Pneumatic Conveying Mass Flow Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Long pneumatic conveying lines in pulverized coal injection systems for blast furnaces experience significant fluctuations in mass flow rate, affecting the consistency of coal injection, despite existing control methods.
Innovation Solution
A dual-control system is implemented, comprising an upstream flow control system with a flow control valve and mass flow rate determination means, and a downstream flow control system with multiple flow control valves and sensors, allowing for precise adjustment of mass flow rates across the conveying line and distribution to injection lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a long pneumatic conveying line is used to transport pulverized coal from the upstream location to the downstream location, then the distance between the conveying hopper and the blast furnace can be increased, but significant fluctuations in mass flow rate occur
Solution Approach 1:
The conveying line is divided into multiple sections with intermediate hoppers positioned at specific intervals (e.g., every 500-1000 meters). Each section operates as a relatively independent conveying unit, which prevents the accumulation of flow fluctuations over long distances and maintains mass flow rate consistency across the entire system.
Solution Approach 2:
Intermediate hoppers are positioned in advance at strategic locations along the conveying line to proactively manage mass flow rate fluctuations. These hoppers act as buffer zones that regulate and stabilize the flow before it continues to the next section, preventing fluctuations from propagating through the entire system.
2Productivity
If mass flow rate control is implemented using existing methods (upstream control at conveying hopper or downstream control at distribution device), then the mass flow rate can be adjusted, but significant fluctuations persist over long conveying distances
Solution Approach 1:
The control system is segmented into multiple zones corresponding to the divided conveying sections. Each intermediate hopper is equipped with its own mass flow rate control mechanism, allowing localized adjustment and stabilization of flow rates in each section, which collectively maintains stability across the entire long-distance conveying system.
Solution Approach 2:
Mass flow rate sensors are installed at multiple locations including upstream of the conveying line, at intermediate hoppers, and downstream at the distribution device. These sensors provide real-time feedback to control systems that continuously adjust flow rates, enabling dynamic compensation for fluctuations and maintaining stable mass flow rate throughout the conveying process.
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 significantly reduces mass flow rate fluctuations, ensuring more consistent and precise coal injection, even over long distances, thereby improving the stability and efficiency of the blast furnace operation.
Implementation Method 1
a fluidizing device for fluidizing the pulverized coal at the outlet of the conveying hopper and forming a solid-gas flow
Implementation Method 2
a pneumatic conveying line for conveying said solid-gas flow from said fluidizing device to a downstream location
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An injection system for solid particles comprises a conveying hopper (11) located at an upstream location (1), a fluidizing device (21) for fluidizing the solid particles at the outlet of the conveying hopper (11) and forming a solid-gas flow, a pneumatic conveying line (15) for conveying the solid-gas flow from the fluidizing device (21) to a downstream location (2) and a static distribution device (17) with a plurality of injection lines (19), connected thereto. An upstream flow control system controls the mass flow rate in the pneumatic conveying line (15) at the upstream location (1) by controlling the opening of an upstream flow control valve (35) responsive to the solid material mass flow measured in the pneumatic conveying line (15) at the upstream location (1). A downstream flow control system controls the mass flow rate in the pneumatic conveying line (15) at the downstream location (2) by controlling the opening of a downstream flow control valve (51, 79i) responsive to the instantaneous mass flow rate sensed by a main downstream mass flow rate sensor (53).