Heat-Exchanger Deposition in an Inverted Steam-Assisted Gravity Drainage Operation. Part 1. Inorganic and Organic Analyses of Deposit Samples

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• 作者：David W. Jennings ; Arif Shaikh
• 刊名：Energy & Fuels
• 出版年：2007
• 出版时间：January 2007
• 年：2007
• 卷：21
• 期：1
• 页码：176 - 184
• 全文大小：1410K
• 年卷期：v.21,no.1(January 2007)
• ISSN：1520-5029

文摘

Heat-exchanger fouling is a severe operational problem in steam-assisted gravity drainage (SAGD) processes.In an effort to better understand which species are prone to deposit and gain insights into means for mitigatingSAGD heat-exchanger deposition, analyses were performed on a series of heat-exchanger deposit samplesfrom an inverted SAGD operation in Canada. Deposit samples were obtained from each of five heat-exchangerbanks used in the operation of the facility: exchangers heating the produced raw bitumen reverse emulsioncoming from the wells (two exchanger banks in series) and exchangers cooling separated produced waterleaving the high-temperature separator (HTS) (three exchanger banks in series). The separated produced waterleaving the facility HTS was also analyzed. The analyses focused on determining the overall inorganic andorganic elemental compositions, as well as providing general information on the type of chemical speciespredominately present. The analyses performed on the deposits and solids from the produced water included(1) carbon, hydrogen, and nitrogen analyses, (2) X-ray fluoresence, (3) X-ray diffraction, (4) thermogravimetricanalyses, (5) chloroform/methanol/toluene solubilities, and (6) Fourier transform infrared spectroscopy. Ionchromatography and inductively coupled plasma analyses were also run on the water sample. Analyses indicatedpreferential deposition of particular species and potential causes of deposition in certain exchangers. For theSAGD operation, at that time, a periodic slop-tank recycle containing warm lime softener sludge was indicatedas a source of a significant amount of fouling in the heat exchangers handling the produced bitumen reverseemulsion and the initial exchanger cooling separated produced water leaving the HTS. High Mg⁺² and Si⁺⁴compositions were detected in these deposits. Magnesium silicates were indicated in Fourier transform infraredspectroscopy analyses. Deposition of additional other sand/silicates was also indicated. For the organic portionof these deposits, significant concentrations of organic acids and organic acid salts were indicated within thedeposit hydrocarbons. Although all deposits contained both inorganic and organic components, the deposits inthe last two exchangers cooling the produced water were found to be predominately organic. Significantconcentrations of organic acids and organic acid salts were also indicated in these deposits. The indications ofa significant organic acid/acid salt content led to collaboration work with the National High Magnetic FieldLaboratory to study these components in detail. Electrospray ionization Fourier transform ion cyclotron resonancemass spectroscopy work performed at the National High Magnetic Field Laboratory is discussed in the part 2companion paper (Schaub, T. M.; Jennings, D. W.; Kim, S.; Rodgers, R. P.; Marshall, A. G. Energy Fuels2007, 21, 185-194) of this series.