SOEC Ejector Pressure Control Across Partial Load Operation
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Solution Overview
Problem
The limited controllability of ejectors in SOEC systems, which are designed for main operating points and struggle to maintain reliable operation across partial load ranges due to fixed characteristics, necessitates improved control mechanisms for pressure and mass flow regulation.
Innovation Solution
Incorporating a control gas supply portion with valve arrangements to adjust the introduction of control gas into both the primary and secondary portions of the ejector, allowing for stepless control of pressure and mass flow, and using carbon dioxide as a control gas to enhance controllability, especially in co-electrolysis systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an ejector with fixed shape is used to increase pressure level of primary flow, then pressure increase and recirculation rate are achieved at maximum operating point, but controllability is limited and reliable operation across partial load ranges cannot be maintained
Solution Approach 1:
The patent introduces a control gas supply portion that dynamically adjusts the operation of the ejector by supplying control gas to the mixing chamber. This allows the ejector to adapt its performance characteristics across different operating points, transforming it from a static component with fixed characteristics to a dynamically controllable device that can maintain reliable operation across partial load ranges while preserving pressure increase capability.
2Manufacturing precision
If ejector is designed for main operating point, then optimal pressure increase is achieved at that point, but operation at partial load ranges becomes unreliable
Solution Approach 1:
The patent changes the operational parameters of the ejector by introducing control gas into the mixing chamber. This parameter change allows the ejector to maintain optimal performance across different operating conditions, enabling reliable operation at partial load ranges while preserving the design optimization for main operating points.
3Adaptability or versatility
If control gas is supplied to mixing chamber to improve controllability, then pressure and mass flow control is enhanced, but device complexity increases
Solution Approach 1:
The patent uses control gas as an intermediary substance to achieve controllability of the ejector. By introducing this intermediate medium into the mixing chamber, the system gains enhanced pressure and mass flow control capabilities without requiring complex mechanical adjustment mechanisms, thus limiting the increase in device complexity.
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 solution significantly improves the controllability of the ejector across varying load states, extending the operating range and maintaining efficient recirculation rates by dynamically adjusting the control gas distribution between the primary and secondary sides.
Implementation Method 1
the primary flow attains a high speed in the ejector nozzle and the outflowing jet generates a negative pressure in a mixing chamber of the ejector
Implementation Method 2
The negative pressure causes the secondary flow to be entrained and admixed with the primary flow on account of a suction effect
Implementation Method 3
a control gas supply portion for supplying control gas into the primary portion and into the secondary portion in order to control a pressure and/or mass flow in the primary portion and in the secondary portion
Implementation Method 4
wherein the control gas supply portion comprises a valve arrangement for controlling the pressure and/or the mass flow in the primary portion and in the secondary portion
Data Source
AI summary
The present invention relates to an SOEC system (1), comprising a fuel cell stack (2) having a gas side (3) and an air side (4), and an ejector (5) for supplying a process fluid to a gas inlet (6) on the gas side (3), wherein the ejector (5) comprises a primary inlet (7), for introducing a water-containing primary process fluid through a primary line (8) of the SOEC system (1) into a primary portion (9) of the ejector (5), and a secondary inlet (10), for introducing recirculated secondary process fluid through a recirculation line (11) of the SOEC system (1) from a gas outlet (12) on the gas side (3) into a secondary portion (13) of the ejector (5), wherein the SOEC system (1) further comprises a control gas supply portion (14) for supplying control gas into the primary portion (9) and into the secondary portion (13) in order to control a pressure and/or mass flow in the primary portion (9) and in the secondary portion (13), and wherein the control gas supply portion (14) comprises a valve arrangement (19, 20) for controlling the pressure and/or the mass flow in the primary portion (9) and in the secondary portion (13).The invention further relates to a method for operating an SOEC system (1) according to the invention.