Stepped Constrained Wind Air Distributor for Gasifier Ash Leakage
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Solution Overview
Problem
Existing gasifiers face challenges such as low thermal efficiency, tar contamination, and ash leakage due to inadequate temperature control and deslagging in circulating fluidized bed gasifiers, and combined gasifiers struggle with maintaining gasification temperature and ash retention.
Innovation Solution
An internally self-circulating fluidized bed gasifier with an air distributor that generates a stepped constrained wind, featuring winding vent holes and a converging outlet design, which creates a non-uniform gas flow to prevent ash leakage and ensure consistent gasification temperature, allowing for repeated self-circulation and high efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circulating fluidized bed gasifier is used, then clean coal gas is produced without tar contaminants, but thermal efficiency is low and semi-coke accumulates in the coal slag
Solution Approach 1:
The gasifier is divided into distinct functional zones: a combustion chamber for high-temperature burning and a gasification chamber for tar-free gas production. This segmentation allows each zone to optimize for its specific function, achieving both high thermal efficiency in combustion and clean gas output in gasification.
Solution Approach 2:
The invention introduces a vertical dimension to the gasifier design with the combustion chamber positioned below the gasification chamber. This spatial arrangement enables gravitational circulation of materials and heat transfer from the lower combustion zone to the upper gasification zone, simultaneously achieving high thermal efficiency and clean gas production.
2Productivity
If a combined gasifier is designed, then burning efficiency is substantially increased and tar-free gas is produced, but gasification temperature cannot be ensured and non-coal substances accumulate at the bottom
Solution Approach 1:
A self-circulation system is implemented where combustion products and heat from the combustion chamber automatically circulate back to the gasification chamber. This feedback mechanism ensures continuous high-temperature gasification conditions are maintained, preventing temperature drops and accumulation of non-coal substances.
Solution Approach 2:
The gasifier utilizes its own combustion heat and gas flow to drive the gasification process in the upper chamber. The system is self-sustaining, with the combustion chamber providing both thermal energy and fluid circulation to maintain gasification temperature without external intervention.
3Ease of operation
If wind holes are arranged in the air distributor, then gas distribution is improved, but solid-phase materials may leak into the gas mixture chamber
Solution Approach 1:
The air distributor is designed with a stepped structure that creates constrained wind flow patterns before gases enter the gas mixture chamber. This preliminary flow conditioning prevents solid particles from following the gas stream into the chamber below, eliminating ash leakage while maintaining effective gas distribution.
Solution Approach 2:
Different regions of the air distributor have different structural characteristics: the stepped structure creates high-velocity constrained wind in the center for good gas distribution, while the periphery structure prevents particle escape. This local differentiation of structural quality achieves both objectives simultaneously.
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
The solution achieves self-circulation combustion gasification multiple times, maintains well-controlled gasification temperature, prevents ash leakage, and enhances coal gasification efficiency while ensuring effective material circulation and temperature management within the furnace chamber.
Implementation Method 1
The vent holes are designed to have winding paths. The stepped constrained wind has a higher flow rate in the middle and a lower flow rate in the periphery
Implementation Method 2
an internally circulating flow is formed within the furnace chamber in which a middle constrained gas moves upwardly and a periphery gas stream overflows downwardly
Implementation Method 3
the air distributor enables a gas entering the gasifier to form a stepped constrained wind and effectively prevents solid-phase materials in a furnace chamber from leaking into a gas mixture chamber
Data Source
Figure 1
AI summary
The present invention provides an internally self-circulating fluidized bed gasifier and an air distributor (2) therein for generating a stepped constrained wind. The air distributor (2) for generating a stepped constrained wind includes an air distributor body (200), a gas-material mixture through hole (203) and a plurality of vent holes (201) located within the air distributor body (200). The gas-material mixture through hole (203) extends from a top surface of the air distributor body (200) into the air distributor body (200). Outlets of the plurality of vent holes (201) are in communication with the bottom of the gas-material mixture through hole (203). Inlets of the plurality of vent holes (201) are located at a bottom surface of the air distributor body (200). The vent holes (201) are designed to have winding paths. Compared to the prior art, by providing the arrangement of the winding paths of the vent holes (201) of the air distributor (2) and converging the outlets of the vent holes (201) to the same large hole channel, i.e. the gas-material mixture through hole 203, the present invention enables a gas entering the gasifier to form a stepped constrained wind and effectively prevents solid-phase materials in a furnace chamber (1) from leaking into a gas mixture chamber (3). The internally self-circulating fluidized bed gasifier of the present invention can achieve self-circulation combustion gasification multiple times within the gasifier and has advantages such as well control of gasification temperature within the gasifier, a high coal gasification efficiency and no ash leakage.