End-to-end digital enablement of petcoke gasification complex By leveraging digital tools, an Indian refinery has improved plant reliability, optimised strategies, reduced energy losses, and enhanced decision-making
Saswat Panda and Vijay Sastri Reliance Industries Limited
J amnagar Refinery Complex operates the world’s largest refinery along with an integrated petcoke gasification (PCG) and cracker complex. The entire site is seamlessly interconnected with power, steam, hydrogen, and fuel systems, ensuring maximum efficiency and reliability. The PCG complex utilises petroleum coke, commonly known as petcoke, which is the heavy, carbon-rich residue obtained from the bottom of the refinery barrel. This petcoke is processed into a pumpable slurry to enable smooth feeding into the gasification system. The slurry preparation involves milling the petcoke to a fine particle size and subsequently mixing it with water to achieve the desired viscosity and flow characteristics. Once prepared, the slurry is pressurised and pumped directly into the gasifier. The petcoke particles undergo partial oxidation in the presence of high-purity oxygen supplied from an air separation unit. The reaction occurs at extremely high temperatures, ~1,500°C, creating a highly reducing environment. Under these conditions, the carbon in petcoke reacts with oxygen and steam to form synthesis gas (syngas), a mixture primarily consisting of carbon monoxide (CO) and hydrogen (H₂). The raw syngas exiting the gasifier contains several impurities, including hydrogen sulphide (H2S), carbon dioxide (CO₂), particulates, and trace components. These impurities are removed in a dedicated downstream purification system known as the acid gas recovery (AGR) unit. The AGR unit selectively absorbs H2S and CO₂, ensuring that the syngas is thoroughly
cleaned to meet downstream process specifications. The result is high-purity, clean syngas, suitable for further applications, such as hydrogen production, power generation, or chemical synthesis. The sulphur-bearing stream captured in the AGR unit, mainly H2S, is routed to the sulphur recovery unit (SRU). In the SRU, H2S is converted into elemental sulphur via the Claus process and subsequent tail gas treatment steps. The recovered sulphur is then cooled, solidified, and made available for external sale, contributing to both revenue generation and environmentally responsible handling of refinery byproducts. This integrated sequence, from petcoke slurry preparation and gasification to impurity removal and sulphur recovery, enables efficient utilisation of refinery residue while producing valuable syngas and commercial-grade sulphur, thereby enhancing overall resource efficiency and minimising waste. Clean syngas is utilised for: Power and steam generation : Clean syngas is used as fuel to generate power and steam. Hydrogen production : A portion of syngas is processed in the CO shift unit to produce raw hydrogen, which is further processed to produce 99.9% clean hydrogen for consumption in the refinery. Substituted natural gas (SNG) : Syngas is converted to SNG in the methanation unit, serving as additional fuel gas. The PCG complex plays a pivotal role in supporting the overall energy and hydrogen ecosystem of the Jamnagar Refining Complex (see Figure 1 ). The PCG complex currently
Refining India
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