Dynamic Compressor Recirculation Control for Flow Turndown Stability
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Solution Overview
Problem
Compressors experience performance issues and instability during large flow turndowns, leading to drops in outlet pressure and potential stalling, especially in applications with fluctuating power inputs from renewable energy sources.
Innovation Solution
A dynamic compressor system with variable features such as a flow extractor, flow injector, variable area choke, and inlet guide vane, which adjust operational parameters in real time to maintain outlet pressures and flow rates within target ranges by recirculating a portion of the flow and mixing it with the inlet stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the compressor operates at low inlet flow rates during large flow turndown, then the compressor can accommodate fluctuating power inputs, but the outlet pressure drops and stable operation becomes difficult to maintain
Solution Approach 1:
A recirculation stream is introduced as an intermediary flow path. The system extracts a portion of the outlet stream and recirculates it back to the inlet, creating an intermediate flow that maintains compressor stability during low inlet flow conditions. This recirculation stream acts as a mediator between the inlet and outlet, ensuring continuous stable operation despite fluctuating external flow demands.
Solution Approach 2:
The system employs variable flow extraction and injection mechanisms that can dynamically adjust the recirculation flow rate based on operating conditions. The flow extractor and injector are configured to vary the amount of recirculated flow, allowing the system to adapt to different inlet flow rates while maintaining stable compressor operation and outlet pressure within target ranges.
2Adaptability or versatility
If traditional recirculation is used to adapt to flow turndown, then the compressor can operate at lower flow rates, but the output pressure drops
Solution Approach 1:
The system dynamically adjusts multiple operating parameters simultaneously including recirculation flow rate, compressor rotational speed, and flow distribution ratios. By coordinating changes in these parameters, the system maintains outlet pressure within target ranges while accommodating varying inlet flow rates, preventing the pressure drop that occurs with traditional recirculation approaches.
Solution Approach 2:
The controller receives feedback on outlet pressure, inlet flow rate, and recirculation flow rate to dynamically adjust system operations. This feedback mechanism allows the system to compensate for pressure drops by adjusting recirculation flow and compressor speed, ensuring outlet pressure remains within the target range despite changes in operating conditions.
3Adaptability or versatility
If the compressor speed is reduced to accommodate low flow rates, then the compressor can operate during flow turndown, but the outlet pressure decreases
Solution Approach 1:
The system segments the outlet stream into two separate paths: the system outlet stream and the recirculation stream. This segmentation allows the compressor to maintain higher rotational speeds while still accommodating low inlet flow rates, as the recirculation stream provides additional flow through the compressor. The segmented flow paths enable independent control of each stream, maintaining outlet pressure while adapting to varying flow demands.
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
The system effectively maintains stable compressor operation and prevents stalling during high levels of flow turndown, ensuring consistent outlet pressure and flow rates without the need for rotational speed changes or additional power storage, thus optimizing performance in renewable energy-driven processes.
Implementation Method 1
a variable flow extractor positioned downstream of the compressor to extract or split the flow from the compressor outlet into a recirculation stream and a system outlet stream
Implementation Method 2
a variable flow injector positioned upstream of the compressor to inject or mix the recirculation stream into the compressor inlet
Data Source
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AI summary
Provided herein are dynamic compressor (102) systems and methods of operation. A compressor system (100) comprises a compressor (102) and a variable flow extractor (110) disposed downstream of the compressor (102) to split a compressor outlet stream (108A) into a recirculation stream (112A) and a system outlet stream (114A). A variable flow injector (122) disposed upstream of the compressor (102) that mixes the recirculation stream (112A) with a system feed stream (128A) to form a compressor inlet stream (106A). A controller (150) is configured to receive first data indicative of a pressure of the system outlet stream (114A), second data indicative of a pressure of the system feed stream (128A), and third data indicative of flow rates of at least two of the system feed stream (128A), the system outlet stream (114A), and the recirculation stream (112A). The controller (150) adjusts a flow rate of the recirculation stream (112A) via the variable flow extractor (110) and the variable flow injector (122) based on the first, second, and third data.