The demand for fuel oil is gradually decreasing in Japan. Meanwhile, global demand for petrochemicals is annually increasing. Therefore, technologies for converting fuel oil into petrochemicals are required.
We have developed an efficient process for producing BTX (Benzene, Toluene and Xylene) from LCO (Light Cycle Oil from FCC units), which is widely used as a fuel source for heavy oil.
This FCA (Fluid Catalytic Aromaforming) process can produce BTX from LCO in the absence of hydrogen gas. LCO is composed of compounds that have various molecular structures. The important function when developing an FCA process is to optimize the reactions of each structure, so we focused on analyzing the components of LCO in detail. Catalyst deactivation due to coke formation is a major issue in the FCA process. To solve it, we employed a circulating fluid-bed reaction system to regenerate deactivated catalysts and to enable continuous reactions.
We have developed fluid bed catalysts providing high BTX yield, abrasion resistance, and fluidity by improving catalyst preparation. We have also made it possible to optimize BTX and coke yield by controlling fluid bed reaction conditions such as contact time and catalyst circulation rate. In a fluidized bed reactor, the fluidity of catalysts (which is dependent on hydrodynamic parameters such as the size of bubbles) affects the reactivity of the process. We have measured bubble diameter in a fluidized bed of FCA catalyst in order to determine its fluidity.
Furthermore, we found that the partial hydrogenation of LCO as pretreatment is an effective method to increase the BTX yield of FCA process.