Silleno project enters a new stage: Polymerisation unit construction begins

On the construction site of the future polyethylene production plant Silleno, earthworks have begun as part of the construction of the polymerisation unit. The update was shared by Silleno LLP, the project operator, via its official Telegram channel.

Source: Neftegaz

This polymerisation unit will become the second major production facility at the plant, responsible for manufacturing the final product — polyethylene. The EPC contractor for the unit is Tecnimont S.p.A. (Italy), working in consortium with SINOPEC Shanghai Engineering Co. (China).

Meanwhile, construction of the first key facility — the pyrolysis unit — is also progressing. The overall progress on this unit, including design, procurement, and construction, has exceeded 30%. Work at the site includes piling and foundation preparation: 10,200 piles out of 17,962 have been driven, and 5,300 m³ of concrete out of the 10,000 m³ planned for 2025 has been poured.

All works are being carried out on schedule, with particular attention to safety and quality. More than 775 personnel and 170 units of machinery are currently involved on-site.

About the Silleno Plant

The large-scale project is being developed in the National Industrial Petrochemical Technopark Special Economic Zone in Atyrau Region, Kazakhstan. Once commissioned, the plant will become one of the largest in Central Asia, enabling Kazakhstan to take a strong position in the global polyethylene market.

The design production capacity of the complex is 1.25 million tonnes per year, equivalent to about 1% of global capacity. The product range will include more than 20 grades of polyethylene for key industrial applications. Production will use licensed US technologies from Chevron Phillips and Univation.

The agreement to build the polymer complex was signed between KazMunayGas (KMG), SIBUR, and Sinopec on 19 April 2024. Construction works began in March 2025, with completion planned for 2028 and launch in 2029. Total project investment exceeds US $7 billion.

Key Project Facilities

1. Ethylene pyrolysis unit (Lummus technology, USA)
2. Ethylene polymerisation units (Chevron Phillips Chemical and Univation Technologies, USA)
3. Butene production unit (Axens, France)

Ownership structure:

1. KazMunayGas — 40%
2. Sinopec Overseas Investment Holding — 30%
3. SIBUR — 30%

Feedstock and Logistics

The primary feedstock for Silleno will be ethane supplied from a new gas separation complex (GSC) under construction at the Tengiz field. The GSC capacity is 9.1 billion m³ of dry gas per year, with 1.6 million tonnes per year of ethane allocated for the Silleno project. A new trunk pipeline will be built to transport the feedstock.

Work on the GSC and pipeline is being carried out by a joint Italian-Lebanese consortium Tecnimont S.p.A. + CCIC under an EPC contract signed in August 2025.

Infrastructure and Financing

In September 2025, Kazakhstan reached an agreement with the China Development Bank, which will provide US $530 million to support construction of the ethane and propane pipeline infrastructure in Atyrau Region.

Market Context

Polyethylene is a critical raw material for the production of pipes, packaging, insulation, household and industrial components, medical equipment, films, containers and many other widely used goods.

The Silleno plant is expected to replace up to 90% of Kazakhstan’s polyethylene imports. In 2024, domestic demand was about 300,000 tonnes, and is projected to rise to 400,000 tonnes by 2035. A significant share of this demand will be met by Silleno production.