Diamond Green Diesel Holdings LLC (DGD) has filed an application with the California Air Resources Board (ARB) seeking carbon intensity (CI) certification for the Low Carbon Fuel Standard (LCFS) of renewable diesel (RD) pathways from distillers corn oil; rendered animal fat; and used cooking oil (UCO) at the Diamond Green Diesel LLC facility in Norco, Louisiana.
The Norco plant uses the UOP Ecofining Process to produce RD. The process hydrogenates triglycerides and free fatty acid feedstocks which are then isomerized to create a high-quality hydrocarbon fuel (RD). In addition to RD, the process produces a liquid petroleum gas vapor stream (LPG vapor); a liquid petroleum liquid stream (naphtha LPG); and a purge gas stream.
All of the co-product streams go to the adjacent Valero oil refinery to be separated into fuel gas, propane, and naphtha through a distillation process.
For the purposes of the CI certification, displacement credit was given to the fuel gas used as fuel gas for hydrogen production at the Valero refinery.
The plant receives two hydrogen streams from the refinery: a pure hydrogen stream and a H2S rich stream. DGD uses an amine scrubber to remove CO2 and H2S from the recycle hydrogen stream.
The rich diethanolamine (DEA) from DGD is regenerated at the Valero refinery. DEA regeneration involves the use of energy (steam and electricity) which was included in DGD’s Carbon Intensity calculation.
In all three cases, the RD is transported from the Norco plant to California via ocean tanker.
The proposed carbon intensities (gCO2e/MJ) for RD from each pathway are:
- Distillers corn oil: 27.42
- Rendered animal fat: 31.86
- UCO: 19.92