To convert glycerol to gasoline range molecules

The bio-oil contains a significant amount of aldehydes, which are compounds characterized for its high activity providing to it unwanted properties for fuel applications. In this way to make it useful as liquid transportation fuel, bio-oil needs to be treated to enable the improvement of characteristics such as storage stability and octane number. In this way the furfural would be studied as a model compound of the aldehydes present in the bio-oil.

 

 

 

Experiment setup

Catalyst preparation

The catalysts were prepared by incipient wetness impregnation method (IWI). The various amounts of metal salts calculated according to the desired loadings were introduced onto the Hisil silica. After impregnation, the samples were dried at 110oC overnight and calcined at 400oC for 4 h.

Catalyst activity testing

The catalyst was located at the center of reactor and then reduced in hydrogen flow for 1 h. After the reduction, a model feed was supplied continuously to the reactor via a syringe pump together with a flow of hydrogen controlled by mass flow controller. Between the reaction, the products were analyzed online by GC analyzer.

 

Reaction over Pd/SiO2 Catalyst

Figure 1. Conversion and product yield of furfural conversion on Pd/SiO2at different temperature and W/F. H2: feed ratio = 25:1

Figure 2. Conversion and product yield of furfuryl alcohol conversion on Pd/SiO2at different temperature and W/F. H2: feed ratio = 25:1

Reaction Pathway over Pd/SiO2

 

The primary product furfuryl alcohol was observed from hydrogenation of furfural

The secondary product 2-methyl furan was formed by hydrogenolysis of furfuryl alcohol.

Figure 3. Conversion and product yield of furfural conversion on Cu/SiO2at different temperature and W/F. H2: feed ratio = 25:1

Figure 4. Conversion and product yield of furfuryl alcohol conversion on Cu/SiO2at different temperature and W/F. H2: feed ratio = 25:1

Reaction Pathway over Cu/SiO2

Proposed mechanism

The results show that hydrogenation of furfural at the carbonyl group was readily promoted over Cu/SiO2.

At elevated temperature, 2-methyl furan was found as a secondary product from the hydrogenolysis of furfuryl alcohol over this catalyst.

While furan was obtained as a major product over Pd/SiO2 via a decarbonylation of furfural.

It is suggested that the carbonyl-hydrogenolysed product, 2-methyl furan, can be an appropriate choice for gasoline octane booster (RON=131).