Part V - Maximizing Realization of Petrochemicals from Integrated Complexes

Continuing from where we dropped vision of petrochemicals forming a central part of Hydrocarbon Industry, perhaps the subject can be dwelt a bit further to outline what has been outlined in several case studies in the book. The essence of all the studies has always been value addition to exploit the last molecule for valorization.

In this context, the discussions have centered between vacuum residue bottoms being upgraded through delayed coking vs residue hydro cracking. This has been a raging subject of debate and discussion in the Indian Context, ever since the slurry hydro raking technology has matured and gained commercial experience. An overview in perspective of what is dealt expansively in the book is worth dwelling upon:

1. Most of the Refineries in the period 2004 through 2016-17 had a favorable bias towards the Delayed Coking Unit ( DCU) vis-a-vis Slurry Hydrocracking ( SHCU). The reason was predominantly the fact that, DCU offered a very competitive bottoms upgradation solution. Also the SHCU was not as pronounced a Technology until then, and was deemed expensive both as part of the SHCU facility itself, besides an added cost of significant quantum of Hydrogen requirement.

2. Towards 2016-17 the subject began to come under focus as the DCU was recognized as not so environment friendly, besides with the maturity of SHCU the overall distillate requirement at the Refinery level was deemed to enhance between 4 to 6 % as the typical 30% coke from DCU could be valorized to the extent that the reject pitch from SHCU could range between 6-8%. This offered a significant value addition opportunity.

3. Unless the coke from DCU could be valorized , it would always be a challenge to dispose it, due to its low ash content but high quantum of sulfur. Gasification as a blend with coal was a solution, but that had its own concerns as has been pointed out by some of the readers in Part IV interjections. SHCU on the contrary had the advantage of 92% plus conversions, thereby the reject pitch was the only waste disposition issue. One of the acceptable way of the pitch disposal could be in road building or brick led infrastructure initiatives.

4. Since in the emerging times , Petrochemicals has been a strong initiative towards integrated complexes the light end produced from the SHCU in terms of LPG, Naphtha, Kerosene all could be well established dedicated feedstocks to the olefin complexes thereby providing a distinct bias towards Petrochemicals as gasoline and Diesel could be rationalized.

5. SHCU could provide additional integration facilities by allowing the Hydrotreated heavier VGO produced from the unit to be routed to a Petro FCC for further enhancement of Propylene production. The Ethylene from the PFCCU off gases could also be recovered in the Olefin Cryogenic sections. The Propane recovered from PFCCU could also be cracked in the olefin complex.

6. Possibility of a combined Once through Hydrocracker OHCU in the complex based on the VGO from the VDU as well as from the SHCU on 60-70% conversion could be considered to produce unconverted bottoms from OHCU as feeds to PFCCU can be considered for maximization of Petroproducts and Gasoline as may be required from the Integrated complex.

7. To add muscle to the configuration and maximization of petrochemicals the heavier variety of Kerosene from the Straight run facility as well as from the OHCU can be utilized to produce Linear Alkyl Benzene, LAB to support a world scale plant. This will optimize the ATF production from the complex, besides adding to the petrochemicals kitty.

8. Since the complex Bias in the newer complexes could be towards the maximization of petrochemicals, the Heavy naphtha could be reformed to recover Benzene, Toluene and Xylenes- BTX from the complex. The Bottoms of the Olefin complex could be combined with the BTX from the Reformer to support a world scale PTA complex while isomerizing toluene to xylene while captively consuming the Benzene in the LAB complex.

9. With all the building blocks effectively created in the complex Ethylene, Propylene could be converted to Polymers, MEG, Acrylates while PTA, LAB could be additional petrochemical produced from the complex. A natural addition to the complex could be a PVC complex, as Ethylene would be captively available while chlorine could be recovered through electrolysis of brine.

10. To provide a reduced carbon foot print , Green Hydrogen integration to the complex, with e-Cracking Furnaces in the Olefin complex and renewable fired Refinery, Reformer heaters could be considered. Tail gas to Ethanol, possibilities of Co2 capture for promoting Green Urea production could be considered for an Environment Friendly Integrated complex.

The Book is full of significant practical studies on the above lines which could be an interesting reading as several existing complexes in the country have been integrated in to evolve practical and realistic solutions!