@article{ahn_wang_kim_you_jung_seong_choi_park_choi_kim_2024, title={Catalyst-recirculating system in steam explosion pretreatment for producing high-yield of xylooligosaccharides from oat husk}, volume={342}, ISSN={["1879-1344"]}, DOI={10.1016/j.carbpol.2024.122411}, abstractNote={We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively.}, journal={CARBOHYDRATE POLYMERS}, author={Ahn, Myeong Rok and Wang, Song and Kim, Jonghwa and You, Sang-Mook and Jung, Chan -Duck and Seong, Hyolin and Choi, June -Ho and Park, Sunkyu and Choi, In-Gyu and Kim, Hoyong}, year={2024}, month={Oct} }
 @article{xu_rios_wang_ham_choi_kim_park_2024, title={Process design and techno-economic analysis for the lignin oil solvent recovery and purification process}, volume={434}, ISSN={["1879-1786"]}, url={http://dx.doi.org/10.1016/j.jclepro.2023.139999}, DOI={10.1016/j.jclepro.2023.139999}, abstractNote={A technology to extract lignin oil from pretreated biomass has been developed for a cosmetic additive application (i.e., UV protection) through isopropyl alcohol without any catalyst. It was used for co-product lignin oil with XOS from a biorefinery process in this study. One of the key factors impacting economic feasibility is extraction solvent recovery, and it is important to design the process details based on techno-economic analysis. Therefore, this study has integrated lab experiments, process designs with Aspen Plus process simulations, and Excel-based techno-economic analysis to investigate the effect of solvent recovery on overall economics. Three options for solvent recovery (e.g., distillation, salting-out, and molecular sieve) have been explored. The salting-out method showed the best economic performance with an IRR of 33.6%, while the distillation method was 21.7% and the molecular sieve method was 16.7%. Key parameters are also identified by sensitivity analyses, which indicate the improvement potential for each case. This study has laid a foundation for lignin oil production studies, but its concept and approach can be applied to any solvent recycling in a biorefinery process, which is often neglected in lab-scale biorefinery studies.}, journal={JOURNAL OF CLEANER PRODUCTION}, author={Xu, Yiling and Rios, David Cruz and Wang, Song and Ham, Choonghyun and Choi, June-Ho and Kim, Hoyong and Park, Sunkyu}, year={2024}, month={Jan} }
 @article{chen_shetty_wang_nellipudi_aziz_xu_sargsyan_2024, title={Techno-Economic and Environmental Analyses of an Integrated Liquefied Natural Gas/Allam-Fetvedt Cycle/Air Separation Unit Complex}, volume={17}, ISSN={["1996-1073"]}, DOI={10.3390/en17112663}, abstractNote={The natural gas (NG)-powered compressors/engines used in liquified natural gas (LNG) plants are a major source of methane emission. The Allam–Fetvedt cycle (AFC), an oxyfuel, carbon-neutral, high-efficiency power plant, generates pipeline-grade CO2. This work performed novel process modeling, economic analysis, and greenhouse gas emissions analysis for a heat-integrated, electrified LNG/AFC/air separation unit (ASU) complex (LAA), then compared it to standalone LNG and AFC/ASU plants (baseline) as well as an LNG plant electrified with AFC/ASU without heat integration. The low-grade heat generated from compressors of the LNG plant can enhance the AFC net power output by 7.1%. Utilizing the nitrogens cold energy reduces the compressor power requirement by 1.6%. In the integrated LAA complex, not only are GHG emissions avoided, but the energy efficiencies are also improved for both the LNG plant and the AFC power plant. A cash flow analysis of LAA was performed over a 20-year period with 5%, 7%, and 10% discount rates and three levels of LNG prices. The 45Q CO2 credit of USD 85/T as stipulated by the recent Inflation Reduction Act (IRA) of 2022 has been incorporated. The results clearly indicate the economic and environmental benefits of the proposed electrification and heat/power integration.}, number={11}, journal={ENERGIES}, author={Chen, Daniel and Shetty, Pawanahamsa and Wang, Song and Nellipudi, Veeracharyulu and Aziz, Fuad and Xu, Qiang and Sargsyan, Gevorg}, year={2024}, month={Jun} }