Mixed Refrigerant Compression Circuit with Parallel First-Stage Bodies
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Solution Overview
Problem
Current refrigerant compression circuits for natural gas liquefaction are limited by the maximum volumetric flow rate of single large compressors, restricting LNG train capacities to below 5.5 million tonnes per annum, and existing solutions like parallel compression strings increase capital costs.
Innovation Solution
A refrigerant circuit design featuring a first compression stage with two parallel compressor bodies for splitting and recombining the refrigerant flow, followed by a single compressor body for the second stage, allowing for more even volumetric flows and reduced compressor body count, thereby increasing capacity without parallel strings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single large compressor body is used to increase volumetric flow rate, then productivity increases, but device complexity and capital cost increase due to reaching maximum available sizes
Solution Approach 1:
The first compression stage is divided into two separate parallel compressor bodies instead of using a single large compressor. This segmentation allows the system to handle higher volumetric flow rates by distributing the compression load across multiple smaller, more manageable compressor units, thereby increasing productivity without requiring an excessively large single compressor body
2Productivity
If parallel compression strings are used to overcome maximum compressor flow limits, then productivity increases, but device complexity and capital cost increase due to duplicating entire compression systems
Solution Approach 1:
The compression system is segmented such that only the first compression stage uses parallel compressor bodies, while the second compression stage uses a single compressor body. This partial segmentation approach increases volumetric flow rate capability without requiring complete duplication of the entire compression system, thereby improving productivity while limiting the increase in device complexity
Solution Approach 2:
The two parallel compressor bodies from the first compression stage are merged back into a single combined stream before entering the second compression stage. This merging allows the system to benefit from the increased flow capacity of parallel compression while consolidating the system configuration, reducing the overall complexity compared to maintaining separate parallel compression strings throughout
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 design enhances energy efficiency and reduces capital costs by allowing higher LNG train capacities up to 6.5 million tonnes per annum with fewer compressor bodies and more even suction volumetric flows, improving overall efficiency and reducing energy consumption.
Implementation Method 1
a first compression stage for compressing a mixed refrigerant gas from a first pressure to a second pressure
Implementation Method 2
a first distribution means for splitting the mass flow of refrigerant gas to the first stage of compression across the at least two parallel compressor bodies
Implementation Method 3
a first merging means for recombining the first stream of refrigerant gas with the second stream of refrigerant gas to form a combined stream
Data Source
AI summary
A refrigerant circuit includes a first compression stage for compressing a mixed refrigerant gas, the first compression stage including at least a first compressor body and a second parallel compressor body, each compressor body including a suction inlet and an outlet, a first distribution means for splitting the flow of refrigerant gas to the first stage of compression across the at least two parallel compressor bodies, such that a first stream of refrigerant gas is fed to the suction inlet of the first compressor body and a second stream of refrigerant gas is fed to the suction inlet of the second compressor body, a second compression stage for compressing the mixed refrigerant gas, and a first merging means for recombining the first stream of refrigerant gas with the second stream of refrigerant gas downstream of the first compression stage for delivery to the second compression stage.