... are different, the user can select the product by their sizes, pores and porosity, or if necessary ... molybdenum, nickel and cobalt or other active components to prevent the catalyst from coking or poisoning.Technical ... are divided into 12 grades by reference to Al2O3 content varied from 25% to 95%,and every more 5 ... % constitutes a grade, but 12 sizes by reference to the diameter, such as Φ3 ,Φ6 ,Φ8 ...