Jerome E. Cooper

Life-Cycle Assessment of Pyrolysis Bio-Oil Production*

As part of the Consortium for Research on Renewable Industrial Materials’ Phase I life-cycle assessments of biofuels, lifecycle inventory burdens from the production of bio-oil were developed and compared with measures for residual fuel oil. Bio-oil feedstock was produced using whole southern pine (Pinus taeda) trees, chipped, and converted into bio-oil by fast pyrolysis. Input parameters and mass and energy balances were derived with Aspen. Mass and energy balances were input to SimaPro to determine the environmental performance of bio-oil compared with residual fuel oil as a heating fuel. Equivalent functional units of 1 MJ were used for demonstrating environmental preference in impact categories, such as fossil fuel use and global warming potential. Results showed near carbon neutrality of the bio-oil. Substituting bio-oil for residual fuel oil, based on the relative carbon emissions of the two fuels, estimated a reduction in CO2 emissions by 0.075 kg CO2 per MJ of fuel combustion or a 70 percent reduction in emission over residual fuel oil. The bio-oil production life-cycle stage consumed 92 percent of the total cradle-to-grave energy requirements, while feedstock collection, preparation, and transportation consumed 4 percent each. This model provides a framework to better understand the major factors affecting greenhouse gas emissions related to bio-oil production and conversion to boiler fuel during fast pyrolysis. This report has been produced as part of the Consortium for Research on Renewable Industrial Materials (CORRIM) Phase I reports on the life-cycle inventory (LCI) and life-cycle impact assessment (LCIA) studies of biofuels. CORRIM’s goal is to provide a database of information for quantifying the environmental impacts and economic costs of biofuels from woody biomass through the stages of collection, fuel conversion, and combustion in the United States. Life-cycle assessment (LCA) has evolved as an internationally accepted way to analyze complex impacts and outputs of a product and the corresponding effects on the environment. An LCA can provide the most comprehensive method to assess net carbon emissions and their associated impacts for fossil and biofuels evaluated under similar uses. The environmental outcomes of an LCA can accurately target the source of impacts, including where, when, and how they occur throughout a product’s life. The LCA process can provide characteristics such as global warming potential (GWP) and fossil fuel use that can be useful on a regional, national, or global scale. Outcomes from LCAs can be used to suggest more ‘‘environmentally friendly’’ products or sustainable production methods and may also provide insights regarding raw material conservation and emissions and waste output reduction. LCIA aggregates the inventory data and classifies them into the type of environmental impact to which they contribute, for example, GWP. Comparisons of the emission outputs of bio-oil with a relevant fossil fuel

Detecting Juvenile Wood in Southern Pine Lumber by Measuring Phase Shift

Identification of juvenile wood in green lumber following sawing would allow for segregation of juvenile wood from mature wood and application of special drying procedures to reduce warp. A dielectric means to detect juvenile wood by analysis of the real and imaginary signal components was applied via adjacent electrodes. Juvenile wood was successfully differentiated from normal wood by comparison of the imaginary signal component.

Estimating lumber strength with radio frequency scanning

Abstract The amount of lumber graded by machine stress rating (MSR) has continued to increase since the development of the technology in the early 1960s. Accuracy of lumber strength estimation by X-ray method is reported to be equal to that of MSR. This study examined whether lumber specific gravity and strength can be accurately estimated with radio frequency waves if the moisture content influence in a signal passed through the lumber thickness can be eliminated. Strength of a radio frequency signal passed through the lumber thickness was measured at 6.35 mm intervals along the length of lumber central axis. A linear regression predictive equation was estimated relating modulus of rupture (MOR) to measured signal voltage. Correction for the influence of moisture content on MOR resulted in a predictive equation with an R 2 of 0.59. Validation results based on the developed equation gave an R 2 of 0.67. The results indicate potential for accurate radio frequency estimation of MOR if adequate correction for moisture content influence is performed.

Demonstration results from greenhouse heating with bio-oil.

Abstract Bio-oils from loblolly pine (Pinus taeda) and white oak (Quercus alba) wood were produced by the laboratory scale auger reactor located at the Department of Forest Products, Mississippi State University (MSU). The bio-oils were esterified to boiler fuel by a technology developed at MSU. The testing of esterified bio-oil combustion was performed at Natchez Trace Greenhouses located in Kosciusko, Mississippi. At the greenhouse facility an idled natural gas/diesel boiler was retrofit with a highly aerated fuel injection system. Fifteen gallons of loblolly pine esterified boiler fuel and 15 gallons of white oak boiler fuel were successfully combusted in the retrofit boiler.

Detecting Compression Wood in Green Loblolly Pine with Radio Frequency

Compression wood is formed on the lower side of leaning softwood trees stem. High density and high microfibril angle lead to a very high longitudinal shrinkage compared to that of normal wood. This shrinkage leads to a high degree of warp and resultant value loss in lumber during drying. Detection of compression wood in green lumber would allow segregation of the lumber for special handling or product designation and reduce value loss from warpage during drying. A dielectric method was tested to differentiate compression from normal wood in green loblolly pine lumber. Compression wood produced a considerable increase in the phase shift of an applied radio frequency signal. A threshold value was determined, tested, and resulted in 95%, 100%, 95%, and 80% successful differentiation of compression from normal wood in lumber for 100, 500, 1000 and 5000 kHz frequencies, respectively.

The Differential Thermal Response of Knots and Clear Wood Following Rapid Heating

This study correlated the differential clear wood versus knot wood thermal response to rapid heating for 12 wood species to differences in specific gravity, equilibrium moisture content, extractives content, and microfibril angle. It was found that the relative levels of these variables explain much of the observed difference in clear vs. knot wood temperature following rapid heating. Rapid heating resulted in cooler knot wood temperatures which differ from hotter knot wood temperatures found by previous researchers for longer-term heating.

Dielectric Detection of Knots in Green Red Oak and Southern Pine Lumber

Forest products industry automation requires accurate detection of knots in lumber. A radio frequency system has been patented and commercialized that relies on signal attenuation to detect knots in green softwood lumber. Signal attenuation has proven less reliable for hardwood species and for application to green lumber where moisture content may range from 60 to 150 percent. This paper reports on knot detection in green southern yellow pine and red oak lumber with a system that utilizes phase shift data to supplement attenuation data. Phase shift was found to be considerably more reliable than signal attenuation for knot detection in green lumber.

Utilization of Electrical Impedance Tomography to Detect Internal Anomalies in Southern Pine Logs

A large body of research has shown that knowledge of internal defect location in logs prior to sawing has the potential to significantly increase lumber value yield. This paper describes a relatively low‐capital log scanning technique based on Electrical Impedance Tomography (EIT) to image anomalies interior to sawlogs. Static testing results showed that knots, juvenile and compression wood internal to logs can be detected. Although resolution is lower than that of CT and NMR technologies, the low cost of this EIT application should render it competitive.

Detecting Rot in Power Poles with Radio Frequency Scanning

The potential for detecting rot in power poles with a radio frequency method was tested. Five pentachlorophenol‐treated pole sections containing both sound and decayed wood were obtained from out‐of‐service power poles. Sections were conditioned in 12‐percent equilibrium moisture content (EMC) conditions for 12 months prior to testing. Pole sections were scanned over their length by a laboratory prototype that applied 250, 500 and 2000 kHz radio frequency signals to opposed 1‐inch diameter metal electrodes in contact with the pole surface. Each capacitor pair scanned each pole cross sectionally at multiple positions along pole longitudinal axis. Signal voltage attenuation and phase shift values for sound and decayed wood sections were recorded. Radio frequency signals for sound wood were compared to those of decayed wood. Radio frequency signals of 2000 kHz yielded the greatest difference in attenuation and phase shift response between sound and decayed wood. For even the best‐performing 2000 kHz signal, ...