Soot Removal in Waste Pyrolysis via Controlled Oxidation

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Solution Overview

Problem

The pyrolysis/gasification process generates soot that builds up in processing systems, degrading performance and posing a hazard due to potential flash combustion when the system is opened, especially in batch operations where extended cooling times are inefficient.

Innovation Solution

A method and system that switch from a standard pyrolysis/gasification mode to a secondary mode with increased oxygen levels to react soot with carbon monoxide, monitored by calorific value, hydrogen content, and temperature, allowing safe system opening even when parts are above combustion temperature, and a third mode for continued oxygen introduction to maintain soot removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the system is opened immediately after processing to change batches, then productivity is improved, but the soot may flash combust causing safety hazards

Engineering Contradiction:

Improvebatch change speedVSAvoidflash combustion hazard

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces oxygen into the hot processing chamber to deliberately combust the accumulated soot in a controlled manner, converting the harmful flash combustion hazard into a beneficial cleaning process. This oxidizes the soot deposits before batch change, eliminating the safety hazard while maintaining high productivity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-affected harmful factors

If the system is cooled down before opening to prevent soot combustion, then safety is improved, but processing time increases reducing productivity

Engineering Contradiction:

Improvesoot combustion preventionVSAvoidcooling time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

Instead of cooling the system to prevent soot combustion, the patent uses controlled oxidation with introduced oxygen to safely burn off the soot at high temperatures. This converts the previously harmful hot soot into a controlled cleaning process, eliminating the need for cooling time and maintaining high productivity

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the oxygen concentration parameter in the processing chamber from the pyrolysis/gasification mode to an oxidation mode by introducing additional oxygen. This parameter change enables controlled soot combustion at high temperatures, allowing safe operation without cooling

Inventive Principle:

Principle #35Parameter changes

3Productivity

If pyrolysis/gasification is performed to produce syngas, then useful product is generated, but soot buildup degrades system performance over time

Engineering Contradiction:

Improvesyngas productionVSAvoidsystem performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent implements periodic switching between pyrolysis/gasification mode and oxidation mode. During oxidation mode, oxygen is introduced to combust accumulated soot, cleaning the system surfaces and conduits. This periodic cleaning action prevents progressive soot buildup that would otherwise degrade heat transfer and system performance

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The oxidation process continuously removes soot deposits from system surfaces during dedicated cleaning cycles, maintaining heat transfer efficiency and preventing the gradual performance degradation that would occur without active soot removal

Inventive Principle:

Principle #20Continuity of useful action

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

Effectively prevents soot buildup, ensuring system safety and efficiency by safely allowing batch changes without waiting for temperature reduction, maintaining system performance and reducing operational hazards.

Implementation Method 1

heating the material in a processing chamber by recirculating hot gas therethrough, to pyrolyse and/or gasify it

Methodology Applied

Scientific EffectPyrolysis: Pyrolysis

Implementation Method 2

heating the material in a processing chamber by recirculating hot gas therethrough, to pyrolyse and/or gasify it

Methodology Applied

Scientific EffectGasification:

Implementation Method 3

increasing the oxygen content of the recirculating gas within the process such that the oxygen reacts with the heated soot to form carbon monoxide

Methodology Applied

Scientific EffectOxidation: Oxidation

Data Source

PatentUS9284504B2Waste processing

Publication Date: 2016.03.15 CHINOOK END STAGE RECYCLING

AI summary

This invention provides a system and method for pyrolyzing and/or gasifying material such as organically coated waste and organic materials including biomass, industrial waste, municipal solid waste and sludge. In a first mode of operation the method/system heats the material in a processing chamber (10) by passing hot gas therethrough. This pyrolyzes and/or gasifies the organic content it to produce syngas and, invariably, soot. In a second mode of operation the method/system increases the oxygen content of the hot gas such that the oxygen within the hot gas reacts with the heated soot to form carbon monoxide.