PROGRESS IN SLURRY PROCESSES FOR HEAVY FEEDSTOCKS UPGRADING

摘要

Among the various options available for upgrading bottoms materials, slurry processes have excellent potential particularly on high-metals feedstocks. The main limitations to their commercialization relate to the high investment and operating costs due to the severe operating conditions and/or the catalyst make-up. The metal constituent of the catalyst may be an inexpensive iron-based material or a transition metal, particularly molybdenum. The use of active catalysts may favor the process of hydrogen uptake thus promoting the upgrading reactions. However, when considering the high price of molybdenum, a 'once-through' scheme can be considered only for processes employing very low molybdenum concentrations. Alternative solutions deal with the use of higher amounts of molybdenum-based dispersed catalysts under hydrotreating conditions (low temperature), in order to promote upgrading reactions and prevent coke formation. The final product remains 'heavy' but clean from poisons and may represent a suitable charge for conventional catalytic cracking processes (FCC, RCC) or fixed bed hydrocracking. Moreover, this process configuration allows to overcome the problems associated with the catalyst cycle: different solutions for catalyst separation and recycling will be presented.