Transforming C 4 into high-octane gasoline
An innovative and sustainable solution for producing BS-VI-compliant regular and premium-grade gasoline
Prosenjit Maji, Pushkar Varshney, Talari Raju, Satyen Kumar Das, R K Kaushik Singha, and Alok Sharma Research & Development Centre, Indian Oil Corporation Limited
I n recent times, environmental regulations on fuel specifications have forced refiners to search for sustainable and greener technologies. Currently, Indian refineries are producing Bharat Stage (BS) VI-quality fuels as per the Auto Fuel Policy mandate effective from April 2020. Over the past 20 years, fuel specifications have become increasingly stringent, as evident from the reduction in sulphur content by 99.5% to 10 ppm in BS- VI. Additionally, the research octane number (RON) requirement has been enhanced by four units, from 87 to 91 for normal-grade gasoline and 95 for premium-grade gasoline in BS-VI. The aromatics and olefins contents have also reduced by more than 30% in the past 20 years, which has adversely impacted the RON. The requirement of meeting the sulphur levels indicated above in the overall gasoline pool while maintaining other parameters such as RON and motor octane number (MON), total aromatics, total olefins, and Reid vapour pressure (RVP), is quite challenging due to the associated RON loss on deep desulphurisation. More specifically, the production of premium- grade gasoline poses a significant challenge for refiners using existing refinery processes. Hence, some additional streams with high octane will be required to bridge the gap. Considering the above, IOCL R&D has developed the Octamax process for the conversion of Cā streams from the catalytic cracker and/or naphtha cracker to produce a high-octane stream (blending RON [BRON] >110), which can be directly blended into a gasoline pool. Figure 1 shows the typical
C stream
Ole nic LPG from
Unconverted C to LPG
C /C splitter
c atalytic/ na phtha c racker
Octamax Unit
C stream
block diagram for an Octamax unit. Owing to its high BRON, it provides refiners with significant flexibility in meeting stringent gasoline specifications and enables an increase in gasoline production by blending low-octane naphtha. Product to gasoline blending (RON >110) Figure 1 Typical block diagram of an Octamax unit With the rollout of E20 gasoline across India, the demand for higher base gasoline octane has become more critical, as the blended fuel must meet a minimum RON of 95. In this context, Octamax presents a strategic advantage. Unlike traditional octane boosters, such as MTBE or ethanol, which contribute to the overall oxygen content of gasoline, the Octamax product is a for refiners using existing refinery processes. Additional streams with high octane will be required to bridge the gap ā ā Production of premium-grade gasoline poses a significant challenge
Refining India
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