Multistage Compressor-Expander Turbomachine Stacked Shaft
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Solution Overview
Problem
Existing integral compressor-expander arrangements face challenges in achieving efficient energy recovery and optimal operation, particularly in maintaining high power ratings without compromising reliability due to centrifugal forces.
Innovation Solution
The turbomachine design features a stacked shaft with turboexpanders and compressor impellers mounted integrally with the shaft portions, allowing for higher rotational speeds and eliminating the need for external electric machines. This configuration includes serially arranged turboexpanders for efficient energy recovery and stacked impeller mounting for enhanced reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If impellers are mounted in shrink-fit configuration on the shaft, then the assembly is simple and compact, but the impeller-shaft coupling may loosen due to centrifugal forces at high rotational speeds
Solution Approach 1:
The shaft is divided into multiple segments with impellers mounted on each segment. The impellers are secured using keyed connections that engage with keyways in the shaft segments, providing positive mechanical coupling that prevents loosening at high rotational speeds while maintaining assembly simplicity.
2Device complexity
If a single turboexpander is used to drive the compressor sections, then the device complexity is reduced, but the power rating is limited and energy recovery efficiency is compromised
Solution Approach 1:
The power generation system is segmented into multiple turboexpanders (first and second turboexpanders) that operate in parallel on the common shaft. Each turboexpander handles a portion of the gas flow and contributes to the total power output, enabling high power ratings while maintaining manageable device complexity and improving energy recovery efficiency.
3Object-affected harmful factors
If the shaft is sealed to the casing arrangement, then leakage is prevented, but the shaft cannot rotate freely and external electric machines cannot be connected
Solution Approach 1:
The shaft is extracted from the sealed casing arrangement, allowing it to rotate freely without sealing constraints. This enables the connection of external electric machines and maintains operational flexibility while the turboexpanders and compressor sections are housed within the sealed casing to prevent gas leakage.
4Ease of operation
If external electric machines are used to drive the compressor sections, then operational flexibility is maintained, but energy recovery efficiency is reduced due to power losses
Solution Approach 1:
The turboexpanders and compressor sections are merged into a single integrated drive system on a common shaft. The turboexpanders directly drive the compressor sections through the shared rotating shaft, eliminating intermediate power transmission losses and improving overall energy recovery efficiency while maintaining operational flexibility through the integrated design.
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 achieves efficient energy recovery and high power ratings while ensuring reliable operation at high rotational speeds, eliminating the risk of impeller-shaft coupling loosening due to centrifugal forces and reducing leakage through a sealed casing arrangement.
Implementation Method 1
a first turboexpander and a second turboexpander mounted on the shaft for rotation therewith in the casing arrangement, adapted to generate mechanical power by expanding a gaseous flow therethrough
Data Source
Figure 1
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Figure 4~5
AI summary
The turbomachine comprises a casing arrangement and a shaft supported for rotation therein. The shaft is rotatingly supported by a first and second bearing unit. First and second compressor sections are provided in the casing arrangement. The first compressor section comprises a first compressor impeller mounted on the shaft for rotation therewith, and the second compressor section comprises a second compressor impeller mounted on the shaft for rotation therewith. The turbomachine further comprises a first turboexpander and a second turboexpander mounted on the shaft for rotation therewith in the casing arrangement.