CORRECTED - Fuji Oil to boost asphalt-cracking unit capacity

(Corrects to 1,500 from 15,000 in 2nd-last paragraph)

TOKYO, May 14 (Reuters) - Japan's Fuji Oil Ltd plans to boost capacity of its Eureka thermal cracking unit by 6,000 barrels per day to 30,000 bpd by late June during planned maintenance, officials with parent AOC Holdings Inc (5017.T) said on Thursday.

The unit processes asphalt to gasoline and middle distillate.

The move, which is aimed at lowering crude oil purchase cost, is expected to have a positive impact on refining margins as the company expects the differential of Saudi Arabia's Arab Light and Arab Heavy grades to widen to $4 a barrel on average in the business year ending next March from $1.70 now.

The refiner will also raise the capacity of its vacuum distillation unit by 5,000 barrels per day (bpd) to 60,000 bpd at the company's sole Sodegaura refinery, east of Tokyo, AOC President Fumio Sekiya told reporters.

The refinery's first hydrogen-making facility with capacity to produce 15,000 cubic metres of hydrogen per hour is also being set up to avoid a hydrogen shortage during the refinery's maintenance that will last until around June 20.

Fuji Oil has planned to operate its 140,000 bpd crude distillation unit (CDU) at 97 percent of capacity on average in the business year that started in April, up from 93.9 percent a year earlier, a company spokesman said.

The refiner also plans to boost the jet fuel loading capacity for export to 1,500 kilolitres per hour from 800 kl/h around autumn, the spokesman added.

AOC, the holding company for oil producer Arabian Oil, also announced it would invest 55.5 billion yen ($581 million) in the five years ending March 2014. ($1=95.52 Yen) (Reporting by Osamu Tsukimori; editing by Sue Thomas)