Pyrolysis Gasifier Coupled with Chemical Looping Combustion
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Solution Overview
Problem
Current methods for treating organic solid waste, such as incineration and pyrolysis gasification, face challenges with high initial investment, operating costs, and difficulty in removing pollutants like SOx, NOx, and tar, while chemical looping combustion struggles with ash-induced sintering and corrosion, necessitating a more efficient and cost-effective solution.
Innovation Solution
A method and apparatus combining pyrolysis with chemical looping combustion, utilizing a system with an air reactor, fuel reactor, and pyrolysis gasifier, where pyrolysis gas undergoes chemical looping combustion with a metal oxide oxygen carrier, effectively removing tar and N/S/Cl pollutants, and utilizing waste heat for self-heating, reducing pollutant emissions and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If incineration is used to treat organic solid waste, then treatment speed and volume reduction rate are improved, but pollutant emissions (SOx, NOx, dioxins) and operating costs increase
Solution Approach 1:
The system segments the treatment process into two distinct reactors: a fuel reactor for pollutant-free combustion and an air reactor for oxygen carrier regeneration. This segmentation allows the fuel reactor to operate without forming SOx and NOx, while the air reactor handles the oxidation reactions separately, thus resolving the contradiction between fast treatment and low emissions.
Solution Approach 2:
The oxygen carrier (metal oxide) serves as an intermediary substance that transfers oxygen from the air reactor to the fuel reactor. This intermediary enables complete combustion and high treatment speed in the fuel reactor without direct contact with atmospheric oxygen, preventing the formation of harmful pollutants like SOx and NOx.
2Object-generated harmful factors
If chemical looping combustion is used, then pollutant removal is improved, but oxygen carrier lifespan decreases due to ash-induced sintering and corrosion
Solution Approach 1:
The system extracts the oxygen carrier regeneration process into a separate air reactor, isolating it from the organic solid waste and its ash in the fuel reactor. This extraction prevents direct contact between the oxygen carrier and harmful ash components, reducing sintering and corrosion while maintaining effective pollutant removal through controlled oxidation in the air reactor.
3Object-generated harmful factors
If pyrolysis gasification is used, then pollutant emissions are reduced, but tar and N/S/Cl pollutants remain in the gas stream
Solution Approach 1:
The system performs preliminary pyrolysis gasification in the fuel reactor to convert organic solid waste into combustible gases, then immediately follows with chemical looping combustion of the produced gas. This preliminary action sequence ensures that tar and N/S/Cl pollutants formed during pyrolysis are subsequently removed by oxidation in the same reactor, achieving complete pollutant removal.
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 approach reduces pollutant emissions, extends oxygen carrier lifespan, lowers initial investment and operating costs, and enables efficient, harmless disposal of organic solid waste with resource utilization, making it a more viable and clean treatment method.
Implementation Method 1
the lattice oxygen in the oxygen carrier of metal oxide (MeO) is used in a looping reaction to completely oxidize the fuel to CO2 and H2O in a fuel reactor
Implementation Method 2
organic substances in the solid waste are converted into combustible gases containing H2, CH4, CO, CnHm, tar and ash via a series of thermochemical reactions under certain temperature and pressure conditions and in the absence of oxygen or oxygen-deficient environment
Implementation Method 3
the reduced oxygen carrier (Me) after the reaction is re-oxidized by air in an air reactor to restore the lattice oxygen for recycling
Implementation Method 4
utilizing waste heat for self-heating, reducing pollutant emissions and operational costs
Data Source
AI summary
A method and apparatus for removing pollutants from organic solid waste by pyrolysis coupled with chemical looping combustion are provided. The apparatus includes: an air reactor, a fuel reactor, and a pyrolysis gasifier. The pyrolysis gasifier is sleeved outside the fuel reactor, and the air reactor is connected with the fuel reactor. A top end of the air reactor is connected with a top delivery pipe; the top delivery pipe is connected with a first cyclone separator; and the first cyclone separator is connected with an oxygen carrier refeeder provided at a top end of the fuel reactor. The apparatus forms a two-stage reaction unit of pyrolysis and chemical looping combustion by decoupling the pyrolysis process from the chemical looping combustion, which avoids the contact between the complex ash of organic solid waste and the oxygen carrier, thereby improving the service life of the oxygen carrier.