In this master’s thesis the hydrogen distribution network of the Porvoo refinery has been studied. Possible means to make it more effective and to reduce the amount of purged hydrogen to the fuel gas network have been considered. The study is based on the hydrogen balance followed by pinch analysis.

In the literature review, the process units of the refinery hydrogen distribution network have been presented and brief description of their operation principles has been given. The hydrogen pinch method details are presented including how to take into account the real process constraints while conducting it. It has been presented at the end of the literature review how to carry out the optimization of the hydrogen distribution network stepwise.

In the experimental part of the work a detailed flow diagram of the hydrogen distribution network was drafted yielding insight into the refinery hydrogen distribution. Simplified version the flow diagram was made and hydrogen balance was based on it. Hydrogen pinch analysis was performed from the hydrogen balance and significant hydrogen purge to the fuel gas network was detected.

In order to make hydrogen usage more efficient on the refinery, the fuel gas stream from the hydrogen sulfide recovery unit 2 should be minimized or utilized elsewhere. Also, the design values of molecular weights of the flow meters should be corrected to match the current operation mode. Monitoring plan for this corrective action should be developed. Also, the online hydrogen analyzers should be calibrated regularly and offline samples should be taken frequently enough from the hydrogen distribution network,

It should be noticed that minimizing the refinery hydrogen production is not always the most economical solution. In some cases increasing the hydrogen partial pressure in the reactor of the hydrogen consuming unit may increase the profitability of the unit more than the increased hydrogen production costs.