Design and development of adsorbents for petroleum industry pollutants

Abstract

Global use of petroleum has reached its critical limit, and hazardous pollutants that are being released to atmosphere or surrounding affects at a global scale. With 90 million barrels of petroleum being used globally on a daily basis, the slightest increase in the efficiency in adsorption will greatly reduce the amount of global pollutants to environment. This study focuses on reducing the release of $CO_2$ to atmosphere, the release of various heavy metals such as copper, zinc, lead cadmium and nickel in wastewater effluent, and the release of mercury content from gas condensate. One of the major $CO_2$ releasing process in the petroleum industries occur in steam methane reformer unit, converting hydrocarbon to $H_2$ and $CO_2$ . With high and low temperature $CO_2$ adsorption conditions in steam methane reformer unit, adsorbent for both conditions were investigated. $Li_4SiO_4/TiO_2$ nanotube complex was designed to be used for high temperature $CO_2$ adsorption in steam methane reformer. Lithium silicate, through a chemisorption mechanism, is a promising $CO_2$ adsorbent due to its large $CO_2$ capacity at high temperature and low materials cost. However, the conventional non-porous $Li_4SiO_4$ shows poor $CO_2$ adsorption kinetics. By using $TiO_2$ nanotube as a channel for lithium ion transfer in the $Li_4SiO_4$ structure, the complex receives significant enhancement in sorption kinetics. For low temperature $CO_2$ adsorption application, covalent organic polymer $(COP10_9)$ with TETA amine impregnation was developed. Amine impregnation increases the polymer’s affinity towards $CO_2$ for chemical adsorption in humid conditions through bicarbonate formation. One of the most critical environmental concern arises from the heavy metal release due the petroleum extraction and refinery process of gas condensate. In the extraction process, heavy metals such as cadmium, lead, copper, zinc and nickel are combined with water effluents and bio-accumulates in large bodies of water. Thus, a disulfide linked porous covalent organic polymer, COP-63 was developed as a functionalized adsorbent that contains high surface area and selectivity towards heavy metal ions. For the application in mercury adsorption in gas condensate, disulfide linked swellable covalent organic polymer COP-65 was studied. After proving its effectiveness in mercury removal from gas condensate in the Saudi-Aramco’s R&D center, its scale-up production as well as pilot plant was designed for commercialization.