Delayed coking process with pre-cracking reactor
AssigneeIndian Oil Corporation Limited
InventorsSatyen Kumar Das, Ponoly Ramachandran Pradeep, Terapalli Hari Venkata Devi Prasad, Arjun Kumar Kottakuna, Madhusudan Sau, Debasis Bhattacharyya, Sanjiv Kumar Mazumdar, Sankara Sri Venkata Ramakumar
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Abstract
The present invention relates to delayed coking of heavy petroleum residue producing petroleum coke and lighter hydrocarbon products. The invented process utilize a pre-cracking reactor and a reactor furnace for mild thermal cracking of the feedstock and an intermediate separator, before being subjected to higher severity thermal cracking treatment in a coker furnace and a coking drums, resulting in reduction in overall coke yield.
Claims2
A method of reducing overall coke yield said method consisting of the steps of:
- (a) heating a hydrocarbon feedstock (40) in a reactor furnace (41) to obtain a hot feed (42);
- (b) introducing the hot feed (42) of step (a) in a pre-cracking reactor (43) wherein it undergoes mild thermal cracking reactions at a pressure in the range of 1 to 15 kg/cm2 and a residence time in the range of 1 to 40 minutes to obtain an outlet product material stream (44);
- wherein the pre-cracking reactor is a plug flow reactor;
- wherein the pre-cracking reactor is operated at a temperature range of 370 to 470° C.;
- (c) passing the outlet product material stream (44) of step (b) an intermediate separator (45) to split the outlet product material stream (44) into top fraction (46) and heavy bottom product (47) and transferring the top fraction (46) to a main fractionator (53);
- wherein the intermediate separator (45) is operated in the pressure range of 0.2 to 10 Kg/cm2;
- (d) heating the heavy bottom product (47) of step (c) in a coker furnace (49) to obtain a hot hydrocarbon stream (50);
- wherein the heavy bottom product (47) is mixed with a Clarified Oil (CLO) stream (48) prior to heating in the coker furnace (49);
- (e) transferring the hot hydrocarbon stream (50) of step (d) to preheated coke drums (51) where it undergoes severe thermal cracking reactions at a temperature in the range of 470 to 520° C., a pressure in the range of 0.5 to 5 kg/cm2 and a residence time of more than 10 hours to obtain product vapors (52);
- and
- (f) passing the product vapors (52) of step (e) to the main fractionator (53) to obtain desired product fractions (54, 55, 56, 57, 58);
- wherein the hydrocarbon feedstock (40) of step a) is obtained by feeding a resid feed (39) selected from vacuum residue, atmospheric residue, deasphalted pitch, shale oil, coal tar, heavy waxy distillates, foots oil, slop oil or blends thereof, into a bottom section of the main fractionator (53) and obtained as a bottom fraction from the main fractionator (53), prior to heating in the reactor furnace, wherein the resid feed (39) is introduced into the bottom section of the main fractionator (53) below a location where the top fraction (46) and the product vapors (52) enter the main fractionator (53);
- wherein the hydrocarbon feedstock of step a) has conradson carbon residue content of above 4 wt % and density of at least 0.95 g/cc.
Dependencies are inferred from the claim text.