NIR Spectroscopy for PolyAluminium Chloride Process Control
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Solution Overview
Problem
Current processes for producing polyaluminium chloride hydroxide (PAC) face inaccuracies in controlling product concentrations and composition, leading to high deviations and instability, which complicates process control and increases costs due to the need for offline analysis and extensive personnel and equipment requirements.
Innovation Solution
Implementing near-infrared analysis (NIR) for continuous online monitoring of Cl and Al ion concentrations during the hydrometallurgical processing of aluminum-containing compounds, allowing for real-time adjustments through a mathematical control model to maintain precise control over the production process, ensuring accurate and stable production of PAC within the desired basicity range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline analysis techniques such as titrations are used to monitor process media and process progress, then product quality can be verified, but the analysis is time-consuming and the process can only be influenced after a considerable period
Solution Approach 1:
The patent replaces offline mechanical/chemical analysis methods (titrations) with online near-infrared spectroscopy (NIR) analysis. The NIR system continuously monitors process media composition and process progress in real-time, eliminating the time-consuming nature of offline titrations while maintaining measurement precision for product quality verification.
Solution Approach 2:
The patent introduces an intermediate measurement system (NIR spectroscopy) that acts as a bridge between the chemical process and control decisions. This intermediary provides real-time compositional data without requiring sample extraction and offline analysis, enabling continuous process monitoring and immediate process adjustment.
2Productivity
If continuous analysis is implemented to monitor process media and process progress, then real-time process control is achieved, but a large number of analytical instruments and significant personnel resources are required
Solution Approach 1:
The patent employs a universal NIR spectroscopy system that can monitor multiple process parameters (composition, concentration, process progress) simultaneously through a single analytical instrument. This multi-functional approach eliminates the need for multiple specialized analytical instruments and reduces personnel requirements compared to traditional continuous analysis methods.
Solution Approach 2:
The patent changes the measurement parameter from traditional offline chemical analysis to online optical spectroscopy. This parameter change enables continuous monitoring with a single instrument that captures multiple process variables simultaneously, reducing both device complexity and personnel resources while maintaining real-time control capability.
3Ease of operation
If mathematical models are used for process control based on reaction stoichiometry and input variables, then process regulation is achieved, but the models exhibit excessive inaccuracies resulting in significant deviations in product concentrations
Solution Approach 1:
The patent implements a feedback control system where online NIR measurements continuously provide actual process data back to the control model. This real-time feedback allows the mathematical model to be continuously adjusted and corrected based on actual measurements, eliminating the excessive inaccuracies of open-loop models while maintaining ease of operation through automated regulation.
Solution Approach 2:
The patent uses preliminary calibration of the NIR system with known standards to establish accurate spectral relationships before actual process monitoring. This preliminary action ensures that the mathematical model starts with accurate baseline data, preventing the excessive inaccuracies that would otherwise occur during process control.
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 enables precise and economical control of the PAC production process, reducing deviations to below 0.05% and eliminating the need for subsequent cleaning processes, thereby ensuring high product quality and process stability while minimizing costs.
Implementation Method 1
by means of near-infrared analysis, in particular near-infrared spectroscopy (NIR)
Data Source
Figure 1
AI summary
The invention relates to a method for the manufacturing-related hydrometallurgical preparation or for the manufacturing-related wet-chemical conversion of a first (1) or a second starting material into a chemical reaction product and/or into a process-related by-product (7), wherein the first (1) or the second starting material is hydrometallurgically and/or wet-chemically reacted with a fluid, in particular aqueous medium, and the chemical reaction product and/or the by-product (7) is obtained in the form of a solution, which solution contains at least one in particular metal ingredient contained in the first (1) and second starting material, wherein a solution is to be created which permits a precise and economical processing, as well as a good reproducibility and a precise adjustment of the composition of the obtained by- and end-products. This is achieved in that: in the obtained solution and/or the obtained reaction product and/or the obtained by-product (7), at least the content and/or the concentration of the at least one, in particular metal ingredient and/or an ion or molecule originating from the fluid medium is continuously determined online via near-infrared analytics, in particular near-infrared spectroscopy analytics (NIR); and based on the near-infrared measurement values, in particular near-infrared spectroscopy measurement values that are determined and transferred in realtime to a mathematical control module, the control model-influenced hydrometallurgical preparation process or the wet-chemical reaction process is controlled online in an open-loop and/or closed-loop manner.