Waste Plastic Compression Shaping for Coke Oven Feed
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Solution Overview
Problem
Existing methods for recycling waste plastic in coke furnaces face challenges in maintaining coke quality due to issues with volatile ingredients, oily matter, and hydrogen chloride production, which affect coke strength and require expensive treatment facilities.
Innovation Solution
Melting waste plastic between 160° C to 250° C and compression shaping it to achieve an apparent density of 0.7 to 1.2 kg/liter, mixing it with coal in a coke oven, and treating gases with water or ammonia solutions to reduce volatile content and hydrogen chloride production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If waste plastic is mixed with coal in large amounts for dry distillation in coke ovens, then the recycling volume increases and treatment cost decreases, but the coke strength deteriorates due to high volatile ingredients and oily matter content
Solution Approach 1:
The patent applies preliminary action by pre-processing waste plastic through compression molding to create densified granular material before mixing with coal. This preliminary densification reduces the volume of volatile ingredients and oily matter, allowing larger mixing ratios (5-20% by mass) without compromising coke strength, thus resolving the contradiction between recycling volume and coke quality
Solution Approach 2:
The patent changes physical parameters of waste plastic by compressing it at temperatures between 50-200°C to achieve an apparent density of 0.40-0.95 kg/liter. This parameter change transforms the plastic from a low-density, high-volatility state to a high-density, low-volatility state, enabling increased recycling volume while maintaining coke strength
2Productivity
If small-sized plastic (5 mm or less) is used in large amounts, then the recycling efficiency increases, but the coke strength declines due to poor shape and low apparent density
Solution Approach 1:
The patent changes the apparent density parameter of small-sized plastic from below 0.40 kg/liter to 0.40-0.95 kg/liter through compression molding. This parameter transformation allows small plastic pieces to be used in large amounts for efficient recycling while the densified structure prevents coke strength decline
3Adaptability or versatility
If used plastic with high ash content is used, then the recycling scope expands to include lower quality waste, but the lump coke strength decreases
Solution Approach 1:
The patent applies preliminary compression molding to used plastic with high ash content before mixing with coal. This preliminary processing densifies the plastic and redistributes ash content, allowing broader recycling scope to include lower quality waste while maintaining lump coke strength through the densified matrix structure
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 enhances coke strength and quality while avoiding the need for expensive facilities to treat hydrogen chloride, allowing for efficient recycling of waste plastic without compromising coke production.
Implementation Method 1
Melting waste plastic between 160° C to 250° C
Implementation Method 2
dry distillation of plastic in a coke furnace
Data Source
AI summary
The present invention provides a method of reutilization and method of shaping of waste plastic which reduces the amount of volatile ingredients and oil cake* to extents preferable as materials for coke ovens, enables the formation of plastic granular materials able to maintain suitable shapes even after charging into a coke oven, and does not require expensive facilities for treating any produced hydrogen chloride gas, that is, a method of reutilization of waste plastic characterized by melting waste plastic at over 160° C. to 250° C. in temperature in part or whole, compression shaping it to thereby obtain a plastic granular material having an apparent density of 0.7 to 1.2 kg/liter, and mixing this plastic granular material with coal for dry distillation in a coke oven. By bringing the gas produced at the time of compression shaping the waste plastic into contact with water or an ammonia solution and combining the water or ammonia solution with an ammonia solution of an ammonia solution treatment facility attached to the coke furnace, it is possible to remove the hydrogen chloride contained in the produced gas.