Catalytic hydrotreatment of humins into cyclic hydrocarbons over solid acid supported metal catalysts in cyclohexane

Humins are common undesirable sideproducts during many acid-catalyzed reactions in renewable biomass platform conversion. However, few studies have been reported to the efficient utilization of humins.For the first time, the selective catalytic conversion of biomass-derived humins into cyclic hydrocarbons with high conversion rate and selectivity is presented using a home-made Ru/W-P-Si-O bifunctional catalyst. The multistage polymerization structure of humins was studied through controlled experiments.Results show that the CAC bond network can be efficiently depolymerized at a mild reaction temperature of 340–380 °C, catalyzed by the cooperative catalysis of nano-Ru particles and porous strong Lewis solid acid. Particularly, 95.4% conversion of humins was achieved under the optimal condition with up to 88.3%yield of cyclic hydrocarbons. The detailed composition after liquefaction was also analyzed. This study paves the way for the efficient production of cyclic and aromatic hydrocarbons from furan-derived humin polymer through Lewis acid-catalyzed Diels–Alder reactions between furan rings.

Catalytic hydrotreatment of alkaline lignin and its consequent influences on fast pyrolysis

The current state of lignin has been characterized by these three:(1)as one of the main components in lignocellulosic biomass with an abundant amount;(2)not be taken seriously but treated as a waste product;(3)underutilized due to a complex and stubborn structure.However,lignin can be a rich source for hydrocarbons and aromatic compounds when gives appropriate utilization.In this work,we have studied the hydrotreatment of alkaline lignin(AL)under relatively mild conditions and further investigated the characterization of hydrogenated lignin(HL),especially the behavior during fast pyrolysis.The recovery of the HL decreased with increasing reaction temperature from 60 wt.%to 41 wt.%in the range of 150-250℃.The hydrotreated products were analyzed using Elemental Analysis,FTIR(for HL)and GC-MS(for bio-oil).The HL samples were found to have a higher hydrogen/carbon atomic effective ratio(H/C_(eff) ratio)and a higher degree of saturation than AL.Compared to the internal structure of the lignin before and after hydrotreatment,the side chain groups were removed from AL during the process.After that,from the fast pyrolysis of HL,it was observed that more light hydrocarbons and aromatic compounds were formed than that of AL.Furthermore,fast pyrolysis in the hydrogen atmosphere revealed that more volatile fractions were released compared to the Helium atmosphere.The total olefins yield was increased for HL compared AL from 1.02 wt.%to 3.1 wt.%at 250℃for 7 hours.This study of HL is instructive to some extent for the industrial utilization of lignin.

Egyptian heavy vacuum gas oil hydrotreating over Co-Mo/CNT and Co-Mo/γ-Al2O3 catalysts

The catalytic activity of CoMoS /CNT towards the Egyptian heavy vacuum gas oil hydrotreating was studied. The delivered CNT was functionalized with 6 mol /L HNO_3. The CNT were loaded with 12% MoO_3( by weight) and 0.7 Co /Mo atomic ratio with impregnation methods. The γ-Al_2O_3 catalyst was also prepared by impregnation method to compare both catalysts activities.The analysis tools such XRD,Raman spectroscopy,TEM,and BET were used to characterize the catalysts. The autoclave reactor was used to operate the hydrotreating experiments. The hydrotreating reactions were tested at various operating conditions of temperature 325-375 ℃,pressure 2-6 MPa,time 2-6 h,and catalyst /oil ratio( by weight) of 1 ∶75,1 ∶33 and 1 ∶10. The results revealed that the CoMoS /CNT was highly efficient for the hydrotreating more than the CoMoS /γ-Al_2O_3. Also, the hydrodesulfurization( HDS) increased with increasing catalyst /oil ratio. Additionally,results showed that the optimum condition was temperature 350℃,pressure 4 MPa,catalyst /oil ratio of 1 ∶75 for 2 h. Furthermore,even at low CoMoS /CNT catalyst /oil ratio of 1 ∶75,an acceptable HDS of 77.1% was achieved.

Hydrogen solubility prediction for diesel molecules based on a modified Henry equation

Diesel hydrotreatment removes heteroatoms and polycyclic aromatics in diesel in the presence of highpressure hydrogen gas.The hydrogen solubility is the basis for hydrogen consumption prediction and process design/optimization.In the presented study,we established a method to predict the hydrogen solubility of diesel molecules and mixture.A modified Henry equation was proposed to illustrate the hydrogen solubility variation among the temperature and pressure.The parameters of the modified Henry equation for typical molecules were regressed from literature data.Then we established an empirical correlation between the parameter and the structure and property of molecules.The method was then combined with a molecular-level compositional model to accurately predict the hydrogen solubility in diesel,illustrating the validity of the method.

Bio-Oil Extracted of Wet Biomass of the Microalga <i>Monoraphidium</i>sp. for Production of Renewable Hydrocarbons

Renewable hydrocarbons refer to fuels consisting of hydrocarbons of 10 to 20 carbon atoms, produced from biomass, and free of oxygen. Hydrocracking, hydrodeoxygenation and hydrotreatment processes for the production of renewable hydrocarbons are described in the literature. Microalgae have been targeted in recent years to synthesize biomass that can be used in the production of biofuels, such as renewable hydrocarbons, biodiesel or ethanol second generation. In this context the lineage Monoraphidium sp. was selected from previous ecophysiological studies and its potential to produce lipids to develop this research related with the extraction of the bio-oil of the wet biomass of Monoraphidium sp. through heat treatment. Consecutively the bio-oil was used as raw material for the production of hydrocarbons through hydrocracking and hydrodeoxygenation processes (HDO) as: decarbonylation, decarboxylation, dehydratation, with in situ production of hydrogen from liquid-phase reforming of glycerol. The reactions were carried out under two different temperature conditions, 350°C and 300°C, respectively, for 1 h and using ruthenium alumina catalyst (Ru/Al2O3). The results showed the bio-oil processing route at a temperature of 350°C promising for the production of hydrocarbons achieving a conversion of 81.54%.