Stenungsund Ethylene and Polyethylene Complex, Sweden

Stenungsund is an ethylene and polyethylene complex in western Sweden. The plant capacity has been expanded from 400,000t/yr to over 600,000t/yr. The project was due to be completed in the last quarter of 1999, to coincide with Stenungsund's usual maintenance and inspection shutdown, however technical problems delayed the onset of production. In February 2000 an extended cracker and a new Borstar polyethylene plant opened. The prolonged outage of the Stenungsund plant had the effect of increasing ethylene prices in Europe and forced Borealis to buy ethylene supplies on the spot market as a temporary measure.

After the set-up of the new cracker, the plant had a number of serious problems throughout 2000. This was mainly due to high volatile organic compounds (VOC) that led to excessive noise and flaring.

RETROFIT BORSTAR TECHNOLOGY

The cost of the expansion of both the ethylene and polyethylene parts of the plant was about $200 million (about 1.7 billion Swedish Kroner), although this does not factor in the cost of lost production. Around 45% of the total cost is expected to be caused by the decision to retrofit Borstar technology.

The technology and basic design have been supplied by Stone & Webster. They use patented Advanced Recovery System and the USC M-coil Furnace Technology. Foster Wheeler undertook the detailed engineering. This included detailed design of two 100,000t/yr ethylene heaters and related hot section, procurement of equipment and materials, and construction management. Foster Wheeler will undertake the project from its French office.

TROLL FIELD ETHANE FEEDSTOCK

The ethylene expansion will use ethane as a feedstock taken from the Troll field in the North Sea. This is to reduce the plant's dependence on naphtha and liquefied petroleum gas as feedstocks. The expansion also has the advantage of reducing Borealis' need to import ethylene for its polyethylene plant. There will be no increase in propylene output. The bulk of the propylene produced will probably go to Neste Oxo for the manufacture of phthalic anhydride and DEHP. The shutdown by Borealis forced Neste Oxo to reduce it capacity utilisation in parts of its Stenungsund plant.

Thanks to this huge expansion, the production capacities are at an all-time high. This includes ethylene at 610,000t/yr, propylene at 200,000t/yr, methyl tertiary butyl ether at 50,000t/yr and blyethylene at 590,000t/yr.

BIMODAL POLYETHYLENE

Borstar has been retrofitted to Borealis' polyethylene facilities in Stenungsund. The Borstar process uses a specialised Ziegler-Natta catalyst known as BC1. Borstar allows the company to use the bimodal production technology which it is also installing at its Borouge plant in the United Arab Emirates and is already in place at Porvoo, Finland. The bimodal polyethylene capacity will be 225,000t/yr. The market for bimodal polyethylene is estimated by the company to be growing at roughly four times the rate of the ordinary polyethylene market.

Kvaerner process undertook the engineering, procurement and construction (EPC) for the polyethylene plant. The first bimodal polyethylene was expected to be produced in June 2000.

ENVIRONMENTAL CONCERNS

The nitrogen oxide output will increase to 400,000t/yr from 350,000t/yr before the expansion, but this will still be within the plant's permitted limits of 450,000t/yr.

The plant's energy consumption is expected to be 20% lower. This is a particularly important consideration in Sweden, where strong environmental traditions have led it to pledge to decommission its nuclear power stations putting a premium on all forms of energy saving.

BOREALIS' INVESTMENT STRATEGY

The plant is entirely owned by Borealis AB, the Copenhagen-based chemicals group. Borealis is currently the largest producer of polyolefins in Europe and the sixth largest in the world. Borealis is jointly owned by Norway's Statoil, Austria's OMV and the International Petroleum Investment Company (IPIC) of Abu Dhabi. Statoil is a long standing owner. The International Petroleum Investment Company and OMV got involved in 1997, when Neste sold its stake.

Borealis wants to make Stenungsund a truly world-scale plant in order to reap major economies of scale. The growth in Middle East petrochemical production is expected to put European producers under greater pressure; hence, the greater emphasis on efficiency. Borealis is making its European production more efficient. It is closing its compounding facilities in Hamburg, Germany, as a result of low utilisation and profitability. It is expanding into the Middle East through a joint venture with ADNOC in the United Arab Emirates. Borealis is also re-organising its marketing arrangements.