Hopper Cooling System for Dry Ash Extraction
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Solution Overview
Problem
Existing dry ash extraction systems face cooling inefficiencies due to reduced air flow as ash height increases, leading to malfunctions and wear in downstream components, especially when ash is stored at high temperatures and non-uniform profiles, and can be obstructed by slopes in conveyor systems, causing uneven cooling and obstruction of air passage.
Innovation Solution
The cooling system incorporates additional air intakes on the upper sidewalls of the hopper connected by a single pipe to the extractor, with a valve to maintain air flow during storage, and optional water nozzles for enhanced cooling, ensuring uniform air distribution and bypassing obstructions, using combustion chamber depression to draw in air and utilizing steam for additional cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is drawn through bottom valves during ash storage, then cooling of falling ash is achieved, but air flow is blocked when ash height exceeds valve level
Solution Approach 1:
The invention transitions from bottom-level air intakes (horizontal dimension) to upper sidewall air intakes (vertical dimension). Air enters through intakes positioned on the upper sidewalls of the hopper, flowing downward along the ash bed surface rather than attempting to penetrate through the ash column from below. This dimensional shift allows continuous air supply regardless of ash height.
Solution Approach 2:
The cooling system is segmented into multiple upper sidewall air intakes distributed around the hopper perimeter, connected via a common pipe to the extractor. This segmentation allows air to enter at multiple points along the upper hopper wall, ensuring uniform cooling air distribution across different storage conditions and ash profiles.
2Adaptability or versatility
If ash is stored in hopper for maintenance flexibility, then system adaptability improves, but cooling efficiency deteriorates due to increased ash height blocking air flow
Solution Approach 1:
By positioning air intakes on the upper sidewalls rather than at the bottom, the system maintains cooling capability during ash storage operations. The air flow path follows the ash bed surface downward, enabling continuous cooling regardless of whether the hopper is in storage or extraction mode, thus supporting system adaptability without sacrificing temperature control.
3Productivity
If conveyor slope exceeds natural declivity angle, then extraction efficiency improves, but ash accumulation obstructs air passage
Solution Approach 1:
The air intake system is repositioned to the upper sidewalls above the conveyor belt level. Air enters and flows downward along the ash bed surface, bypassing the obstruction created by ash accumulation in the conveyor curve section. This maintains air flow quantity even when the conveyor operates at slopes exceeding the natural declivity angle.
4Adaptability or versatility
If bottom valves are closed for storage, then maintenance capability improves, but non-uniform ash profile creates dead zones with poor cooling
Solution Approach 1:
Multiple air intakes are distributed around the upper sidewalls of the hopper, segmented to serve different zones. This segmentation ensures that cooling air reaches all areas of the ash bed, including non-uniform zones created during storage operations, eliminating dead zones and ensuring uniform temperature distribution throughout the hopper volume.
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 ensures consistent and uniform cooling of ash during storage and extraction, preventing malfunctions and wear by maintaining air flow even at maximum ash heights and slopes, and effectively managing ash temperature through controlled water addition, maintaining system efficiency and preventing ash humidification.
Implementation Method 1
the cooling of the ash on the extractor conveyor and on the subsequent conveyors is achieved by the thermal exchange by forced convection with air returning inside the system
Implementation Method 2
The position of the air intakes and nozzles is such that free entry of air is assured even in case of ash stored up to the maximum height expected. The resulting steam returns the furnace sucked up by the depression being therein and helps for a further cooling crossing the counter- flow falling ash.
Implementation Method 3
an uniform distribution of the cooling air over the hopper walls can be obtained... The position of the air intakes and nozzles is such that free entry of air is assured... The resulting steam returns the furnace sucked up by the depression being therein
Data Source
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AI summary
The present invention relates to a cooling system for dry extraction of heavy bottom ash output from furnaces for solid fuel during storing step at hopper, characterized by suitable air intakes (2), placed on the sidewalls of the hopper (1) at the hopper bottom, through which a controlled amount of cooling air passes sucked up in the combustion chamber (12) by the depression value therein, capable to achieve an uniform and balanced distribution system for such air during storing step at hopper (1) which optimizes the cooling of the falling ash, leaving the total amount of the air entering the furnace unchanged. The distribution header of the intakes (2) is connected to the extractor environment (6) by the lid (7) through a suitable conduit (3) provided with automated valve (8) being open during the storing step allowing the cooling air through to pass said intakes (2) placed on the sidewalls of the hopper (1). A more efficient cooling may be obtained by any addition of water input by nozzles (14) suitably placed within the hopper (1). The water amount may be adjusted such that the ash cooling improvement function is actuated without humidifying it.