Pipe Flow Shear Monitoring for Flocculant Injection Control
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Solution Overview
Problem
The effectiveness of flocculation chemicals in processing mature fine tailings from oil sands mining is hindered by high shear stresses, which break down flocs and disrupt the viscosity of the slurry, making it difficult to control the injection of chemicals effectively.
Innovation Solution
A method and apparatus that process signals from velocity profiles and pressure gradients in a pipe to determine the shear rate and shear stress, allowing for the regulation of chemical injection based on viscosity profiles, using SONAR-based velocity profiling and differential pressure measurements to balance shear rate and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high shear stress is applied to the slurry flow, then mixing and dispersion of chemicals is improved, but floc stability deteriorates and flocs are broken down
Solution Approach 1:
The system uses sonar-based velocity profile measurements and differential pressure sensors to continuously monitor shear rate and shear stress in the slurry flow. This feedback information is used to dynamically adjust chemical injection rates and pipeline flow conditions, optimizing dispersion while preventing excessive shear that would break down flocs.
Solution Approach 2:
The invention changes the operational parameters by measuring and controlling shear rate (through velocity profile analysis) and shear stress (through differential pressure measurements) to find the optimal operating window where chemical dispersion is effective but floc stability is maintained.
2Reliability
If chemical injection rate is increased to improve flocculation effectiveness, then settling performance is improved, but shear stress increases and destroys flocs
Solution Approach 1:
The system monitors shear stress through differential pressure measurements and uses this feedback to regulate chemical injection rates, ensuring that injection is optimized for flocculation effectiveness while preventing shear stress from reaching levels that would destroy flocs.
Solution Approach 2:
The invention implements dynamic control of chemical injection based on real-time measurements of flow conditions, adjusting injection rates according to actual shear stress and shear rate conditions rather than using fixed injection rates.
3Speed
If velocity gradient is increased to enhance chemical mixing, then dispersion speed is improved, but viscosity changes and floc stability is compromised
Solution Approach 1:
The system measures velocity profiles using sonar to determine shear rate and monitors its effect on viscosity. By tracking these parameter changes, the system can adjust operating conditions to maintain viscosity stability while achieving adequate dispersion speed.
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
Enables controlled and optimum injection of surfactants and flocculants, ensuring rapid dispersion without inducing prohibitively high shear stresses, thereby improving the settling process and maintaining floc stability.
Implementation Method 1
A SONAR-based velocity profile meter and a differential pressure meter arranged in relation to the pipe
Implementation Method 2
information about a plurality of velocity profiles of the flow in the pipe and about a pressure gradient of the flow over a length of the pipe
Data Source
AI summary
The present invention provides a new method and apparatus for receiving signals containing information about a plurality of velocity profiles of a flow in a pipe and about a pressure gradient of the flow over a length of the pipe; and determining information about an injection of a chemical into the flow in the pipe based at least partly on the information contained in the signals.