Oxygen Enriched Pressurized Fluidized Bed Gasifier
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Solution Overview
Problem
Existing gasification technologies face challenges in efficiently processing high ash coal and biomass blends due to issues like heat loss, thermal imbalance, tar formation, and limited operational flexibility, which result in economic and environmental penalties.
Innovation Solution
The development of an oxygen enriched air blown pressurized fluidized bed pilot scale refractory lined gasifier capable of handling coal, biomass, washery rejects, and their blends in any proportion, with features such as preheating and thorough mixing of gaseous reactants, dual feeding arrangements, and advanced ash withdrawal systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If entrained flow gasifier is used for high ash coal, then gasification can be achieved, but enormous heat loss and thermal imbalance occur due to outgoing molten slag
Solution Approach 1:
The patent changes the operating parameters by operating at elevated pressures (3-10 atm) and temperatures (800-1050°C) in a pressurized fluidized bed, which fundamentally alters the gasification chemistry and heat transfer characteristics compared to atmospheric entrained flow, enabling efficient high ash coal gasification without excessive heat loss
Solution Approach 2:
The patent replaces the mechanical/physical quenching system of entrained flow with a chemical combustion system in the fluidized bed, where fuel combustion directly heats the bed material and generates syngas in-situ, eliminating the need for external quenching water and associated heat losses
2Productivity
If fixed bed gasification is used for high ash coal, then gasification can be achieved, but significant hazardous tar formation occurs requiring large capital investment for downstream processing
Solution Approach 1:
The patent operates at elevated temperatures (800-1050°C) and pressures (3-10 atm) in a fluidized bed, which fundamentally changes the gasification chemistry to favor syngas production over tar formation. The fluidized state provides superior heat and mass transfer, ensuring complete combustion and gasification even for high ash coals, thereby minimizing hazardous tar generation
Solution Approach 2:
The patent uses oxygen-enriched air (21-96% O2) instead of atmospheric air, providing a stronger oxidizing environment that promotes complete oxidation of carbon to CO and H2 rather than partial oxidation that forms tars. This accelerated oxidation dramatically reduces tar formation while improving gas quality
3Use of energy by moving object
If fluidized bed gasifier is used for high ash coal, then heat transfer between gas and solid phases improves, but agglomeration of ash particles may lead to defluidization and plant shutdown
Solution Approach 1:
The patent operates at elevated temperatures (800-1050°C) and controlled pressures (3-10 atm) that optimize the balance between heat transfer efficiency and ash particle behavior. These parameter changes enhance the fluidized state stability and reduce agglomeration tendencies, allowing continuous operation without defluidization
Solution Approach 2:
The use of oxygen-enriched air creates a more reactive combustion environment that reduces the residence time of ash particles in the bed, minimizing agglomeration opportunities. The enhanced oxidation also reduces the formation of fusible ash compounds that cause agglomeration, thereby maintaining reliable fluidized bed operation
4Productivity
If oxygen enriched air is used in fluidized bed gasifier, then gasification performance improves with high carbon conversion, but operational constraints and efficiency challenges arise
Solution Approach 1:
The patent implements a comprehensive parameter optimization system that adjusts pressure (3-10 atm), temperature (800-1050°C), oxygen concentration (21-96%), and feed rate dynamically to maximize carbon conversion while maintaining operational stability. This multi-parameter control enables high efficiency across different feedstock types and operating conditions
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 solution enhances gasification performance by achieving high carbon conversion, minimizing tar formation, and reducing downstream processing costs, while also allowing for flexible operation across a range of pressures, temperatures, and feedstock compositions.
Implementation Method 1
fluidized bed gasifier is capable to gasify wide range of feedstock... In a fluidized bed gasifier, the heat transfer between gas and solid phases is better owing to the fluid like behavior of the reactants
Implementation Method 2
combustion of some fraction of the feed to provide enthalpy to drive endothermic gasification of the reaming feed
Implementation Method 3
generate syngas for thermal and various downstream applications... gasification performance of coal, biomass, washery rejects and their blends
Data Source
AI summary
The present invention discloses oxygen enriched air blown pressurized fluidized bed pilot scale refractory lined gasifier of 1.5 TPD feed capacity to gasify coal, biomass, washery rejects, and their blends in any proportion in the actual atmosphere of commercial gasifier. The system is equipped in such a way that it can be operated in air/oxygen/oxygen enriched air/steam as well as their mixture in any proportion as per process requirement. The present invention discloses gasifier having feed rate carrying capacity up to 60 kg/hour, maximum operating temperature up to 1050° C. and pressure up to 10 kg/cm2. The facility consists different sections for gaseous and solid feeding, gasification, ash withdrawal, and gas Cooling & Cleaning. Besides gasification performance analysis, present invention is also discloses the study of agglomeration characteristics, entrainment and other fluidized bed gasification related parameters.