| 摘要 |
Compressors for processes, as used for refrigeration systems applied to ethylene production, are multiple stage machines; furthermore, sidestreams enter/exit between the stages. Since a flow measurement device is not available between stages, and the gas temperature entering most stages is unknown, it is difficult to calculate an accurate value for reduced flow for antisurge control purposes. A new method is described, whereby reduced flow alone is replaced by the product of the reduced flow and the equivalent speed. This allows accurate calculation of the distance of the operating point to the surge line since the inlet temperatures into the separate compression units (except the first) are not necessary. The invention described herein can be applied to multistage compression systems for a variety of processes.
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