Oct-2022

Indigenous technologies pave the way for crude oil-to-chemicals transition

The crude oil-to-chemicals (COTC) transition is being brought in due to growth in petrochemicals, estimated at 1.4 times GDP, which could contribute to a 35-40% increase in total oil demand worldwide.

Sarvesh Kumar, Madhusudan Sau and SSV Ramakumar
IndianOil Corporation Limited

Article Summary

Traditional refining generates 20% resid, with the major part as fuels, while 5-6% is converted to chemicals. A multi-prong approach targeting the chemical conversion of each fraction of crude oil is required to achieve the highest yields of light olefins and aromatic chemicals from crude oil. The refining and petrochemical industry can benefit immensely by adopting indigenous refining technologies developed by the IndianOil R&D Centre to achieve maximum COTC conversions.

IndianOil has developed a series of state-of-the-art technologies, such as INDMAX, INDALIN, indLPet, indResidH, Delayed Coker, and Ind-CokerAT, a combination of which can achieve higher crude to chemical conversions. The technology features are described below:

• INDMAX is a flagship technology from IndianOil and globally licensed jointly by IOCL and Lummus. This catalytic cracker technology enables the conversion of residue and gasoils to light olefins with selective catalyst and hardware technology. The technology can produce ethylene and propylene in the range of 3-5 wt% and 15-20 wt%, depending on the feedstock. The technology has been licensed to nine refineries in India and abroad. Three units are operating at different IOCL refineries.

• INDALIN is a catalytic cracking technology suitable for upgrading mainly cracked naphtha to light olefins and BTX with shape-selective catalyst and hardware employing a circulating fluidised bed reactor-regenerator configuration. This technology can also handle kero, SRGO, and straight-run naphtha, with high conversions and without any feed pre-treatment. The technology produces propylene in the range of 15-20 wt% on a fresh feed  basis with a P/E ratio of ~2, depending on the type of feed. Gasoline with a BTX content of up to 40 wt% is produced, which is a suitable feedstock for the aromatic complex.

• indResidH is an indigenous slurry hydrocracking technology for residue upgrading using a proprietary oil-soluble catalyst system. The process upgrades bottom-of-the-barrel (vacuum residue) to middle and lighter distillates using a slurry reactor system under high temperature and hydrogen partial pressure. The overall conversion of the process is between 94 and 96 wt%, and the middle distillate yield is around 55-65 wt%. For COTC purposes, the process parameters can be adjusted to improve naphtha yield, and middle distillate can be routed to a middle distillate hydrocracker to improve petrochemical intensity.

• Delayed Coker technology is indigenously developed and licensed by IndianOil jointly with EIL. The technology has been licensed to two coker units in the IOCL refinery, one of which is currently under operation and producing anode-grade coke. Also, a non-IOCL refinery has selected the technology to revamp their coker unit for processing one of the heaviest feedstocks (CCR ~30 wt%) among the delayed coker units (DCU) in India.

• Ind-CokerAT technology has been developed to improve the distillate yield by reducing the lower value coke by 4-5 wt% over conventional DCUs. This patented technology is a key solution to addressing the issue of petcoke disposal.

• indLPet is a mild hydrocracking technology which operates in the pressure range between 40 and 60 barg for highly aromatic FCC LCO conversion with a proprietary ring-opening catalyst system to BTX and BTX precursor (C₉-alkyl benzenes). The technology produces LPG (4-6 wt%) light naphtha (20-25 wt%), which can be routed to a naphtha cracker unit, heart-cut naphtha (55-65 wt%), rich in BTX, and BTX precursor, which can be directly routed to the aromatic complex, and ultra-low sulphur diesel (ULSD) (8-15 wt%). The sulphur and nitrogen in indLPet heart-cut are below <0.5 ppmw. The RON of total naphtha (light + heart-cut) is around 94-95 units and can be routed to the gasoline pool as an alternative. The technology is available in once-through and recycle configurations.

A synergistic combination of the above IOCL technologies can achieve maximum conversion of crude oil to value-added chemicals in the range of 55 to 65 wt%. One typical configuration developed by IOCL is shown in Figure 2, wherein crude oil is fed to the atmospheric vacuum unit (AVU) to obtain naphtha, gasoils, VGO, and vacuum residue. The straight-run naphtha with cracked naphtha from other units is fed to the INDALIN and steam cracker unit in the desired proportion for conversion to light olefins and aromatics. After hydrotreatment, VGO and indResidH gasoil are routed to INDMAX for further conversion to lighter products, including light olefins. INDMAX HCN and LCO are routed to indLPet to obtain light naphtha and aromatic-rich heavy naphtha for the aromatic complex and low-sulphur diesel as fuel. Vacuum residue is processed in the indResidH unit to obtain gases, light naphtha, gasoils, and pitch. Pitch and CLO are routed to the DCU/Ind-CokerAT unit for conversion to cracked naphtha and gasoil feed for INDALIN and premium quality anode-grade coke.

This short article appeared in the 2022 Refining India Newspaper, which you can view HERE