Single Particle Asphaltene Pyrolysis in a Drop-Tube Furnace
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- 作者：Satarupa Dhir ; Nirlipt Mahapatra ; Vinoj Kurian ; Mehdi Alipour ; Rajender Gupta
- 刊名：Energy & Fuels
- 出版年：2016
- 出版时间：July 21, 2016
- 年：2016
- 卷：30
- 期：7
- 页码：6132-6142
- 全文大小：712K
- 年卷期：0
- ISSN：1520-5029
文摘
Oil sands in the Athabasca and Cold Lake regions of Northern Alberta form Canada’s primary source of energy reserves. Asphaltenes, a significant part of bitumen, are often considered to be the least valuable component of crude oil due to various factors such as difficulty in transporting and processing. Very few studies have been carried out on the pyrolysis of asphaltenes in entrained flow conditions. Single particle investigations are useful since they are conducted in a well-controlled environment allowing for the elimination of complexities arising from particle–particle interactions. Char is an intermediate of the gasification process, and the structural and morphological behavior of char plays a pivotal role in determining the rate of gasification. In this work, the pyrolysis of pulverized asphaltene feedstock was carried out in a tube furnace maintained at atmospheric pressure. The effects of furnace temperature and particle size on char formation and char characteristics were investigated. Chars obtained from larger particles (1.7 mm to 850 μm) exhibited morphology similar to that of asphaltene particles while the pyrolysis of particles ranging from 250 to 425 μm at higher temperatures resulted in char with less volatile matter remaining. Scanning electron microscope (SEM) and cross-sectional images of char particles indicated the formation of cenospheres and the fragmentation of char particles at higher pyrolysis temperatures. High pyrolysis temperatures also led to a loss of active sites, an increase in alkene content, and aromatic condensation. Inductively coupled plasma mass spectroscopy (ICP-MS) and X-ray fluorescence (XRF) investigations validated the retention of K and Na along with heavy elements such as V, Ni, and Cu in char at temperatures above 700 °C. Ultimately, the combustion reactivities of char were obtained at 700, 800, and 900 °C for particles of 425–850, 355–425, and 250–355 μm, respectively, and were compared using the Flynn Wall Ozawa method.