STSI performs construction of facilities and plants in the Republic of Croatia and abroad.

In the Republic of Croatia, STSI has, independently or as a consortium partner, taken part in the construction of:

• Gas pipeline
  • Pula – Karlovac gas pipeline

• Refinery plants
  • Construction of the PSA 2 plant at SR (Sisak Refinery)
  • Construction of the Claus plant at SR
  • Construction of hydrocracking interconnecting pipelines at RR (Rijeka Refinery)
  • Construction of compressor stations
  • Construction of the biofuel system at SR
  • Construction of the PENEX low-temperature isomerization plant
  • engineering, procurement, construction supervision and commissioning (EPS)
  • Reconstruction of the plant for hydrodesulfurization of petrol and diesel fuel L/LCh – engineering, procurement, construction supervision and commissioning (EPS)
  • Construction of the CLAUS plant for the production of the elemental sulfur, phase I – engineering, procurement, construction supervision and commissioning (EPS)
  • Construction of the CLAUS plant for the production of elemental sulphur, phase II – engineering, procurement, construction supervision and commissioning (EPS)

• Oil and gas exploitation plants
  • Construction of well sites at all INA fields
  • Revitalization of existing pipelines by inserting composite pipes
  • Reconstruction of the aMDEA system at the CGS (Central Gas Station) Molve 3
  • Installation of cogeneration turbine blocks TEA 3 and TEA 4 at CGS Molve
  • EOR (enhanced oil recovery) project – construction of a CO2 injection system
  • Međimurje project – connecting gas pipeline and facilities of the Vučkovec field
  • Palmyra project – construction of a well gathering system, gas station and gas pipeline – engineering, procurement and construction supervision
  • Jazal project – construction of a well site and gas pipeline – engineering, procurement and construction (EPC)
  • Jihar project Stage 2 – Construction of a well gathering system, gas treatment plant with a compressor station – engineering, procurement and construction (EPC)

• Offshore plants
  • Construction of the supporting structure (jacket) of Ivana K platform
  • Modification of Ika A, Ida C, Ivana K and Katarina platforms