Praveen Meduri

Electrospun PDMS membranes with tailored solvent-responsive shrinkage and folding are demonstrated. The membranes are used as soft robotic traps, self-sealing membranes, and oxygen-permeable films to enhance photocatalytic H ₂ O ₂ generation.

This project evaluates the economics of pyrolyzing eastern redcedar to produce bio-oil, and subsequent upgradation through a hydrogenation process, reducing its oxygen content and improving its energy density to meet conventional fuel heating values. The process simulation was carried out using Aspen Plus software, and the yields of biochar, bio-oil, and syngas from pyrolysis, which were modeled using a Ryield reactor at 450 °C, were derived from an experimental source selected for its detailed analysis of bio-oil compounds and their precise thermodynamic representation. Equipment and utility costing was performed using Aspen Economic Analyzer (AEA), and CAPCOST software. To accurately define the properties of eastern redcedar and biochar in Aspen Plus, the HCOALGEN model was selected to compute density, while the DECOALIGT model was employed for enthalpy calculations. Both models are reliable methods for handling non-conventional solids in Aspen Plus. The estimated annual fuel production after water removal was 39,903 kg at a biomass feed rate of 100 kg hr ^-1 . In this process, biochar after pyrolysis was separated in a cyclone, and the vapor (bio-oil and syngas) was cooled, condensed, and separated into bio-oil and syngas in a knockout drum. Another separator was used to separate the water from the bio-oil. Thermal upgradation of bio-oil (water-free) is conducted in a RStoic reactor at 450 °C and 105 bar. Figure 1a is an Aspen Plus flowsheet that represents the generation of bio-oil from eastern redcedar as well as its thermal upgradation. The reactor was modeled to upgrade a select group of oxygenated compounds that significantly contribute to the higher heating value (HHV). Oxygen-free compounds that contribute minimally to HHV were not included in the upgradation to avoid consumption of expensive hydrogen, which would unnecessarily increase operating expenses without improving fuel quality. The wastewater generated after the upgradation was separated from the final fuel product. The built-in alkaline electrolyzer designed for water splitting was used for hydrogen generation in the electrochemical upgradation process. The electrochemical approach eliminates the need for the high-pressure pump and preheater required in the thermal process. The pump, heater, and RStoic reactor from the thermal section were replaced by a single electrolyzer unit (Figure 1b). The upgradation process reduced the oxygen content of the water-free bio-oil from 28.30 wt.% to < 20 wt.%, which, in turn, increased the HHV, estimated using Dulong’s equation, from 26.7 MJ kg ^-1 to 35.3 MJ kg ^-1 , rendering the final product with a HHV close to that of conventional fuels. The results of the economic analysis showed an estimated plant capital expenditures (CAPEX) at $1.33 million for the thermal pathway and $0.97 million for the electrochemical pathway, with corresponding estimated annual operating expenditures (OPEX) of $0.47 million and $0.45 million, respectively. The discounted cash flow analysis (DCFROR) with an internal rate of return of 10% and a project life of 10 years was used to determine the minimum fuel selling price (MFSP) of the upgraded bio-oil, which were estimated to be $18.4 kg ^-1 and $16.1 kg ^-1 for the thermal and electrochemical pathways, respectively. The resulting fuel prices were higher than the current market rates, indicating the need to further refine the process via catalytic pyrolysis, heat integration, and/or upgrading unit operations, thus facilitating the scaling up of upgraded fuel production. These findings provide preliminary economic insights into bio-oil production from eastern redcedar for future research. Figure 1

Photocatalytic hydrogen peroxide (H₂O₂) production using a Z-scheme copper bismuth oxide and molybdenum sulfide photocatalyst.