Croatia's INA Industrija Nafte DD has introduced feedstock into a new delayed coking unit (DCU) at its 90,000-b/d Rijeka refinery on the northern Adriatic coast, with the unit already running at about 70% of design capacity.

The refinery introduced feed on Sept. 1 following mechanical completion and commissioning, majority owner MOL Group said in a Sept. 21 release. The DCU has operated continuously since startup.

The unit has produced all key products at required quality, according to the company. INA anticipates the coker will increase diesel production by as much as 30% from the same crude volume once fully operational. The DCU converts heavy refinery residues into higher-value products.

MOL Group said the new unit will also eliminate Croatia's need to import vacuum gas oil (VGO) once fully operable.

"The start-up of the new unit went really well," said Zsuzsanna Ortutay, president of INA's management board. She said the DCU would improve the sustainability and profitability of INA's refining business while supporting energy supply in Croatia and the surrounding region.

The Rijeka upgrade represents a nearly €700 million investment. It sits within a combined €1.3 billion joint program by INA and MOL Group in refining and logistics modernization over the past 12 years.

INA plans to increase throughput and optimize process performance at the unit gradually. The company expects stable operation by yearend, followed by final plant performance testing and project closeout activities.

Project background

INA awarded a lump-sum, turnkey engineering, procurement, and construction contract for the coker to KT-Kinetics Technology SPA, a subsidiary of Maire Tecnimont SPA, in December 2019.

The scope covered a new delayed coking complex with coke handling and ship-loading facilities, a sour-water stripper, and amine recovery units. It also included modifications to the existing hydrocracker, sulfur recovery unit, utilities, and offsite systems. Plans further called for coke storage and a new marine jetty.

More than 60% of the existing refinery was expected to undergo work, according to Maire Tecnimont. The contractor valued the contract at about €450 million and initially scheduled completion for 2023 — a timeline the Sept. 1 startup ultimately exceeded by roughly two years.

The delayed coking project formed part of INA's broader Downstream 2023 New Course program. The strategy concentrated crude processing at Rijeka while converting INA's 44,000-b/d Sisak refinery into a site for bitumen, renewable, and potentially lubricant production, as well as a logistics hub.

Ownership of INA is split between MOL Group subsidiary MOL PLC at 49.1%, the Republic of Croatia at 44.8%, and private and institutional investors at 6.1%.

The watch item: whether the DCU reaches stable, full-design operation on schedule by yearend and passes final performance testing — the step that would trigger project closeout and confirm the projected 30% diesel yield gain.