Flotation Control for Pulp Solids Removal
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Solution Overview
Problem
Existing flotation processes in paper pulp treatment struggle to maintain optimal operating conditions and quality when raw material composition and quality fluctuate, leading to suboptimal economic and technological performance.
Innovation Solution
Measuring the accept parameter at a consistency of 3-15% downstream of the flotation cell, with independent control of suspension and foam levels via valves and air quantity adjustment, allows for precise regulation of the flotation process to achieve high-quality stock and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the accept parameter is measured at the outlet of the flotation cell with low consistency (less than 1.5%), then the measurement can be performed close to the process, but the measurement accuracy is poor due to high air content and low stock consistency
Solution Approach 1:
The patent applies preliminary action by dewatering the accept stock before measurement to increase its consistency from less than 1.5% to more than 3%. This pre-treatment removes excess water and air, creating optimal measurement conditions and significantly improving measurement accuracy without unduly extending the control loop time
Solution Approach 2:
The patent introduces a dewatering device as an intermediary between the flotation cell outlet and the measurement point. This intermediary component processes the low-consistency accept stock, transforming it into a measurement-friendly state while maintaining the overall process efficiency
2Manufacturing precision
If the amount of flotation foam discharged is increased to improve accept purity, then the quality of the floated fiber material improves, but the yield of raw material decreases and fiber loss increases
Solution Approach 1:
The patent implements feedback control by continuously measuring accept parameters (such as brightness, ash content, or fiber quality) and using this information to automatically adjust the amount of flotation foam discharged. This closed-loop system enables the process to maintain optimal accept purity while minimizing fiber loss, as the foam discharge is dynamically optimized rather than operated at fixed extremes
Solution Approach 2:
The patent applies dynamics by making the foam discharge amount variable and responsive to real-time process conditions. Instead of a fixed discharge rate, the system dynamically adjusts foam removal based on measured accept quality, allowing optimal balance between purity and yield under varying operating conditions
3Manufacturing precision
If the suspension level in the flotation cell is regulated to maintain optimal separation, then the separation quality improves, but the system becomes less adaptable to changes in raw material composition and quality
Solution Approach 1:
The patent uses feedback control to continuously monitor accept parameters and automatically adjust suspension level and foam discharge to maintain optimal separation. This allows the system to adapt to changing raw material composition while preserving separation quality, as the control system compensates for variations in real-time
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting key process parameters (suspension level, foam discharge amount, air supply) based on measured accept quality. This enables the system to maintain optimal separation performance across varying raw material conditions by shifting operating parameters rather than relying on a fixed setpoint
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 approach enhances measurement accuracy and process control, enabling quick recovery to an economically and technologically optimal state by improving fiber material quality and yield while minimizing fiber loss and energy consumption.
Implementation Method 1
Flotation control Method for removing solids by means of gas bubbles from an aqueous fibrous suspension in a flotation plant
Implementation Method 2
the pulp remains in the fiber suspension due to its more hydrophilic character, while the impurities mentioned are hydrophobic and therefore get into the foam together with the air bubbles
Data Source
Figure 1~2
AI summary
The invention relates to a method for removing solids out of an aqueous fiber suspension (1) by means of gas bubbles in a flotation system comprising one or more flotation cells (2) in which flotation foam (4) is formed by feeding a fiber suspension/gas mixture (3). The flotation foam collects solids and is conducted out of the flotation cells (2) via an overflow (5) into at least one foam collection channel (6) and is accumulated there. The fiber suspension freed from the solids is discharged as accepted material (7) out of each flotation cell (2), and the height of the suspension surface in each flotation cell (2) and/or the height of the foam level of each flotation cell (2) can be changed dependent on at least one parameter of the accepted material (7) by means of a control system (8). The quality of the control process is to be improved by measuring the parameter of the accepted material (7) downstream of the flotation cell (2) at a material density of more than 3%.