Conversion of Petroleum Coke to Porous Materials
Date
2019-12-13
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Petroleum coke (petcoke) is a low value by-product from oil and gas refinery. The production of oil sand petcoke has been continually increasing over the last 20 years. However, only 11-20% of the petcoke produced has been utilized as site fuel. The remainder has been largely stockpiled in northern Alberta. As oil sand petcoke contains higher carbon but a lower ash content compared to conventional crude oil petcoke, this project was designed to prepare porous carbon materials from petcoke. The aim of this thesis was to develop methods to convert by-products from oil refinery (eg. petcoke and asphaltenes) to value-added porous carbon materials. In order to combine nanoscale pores and macroscale pores into one monolithic structure, activation was proposed to develop micro and mesopores on oil sand petcoke as a first step. Both chemical activation (using KOH/NaOH) and chemical steam co-activation were studied to prepare activated carbon (AC) from petcoke. A salt template was then utilized to form macroscale pores between AC particles for hierarchical porous carbon (HPC) preparation. The co-activation of KOH and steam reduced the chemical agent amount without compromising pore volume. Before steam was introduced into the system, a molten phase around petcoke particles is presumed to be formed. A greater amount of chemical agent corresponded to a thicker molten chemical layer, which restricted the rate of steam gasification. By lowering the activation temperature to 500 ˚C, a 0.34 cm3/g pore volume and 800 m2/g surface area were obtained with an AC yield of 94%. Since there was almost no carbon consumption, the pores developed at 500 ˚C were most likely due to the opening of initial closed pores of petcoke. Finally, by using asphaltenes as natural binders to connect non-washed AC particles, HPC was fabricated with multiple scale pores after washing away the salts. The experimental results in this thesis provide feasible approaches to prepare porous materials from petcoke and asphaltenes. A better understanding of pore development during the activation process will help to optimize the process and control the properties of the final product.
Description
Keywords
Citation
Wu, J. (2019). Conversion of Petroleum Coke to Porous Materials (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.