A system and process for refining crude oil to produce higher-purity, cleaner-burning designer fuels with reduced emissions. The crude oil may be treated with viscosity-reductant additives, which reduces viscosity by up to 50% and increases API gravity by more than 2 points. The method of spray-cracking and vacuum-flashing of crude oil separates light end chains and heavy end chains inside the reactor. The vapor is condensed into designer fuels like bunker, diesel, jet/kerosene fuel, naphtha and gasoline fuel using multi-stage horizontal reverse condensate-condenser. The GVF centrifuges are configured to separate targeted fuels of desired density value as per their ideal fuel densities, which carry out centrifugal polishing to generate targeted fuel products of desired density and hydrocarbon molecules of desired purity values. These designer fuels are further treated with desulfurization additive.