Studding the effects of different additives on the textural properties of RCD catalyst support

Hydrotreating is called to the reactions that upgrading of hydrocarbon products is the targets, and removing pollutants is done under Hydrogen gas pressure and at present of catalysts, such as hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodematalization (HDM), hydrodehalidation (HDH), or physical properties improving. In this process, gamma alumina catalyst is mostly used as the catalyst support, and nickel and molybdenum as an active metals are homogenously impregnated it. However, catalyst support should have proper surface area and pore distribution for the catalytic hydrotreating process. Concentration and specification of the oil fractions are changing with increasing the boiling point of the oil fractions. Heavy oil fractions have maximum amount and the most resistant of sulfur compounds. Hydrodesulfurization of the atmospheric residual (AR) is the most important process in the preparing low sulfur vacume gas oil (V. G. O). There are various methods to control the pore volume. One of the most effective methods to prepare large pore catalyst support is to use some additives. Physical properties of the applied residual oil hydrotreating catalysts are conformity with the specific conditions of oil fractions. Pore volume, pore diameter, and pore distribution, are more important factors rather than the surface area. At first, maximum porosity is considered as the most important property of the catalysts, if proper porosity is not achieved, the chemical composition of the active metal is not important, and it is important to maintain the catalyst life time. In this research, the influence of different additives such as, poly ethylene glycol (low density), ammonia (in different concentrations), ammonium carbonate, poly vinyl alcohol, hexamine, and methanol on the textural properties of the catalyst which is made of boehmite powder of Azarshahr Nephlinsinite mine ores are investigated. In this regard, and in order to prove the different additives influence on the properties of the catalyst within these experiments, different characterization laboratory method and apparatuses have been used, such as X-ray diffraction (XRD), N2-adsorption/desorption, and radial strength techniques. As a result of all aforementioned experiments and characterization tests, it is shown that, the best additive is ammonia (10%), and catalyst properties which is prepared by ammonia (10%) as an additive is too similar to the commercial sample properties.