In this guide we will discuss how to feed fractionates hydrogen that is tacked 4 items high without needing a return line. This means that, combined with proliferator, the fractionates are now 8 times as productive as they used to be before item stacking and proliferation. Below is also a blueprint for the fractionators producing deuterium along with a blueprint based on particle colliders.

If you are just here for the blueprints, here they are:

You will first want to have build the production lines for the proliferator, there is a guide and blueprints for that available here: https://auluftwaffles.com/2022/01/22/mk-i-mk-ii-and-mk-iii-proliferator-blueprint-and-spray-coater-dyson-sphere-program/

In the past the normal practice for fractionating hydrogen to deuterium was to use a return line to feed any excess hydrogen back to the input. That works fine when items are piled only 1 high, but it does not work when items are piled 4 high. This is because there is no guarantee that the remaining hydrogen is piled 4 items, high, it could be anything depending on what all of the fractionators needed. The solution is to feed any excess hydrogen into another transportation station to feed the hydrogen back into any other production lines.

This means that you can feed in hydrogen piled 4 items high and push through much more hydrogen through the fractionates to increase the output rate of deuterium. Together with the Mk.III proliferator that means the fractionator converts 2% of hydrogen to deuterium instead of 1%, now only 50 fractionates are needed to produce a Mk.III conveyor belt piled 4 items high. There are a few caveats which we will discuss next.

First, it takes 12.5 fractionates to produce 30 deuterium per second. This means that only 12 fractionates can be used before needing to use an automatic pillar to pile deuterium to 2 items high because the 13th fractionator would jam up blocking the hydrogen from going further. I used the standard automatic piled and splitter combination to pile the deuterium to 4 items high before feeding it into a transportation station.

So there you have it! You now know how to use proliferators on hydrogen belts that are piled 4 items high.