Flare Gases Based Carbon Nanotubes (CNTs): Futuristic Materials for Energy Storage Applications

S. Watcharasing, Y. Chuminjak, C. Sriprachuabwong, P. Pavasant, P. Kiattikomol, N. Wararatkul
PTT Exploration and Production Public Company Limited (PTTEP),

Keywords: carbon nanotubes (CNTs), flare gases, energy storage, sustainability


Carbon Nanotube (CNTs), a carbon-based nanoparticle regarded as the “Futuristics Materials” for various advanced technology applications. This project aims to synthesize the high-valued CNTs product and explore opportunities to reduce greenhouse gas emission by developing a catalytic, fluidized bed reactor using process gas as the main feedstock. Previously, CNTs has been developed, on a laboratory-scale, from simulated formulation from flare gas. With the promising results, CNTs skid was mobilized and tied-in with PTTEP gas processing facility. Design Thinking concepts were used to develop the Prototype-Scale CNTs Reactor. The prototype is a low pressure, isothermal fluidized bed reactor which converts hydrocarbon gas into solid CNTs particles. A catalyst, suspended on catalyst bed support, is used to promote the conversion of the reactants within the Fluidized Bed Chemical Vapor Deposition (FBCVD), which can handle gas. To fast track the prototype testing, lean engineering development concepts were utilized to satisfy all process and safety requirements. Gas flow rate, gas composition, catalyst amount were studied in this work. CNTs have been synthesized using Chemical Vapor Deposition (CVD) which can be cost effectively adapted for large-scale, industrial production. The method results in lower reaction temperatures and higher carbon nanotube yields and purities. A Fluidized Bed CVD Reactor was applied for CNTs synthesis in this project providing simultaneous solid/fluid mixture and excellent heat and mass transfer. In laboratory phase, operating parameters such as gas composition ratio, total gas flow rate, reactor temperature, amount of catalyst, and CNTs purification method, were varied. The result shows a promising yield, and purity, and a Multi-Walled CNTs (MWCNTs) diameter of 50 nm. Therefore, CNTs synthesis from process gases in Field Trial Test was initiated, and the CNTs reactor skid was mobilized to install at PTTEP gas processing facility, routing gas from real process stream into reactor unit. Refer to actual plant conditions, the changes in the feedstock flowrate, gas compositions and temperatures, catalyst loads, and purification methods will be investigated to determine the feasibility of this novel technology. New findings and requirements discovered during the field test will be used to iteratively optimize and improve the design of the CNTs Reactor for future industrial-scale implementation. CNTs synthesis from Field Trial Test was firstly initiated in company, using process gases as carbon source for CNTs synthesis. This technology is a part of Carbon Capture and Utilization (CCU) technology which will help reduce CO2 emission to atmosphere. The synthesized CNTs product will be further applied in potential applications such as energy storage for prolong life cycle and specific capacity of energy storage.