What are the Pros & Cons in case of Hot start-up of Hydrogen generation unit? Why it is generally not preferred and also why is there no detailed procedure given in operating manual ?
Rajesh Nandanwar, Bharat Oman Refineries Limited, Bina, email@example.com
Refiners prefer hot start up as you can be again online within short time as compared to cold start up where you would be cooling the plant and then again heating it up to desired temprature before feed in. As such hot start up are good if you are able to monitor all the critical parameters like firing pattern, steam flow to tubes, burner distribution, tube skin temperature and feed preheating before introduction of feed. Most critical parameter is the time lag between actions and the response. Like you have started increasing firing but response would take 15 minutes to indicate on cross over and reformer outlet temperature.
All this requires in depth experience and licensor considers this as risk as localized overheating in some part of furnace could lead to damage to catalyst and even reformer tubes.
It is always recommended to go with normal start up as the conceqences of one uncontrolled parameter on overall plant is very high and could risk plant and equipment life.