Key Composition of Waxy Crude for Increasing Restarting Time(ABSTRACT)

摘要

Increasing restarting time window is essential for reducing the operation risk for waxy crude production and transportation. PETRONAS has been involved in developing effective reducing-risk technologies applicable to land and off-shore production and transport.This presentation will focus on significance of paraffin concentration for designing effective restarting strategies applicable to waxy crude pipeline.Cross-polarized microscopy (CPM) and high pressure gas chromatography (HTGC) was used to assess the relationship between wax appearance temperature (WAT) and alkane (C_(20)-Cgo) concentration respectively. Thermal properties of the waxy crude for a broad range of congealing temperatures were first laboratory measured and then used to assess the congealing speed under typical buried pipeline diurnal temperature conditions. A finite element (congealing) heat transfer model was further used to determine the rate of congealing as a function of local paraffin concentrations expected at different locations for a transport line. The strength of congealing zone to be experimentally assessed in the second stage of this study, was a primarily assumed here in order to model the restarting condition as simple function of congealed area of the pipeline and time.Results of this analytical and numerical-modeling study reveals the most critical operation conditions related mainly to local concentration of alkane. The double-effect of increasing the alkane concentration for extending the congealing time and restarting window and for reducing it due to increasing the WAT is discussed. A high-risk concentration zone, specific to local heat transfer conditions resulted from this study will be further assessed using a novel wax deposition loop.