Ann: Killanoola Project Potential Up To 93 mmbbls, page-2387

Actually a refinery produces (refines) crude oil into petrol, jet fuel, kerosene, diesel fuel, fuel oil, etc. The sulfur reduction is an end product treatment process that reduces said sulfur content from each type of fuel. Each type of fuel will require a different reduction process - AU has been behind on this for decades.

Per unit volume it is cheaper to ship fuel from Singapore - which is why the Government has the Fuel Security Services Payment (FSSP) to keep refineries open for security purposes (and make better quality fuels in the process):
https://www.energy.gov.au/government-priorities/energy-security/australias-fuel-security/fuel-security-services-payment

HC is an open forum, if you don't understand that then too bad ...............................................