Techno-economic analysis of pressurized oxy-fuel combustion of petroleum coke

Abstract

Petroleum coke (petcoke) is a by-product of heavy petroleum refining, with heating values comparable to that of coal. It is readily available in oil-producing countries such as the United States of America (USA) and the Kingdom of Saudi Arabia (KSA) at minimum costs and can be used as an inexpensive fossil fuel for power generation. Oxy-petcoke combustion is an attractive CO2 capture option as it avoids the use of additional absorption units and chemicals, and results in a CO2 + H2O flue gas stream that is compressed and dehydrated in a CO2 capture and purification unit (CO2CPU). The additional cost of the CO2CPU can be reduced through high pressure combustion. Hence, this paper reports a techno-economic analysis of an oxy-petcoke plant with CO2 capture simulated at pressures between 1 and 15 bars in Aspen Plus™ based on USA and KSA scenarios. Operating at high pressures leads to reduced equipment sizes and numbers of units, specifically compressors in CO2CPU, resulting in increased efficiencies and decreased costs. An optimum pressure of ∼10 bars was found to maximize the plant efficiency (∼29.7%) and minimize the levelized cost of electricity (LCOE), cost of CO2 avoided and cost of CO2 captured for both the USA and KSA scenarios. The LCOE was found to be moderately sensitive to changes in the capital cost (∼0.7% per %) and increases in cost of petcoke (∼0.5% per USD/tonne) and insensitive to the costs of labour, utilities and waste treatment.