L. Mark Risse

Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry Litter

Abstract Raw poultry litter has certain drawbacks for energy production such as high ash and moisture content, a corrosive nature, and low heating values. A combined solution to utilization of raw poultry litter may involve fractionation and pyrolysis. Fractionation divides poultry litter into a fine, nutrient-rich fraction and a coarse, carbon-dense fraction. Pyrolysis of the coarse fraction would remove the corrosive volatiles as bio-oil, leaving clean char. This paper presents the effect of fractionation and pyrolysis process parameters on the calorific value of char and on the characterization of bio-oil. Poultry litter samples collected from three commercial poultry farms were divided into 10 treatments that included 2 controls (raw poultry litter and its coarse fraction having particle size greater than 0.85 mm) and 8 other treatments that were combinations of three factors: type (raw poultry litter or its coarse fraction), heating rate (30 or 10 °C/min), and pyrolysis temperature (300 or 500 °C). After the screening process, the poultry litter samples were dried and pyrolyzed in a batch reactor under nitrogen atmosphere and char and condensate yields were recorded. The condensate was separated into three fractions on the basis of their density: heavy, medium, and light phase. Calorific value and proximate and nutrient analysis were performed for char, condensate, and feedstock. Results show that the char with the highest calorific value (17.39 ± 1.37 MJ/kg) was made from the coarse fraction at 300 °C, which captured 68.71 ± 9.37% of the feedstock energy. The char produced at 300 °C had 42 ± 11 mg/kg arsenic content but no mercury. Almost all of the Al, Ca, Fe, K, Mg, Na, and P remained in the char. The pyrolysis process reduced ammoniacal-nitrogen (NH4-N) in char by 99.14 ± 0.47% and nitrate-nitrogen (NO3-N) by 95.79 ± 5.45% at 500 °C.

Transforming Solid Wastes Into High Quality Bioenergy Products: Entropy Analysis

Although energy analysis of a pyrolysis system improves the thermal efficiency of the process, it did not account for the quality of energy used and produced from the process. This paper presents the entropy of analysis of converting solid wastes into useable bio-products during pyrolysis. The entropy balance was performed on a continuous flow pyrolysis reactor system using pine pellets as a feedstock at the pyrolysis temperature of 773 K. An interesting conclusion was drawn from the results that the pyrolysis process converted low quality and high entropy biomass into high quality and low entropy energy products char, bio-oil, and gases. The analysis concluded that the both pyrolysis and combustion were the process of low entropy production and most part of the irreversibility or positive entropy production was mainly associated with condenser unit. The high quality energy producing pyrolysis process may be included as part of the future biorefinery.

Climate research priorities for policy-makers, practitioners, and scientists in Georgia, USA

Climate change has far-reaching effects on human and ecological systems, requiring collaboration across sectors and disciplines to determine effective responses. To inform regional responses to climate change, decision-makers need credible and relevant information representing a wide swath of knowledge and perspectives. The southeastern U. S. State of Georgia is a valuable focal area for study because it contains multiple ecological zones that vary greatly in land use and economic activities, and it is vulnerable to diverse climate change impacts. We identified 40 important research questions that, if answered, could lay the groundwork for effective, science-based climate action in Georgia. Top research priorities were identified through a broad solicitation of candidate research questions (180 were received). A group of experts across sectors and disciplines gathered for a workshop to categorize, prioritize, and filter the candidate questions, identify missing topics, and rewrite questions. Participants then collectively chose the 40 most important questions. This cross-sectoral effort ensured the inclusion of a diversity of topics and questions (e.g., coastal hazards, agricultural production, ecosystem functioning, urban infrastructure, and human health) likely to be important to Georgia policy-makers, practitioners, and scientists. Several cross-cutting themes emerged, including the need for long-term data collection and consideration of at-risk Georgia citizens and communities. Workshop participants defined effective responses as those that take economic cost, environmental impacts, and social justice into consideration. Our research highlights the importance of collaborators across disciplines and sectors, and discussing challenges and opportunities that will require transdisciplinary solutions.

Efficiency Testing of New Silt Fence Materials

We compare SiltSaver belted strand retention fence with traditional type C silt fence with the goal of determining if it would be acceptable for use as a sediment barrier in Georgia. ASTM standard methods were used to evaluate flow through and sediment removal efficiency using three different site specific soils. For flow without sediment, there were no statistical differences, although the BSRF showed a slightly higher flow rate than the type C fence that was tested. Flow rates with sediment were generally 30% to 85% lower on the BSRF than the type C fence with the greater differences observed with the finer particle sizes and the double concentration runs. This indicates the influence of the soil particles on the flow rate and may suggest that the sediment trapped behind the fence is controlling the flow rate more than the fence itself. The results from the analysis of the effluent and sediment removal efficiency indicated that the BSRF was more effective at retaining the sediment behind the fence. Both the suspended solids content and the turbidity of the effluent was lower using the BSRF fence material than the Type C fence material for all test conditions. Sediment removal efficiencies for the BSRF were significantly higher for all three tested soils at both the single and double concentration. Additional tests were conducted using variations of the ASTM standard and these tests showed similar trends. While no testing program can provide results to prove an application will function under all conditions that will be encountered in the field, our testing indicates that the SiltSaver BSRF should be an effective alternative to standard Type C silt fence.