Rijeka, February 3, 2026 – Following the completion of construction of the new delayed coker unit and its associated infrastructure at Rijeka Refinery, as well as the conclusion of the cold commissioning phase using air, INA has entered a critical new stage – hot commissioning, that is, testing the facility with process fluids as a final verification of equipment functionality before the unit is brought online. This marks the final phase of the Rijeka Refinery Upgrade Project before the entire unit is put into trail operation, which is expected to commence in March.
Hot commissioning represents the stage where process fluids are gradually introduced into the system, which has previously undergone cold testing. Initially, auxiliary media such as steam, water, and fuel gas are used, followed by petroleum products, all under strictly controlled pressure, temperature, and safety conditions. During this phase, equipment functionality is verified under real operating conditions, automation and safety systems are checked for compliance, and process stability is ensured before trial operation in commercial mode begins. This phase is expected to last several weeks, after which the facility will enter trial operation and gradually ramp up to full operational readiness.
“By entering the hot commissioning phase, we have taken another significant step toward full commercial production at our new delayed coker unit. This is one of the most demanding stages in executing such a complex energy project, as it is the first time process fluids are introduced, and all technological and safety functions are tested under real conditions. Our priority is to carry out the entire procedure in a controlled, safe, and phased manner, in line with the highest industry standards. Upon successful completion of hot commissioning, we expect to launch trial operation of the unit, with the entire complex reaching full capacity during 2026,” stated Goran Pleše, Operating Director for Downstream at INA.
The Rijeka Refinery Upgrade Project, valued at nearly EUR 700 million, is the largest single investment in INA’s history and currently one of the most significant industrial projects in the Republic of Croatia. It encompasses the construction of the delayed coker unit (DCU), modernization of existing facilities, a new port, silos, a closed coke transport system, and a new transformer station – the largest in the country – which ensures reliable power supply for the new complex. Thanks to this project, the Rijeka Refinery complex is being transformed into one of the most technologically advanced facilities in the region, featuring higher energy efficiency, improved crude utilization, and a greater share of high-value products.
With the commissioning of the delayed coker unit, INA will significantly increase diesel production – by up to 30 percent – as well as other high-value distillates, while simultaneously reducing the need to import products, especially during the peak summer tourist season. The production process will eliminate the need to import vacuum gas oil (VGO), which is predominantly of Russian origin on the European market, thereby strengthening Croatia’s energy security and reducing dependence on imported raw materials. INA’s focus remains on safe and continuous supply to the Croatian market and key regional markets – Bosnia and Herzegovina, Montenegro, and Slovenia.
The Rijeka Refinery upgrade project is part of a long-term investment cycle in which INA and MOL Group have invested more than EUR 1 billion over the past decade in the modernization of refining and logistics infrastructure.
About INA Group
INA Group plays a leading role in the Croatian oil business and holds a significant position in the region in oil and gas exploration and production, oil refining, and distribution of oil and petroleum products. The company consists of several subsidiaries wholly or partially owned by INA, d.d. The Group is headquartered in Zagreb, Croatia. In the field of oil and gas exploration and production, INA currently operates in Croatia and Egypt. Oil refining takes place at the Rijeka Refinery, while the Sisak industrial site is being transformed into a hub for sustainable alternative activities. The regional retail network includes more than 500 service stations in Croatia and neighbouring countries. INA Group is a member of the MOL Group.
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