Solids Deaeration Zone for Coal Gasification
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Solution Overview
Problem
Current dry coal gasification systems face inefficiencies in conveying fine particulate materials due to shear failure and flow stagnation zones, particularly with dry coal extrusion pumps, which hinder mechanical efficiency and lead to clogging issues.
Innovation Solution
A solids supply system comprising a solids deaeration zone with sloped walls that compact particulate materials before entry into a solids pump zone, allowing effective conveyance through the pump by forming stress-transmitting bridges, thereby eliminating shear failure and flow stagnation zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If dry coal extrusion pumps are used to convey fine particulate materials, then the pumping capability is provided, but shear failure zones and flow stagnation zones occur leading to decreased mechanical efficiency
Solution Approach 1:
The deaeration zone is positioned upstream of the pump inlet to pre-compaction and deaerate the particulate material before it enters the pumping mechanism. This preliminary action ensures the material is in optimal condition for efficient pumping, preventing shear failure and flow stagnation zones within the pump itself.
Solution Approach 2:
The deaeration zone acts as an intermediary component between the material source and the pump inlet. It serves as a buffer zone where material conditioning occurs, eliminating the need for the pump to handle aerated or poorly compacted material that would cause efficiency losses.
2Productivity
If external force is applied to compress powdery material to form stress-transmitting bridges, then conveyance effectiveness improves, but the material overly consolidates and clogs the inlet or transport channel
Solution Approach 1:
The deaeration zone provides a localized environment with controlled compaction conditions. The gradual compression and extended residence time allow uniform stress distribution throughout the material bed, creating stress-transmitting bridges without localized over-consolidation that would lead to clogging.
Solution Approach 2:
The deaeration zone changes the physical parameters of the particulate material by controlling pressure, residence time, and gas removal. These parameter changes optimize the material's flow properties and compaction characteristics, enabling effective bridge formation without excessive consolidation.
3Use of energy by moving object
If cycling lock hopper is used to pump dry coal to high pressure, then thermal cold gas efficiency is improved, but mechanical efficiency is relatively low and capital costs are high
Solution Approach 1:
The invention extracts and eliminates the complex high-pressure valve and compressor system from the traditional cycling lock hopper design. By using a simpler deaeration zone combined with a basic solids pump, the system achieves comparable or superior thermal efficiency without the mechanical complexity and associated costs.
Solution Approach 2:
The complex mechanical high-pressure generation system (valves and compressors) is replaced with a simpler system combining a deaeration zone and a basic solids pump. This substitution reduces mechanical complexity while maintaining or improving overall system efficiency.
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 system achieves high mechanical efficiency, approaching 80%, and can pump pulverized dry coal to pressures over 1200 psi, effectively conveying fine particulates without clogging, enhancing the overall efficiency and reliability of the gasification process.
Implementation Method 1
a passageway defined by one or more sloped walls... converging in a longitudinal direction from an inlet toward an outlet, forming a wall angle to a vertical plane... to become sufficiently compacted to be effectively conveyed
Implementation Method 2
The aerated fine particulate and powdery material may not be compacted enough to form a stress transmitting bridge of contacting particles... to cause the particles to transmit stresses across their contacts
Data Source
AI summary
A solids supply system having a solids deaeration zone and a solids pump zone, and a method for supplying the solids e.g., pulverized dry coal, to an application, e.g., gasification process. The solids deaeration zone includes a container having a passageway defined by one or more sloped walls. The solids deaeration zone is operable to deaerate and convey the solids to the solids pump zone. In the solids deaeration zone, the solids become sufficiently compacted prior to and upon entry into the solids pump zone to be effectively conveyed through the solids pump zone.