Feedstock optimisation A refiner requested co-processing of an indigenous crude along with an imported crude mix for design purposes. However, these crudes had very dif- ferent paraffin and aromatic content, which may have caused crude compatibility issues and could lead to asphal- tene precipitation in crude pipelines and furnaces. The Petro-SIM digital twin was used to determine the maxi- mum amount of indigenous crude that could be safely co- processed with imported crude blends. Furthermore, the overall crude blend was optimised, resulting in additional benefits of about USD 0.6 per bbl. Improved feed definition A process digital twin helps predict rigorous and accurate intermediate stream proper- ties based on the crude assay data and provides improved feed quality predictions for the conversion and treatment unit. A unit process digital twin was used to predict the vacuum gas oil (VGO) hydrotreater feed quality, consid- ering deep cut VGO. The LP model predicted very con- servative responses to feed distillation change in terms of key feed qualities (e.g., nitrogen, metals, and Conradson Carbon [CCR]), which would have caused catalyst life design issues. The model prediction helped design the right catalyst volume and reactor LHSV to process diffi- cult feed. Refinery-petrochemical value maximisation The margin improvement studies revealed an opportunity to process kerosene as feed to the steam cracker to produce higher petrochemical products instead of blending it with diesel, resulting in an overall improvement of nearly USD 1 per bbl. Proper design considerations were taken at the design stage to process kerosene in the steam cracker. KBC high- lighted key challenges and their mitigations to process ker- osene feed to steam crackers, which included the addition of impurities removal systems and increasing the capacities of heavier end processing. Gasoline blend feasibility A process digital twin was used in the feasibility stage to identify the infeasibility of the gasoline blend. This was primarily due to higher aromatic quantities from certain gasoline blend streams, which were improperly captured in the LP model. Further, the model was used to evaluate the maximum gasoline that could be made with the available streams. Furthermore, additional facilities were considered in the design to address the requirement for the imported blendstock to meet the full gasoline target as per the required specifications. Steam and power system optimisation Originally, pro- posed power plant configurations included power genera- tion through several condensing steam turbine generators (STGs). Similarly, there were condensing turbines consid- ered for critical drives in process plants. Our SMEs reviewed the overall system and proposed using a more efficient motor drive. In addition, the whole steam and power gen- eration system was optimised using the energy digital twin, resulting in significant energy, Capex, and operating cost savings.
Complex turnaround optimisation Our SMEs evaluated the proposed turnaround philosophy considering all appli- cable scenarios and optimised it based on global bench- marks and best practices. This resulted in eliminating and reducing the sizes of several tanks that were part of the original philosophy. Consequently, Capex was reduced by nearly 3% of the total project cost. Conclusion A refinery and petrochemical integrated project requires substantial capital investment. Once completed, they face several challenges such as fluctuating feedstock and product prices, as well as regulatory and environmen- tal changes. All these uncertainties make it necessary for projects to be completed within the planned budget and schedule. The traditional approach and tools used during the early stages of these projects must be revisited because of the ever-increasing scale and complexity of these inte- grated refinery-petrochemical complexes. The OTA brings an independent perspective and global experience from working on similar technologies and proj- ects worldwide. Helping owners set global- and unit-level objectives ensures all key stakeholders are aligned with project goals. It is important that the OTA deploys a meth- odology combining subject matter expertise with rigorous tools to validate assumptions. Such a methodology is essential to minimise the risks of design changes at later stages of the project. By using process digital twins during the design stage, optimisation opportunities and critical constraints can be identified and modified accordingly. Additionally, the OTA can mitigate any skill gaps within the owner’s team while enhancing capability via training and sharing process knowledge and best practices. As an OTA during licensor selection and design review, KBC has improved profitability and reduced capital cost across the entire lifecycle of refineries and petrochemi- cal complexes. Lastly, its proprietary Profit Improvement Program optimises the yield and energy of operating facili- ties. Combining this experience with robust technology and tools can help owners achieve these goals. Amit Sarna is a Principal Consultant with KBC Advanced Technologies Private ltd, heading the KBC India operations and supporting the con- sulting business line in KBC. He has more than 27 years of global experience in areas of feasibility and configuration studies, refinery petrochemical integration, profit improvement projects, revamp and asset optimisation studies. He holds a bachelor’s degree in chemical engineering from Indian Institute of Technology B.H.U. Email: amit.sarna@kbc.global Sachin Srivastava is a Senior Consultant at KBC and is involved with KBC’s consulting practice. He has more than 13 years of experi- ence as an ethylene technology specialist across functions including operations, technical services, and capital project support. He holds a bachelor’s degree in chemical engineering from Indian Institute of Technology, Kanpur. Email: sachin.srivastava@kbc.global
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PTQ Q4 2022
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