@article{ren_meng_chang_kelley_jameel_park_2017, title={Effect of blending ratio of loblolly pine wood and bark on the properties of pyrolysis bio-oils}, volume={167}, ISSN={["1873-7188"]}, DOI={10.1016/j.fuproc.2017.06.025}, abstractNote={Bark, which is available in abundance, has recently become a topic of interest when considering alternative materials for the production of pyrolysis bio-oil. Previous studies have revealed that the pyrolysis behavior of bark differs remarkably from that of wood in that bark typically generates a phase-separated bio-oil. In this study, blends of loblolly pine wood and bark were pyrolyzed to investigate the effect of blending ratio on the yield and properties of derived bio-oils. Trends of lower decomposition rate, decreased organic yield, and increased bio-char yield were observed as bark percentage in the feedstock increased, while the amount of levoglucosan in bio-oil increased. Pyrolysis reactivity, which includes yield and physical properties of the bio-oil, was found to have a linear relationship with the blending ratio of pine bark. It was found that blending up to 50% bark in the feedstock still produced a homogeneous bio-oil.}, journal={FUEL PROCESSING TECHNOLOGY}, author={Ren, Xueyong and Meng, Jiajia and Chang, Jianmin and Kelley, Stephen S. and Jameel, Hasan and Park, Sunkyu}, year={2017}, month={Dec}, pages={43–49} }
 @article{he_yoo_meng_yildiz_bradford_park_gao_2017, title={Engineering biorefinery residues from loblolly pine for supercapacitor applications}, volume={120}, ISSN={["1873-3891"]}, DOI={10.1016/j.carbon.2017.05.056}, abstractNote={Recycling agricultural waste biomass into high-value-added products is of great importance to offset the cost of biofuel production. Here, we make biochar-based activated carbons (BACs) from loblolly pine chips via different carbonization recipes and chemical activations. BACs were then assembled into electrochemical double-layer capacitors (EDLCs) as electrode materials. Surprisingly, pyrolysis at lower temperatures (300 °C and 350 °C) rendered better electrochemical performance of BACs than those done at higher temperatures (500 °C and 700 °C). This is mainly due to the large surface area and high pore volume generated at the lower temperatures. Among all the pyrolysis recipes, flash pyrolysis at 300 °C produced the BAC with the highest specific capacitance (74 F g−1 at 20 mV s−1), exceeding the specific capacitance of commercial activated carbon (NORIT®) by 45%. This report demonstrates the great potential of our refinery recipe to engineer BACs from the sustainable, affordable, and abundant natural wastes for energy-storage applications, which opens the door for a group of biorefinery residues for value-added applications.}, journal={CARBON}, author={He, Nanfei and Yoo, Seunghyun and Meng, Jiajia and Yildiz, Ozkan and Bradford, Philip D. and Park, Sunkyu and Gao, Wei}, year={2017}, month={Aug}, pages={304–312} }
 @article{meng_moore_tilotta_kelley_adhikari_parkt_2015, title={Thermal and Storage Stability of Bio-Oil from Pyrolysis of Torrefied Wood}, volume={29}, ISSN={["1520-5029"]}, DOI={10.1021/acs.energyfuels.5b00929}, abstractNote={The objective of this paper is to investigate the biomass torrefaction effect on bio-oil stability by comparing the physicochemical and compositional properties of aged bio-oils. Two aging methods, accelerated aging (held at 80 °C for 24 h) and long-term natural aging (12-month storage at 25 °C), were employed to produce aged bio-oils for such comparison. The results indicate that bio-oils made from heat-treated wood had similar aging behavior in terms of increase of water content, acid content, molecular weight, and viscosity. The increase rate, however, was found to be different and dependent on the aging method. The accelerated method found parallel water and total acidity number (TAN) increments between raw and torrefaction bio-oils, while the natural aging method found torrefaction bio-oils, especially those made from heavily treated wood, had much slower water and acid accumulation than that of raw bio-oil. As a negative effect, both methods identified the viscosity of torrefaction bio-oils increase...}, number={8}, journal={ENERGY & FUELS}, author={Meng, Jiajia and Moore, Andrew and Tilotta, David C. and Kelley, Stephen S. and Adhikari, Sushil and Parkt, Sunkyu}, year={2015}, month={Aug}, pages={5117–5126} }
 @article{meng_smirnova_song_moore_ren_kelley_park_tilotta_2014, title={Identification of free radicals in pyrolysis oil and their impact on bio-oil stability}, volume={4}, ISSN={["2046-2069"]}, DOI={10.1039/c4ra02007c}, abstractNote={The existence of radicals in pyrolysis oil generated from loblolly pine in three different reactor systems was verified with electron paramagnetic resonance (EPR) spectroscopy.}, number={56}, journal={RSC ADVANCES}, author={Meng, Jiajia and Smirnova, Tatyana I. and Song, Xiao and Moore, Andrew and Ren, Xueyong and Kelley, Stephen and Park, Sunkyu and Tilotta, David}, year={2014}, pages={29840–29846} }
 @article{ren_meng_moore_chang_gou_park_2014, title={Thermogravimetric investigation on the degradation properties and combustion performance of bio-oils}, volume={152}, ISSN={["1873-2976"]}, DOI={10.1016/j.biortech.2013.11.028}, abstractNote={The degradation properties and combustion performance of raw bio-oil, aged bio-oil, and bio-oil from torrefied wood were investigated through thermogravimetric analysis. A three-stage process was observed for the degradation of bio-oils, including devolatilization of the aqueous fraction and light compounds, transition of the heavy faction to solid, and combustion of carbonaceous residues. Pyrolysis kinetics parameters were calculated via the reaction order model and 3D-diffusion model, and combustion indexes were used to qualitatively evaluate the thermal profiles of tested bio-oils for comparison with commercial oils such as fuel oils. It was found that aged bio-oil was more thermally instable and produced more combustion-detrimental carbonaceous solid. Raw bio-oil and bio-oil from torrefied wood had comparable combustion performance to fuel oils. It was considered that bio-oil has a potential to be mixed with or totally replace the fuel oils in boilers.}, journal={BIORESOURCE TECHNOLOGY}, author={Ren, Xueyong and Meng, Jiajia and Moore, Andrew M. and Chang, Jianmin and Gou, Jinsheng and Park, Sunkyu}, year={2014}, month={Jan}, pages={267–274} }
 @article{meng_moore_tilotta_kelley_park_2014, title={Toward Understanding of Bio-Oil Aging: Accelerated Aging of Bio-Oil Fractions}, volume={2}, ISSN={2168-0485 2168-0485}, url={http://dx.doi.org/10.1021/sc500223e}, DOI={10.1021/sc500223e}, abstractNote={Pyrolysis bio-oil from biomass is a promising intermediate for producing transportation fuels and platform chemicals. However, its instability, often called aging, has been identified as a critical hurdle that prevents bio-oil from being commercialized. The objective of this research is to explore the bio-oil aging mechanism by an accelerated aging test of fractionated bio-oil produced from loblolly pine. When water soluble (WS), ether insoluble (EIS), and pyrolytic lignin (PL) fractions were aged separately, the increased molecular weight (Mw) was observed with increasing aging temperature and the presence of acids. WS and EIS fractions had high Mw brown solids formed after aging. Adjusting the pH of WS and EIS fractions from 2.5 to 7.0 significantly reduced the tendency of a Mw increase. Similar Mw rise was also observed on a PL fraction with an elevated temperature and acid addition. Formaldehyde was found to react with the PL fraction in the presence of any acid catalysts tested, i.e., 8-fold Mw incre...}, number={8}, journal={ACS Sustainable Chemistry & Engineering}, publisher={American Chemical Society (ACS)}, author={Meng, Jiajia and Moore, Andrew and Tilotta, David and Kelley, Stephen and Park, Sunkyu}, year={2014}, month={Jul}, pages={2011–2018} }
 @article{park_meng_lim_rojas_park_2013, title={Transformation of lignocellulosic biomass during torrefaction}, volume={100}, ISSN={["0165-2370"]}, DOI={10.1016/j.jaap.2012.12.024}, abstractNote={In this study, the effect of torrefaction on the chemical and structural transformation of lignocellulosic biomass was investigated using complementary analytical tools. It was observed that the acid-insoluble fraction was increased from approximately 30 to 38% and the methoxyl content was decreased to about half after torrefaction at 330 °C for 2.5 min. These results highlight the formation of condensed structures along with lignin transformation via demethoxylation. Solid-state NMR spectroscopy indicated that upon torrefaction the aromaticity increased from about 36 to 60%. For the sample torrefied at 330 °C, the non-protonated aromatic carbon fraction was found to be about 60% of total aromatic carbons, indicating the formation of large aromatic clusters. The complementary analyses used in this study are proposed as a suitable approach for the elucidation of chemical and structural transformation of biomass during thermal treatment.}, journal={JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS}, author={Park, Junyeong and Meng, Jiajia and Lim, Kwang Hun and Rojas, Orlando J. and Park, Sunkyu}, year={2013}, month={Mar}, pages={199–206} }
 @article{meng_park_tilotta_park_2012, title={The effect of torrefaction on the chemistry of fast-pyrolysis bio-oil}, volume={111}, ISSN={["0960-8524"]}, DOI={10.1016/j.biortech.2012.01.159}, abstractNote={Fast pyrolysis was performed on torrefied loblolly pine and the collected bio-oils were analyzed to compare the effect of the torrefaction treatment on their quality. The results of the analyses show that bio-oils produced from torrefied wood have improved oxygen-to-carbon ratios compared to those from the original wood with the penalty of a decrease in bio-oil yield. The extent of this improvement depends on the torrefaction severity. Based on the GC/MS analysis of the pyrolysis bio-oils, bio-oils produced from torrefied biomass show different compositions compared to that from the original wood. Specifically, the former becomes more concentrated in pyrolytic lignin with less water content than the latter. It was considered that torrefaction could be a potential upgrading method to improve the quality of bio-oil, which might be a useful feedstock for phenolic-based chemicals.}, journal={BIORESOURCE TECHNOLOGY}, author={Meng, Jiajia and Park, Junyeong and Tilotta, David and Park, Sunkyu}, year={2012}, month={May}, pages={439–446} }