This refinery should have docking points so that gas mining ships can dock with it to transfer over the deuterium directly to the refinery.
(If that won't work, the refinery should still have docking points so that transports like the Argo and Elysium can act as a go-between for the gas miners and the refinery, i.e. transport would dock with the gas miner, transfer the deuterium onboard the transport, then undock with the gas miner and dock with the refinery).
Are the gas miners in the screenshots able to undock with the refinery rings, or are they a permanent part of the mod?