Roger N. Hilten

Production of aromatic green gasoline additives via catalytic pyrolysis of acidulated peanut oil soap stock.

Catalytic pyrolysis was used to generate gasoline-compatible fuel from peanut oil soap stock (PSS), a high free fatty acid feedstock, using a fixed-bed reactor at temperatures between 450 and 550°C with a zeolite catalyst (HZSM-5). PSS fed at 81 gh(-1) along with 100 mL min(-1) inert gas was passed across a 15 g catalyst bed (WHSV=5.4h(-1), gas phase residence time=34s). Results indicate that fuel properties of PSS including viscosity, heating value, and O:C ratio were improved significantly. For PSS processed at 500°C, viscosity was reduced from 59.6 to 0.9 mm(2)s(-1), heating value was increased from 35.8 to 39.3 MJL(-1), and the O:C ratio was reduced from 0.07 to 0.02. Aromatic gasoline components (e.g., BTEX), were formed in concentrations as high as 94% (v/v) in catalytically-cracked PSS with yields ranging from 22% to 35% (v/v of PSS feed).

Continuous catalytic upgrading of fast pyrolysis oil using iron oxides in red mud

A catalyst composed primarily of magnetite was prepared from red mud, via H2 reduction at 300 °C, which significantly increased the surface area. Ammonia and CO2 temperature programmed desorption indicated both acid and base active sites. Continuous reaction studies conducted with individual compounds, mixtures of model compounds, and water extracted fast pyrolysis oil indicated that acetone was the primary product from acetic acid, and acetone and 2-butanone from acetol. Levoglucosan went down the same pathway, since it formed acetic acid, formic acid, and acetol. Total conversion and yields approached 100% and 22 mol% ketones at 400 °C and a W/F of 6 h for a model mixture and 15–20 mol% ketones at W/F 1.4–4 h and 400–425 °C using water extracted oil. Space time yields approached 60 g ketones per L-cat per h for the model mixture and 120 g per L-cat per h for a commercial oil. The catalyst simultaneously reduced acidity, allowed recovery of carbon, and generated upgradable intermediates from the aqueous fraction of fast pyrolysis oil in a “continuous” process.

Pyrolysis Characteristics of Forest Residues Obtained from Different Harvesting Methods

Although forests promise an abundant supply for residue biomass for biorefining and biopower applications, heterogeneity generated in residue due to collection methods or selection process (limb, top, and understory etc.) may influence biofuel production in both the thermochemical and fermentation pathways. This article focuses on effects of collection methods on the fuel properties, thermochemical decomposition behavior, and properties of pyrolysis bio-oil and char. Forest residues studied in this research include: clean wood chips (CW), horizontal grinder material (GM), pre-commercially thinned biomass chips (PC-chips), biomass chips produced from pine limbs and tops (T-chips), and biomass chips produced from hardwood understory stems and pine limbs and tops (TU-chips). All biomass samples were characterized by measuring bulk density, moisture, chemical composition (cellulose, hemicellulose, lignin, ash, and extractives), energy density, proximate analysis (moisture, fixed carbon, volatile matter, and ash), and ultimate (C, H, N, S, O) analysis. Pyrolysis was performed on partially dried biomass samples to produce char and bio-oil. The yields of pyrolysis products were calculated. Char was characterized by proximate and ultimate analysis, energy density, and iodine number; and, bio-oil was characterized by pH, viscosity, ultimate analysis, energy density, and water content. In addition, fixed carbon yields, char carbon efficiency, and energy conversion efficiency of char were also calculated. Results showed that the GM had the highest ash content (5.9%) and the lowest energy density (17.03 MJ/kg) among all forest residues evaluated. TU-chips had higher concentration of extractives which resulted in an additional decomposition peak at 300°C beyond the main peak which appeared at 370°C responsible for decomposition of cellulose and hemicelluloses in thermogravimetric analysis. Results from this study showed no significant difference in char and bio-oil yields in the various forest residues evaluated; however, GM char which was large in ash content, because of contamination by soil inclusion had lower heating value and adsorption capacity. All residues evaluated produced bio-oil with similar fuel properties.

Using Green Roofs and Other BMPs to Reduce the Need for Stormwater Retention Capacity Requirements

Many factors are at play in the choice of stormwater BMPs as part of a stormwater management plan. Factors such as costs for land area and construction and the effectiveness of BMPs are important variables to consider when implementing low impact development strategies. A study was conducted to briefly compare stormwater BMP costs and benefits while focusing primarily on the effectiveness of green roofs to mediate stormwater using computer simulation and field study. Simulations were run using HYDRUS-1D for 24-hour design storms to determine peak flow, retention and detention time for runoff. Storm data collected at an Athens, GA green roof study were used to validate HYDRUS-simulated runoff. The study site was atop a utility room for University of Georgia Science Library and consisted of a 37 m 2 (400 ft 2 ) modular block green roof containing engineered soil and several Sedum species. The study revealed that rainfall depth per storm strongly influences the performance of green roofs for stormwater mitigation, providing complete retention of small storms (< 2.54 cm) and detention for larger storms.