Croatian oil company INA has entered a decisive stage of its largest-ever industrial investment by launching live-process testing at the new heavy residue processing unit at the Rijeka oil refinery. This phase involves running the facility with process fluids as the final functional check before full commissioning, while trial operation of the entire complex is planned for March 2026.
The step follows earlier cold testing and includes the gradual introduction of steam, water and fuel gas, followed by petroleum products. All systems are being observed under strictly controlled pressure, temperature and safety conditions to verify process stability, the performance of automation and protection systems, and the reliability of equipment under real operating loads.
INA considers this one of the most technically demanding phases of the project. After testing is complete, the company expects the refinery complex to achieve nominal capacity during 2026. With a total value close to €700 million, the development stands as the largest investment in INA’s history and one of Croatia’s most significant industrial projects.
The program also includes a broad modernization of the Rijeka site, such as upgrades to existing facilities, new port infrastructure, storage silos, an enclosed coke transport system and a new electricity substation, the largest in the country. Altogether, these upgrades are transforming the refinery into a highly advanced regional facility with better energy efficiency, improved crude utilization and a higher share of high-value products.
Once operational, the unit is projected to lift diesel production by up to 30%, lowering Croatia’s dependence on fuel imports, especially during the peak summer tourist season. The project is also expected to eliminate the need for vacuum gas oil imports from European markets, much of which has traditionally been sourced from Russia, thereby reinforcing national energy security.
