Abstract: A cracking reaction device includes a preheating section, a lightening section, a reduced-pressure gasification section and a cracking section that are connected sequentially. A method for producing olefins by cracking involves pressurizing a cracking feedstock and water; subjecting the pressurized cracking feedstock and water to a first heating; subjecting the first heated cracking feedstock and water to a second heating and lightening the cracking feedstock in the presence of water to obtain a lightened mixture; gasifying the lightened mixture under a reduced pressure and subjected to a third heating to obtain a third heated mixture; and cracking the third heated mixture at a cracking temperature in the presence of steam to obtain a cracked product containing olefins.

Abstract: A method for cracking crude oil includes delivering the crude oil to a first tube group of a convection section of a cracking furnace for preheating and then performing vaporization to obtain a first gas phase and a first liquid phase; performing high-pressure extraction on the first liquid phase to obtain a non-asphalt oil and an asphalt; and mixing the first gas phase and the non-asphalt oil with water vapor respectively, or mixing the first gas phase with the non-asphalt oil prior to mixing with water vapor, then delivering the same to a second tube group of the convection section of the cracking furnace for heating, followed by delivering same to a radiation section of the cracking furnace for cracking to obtain a cracked product, and separating the cracked product to obtain low-carbon olefins.