Evaluation of Light-Off Limits for a Novel Oxy-Combustion Process for Enhanced Oil Recovery (EOR)

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• 作者：Christopher R. Shaddix ; Ethan S. Hecht ; William G. Houf ; Charles K. Westbrook ; Lynn Tessier ; Fred Schneider
• 刊名：Energy & Fuels
• 出版年：2013
• 出版时间：June 20, 2013
• 年：2013
• 卷：27
• 期：6
• 页码：3438-3445
• 全文大小：344K
• 年卷期：v.27,no.6(June 20, 2013)
• ISSN：1520-5029

文摘

A pressurized oxy-fuel burner is being developed for the down-hole generation of hot CO₂ and steam for direct injection into heavy oil deposits or depleted oil reservoirs. This approach offers efficiency benefits and reduced CO₂ emissions in comparison to existing technologies that rely on steam generation at the surface. Furthermore, a burner-stabilized flame provides much better process control and generates an improved oil product relative to in situ combustion of the oil. A simple, low-temperature chemical ignition system for this process is desired, instead of using an electrical ignition system that would need to be retracted from the combustion chamber. In the work reported here, several approaches to low-temperature chemical ignition have been explored. First, the autoignition of different short-length alkanes in oxygen was measured at 11 bar, the relevant pressure for down-hole light-off. Comparison of the experimental results with computed autoignition delay, using the best-available chemical kinetic mechanisms, shows good agreement. To further reduce reactant preheating requirements, two commercial cetane enhancers, 2-ethyl-hexyl-nitrate (2-EHN) and di-tert-butyl-peroxide (DTBP), were mixed with n-pentane and n-hexane and found to lower the autoignition temperature from 350 to 240 掳C. Newly developed chemical kinetic mechanisms for 2-EHN and DTBP yield ignition delay predictions that show good agreement with the experimental autoignition measurements. The modeling predicts an autoignition temperature as low as 205 掳C for a 50鈥?0 mixture of DTBP in n-pentane.