In the petroleum industry, cyclonic separators are acceptable as hydrocyclone, mist eliminators, separator internal device and compact metering package. Weight and small footprint requirements for applications such as subsea separation, downhole separation, and compact gas monetization systems is driving interest in using cyclonic separator for bulk gas-liquid separation. Unfortunately, the challenge of coping with the effect of unsteady inlet flow behaviour on the separator performance limit it acceptance for bulk gas-liquid separation. Fundamental understanding of the flow behaviour inside the separator under various inlet flow conditions is required to deal with the challenge. While most published work have addressed flow behaviour in the lower half of cyclonic separator, this thesis concentrated on the upper half. A gas-liquid pipe cyclonic separator was setup at Cranfield University for bulk gas-liquid separation. Large amount of data at the inlet and upper part of the separator were acquired using electrical resistance tomography (ERT), wire meshes sensor (WMS), conductivity hold up probe and pressure transducers. The acquired data were used in analysing flow regimes, upward swirling liquid film (USLF), zero-net liquid flow (ZNLF), liquid holdup and, general separator performance. It was found from analysis of USLF data that a maximum USLF height exists for every constant superficial liquid velocity. A correlation based on dimensionless numbers was proposed for predicting this height. Experimental results on ZNLF showed that a critical ZNLF also exist above which liquid carryover can take place. The liquid holdup for this critical ZNLF was measured under separator operating condition using ERT and a correlation for predicting the liquid holdup was proposed. Four flow regimes were identified as swirling annular, light-mist heavy-mist and churn using visual observations, ERT, WMS and pressure transducer. A flow regime map was proposed based on gas and liquid Froude number. The performance based on the operating envelope for liquid carryover and pressure drop for horizontal and 270 downward inclined tangential inlet was compared. It was concluded that the separation performance was marginally improved by using an inclined tangential inlet. The pressure drop for the inclined inlet was far greater than that of horizontal inlet. Two inlet nozzles with D–shape were used for separation enhancement. The nozzle that reduces the diameter of full pipe bore by 25% gave slight improvement but also gave the greatest pressure drop. The nozzle that reduced the full pipe bore diameter by 50% performed poorly.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:683896 |
| Date | January 2015 |
| Creators | Kanshio, Sunday |
| Contributors | Yeung, Hoi |
| Publisher | Cranfield University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://dspace.lib.cranfield.ac.uk/handle/1826/9847 |
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