Hydrocracking: Handling of instrument air failure – should 0.7 bar be used for startup?

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Our plant has newly installed a hydrocracking unit with a full reflux configuration; hydrogen mixing is carried out before the furnace. I am currently working on an emergency response plan. Having referred to many manufacturers, I found that in the event of a loss of instrument air, it is necessary to immediately activate the 0.7 bar system. I am considering shutting down the fresh hydrogen compressor after the loss of instrument air, while keeping the circulation compressor operational, and handling the situation by stopping feedstock supply and turning off the furnace while leaving a small amount of flame alive. Since the hydrogen mixing valve and the cold hydrogen valve are both fully open, this should prevent the furnace temperature from rising excessively. Additionally, a short-cycle distillation process can be used, which would allow us to avoid activating the 0.7 bar system. In another scenario, if the furnace bed temperature rises too high, then the 0.7 bar system would need to be activated. I’m not sure if this approach is acceptable. I’ve referred to the practices of hydrocracking units at Dalian Petrochemical, Changqing, Dushanzi, Jinxi, Yanshan, Fushun, and other sites, all of which suggest activating the 0.7 bar system first in case of a loss of instrument air. I’m not understanding this, and I hope to get some clarification