High Pressure Coal Feeder Micro-Fluidization Lock Vessel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for feeding granular or fine coal with high moisture content to high-pressure gasifiers face challenges such as high drying costs, coal packing issues in lock vessels, and difficulties in maintaining accurate metering due to varying coal properties and moisture levels, leading to inefficiencies and operational interruptions.
Innovation Solution
A solids feed system that employs micro-fluidization and pressure control methods to ensure coal particles dislodge from the lock vessel into the feed vessel, using gas venting elements and pressure control devices to maintain a constant pressure difference and control coal feed rate, even with high moisture content coals, thereby preventing packing and ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slurry coal feed system is used to feed high moisture coal, then the coal can be pumped into high pressure gasifier, but the drying cost increases significantly and thermal efficiency decreases due to double evaporation of moisture
Solution Approach 1:
The invention changes the moisture content parameter of the coal feed from high (30-45%) to low (<10%) by implementing a drying system. This parameter change allows the coal to be fed directly without slurry preparation, eliminating the need for double evaporation and improving thermal efficiency while maintaining reliable coal feed to the gasifier
Solution Approach 2:
The invention extracts the moisture from the coal through a drying system before feeding to the gasifier. By removing the harmful excess moisture content, the system avoids the energy penalty of evaporating water twice (once during drying and again in the gasifier), thereby improving thermal efficiency while ensuring reliable feed
2Stress or pressure
If lock vessel with rotating metering device is used to feed granular coal, then pressure can be increased from atmospheric to operating pressure, but coal packing occurs in the lock vessel when moisture exceeds 5%, causing feed interruption
Solution Approach 1:
The invention changes the moisture content parameter of the coal to below 10% through a drying system. This parameter change prevents coal particles from sticking together and packing in the lock vessel during pressurization, ensuring continuous reliable feed operation without interruptions
Solution Approach 2:
The invention performs preliminary drying of the coal before it enters the lock vessel and feeding system. By removing excess moisture in advance, the system prevents the harmful packing effect from occurring during subsequent pressurization and feeding operations, ensuring continuous reliable operation
3Measurement precision
If rotating metering device is used to meter coal feed rate, then accurate metering can be achieved, but the device fails when coal moisture increases due to packing and bridging
Solution Approach 1:
The invention changes the moisture content parameter of the coal to below 10% through drying. This parameter change ensures that the rotating metering device operates reliably without experiencing packing and bridging, maintaining both metering accuracy and continuous operation
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 effectively maintains a consistent coal feed rate to the gasifier, reducing operational interruptions and maintaining process efficiency by fluidizing coal particles and controlling pressure differences, even with coals having high moisture content up to 25%, thus enhancing the reliability and economic viability of gasification processes.
Implementation Method 1
micro-fluidization and pressure control methods to ensure coal particles dislodge from the lock vessel into the feed vessel, using gas venting elements
Implementation Method 2
pressure control devices to maintain a constant pressure difference and control coal feed rate
Data Source
AI summary
A coal feed system to feed pulverized low rank coals containing up to 25 wt % moisture to gasifiers operating up to 1000 psig pressure is described. The system includes gas distributor and collector gas permeable pipes imbedded in the lock vessel. Different methods of operation of the feed system are disclosed to minimize feed problems associated with bridging and packing of the pulverized coal. The method of maintaining the feed system and feeder device exit pressures using gas addition or extraction with the pressure control device is also described.