Waste Gasification and Plasma Cleanup for Low-Tar Syngas
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Solution Overview
Problem
Current waste treatment methods, such as gasification, produce uncombusted particulates and hazardous tar species, leading to environmental concerns and increased maintenance costs due to clogging issues in turbines when using the resulting gas.
Innovation Solution
A process combining gasification and plasma treatment of waste, followed by plasma treatment of the offgas and char, in the presence of oxygen and steam, to reduce particulates and hazardous materials, resulting in a cleaner syngas with lower tar and heavy metal content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gasification is used to process waste, then waste volume is reduced and energy is recovered, but uncombusted particulates and hazardous tar species are produced
Solution Approach 1:
The patent changes the operating parameters of the gasification process, specifically using a two-stage gasification approach with controlled oxygen supply in each stage. The first stage operates at lower temperature with limited oxygen to produce syngas, while the second stage operates at higher temperature to combust remaining particulates and tar species, thereby reducing harmful emissions while maintaining processing efficiency
Solution Approach 2:
The patent introduces excess oxygen in the second gasification stage to accelerate the combustion of uncombusted particulates and hazardous tar species. This strong oxidation approach converts harmful components into less harmful combustion products (CO2 and H2O), resolving the contradiction between waste processing efficiency and harmful emissions
2Use of energy by moving object
If gasification produces combustible gas for turbines, then energy recovery is improved, but turbine maintenance costs increase due to clogging from particulates and tarry species
Solution Approach 1:
The patent performs preliminary combustion of particulates and tar species in the second gasification stage before the gas reaches the turbine. By pre-treating the combustible gas to remove harmful components through controlled combustion, the gas is cleaned in advance, preventing turbine clogging and reducing maintenance requirements while preserving energy recovery capabilities
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 combination significantly reduces airborne particulates and tar compounds, converting char to gas with low particulate content, and degrades harmful species, producing a cleaner fuel gas suitable for turbines with reduced maintenance needs.
Implementation Method 1
a plasma treatment step comprising subjecting the offgas and the char product to a plasma treatment in a plasma treatment unit
Implementation Method 2
a gasification step comprising treating the waste in a gasification unit to produce an offgas and a char
Data Source
AI summary
A process for the treatment of waste, the process comprising either a gasification step or a pyrolysis step to produce an offgas and a non-airborne, solid char material; followed by a a plasma treatment step. An associated apparatus having a plasma treatment unit which is separate from the gasification unit or pyrolysis unit.