Low sulphur specs have been put in place on diesel for environmental reasons- and not enough home heating fuel being made to permit diversion of that cut around the deep hydrotreaters required to meet that spec, even assuming the vehicular sulphur specs don't apply to the heating fuel. 'Nuff said?

Just wait- major sh*t is going to hit the fan in 2020 when lower sulphur specs come into play for ship fuel. Low sulphur bunker just doesn't exist, and diesel ($$$) is the only option. Not only that, but without bunker to dump the resid stream into, refineries will be drowning in resid...Fortunately, a client of mine has been developing a solution- a way to cheaply generate a low sulphur bunker from resid. We just hope he's on-stream in time to take advantage of the whole mess!

I think all distillates have low S requirements today. Long ago S was lower in gasoline because reformer catalyst could not tolerate it. Most reformer product went into gasoline , so gasoline had low S ; I think that was the cause of the former relatively higher price of gasoline
. Amoco made more reformeate than others because they used a lot for polyester ( xylene > terepthalic acid ) and unleaded high octane.