In-Line Chemical Blending Control for Variable Output Flow
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Solution Overview
Problem
Continuous in-line blending systems face challenges in maintaining accurate flow ratios and stability when output rates change, leading to loss of blend accuracy and increased waste due to overshoot, undershoot, and oscillations, especially when starting and stopping processes, which requires the use of surge tanks and results in complex systems with substantial volume and waste.
Innovation Solution
An on-demand blending system that uses real-time metrology and proportional flow control to maintain a desired concentration range by dynamically adjusting flow rates, allowing for precise blend accuracy and minimizing waste by eliminating the need for fixed storage volumes and reducing system complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous in-line blending systems dynamically adjust flow rates to meet changing demand, then productivity and flexibility are improved, but blend accuracy deteriorates due to loss of ratio control, overshoot, undershoot, and oscillations
Solution Approach 1:
The patent implements feedback control by continuously monitoring the actual flow rates of constituent fluids and the blended output, then adjusting control valve positions to maintain desired blend ratios. The system measures actual flow conditions and uses this information to correct deviations, ensuring blend accuracy is maintained even when demand changes dynamically.
Solution Approach 2:
The patent employs dynamic control strategies that adapt to changing flow conditions in real-time. The control system continuously adjusts valve positions and flow rates based on current demand requirements, transitioning smoothly between different operating points while maintaining blend accuracy through active control rather than fixed static settings.
2Reliability
If surge tanks are added to maintain stability during start-up and stoppage, then reliability is improved, but device complexity and system volume increase
Solution Approach 1:
The patent prepares the blending system for stable operation by pre-establishing proper flow ratios and controlling the sequence of fluid introduction before blending begins. The system proactively manages start-up conditions by controlling the timing and rate of fluid introduction, preventing instability before it occurs rather than requiring surge tanks to correct it later.
Solution Approach 2:
The patent removes the need for surge tanks by extracting their stabilizing function and implementing it directly within the continuous blending process through controlled flow management. The system achieves stability without the intermediate storage vessels by maintaining continuous flow and using control algorithms to prevent the conditions that would require surge tanks.
3Manufacturing precision
If large batch volumes are used to overcome measurement imprecision, then manufacturing precision is improved, but loss of substance increases due to waste from open tanks and cleaning effluents
Solution Approach 1:
The patent implements continuous blending where constituent fluids are mixed and delivered on-demand without interruption. This eliminates the batch cycle of filling, mixing, holding, and cleaning open tanks, maintaining continuous useful action throughout the process. The system blends chemicals continuously in closed conduits, preventing exposure to atmosphere and eliminating waste associated with batch operations.
Solution Approach 2:
The patent converts the potential harm of measurement imprecision in small volumes into a benefit by using continuous flow measurement and control. Rather than needing large volumes to mask measurement errors, the system uses precise flow meters and control algorithms that accurately measure and adjust small flow rates in real-time, turning the challenge of small-volume measurement into an opportunity for precision and waste reduction.
4Device complexity
If fixed-rate continuous blending is used to simplify the process, then device complexity is reduced, but adaptability deteriorates when demand rates change
Solution Approach 1:
The patent employs dynamic control strategies that adapt to changing flow conditions in real-time. The control system continuously adjusts valve positions and flow rates based on current demand requirements, transitioning smoothly between different operating points while maintaining blend accuracy through active control rather than fixed static settings.
Solution Approach 2:
The patent changes operating parameters such as flow rates and valve positions in response to varying demand conditions. The system maintains simplicity by adjusting parameters through automated control rather than complex mechanical reconfiguration, allowing flexible adaptation to different demand rates while keeping the overall system design straightforward.
Data Source
AI summary
This in-line active and reverse calculating mass balance blending system can maintain a chemical at desired control points, such as with respect to concentration, temperature, and/or pressure, while the output flow rate is changing dynamically to a point of use. A blending unit is configured to receive and blend at least two species and deliver a mixture at selected concentrations to points of use. A controller can be configured to determine a mass balance to maintain the concentrations in the mixture using information from metrology systems and a flow in an output to the at least one point of use. The controller also can be configured to maintain a concentration in the mixture within a concentration range by controlling flow rates to the blending unit.