Southeast biomass conference to feature renewable hydrocarbons panel

Posted October 1, 2010, at 9:13 a.m. CST

Join biomass peers at BBI International's Southeast Biomass Conference & Trade Show, Nov. 2-4 at the Hyatt Regency in Atlanta.

One of the featured panels at the event is Technological Pathways to Renewable Hydrocarbons. The phrase "renewable hydrocarbons" has been hot in renewable energy circles, mainly because it implies drop-in biofuels that are almost molecularly identical to the fossil-based fuels they intend to replace compared to alcohol- or ester-based biofuels, thereby minimizing any infrastructure integration issues.

Philip Steele, professor at Mississippi State University, will give a presentation on refinery options to produce renewable hydrocarbons from hydroprocessed bio-oil. "Fast pyrolysis is becoming an important thermal route to convert biomass to liquid fuels," Steele said, qualifying the statement with, "however, raw bio-oils have a number of negative properties such as high acidity, high water content, lower heating value and variable viscosity over time. These characteristics have hampered their commercialization for production of transportation fuels, as well as being problematic in fluidized catalytic cracking coprocessing in standard refinery units."

Steele went on to say that the negative bio-oil properties largely result from the high proportions of oxygenated compounds present in them, and that all of these undesirable properties can be improved by hydroprocessing of the raw bio-oil. He conducted a study in which they pyrolyzed pine wood in an auger reactor at 450 degrees Celsius. The bio-oil was upgraded by a single-stage mild HP in a batch autoclave, he said.

"Numerous catalysts were tested until we successfully obtained the upgraded bio-oil with low acidity, good miscibility with hydrocarbons, and high volatility," he said. After hydroprocessing, the refined bio-oil underwent phase separation, which resulted in an aqueous phase, some gases and a light oil phase. The upgraded bio-oil was subsequently characterized by several analytical methods, including elemental analysis. The oil was then further distilled into four fractions by boiling point range and compared with petroleum diesel, gasoline and jet fuels by simulated distillation technique. Steele will discuss his findings at the conference.

Another panelist will be Jeff Sherman, executive vice president and chief business development officer with GRT Inc. Sherman's speech will detail the BTF Process, which stands for biomass to fuels. While piloted at the scale of 10 barrels (420 gallons) a day, he said GRT is commercializing the BTF Process, which converts most biomass feedstock into pure hydrocarbon fuel for use directly as high-octane gasoline or bio jet fuel blend stock. "Although there is sufficient nonfood biomass available in the U.S. to supply approximately one-third of the U.S. gasoline market, there are no cost-effective technologies available to covert biomass to gasoline," he said, explaining that his company's gas-to-liquids technology converts biogas directly to liquid fuels without the need to remove the carbon dioxide.

"The process is a bromine-based methane conversion process that converts the biogas from each ton of biomass into more than 50 gallons of hydrocarbon fuel," Sherman said. "In the process, bromine functions essentially as a catalyst to activate methane thereby facilitating its conversion to gasoline molecules." He said the bromine is captured for continuous reuse in the process, and the exothermic reactions produce valuable waste heat that can be captured and reused elsewhere, contributing to the very low overall carbon footprint of the process.

Auburn University Professor of Energy & Fiber Crops, David Bransby, will give a review of the current drop-in replacement cellulosic biofuel technologies. Bransby will discuss both biological and thermochemical routes to renewable hydrocarbons, and what technologies work at which scales. The presentation will provide a detailed review of these technologies, plus commercialization headway, and suitability of the technologies to different feedstock and environments. "The objective will not be to choose a winner, but rather, to identify strengths and challenges related to each," he said.

The moderator will be Robert Diltz with the Air Force Research Laboratory.

To register for BBI International's Southeast Biomass Conference & Trade Show, produced jointly by Biomass Power & Thermal and Biorefining magazines, click here.