Scale-Up Studies for the Dehydration of C₄₊ Alcohols into Drop-In Diesel Fuel

Herein, we demonstrate the production of liter quantities of drop-in diesel-range ethers from biomass-derived alcohols. We report scale-up results for the dehydration of a mixture of C4+ alcohols using powder and pellet zeolite Y catalyst in continuous flow and batch reactors. The activity of zeolite Y decreases with the introduction of an alumina binder. Large alcohols, as well as branched and secondary alcohols, increase the coke content over the pellet Y catalyst. The pellet formulation had lower carbon balances and selectivity to C10+ ethers, suggesting that the pellet formulation increases alcohol absorption and coke production. Crushing the pellet Y catalyst to smaller particle sizes does not recover the activity of zeolite Y in its powder form. Cold flow experiments show that particle agglomeration contributes to pressure buildup in the continuous flow reactor. C10+ ether blends can be produced in batch reactors at high alcohol conversion regimes. One liter of a diesel #2 blend was produced by scaling up this reaction. The final blend consists of a substantial portion of C10+ ethers (63.7 wt %), followed by heavy unknown products (27.4 wt %). The final alcohol and butyl ether concentration values were 7.3 and 1.5 wt %, respectively. The blendstock reported in this paper can satisfy diesel #2 ASTM standards for density, cloud point, flashpoint, and cetane number.