Two stage thermal cracking process with multistage separation system

A method of reducing overall coke yield in a delayed coking process, said method comprising the steps of:

• a) passing a fresh hydrocarbon feed to a bottom of a main fractionator and mixing with internal recycle to make a secondary hydrocarbon feedstock;
• b) heating the secondary hydrocarbon feedstock in a furnace to obtain hot feed at a desired inlet temperature of a pre-cracking reactor;
• c) passing the hot feed at the desired inlet temperature and a pressure to the pre-cracking reactor, wherein the hot feed undergoes mild thermal cracking reactions to obtain an outlet product material stream;
• d) introducing the outlet product material stream to a first intermediate separator to split hydrocarbons in the outlet material stream into a first top product and bottom fractions, wherein the first top product comprises lighter products and gases and the bottom fractions is split into a first portion and a second portion;
• e) routing the first top product to the main fractionator;
• f) separating a first portion of the bottom fractions in a second intermediate separator column operating at vacuum conditions to obtain a second top product and a heavier bottom product;
• g) passing the second top product obtained in step (f) to the main fractionator;
• h) withdrawing the heavier bottom product from the second intermediate separator column of step (f) and passing to the main fractionator, wherein the heavier bottom product comprises Light Vacuum Gas Oil (LVGO) and Heavy Vacuum Gas Oil (HVGO);
• i) mixing the second portion from the first intermediate separator of step (d) and the heavier bottom product from the second intermediate separator column of step (f) and heating in a furnace to a desired coking temperature to obtain a hot hydrocarbon stream;
• j) passing the hot hydrocarbon stream from the furnace to a preheated coke drum;
• and
• k) passing product vapors exiting the coke drum to the main fractionator column to obtain product fractions.