Gasification Unit Heat Management via External Pyrolysis Gas Oxidation
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Solution Overview
Problem
Existing gasification systems face challenges in efficiently producing cleaner product gas, particularly due to difficulties in heat supply for externally heated pyrolysis and sensitivity to dust and smaller particles in downstream configurations.
Innovation Solution
A gasification unit with a co-current or counterflow pyrolysis unit and gasifier, incorporating recycling and partial oxidation mechanisms, where pyrolysis gas is partially oxidized externally and used to heat the pyrolysis gas before re-entry, and product gas is used for heat exchange to control temperature and reduce tar content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If externally heated pyrolysis is used in larger scale, then heat supply becomes insufficient, but increasing heat supply complexity increases system complexity
Solution Approach 1:
The patent combines the pyrolysis unit and gasifier into an integrated system where the gasifier provides heat to the pyrolysis unit through a heat exchange means. This merging eliminates the need for separate external heating systems, providing sufficient heat supply while maintaining system simplicity.
Solution Approach 2:
The gasifier serves itself by using its own combustion process to generate heat that is transferred to the pyrolysis unit. The system is self-sufficient, with the gasifier's product gas used to heat the pyrolysis feed material, eliminating dependency on external heat sources.
2Productivity
If downstream configuration with coke bed is used, then gasification can proceed, but sensitivity to dust and smaller particles increases
Solution Approach 1:
The patent segments the gasification process into two distinct units: a pyrolysis unit for thermal decomposition and a gasifier for gas production. This segmentation allows each unit to be optimized independently, with the pyrolysis unit handling material preparation and the gasifier performing gasification, thereby reducing sensitivity to dust and particles.
3Object-generated harmful factors
If pyrolysis gas is partially oxidized inside the pyrolysis unit or gasifier, then tar decomposition improves, but temperature control becomes difficult
Solution Approach 1:
The patent extracts the partial oxidation process from the pyrolysis unit and gasifier by implementing an external heating device. This separate oxidation unit processes pyrolysis gas to produce heating gas, which is then used to heat the pyrolysis unit. This extraction allows independent optimization of tar decomposition and temperature control.
4Device complexity
If heating device is arranged internal to pyrolysis unit or gasifier, then space is saved, but control environment and tar decomposition quality decrease
Solution Approach 1:
The patent introduces an intermediary heating device that acts as a mediator between the pyrolysis unit and gasifier. This separate heating unit processes pyrolysis gas through partial oxidation and transfers the resulting heating gas to the pyrolysis unit via heat exchange means, providing controlled tar decomposition without compromising the main process units.
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 configuration provides a cost-efficient and controlled environment for producing cleaner product gas, improving heat management and tar decomposition, while reducing particle buildup and operational inefficiencies.
Implementation Method 1
heat exchange means arranged for heating at least a portion of the pyrolysis gas before it enters the pyrolysis unit through the pyrolysis gas inlet by means of at least a part of the product gas exiting the gasifier through the product gas outlet
Implementation Method 2
combustion unit arranged to least a partially oxidize the pyrolysis gas from the pyrolysis unit
Implementation Method 3
combustion unit in the heating device, wherein the combustion unit is arranged to least a partially oxidize the pyrolysis gas from the pyrolysis unit
Implementation Method 4
pyrolysis unit should be understood as any kind of unit capable of running a pyrolysis process, which is a thermochemical decomposition of organic material or fossil fuel at elevated temperatures in the absence of oxygen
Data Source
Figure 1
Figure 2
AI summary
Disclosed is a gasification unit (1) for producing a product gas. The gasification unit (1) comprises a co-current or counterflow pyrolysis unit (2) including a pyrolysis gas outlet (3) arranged at an upper part(4)of the pyrolysis unit (2) and a pyrolysis gas inlet (5) arranged at a lower part(6)of the pyrolysis unit (2). The gasification unit (1) further comprises a co-current or counterflow gasifier (7) including a product gas outlet (8) arranged at an upper part(9)of the gasifier (7) and a gasifier inlet (10) arranged at a lower part of the gasifier (7) and coke moving means (12) for allowing pyrolyzed coke (13) to move from the pyrolysis unit (2) to the gasifier (7). The gasification unit (1) also comprises recycling means (14) arranged to guide at least a part of the pyrolysis gas produced in the pyrolysis unit (2) from the pyrolysis gas outlet (3) and back to the pyrolysis gas inlet (5) and heating device (15) comprising an input conduit (16) arranged to guide pyrolysis gas from the pyrolysis gas outlet (3) to a combustion unit (17) in the heating device (15), wherein the combustion unit (17) is arranged to least a partially oxidize the pyrolysis gas from the pyrolysis unit (2), and wherein the heating device (15) comprises an output conduit (18) arranged to guide heating gas generated by the partial oxidization in the combustion unit (17) to the gasifier inlet (10), where in the heating device (15) is arranged external to the pyrolysis unit (2) and the gasifier (7)and wherein said gasification unit (1) further comprises heat exchange means (19) arranged for heating at least a portion of the pyrolysis gas before it enters the pyrolysis unit (2) through said pyrolysis gas inlet (5) by means of at least a part of the product gas exiting said gasifier (7) through said product gas outlet (8). Furthermore, a method for producing a product gas in a gasification unit (1) and use of such a method is disclosed.