Zeolite Catalytic Cracking of PVC Waste for Low-Chlorine Hydrocarbons
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for recycling polyvinyl chloride (PVC) waste face challenges in maintaining uniform product properties and achieving high selectivity of useful components like C2 or C3 gas compounds and C5 to C9 gasoline oils, while also generating harmful substances like dioxin during incineration and being inefficient in resource recovery.
Innovation Solution
A catalytic cracking method using a zeolite catalyst with an average crystal size of 5 to 30 nm, supported by metals like Ni, Cu, or Fe, to pyrolyze PVC waste, producing a hydrocarbon mixture with high selectivity for olefin-based products and a solid residue that can be activated to produce activated carbon with a large specific surface area and pore volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical recycling method is used to recycle PVC waste, then the process is simple and suitable for processing large amounts of waste, but it is difficult to obtain recycled products with uniform properties
Solution Approach 1:
The patent replaces the mechanical recycling process with a chemical recycling process using catalytic cracking. Instead of physically mixing and reprocessing PVC waste mechanically, the invention uses chemical reactions (catalytic cracking) to decompose PVC into useful components, thereby achieving uniform product properties while maintaining process efficiency.
Solution Approach 2:
The patent changes the fundamental parameter of the recycling process from mechanical to chemical. By using catalytic cracking with specific catalysts and controlling reaction conditions (temperature, time, catalyst type), the process achieves consistent product properties that cannot be obtained through mechanical methods alone.
2Loss of substance
If pyrolysis process is used to chemically recycle PVC resin, then low molecular components can be recovered, but the selectivity of useful components like C2 or C3 gas compounds and C5 to C9 gasoline oils needs to be increased
Solution Approach 1:
The patent introduces a catalyst as an intermediary substance to mediate the pyrolysis reaction. The catalyst facilitates the decomposition of PVC and directs the reaction pathway to preferentially produce useful components such as C2-C3 gas compounds and C5-C9 gasoline oils, thereby improving selectivity without compromising the recovery of low molecular components.
Solution Approach 2:
The patent optimizes reaction parameters including temperature, time, and catalyst type to enhance the selectivity of useful components. By carefully controlling these parameters, the process maximizes the production of valuable hydrocarbons while still recovering low molecular components effectively.
3Ease of manufacture
If incineration is used to dispose of PVC waste, then the disposal process is straightforward, but harmful substances such as dioxin are generated during the incineration process
Solution Approach 1:
The patent converts the harmful incineration process into a beneficial chemical recycling process. Instead of burning PVC waste and generating dioxins, the invention uses catalytic cracking to transform the same waste material into useful chemical components, thereby eliminating harmful emissions while creating valuable products.
Solution Approach 2:
The patent replaces the thermal incineration process with a catalytic chemical reaction process. This substitution eliminates the formation of harmful combustion products like dioxins while still achieving effective waste treatment and resource recovery.
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
The method increases the selectivity of valuable hydrocarbon products and reduces chlorine content, enabling efficient recovery of C2 or C3 gas compounds and C5 to C9 gasoline oils, while producing activated carbon with enhanced properties.
Implementation Method 1
catalytic cracking of PVC waste... by catalytic cracking of PVC waste... in the presence of a zeolite catalyst... cracking the PVC waste in the presence of a zeolite catalyst
Implementation Method 2
zeolite catalyst with an average crystal size of 5 to 30 nm... zeolite catalyst has mesopores with a diameter of 5 to 30 nm
Implementation Method 3
By pyrolyzing the polyvinyl chloride resin under high temperature and oxygen-free conditions... pyrolyzing PVC waste in the presence of a zeolite catalyst to obtain a hydrocarbon mixture
Implementation Method 4
activating the solid residue formed according to the PVC catalytic cracking process... producing activated carbon with a high specific surface area and pore volume
Data Source
AI summary
A method for catalytic cracking of PVC waste using a zeolite catalyst to obtain a hydrocarbon mixture of gas components that are useful resources. The catalytic cracking method has high selectivity of useful components and can lower the content of chlorine, a harmful component.