Abstract: A fluidized catalytic conversion method for maximizing the production of propylene includes the steps of: 1) contacting a heavy feedstock oil with a catalytic conversion catalyst having a temperature of 650° C. or higher for reaction; 2) contacting a hydrocarbon oil feedstock having an olefin content of 50 wt % or more with the catalytic conversion catalyst after the reaction of step 1); 3) separating a first catalytic cracking distillate oil and a second catalytic cracking distillate oil from the resulting reaction products; 4) separating an olefin-rich stream from the first catalytic cracking distillate oil; and 5) recycling the olefin-rich stream. The method can effectively improve the yield of propylene and realize an effective utilization of petroleum resources.

Abstract: A fluidized catalytic conversion method for producing light olefins includes the following steps: 1) introducing an olefin-rich feedstock into a fluidized catalytic conversion reactor, and contacting with a catalyst having a temperature of 650° C. or higher for reaction; 2) separating the reaction product vapor obtained by the reaction to obtain a stream comprising C5+ olefins; and 3) recycling at least a part of the stream comprising C5+ olefins to step 1) for further reaction. The fluidized catalytic conversion method can effectively improve the yield of light olefins, improve the selectivity and improve the ethylene/propylene ratio of the product.

Abstract: The application discloses an improved wheel pretreatment rack. The wheel pretreatment rack includes a hook, tripods, positioning slide blocks, positioning holes, a main rod, bearing rods, braces and positioning clamping jaws. Compared with the traditional wheel pretreatment rack, the improved wheel pretreatment rack in use has the advantages that the requirement of wheels having different sizes for the pretreatment rack is met by adjusting the positions of the bearing rods up and down, and the problems of drop, scratch and the like in the cleaning pretreatment process of the wheel may be effectively prevented by a wheel three-point-fixing mode.

Abstract: The application discloses an improved wheel pretreatment rack. The wheel pretreatment rack includes a hook, tripods, positioning slide blocks, positioning holes, a main rod, bearing rods, braces and positioning clamping jaws. Compared with the traditional wheel pretreatment rack, the improved wheel pretreatment rack in use has the advantages that the requirement of wheels having different sizes for the pretreatment rack is met by adjusting the positions of the bearing rods up and down, and the problems of drop, scratch and the like in the cleaning pretreatment process of the wheel may be effectively prevented by a wheel three-point-fixing mode.