blanketing pressure controllers, the consumption of nitro- gen can be minimised. Flow through utility station of nitrogen Different approaches for determining the normal and peak demand for refiners exist, and the determination of overall normal and peak demand is considered beyond the scope of this article. Nonetheless, it is observed across refiners that for both normal and peak nitrogen demand, the nitro- gen flow through at least one utility station is considered. The nitrogen flow through a utility station is typically seen to range from 200 Nm 3 /h to 400 Nm 3/h. It was observed that when considering compressible flow through a 0.75in pipe, the nitrogen flow rate is 350 Nm³/h where upstream nitrogen pressure is at 8 barg and downstream at atmos - pheric pressure. Utility station sizes very often are 1in. Key takeaway: The designer should consider the maximum possible nitrogen flow through a utility station while esti - mating normal and peak nitrogen demand. Conclusion This article emphasises key considerations for nitrogen management in refinery operations at the design stage, focusing on nitrogen blanketing in surge drums and tank- age. The findings reveal that conventional guidelines, notably those based on API 2000 standards, may lead to overestimation of nitrogen requirements. Such overestima - tion not only elevates nitrogen demand but also contributes to operational inefficiency and waste.
Beyond the scope of tank and surge drum blanketing, the articles outlines crucial best practices for handling nitrogen throughout various units in a refinery. This encompasses optimal purging protocols, sizing of nitrogen lines for HP hydroprocessing units, actual peak nitrogen flow through the utility station, necessity of nitrogen connection for the LP section of hydroprocessing units, and effective control mechanisms for gas blanketing. In summary, this article endorses a customised approach to managing nitrogen, considering actual operational scenarios. It suggests a balanced use of both standard and alternative methods without compromising safety. Implementing these recommendations has the potential to result in significant cost reductions, more efficient resource allocation, and the upholding of stringent safety norms.
Appendices 1 and 2 can be viewed in the digital issue.
Rajib Talukder is a Process Specialist in the Global Manufacturing Excellence department at Aramco, Saudi Arabia. He has more than 30 years of experience in process engineering and holds a B.Tech in chemical engineering from NIT Tiruchirappalli, India. Email: rajib.talukder@aramco.com Prabhas K Mandal is an Operations Engineer Specialist at Aramco. He has more than 30 years of experience in petroleum refining, and supports front end design development for capital projects. He holds a B.Tech in chemical engineering and a M.Tech in petroleum engineering. Email: prabhas.mandal@aramco.com
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