refining india 2023
Rajeev Kumar, Ravi Kumar Voolapalli, Pranab Kumar Rakshit and Aniruddha Kulkarni Corporate R&D Centre, Bharat Petroleum Corporation Ltd K Model: The future of b lending
The PEM electrolyser in the Petro-SIM process simulator is shown in Figure 1 .
Understanding Voltage Calculations Voltage calculations provide a solid foun- dation for understanding the energy requirements and feasibility of electrol- ysis at standard conditions (25°C and 1 atm) and at different pressure or temper- ature values. As seen in Figure 2 , voltage calculations are a crucial aspect of elec- trolysis to determine the process’s effi- ciency and feasibility. These calculations include: • Electrolysis that requires a minimum supply of electric energy, represented by the reversible voltage from the estimated Gibbs free energy of formation of water:
In a refinery operation, the profitability margin is increased when heavy crude fractions are blended with light crude without affecting processability. However, heavy oils with high asphaltene content can cause issues with the desalter oper- ation, such as the formation of strong water emulsions with asphaltene, foul- ing in heat exchangers, and coking dur- ing processing. These issues can lead to excess fuel firing and loss of the advan- tages of purchasing heavy crudes. Thus, accurate prediction of crude compatibility can be a robust tool for refinery operators to use before starting any process. Current benchmark processes to deter- mine the compatibility of crude oils are done experimentally and take at least a few weeks to complete. Existing lab tests are limited to checking the compatibility of only two crude oil blends at a time. To check three or more crude oils, they need to test the compatibility of the first two and then mix the two with the third and subsequent ones, which is an exhaustive and time-consuming process. K Model is a quick and accurate method for crude oil blend compatibility and opti- misation. It was developed by coeffi- cients obtained from regression analysis between the ratios of physical parame- ters in known crude oils and composite compatibility measures determined from multiple compatibility test results on the known crude oils. Several compatibil- ity tests are used in the process, includ- ing colloidal instability index (CII), colloidal stability index (CSI), Stankiewicz plot (SP), qualitative-quantitative analysis (QQA), stability cross plot (SCP), Heithaus param- eter (or parameter P), Heptane Dilution (HD), toluene equivalence (TE), spot test, and oil compatibility model (OCM). K Model requires only a few physical parameters of the crude oil as input for optimisation, such as sulphur, carbon res- idue, API, and kinematic viscosity. A web-based version of K Model has been developed, which runs over the internet and predicts results rapidly. This enables the user to arrive at an optimum
• The maximum natural amount of energy for electrolysis that corresponds to the thermo-neutral voltage calculated from the heat of formation of water:
Using thermodynamic models, advanced process simulators determine precise esti- mates of reversible and thermostable volt- ages based on temperatures and pressures. System Analysis via Process Simulators Using digital twin electrolyser models, all system curves for voltage requirements and hydrogen production can be assessed, including the estimation of hydrogen cross- over, as shown in Figure 3 . Conclusion: Growing Need for Process Simulators The demand for computer tools that facil- itate engineering design, operations, optimisation and even for research and development is high. With careful planning and diligently applying advanced mathe- matical and engineering principles, opera- tors can achieve relatively low hydrogen production costs while capitalising on sub- stantial tax credits. According to the US Inflation Reduction Act,³ these tax cred- its can reach 3 USD/kg of hydrogen when the lifecycle of greenhouse gas emissions (GHG) emissions does not tip 0.45 kg of CO₂e/kg hydrogen. The water electrolyser unit operation marks a significant milestone. This new unit empowers operators to model many types of electrolysers. Users can build dig- ital twins for green hydrogen production processes for both design and operation. Finally, operation engineers can lever- age the digital twin to monitor the perfor- mance of the water electrolyser. References 1 Energy.gov (2023, June 30). U.S. National Clean Hydrogen Strategy and Roadmap. Retrieved September 21, 2023, from https:// www.hydrogen.energy.gov/clean-hydrogen- strategy-roadmap.html 2 india.gov.in (2023, March 6). National Green Hydrogen Mission. Retrieved September 21, 2023, from https://www.india.gov.in/spotlight/ national-green-hydrogen-mission 3 Van Nostrand, E., Feiveson, L. (2023, August 16). The Inflation Reduction Act and U.S. Business Investment. Retrieved September 21, 2023, from https://tinyurl.com/2fm8pjwx
potential is present for a given crude oil blend composition. Module 2B estimates the optimum blend composition of crude oils with bitumen potential. • Module 3 is for fuel oil blending, which gives the user a tool to optimise the cutter stock and minimise the cost of production for a fuel oil of certain desired specifica- tions. Overall, the software integrates a leading web-based blending solution with a user-friendly GUI. Refiners can use this product in several ways, such as feeding a healthy diet to the refinery to maintain equipment health, ensure smooth operation, save energy, and keep taking good care of the envi- ronment by reducing carbon footprint. K Model has the capability to significantly contribute to the world at large if refiner- ies adhere to minimising asphaltene pre- cipitation. With ‘K Model: Blending for future’, a new dimension is added to the entire oil sourcing process. The product is commercially available and currently live on www.bpcl.kmodel.in.
blend based on economics, availability, and processing feasibility in real-time. It promotes the simultaneous evaluation of multiple crude mix options in quick time and helps the user to make more informed decisions. The K Model soft- ware package offers different modules that provide a variety of options to meet refinery blending needs. It consists of three modules: • Module 1 is for crude oil blend compat- ibility and has two sub-modules. Module 1A predicts crude blend compatibility for known blend compositions. Module 1B predicts the optimal and compati- ble crude oil blend that can be achieved using a set of crude oils. K Model pro- vides the option for blend optimisation of up to 10 crude oils, considering different blending constraints such as blend com- patibility, viscosity, pour, acidity, nitro- gen, sulphur, overall distillate yield, and crude oil availability. • Module 2 is for identifying the bitu- men potential of blends. Like Module 1, Module 2 also has two sub-modules. Module 2A checks whether bitumen
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Figure 1 K Model offers three different modules that provide a variety of options to meet refinery blending needs
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