GLEAMING NEW units are being added to Bapco's Sitra refinery as the company moves into the future as a lean, efficient, complex and highly competitive international refiner.

The Bapco refinery has been vital to Bahrain's economy since it was built in 1936, providing significant revenue for a country whose oil production - at some 35,000 barrels per day (bpd) - is relatively small by Gulf standards.

Driven by competitive needs and changing product specifications in key markets, the export refinery brought two units online last year.

A new Gas Concentration Unit (GCU) wet gas compressor was inaugurated last July to replace eight gas engine-driven reciprocating compressors in the GCU which had been operating since 1944.

The $21.5 million project will, according to Bapco, result in lower maintenance costs and a decrease in annual throughput and conversion losses.

Much of Bapco's modernisation so far has, however, centred around environmental improvement both at the refinery itself and in the products it manufactures. Completion of the various Environmental Compliance Projects will, according to the company, enable it to fully comply with principal environmental regulations on air emission and refinery wastewater effluent introduced by the Bahrain government in 1999.

The $29.5 million kero-merox unit was inaugurated last November to significantly reduce lead sulphide discharge to the effluent system.

The project is seen by Bapco as a major step forward in its Environmental Improvement Programme, as the merox treatment of kerosene is more environmentally-friendly than the old process.

Previously, all jet fuel produced by Bapco was treated in lead sulphide kerosene treaters, using an obsolete, labour-intensive and environmentally-unfriendly process.

The No.1 lead sulphide plant was therefore replaced with two 25,000 bpd train Universal Oil Products (UOP) merox units.

The UOP merox process is a catalytic process in which the sulphur present as mercaptans is converted to less objectionable disulphides by oxidising them in an alkaline environment.

The introduction of unleaded gasoline to the Bahrain market in July 2000 in a $6.9 million project meant the removal of tetraethyl lead from Bahrain's gasoline supply.

Leaded gasoline continues to be blended at Sitra Tank Farm and loaded out at Sitra Wharf to tanker ships, solely for the export market.

Water effluent from the Sitra Tank Farm site usually contains free and dissolved hydrocarbons, as well as phenols and lead, as a normal consequence of tank farm operations.

A $1.6 million project to be completed this year will enable the transfer of these collected effluent streams back to the main refinery effluent treatment area.

There is a further source of lead in effluent from the lead sulphide Visbroken naphtha treatment unit. A $4 million, purely environmental, project is under way to replace this unit with a small-scale merox treater.

Desulphurisation project

Bapco fuel gas consists of process gases and Khuff gas. Khuff gas comes from outside the refinery, from the Khuff gas distribution network. The Khuff gas sulphur level meets current specifications. In the future, it is envisaged that Khuff gas sweetening will be done on the main gas source, outside of Bapco.

The refinery Desulphurisation Project has been proposed with the following process facility objectives: sweetening the sour process gases; providing additional sulphur plant capacity; providing sulphur plant tail gas treatment unit; providing sour water strippers; to utilise the real value of LPG in fuel gas.

The $140 million project is expected to start with basic engineering work in the second quarter of this year.

Control of Volatile Organic Compounds (VOCs)

An ongoing refinery programme to retrofit secondary roof seals to light product tankage such as gasoline and naphtha, and the on-site VOC pilot study to be planned for future phased implementation, will eventually result in compliance with new regulations.

It is anticipated that all regular tanks will have secondary roof seals fitted by 2006 at an estimated total cost of $7 million.

Bapco is also initiating a $55 to $70 million project to treat refinery wastewater biologically, and this is scheduled for completion by 2008.