Process for producing low-carbon olefins by gaseous phase catalytic cracking of heavy oil with multi-stages in milliseconds

A process for producing low-carbon olefins by gaseous phase catalytic cracking of heavy oil with multi-stages in milliseconds, wherein:

• 1) a high-efficiency atomizing nozzle sprays the heavy oil preheated to 150° C.-350° C. from a feed inlet of a downflow modification reaction tube into an upper portion of the downflow modification reaction tube, the produced oil mist is mixed with a high temperature solid heat carrier at a temperature ranging from 650° C.-1,200° C. flowing downward from a first return controller for milliseconds, so as to heat, vaporize and pyrolyze the oil mist and obtain an oil and gas and a solid heat carrier to be regenerated, the pyrolysis reaction temperature is within a range of 480° C.-850° C.;
• 2) the oil and gas as well as the solid heat carrier to be regenerated flow rapidly and downward to a first rapid gas-solid separator at the bottom of the downflow modification reaction tube to carry out a gas-solid separation to obtain a coked solid heat carrier to be regenerated and a high temperature oil and gas;
• 3-1) the coked solid heat carrier to be regenerated flows through a first flow controller and enters into a lower portion of a modification regeneration reactor to conduct a regeneration reaction with a regeneration agent, the temperature of the regeneration reaction is within a range of 680° C.-1,250° C.;
• then the regeneration gas and high temperature solid heat carrier produced by the regeneration reaction are subject to a gas-solid separation in a first gas-solid separator on top of the modification regeneration reactor, then the high temperature solid heat carrier with a carrier/oil ratio of 1-14 passes through the first return controller and flows into a top of the downflow modification reaction tube and enter into the downflow modification reaction tube so as to participate in circulation and cracking of the heavy oil;
• the regeneration gas from the first gas-solid separator is subject to heat exchange and then output;
• 3-2) the high temperature oil and gas from the first rapid gas-solid separator is not condensed but directly flowing in the gaseous phase into a millisecond cracking reactor and mixing with a regeneration cracking catalyst having a temperature of 600° C.-850° C. to carry out a gas phase catalytic cracking reaction, the cracking reaction temperature is within a range of 530° C.-750° C., then a cracking oil and gas and a cracking catalyst to be regenerated produced by the cracking reaction are subject to gas-solid separation in milliseconds;
• 4-1) the cracking catalyst to be regenerated flows through a second flow controller and enters a lower portion of the crack regeneration reactor and performs a regeneration reaction with air, the temperature of the regeneration reaction is 630° C.-900° C., a flue gas and a high temperature crack catalyst produced by the regeneration reaction are subject to a gas-solid separation in a second gas-solid separator at the top of the crack regeneration reactor;
• the high temperature crack catalyst with a catalyst/oil ratio of 1-8 passes through a second return controller and flows into the millisecond cracking reactor to participate the circulation reaction, and the flue gas is subject to heat exchange and then output;
• 4-2) the cracking oil and gas produced by the cracking reaction enter into the subsequent separation devices to separate out the low carbon olefins and aromatic hydrocarbons.