By removing harmful contaminants upstream, the system can process waste plastic and produce desired products including lighter olefins rather than just heavier products
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 achieves higher yields of light olefins and aromatics, comparable to those from vacuum gas oil or hydrotreated light oil feeds, while minimizing coke formation and producing more valuable naphtha range components.
Implementation Method 1
passing the waste plastic pyrolysis oil through a guard bed configured to adsorb one or more of arsenic, lead, vanadium, silicon, chlorine, bromine, and fluorine components present in the waste plastic pyrolysis oil
Implementation Method 2
feeding the combined feed stream to a fluid catalytic cracking unit containing a catalytic cracking catalyst to yield a hydrocarbon product stream including a mixture of light olefins and aromatics
Data Source
AI summary
The disclosure provides processes and systems for fluid catalytic cracking of feed streams including hydrocarbons and varying amounts of mixed waste plastic oil to produce valuable petroleum products, such as light olefins and aromatics. The processes generally include providing a waste plastic pyrolysis oil, treating the waste pyrolysis oil reduce a content of one or more of silicon, chlorine, nitrogen, sulfur, and higher olefin components, providing a hydrocarbon stream, combining the hydrocarbon stream with the waste plastic pyrolysis oil to provide a combined feed stream, and feeding the combined feed stream to a fluid catalytic cracking unit having a catalytic cracking catalyst containing a mixture of HZSM-5 and USY.