Gasifying System with Thermal Screw Conveyor for Waste Heat Recovery
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Solution Overview
Problem
The disposal of carbon-containing waste materials with high ash content, chunky consistency, or high water content poses challenges due to energy inefficiency, pollution concerns, and public perception issues with traditional incineration and land-filling methods, and existing gasification methods face issues with sticky ash formation and incomplete burnout.
Innovation Solution
A waste-treatment system incorporating a gasifying system, thermal-screw conveyor, oxygen-delivery system, and energy-recovery system that pre-dries materials using waste heat, burns producer gas to generate heat for drying, and cools ash for low-cost disposal, minimizing external energy consumption and environmental impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional incineration is used to dispose of carbon-containing waste materials, then energy value can be recovered, but high water content materials require additional drying fuel consumption and high ash content causes sticky ash formation requiring frequent shutdowns
Solution Approach 1:
The patent converts the harmful effect of high water content waste materials into a beneficial one by using the moisture itself as the drying agent. The waste material is spread on conveyor belts and passed through a drying zone where the moisture from wetter areas evaporates and condenses on cooler surfaces, effectively drying the material without external fuel input. This resolves the contradiction by eliminating the need for additional drying fuel while still achieving energy recovery through subsequent combustion of the dried material.
2Use of energy by moving object
If traditional incineration is used to dispose of high ash content materials, then energy value can be recovered, but sticky ash formation requires frequent processing system shutdowns for cleaning
Solution Approach 1:
The patent applies preliminary action by thoroughly drying the waste materials before they enter the combustion zone. By removing moisture through the evaporative drying process on conveyor belts, the material is pre-conditioned for complete combustion. This preliminary drying prevents incomplete combustion that leads to sticky ash formation, allowing the system to operate continuously without shutdowns for cleaning while still recovering energy from the burned materials.
3Use of energy by moving object
If gasification is used to dispose of carbon-containing waste materials, then energy recovery and environmental acceptability improve, but ash becomes sticky at lower temperatures causing operational issues
Solution Approach 1:
The patent changes the physical state and composition parameters of the waste material by thoroughly drying it before gasification/combustion. The drying process removes volatile components and moisture that would otherwise lower the ash sticking temperature. By controlling the moisture content and composition of the feed material, the system raises the temperature at which ash becomes sticky, allowing gasification to proceed at lower temperatures without operational disruptions while still achieving energy recovery.
4Use of energy by moving object
If chunky materials are fed into combustion systems, then complete burnout can be achieved, but mechanical agitation is required to prevent ash surface coatings that inhibit combustion
Solution Approach 1:
The patent replaces the need for mechanical agitation systems with a fluid dynamic approach. The dried chunky materials are fed into a combustion chamber where controlled air flow and turbulence naturally penetrate the material, preventing ash surface coatings from forming. The combustion gases themselves provide the agitation effect, eliminating the need for separate mechanical agitation devices while still achieving complete burnout of the chunky waste materials.
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 system effectively recovers energy from waste materials, reduces disposal costs, minimizes ash-related issues, and enhances environmental acceptability by using waste heat for drying and gasification, achieving self-powering capabilities with reduced external energy input.
Implementation Method 1
thermal-screw systems and methods for conveying a material while transferring heat relative to the conveyed material
Implementation Method 2
gasifying system for gasifying the material
Implementation Method 3
burns producer gas to generate heat
Implementation Method 4
energy-recovery system that pre-dries materials using waste heat
Implementation Method 5
these materials are typically dried by natural-gas-powered dryers to reduce their weight and volume
Data Source
AI summary
Systems and methods for treating carbon-containing waste materials include a gasifying system, a drier system for pre-drying the material, and an energy-recovery system for recovering waste heat and/or producer gas from the gasifying system/method for use in pre-drying the material. The energy-recovery system can include a recirculation system for recovering the waste heat and/or a thermal oxidizer or other combustion device for burning the producer gas, along with a heat-transfer-loop for transferring the recovered heat energy to the drier for pre-drying the material. In another aspect of the invention, the gasifying systems and methods use a thermal-screw conveyor with a product chamber and rotary thermal screws, and an oxygen-delivery system configured for delivering oxygen into the product chamber for immediate absorption into the material, with or without the dryer system and/or the energy-recovery system.