Petroleos del Norte S.A. (Petronor) installed a new 5,050 b/sd HF alkylation unit this past April at its Somorrostro refinery in Bilbao, Spain (Fig. 1).
Alkylate from the unit-designed by Phillips Petroleum Co.-has increased unleaded gasoline production by 10%.
Petronor credits European Community (EC) regulations affecting gasoline production, plus government tax incentives, for stimulating an increased demand for lead-free premium and superpremium (95 RON) gasolines in EC countries.
In Europe, says Petronor, motor octane number (MON) requirements for lead-free gasolines are critical.
The refinery processes a variety of crudes from more than 20 countries. About 30% of the crude slate is Maya, with other major supplies from the Middle East, Africa, and Europe.
The Somorrostro refinery produces mainly fuels-LPG, gasolines, kerosine, automotive and heating gas oils, and fuel oils. Other products include sulfur, propylene, paving asphalts, naphthas, and solvents. The refinery flow scheme is shown in Fig. 2.
Approximately 50% of the refinery's products are sold in Spain, either directly to consumers or to marketers and dealers. The balance of the products are exported. About 20-30% of refinery output goes to Europe, with 25% to North America, Asia, and Africa.
The Petronor unit initially produced premium unleaded gasoline with an average octane ([R+M]/2) of greater than 97.0, using a feed-stream consisting primarily of butane. Guaranteed alkylate design value was a minimum of 94.6, using design feedstocks.
The new unit features elevated acid coolers and a secondary acid-storage tank below the level of the other HF-containing vessels (Fig. 3).
Phillips' reactor design is a self-circulating system. This scheme eliminates the need for in-reactor stirrers and excludes or reduces the need for circulating pumps, shaft seals, and gasketed connections in the reactor circuit, says Phillips.
Phillips assisted Petronor by reviewing engineering and vendor drawings of critical equipment, inspecting critical equipment, training Petronor personnel, and helping during start-up.
Throughput of the unit has varied, but has been as high as 4,600 b/sd, depending mostly on feedstock availability. Petronor declined to provide economic information, but expects the unit to be profitable and provide a reasonable payback.
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