Conversion of Petroleum Coke into Valuable Products using Catalytic and Non-Catalytic Oxy-Cracking Reaction
Date
2018-04-20
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Abstract
Every year millions of tons petroleum coke (petcoke) is generated as a by-product from bitumen and heavy oil upgrading due to the increasing demand in energy. Petcoke is a carbonaceous solid consisting of polycyclic aromatic hydrocarbons with low hydrogen content, derived from the processing of oil sands and oil refineries. The upgrading and treating of petcoke typically include thermal techniques such as gasification and combustion. However, several challenges limit the effectiveness of these conventional processes such as sulfur and CO2 emissions as well as high energy and costs associated with low efficiency. Therefore, finding an alternative, efficient, environmentally-friendly and cost-effective technology to treat these massive amounts of petcoke is needed. In this study, an oxy-cracking technique, which is a combination of oxidation and cracking reactions, is introduced as an alternative approach for petcoke utilization. This oxy-cracking takes place in basic aqueous media, at mild operation temperatures (170-230 oC) and pressures (500-600 psi). The oxy-cracking reaction mechanism was investigated using Quinolin-65 (Q-65) as a model molecule mimicking the residual feedstocks. Theoretical calaculations along with experimental reaction were carried out on Q-65 to explore the reaction pathways. Consequently, several operating conditions on petcoke oxy-cracking were investigated, such as temperature, oxygen pressure, reaction time, particle size and mixing rate to optimize the solubility and selectivity of oxy-cracked products. To enhance the oxy-cracking reaction conversion, an in-house prepared copper-silicate catalyst was introduced and characterized using BET, SEM, FTIR and XRD techniques. The oxy-cracking technique successfully converted the petcoke into valuable products, particularly humic acids analogs with other functional groups such as carboxylic, carbonyl, and sulfonic acids, as confirmed by FTIR, XPS and NMR analyses, in addition to minimal emission of CO2. Interestingly, based on the experimental findings, the metal contents in the obtained oxy-cracked products are significantly lower than that in the virgin petcoke. Consequently, the heating value and oxidation behaviour of the oxy-cracked products was investigated using TGA. These results showed that the oxy-cracked petcoke is easier and faster to oxidize compared to the virgin petcoke, suggesting that the oxy-cracked petcoke could be an alternative-clean fuel for power generation.
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Keywords
oxy-cracking, residual feedstock, petroleum coke, quinolin-65 (Q-65), copper-silicates, humic acids, oxidation, gasification
Citation
Manasrah, A. D. (2018). Conversion of Petroleum Coke into Valuable Products using Catalytic and Non-Catalytic Oxy-Cracking Reaction. (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/31818