Multi-Vessel Ash Transport Pressure Control
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Solution Overview
Problem
Existing ash transport systems for coal combustion waste products face inefficiencies due to low capacity, high energy consumption, ash clumping, pipe erosion, and poor discharge efficiency from pyramid-shaped hoppers, leading to suboptimal operation and reduced conveyance rates.
Innovation Solution
An ash transport system with pressure sensors and programmable airlock sequencing logic that adjusts the discharge of ash from multiple hoppers based on pressure thresholds, ensuring continuous and efficient ash flow into the transport line, thereby maintaining optimal pressure and reducing pipe erosion and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If single airlock dumping is used to maintain pressure control, then pressure stability is improved, but transport capacity and productivity deteriorate
Solution Approach 1:
The system divides the airlock discharge function into multiple independent airlocks (first airlock, second airlock, etc.) that can operate simultaneously or sequentially. Each airlock has its own outlet valve controlled by independent pressure thresholds, allowing the system to segment the discharge process while maintaining overall pressure control through coordinated operation of multiple units.
Solution Approach 2:
The system uses multiple airlocks to provide excess discharge capacity beyond what a single airlock could deliver. By having redundant airlock units that can activate based on pressure conditions, the system ensures that transport capacity requirements are met while pressure stability is maintained through selective activation of appropriate airlocks.
2Speed
If high pickup velocity is used in dilute phase transport, then transport velocity is improved, but pipe erosion worsens
Solution Approach 1:
The system dynamically adjusts transport parameters by using multiple airlocks that can be activated based on real-time pressure conditions. This dynamic control allows the system to optimize between transport velocity and pipe erosion by coordinating the discharge timing and rate of multiple airlocks, thereby regulating the overall solids flow rate into the transport line.
3Volume of stationary object
If pyramid-shaped hoppers are used to maximize space, then storage volume is improved, but discharge efficiency worsens
Solution Approach 1:
The system segments the discharge function across multiple airlocks positioned at different locations (e.g., front row and back row hoppers). This segmentation allows material to be drawn from different hopper zones simultaneously, overcoming the discharge inefficiencies inherent in pyramid-shaped hoppers while maintaining high storage volume utilization.
Solution Approach 2:
The airlocks serve as intermediary devices between the pyramid-shaped hoppers and the transport line. These intermediaries facilitate efficient discharge by providing a controlled interface that overcomes the friction and flow resistance problems in pyramid hoppers, allowing material to be fed into the airlock and then transported efficiently to the line.
4Productivity
If multiple airlocks are emptied simultaneously, then transport capacity is improved, but pressure control becomes difficult
Solution Approach 1:
The system employs dynamic pressure-based control where each airlock's outlet valve is activated based on real-time pressure threshold comparisons. This dynamic control mechanism allows multiple airlocks to operate simultaneously when pressure conditions permit, maximizing transport capacity while automatically maintaining pressure control through the pressure-sensitive activation logic.
Solution Approach 2:
The system changes operational parameters (which airlocks are active) based on pressure conditions. By monitoring pressure and selectively activating airlocks based on pressure thresholds, the system adjusts the number and combination of active airlocks to match transport demands while maintaining pressure stability, thereby resolving the contradiction between capacity and control.
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 enhances ash transport capacity by maintaining stable pressure and reducing pipe erosion and energy consumption, improving the overall efficiency and reliability of ash transport by ensuring continuous and efficient ash flow.
Implementation Method 1
a pressure sensor for measuring pressure in the transport line
Implementation Method 2
In pressure type pneumatic conveying systems, pressurized air transports fly ash
Implementation Method 3
In dilute phase transport, the pickup velocity, which is the air velocity based on total pipe area, is typically above 3,500 feet per minute. Thus the solids are mostly suspended during conveyance.
Implementation Method 4
By comparison, in dense phase transport, the pickup velocity is nominally below 2,000 feet per minute, which yields high solid transport rate but with the solid being only partially suspended.
Implementation Method 5
In a vacuum system, a vacuum pump sucks transport air and fly ash from the hoppers and then through transport piping
Implementation Method 6
An electrostatic precipitator or a bag house system typically collects the fly ash
Implementation Method 7
An electrostatic precipitator or a bag house system typically collects the fly ash
Data Source
AI summary
An ash transport system and method is provided that includes a transport line, four hoppers, and an airlock or hopper valve attached to each hopper. The ash transport system transports an ash mass from the airlock or hopper valve to the transport line if pressure in the transport line falls below a predefined pressure threshold assigned to the respective airlock or hopper valve. After a predefined period of time elapses, the ash transport system transports the ash mass from the airlock or hopper valve to the transport line if the pressure in the transport line falls below different respective predefined pressure thresholds. The airlocks and hopper valves simultaneously transport the ash masses to the transport line if, prior to the predefined period of time elapsing, the pressure in the transport line falls below each of the respective predefined pressure thresholds.