Modular Compressor Train for Variable Suction Conditions
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Solution Overview
Problem
Current compressor arrangements for LNG carriers face efficiency limitations due to variable suction conditions, requiring different multi-stage compressors for varying boil-off gas conditions and consumer demands, leading to cumbersome and costly setups, with existing solutions like variable frequency drives not always maintaining required mass flow and potentially reaching critical speed levels.
Innovation Solution
A modular compressor train philosophy with independently operable compressor modules that can be bypassed, allowing flexible operation based on pressure, temperature, and composition, optimizing efficiency by selecting the number of modules in use according to load and suction conditions, and incorporating cooling units and antisurge lines for enhanced flexibility and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a standard approach is selected to provide one fuel gas compressor sized to supply gas to consumers with the most constraining suction conditions, then the compressor can handle the worst-case scenarios, but the compressor performance deteriorates under variable suction conditions and is not optimized for all operating cases
Solution Approach 1:
The compressor system is divided into multiple independent compressor modules that can be selectively operated based on suction conditions. Each module is optimized for specific operating ranges, allowing the system to maintain high efficiency across variable conditions by activating only the necessary number of modules.
Solution Approach 2:
The system dynamically adjusts the number of active compressor modules based on real-time suction conditions (temperature, pressure, composition). This dynamic configuration allows the compressor arrangement to adapt to varying operational requirements while maintaining optimal efficiency for each operating point.
2Use of energy by moving object
If variable frequency drive is used to optimize compressor head and efficiency through driver speed adjustment, then compressor efficiency improves, but mass flow cannot be maintained and critical speed levels are reached affecting mechanical integrity
Solution Approach 1:
Instead of using variable frequency drive on a single compressor, the system segments the compression function into multiple modular units. Each module operates at its optimal speed within a narrow range, avoiding the mechanical issues associated with wide speed variation while maintaining overall system efficiency through modular configuration.
3Productivity
If different multi-stage compressors are provided for different BOG conditions and consumers, then each compressor is optimized for its specific condition, but the compressor arrangement becomes cumbersome and costly
Solution Approach 1:
Multiple compressor modules are designed with universal functionality to handle different BOG conditions (cold, warm, high pressure, low pressure). Each module can operate under various suction conditions, allowing a single standardized module design to replace multiple specialized compressors, thereby reducing complexity and cost while maintaining performance optimization.
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
Maintains compressor efficiency across a wide range of suction conditions, reduces power consumption, and allows for optimized operation by adjusting the number of active modules, thereby addressing the inefficiencies and cost issues associated with traditional multi-stage compressor arrangements.
Implementation Method 1
a compressor arrangement for pressurizing the vaporized gas
Implementation Method 2
pressurized gas is cooled by conducting the gas through a cooling unit arranged in the bypass line
Implementation Method 3
at least a part of the pressurized gas of the compressor module is returned to the inlet of the compressor module via an antisurge line
Data Source
AI summary
The invention relates to a method for providing pressurized gas from a source of liquefied gas to a consumer (8), wherein vaporized gas is supplied from the source of liquefied gas (1) through a main input line (2) to a compressor arrangement (300) for pressurizing the vaporized gas, the compressor arrangement (300) comprising a plurality of compressor modules (3, 5, 31, 51), each compressor module being able to operate independently from any other compressor module of the compressor arrangement (300), one or more of the compressor modules (5, 51) of the compressor arrangement (300) can be bypassed, and wherein gas is conducted through only a part or all of the compressor modules depending on at least one of pressure level, temperature level, mass flow and composition of the gas to be provided to the consumer (8).