Catalytic Cracking Reactor for Waste Plastic Ethylene Production
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Solution Overview
Problem
The production of ethylene and propene is limited by the scarcity of naphtha resources, and the recycling of waste plastic is hindered by the difficulty in automated sorting, resulting in low utilization rates and environmental pollution.
Innovation Solution
A method involving the pretreatment of waste plastic, mixing it with superheated steam, and feeding it into a catalytic cracking reactor, followed by a two-stage prewashing column for purification, hydrogenation, and steam cracking to maximize the yield of ethylene and propene, with recycled products enhancing the catalytic cracking process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If naphtha is used as raw material for ethylene production, then production process is simple, but production capacity is limited by raw material scarcity
Solution Approach 1:
The catalytic cracking reactor is designed to process multiple types of raw materials (waste plastic, naphtha, oil) through the same equipment and catalyst system, enabling the system to universally convert different carbon-containing materials into ethylene and other valuable products, thereby eliminating the limitation of naphtha scarcity
Solution Approach 2:
The invention changes the raw material parameters from traditional naphtha to waste plastic and other alternative feedstocks while adjusting catalytic cracking parameters (temperature, catalyst type, residence time) to optimize ethylene yield from these new raw materials, achieving high productivity without being constrained by naphtha availability
2Productivity
If waste plastic is recycled through conventional methods, then sorting and processing is required, but automated sorting is difficult and utilization rate is low
Solution Approach 1:
The invention extracts the sorting requirement from the recycling process by directly feeding mixed waste plastic into the catalytic cracking reactor where all plastic types are converted into gaseous products through thermal and catalytic cracking, eliminating the need for complex automated sorting equipment and manual classification
Solution Approach 2:
The invention changes the processing approach from physical sorting to chemical transformation, using catalytic cracking parameters (temperature, catalyst, residence time) to convert diverse plastic compositions into uniform gaseous products, thereby simplifying the process and increasing utilization rate
3Object-affected harmful factors
If waste plastic is treated by burying or burning, then disposal is achieved, but environmental pollution is caused
Solution Approach 1:
The invention converts the harmful waste plastic into beneficial products (ethylene, propylene, fuel gases) through catalytic cracking, transforming the environmental hazard into valuable chemical feedstocks and energy sources, thereby eliminating pollution while recovering energy and materials
Solution Approach 2:
The invention implements a feedback system where waste plastic is converted into gaseous products that can be further processed or used as fuel, creating a closed-loop system that eliminates environmental pollution while recovering energy and materials for productive use
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 method achieves a yield of 45-75% ethylene and propene from raw materials, along with 15-30% arene BTX, significantly improving the production capacity and reducing waste, while also addressing environmental concerns through efficient plastic recycling.
Implementation Method 1
the raw material is converted into waste residue and high-temperature oil and gas in the presence of a catalyst
Implementation Method 2
obtaining light distillate oil, heavy distillate oil, a gaseous product, and the like by cooling and purifying the high-temperature oil and gas using a two-stage prewashing column
Implementation Method 3
hydrogenating the heavy distillate oil in step S1, reforming alkene components in the light distillate oil
Implementation Method 4
feeding alkane components in the light distillate oil to a steam cracking device
Data Source
AI summary
Disclosed is a method for maximizing ethylene or propene production, the main steps thereof being: taking crude oil and distillate thereof, pre-processing urban mixed-waste plastics as raw material, then entering same into a catalytic cracking reactor, removing via a two-stage pre-wash tower and related separation, then cooling the reacted high-temperature oil and gas and removing impurities to obtain light and heavy distillate oils; performing a hydrogenation reaction operation on the heavy distillate oil; performing light distillate oil separation, performing a recombination operation on its olefins, its alkanes entering a steam cracking apparatus to produce rich ethylene, and its aromatic components being separated as by-products; the product of the described hydrogenation and recombination reaction and the steam-cracked distillate oil is recycled to the catalytic cracking reactor. In the production method of the present invention, the yield of ethylene and propene together is 45-75 m % of the raw material, and the yield of aromatics is 15-30 m % of the raw material; in particular, when using urban mixed-waste plastics as raw material, the ethylene or propene thus produced are used to produce new plastics by way of a conventional polymerization process, achieving the chemical recycling of waste plastics.