Animal fats valorization to green transportations fuels: From concept to industrially relevant scale validation.

The potential of animal fats hydroconversion is experimentally investigated and validated in industrially relevant scale via the production of 100 L of transportation fuels. The experimental testing has indicated that mild hydrotreatment conditions are associated with low hydrogen consumption without significantly penalties in product quality. The optimal operating conditions (pressure of 6.89 MPa, H2/oil ratio of 84.95 Sm3 and LHSV of 1 hr-1) identified were also applied in the industrially relevant scale hydroprocessing pilot to validate the scale-up potential of the technology. The produced fuel is characterized by 5 wppm sulphur, 79.3 cetane index and 44.4 MJ/kg heating value, offering an advantage in compression ignition engines. The produced fuel can be blended up to 20% v/v with fossil diesel rendering a high bio-content diesel abiding by the EN 590 standard. It was found that, up to 20% per volume can be added in diesel without exceeding the requirements for CFPP standards for Greek winter diesel. Towards the commercialization of the technology with respect to the animal fats logistics, a dedicated 6-month storage stability study revealed that animal fats can be stored for up to three to four months at ambient conditions. The findings, indicate that the suggested technology is mature technology as applied successfully in the industrially-relevant-scale providing also the process data.

Oxidative stability of waste cooking oil and white diesel upon storage at room temperature.

Renewable diesel fuels are alternative fuels produced from vegetable oils or animal fats. Catalytic hydrotreating of waste cooking oil (WCO) was carried out at pilot-plant scale and a paraffinic diesel, called "white" diesel was obtained. The white diesel and WCO samples were stored for one year at room temperature under normal atmospheric conditions, but not exposed to sunlight. Viscosity, total acid number (TAN), induction period (IP), carbonaceous deposits, density, cold flow properties, distillation and water content were monitored. TAN and density of the white diesel stored in conventional bottles changed from 0 to 0.221 mg KOH/g and from 787 to 838 kg/m(3), respectively. The remaining parameters did not vary significantly. Water content of WCO increased from 482 to 2491 mg/kg, TAN from 0.744 to 0.931 mg KOH/g, whereas viscosity, IP and carbon residues fluctuated mildly. The results are indicative of the white diesel's stability, rendering it suitable for prolonged storage.

Hydrotreating of waste cooking oil for biodiesel production. Part II: effect of temperature on hydrocarbon composition.

This study focuses on the use of waste cooking oil (WCO) as the main feedstock for hydrotreatment to evaluate the effect of temperature on the product hydrocarbon composition. A qualitative analysis was initially performed using a GC x GC-TOFMS indicating the presence of mainly paraffins of the C15-C18 range. A quantitative analysis was also performed via a GC-FID, which gave both n-paraffins and iso-paraffins in the range of C8-C29. The results indicate that hydrotreating temperature favors isomerization reactions as the amount of n-paraffins decreases while the amount of iso-paraffins increases. For all experiments the same commercial hydrotreating catalyst was utilized, while the remaining operating parameters were constant (pressure=1200 psig, LHSV=1.0 h(-1), H(2)/oil ratio=4000 scfb, liquid feed=0.33 ml/min, and gas feed=0.4 scfh).

Hydrotreating of waste cooking oil for biodiesel production. Part I: Effect of temperature on product yields and heteroatom removal.

Hydrotreating of waste cooking oil (WCO) was studied as a process for biofuels production. The hydrotreatment temperature is the most dominant operating parameter which defines catalyst performance as well as catalyst life. In this analysis, a hydrotreating temperature range of 330-398 degrees C was explored via a series of five experiments (330, 350, 370, 385 and 398 degrees C). Several parameters were considered for evaluating the effect of temperature including product yields, conversion, selectivity (diesel and gasoline), heteroatom removal (sulfur, nitrogen and oxygen) and saturation of double bonds. For all experiments the same commercial hydrotreating catalyst was utilized, while the remaining operating parameters were constant (pressure=1200 psig, LHSV=1.0 h(-1), H(2)/oil ratio=4000 scfb, liquid feed=0.33 ml/min and gas feed=0.4 scfh). It was observed that higher reactor temperatures are more attractive when gasoline production is of interest, while lower reaction temperatures are more suitable when diesel production is more important.

Hydrocracking of used cooking oil for biofuels production.

Hydrocracking of used cooking oil is studied as a potential process for biofuels production. In this work several parameters are considered for evaluating the effectiveness of this technology, including hydrocracking temperature, liquid hourly space velocity (LHSV) and days on stream (DOS). Conversion and total biofuels production is favored by increasing temperature and decreasing LHSV. However moderate reaction temperatures and LHSVs are more attractive for diesel production, whereas higher temperatures and smaller LHSVs are more suitable for gasoline production. Furthermore heteroatom (S, N and O) removal increases as hydrocracking temperature increases, with de-oxygenation being particularly favorable. Saturation, however, is not favored with temperature indicating the necessity of a pre-treatment step prior to hydrocracking to enable saturation of the double bonds and heteroatom removal. Finally the impact of extended operation (catalyst life) on product yields and qualities indicates that all reactions are affected yet at different rates.

Hydrocracking of vacuum gas oil-vegetable oil mixtures for biofuels production.

Hydrocracking of vacuum gas oil (VGO)--vegetable oil mixtures is a prominent process for the production of biofuels. In this work both pre-hydrotreated and non-hydrotreated VGO are assessed whether they are suitable fossil components in a VGO-vegetable oil mixture as feed-stocks to a hydrocracking process. This assessment indicates the necessity of a VGO pre-hydrotreated step prior to hydrocracking the VGO-vegetable oil mixture. Moreover, the comparison of two different mixing ratios suggests that higher vegetable oil content favors hydrocracking product yields and qualities. Three commercial catalysts of different activity are utilized in order to identify a range of products that can be produced via a hydrocracking route. Finally, the effect of temperature on hydrocracking VGO-vegetable oil mixtures is studied in terms of conversion and selectivity to diesel, jet/kerosene and naphtha.