Coupled Reaction Flow Control for Fast Continuous Rate Changes
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Solution Overview
Problem
In continuous chemical production processes involving coupled reactions, achieving rapid and stable changes in production rates is challenging due to the need for precise matching of mass flows, which can lead to undesirable deviations and potential process interruptions, requiring complex and costly monitoring and intermediate storage solutions.
Innovation Solution
A process where temporary control variables are generated by a control unit to rapidly adjust the flow rates of materials during the settling-down phase, allowing regulators to settle without influencing the process, enabling quick attainment of steady-state conditions by adjusting all relevant regulating devices simultaneously based on previous knowledge and stoichiometric functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the flow rates of materials are precisely matched by regulating devices during settling-down phase, then the mass flow matching accuracy is improved, but the process stability deteriorates due to regulator oscillations and deviations
Solution Approach 1:
The patent extracts the regulating devices from the control loop during the settling-down phase by supplying them with temporary control variables instead of feedback-based control variables. This removes the regulators' influence on the process while maintaining their flow rate setting capability, preventing oscillations and instability that would otherwise occur during transient conditions.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and supplying temporary control variables to regulating devices during the settling-down phase based on stoichiometric relationships and previous process knowledge. This allows the system to anticipate required flow rate adjustments without relying on feedback regulators that could cause oscillations, thereby maintaining stability during transitions.
2Measurement precision
If regulators control flow rates during settling-down phase, then the flow rate matching is improved, but the settling time increases due to oscillations and deviations
Solution Approach 1:
The patent removes regulators from active control during settling-down by supplying temporary control variables directly to regulating devices. This extraction prevents regulator-induced oscillations and delays, allowing the system to settle much faster while still achieving accurate flow rate matching through the temporary control variables based on stoichiometric relationships.
Solution Approach 2:
The system performs preliminary calculation of appropriate flow rates using temporary control variables during settling-down, eliminating the need for regulators to gradually adjust and oscillate. This preliminary action based on stoichiometric knowledge allows immediate establishment of correct flow rate relationships, dramatically reducing settling time.
3Reliability
If intermediate storage solutions are implemented to buffer flow rate variations, then the process reliability is improved, but the device complexity and costs increase
Solution Approach 1:
The patent eliminates the need for complex intermediate storage and monitoring systems by extracting regulators from control during settling-down and using temporary control variables. This approach maintains process reliability through accurate stoichiometric-based flow rate matching without requiring additional storage infrastructure or complex monitoring equipment.
Solution Approach 2:
The system uses its own process knowledge (stoichiometric relationships and previous operating data) to generate temporary control variables, making the control system self-sufficient during settling-down. This self-service approach eliminates the need for external intermediate storage solutions and complex monitoring systems, reducing device complexity while maintaining reliability.
Data Source
AI summary
A method for continuously producing a product (A1) by way of at least two coupled-together chemical reactions (C1, C2), wherein at least two input substances (E1, E2) are fed to a first chemical reaction (C1), wherein a plurality of intermediate substances (Z1, Z2) are produced from the input substances (E1, E2) by the first chemical reaction (C1), wherein at least one of the intermediate substances (Z2) is fed to a second chemical reaction (C2), wherein the at least one fed intermediate substance (Z2) is further processed by the second chemical reaction (C2), in particular using at least one further substance (W1, W2) in a second chemical reaction (C2) to form a plurality of output substances (A1, A2), that is to say to form the chemical product (A1) and at least one further output substance (A2), wherein the flow rates (Fi) of the fed substances (E1, E2, Z1, W1, W2, A2) that are fed to one of the reactions (C1, C2) are set by a respective actuating element (VE1, VE2, VW1, VW 2, VZ 2, VA1), wherein each of the fed substances is assigned a separate actuating element, wherein a manipulated variable (SE2,R, Si,R) that is stipulated by a controller (RE2, Ri) is respectively applied to at least one of the actuating elements, wherein, for changing the production rate of the chemical product (A1), a temporary manipulated variable (SE2,temp, Si,temp) is respectively applied during a transient phase (II, III) to at least one of these actuating elements (VE2, Vi) instead of the manipulated variables (SE2, R, Si,R) stipulated by the respective controllers (RE2, Ri), wherein the temporary manipulated variable (SE2,temp, Si,temp) or the temporary manipulated variables is/are generated by at least one control unit (SE) in dependence on a default value (NV).