Wet organic wastes are especially troublesome in valorization. Therefore, innovative solutions are still in demand to make valorization feasible. In this study, we tested a new transformation route of a blackcurrant pomace as a high-moisture industrial waste through a series of high-temperature and pressure solvothermal liquefaction experiments. The feedstock was directly converted under near-critical conditions of the binary solvent system (water/2-propanol). The goal was to examine the effect of conversion parameters (temperature, biomass-to-solvent ratio) on the change in the yield of resultant bioproducts, as well as the quality thereof. The experiments were conducted in a batch autoclave at a temperature between 250 and 300 °C. The main product of the transformation was liquid biocrude, which was obtained with the highest yield (ca. 52 wt.%) at 275 °C. The quality of biocrude was examined by ATR-FTIR, GC-MS, and elemental analysis. The ultimate biocrude was a viscous heterogeneous mixture containing various groups of components and exhibiting evident energy densification (ca. 145–153%) compared to the value of the feedstock. The proposed processing method is suitable for further development toward efficient valorization technology. More specifically, the co-solvent additive for liquefaction is beneficial not only for the enhancement of the yield of the desired product, i.e., biocrude, but also in terms of technological aspects (reduction of operational pressure and temperature).

Spent coffee grounds (SCGs), a by-product of coffee brewing, have high application potential. However, their high moisture content complicates conventional conversion without energy-intensive drying. This study explores a new route to convert SCGs to high-carbon bioproducts, such as hydrochar and bio-oil, through hydrothermal processing. The effect of the processing variables, i.e., temperature, residence time, and the application of the binary solvent as a reaction medium, on the distribution of the resultant bioproducts was investigated. The quality of the fabricated bioproducts was analyzed by means of instrumental techniques such as EA, ATR-FTIR, GC-MS, and GC-TCD-FID. Two dominant fractions were liquid bio-oil and solid hydrochar. The highest char yield (39 wt.%) was observed under milder conditions (low T and short residence times), while more severe conditions led to an increase in bio-oil formation, which reached a maximum of 46 wt.%. The resulting bio-oils were of similar quality, presenting high carbon content (71–74 wt.%) and energetic values (approximately 35 MJ/kg). Also, hydrochars showed a noticeable energy densification compared to raw materials, where the C content and HHV reached up to 73.8 wt.% and 30 MJ/kg, respectively. The addition of co-solvent to water improves the bio-oil yield as a result of the enhanced stabilization of reactive intermediates.