Pneumatic Coal Injection Hopper Depressurization Control
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Solution Overview
Problem
Existing pneumatic transport and injection systems for granular or powder materials, such as coal, face issues with precise control during depressurization of dispensing hoppers, leading to inefficiencies and equipment costs, as well as interference with weighing systems and inaccurate measurement of coal quantity due to shared bag filters and large diameter ducts.
Innovation Solution
The system incorporates a pressurized bag filter mounted directly on each dispensing hopper, with flow control means located downstream of the filter to manage the depressurization process, eliminating the need for large diameter ducts and allowing for precise control of the coal quantity measurement by using a de Laval nozzle or plate with a predetermined orifice to maintain a constant volumetric flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a shared bag filter is used for multiple dispensing hoppers, then equipment costs are reduced, but measurement precision of coal quantity is degraded due to interference with weighing systems
Solution Approach 1:
The patent divides the shared bag filter system into individual dedicated bag filters for each dispensing hopper. This segmentation eliminates interference with weighing systems and enables precise measurement of coal quantity for each hopper independently, while still maintaining cost-effectiveness through standardized filter design.
2Productivity
If large diameter ducts are used for depressurization, then flow rate is improved, but device complexity and equipment costs increase
Solution Approach 1:
The patent changes the operational parameters of the bag filter by operating it under pressure differential conditions during depressurization. This allows the use of smaller diameter ducts while maintaining adequate flow rates, thereby reducing device complexity and equipment costs without sacrificing productivity.
3Manufacturing precision
If flow control means are placed upstream of the bag filter, then control precision is improved, but the risk of clogging increases
Solution Approach 1:
The patent inverts the conventional arrangement by placing the flow control means (orifice plate or de Laval nozzle) downstream of the bag filter rather than upstream. This inversion ensures that the flow control element operates with clean filtered gas, eliminating the risk of clogging from powder material while maintaining precise flow rate control through the depressurization process.
4Productivity
If pressure-equalizing ducts are used during filling, then filling efficiency is improved, but the risk of condensation and clogging increases
Solution Approach 1:
The patent extracts and eliminates the pressure-equalizing duct system from the filling process. Instead of using separate pressure-equalizing ducts that are prone to condensation and clogging, the system relies on the main depressurization duct with bag filter to manage pressure equalization, thereby removing the source of condensation and clogging problems while maintaining filling 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
This configuration reduces equipment costs, prevents clogging, and ensures accurate measurement of coal injected into tuyeres by eliminating the need for pressure-equalizing ducts and shared bag filters, allowing for efficient and precise control of the coal flow during depressurization.
Implementation Method 1
using a de Laval nozzle or plate with a predetermined orifice to maintain a constant volumetric flow rate
Implementation Method 2
a bag filter, having a maximum operating flow rate, connected to the depressurizing duct
Data Source
AI summary
An installation for distribution of granular or powder material via pneumatic transport comprising at least one dispensing hopper (3) for temporary storage of said granular or powder material, the dispensing hopper being suited to being, alternately, pressurized for emptying the dispensing hopper and depressurized to permit filling thereof, and a device for depressurizing said dispensing hopper. The depressurizing device comprises a depressurizing duct (12) connected to said dispensing hopper, a bag filter (11), having a maximum operating flow rate, connected to the depressurizing duct, and flow control means (15) for controlling the flow rate in said depressurizing duct through the bag filter. The bag filter (11) is suited to operating under pressure, and the flow control means (15) are located on the depressurizing duct (12) downstream of the bag filter (11) and are arranged to provide a flow rate which is at most equal to the maximum flow rate of the bag filter. Application in particular to an installation for injecting coal into a blast furnace.