Parallel Reactor Flow Control via Passive Restrictors
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Solution Overview
Problem
Existing systems for operating parallel reactors face challenges in accurately controlling flow distribution and pressure in high throughput experimentation, particularly due to the limitations of active flow controllers and the need for high pressure drops across passive flow restrictors, which can lead to uneven flow distribution and increased system complexity.
Innovation Solution
A system comprising passive flow restrictors with equal resistance and individually controllable backpressure regulators in each reactor effluent line, connected to a pressure control arrangement that maintains consistent feed line pressures across all reactors, ensuring equal fluid distribution and pressure control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If active flow controllers (needle valves) are used to control flow rate to individual reactors, then flow rate can be changed during experiment, but the controllers are bulky, expensive, and hard to use in small parallel reactor feed lines
Solution Approach 1:
The patent removes active flow controllers from the system entirely and replaces them with a passive flow distribution system using a flow splitter and capillary tubes. This extraction eliminates the complexity, cost, and bulk associated with active controllers while maintaining flow control capability through passive resistance elements.
Solution Approach 2:
The system uses self-regulating passive flow control where capillary tubes with fixed resistance automatically distribute flow based on pressure differences. The backpressure regulators automatically maintain equal pressure at reactor inlets without active control, allowing the system to self-regulate flow distribution without external intervention.
2Manufacturing precision
If passive flow restrictors with high resistance are used to ensure equal flow distribution, then flow distribution accuracy improves, but pressure drop across restrictors must be very high leading to increased system pressure requirements
Solution Approach 1:
The patent segments the flow control function into two separate components: flow distribution (handled by the flow splitter with capillary tubes) and pressure regulation (handled by individual backpressure regulators at each reactor). This segmentation allows each component to operate at optimal pressure levels without requiring excessively high system pressure.
Solution Approach 2:
Instead of controlling flow by creating high pressure drops at the inlet (traditional approach), the patent inverts the control strategy by regulating pressure at the outlet of each reactor line. This allows flow distribution to occur at lower pressures while maintaining accuracy through outlet pressure control.
3Measurement precision
If active flow controllers with flow sensors are used, then flow rate can be monitored and adjusted, but sensors are sensitive to drift during long experiments requiring repeated calibration
Solution Approach 1:
The patent replaces expensive, drift-prone active flow sensors with simple, stable passive flow resistance elements (capillary tubes). These passive elements have no moving parts or electronic components that can drift, providing stable flow control throughout long experiments without calibration requirements.
4Ease of operation
If multiple active flow controllers are used for each reactor, then individual flow control is achieved, but the cost and complexity of the system increases significantly
Solution Approach 1:
The patent makes the backpressure regulators multi-functional by having them simultaneously perform pressure regulation and flow control functions. Each regulator maintains equal pressure at reactor inlets, which automatically ensures equal flow distribution, eliminating the need for separate flow control devices.
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 achieves precise control of flow distribution and pressure, reducing variations to less than 1% and maintaining accurate reaction conditions, even with changes in pressure drop over reactors, thereby enhancing the efficiency and reliability of high throughput experiments and production processes.
Implementation Method 1
passive flow restrictors...which have an substantially equal resistance to fluid flow
Implementation Method 2
individually controllable backpressure regulator in each effluent line...adapted to control the pressure in the reactor effluent line in which it is arranged
Data Source
AI summary
A system for operating parallel reactors includes a plurality of reactor assemblies, each reactor assembly including: a flow-through reactor, a reactor feed line, a reactor effluent line, a primary fluid source, and a flow splitter which is arranged downstream of the primary fluid source and upstream of the reactor assemblies. All passive flow restrictors have an substantially equal resistance to fluid flow. A feed line pressure measurement device and a pressure control arrangement controls backpressure regulators such that the measured feed line pressure becomes substantially the same as a feed line pressure setpoint in the reactor assemblies.